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Colicino-Murbach E, Hathaway C, Dungrawala H. Replication fork stalling in late S-phase elicits nascent strand degradation by DNA mismatch repair. Nucleic Acids Res 2024:gkae721. [PMID: 39180395 DOI: 10.1093/nar/gkae721] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2023] [Revised: 07/03/2024] [Accepted: 08/06/2024] [Indexed: 08/26/2024] Open
Abstract
Eukaryotic chromosomal replication occurs in a segmented, temporal manner wherein open euchromatin and compact heterochromatin replicate during early and late S-phase respectively. Using single molecule DNA fiber analyses coupled with cell synchronization, we find that newly synthesized strands remain stable at perturbed forks in early S-phase. Unexpectedly, stalled forks are susceptible to nucleolytic digestion during late replication resulting in defective fork restart. This inherent vulnerability to nascent strand degradation is dependent on fork reversal enzymes and resection nucleases MRE11, DNA2 and EXO1. Inducing chromatin compaction elicits digestion of nascent DNA in response to fork stalling due to reduced association of RAD51 with nascent DNA. Furthermore, RAD51 occupancy at stalled forks in late S-phase is diminished indicating that densely packed chromatin limits RAD51 accessibility to mediate replication fork protection. Genetic analyses reveal that susceptibility of late replicating forks to nascent DNA digestion is dependent on EXO1 via DNA mismatch repair (MMR) and that the BRCA2-mediated replication fork protection blocks MMR from degrading nascent DNA. Overall, our findings illustrate differential regulation of fork protection between early and late replication and demonstrate nascent strand degradation as a critical determinant of heterochromatin instability in response to replication stress.
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Affiliation(s)
| | - Caitlin Hathaway
- Department of Molecular Biosciences, University of South Florida, Tampa, FL, USA
| | - Huzefa Dungrawala
- Department of Molecular Biosciences, University of South Florida, Tampa, FL, USA
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Khushman MM, Toboni MD, Xiu J, Manne U, Farrell A, Lou E, Shields AF, Philip PA, Salem ME, Abraham J, Spetzler D, Marshall J, Jayachandran P, Hall MJ, Lenz HJ, Sahin IH, Seeber A, Powell MA. Differential Responses to Immune Checkpoint Inhibitors are Governed by Diverse Mismatch Repair Gene Alterations. Clin Cancer Res 2024; 30:1906-1915. [PMID: 38350001 DOI: 10.1158/1078-0432.ccr-23-3004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2023] [Revised: 11/23/2023] [Accepted: 02/09/2024] [Indexed: 02/15/2024]
Abstract
PURPOSE The response to immune checkpoint inhibitors (ICI) in deficient mismatch repair (dMMR) colorectal cancer and endometrial cancer is variable. Here, we explored the differential response to ICIs according to different mismatch repair alterations. EXPERIMENTAL DESIGN Colorectal cancer (N = 13,701) and endometrial cancer (N = 3,315) specimens were tested at Caris Life Sciences. Median overall survival (mOS) was estimated using Kaplan-Meier. The prediction of high-, intermediate-, and low-affinity epitopes by tumor mutation burden (TMB) values was conducted using R-squared (R2). RESULTS Compared with mutL (MLH1 and PMS2) co-loss, the mOS was longer in mutS (MSH2 and MSH6) co-loss in all colorectal cancer (54.6 vs. 36 months; P = 0.0.025) and endometrial cancer (81.5 vs. 48.2 months; P < 0.001) patients. In ICI-treated patients, the mOS was longer in mutS co-loss in colorectal cancer [not reached (NR) vs. 36 months; P = 0.011). In endometrial cancer, the mOS was NR vs. 42.2 months; P = 0.711]. The neoantigen load (NAL) in mutS co-loss compared with mutL co-loss was higher in colorectal cancer (high-affinity epitopes: 25.5 vs. 19; q = 0.017, intermediate: 39 vs. 32; q = 0.004, low: 87.5 vs. 73; q < 0.001) and endometrial cancer (high-affinity epitopes: 15 vs. 11; q = 0.002, intermediate: 27.5 vs. 19; q < 0.001, low: 59 vs. 41; q < 0.001), respectively. R2 ranged from 0.25 in mutS co-loss colorectal cancer to 0.95 in mutL co-loss endometrial cancer. CONCLUSIONS Patients with mutS co-loss experienced longer mOS in colorectal cancer and endometrial cancer and better response to ICIs in colorectal cancer. Among all explored biomarkers, NAL was higher in mutS co-loss and may be a potential driving factor for the observed better outcomes. TMB did not reliably predict NAL.
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Affiliation(s)
- Moh'd M Khushman
- Washington University in St. Louis/Siteman Cancer Center, St. Louis, Missouri
| | - Michael D Toboni
- The University of Alabama at Birmingham/O'Neal Comprehensive Cancer Center, Birmingham, Alabama
| | | | - Upender Manne
- The University of Alabama at Birmingham/O'Neal Comprehensive Cancer Center, Birmingham, Alabama
| | | | - Emil Lou
- University of Minnesota/Masonic Cancer Center, Minneapolis, Minnesota
| | - Anthony F Shields
- Wayne State University/Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | - Philip A Philip
- Wayne State University/Barbara Ann Karmanos Cancer Institute, Detroit, Michigan
| | | | | | | | - John Marshall
- Georgetown University/Georgetown Lombardi Comprehensive Cancer Center, Washington, District of Columbia
| | - Priya Jayachandran
- University of South California/Norris Comprehensive Cancer Center, Los Angeles, California
| | | | - Heinz-Josef Lenz
- University of South California/Norris Comprehensive Cancer Center, Los Angeles, California
| | - Ibrahim Halil Sahin
- University of Pittsburgh Medical Center/Hillman Cancer Center, Pittsburgh, Pennsylvania
| | - Andreas Seeber
- Medical University of Innsbruck, Comprehensive Cancer Center Innsbruck, Innsbruck, Austria
| | - Mathew A Powell
- Washington University in St. Louis/Siteman Cancer Center, St. Louis, Missouri
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Yang SR, Gedvilaite E, Ptashkin R, Chang J, Ziegler J, Mata DA, Villafania LB, Nafa K, Hechtman JF, Benayed R, Zehir A, Benhamida J, Arcila ME, Mandelker D, Rudin CM, Paik PK, Drilon A, Schoenfeld AJ, Ladanyi M. Microsatellite Instability and Mismatch Repair Deficiency Define a Distinct Subset of Lung Cancers Characterized by Smoking Exposure, High Tumor Mutational Burden, and Recurrent Somatic MLH1 Inactivation. J Thorac Oncol 2024; 19:409-424. [PMID: 37838086 PMCID: PMC10939956 DOI: 10.1016/j.jtho.2023.10.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/16/2023]
Abstract
INTRODUCTION Microsatellite instability (MSI) and mismatch repair (MMR) deficiency represent a distinct oncogenic process and predict response to immune checkpoint inhibitors (ICIs). The clinicopathologic features of MSI-high (MSI-H) and MMR deficiency (MMR-D) in lung cancers remain poorly characterized. METHODS MSI status from 5171 patients with NSCLC and 315 patients with SCLC was analyzed from targeted next-generation sequencing data using two validated bioinformatic pipelines. RESULTS MSI-H and MMR-D were identified in 21 patients with NSCLC (0.41%) and six patients with SCLC (1.9%). Notably, all patients with NSCLC had a positive smoking history, including 11 adenocarcinomas. Compared with microsatellite stable cases, MSI-H was associated with exceptionally high tumor mutational burden (37.4 versus 8.5 muts/Mb, p < 0.0001), MMR mutational signatures (43% versus 0%, p < 0.0001), and somatic biallelic alterations in MLH1 (52% versus 0%, p < 0.0001). Loss of MLH1 and PMS2 expression by immunohistochemistry was found in MLH1 altered and wild-type cases. Similarly, the majority of patients with MSI-H SCLC had evidence of MLH1 inactivation, including two with MLH1 promoter hypermethylation. A single patient with NSCLC with a somatic MSH2 mutation had Lynch syndrome as confirmed by the presence of a germline MSH2 mutation. Among patients with advanced MSI-H lung cancers treated with ICIs, durable clinical benefit was observed in three of eight patients with NSCLC and two of two patients with SCLC. In NSCLC, STK11, KEAP1, and JAK1 were mutated in nonresponders but wild type in responders. CONCLUSIONS We present a comprehensive clinicogenomic landscape of MSI-H lung cancers and reveal that MSI-H defines a rare subset of lung cancers associated with smoking, high tumor mutational burden, and MLH1 inactivation. Although durable clinical benefit to ICI was observed in some patients, the broad range of responses suggests that clinical activity may be modulated by co-mutational landscapes.
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Affiliation(s)
- Soo-Ryum Yang
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York.
| | - Erika Gedvilaite
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ryan Ptashkin
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jason Chang
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - John Ziegler
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Douglas A Mata
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Liliana B Villafania
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Khedoudja Nafa
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jaclyn F Hechtman
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ryma Benayed
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Ahmet Zehir
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Jamal Benhamida
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Maria E Arcila
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Diana Mandelker
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Charles M Rudin
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Paul K Paik
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Alexander Drilon
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Adam J Schoenfeld
- Department of Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
| | - Marc Ladanyi
- Department of Pathology and Laboratory Medicine, Memorial Sloan Kettering Cancer Center, New York, New York
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Fu X, Huang J, Fan X, Wang C, Deng W, Tan X, Chen Z, Cai Y, Hanjie L, Xu L, Zou J, Zhan H, Huang S, Fang Y, Huang Y. Head-to-head comparative study: evaluating three panels for MSI-PCR testing in patients with colorectal and gastric cancer. J Clin Pathol 2023:jcp-2023-209089. [PMID: 38053280 DOI: 10.1136/jcp-2023-209089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Accepted: 11/15/2023] [Indexed: 12/07/2023]
Abstract
AIMS Due to the lack of large clinical cohorts in the Chinese populations with colorectal cancer (CRC) and gastric cancer (GC), there is no consensus among the preferred panel for microsatellite instability (MSI)-PCR testing. This study aims to evaluate a more appropriate panel. METHODS We tested the MSI status of 2572 patients with CRC and GC using the NCI panel and 2 mononucleotide panels (5 and 6 mononucleotide panels). Immunohistochemistry (IHC) was employed to perform mismatch repair protein testing in 1976 samples. RESULTS We collected 2572 patients with CRC and GC. The National Cancer Institute (NCI) panel failed to detect 13 cases. Of the 2559 cases that received results from all three panels, 2544 showed consistent results. In the remaining 15 cases, 9 showed discrepancies between MSI-H and MSI-L, and 6 showed discrepancies between MSI-L and microsatellite stability (MSS). The misdiagnosis rate of MSI-L was significantly lower in two mononucleotide panels than in the NCI panel (12.5% vs 87.5%, p=0.010) in CRC. In patients with GC, only the NCI panel detected three MSI-L cases, while the results of the two mononucleotide panels were one MSI-H and two MSS. Based on their IHC results, the MSI-L misdiagnosis rate of the NCI panel was 33.3%. Furthermore, compared with two mononucleotide panels, the NCI panel had a much lower rate of all loci instability in CRC (90.8% and 90.3% vs 25.2%) and GC (89.5% and 89.5% vs 12.0%). CONCLUSION In Chinese patients with CRC and GC, the five and six mononucleotide panels have advantages for detecting MSI over the NCI panel.
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Affiliation(s)
- Xinhui Fu
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jinglin Huang
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xinjuan Fan
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Chao Wang
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Weihao Deng
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Xiaoli Tan
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Zhiting Chen
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yacheng Cai
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Lin Hanjie
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Liang Xu
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Jiaxin Zou
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Department of General Surgery, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Huanmiao Zhan
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Shuhui Huang
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yongzhen Fang
- Biomedical Innovation Center, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
- Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
| | - Yan Huang
- Department of Pathology, The Sixth Affiliated Hospital, Sun Yat-sen University, Guangzhou, China
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Chung Y, Nam SK, Chang HE, Lee C, Kang GH, Lee HS, Park KU. Evaluation of an eight marker-panel including long mononucleotide repeat markers to detect microsatellite instability in colorectal, gastric, and endometrial cancers. BMC Cancer 2023; 23:1100. [PMID: 37953261 PMCID: PMC10641958 DOI: 10.1186/s12885-023-11607-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 11/02/2023] [Indexed: 11/14/2023] Open
Abstract
BACKGROUND Accurate determination of microsatellite instability (MSI) status is critical for optimal treatment in cancer patients. Conventional MSI markers can sometimes display subtle shifts that are difficult to interpret, especially in non-colorectal cases. We evaluated an experimental eight marker-panel including long mononucleotide repeat (LMR) markers for detection of MSI. METHODS The eight marker-panel was comprised of five conventional markers (BAT-25, BAT-26, NR-21, NR-24, and NR-27) and three LMR markers (BAT-52, BAT-59 and BAT-62). MSI testing was performed against 300 specimens of colorectal, gastric, and endometrial cancers through PCR followed by capillary electrophoresis length analysis. RESULTS The MSI testing with eight marker-panel showed 99.3% (295/297) concordance with IHC analysis excluding 3 MMR-focal deficient cases. The sensitivity of BAT-59 and BAT-62 was higher than or comparable to that of conventional markers in gastric and endometrial cancer. The mean shift size was larger in LMR markers compared to conventional markers for gastric and endometrial cancers. CONCLUSIONS The MSI testing with eight maker-panel showed comparable performance with IHC analysis. The LMR markers, especially BAT-59 and BAT-62, showed high sensitivity and large shifts which can contribute to increased confidence in MSI classification, especially in gastric and endometrial cancers. Further study is needed with large number of samples for the validation of these LMR markers.
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Affiliation(s)
- Yousun Chung
- Department of Laboratory Medicine, Kangdong Sacred Heart Hospital, Seoul, Republic of Korea
| | - Soo Kyung Nam
- Department of Interdisciplinary Program in Cancer Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Ho Eun Chang
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Cheol Lee
- Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pathology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Gyeong Hoon Kang
- Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Pathology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Hye Seung Lee
- Department of Pathology, Seoul National University College of Medicine, Seoul, Republic of Korea.
- Department of Pathology, Seoul National University Hospital, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
| | - Kyoung Un Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Republic of Korea.
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, 82 Gumi-ro 173, Bundang-gu, Seongnam, 13620, Republic of Korea.
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Toboni MD, Wu S, Farrell A, Xiu J, Ribeiro JR, Oberley MJ, Arend R, Erickson BK, Herzog TJ, Thaker PH, Powell MA. Differential outcomes and immune checkpoint inhibitor response among endometrial cancer patients with MLH1 hypermethylation versus MLH1 "Lynch-like" mismatch repair gene mutation. Gynecol Oncol 2023; 177:132-141. [PMID: 37683549 DOI: 10.1016/j.ygyno.2023.08.015] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2023] [Revised: 08/22/2023] [Accepted: 08/24/2023] [Indexed: 09/10/2023]
Abstract
OBJECTIVES To identify differential survival outcomes and immune checkpoint inhibitor (ICI) response in MLH1 hypermethylated versus MLH1 mutated ("Lynch-like") endometrial tumors and determine whether their molecular profiles can elucidate the differential outcomes. METHODS 1673 mismatch repair deficient endometrial tumors were analyzed by next-generation sequencing and whole transcriptome sequencing (Caris Life Sciences, Phoenix, AZ). PD-L1, ER, and PR were tested by immunohistochemistry and immune cell infiltrates were calculated using MCP-counter. Significance was determined using Chi-square and Mann-Whitney U tests and adjusted for multiple comparisons. Overall survival (OS) was depicted using Kaplan-Meier survival curves. RESULTS The endometrial cancer cohort comprised 89.2% patients with MLH1 hypermethylated tumors and 10.8% with MLH1 mutated tumors, with median ages of 67 and 60 years, respectively (p < 0.01). Patients with MLH1 hypermethylated tumors had significantly worse OS and trended toward worse OS following ICI treatment than patients with MLH1 mutated tumors. The immune microenvironment of MLH1 hypermethylated relative to MLH1 mutated was characterized by decreased PD-L1 positivity, immune checkpoint gene expression, immune cell infiltration, T cell inflamed scores, and interferon gamma (IFNγ) scores. MLH1 hypermethylation was also associated with decreased mutation rates in TP53 and DNA damage repair genes, but increased rates of JAK1, FGFR2, CCND1, and PTEN mutations, as well as increased ER and PR positivity. CONCLUSIONS Endometrial cancer patients with MLH1 hypermethylation display significantly decreased survival and discrepant immunotherapy responses compared to patients with MLH1 mutated tumors, which was associated with differential mutational profiles, a more immune cold phenotype, and increased ER/PR expression in MLH1 hypermethylated tumors. Providers may consider early transition from single agent ICI to a multi-agent regimen or hormonal therapy for patients with MLH1 hypermethylated tumors.
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Affiliation(s)
- Michael D Toboni
- University of Alabama at Birmingham, Division of Gynecologic Oncology, Birmingham, AL, USA.
| | - Sharon Wu
- Caris Life Sciences, Phoenix, AZ, USA
| | | | | | | | | | - Rebecca Arend
- UAB Comprehensive Cancer Center Experimental Therapeutics Program, Birmingham, AL, USA
| | - Britt K Erickson
- University of Minnesota, Division of Gynecologic Oncology, Minneapolis, MN, USA
| | | | - Premal H Thaker
- Washington University School of Medicine, Division of Gynecologic Oncology, St. Louis, MO, USA
| | - Matthew A Powell
- Washington University School of Medicine, Division of Gynecologic Oncology, St. Louis, MO, USA
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Mo J, Borcherding N, Jo S, Tithi TI, Cho E, Cash KE, Honda M, Wang L, Ahmed KK, Weigel R, Spies M, Kolb R, Zhang W. Contrasting roles of different mismatch repair proteins in basal-like breast cancer. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.20.549745. [PMID: 37745359 PMCID: PMC10515760 DOI: 10.1101/2023.07.20.549745] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/26/2023]
Abstract
The mismatch repair (MMR) pathway is known as a tumor suppressive pathway and genes involved in MMR are commonly mutated in hereditary colorectal or other cancer types. However, the function of MMR genes/proteins in breast cancer progression and metastasis are largely unknown. We found that MSH2, but not MLH1, is highly enriched in basal-like breast cancer (BLBC) and that its protein expression is inversely correlated with overall survival time (OS). MSH2 expression is frequently elevated due to genomic amplification or gain-of-expression in BLBC, which results in increased MSH2 protein to pair with MSH6 (collectively referred to as MutSα). Genetic deletion of MSH2 or MLH1 results in a contrasting phenotype in metastasis, with MSH2-deletion leading to reduced metastasis and MLH1-deletion to enhanced liver or lung metastasis. Mechanistically, MSH2-deletion induces the expression of a panel of chemokines in BLBC via epigenetic and/or transcriptional regulation, which leads to an immune reactive tumor microenvironment (TME) and elevated immune cell infiltrations. MLH1 is not correlated with chemokine expression and/or immune cell infiltration in BLBC, but its deletion results in strong accumulation of neutrophils that are known for metastasis promotion. Our study supports the differential functions of MSH2 and MLH1 in BLBC progression and metastasis, which challenges the paradigm of the MMR pathway as a universal tumor suppressive mechanism.
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Affiliation(s)
- Jiao Mo
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- Current: R & D, Thermo Fisher Scientific, Alachua, FL 32615, USA
| | - Nicholas Borcherding
- Department of Pathology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
- Current: Department of Pathology and Immunology, Washington University School of Medicine, St Louis, MO 63110, USA
| | - Sung Jo
- Department of Pathology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
- Current: R & D, Carbon Biosciences, Waltham, MA 02451
| | - Tanzia Islam Tithi
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Edward Cho
- Department of Pathology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
- Department of Surgery, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
| | - Kailey E Cash
- Department of Biochemistry and Molecular Biology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
| | - Masayoshi Honda
- Department of Biochemistry and Molecular Biology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
| | - Lei Wang
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
| | - Kawther K. Ahmed
- Department of Pathology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
- Current: Department of Pharmaceutics, the University of Baghdad College of Pharmacy, Bab-almoadham, PO Box 14026, Baghdad, Iraq
| | - Ronald Weigel
- Department of Surgery, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
| | - Maria Spies
- Department of Biochemistry and Molecular Biology, the University of Iowa Carver College of Medicine, Iowa City, IA, 52242
| | - Ryan Kolb
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- University of Florida Health Cancer Center (UFHCC), the University of Florida, Gainesville, FL 32610, USA
| | - Weizhou Zhang
- Department of Pathology, Immunology and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL 32610, USA
- University of Florida Health Cancer Center (UFHCC), the University of Florida, Gainesville, FL 32610, USA
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Guan J, Li GM. DNA mismatch repair in cancer immunotherapy. NAR Cancer 2023; 5:zcad031. [PMID: 37325548 PMCID: PMC10262306 DOI: 10.1093/narcan/zcad031] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/08/2023] [Accepted: 06/07/2023] [Indexed: 06/17/2023] Open
Abstract
Tumors defective in DNA mismatch repair (dMMR) exhibit microsatellite instability (MSI). Currently, patients with dMMR tumors are benefitted from anti-PD-1/PDL1-based immune checkpoint inhibitor (ICI) therapy. Over the past several years, great progress has been made in understanding the mechanisms by which dMMR tumors respond to ICI, including the identification of mutator phenotype-generated neoantigens, cytosolic DNA-mediated activation of the cGAS-STING pathway, type-I interferon signaling and high tumor-infiltration of lymphocytes in dMMR tumors. Although ICI therapy shows great clinical benefits, ∼50% of dMMR tumors are eventually not responsive. Here we review the discovery, development and molecular basis of dMMR-mediated immunotherapy, as well as tumor resistant problems and potential therapeutic interventions to overcome the resistance.
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Affiliation(s)
- Junhong Guan
- Cuiying Biomedical Research Center, Lanzhou University Second Hospital, Lanzhou, Gansu 730030, China
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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9
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Boland CR, Koi M, Hawn MT, Carethers JM, Yurgelun MB. Serendipity Strikes: How Pursuing Novel Hypotheses Shifted the Paradigm Regarding the Genetic Basis of Colorectal Cancer and Changed Cancer Therapy. Dig Dis Sci 2023; 68:3504-3513. [PMID: 37402979 PMCID: PMC11262588 DOI: 10.1007/s10620-023-08006-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/19/2023] [Indexed: 07/06/2023]
Abstract
In this installment of the "Paradigm Shifts in Perspective" series, the authors, all scientists who have been involved in colorectal cancer (CRC) research for most or all of their careers, have watched the field develop from early pathological descriptions of tumor formation to the current understanding of tumor pathogenesis that informs personalized therapies. We outline how our understanding of the pathogenetic basis of CRC began with seemingly isolated discoveries-initially with the mutations in RAS and the APC gene, the latter of which was initially found in the context of intestinal polyposis, to the more complex process of multistep carcinogenesis, to the chase for tumor suppressor genes, which led to the unexpected discovery of microsatellite instability (MSI). These discoveries enabled the authors to better understand how the DNA mismatch repair (MMR) system not only recognizes DNA damage but also responds to damage by DNA repair or by triggering apoptosis in the injured cell. This work served, in part, to link the earlier findings on the pathogenesis of CRC to the development of immune checkpoint inhibitors, which has been transformative-and curative-for certain types of CRCs and other cancers as well. These discoveries also highlight the circuitous routes that scientific progress takes, which can include thoughtful hypothesis testing and at other times recognizing the importance of seemingly serendipitous observations that substantially change the flow and direction of the discovery process. What has happened over the past 37 years was not predictable when this journey began, but it does speak to the power of careful scientific experimentation, following the facts, perseverance in the face of opposition, and the willingness to think outside of established paradigms.
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Affiliation(s)
| | | | - Mary T Hawn
- Department of Surgery, Stanford University School of Medicine, CJ Huang Bldg, Palo Alto, CA, 94306, USA
| | | | - Matthew B Yurgelun
- Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA
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10
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Fu Y, Yang B, Cui Y, Hu X, Li X, Lu F, Qin T, Zhang L, Hu Z, Guo E, Fan J, Xiao R, Li W, Qin X, Hu D, Peng W, Liu J, Wang B, Mills GB, Chen G, Sun C. BRD4 inhibition impairs DNA mismatch repair, induces mismatch repair mutation signatures and creates therapeutic vulnerability to immune checkpoint blockade in MMR-proficient tumors. J Immunother Cancer 2023; 11:jitc-2022-006070. [PMID: 37072347 PMCID: PMC10124306 DOI: 10.1136/jitc-2022-006070] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/20/2023] [Indexed: 04/20/2023] Open
Abstract
BACKGROUND Mismatch repair deficiency (dMMR) is a well-recognized biomarker for response to immune checkpoint blockade (ICB). Strategies to convert MMR-proficient (pMMR) to dMMR phenotype with the goal of sensitizing tumors to ICB are highly sought. The combination of bromodomain containing 4 (BRD4) inhibition and ICB provides a promising antitumor effect. However, the mechanisms underlying remain unknown. Here, we identify that BRD4 inhibition induces a persistent dMMR phenotype in cancers. METHODS We confirmed the correlation between BRD4 and mismatch repair (MMR) by the bioinformatic analysis on The Cancer Genome Atlas and Clinical Proteomic Tumor Analysis Consortium data, and the statistical analysis on immunohistochemistry (IHC) scores of ovarian cancer specimens. The MMR genes (MLH1,MSH2,MSH6,PMS2) were measured by quantitative reverse transcription PCR, western blot, and IHC. The MMR status was confirmed by whole exome sequencing, RNA sequencing, MMR assay and hypoxanthine-guanine phosphoribosyl transferase gene mutation assay. The BRD4i AZD5153 resistant models were induced both in vitro and in vivo. The transcriptional effects of BRD4 on MMR genes were investigated by chromatin immunoprecipitation among cell lines and data from the Cistrome Data Browser. The therapeutic response to ICB was testified in vivo. The tumor immune microenvironment markers, such as CD4, CD8, TIM-3, FOXP3, were measured by flow cytometry. RESULTS We identified the positive correlation between BRD4 and MMR genes in transcriptional and translational aspects. Also, the inhibition of BRD4 transcriptionally reduced MMR genes expression, resulting in dMMR status and elevated mutation loads. Furthermore, prolonged exposure to AZD5153 promoted a persistent dMMR signature both in vitro and in vivo, enhancing tumor immunogenicity, and increased sensitivity to α-programmed death ligand-1 therapy despite the acquired drug resistance. CONCLUSIONS We demonstrated that BRD4 inhibition suppressed expression of genes critical to MMR, dampened MMR, and increased dMMR mutation signatures both in vitro and in vivo, sensitizing pMMR tumors to ICB. Importantly, even in BRD4 inhibitors (BRD4i)-resistant tumor models, the effects of BRD4i on MMR function were maintained rendering tumors sensitive to ICB. Together, these data identified a strategy to induce dMMR in pMMR tumors and further, indicated that BRD4i sensitive and resistant tumors could benefit from immunotherapy.
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Affiliation(s)
- Yu Fu
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Bin Yang
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Yaoyuan Cui
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xingyuan Hu
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Xi Li
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Funian Lu
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Tianyu Qin
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Li Zhang
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Zhe Hu
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Ensong Guo
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Junpeng Fan
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Rourou Xiao
- Department of Obstetrics and Gynecology, Zhongnan Hospital of Wuhan University, Wuhan, Hubei, People's Republic of China
| | - Wenting Li
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- Department of Obstetrics and Gynecology, The First Affiliated Hospital of Shihezi University, Shihezi, Xinjiang, People's Republic of China
| | - Xu Qin
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- Department of Stomatology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Dianxing Hu
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Wenju Peng
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Jingbo Liu
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Beibei Wang
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Gordon B Mills
- Department of Cell, Development and Cancer Biology, Oregon Health & Science University Knight Cancer Institute, Portland, Oregon, USA
| | - Gang Chen
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
| | - Chaoyang Sun
- Department of Gynecological Oncology, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
- National Clinical Research Center for Gynecology and Obstetrics, Tongji Hospital of Tongji Medical College of Huazhong University of Science and Technology, Wuhan, Hubei, People's Republic of China
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Morrison KR, Wang T, Chan KY, Trotter EW, Gillespie A, Michael MZ, Oakhill JS, Hagan IM, Petersen J. Elevated basal AMP-activated protein kinase activity sensitizes colorectal cancer cells to growth inhibition by metformin. Open Biol 2023; 13:230021. [PMID: 37042113 PMCID: PMC10090877 DOI: 10.1098/rsob.230021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2023] [Accepted: 03/09/2023] [Indexed: 04/13/2023] Open
Abstract
Expression and activity of the AMP-activated protein kinase (AMPK) α1 catalytic subunit of the heterotrimeric kinase significantly correlates with poor outcome for colorectal cancer patients. Hence there is considerable interest in uncovering signalling vulnerabilities arising from this oncogenic elevation of AMPKα1 signalling. We have therefore attenuated mammalian target of rapamycin (mTOR) control of AMPKα1 to generate a mutant colorectal cancer in which AMPKα1 signalling is elevated because AMPKα1 serine 347 cannot be phosphorylated by mTORC1. The elevated AMPKα1 signalling in this HCT116 α1.S347A cell line confers hypersensitivity to growth inhibition by metformin. Complementary chemical approaches confirmed this relationship in both HCT116 and the genetically distinct HT29 colorectal cells, as AMPK activators imposed vulnerability to growth inhibition by metformin in both lines. Growth inhibition by metformin was abolished when AMPKα1 kinase was deleted. We conclude that elevated AMPKα1 activity modifies the signalling architecture in such a way that metformin treatment compromises cell proliferation. Not only does this mutant HCT116 AMPKα1-S347A line offer an invaluable resource for future studies, but our findings suggest that a robust biomarker for chronic AMPKα1 activation for patient stratification could herald a place for the well-tolerated drug metformin in colorectal cancer therapy.
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Affiliation(s)
- Kaitlin R. Morrison
- Flinders Health and Medical Research Institute, Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA 5042, Australia
| | - Tingting Wang
- Flinders Health and Medical Research Institute, Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA 5042, Australia
| | - Kuan Yoow Chan
- Cancer Research UK Manchester Institute, Alderley Park, Macclesfield SK10 4TG, UK
| | - Eleanor W. Trotter
- Cancer Research UK Manchester Institute, Alderley Park, Macclesfield SK10 4TG, UK
| | - Ari Gillespie
- Flinders Health and Medical Research Institute, Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA 5042, Australia
| | - Michael Z. Michael
- Flinders Health and Medical Research Institute, Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA 5042, Australia
- Flinders Centre for Innovation in Cancer, Dept. Gastroenterology and Hepatology, Flinders Medical Centre, Bedford Park, SA 5042, Australia
| | - Jonathan S. Oakhill
- Metabolic Signalling Laboratory, St Vincent's Institute of Medical Research, School of Medicine, University of Melbourne, Victoria 3065, Australia
- Mary MacKillop Institute for Health Research, Australian Catholic University, Victoria 3000, Australia
| | - Iain M. Hagan
- Cancer Research UK Manchester Institute, Alderley Park, Macclesfield SK10 4TG, UK
| | - Janni Petersen
- Flinders Health and Medical Research Institute, Flinders Centre for Innovation in Cancer, Flinders University, Adelaide, SA 5042, Australia
- Nutrition and Metabolism, SouthAustralia Health and Medical Research Institute, Adelaide, SA 5000, Australia
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12
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Hitchins MP, Alvarez R, Zhou L, Aguirre F, Dámaso E, Pineda M, Capella G, Wong JJL, Yuan X, Ryan SR, Sathe DS, Baxter MD, Cannon T, Biswas R, DeMarco T, Grzelak D, Hampel H, Pearlman R. MLH1-methylated endometrial cancer under 60 years of age as the "sentinel" cancer in female carriers of high-risk constitutional MLH1 epimutation. Gynecol Oncol 2023; 171:129-140. [PMID: 36893489 PMCID: PMC10153467 DOI: 10.1016/j.ygyno.2023.02.017] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2023] [Revised: 02/22/2023] [Accepted: 02/26/2023] [Indexed: 03/11/2023]
Abstract
OBJECTIVE Universal screening of endometrial carcinoma (EC) for mismatch repair deficiency (MMRd) and Lynch syndrome uses presence of MLH1 methylation to omit common sporadic cases from follow-up germline testing. However, this overlooks rare cases with high-risk constitutional MLH1 methylation (epimutation), a poorly-recognized mechanism that predisposes to Lynch-type cancers with MLH1 methylation. We aimed to determine the role and frequency of constitutional MLH1 methylation among EC cases with MMRd, MLH1-methylated tumors. METHODS We screened blood for constitutional MLH1 methylation using pyrosequencing and real-time methylation-specific PCR in patients with MMRd, MLH1-methylated EC ascertained from (i) cancer clinics (n = 4, <60 years), and (ii) two population-based cohorts; "Columbus-area" (n = 68, all ages) and "Ohio Colorectal Cancer Prevention Initiative (OCCPI)" (n = 24, <60 years). RESULTS Constitutional MLH1 methylation was identified in three out of four patients diagnosed between 36 and 59 years from cancer clinics. Two had mono-/hemiallelic epimutation (∼50% alleles methylated). One with multiple primaries had low-level mosaicism in normal tissues and somatic "second-hits" affecting the unmethylated allele in all tumors, demonstrating causation. In the population-based cohorts, all 68 cases from the Columbus-area cohort were negative and low-level mosaic constitutional MLH1 methylation was identified in one patient aged 36 years out of 24 from the OCCPI cohort, representing one of six (∼17%) patients <50 years and one of 45 patients (∼2%) <60 years in the combined cohorts. EC was the first/dual-first cancer in three patients with underlying constitutional MLH1 methylation. CONCLUSIONS A correct diagnosis at first presentation of cancer is important as it will significantly alter clinical management. Screening for constitutional MLH1 methylation is warranted in patients with early-onset EC or synchronous/metachronous tumors (any age) displaying MLH1 methylation.
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Affiliation(s)
- Megan P Hitchins
- Department of Biomedical Sciences, Cedars-Sinai Cancer, Cedars-Sinai Medical Center, Los Angeles, CA, USA; Department of Medicine (Oncology), Stanford University, Stanford, CA, USA.
| | - Rocio Alvarez
- Department of Biomedical Sciences, Cedars-Sinai Cancer, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Lisa Zhou
- Department of Biomedical Sciences, Cedars-Sinai Cancer, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Francesca Aguirre
- Department of Biomedical Sciences, Cedars-Sinai Cancer, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Estela Dámaso
- Department of Medicine (Oncology), Stanford University, Stanford, CA, USA; Hereditary Cancer Program, Catalan Institute of Oncology, Institut d'Investigació Biomèdica de Bellvitge (IDIBELL), ONCOBELL Program, Av. Gran Via de l'Hospitalet, 199-203, 08908 L' Hospitalet de Llobregat, Barcelona, Spain; Molecular Genetics Unit, Elche University Hospital, Elche, Alicante. Foundation for the Promotion of Health and Biomedical Research of Valencia Region (FISABIO), FISABIO- Elche Health Department, Spain
| | - Marta Pineda
- Molecular Genetics Unit, Elche University Hospital, Elche, Alicante. Foundation for the Promotion of Health and Biomedical Research of Valencia Region (FISABIO), FISABIO- Elche Health Department, Spain; Consortium for Biomedical Research in Cancer - CIBERONC, Carlos III Institute of Health, Av. De Monforte de Lemos 5, 28029 Madrid, Spain
| | - Gabriel Capella
- Molecular Genetics Unit, Elche University Hospital, Elche, Alicante. Foundation for the Promotion of Health and Biomedical Research of Valencia Region (FISABIO), FISABIO- Elche Health Department, Spain; Consortium for Biomedical Research in Cancer - CIBERONC, Carlos III Institute of Health, Av. De Monforte de Lemos 5, 28029 Madrid, Spain
| | - Justin J-L Wong
- Epigenetics and RNA Biology Program Centenary Institute, and Faculty of Medicine and Health, The University of Sydney, Camperdown, New South Wales 2050, Australia
| | - Xiaopu Yuan
- Department of Pathology and Laboratory Medicine, Cedars-Sinai Cancer, Cedars-Sinai Medical Center, Los Angeles, CA, USA
| | - Shawnia R Ryan
- Hereditary Cancer Assessment Program, University of New Mexico Comprehensive Cancer Center, NM, USA
| | - Devika S Sathe
- Precision Medicine and Genetics, Frederick Health, MD, USA
| | | | - Timothy Cannon
- Cancer Genetics Program, Inova Schar Cancer Institute, Inova Fairfax Hospital, VA, USA
| | - Rakesh Biswas
- Cancer Genetics Program, Inova Schar Cancer Institute, Inova Fairfax Hospital, VA, USA
| | - Tiffani DeMarco
- Cancer Genetics Program, Inova Schar Cancer Institute, Inova Fairfax Hospital, VA, USA
| | | | - Heather Hampel
- Department of Internal Medicine and the Comprehensive Cancer Center, Ohio State University, Columbus, OH, USA; Division of Clinical Cancer Genomics, Department of Medical Oncology and Therapeutics Research, City of Hope National Medical Center, Duarte, CA, USA
| | - Rachel Pearlman
- Department of Internal Medicine and the Comprehensive Cancer Center, Ohio State University, Columbus, OH, USA
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13
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Molecular Targeted Therapy in Oncology Focusing on DNA Repair Mechanisms. Arch Med Res 2022; 53:807-817. [PMID: 36460545 DOI: 10.1016/j.arcmed.2022.11.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 11/17/2022] [Indexed: 11/30/2022]
Abstract
DNA repair mechanisms are essential for maintaining cellular homeostasis. Malfunction of these repair mechanisms leads to cellular DNA mutations, carcinogenic transformation, and cell death. These same defects also create vulnerabilities that are relatively specific to cancer cells, and which could potentially be exploited to increase the therapeutic index of anticancer treatments and thereby improve patient outcomes. The targeted therapy based on inhibiting the DNA damage response (DDR) opens a new therapeutic landscape for patients with deficient DDR. Currently there are two DNA repair mechanisms that are used as targets for molecular therapies: Mitsmach Repair (MMR) and Homologous Recombination Repair (HRR). These molecular targets allow for immunotherapy treatments based on "checkpoint inhibitors" (ICIs) drugs and "PARP inhibitor" (PARPi) drugs in different solid tumors. In this review we will describe the state of the art of this interesting mechanism and explain the options for treatment based on these alterations. Moreover, many clinical trials are currently underway exploring better treatment options for dMMR and HRD patients with different solid tumours.
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Sankar K, Ye JC, Li Z, Zheng L, Song W, Hu-Lieskovan S. The role of biomarkers in personalized immunotherapy. Biomark Res 2022; 10:32. [PMID: 35585623 PMCID: PMC9118650 DOI: 10.1186/s40364-022-00378-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2021] [Accepted: 04/20/2022] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Immune checkpoint inhibitors have revolutionized cancer therapeutic paradigm and substantially improved the survival of patients with advanced malignancies. However, a significant limitation is the wide variability in clinical response. MAIN TEXT Several biomarkers have been evaluated in prior and ongoing clinical trials to investigate their prognostic and predictive role of patient response, nonetheless, most have not been comprehensively incorporated into clinical practice. We reviewed published data regarding biomarkers that have been approved by the United States Food and Drug Administration as well as experimental tissue and peripheral blood biomarkers currently under investigation. We further discuss the role of current biomarkers to predict response and response to immune checkpoint inhibitors and the promise of combination biomarker strategies. Finally, we discuss ideal biomarker characteristics, and novel platforms for clinical trial design including enrichment and stratification strategies, all of which are exciting and dynamic to advance the field of precision immuno-oncology. CONCLUSION Incorporation and standardization of strategies to guide selection of combination biomarker approaches will facilitate expansion of the clinical benefit of immune checkpoint inhibitor therapy to appropriate subsets of cancer patients.
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Affiliation(s)
- Kamya Sankar
- Division of Hematology/Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Jing Christine Ye
- Division of Hematology/Oncology, Department of Internal Medicine, University of Michigan, Ann Arbor, MI, USA
- Rogel Cancer Center, University of Michigan, Ann Arbor, MI, USA
| | - Zihai Li
- Pelotonia Institute for Immuno-Oncology, The Ohio State University, Columbus, OH, USA
| | - Lei Zheng
- Johns Hopkins University, Baltimore, MD, USA
| | - Wenru Song
- Kira Pharmaceuticals, Cambridge, MA, USA
| | - Siwen Hu-Lieskovan
- Division of Medical Oncology, University of Utah, Salt Lake City, UT, USA.
- Huntsman Cancer Institute, Salt Lake City, UT, USA.
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15
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Steele CD, Pillay N, Alexandrov LB. An overview of mutational and copy number signatures in human cancer. J Pathol 2022; 257:454-465. [PMID: 35420163 PMCID: PMC9324981 DOI: 10.1002/path.5912] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2022] [Revised: 04/08/2022] [Accepted: 04/11/2022] [Indexed: 11/17/2022]
Abstract
The genome of each cell in the human body is constantly under assault from a plethora of exogenous and endogenous processes that can damage DNA. If not successfully repaired, DNA damage generally becomes permanently imprinted in cells, and all their progenies, as somatic mutations. In most cases, the patterns of these somatic mutations contain the tell‐tale signs of the mutagenic processes that have imprinted and are termed mutational signatures. Recent pan‐cancer genomic analyses have elucidated the compendium of mutational signatures for all types of small mutational events, including (1) single base substitutions, (2) doublet base substitutions, and (3) small insertions/deletions. In contrast to small mutational events, where, in most cases, DNA damage is a prerequisite, aneuploidy, which refers to the abnormal number of chromosomes in a cell, usually develops from mistakes during DNA replication. Such mistakes include DNA replication stress, mitotic errors caused by faulty microtubule dynamics, or cohesion defects that contribute to chromosomal breakage and can lead to copy number (CN) alterations (CNAs) or even to structural rearrangements. These aberrations also leave behind genomic scars which can be inferred from sequencing as CN signatures and rearrangement signatures. The analyses of mutational signatures of small mutational events have been extensively reviewed, so we will not comprehensively re‐examine them here. Rather, our focus will be on summarising the existing knowledge for mutational signatures of CNAs. As studying CN signatures is an emerging field, we briefly summarise the utility that mutational signatures of small mutational events have provided in basic science, cancer treatment, and cancer prevention, and we emphasise the future role that CN signatures may play in each of these fields. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.
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Affiliation(s)
- Christopher D Steele
- Research Department of Pathology, Cancer Institute, University College London, London, UK
| | - Nischalan Pillay
- Research Department of Pathology, Cancer Institute, University College London, London, UK.,Department of Cellular and Molecular Pathology, Royal National Orthopaedic Hospital NHS Trust, Stanmore, UK
| | - Ludmil B Alexandrov
- Department of Cellular and Molecular Medicine, UC San Diego, La Jolla, CA, USA.,Department of Bioengineering, UC San Diego, La Jolla, CA, USA.,Moores Cancer Center, UC San Diego, La Jolla, CA, USA
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Abstract
Colorectal cancer is the second leading cause of cancer-associated mortality, with a lifetime risk of approximately 4% to 5%. Colorectal cancer develops from the sequential acquisition of defined genetic mutations in the colonic epithelium. Tumorigenesis from normal tissue to cancer occurs largely through 3 pathways: the chromosomal instability pathway, the microsatellite instability pathway, and the sessile serrated pathway. Colorectal cancer incidence and mortality have decreased by approximately 35% since the beginning of screening programs in the 1990s, although other factors such as use of aspirin for coronary disease prevention and decreased smoking rates may also be important. In this review, we discuss the etiology, epidemiology, and histology of colorectal polyps and cancer.
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Polymerase Epsilon-Associated Ultramutagenesis in Cancer. Cancers (Basel) 2022; 14:cancers14061467. [PMID: 35326618 PMCID: PMC8946778 DOI: 10.3390/cancers14061467] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 03/09/2022] [Accepted: 03/09/2022] [Indexed: 01/27/2023] Open
Abstract
With advances in next generation sequencing (NGS) technologies, efforts have been made to develop personalized medicine, targeting the specific genetic makeup of an individual. Somatic or germline DNA Polymerase epsilon (PolE) mutations cause ultramutated (>100 mutations/Mb) cancer. In contrast to mismatch repair-deficient hypermutated (>10 mutations/Mb) cancer, PolE-associated cancer is primarily microsatellite stable (MSS) In this article, we provide a comprehensive review of this PolE-associated ultramutated tumor. We describe its molecular characteristics, including the mutation sites and mutation signature of this type of tumor and the mechanism of its ultramutagenesis. We discuss its good clinical prognosis and elucidate the mechanism for enhanced immunogenicity with a high tumor mutation burden, increased neoantigen load, and enriched tumor-infiltrating lymphocytes. We also provide the rationale for immune checkpoint inhibitors in PolE-mutated tumors.
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18
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Zhuang Y, Liu J, Wu H, Zhu Q, Yan Y, Meng H, Chen PR, Yi C. Increasing the efficiency and precision of prime editing with guide RNA pairs. Nat Chem Biol 2022; 18:29-37. [PMID: 34711981 DOI: 10.1038/s41589-021-00889-1] [Citation(s) in RCA: 57] [Impact Index Per Article: 28.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 08/26/2021] [Indexed: 12/20/2022]
Abstract
The recently reported prime editor (PE) can produce all types of base substitution, insertion and deletion, greatly expanding the scope of genome editing. However, improving the editing efficiency and precision of PE represents a major challenge. Here, we report an approach termed the homologous 3' extension mediated prime editor (HOPE). HOPE uses paired prime editing guide RNAs (pegRNAs) encoding the same edits in both sense and antisense DNA strands to achieve high editing efficiency in human embryonic kidney 293T cells as well as mismatch repair-deficient human colorectal carcinoma 116 cells. In addition, we found that HOPE shows greatly improved product purity compared to the original PE3 system. We envision that this enhanced tool could broaden both fundamental research and therapeutic applications of prime editing.
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Affiliation(s)
- Yuan Zhuang
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Jiangle Liu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Hao Wu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Qingguo Zhu
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Yongchang Yan
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
| | - Haowei Meng
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China
| | - Peng R Chen
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China
| | - Chengqi Yi
- State Key Laboratory of Protein and Plant Gene Research, School of Life Sciences, Peking University, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China.
- Department of Chemical Biology and Synthetic and Functional Biomolecules Center, College of Chemistry and Molecular Engineering, Peking University, Beijing, China.
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19
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Barroso-González J, García-Expósito L, Galaviz P, Lynskey ML, Allen JAM, Hoang S, Watkins SC, Pickett HA, O'Sullivan RJ. Anti-recombination function of MutSα restricts telomere extension by ALT-associated homology-directed repair. Cell Rep 2021; 37:110088. [PMID: 34879271 PMCID: PMC8724847 DOI: 10.1016/j.celrep.2021.110088] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 09/13/2021] [Accepted: 11/10/2021] [Indexed: 01/02/2023] Open
Abstract
Alternative lengthening of telomeres (ALT) is a telomere-elongation mechanism observed in ~15% of cancer subtypes. Current models indicate that ALT is mediated by homology-directed repair mechanisms. By disrupting MSH6 gene expression, we show that the deficiency of MutSα (MSH2/MSH6) DNA mismatch repair complex causes striking telomere hyperextension. Mechanistically, we show MutSα is specifically recruited to telomeres in ALT cells by associating with the proliferating-cell nuclear antigen (PCNA) subunit of the ALT telomere replisome. We also provide evidence that MutSα counteracts Bloom (BLM) helicase, which adopts a crucial role in stabilizing hyper-extended telomeres and maintaining the survival of MutSα-deficient ALT cancer cells. Lastly, we propose a model in which MutSα deficiency impairs heteroduplex rejection, leading to premature initiation of telomere DNA synthesis that coincides with an accumulation of telomere variant repeats (TVRs). These findings provide evidence that the MutSα DNA mismatch repair complex acts to restrain unwarranted ALT. Barroso-Gonzalez et al. show that the mismatch repair complex MutSα restricts the alternative lengthening of telomeres (ALT) pathway in cancer cells. MutSα has an anti-recombination function and limits recombination between heteroduplex sequences at telomeres, in part by counteracting the Bloom helicase (BLM).
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Affiliation(s)
- Jonathan Barroso-González
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Laura García-Expósito
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Pablo Galaviz
- Bioinformatics Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Michelle Lee Lynskey
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Joshua A M Allen
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - SongMy Hoang
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Simon C Watkins
- Department of Cell Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA
| | - Hilda A Pickett
- Telomere Length Regulation Unit, Children's Medical Research Institute, Faculty of Medicine and Health, University of Sydney, Westmead, NSW 2145, Australia
| | - Roderick J O'Sullivan
- Department of Pharmacology and Chemical Biology, School of Medicine, University of Pittsburgh School of Medicine, Pittsburgh, PA 15261, USA.
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20
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Lin JH, Chen S, Pallavajjala A, Guedes LB, Lotan TL, Bacher JW, Eshleman JR. Validation of Long Mononucleotide Repeat Markers for Detection of Microsatellite Instability. J Mol Diagn 2021; 24:144-157. [PMID: 34864149 DOI: 10.1016/j.jmoldx.2021.10.011] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 09/23/2021] [Accepted: 10/27/2021] [Indexed: 01/22/2023] Open
Abstract
Mismatch repair deficiency (dMMR) predicts response to immune checkpoint inhibitor therapy in solid tumors. Long mononucleotide repeat (LMR) markers may improve the interpretation of microsatellite instability (MSI) assays. Our cohorts included mismatch repair (MMR) proficient and dMMR colorectal cancer (CRC) samples, MMR proficient and dMMR endometrial cancer (EC) samples, dMMR prostate cancer samples, MSI-high (MSI-H) samples of other cancer types, and MSI-low (MSI-L) samples of various cancer types. MMR status was determined by immunohistochemical staining and/or MSI Analysis System Version 1.2 (V1.2). The sensitivity and specificity of the LMR MSI panel for dMMR detection were both 100% in CRC. The sensitivity values of the MSI V1.2 and LMR MSI panels in EC were 88% and 98%, respectively, and the specificity values were both 100%. The sensitivity of the LMR panel was 75% in dMMR prostate cancer detected by immunohistochemistry. The 22 samples of other cancer types that were previously classified as MSI-H were also classified as MSI-H using the LMR MSI panel. For the 12 samples that were previously classified as MSI-L, 1 sample was classified as microsatellite stable using the LMR MSI panel, 8 as MSI-L, and 3 as MSI-H. The LMR MSI panel showed high concordance to the MSI V1.2 panel in CRC and greater sensitivity in EC. The LMR MSI panel improves dMMR detection in noncolorectal cancers.
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Affiliation(s)
- John H Lin
- The Sol Goldman Pancreatic Cancer Research Center, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Suping Chen
- The Sol Goldman Pancreatic Cancer Research Center, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Aparna Pallavajjala
- The Sol Goldman Pancreatic Cancer Research Center, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Liana B Guedes
- The Sol Goldman Pancreatic Cancer Research Center, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | - Tamara L Lotan
- The Sol Goldman Pancreatic Cancer Research Center, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland; The Sol Goldman Pancreatic Cancer Research Center, Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland
| | | | - James R Eshleman
- The Sol Goldman Pancreatic Cancer Research Center, Department of Pathology, The Johns Hopkins University School of Medicine, Baltimore, Maryland; The Sol Goldman Pancreatic Cancer Research Center, Department of Oncology, The Johns Hopkins University School of Medicine, Baltimore, Maryland.
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21
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Chen PJ, Hussmann JA, Yan J, Knipping F, Ravisankar P, Chen PF, Chen C, Nelson JW, Newby GA, Sahin M, Osborn MJ, Weissman JS, Adamson B, Liu DR. Enhanced prime editing systems by manipulating cellular determinants of editing outcomes. Cell 2021; 184:5635-5652.e29. [PMID: 34653350 PMCID: PMC8584034 DOI: 10.1016/j.cell.2021.09.018] [Citation(s) in RCA: 327] [Impact Index Per Article: 109.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2021] [Revised: 08/09/2021] [Accepted: 09/09/2021] [Indexed: 12/26/2022]
Abstract
While prime editing enables precise sequence changes in DNA, cellular determinants of prime editing remain poorly understood. Using pooled CRISPRi screens, we discovered that DNA mismatch repair (MMR) impedes prime editing and promotes undesired indel byproducts. We developed PE4 and PE5 prime editing systems in which transient expression of an engineered MMR-inhibiting protein enhances the efficiency of substitution, small insertion, and small deletion prime edits by an average 7.7-fold and 2.0-fold compared to PE2 and PE3 systems, respectively, while improving edit/indel ratios by 3.4-fold in MMR-proficient cell types. Strategic installation of silent mutations near the intended edit can enhance prime editing outcomes by evading MMR. Prime editor protein optimization resulted in a PEmax architecture that enhances editing efficacy by 2.8-fold on average in HeLa cells. These findings enrich our understanding of prime editing and establish prime editing systems that show substantial improvement across 191 edits in seven mammalian cell types.
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Affiliation(s)
- Peter J Chen
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02141, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Jeffrey A Hussmann
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Department of Microbiology and Immunology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Jun Yan
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA
| | - Friederike Knipping
- Department of Pediatrics, University of Minnesota, Minneapolis, MN 55454, USA; Center for Genome Engineering, University of Minnesota, Minneapolis, MN 55108, USA; Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Purnima Ravisankar
- Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA
| | - Pin-Fang Chen
- Human Neuron Core, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Cidi Chen
- Human Neuron Core, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - James W Nelson
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02141, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Gregory A Newby
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02141, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA
| | - Mustafa Sahin
- Human Neuron Core, Rosamund Stone Zander Translational Neuroscience Center, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA; Harvard Medical School, Boston, MA 02115, USA
| | - Mark J Osborn
- Department of Pediatrics, University of Minnesota, Minneapolis, MN 55454, USA; Center for Genome Engineering, University of Minnesota, Minneapolis, MN 55108, USA; Stem Cell Institute, University of Minnesota, Minneapolis, MN 55455, USA
| | - Jonathan S Weissman
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, CA 94158, USA; Howard Hughes Medical Institute, University of California, San Francisco, San Francisco, CA 94158, USA; Whitehead Institute for Biomedical Research, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Britt Adamson
- Department of Molecular Biology, Princeton University, Princeton, NJ 08544, USA; Lewis-Sigler Institute for Integrative Genomics, Princeton University, Princeton, NJ 08544, USA.
| | - David R Liu
- Merkin Institute of Transformative Technologies in Healthcare, Broad Institute of Harvard and MIT, Cambridge, MA 02141, USA; Department of Chemistry and Chemical Biology, Harvard University, Cambridge, MA 02138, USA; Howard Hughes Medical Institute, Harvard University, Cambridge, MA 02138, USA.
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22
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Sahin IH, Goyal S, Pumpalova Y, Sonbol MB, Das S, Haraldsdottir S, Ahn D, Ciombor KK, Chen Z, Draper A, Berlin J, Bekaii‐Saab T, Lesinski GB, El‐Rayes BF, Wu C. Mismatch Repair (MMR) Gene Alteration and BRAF V600E Mutation Are Potential Predictive Biomarkers of Immune Checkpoint Inhibitors in MMR-Deficient Colorectal Cancer. Oncologist 2021; 26:668-675. [PMID: 33631043 PMCID: PMC8342606 DOI: 10.1002/onco.13741] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Accepted: 12/21/2020] [Indexed: 01/13/2023] Open
Abstract
BACKGROUND Immune checkpoint inhibitor (ICI) therapy is highly effective in metastatic mismatch repair-deficient (MMR-D) colorectal cancer (CRC). In this study, we evaluated molecular and clinical predictors of ICI response in MMR-D CRC. MATERIALS AND METHODS Patient databases at four cancer institutions were queried. The Fisher exact test was performed to test the association of clinical and molecular markers. The Kaplan-Meier method was used to estimate progression-free survival (PFS) and compared by the log-rank test. Twelve- and 24-month PFS rates were compared by the Z test. RESULTS A total of 60 patients with CRC with MMR-D/microsatellite instability-high who previously received ICIs were identified. Patients with liver metastasis had a lower overall response rate as compared with other sites of metastasis (36.4% vs. 68.7%; p = .081). Patients with MLH1/PMS2 loss had worse 1-year and 2-year PFS rates compared with patients with MSH2/MSH6 loss (84.2% vs. 57.8% and 78.2% vs. 54.2%, respectively; p < .001). There were improved 1-year and 2-year PFS rates in patients with wild-type BRAF when compared with patients with BRAF V600E mutation (73.3% vs. 40%, and 73.3% vs. 26.7%; respectively; p < .001). Patients aged >65 had significantly worse PFS rates as compared with patients aged ≤65 (p < .001). CONCLUSION BRAF V600E mutation, MLH1 and/or PMS2 loss, as well as age >65 years and liver metastasis, may be predictive of duration of ICI response in patients with MMR-D CRC. Larger cohorts are needed to confirm our findings. IMPLICATIONS FOR PRACTICE The results of this study reveal clinically important biomarkers that potentially predict immune checkpoint inhibitor response in patients with mismatch repair-deficient colorectal cancer.
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Affiliation(s)
| | - Subir Goyal
- Emory University School of Medicine, Winship Cancer InstituteAtlantaGeorgiaUSA
| | | | | | - Satya Das
- Vanderbilt University Ingram Cancer CenterNashvilleTennesseeUSA
| | | | | | | | - Zhengjia Chen
- Emory University School of Medicine, Winship Cancer InstituteAtlantaGeorgiaUSA
| | - Amber Draper
- Emory University School of Medicine, Winship Cancer InstituteAtlantaGeorgiaUSA
| | - Jordan Berlin
- Vanderbilt University Ingram Cancer CenterNashvilleTennesseeUSA
| | | | - Gregory B. Lesinski
- Emory University School of Medicine, Winship Cancer InstituteAtlantaGeorgiaUSA
| | - Bassel F. El‐Rayes
- Emory University School of Medicine, Winship Cancer InstituteAtlantaGeorgiaUSA
| | - Christina Wu
- Emory University School of Medicine, Winship Cancer InstituteAtlantaGeorgiaUSA
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23
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Tan E, Sahin IH. Defining the current role of immune checkpoint inhibitors in the treatment of mismatch repair-deficient/microsatellite stability-high colorectal cancer and shedding light on future approaches. Expert Rev Gastroenterol Hepatol 2021; 15:735-742. [PMID: 33539189 DOI: 10.1080/17474124.2021.1886077] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Introduction: Mismatch repair deficient (MMR-D)/microsatellite instability-high (MSI-H) colorectal cancer (CRC) carries unique biologic features including high tumor mutation burden, increased amount of mutation-associated neoantigen generation, and the presence of marked tumor-infiltrating lymphocytes. Immune checkpoint inhibitor (ICI) therapy has rapidly changed the treatment algorithm of MMR-D/MSI-H CRC.Areas covered: In this review article, we discuss the recent data regarding the use of ICIs in metastatic MMR-D/MSI-H CRC patients. We also elaborated on potential biomarkers of ICI response and innovative therapeutic approaches that may prevail resistance mechanisms for the treatment of MMR-D/MSI-H colorectal cancer.Expert opinion: Pembrolizumab was recently granted approval by the FDA as first-line therapy for metastatic MMR-D/MSI-H CRC based on the results of the Keynote 177 study. The combination of nivolumab and ipilimumab will also likely be a choice for the initial therapy of MMR-D/MSI-H CRC in the near future. More therapeutic modalities with novel immunomodulatory agents as well as targeted therapy directed to immune resistance pathways are needed. The novel approaches discussed in this review article will define potential treatment options for the management of MMR-D/MSI-H CRC patients who progress on first-line ICI therapy.
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Affiliation(s)
- Elaine Tan
- Department of Gastrointestinal Oncology, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
| | - Ibrahim Halil Sahin
- Department of Gastrointestinal Oncology, H Lee Moffitt Cancer Center and Research Institute, Tampa, FL, USA
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24
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Mismatch Repair Deficiency as a Predictive and Prognostic Biomarker in Molecularly Classified Endometrial Carcinoma. Cancers (Basel) 2021; 13:cancers13133124. [PMID: 34206702 PMCID: PMC8268938 DOI: 10.3390/cancers13133124] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2021] [Revised: 06/19/2021] [Accepted: 06/21/2021] [Indexed: 11/16/2022] Open
Abstract
Simple Summary We studied mismatch repair (MMR) deficiency as a predictive and prognostic biomarker in endometrial carcinoma. MMR deficiency was associated with poor outcome only when p53 aberrant and polymerase-ϵ mutant tumors were excluded from the MMR proficient subgroup, in accordance with molecular classification based on The Cancer Genome Atlas. MMR deficiency was associated with an increased risk of death in the absence of various clinicopathologic risk factors, but the outcome was not worsened when such risk factors were present. The proportion of pelvic relapses and lymphatic dissemination, defined as primary lymph node involvement or relapses in regional lymph nodes, were higher in the MMR deficient subgroup. In conclusion, the effect of MMR deficiency on the outcome of endometrial carcinoma depends on how MMR proficiency is defined. MMR deficiency is associated with an increased risk of death in the absence of established risk factors and a unique pattern of disease spread. Abstract The aggressiveness of mismatch repair (MMR) deficient endometrial carcinomas was examined in a single institution retrospective study. Outcomes were similar for MMR proficient (n = 508) and deficient (n = 287) carcinomas, identified by immunohistochemistry. In accordance with molecular classification based on The Cancer Genome Atlas (TCGA), tumors with abnormal p53 staining or polymerase-ϵ exonuclease domain mutation were excluded from the MMR proficient subgroup, termed as “no specific molecular profile” (NSMP). Compared with NSMP (n = 218), MMR deficiency (n = 191) was associated with poor disease-specific survival (p = 0.001). MMR deficiency was associated with an increased risk of cancer-related death when controlling for confounders (hazard ratio 2.0). In the absence of established clinicopathologic risk factors, MMR deficiency was invariably associated with an increased risk of cancer-related death in univariable analyses (hazard ratios ≥ 2.0). In contrast, outcomes for MMR deficient and NSMP subgroups did not differ when risk factors were present. Lymphatic dissemination was more common (p = 0.008) and the proportion of pelvic relapses was higher (p = 0.029) in the MMR deficient subgroup. Our findings emphasize the need for improved triage to adjuvant therapy and new therapeutic approaches in MMR deficient endometrial carcinomas.
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25
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Elez M. Mismatch Repair: From Preserving Genome Stability to Enabling Mutation Studies in Real-Time Single Cells. Cells 2021; 10:cells10061535. [PMID: 34207040 PMCID: PMC8235422 DOI: 10.3390/cells10061535] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 06/11/2021] [Accepted: 06/15/2021] [Indexed: 12/18/2022] Open
Abstract
Mismatch Repair (MMR) is an important and conserved keeper of the maintenance of genetic information. Miroslav Radman's contributions to the field of MMR are multiple and tremendous. One of the most notable was to provide, along with Bob Wagner and Matthew Meselson, the first direct evidence for the existence of the methyl-directed MMR. The purpose of this review is to outline several aspects and biological implications of MMR that his work has helped unveil, including the role of MMR during replication and recombination editing, and the current understanding of its mechanism. The review also summarizes recent discoveries related to the visualization of MMR components and discusses how it has helped shape our understanding of the coupling of mismatch recognition to replication. Finally, the author explains how visualization of MMR components has paved the way to the study of spontaneous mutations in living cells in real time.
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Affiliation(s)
- Marina Elez
- Micalis Institute, INRAE, AgroParisTech, Université Paris-Saclay, 78350 Jouy-en-Josas, France;
- Laboratoire Jean Perrin (LJP), Institut de Biologie Paris-Seine (IBPS), CNRS, Sorbonne Université, F-75005 Paris, France
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26
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Sychevskaya KA, Risinskaya NV, Kravchenko SK, Nikulina EE, Misyurina AE, Magomedova AU, Sudarikov AB. Pitfalls in mononucleotide microsatellite repeats instability assessing (MSI) in the patients with B-cell lymphomas. Klin Lab Diagn 2021; 66:181-186. [PMID: 33793119 DOI: 10.51620/0869-2084-2021-66-3-181-186] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Analysis of microsatellite instability (MSI) is a routine study in the diagnostics of solid malignancies. The standard for determining MSI is a pentaplex PCR panel of mononucleotide repeats: NR-21, NR-24, NR-27, BAT-25, BAT-26. The presence of MSI is established based on differences in the length of markers in the tumor tissue and in the control, but due to the quasimonomorphic nature of standard mononucleotide loci the use of a control sample is not necessary in the diagnosis of MSI-positive solid tumors. The significance of the MSI phenomenon in oncohematology has not been established. This paper presents the results of a study of MSI in B-cell lymphomas: follicular lymphoma (FL), diffuse large B-cell lymphoma (DLBCL), high-grade B-cell lymphoma (HGBL). We have shown that aberrations of mononucleotide markers occur in these diseases, but the nature of the changes does not correspond to the classical MSI in solid neoplasms. This fact requires further study of the pathogenesis of such genetic disorders. Due to the possibility of ambiguous interpretation of the results of the MSI study for previously uncharacterized diseases, strict compliance with the methodology of parallel analysis of the tumor tissue and the control sample is mandatory.
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27
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Loukovaara M, Pasanen A, Bützow R. Mismatch repair protein and MLH1 methylation status as predictors of response to adjuvant therapy in endometrial cancer. Cancer Med 2021; 10:1034-1042. [PMID: 33449452 PMCID: PMC7897956 DOI: 10.1002/cam4.3691] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 11/30/2020] [Accepted: 12/08/2020] [Indexed: 12/19/2022] Open
Abstract
BACKGROUND Mismatch repair (MMR) system has been implicated in the response of mammalian cells to ionizing radiation and DNA damaging agents. We investigated the value of the MMR system in predicting response to adjuvant therapy in endometrial cancer. METHODS This was a single institution retrospective study. MMR protein status of endometrial carcinomas was assessed by immunohistochemistry. MMR deficient (MMR-D) tumors were identified as MLH1 methylated or nonmethylated by methylation-specific multiplex ligation-dependent probe amplification. Tumors with abnormal p53 staining or polymerase ϵ exonuclease domain mutation were excluded from the MMR proficient subgroup, which was termed as "no specific molecular profile" (NSMP). Disease-specific survival analyses were adjusted for age, stage, histology and grade, depth of myometrial invasion, and lymphovascular space invasion. RESULTS A total of 505 patients were included in the study. Median follow-up time was 81 months (range 1-136). Whole pelvic radiotherapy (adjusted hazard ratio [HR] 0.092 vs. no adjuvant therapy) and chemotherapy combined with radiotherapy (adjusted HR 0.18) were associated with improved disease-specific survival in the NSMP subgroup (n = 218). In contrast, adjuvant therapies showed no effect on disease-specific survival in the full MMR-D cohort (n = 287) or in MLH1 methylated tumors (n = 154). Whole pelvic radiotherapy (adjusted HR 25 vs. no adjuvant therapy/vaginal brachytherapy) and chemotherapy combined with whole pelvic radiotherapy (adjusted HR 32) were associated with poor disease-specific survival in MMR-D nonmethylated tumors (n = 70). CONCLUSION MMR protein and MLH1 methylation status predict the response to adjuvant therapy in endometrial cancer. The MMR system could be utilized for selection of patients who most likely benefit from adjuvant therapy.
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Affiliation(s)
- Mikko Loukovaara
- Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Annukka Pasanen
- Department of Pathology, Faculty of Medicine, Helsinki University Hospital and Research Program in Applied Tumor Genomics, University of Helsinki, Helsinki, Finland
| | - Ralf Bützow
- Department of Obstetrics and Gynecology, Helsinki University Hospital and University of Helsinki, Helsinki, Finland.,Department of Pathology, Faculty of Medicine, Helsinki University Hospital and Research Program in Applied Tumor Genomics, University of Helsinki, Helsinki, Finland
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28
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Alternative DNA Structures In Vivo: Molecular Evidence and Remaining Questions. Microbiol Mol Biol Rev 2020; 85:85/1/e00110-20. [PMID: 33361270 DOI: 10.1128/mmbr.00110-20] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Duplex DNA naturally folds into a right-handed double helix in physiological conditions. Some sequences of unusual base composition may nevertheless form alternative structures, as was shown for many repeated sequences in vitro However, evidence for the formation of noncanonical structures in living cells is difficult to gather. It mainly relies on genetic assays demonstrating their function in vivo or through genetic instability reflecting particular properties of such structures. Efforts were made to reveal their existence directly in a living cell, mainly by generating antibodies specific to secondary structures or using chemical ligands selected for their affinity to these structures. Among secondary structure-forming DNAs are G-quadruplexes, human fragile sites containing minisatellites, AT-rich regions, inverted repeats able to form cruciform structures, hairpin-forming CAG/CTG triplet repeats, and triple helices formed by homopurine-homopyrimidine GAA/TTC trinucleotide repeats. Many of these alternative structures are involved in human pathologies, such as neurological or developmental disorders, as in the case of trinucleotide repeats, or cancers triggered by translocations linked to fragile sites. This review will discuss and highlight evidence supporting the formation of alternative DNA structures in vivo and will emphasize the role of the mismatch repair machinery in binding mispaired DNA duplexes, triggering genetic instability.
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29
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Chen Y, Geng A, Zhang W, Qian Z, Wan X, Jiang Y, Mao Z. Fight to the bitter end: DNA repair and aging. Ageing Res Rev 2020; 64:101154. [PMID: 32977059 DOI: 10.1016/j.arr.2020.101154] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/05/2020] [Accepted: 08/19/2020] [Indexed: 12/11/2022]
Abstract
DNA carries the genetic information that directs complex biological processes; thus, maintaining a stable genome is critical for individual growth and development and for human health. DNA repair is a fundamental and conserved mechanism responsible for mending damaged DNA and restoring genomic stability, while its deficiency is closely related to multiple human disorders. In recent years, remarkable progress has been made in the field of DNA repair and aging. Here, we will extensively discuss the relationship among DNA damage, DNA repair, aging and aging-associated diseases based on the latest research. In addition, the possible role of DNA repair in several potential rejuvenation strategies will be discussed. Finally, we will also review the emerging methods that may facilitate future research on DNA repair.
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30
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New developments in Huntington's disease and other triplet repeat diseases: DNA repair turns to the dark side. Neuronal Signal 2020; 4:NS20200010. [PMID: 33224521 PMCID: PMC7672267 DOI: 10.1042/ns20200010] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 10/28/2020] [Accepted: 10/30/2020] [Indexed: 02/08/2023] Open
Abstract
Huntington’s disease (HD) is a fatal, inherited neurodegenerative disease that causes neuronal death, particularly in medium spiny neurons. HD leads to serious and progressive motor, cognitive and psychiatric symptoms. Its genetic basis is an expansion of the CAG triplet repeat in the HTT gene, leading to extra glutamines in the huntingtin protein. HD is one of nine genetic diseases in this polyglutamine (polyQ) category, that also includes a number of inherited spinocerebellar ataxias (SCAs). Traditionally it has been assumed that HD age of onset and disease progression were solely the outcome of age-dependent exposure of neurons to toxic effects of the inherited mutant huntingtin protein. However, recent genome-wide association studies (GWAS) have revealed significant effects of genetic variants outside of HTT. Surprisingly, these variants turn out to be mostly in genes encoding DNA repair factors, suggesting that at least some disease modulation occurs at the level of the HTT DNA itself. These DNA repair proteins are known from model systems to promote ongoing somatic CAG repeat expansions in tissues affected by HD. Thus, for triplet repeats, some DNA repair proteins seem to abandon their normal genoprotective roles and, instead, drive expansions and accelerate disease. One attractive hypothesis—still to be proven rigorously—is that somatic HTT expansions augment the disease burden of the inherited allele. If so, therapeutic approaches that lower levels of huntingtin protein may need blending with additional therapies that reduce levels of somatic CAG repeat expansions to achieve maximal effect.
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HDAC3 deacetylates the DNA mismatch repair factor MutSβ to stimulate triplet repeat expansions. Proc Natl Acad Sci U S A 2020; 117:23597-23605. [PMID: 32900932 PMCID: PMC7519323 DOI: 10.1073/pnas.2013223117] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Trinucleotide repeat (TNR) expansions cause nearly 20 severe human neurological diseases which are currently untreatable. For some of these diseases, ongoing somatic expansions accelerate disease progression and may influence age of onset. This new knowledge emphasizes the importance of understanding the protein factors that drive expansions. Recent genetic evidence indicates that the mismatch repair factor MutSβ (Msh2-Msh3 complex) and the histone deacetylase HDAC3 function in the same pathway to drive triplet repeat expansions. Here we tested the hypothesis that HDAC3 deacetylates MutSβ and thereby activates it to drive expansions. The HDAC3-selective inhibitor RGFP966 was used to examine its biological and biochemical consequences in human tissue culture cells. HDAC3 inhibition efficiently suppresses repeat expansion without impeding canonical mismatch repair activity. Five key lysine residues in Msh3 are direct targets of HDAC3 deacetylation. In cells expressing Msh3 in which these lysine residues are mutated to arginine, the inhibitory effect of RGFP966 on expansions is largely bypassed, consistent with the direct deacetylation hypothesis. RGFP966 treatment does not alter MutSβ subunit abundance or complex formation but does partially control its subcellular localization. Deacetylation sites in Msh3 overlap a nuclear localization signal, and we show that localization of MutSβ is partially dependent on HDAC3 activity. Together, these results indicate that MutSβ is a key target of HDAC3 deacetylation and provide insights into an innovative regulatory mechanism for triplet repeat expansions. The results suggest expansion activity may be druggable and support HDAC3-selective inhibition as an attractive therapy in some triplet repeat expansion diseases.
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32
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Tsuruta N, Tsuchihashi K, Ohmura H, Yamaguchi K, Ito M, Ariyama H, Kusaba H, Akashi K, Baba E. RNA N6-methyladenosine demethylase FTO regulates PD-L1 expression in colon cancer cells. Biochem Biophys Res Commun 2020; 530:235-239. [PMID: 32828292 DOI: 10.1016/j.bbrc.2020.06.153] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2020] [Accepted: 06/27/2020] [Indexed: 01/26/2023]
Abstract
Fat mass and obesity-associated protein (FTO) is an enzyme that demethylates N6-methyladenosine (m6A), the most abundant RNA modifications in a cell. The upregulated expression of FTO promotes the progression of various types of cancer by modulating cell-intrinsic genes which relate to malignant potential. However, the impact of FTO on the expression of immune-checkpoint molecules in the tumor cells, which are important for immune escape, has not been well understood. We examined the relevance of FTO to programmed cell death-ligand 1 (PD-L1) expression in colon cancer cells. HCT-116 cells showed high expression of both FTO and PD-L1 proteins. The knockdown of FTO by small interfering RNA decreased mRNA and protein levels of PD-L1 in HCT-116 cells. To elucidate the underlying mechanism by which FTO regulates the expression of PD-L1, we depleted FTO in HCT-116 in the presence of IFN-γ, which is a major stimulus to upregulate PD-L1 expression. Depletion of FTO reduced PD-L1 expression in an IFN-γ signaling-independent manner. RNA immunoprecipitation assay revealed the m6A modification of the PD-L1 mRNA and the binding of FTO to the PD-L1 mRNA in HCT-116. Taken together, our results indicated that FTO could regulate PD-L1 expression in colon cancer cells and provides new insights into the regulation of PD-L1 expression by RNA modification.
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Affiliation(s)
- Nobuhiro Tsuruta
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Kenji Tsuchihashi
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hirofumi Ohmura
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Kyoko Yamaguchi
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Mamoru Ito
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hiroshi Ariyama
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Hitoshi Kusaba
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Koichi Akashi
- Department of Medicine and Biosystemic Science, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Eishi Baba
- Department of Oncology and Social Medicine, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.
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Ahmad-Nielsen SA, Bruun Nielsen MF, Mortensen MB, Detlefsen S. Frequency of mismatch repair deficiency in pancreatic ductal adenocarcinoma. Pathol Res Pract 2020; 216:152985. [PMID: 32360245 DOI: 10.1016/j.prp.2020.152985] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2020] [Revised: 04/13/2020] [Accepted: 04/15/2020] [Indexed: 12/18/2022]
Abstract
Pancreatic ductal adenocarcinoma (PDAC) has an ominous prognosis and there are only few treatment options. It is therefore crucial to investigate possible predictive markers that may improve the treatment of this disease. Mismatch repair (MMR) deficiency (d-MMR), meaning MMR protein loss (l-MMR) and/or microsatellite instability (MSI), is predictive of response to immunotherapy, but its frequency has to our knowledge not been elucidated in Scandinavian PDACs. Our aims were to examine the frequency of d-MMR in a Danish cohort of PDACs. We constructed multi-punch tissue microarrays (TMAs) using primary tumor tissue. Immunohistochemistry (IHC) for the DNA MMR proteins MLH1, MSH2, MSH6 and PMS2 was performed, and their expression was evaluated using a scoring system from 0 to 4. If the overall score was between 0-2 or if IHC was inconclusive for technical reasons, IHC on whole-tissue sections and MSI using PCR was performed. A final score of 0, 1-2 or 3-4 defined the tumor as l-MMR, MMR reduced (r-MMR) or MMR proficient. In total, 4/164 (2.4 %), 2/164 (1.2 %) and 3/164 (1.8 %) were l-MMR, r-MMR, or inconclusive based on IHC. MSI testing of these specimens showed that two of the four l-MMR tumors were MSI-high, while the remaining cases were microsatellite stable (MSS). In conclusion, in this study of Danish PDACss, d-MMR was found in a small proportion of the tumors. For these patients, individualized treatment using immunotherapy could be considered.
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Affiliation(s)
- Soz Abdulrahman Ahmad-Nielsen
- Department of Pathology, Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark
| | | | - Michael Bau Mortensen
- Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark; HPB Section, Department of Surgery, Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark
| | - Sönke Detlefsen
- Department of Pathology, Odense Pancreas Center (OPAC), Odense University Hospital, Odense, Denmark; Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense, Denmark.
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34
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Sahin IH, Kane SR, Brutcher E, Guadagno J, Smith KE, Wu C, Lesinski GB, Gunthel CJ, El-Rayes BF. Safety and Efficacy of Immune Checkpoint Inhibitors in Patients With Cancer Living With HIV: A Perspective on Recent Progress and Future Needs. JCO Oncol Pract 2020; 16:319-325. [PMID: 32160138 DOI: 10.1200/jop.19.00754] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
Recent studies have identified durable responses with the use of immune checkpoint inhibitors in patients with mismatch repair-deficient (MMR-D)/microsatellite instability-high (MSI-H) metastatic colorectal cancer (CRC). The dramatic improvement in clinical outcomes led to the US Food and Drug Administration approval of pembrolizumab, nivolumab, and nivolumab in combination with ipilimumab in metastatic patients with MSI-H/MMR-D CRC who previously experienced progression on cytotoxic therapies. In the clinical trials investigating these agents, HIV-seropositive patients were not included and therefore the clinical efficacy of these agents in patients with metastatic MSI-H/MMR-D CRC living with HIV is unclear. On the basis of growing evidence, immune checkpoint blockade therapies seem to be a safe approach in patients with well-controlled HIV infection. Research on immunotherapeutic approaches in patients living with HIV and cancer is an area of unmet medical need that can be addressed by clinical trial designs that are inclusive of patients with well-controlled seropositive HIV and trials that specifically evaluate immune therapies in patients living with HIV.
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Affiliation(s)
| | - Sujata R Kane
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Edith Brutcher
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Jessica Guadagno
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Katherine E Smith
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Christina Wu
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Gregory B Lesinski
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Clifford J Gunthel
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
| | - Bassel F El-Rayes
- Emory University School of Medicine, Winship Cancer Institute, Atlanta, GA
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Khand FM, Yao DW, Hao P, Wu XQ, Kamboh AA, Yang DJ. Microsatellite Instability and MMR Genes Abnormalities in Canine Mammary Gland Tumors. Diagnostics (Basel) 2020; 10:diagnostics10020104. [PMID: 32075116 PMCID: PMC7169452 DOI: 10.3390/diagnostics10020104] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 02/11/2020] [Accepted: 02/12/2020] [Indexed: 02/03/2023] Open
Abstract
Early diagnosis of mammary gland tumors is a challenging task in animals, especially in unspayed dogs. Hence, this study investigated the role of microsatellite instability (MSI), MMR gene mRNA transcript levels and SNPs of MMR genes in canine mammary gland tumors (CMT). A total of 77 microsatellite (MS) markers in 23 primary CMT were selected from four breeds of dogs. The results revealed that 11 out of 77 MS markers were unstable and showed MSI in all the tumors (at least at one locus), while the other markers were stable. Compared to the other markers, the ABC9TETRA, MEPIA, 9A5, SCNA11 and FJL25 markers showed higher frequencies of instability. All CMT demonstrated MSI, with eight tumors presenting MSI-H. The RT-qPCR results revealed significant upregulation of the mRNA levels of cMSH3, cMLH1, and cPMSI, but downregulation of cMSH2 compared to the levels in the control group. Moreover, single nucleotide polymorphisms (SNPs) were observed in the cMSH2 gene in four exons, i.e., 2, 6, 15, and 16. In conclusion, MSI, overexpression of MMR genes and SNPs in the MMR gene are associated with CMT and could be served as diagnostic biomarkers for CMT in the future.
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Affiliation(s)
- Faiz Muhammad Khand
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; (F.M.K.); (D.-W.Y.); (P.H.); (X.-Q.W.); (A.A.K.)
| | - Da-Wei Yao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; (F.M.K.); (D.-W.Y.); (P.H.); (X.-Q.W.); (A.A.K.)
| | - Pan Hao
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; (F.M.K.); (D.-W.Y.); (P.H.); (X.-Q.W.); (A.A.K.)
| | - Xin-Qi Wu
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; (F.M.K.); (D.-W.Y.); (P.H.); (X.-Q.W.); (A.A.K.)
| | - Asghar Ali Kamboh
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; (F.M.K.); (D.-W.Y.); (P.H.); (X.-Q.W.); (A.A.K.)
| | - De-Ji Yang
- College of Veterinary Medicine, Nanjing Agricultural University, Nanjing, Jiangsu 210095, China; (F.M.K.); (D.-W.Y.); (P.H.); (X.-Q.W.); (A.A.K.)
- Correspondence: ; Tel.: +86-025-843-95505
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36
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Rikitake M, Fujikane R, Obayashi Y, Oka K, Ozaki M, Hidaka M. MLH1-mediated recruitment of FAN1 to chromatin for the induction of apoptosis triggered by O 6 -methylguanine. Genes Cells 2020; 25:175-186. [PMID: 31955481 DOI: 10.1111/gtc.12748] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2020] [Revised: 01/10/2020] [Accepted: 01/10/2020] [Indexed: 01/03/2023]
Abstract
O6 -Methylguanines (O6 -meG), which are produced in DNA by the action of alkylating agents, are mutagenic and cytotoxic, and induce apoptosis in a mismatch repair (MMR) protein-dependent manner. To understand the molecular mechanism of O6 -meG-induced apoptosis, we performed functional analyses of FANCD2 and FANCI-associated nuclease 1 (FAN1), which was identified as an interacting partner of MLH1. Immunoprecipitation analyses showed that FAN1 interacted with both MLH1 and MSH2 after treatment with N-methyl-N-nitrosourea (MNU), indicating the formation of a FAN1-MMR complex. In comparison with control cells, FAN1-knockdown cells were more resistant to MNU, and the appearances of a sub-G1 population and caspase-9 activation were suppressed. FAN1 formed nuclear foci in an MLH1-dependent manner after MNU treatment, and some were colocalized with both MLH1 foci and single-stranded DNA (ssDNA) created at damaged sites. Under the same condition, FANCD2 also formed nuclear foci, although it was dispensable for the formation of FAN1 foci and ssDNA. MNU-induced formation of ssDNA was dramatically suppressed in FAN1-knockdown cells. We therefore propose that FAN1 is loaded on chromatin through the interaction with MLH1 and produces ssDNA by its exonuclease activity, which contributes to the activation of the DNA damage response followed by the induction of apoptosis triggered by O6 -meG.
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Affiliation(s)
- Mihoko Rikitake
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan.,Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan
| | - Ryosuke Fujikane
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan.,Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
| | - Yuko Obayashi
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan.,Department of Oral and Maxillofacial Surgery, Fukuoka Dental College, Fukuoka, Japan
| | - Kyoko Oka
- Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan
| | - Masao Ozaki
- Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka, Japan
| | - Masumi Hidaka
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka, Japan.,Oral Medicine Research Center, Fukuoka Dental College, Fukuoka, Japan
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37
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Huang Y, Li GM. DNA mismatch repair in the context of chromatin. Cell Biosci 2020; 10:10. [PMID: 32025281 PMCID: PMC6996186 DOI: 10.1186/s13578-020-0379-7] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Accepted: 01/24/2020] [Indexed: 12/11/2022] Open
Abstract
DNA mismatch repair (MMR) maintains replication fidelity by correcting mispaired nucleotides incorporated by DNA polymerases. Defects in MMR lead to cancers characterized by microsatellite instability. Recently, chromatin mechanisms that regulate MMR have been discovered, which sheds new light on MMR deficiency and its role in tumorigenesis. This review summarizes these chromatin-level mechanisms that regulate MMR and their implications for tumor development.
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Affiliation(s)
- Yaping Huang
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390 USA
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38
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Human MutLγ, the MLH1-MLH3 heterodimer, is an endonuclease that promotes DNA expansion. Proc Natl Acad Sci U S A 2020; 117:3535-3542. [PMID: 32015124 PMCID: PMC7035508 DOI: 10.1073/pnas.1914718117] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
MutL proteins are ubiquitous and play important roles in DNA metabolism. MutLγ (MLH1-MLH3 heterodimer) is a poorly understood member of the eukaryotic family of MutL proteins that has been implicated in triplet repeat expansion, but its action in this deleterious process has remained unknown. In humans, triplet repeat expansion is the molecular basis for ∼40 neurological disorders. In addition to MutLγ, triplet repeat expansion involves the mismatch recognition factor MutSβ (MSH2-MSH3 heterodimer). We show here that human MutLγ is an endonuclease that nicks DNA. Strikingly, incision of covalently closed, relaxed loop-containing DNA by human MutLγ is promoted by MutSβ and targeted to the strand opposite the loop. The resulting strand break licenses downstream events that lead to a DNA expansion event in human cell extracts. Our data imply that the mammalian MutLγ is a unique endonuclease that can initiate triplet repeat DNA expansions.
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39
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Brown LC, Armstrong AJ. Has Mismatch Repair–Deficient Cancer Met Its MATCH? J Clin Oncol 2020; 38:183-187. [DOI: 10.1200/jco.19.02860] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Affiliation(s)
- Landon C. Brown
- Duke Cancer Institute, Center for Prostate and Urologic Cancers, Duke University, Durham, NC
| | - Andrew J. Armstrong
- Duke Cancer Institute, Center for Prostate and Urologic Cancers, Duke University, Durham, NC
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40
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SMARCAD1-mediated recruitment of the DNA mismatch repair protein MutLα to MutSα on damaged chromatin induces apoptosis in human cells. J Biol Chem 2020. [DOI: 10.1016/s0021-9258(17)49915-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
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41
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Takeishi Y, Fujikane R, Rikitake M, Obayashi Y, Sekiguchi M, Hidaka M. SMARCAD1-mediated recruitment of the DNA mismatch repair protein MutLα to MutSα on damaged chromatin induces apoptosis in human cells. J Biol Chem 2019; 295:1056-1065. [PMID: 31843968 DOI: 10.1074/jbc.ra119.008854] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2019] [Revised: 12/12/2019] [Indexed: 12/12/2022] Open
Abstract
The mismatch repair (MMR) complex is composed of MutSα (MSH2-MSH6) and MutLα (MLH1-PMS2) and specifically recognizes mismatched bases during DNA replication. O 6-Methylguanine is produced by treatment with alkylating agents, such as N-methyl-N-nitrosourea (MNU), and during DNA replication forms a DNA mismatch (i.e. an O 6-methylguanine/thymine pair) and induces a G/C to A/T transition mutation. To prevent this outcome, cells carrying this DNA mismatch are eliminated by MMR-dependent apoptosis, but the underlying molecular mechanism is unclear. In this study, we provide evidence that the chromatin-regulatory and ATP-dependent nucleosome-remodeling protein SMARCAD1 is involved in the induction of MMR-dependent apoptosis in human cells. Unlike control cells, SMARCAD1-knockout cells (ΔSMARCAD1) were MNU-resistant, and the appearance of a sub-G1 population and caspase-9 activation were significantly suppressed in the ΔSMARCAD1 cells. Furthermore, the MNU-induced mutation frequencies were increased in these cells. Immunoprecipitation analyses revealed that the recruitment of MutLα to chromatin-bound MutSα, observed in SMARCAD1-proficient cells, is suppressed in ΔSMARCAD1 cells. Of note, the effect of SMARCAD1 on the recruitment of MutLα exclusively depended on the ATPase activity of the protein. On the basis of these findings, we propose that SMARCAD1 induces apoptosis via its chromatin-remodeling activity, which helps recruit MutLα to MutSα on damaged chromatin.
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Affiliation(s)
- Yukimasa Takeishi
- Advanced Science Research Center, Fukuoka Dental College, Fukuoka 814-0193, Japan
| | - Ryosuke Fujikane
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka 814-0193, Japan
| | - Mihoko Rikitake
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka 814-0193, Japan.,Department of Oral Growth and Development, Fukuoka Dental College, Fukuoka 814-0193, Japan
| | - Yuko Obayashi
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka 814-0193, Japan.,Department of Oral and Maxillofacial Surgery, Fukuoka Dental College, Fukuoka 814-0193, Japan
| | - Mutsuo Sekiguchi
- Advanced Science Research Center, Fukuoka Dental College, Fukuoka 814-0193, Japan
| | - Masumi Hidaka
- Department of Physiological Science and Molecular Biology, Fukuoka Dental College, Fukuoka 814-0193, Japan
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42
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Houlleberghs H, Dekker M, Lusseveld J, Pieters W, van Ravesteyn T, Verhoef S, Hofstra RMW, Te Riele H. Three-step site-directed mutagenesis screen identifies pathogenic MLH1 variants associated with Lynch syndrome. J Med Genet 2019; 57:308-315. [PMID: 31784484 DOI: 10.1136/jmedgenet-2019-106520] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 10/12/2019] [Accepted: 10/16/2019] [Indexed: 12/30/2022]
Abstract
BACKGROUND Inactivating mutations in the MLH1 DNA mismatch repair (MMR) gene underlie 42% of Lynch syndrome (LS) cases. LS is a cancer predisposition causing early onset colorectal and endometrial cancer. Nonsense and frameshift alterations unambiguously cause LS. The phenotype of missense mutations that only alter a single amino acid is often unclear. These variants of uncertain significance (VUS) hinder LS diagnosis and family screening and therefore functional tests are urgently needed. We developed a functional test for MLH1 VUS termed 'oligonucleotide-directed mutation screening' (ODMS). METHODS The MLH1 variant was introduced by oligonucleotide-directed gene modification in mouse embryonic stem cells that were subsequently exposed to the guanine analogue 6-thioguanine to determine whether the variant abrogated MMR. RESUTS In a proof-of-principle analysis, we demonstrate that ODMS can distinguish pathogenic and non-pathogenic MLH1 variants with a sensitivity of >95% and a specificity of >91%. We subsequently applied the screen to 51 MLH1 VUS and identified 31 pathogenic variants. CONCLUSION ODMS is a reliable tool to identify pathogenic MLH1 variants. Implementation in clinical diagnostics will improve clinical care of patients with suspected LS and their relatives.
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Affiliation(s)
- Hellen Houlleberghs
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Marleen Dekker
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Jarnick Lusseveld
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Wietske Pieters
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Thomas van Ravesteyn
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
| | - Senno Verhoef
- Department of Clinical Genetics, Leiden University Medical Center, Leiden, The Netherlands
| | - Robert M W Hofstra
- Department of Clinical Genetics, Erasmus MC, Erasmus University Rotterdam, Rotterdam, The Netherlands
| | - Hein Te Riele
- Division of Tumor Biology and Immunology, The Netherlands Cancer Institute, Amsterdam, The Netherlands
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43
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Li H, Wang X, Zhao H, Wang F, Bao Y, Guo J, Chang S, Wu L, Cheng H, Chen S, Zou J, Cui X, Niswander L, Finnell RH, Wang H, Zhang T. Low folate concentration impacts mismatch repair deficiency in neural tube defects. Epigenomics 2019; 12:5-18. [PMID: 31769301 DOI: 10.2217/epi-2019-0279] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Aim: To know the cause of sequence variants in neural tube defect (NTD). Materials & methods: We sequenced genes implicated in neural tube closure (NTC) in a Chinese cohort and elucidated the molecular mechanism-driving mutations. Results: In NTD cases, an increase in specific variants was identified, potentially deleterious rare variants harbored in H3K36me3 occupancy regions that recruits mismatch repair (MMR) machinery. Lower folate concentrations in local brain tissues were also observed. In neuroectoderm cells, folic acid insufficiency attenuated association of Msh6 to H3K36me3, and reduced bindings to NTC genes. Rare variants in human NTDs were featured by MMR deficiency and more severe microsatellite instability. Conclusion: Our work suggests a mechanistic link between folate insufficiency and MMR deficiency that correlates with an increase of rare variants in NTC genes.
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Affiliation(s)
- Huili Li
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China.,Department of Molecular, Cellular & Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Xiaolei Wang
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Huizhi Zhao
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Fang Wang
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Yihua Bao
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Jin Guo
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Shaoyan Chang
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Lihua Wu
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Haiqin Cheng
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Shuyuan Chen
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Jizhen Zou
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Xiaodai Cui
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
| | - Lee Niswander
- Department of Molecular, Cellular & Developmental Biology, University of Colorado at Boulder, Boulder, CO 80309, USA
| | - Richard H Finnell
- Obstetrics & Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction & Development, Fudan University, Shanghai 200011, China.,Center for Precision Environmental Health, Baylor College of Medicine, Houston, TX 77030, USA
| | - Hongyan Wang
- Obstetrics & Gynecology Hospital, State Key Laboratory of Genetic Engineering at School of Life Sciences, Institute of Reproduction & Development, Fudan University, Shanghai 200011, China.,Key Laboratory of Reproduction Regulation of NPFPC, Collaborative Innovation Center of Genetics & Development, Fudan University, Shanghai 200032, China.,Children's Hospital, Fudan University, Shanghai 201102, China
| | - Ting Zhang
- Beijing Municipal Key Laboratory of Child Development & Nutriomics, Capital Institute of Pediatrics, Beijing 100020, China
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44
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Grazioso TP, Brandt M, Djouder N. Diet, Microbiota, and Colorectal Cancer. iScience 2019; 21:168-187. [PMID: 31669832 PMCID: PMC6889474 DOI: 10.1016/j.isci.2019.10.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 07/03/2019] [Accepted: 10/02/2019] [Indexed: 02/07/2023] Open
Abstract
The intestinal epithelium is a very dynamic tissue under a high regenerative pressure, which makes it susceptible to malignant transformation. Proper integration of various cell signaling pathways and a balanced cross talk between different cell types composing the organ are required to maintain intestinal homeostasis. Dysregulation of this balance can lead to colorectal cancer (CRC). Here, we review important insights into molecular and cellular mechanisms of CRC. We discuss how perturbation in complex regulatory networks, including the Wnt, Notch, BMP, and Hedgehog pathways; and how variations in inflammatory signaling, nutrients, and microbiota can affect intestinal homeostasis contributing to the malignant transformation of intestinal cells.
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Affiliation(s)
- Tatiana P Grazioso
- Molecular Oncology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Marta Brandt
- Molecular Oncology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain
| | - Nabil Djouder
- Molecular Oncology Programme, Growth Factors, Nutrients and Cancer Group, Centro Nacional Investigaciones Oncológicas, CNIO, Madrid 28029, Spain.
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45
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Russo M, Crisafulli G, Sogari A, Reilly NM, Arena S, Lamba S, Bartolini A, Amodio V, Magrì A, Novara L, Sarotto I, Nagel ZD, Piett CG, Amatu A, Sartore-Bianchi A, Siena S, Bertotti A, Trusolino L, Corigliano M, Gherardi M, Lagomarsino MC, Di Nicolantonio F, Bardelli A. Adaptive mutability of colorectal cancers in response to targeted therapies. Science 2019; 366:1473-1480. [PMID: 31699882 DOI: 10.1126/science.aav4474] [Citation(s) in RCA: 255] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 07/24/2019] [Accepted: 10/26/2019] [Indexed: 12/13/2022]
Abstract
The emergence of drug resistance limits the efficacy of targeted therapies in human tumors. The prevalent view is that resistance is a fait accompli: when treatment is initiated, cancers already contain drug-resistant mutant cells. Bacteria exposed to antibiotics transiently increase their mutation rates (adaptive mutability), thus improving the likelihood of survival. We investigated whether human colorectal cancer (CRC) cells likewise exploit adaptive mutability to evade therapeutic pressure. We found that epidermal growth factor receptor (EGFR)/BRAF inhibition down-regulates mismatch repair (MMR) and homologous recombination DNA-repair genes and concomitantly up-regulates error-prone polymerases in drug-tolerant (persister) cells. MMR proteins were also down-regulated in patient-derived xenografts and tumor specimens during therapy. EGFR/BRAF inhibition induced DNA damage, increased mutability, and triggered microsatellite instability. Thus, like unicellular organisms, tumor cells evade therapeutic pressures by enhancing mutability.
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Affiliation(s)
- Mariangela Russo
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy. .,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Giovanni Crisafulli
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Alberto Sogari
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Nicole M Reilly
- Fondazione Piemontese per la Ricerca sul Cancro ONLUS, Candiolo (TO) 10060, Italy
| | - Sabrina Arena
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Simona Lamba
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy
| | - Alice Bartolini
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy
| | - Vito Amodio
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Alessandro Magrì
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Luca Novara
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy
| | - Ivana Sarotto
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy
| | - Zachary D Nagel
- Department of Environmental Health, JBL Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Cortt G Piett
- Department of Environmental Health, JBL Center for Radiation Sciences, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Alessio Amatu
- Niguarda Cancer Center, Grande Ospedale Metropolitano Niguarda, 20162 Milan, Italy.,Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, 20133 Milan, Italy
| | - Andrea Sartore-Bianchi
- Niguarda Cancer Center, Grande Ospedale Metropolitano Niguarda, 20162 Milan, Italy.,Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, 20133 Milan, Italy
| | - Salvatore Siena
- Niguarda Cancer Center, Grande Ospedale Metropolitano Niguarda, 20162 Milan, Italy.,Department of Oncology and Hemato-Oncology, Università degli Studi di Milano, 20133 Milan, Italy
| | - Andrea Bertotti
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Livio Trusolino
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Mattia Corigliano
- IFOM-FIRC Institute of Molecular Oncology, 20139 Milan, Italy.,Department of Physics, Università degli Studi di Milano, and I.N.F.N., 20133 Milan, Italy
| | - Marco Gherardi
- IFOM-FIRC Institute of Molecular Oncology, 20139 Milan, Italy.,Department of Physics, Università degli Studi di Milano, and I.N.F.N., 20133 Milan, Italy
| | - Marco Cosentino Lagomarsino
- IFOM-FIRC Institute of Molecular Oncology, 20139 Milan, Italy.,Department of Physics, Università degli Studi di Milano, and I.N.F.N., 20133 Milan, Italy
| | - Federica Di Nicolantonio
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy.,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
| | - Alberto Bardelli
- Candiolo Cancer Institute, FPO-IRCCS, Candiolo (TO) 10060, Italy. .,Department of Oncology, University of Torino, Candiolo (TO) 10060, Italy
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46
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Goellner EM. Chromatin remodeling and mismatch repair: Access and excision. DNA Repair (Amst) 2019; 85:102733. [PMID: 31698199 DOI: 10.1016/j.dnarep.2019.102733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2019] [Revised: 09/06/2019] [Accepted: 10/09/2019] [Indexed: 01/03/2023]
Abstract
DNA mismatch repair (MMR) increases replication fidelity and genome stability by correcting DNA polymerase errors that remain after replication. Defects in MMR result in the accumulation of mutations and lead to human tumor development. Germline mutations in MMR cause the hereditary cancer syndrome, Lynch syndrome. After replication, DNA is reorganized into its chromatin structure and wrapped around histone octamers. DNA MMR is thought to be less efficient in recognizing and repairing mispairs packaged in chromatin, in which case MMR must either compete for access to naked DNA before histone deposition or actively move nucleosomes to access the mispair. This article reviews studies into the mechanistic and physical interactions between MMR and various chromatin-associated factors, including the histone deposition complex CAF1. Recent Xenopus and Saccharomyces cerevisiae studies describe a physical interaction between Msh2 and chromatin-remodeling ATPase Fun30/SMARCAD1, with potential mechanistic roles for SMARCAD1 in moving histones for both mispair access and excision tract elongation. The RSC complex, another histone remodeling complex, also potentially influences excision tract length. Deletion mutations of RSC2 point to mechanistic interactions with the MMR pathways. Together, these studies paint a picture of complex interactions between MMR and the chromatin environment that will require numerous additional genetic, biochemical, and cell biology experiments to fully understand. Understanding how these pathways interconnect is essential in fully understanding eukaryotic MMR and has numerous implications in human tumor formation and treatment.
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Affiliation(s)
- Eva M Goellner
- Department of Toxicology and Cancer Biology, Markey Cancer Center, University of Kentucky College of Medicine, Lexington, KY, 40536, USA.
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47
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Hashmi AA, Mudassir G, Hashmi RN, Irfan M, Asif H, Khan EY, Abu Bakar SM, Faridi N. Microsatellite Instability in Endometrial Carcinoma by Immunohistochemistry, Association with Clinical and Histopathologic Parameters. Asian Pac J Cancer Prev 2019; 20:2601-2606. [PMID: 31554352 PMCID: PMC6976824 DOI: 10.31557/apjcp.2019.20.9.2601] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2018] [Indexed: 11/25/2022] Open
Abstract
Objective: We aimed to investigate the frequency of microsatellite instability (MSI) in endometrial carcinoma in our
population and its association with clinico-pathologic features. Methods: A total of 126 cases of primary endometrial
carcinoma were included in the study that underwent surgical resections. All slides of these cases were reviewed and
representative paraffin fixed tissue blocks were selected for MLH1, MSH2, MSH6 and PMS2 IHC staining. IHC
expression was categorized into five groups: no loss of expression; loss of expression of all four antibodies; combined
loss of MLH1/PMS2; combined loss of MSH2/MSH6; and isolated loss of MLH1. Pathological records of all cases
were retrieved from patient files. Result: Abnormal expression of MSI was noted in 56 cases (44.4%) among which
16 cases showed loss of nuclear expression of all markers, 34 cases showed loss of MLH1/PMS2 expression, 4 cases
showed loss of MSH2/MSH6 while only 2 cases revealed isolated loss of MLH. Personal and family history suggestive
of inherited cancer susceptibility was revealed in 11 cases most of which were associated with MSH2/MSH6 loss.
Significant association of MSI expression was found with tumor stage and personal/family history of endometrial/
colon cancer. Conclusion: A high frequency of endometrioid cancers in our study showed abnormal expression of
MSI markers, most of which depicted MLH1/PMS2 loss and were not associated with inherited cancer susceptibility.
On the other hand, a minority of cases showed loss of all MSI markers or MSH2/MSH6 loss and were significantly
associated with family/personal history of cancer. Therefore, we suggest that epigenetic changes in MLH1 locus may
be a predominant pathway of tumorigenesis in our population rather than inherited mutation of MSI genes; however
more large scale studies with genetic testing are required to validate this observation.
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Affiliation(s)
- Atif Ali Hashmi
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
| | - Ghazala Mudassir
- Department of Pathology, Shifa College of Medicine, Islamabad, Pakistan
| | | | - Muhammad Irfan
- Department of Statistics, Liaquat National Hospital and Medical College, Karachi, Pakistan
| | - Huda Asif
- Medical Student, CMH Institute of Medical Sciences, Multan, Pakistan
| | - Erum Yousuf Khan
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
| | - Syed Muhammad Abu Bakar
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
| | - Naveen Faridi
- Department of Histopathology, Liaquat National Hospital and Medical College, Karachi, Pakistan.
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48
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Lian J, Xia L, Chen Y, Zheng J, Ma K, Luo L, Ye F. Aldolase B impairs DNA mismatch repair and induces apoptosis in colon adenocarcinoma. Pathol Res Pract 2019; 215:152597. [PMID: 31564566 DOI: 10.1016/j.prp.2019.152597] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/22/2019] [Revised: 08/07/2019] [Accepted: 08/16/2019] [Indexed: 12/31/2022]
Abstract
Evidence suggests that DNA repair capacity manifested by intact functional base excision repair and mismatch repair (MMR) pathways is related to the prognosis of multiple cancer types. Aldolase B (ALDOB) is well known for its role in metabolism and glycolysis. The expression of ALDOB in colon adenocarcinoma and the relationship between its expression and colon adenocarcinoma prognosis remain controversial; in addition, the potential role of ALDOB in DNA MMR has not yet been reported. In this study, we identified a cluster of DNA repair-related proteins that interact with ALDOB in the colon adenocarcinoma cell line HCT116. Expression analysis of colon adenocarcinoma data from the Cancer Genome Atlas (TCGA-COAD data, n = 551) indicated that ALDOB mRNA expression was significantly higher in specimens with microsatellite instability (MSI) than in specimens with microsatellite stability (MSS). Regarding prognosis, colon adenocarcinoma patients with high ALDOB mRNA expression had longer overall survival (OS). Higher expression of ALDOB protein was significantly correlated with MMR deficiency (d-MMR) in formalin-fixed paraffin-embedded (FFPE) patient specimens. The expression of ALDOB was significantly elevated in colon adenocarcinoma cell lines. Further evidence indicated that rather than affecting proliferation, ALDOB overexpression induced the functional loss of MMR proteins and in turn caused irreversible DNA damage via disrupting EZH2-Rad51 expression and then caused apoptosis by ERK inactivation. Overall, our study demonstrates that high ALDOB expression impairs DNA MMR and induces apoptosis in colon adenocarcinoma. ALDOB may be a new biomarker associated with d-MMR and an independent prognostic factor for colon adenocarcinoma.
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Affiliation(s)
- Jiabian Lian
- Laboratory of Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Clinical Medical, Fujian Medical University, Fuzhou, China; Department of Cancer Prevention Diagnosis and Treatment, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Lu Xia
- Laboratory of Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Clinical Medical, Fujian Medical University, Fuzhou, China; Department of Cancer Prevention Diagnosis and Treatment, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Yixing Chen
- Laboratory of Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Clinical Medical, Fujian Medical University, Fuzhou, China
| | - Jiani Zheng
- Department of Medical Oncology, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Clinical Medical, Fujian Medical University, Fuzhou, China; Department of Cancer Prevention Diagnosis and Treatment, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Ke Ma
- Department of Gastrointestinal Surgery, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China
| | - Lingtao Luo
- Department of Gastrointestinal Surgery, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Clinical Medical, Fujian Medical University, Fuzhou, China; Department of Cancer Prevention Diagnosis and Treatment, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China.
| | - Feng Ye
- Department of Medical Oncology, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China; Department of Clinical Medical, Fujian Medical University, Fuzhou, China; Department of Cancer Prevention Diagnosis and Treatment, Cancer Hospital, The First Affiliated Hospital of Xiamen University, Xiamen, China.
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49
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Tiwari V, Wilson DM. DNA Damage and Associated DNA Repair Defects in Disease and Premature Aging. Am J Hum Genet 2019; 105:237-257. [PMID: 31374202 PMCID: PMC6693886 DOI: 10.1016/j.ajhg.2019.06.005] [Citation(s) in RCA: 125] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2019] [Accepted: 06/05/2019] [Indexed: 12/14/2022] Open
Abstract
Genetic information is constantly being attacked by intrinsic and extrinsic damaging agents, such as reactive oxygen species, atmospheric radiation, environmental chemicals, and chemotherapeutics. If DNA modifications persist, they can adversely affect the polymerization of DNA or RNA, leading to replication fork collapse or transcription arrest, or can serve as mutagenic templates during nucleic acid synthesis reactions. To combat the deleterious consequences of DNA damage, organisms have developed complex repair networks that remove chemical modifications or aberrant base arrangements and restore the genome to its original state. Not surprisingly, inherited or sporadic defects in DNA repair mechanisms can give rise to cellular outcomes that underlie disease and aging, such as transformation, apoptosis, and senescence. In the review here, we discuss several genetic disorders linked to DNA repair defects, attempting to draw correlations between the nature of the accumulating DNA damage and the pathological endpoints, namely cancer, neurological disease, and premature aging.
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Affiliation(s)
- Vinod Tiwari
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA.
| | - David M Wilson
- Laboratory of Molecular Gerontology, National Institute on Aging, Intramural Research Program, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Baltimore, MD 21224, USA.
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50
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Henriksen A, Dyhl-Polk A, Chen I, Nielsen D. Checkpoint inhibitors in pancreatic cancer. Cancer Treat Rev 2019; 78:17-30. [DOI: 10.1016/j.ctrv.2019.06.005] [Citation(s) in RCA: 134] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/24/2019] [Accepted: 06/26/2019] [Indexed: 12/18/2022]
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