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Liao L, Deng L, Zhang Y, Yang S, Andriani L, Hu S, Zhang F, Shao Z, Li D. C9orf142 transcriptionally activates MTBP to drive progression and resistance to CDK4/6 inhibitor in triple-negative breast cancer. Clin Transl Med 2023; 13:e1480. [PMID: 38009308 PMCID: PMC10679971 DOI: 10.1002/ctm2.1480] [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: 05/05/2023] [Revised: 10/28/2023] [Accepted: 11/04/2023] [Indexed: 11/28/2023] Open
Abstract
BACKGROUND Triple-negative breast cancer (TNBC) presents the most challenging subtype of all breast cancers because of its aggressive clinical phenotypes and absence of viable therapy targets. In order to identify effective molecular targets for treating patients with TNBC, we conducted an integration analysis of our recently published TNBC dataset of quantitative proteomics and RNA-Sequencing, and found the abnormal upregulation of chromosome 9 open reading frame 142 (C9orf142) in TNBC. However, the functional roles of C9orf142 in TNBC are unclear. METHODS In vitro and in vivo functional experiments were performed to assess potential roles of C9orf142 in TNBC. Immunoblotting, real-time quantitative polymerase chain reaction (RT-qPCR), and immunofluorescent staining were used to investigate the expression levels of C9orf142 and its downstream molecules. The molecular mechanisms underlying C9orf142-regulated mouse double minute 2 (MDM2)-binding protein (MTBP) were determined by chromatin immunoprecipitation (ChIP) and dual-luciferase reporter assays. RESULTS In TNBC tissues and metastatic lymph nodes, we observed that C9orf142 exhibited abnormal up-regulation, and its elevated expression was indicative of unfavorable prognosis for TNBC patients. Both in vitro and in vivo functional experiments demonstrated that C9orf142 accelerated TNBC growth and metastasis. Further mechanism exploration revealed that C9orf142 transcriptionally activated MTBP, thereby regulating its downstream MDM2/p53/p21 signaling axis and the transition of cell cycle from G1 to S phase. Functional rescue experiment demonstrated that knockdown of MTBP attenuated C9orf142-mediated tumour growth and metastasis. Furthermore, depletion of C9orf142 remarkably increased the responsiveness of TNBC cells to CDK4/6 inhibitor abemaciclib. CONCLUSIONS Together, these findings unveil a previously unrecognized effect of C9orf142 in TNBC progression and responsiveness to CDK4/6 inhibitor, and emphasize C9orf142 as a promising intervention target for TNBC treatment.
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Affiliation(s)
- Li Liao
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Cancer Institute, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
| | - Ling Deng
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
| | - Yin‐Ling Zhang
- Cancer Institute, Shanghai Medical CollegeFudan UniversityShanghaiChina
| | - Shao‐Ying Yang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Cancer Institute, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
| | - Lisa Andriani
- Department of Breast Surgery, Fudan University Shanghai Cancer CenterFudan UniversityShanghaiChina
| | - Shu‐Yuan Hu
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
| | - Fang‐Lin Zhang
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Cancer Institute, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
| | - Zhi‐Min Shao
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Cancer Institute, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Breast Surgery, Fudan University Shanghai Cancer CenterFudan UniversityShanghaiChina
- Shanghai Key Laboratory of Breast Cancer, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Key Laboratory of Radiation Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
| | - Da‐Qiang Li
- Fudan University Shanghai Cancer Center and Institutes of Biomedical SciencesFudan UniversityShanghaiChina
- Cancer Institute, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Department of Breast Surgery, Fudan University Shanghai Cancer CenterFudan UniversityShanghaiChina
- Shanghai Key Laboratory of Breast Cancer, Shanghai Medical CollegeFudan UniversityShanghaiChina
- Shanghai Key Laboratory of Radiation Oncology, Shanghai Medical CollegeFudan UniversityShanghaiChina
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Ranjan A, Thoenen EA, Kaida A, Wood S, Van Dyke T, Iwakuma T. Characterization of an Mtbp Hypomorphic Allele in a Diethylnitrosamine-Induced Liver Carcinogenesis Model. Cancers (Basel) 2023; 15:4596. [PMID: 37760565 PMCID: PMC10526184 DOI: 10.3390/cancers15184596] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2023] [Revised: 09/11/2023] [Accepted: 09/13/2023] [Indexed: 09/29/2023] Open
Abstract
MTBP is implicated in cell cycle progression, DNA replication, and cancer metastasis. However, the function of MTBP remains enigmatic and is dependent on cellular contexts and its cellular localization. To understand the in vivo physiological role of MTBP, it is important to generate Mtbp knockout mice. However, complete deletion of the Mtbp gene in mice results in early embryonic lethality, while its heterozygous deletion shows modest biological phenotypes, including enhanced cancer metastasis. To overcome this and better characterize the in vivo physiological function of MTBP, we, for the first time, generated mice that carry an Mtbp hypomorphic allele (MtbpH) in which Mtbp protein is expressed at approximately 30% of that in the wild-type allele. We treated wild-type, Mtbp+/-, and MtbpH/- mice with a liver carcinogen, diethylnitrosamine (DEN), and found that the MtbpH/- mice showed worse overall survival when compared to the wild-type mice. Consistent with previous reports using human liver cancer cells, mouse embryonic fibroblasts (MEFs) from the MtbpH/- mice showed an increase in the nuclear localization of p-Erk1/2 and migratory potential. Thus, MtbpH/- mice and cells from MtbpH/- mice are valuable to understand the in vivo physiological role of Mtbp and validate the diverse functions of MTBP that have been observed in human cells.
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Affiliation(s)
- Atul Ranjan
- Department of Pediatrics, Children’s Mercy Research Institute, Kansas City, MO 64108, USA
| | - Elizabeth A. Thoenen
- Department of Pediatrics, Children’s Mercy Research Institute, Kansas City, MO 64108, USA
| | - Atsushi Kaida
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Stephanie Wood
- Department of Pathology & Laboratory Medicine, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | | | - Tomoo Iwakuma
- Department of Pediatrics, Children’s Mercy Research Institute, Kansas City, MO 64108, USA
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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3
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Li M, Yang L, Chan AKN, Pokharel SP, Liu Q, Mattson N, Xu X, Chang W, Miyashita K, Singh P, Zhang L, Li M, Wu J, Wang J, Chen B, Chan LN, Lee J, Zhang XH, Rosen ST, Müschen M, Qi J, Chen J, Hiom K, Bishop AJR, Chen C. Epigenetic Control of Translation Checkpoint and Tumor Progression via RUVBL1-EEF1A1 Axis. ADVANCED SCIENCE (WEINHEIM, BADEN-WURTTEMBERG, GERMANY) 2023; 10:e2206584. [PMID: 37075745 PMCID: PMC10265057 DOI: 10.1002/advs.202206584] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 02/23/2023] [Indexed: 05/03/2023]
Abstract
Epigenetic dysregulation is reported in multiple cancers including Ewing sarcoma (EwS). However, the epigenetic networks underlying the maintenance of oncogenic signaling and therapeutic response remain unclear. Using a series of epigenetics- and complex-focused CRISPR screens, RUVBL1, the ATPase component of NuA4 histone acetyltransferase complex, is identified to be essential for EwS tumor progression. Suppression of RUVBL1 leads to attenuated tumor growth, loss of histone H4 acetylation, and ablated MYC signaling. Mechanistically, RUVBL1 controls MYC chromatin binding and modulates the MYC-driven EEF1A1 expression and thus protein synthesis. High-density CRISPR gene body scan pinpoints the critical MYC interacting residue in RUVBL1. Finally, this study reveals the synergism between RUVBL1 suppression and pharmacological inhibition of MYC in EwS xenografts and patient-derived samples. These results indicate that the dynamic interplay between chromatin remodelers, oncogenic transcription factors, and protein translation machinery can provide novel opportunities for combination cancer therapy.
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Affiliation(s)
- Mingli Li
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Lu Yang
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
- Division of Epigenetic and Transcriptional EngineeringBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Anthony K. N. Chan
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
- Division of Epigenetic and Transcriptional EngineeringBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Sheela Pangeni Pokharel
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
- Division of Epigenetic and Transcriptional EngineeringBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Qiao Liu
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Nicole Mattson
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Xiaobao Xu
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Wen‐Han Chang
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Kazuya Miyashita
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Priyanka Singh
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Leisi Zhang
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Maggie Li
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Jun Wu
- City of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Jinhui Wang
- City of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Bryan Chen
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Lai N. Chan
- Center of Molecular and Cellular OncologyYale Cancer CenterYale School of MedicineNew HavenCT06510USA
- Department of Cancer BiologyLerner Research InstituteCleveland ClinicClevelandOH44195USA
| | - Jaewoong Lee
- Center of Molecular and Cellular OncologyYale Cancer CenterYale School of MedicineNew HavenCT06510USA
- School of Biosystems and Biomedical SciencesCollege of Health ScienceKorea UniversitySeoul02841South Korea
- Interdisciplinary Program in Precision Public HealthKorea UniversitySeoul02841South Korea
| | | | | | - Markus Müschen
- Center of Molecular and Cellular OncologyYale Cancer CenterYale School of MedicineNew HavenCT06510USA
| | - Jun Qi
- Department of Cancer BiologyDana‐Farber Cancer InstituteHarvard Medical SchoolBostonMA02215USA
| | - Jianjun Chen
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
- City of Hope Comprehensive Cancer CenterDuarteCA91010USA
| | - Kevin Hiom
- Division of Cellular MedicineSchool of MedicineUniversity of DundeeNethergateDundeeDD1 4HNUK
| | - Alexander J. R. Bishop
- Department of Cellular Systems and AnatomyUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
- Greehey Children's Cancer Research InstituteUniversity of Texas Health Science Center at San AntonioSan AntonioTX78229USA
| | - Chun‐Wei Chen
- Department of Systems BiologyBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
- Division of Epigenetic and Transcriptional EngineeringBeckman Research InstituteCity of Hope Comprehensive Cancer CenterDuarteCA91010USA
- City of Hope Comprehensive Cancer CenterDuarteCA91010USA
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Adams CM, Mitra R, Xiao Y, Michener P, Palazzo J, Chao A, Gour J, Cassel J, Salvino JM, Eischen CM. Targeted MDM2 Degradation Reveals a New Vulnerability for p53-Inactivated Triple-Negative Breast Cancer. Cancer Discov 2023; 13:1210-1229. [PMID: 36734633 PMCID: PMC10164114 DOI: 10.1158/2159-8290.cd-22-1131] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 12/29/2022] [Accepted: 01/31/2023] [Indexed: 02/04/2023]
Abstract
Triple-negative breast cancers (TNBC) frequently inactivate p53, increasing their aggressiveness and therapy resistance. We identified an unexpected protein vulnerability in p53-inactivated TNBC and designed a new PROteolysis TArgeting Chimera (PROTAC) to target it. Our PROTAC selectively targets MDM2 for proteasome-mediated degradation with high-affinity binding and VHL recruitment. MDM2 loss in p53 mutant/deleted TNBC cells in two-dimensional/three-dimensional culture and TNBC patient explants, including relapsed tumors, causes apoptosis while sparing normal cells. Our MDM2-PROTAC is stable in vivo, and treatment of TNBC xenograft-bearing mice demonstrates tumor on-target efficacy with no toxicity to normal cells, significantly extending survival. Transcriptomic analyses revealed upregulation of p53 family target genes. Investigations showed activation and a required role for TAp73 to mediate MDM2-PROTAC-induced apoptosis. Our data, challenging the current MDM2/p53 paradigm, show MDM2 is required for p53-inactivated TNBC cell survival, and PROTAC-targeted MDM2 degradation is an innovative potential therapeutic strategy for TNBC and superior to existing MDM2 inhibitors. SIGNIFICANCE p53-inactivated TNBC is an aggressive, therapy-resistant, and lethal breast cancer subtype. We designed a new compound targeting an unexpected vulnerability we identified in TNBC. Our MDM2-targeted degrader kills p53-inactivated TNBC cells, highlighting the requirement for MDM2 in TNBC cell survival and as a new therapeutic target for this disease. See related commentary by Peuget and Selivanova, p. 1043. This article is highlighted in the In This Issue feature, p. 1027.
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Affiliation(s)
- Clare M. Adams
- Department of Pharmacology, Physiology and Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Ramkrishna Mitra
- Department of Pharmacology, Physiology and Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | | | - Peter Michener
- Department of Pharmacology, Physiology and Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
| | - Juan Palazzo
- Department of Pathology, Anatomy, and Cell Biology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Allen Chao
- The Wistar Institute, Philadelphia, PA, USA
| | | | | | | | - Christine M. Eischen
- Department of Pharmacology, Physiology and Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA, USA
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5
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Wang H, Chu F, Zhijie L, Bi Q, Lixin L, Zhuang Y, Xiaofeng Z, Niu X, Zhang D, Xi H, Li BA. MTBP enhances the activation of transcription factor ETS-1 and promotes the proliferation of hepatocellular carcinoma cells. Front Oncol 2022; 12:985082. [PMID: 36106099 PMCID: PMC9464980 DOI: 10.3389/fonc.2022.985082] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Accepted: 07/27/2022] [Indexed: 11/30/2022] Open
Abstract
Increasing evidence indicates that the oncoprotein murine double minute (MDM2) binding protein (MTBP) can be considered a pro-oncogene of human malignancies; however, its function and mechanisms in hepatocellular carcinoma (HCC) are still not clear. In the present work, our results demonstrate that MTBP could function as a co-activator of transcription factor E26 transformation-specific sequence (ETS-1), which plays an important role in HCC cell proliferation and/or metastasis and promotes proliferation of HCC cells. Using luciferase and real-time polymerase chain reaction (qPCR) assays, MTBP was found to enhance the transcription factor activation of ETS-1. The results from chromatin co-immunoprecipitation showed that MTBP enhanced the recruitment of ETS-1 to its downstream gene’s (mmp1’s) promoter region with ETS-1 binding sites. In cellular and nude mice models, overexpression of MTBP was shown to promote the proliferation of MHCC97-L cells with low endogenous MTBP levels, whereas the knockdown of MTBP led to inhibition of the proliferation of MHCC97-H cells that possessed high endogenous levels of MTBP. The effect of MTBP on ETS-1 was confirmed in the clinical specimens; the expression of MTBP was positively correlated with the downstream genes of ETS-1, mmp3, mmp9, and uPA. Therefore, by establishing the role of MTBP as a novel co-activator of ETS-1, this work expands our knowledge of MTBP or ETS-1 and helps to provide new ideas concerning HCC-related research.
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Affiliation(s)
- Hongbo Wang
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Fang Chu
- Department of Emergency, The Fifth Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Li Zhijie
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Qian Bi
- Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
| | - Li Lixin
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Yunlong Zhuang
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Zhang Xiaofeng
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Xiaofeng Niu
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Dali Zhang
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - He Xi
- Senior Department of Hepatology, The Fifth Medical Center of PLA General Hospital, Beijing, China
| | - Bo-an Li
- Clinical Laboratory, The Fifth Medical Center of Chinese People’s Liberation Army General Hospital, Beijing, China
- *Correspondence: Bo-an Li,
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Grieb BC, Eischen CM. MTBP and MYC: A Dynamic Duo in Proliferation, Cancer, and Aging. BIOLOGY 2022; 11:biology11060881. [PMID: 35741402 PMCID: PMC9219613 DOI: 10.3390/biology11060881] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/29/2022] [Accepted: 06/02/2022] [Indexed: 12/21/2022]
Abstract
The oncogenic transcription factor c-MYC (MYC) is highly conserved across species and is frequently overexpressed or dysregulated in human cancers. MYC regulates a wide range of critical cellular and oncogenic activities including proliferation, metabolism, metastasis, apoptosis, and differentiation by transcriptionally activating or repressing the expression of a large number of genes. This activity of MYC is not carried out in isolation, instead relying on its association with a myriad of protein cofactors. We determined that MDM Two Binding Protein (MTBP) indirectly binds MYC and is a novel MYC transcriptional cofactor. MTBP promotes MYC-mediated transcriptional activity, proliferation, and cellular transformation by binding in a protein complex with MYC at MYC-bound promoters. This discovery provided critical context for data linking MTBP to aging as well as a rapidly expanding body of evidence demonstrating MTBP is overexpressed in many human malignancies, is often linked to poor patient outcomes, and is necessary for cancer cell survival. As such, MTBP represents a novel and potentially broad reaching oncologic drug target, particularly when MYC is dysregulated. Here we have reviewed the discovery of MTBP and the initial controversy with its function as well as its associations with proliferation, MYC, DNA replication, aging, and human cancer.
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Affiliation(s)
- Brian C. Grieb
- Vanderbilt-Ingram Cancer Center, Division of Hematology/Oncology, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA;
- Department of Cell & Developmental Biology, Vanderbilt University School of Medicine, Nashville, TN 37232, USA
| | - Christine M. Eischen
- Department of Cancer Biology and the Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Correspondence:
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Zaffar E, Ferreira P, Sanchez-Pulido L, Boos D. The Role of MTBP as a Replication Origin Firing Factor. BIOLOGY 2022; 11:biology11060827. [PMID: 35741348 PMCID: PMC9219753 DOI: 10.3390/biology11060827] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 05/20/2022] [Accepted: 05/22/2022] [Indexed: 12/12/2022]
Abstract
The initiation step of replication at replication origins determines when and where in the genome replication machines, replisomes, are generated. Tight control of replication initiation helps facilitate the two main tasks of genome replication, to duplicate the genome accurately and exactly once each cell division cycle. The regulation of replication initiation must ensure that initiation occurs during the S phase specifically, that no origin fires more than once per cell cycle, that enough origins fire to avoid non-replicated gaps, and that the right origins fire at the right time but only in favorable circumstances. Despite its importance for genetic homeostasis only the main molecular processes of eukaryotic replication initiation and its cellular regulation are understood. The MTBP protein (Mdm2-binding protein) is so far the last core replication initiation factor identified in metazoan cells. MTBP is the orthologue of yeast Sld7. It is essential for origin firing, the maturation of pre-replicative complexes (pre-RCs) into replisomes, and is emerging as a regulation focus targeted by kinases and by regulated degradation. We present recent insight into the structure and cellular function of the MTBP protein in light of recent structural and biochemical studies revealing critical molecular details of the eukaryotic origin firing reaction. How the roles of MTBP in replication and other cellular processes are mutually connected and are related to MTBP's contribution to tumorigenesis remains largely unclear.
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Affiliation(s)
- Eman Zaffar
- Molecular Genetics II, Centre for Medical Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany; (E.Z.); (P.F.)
| | - Pedro Ferreira
- Molecular Genetics II, Centre for Medical Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany; (E.Z.); (P.F.)
| | - Luis Sanchez-Pulido
- Medical Research Council Human Genetics Unit, IGC, University of Edinburgh, Edinburgh EH9 3JR, UK;
| | - Dominik Boos
- Molecular Genetics II, Centre for Medical Biotechnology, University of Duisburg-Essen, 45141 Essen, Germany; (E.Z.); (P.F.)
- Correspondence: ; Tel.: +49-201-183-4132
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8
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Volpi I, Gillespie PJ, Chadha GS, Blow JJ. The role of DDK and Treslin-MTBP in coordinating replication licensing and pre-initiation complex formation. Open Biol 2021; 11:210121. [PMID: 34699733 PMCID: PMC8548084 DOI: 10.1098/rsob.210121] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2021] [Accepted: 09/21/2021] [Indexed: 01/04/2023] Open
Abstract
Treslin/Ticrr is required for the initiation of DNA replication and binds to MTBP (Mdm2 Binding Protein). Here, we show that in Xenopus egg extract, MTBP forms an elongated tetramer with Treslin containing two molecules of each protein. Immunodepletion and add-back experiments show that Treslin-MTBP is rate limiting for replication initiation. It is recruited onto chromatin before S phase starts and recruitment continues during S phase. We show that DDK activity both increases and strengthens the interaction of Treslin-MTBP with licensed chromatin. We also show that DDK activity cooperates with CDK activity to drive the interaction of Treslin-MTBP with TopBP1 which is a regulated crucial step in pre-initiation complex formation. These results suggest how DDK works together with CDKs to regulate Treslin-MTBP and plays a crucial in selecting which origins will undergo initiation.
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Affiliation(s)
- Ilaria Volpi
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Peter J. Gillespie
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - Gaganmeet Singh Chadha
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
| | - J. Julian Blow
- Centre for Gene Regulation and Expression, School of Life Sciences, University of Dundee, Dundee DD1 5EH, UK
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9
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Jiang Q, Ma Y, Han J, Chu J, Ma X, Shen L, Liu B, Li BA, Hou J, Bi Q. MDM2 Binding Protein Induces the Resistance of Hepatocellular Carcinoma Cells to Molecular Targeting Agents via Enhancing the Transcription Factor Activity of the Pregnane X Receptor. Front Oncol 2021; 11:715193. [PMID: 34249768 PMCID: PMC8264664 DOI: 10.3389/fonc.2021.715193] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2021] [Accepted: 06/07/2021] [Indexed: 12/16/2022] Open
Abstract
The MDM2 binding protein (MTBP) has been considered an important regulator of human malignancies. In this study, we demonstrate that the high level of MTBP’s endogenous expression is correlated with poor prognosis of advanced hepatocellular carcinoma (HCC) patients who received sorafenib. MTBP interacted with the Pregnane X receptor (PXR) and enhanced the transcription factor activity of PXR. Moreover, MTBP enhanced the accumulation of PXR in HCC cells’ nuclear and the recruitment of PXR to its downstream gene’s (cyp3a4’s) promoter region. Mechanically, the knockdown of MTBP in MHCC97-H cells with high levels of MTBP decelerated the clearance or metabolism of sorafenib in HCC cells and led to the resistance of HCC cells to sorafenib. Whereas overexpression of MTBP in in MHCC97-L cells with low levels of MTBP showed the opposite trend. By establishing the interaction between MTBP and PXR, our results indicate that MTBP could function as a co-activator of PXR and could be a promising therapeutic target to enhance the sensitivity of HCC cells to molecular targeting agents.
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Affiliation(s)
- Qiyu Jiang
- Institute of Infectious Disease, Department of Infectious Disease, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China.,Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Yan Ma
- Department of Gastroenterology and Hepatology, The First Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Jingjing Han
- Department of Gastroenterology, Sangzhi County National Hospital, Zhangjiajie City, China
| | - Jingdong Chu
- Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Xuemei Ma
- Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Lijun Shen
- Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Bo Liu
- Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Bo-An Li
- Department of Clinical Laboratory, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Jun Hou
- Institute of Infectious Disease, Department of Infectious Disease, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
| | - Qian Bi
- Endoscopy Center, Department of Hepatology, The Fifth Medical Center of Chinese PLA General Hospital, Beijing, China
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10
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Ben-Salem S, Venkadakrishnan VB, Heemers HV. Genomic alterations impact cell cycle-related genes during prostate cancer progression. Endocr Relat Cancer 2021; 28:L5-L10. [PMID: 33852421 PMCID: PMC8496939 DOI: 10.1530/erc-21-0091] [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] [Received: 04/09/2021] [Accepted: 04/14/2021] [Indexed: 11/08/2022]
Abstract
The recent genomic characterization of patient specimens has started to reveal the landscape of somatic alterations in clinical prostate cancer (CaP) and its association with disease progression and treatment resistance. The extent to which such alterations impact hallmarks of cancer is still unclear. Here, we interrogate genomic data from thousands of clinical CaP specimens that reflect progression from treatment-naïve, to castration-recurrent, and in some cases, neuroendocrine CaP for alterations in cell cycle-associated and -regulated genes, which are central to cancer initiation and progression. We evaluate gene signatures previously curated to evaluate G1-S and G2-M phase transitions or to represent the cell cycle-dependent proteome. The resulting CaP (stage)-specific overview confirmed the presence of well-known driver alterations impacting, for instance, the genes encoding p53 and MYC, and uncovered novel previously unrecognized mutations that affect others such as the PKMYT1 and MTBP genes. The cancer dependency and drugability of representative genomically altered cell cycle determinants were verified also. Taken together, these analyses on hundreds of often less-characterized cell cycle regulators expand considerably the scope of genomic alterations associated with CaP cell proliferation and cell cycle and isolate such regulatory proteins as putative drivers of CaP treatment resistance and entirely novel therapeutic targets for CaP therapy.
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Affiliation(s)
| | | | - Hannelore V Heemers
- Department of Cancer Biology, Lerner Research Institute, Cleveland Clinic, Cleveland, Ohio, USA
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11
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MTBP phosphorylation controls DNA replication origin firing. Sci Rep 2021; 11:4242. [PMID: 33608586 PMCID: PMC7895959 DOI: 10.1038/s41598-021-83287-w] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2020] [Accepted: 01/28/2021] [Indexed: 12/24/2022] Open
Abstract
Faithful genome duplication requires regulation of origin firing to determine loci, timing and efficiency of replisome generation. Established kinase targets for eukaryotic origin firing regulation are the Mcm2-7 helicase, Sld3/Treslin/TICRR and Sld2/RecQL4. We report that metazoan Sld7, MTBP (Mdm2 binding protein), is targeted by at least three kinase pathways. MTBP was phosphorylated at CDK consensus sites by cell cycle cyclin-dependent kinases (CDK) and Cdk8/19-cyclin C. Phospho-mimetic MTBP CDK site mutants, but not non-phosphorylatable mutants, promoted origin firing in human cells. MTBP was also phosphorylated at DNA damage checkpoint kinase consensus sites. Phospho-mimetic mutations at these sites inhibited MTBP’s origin firing capability. Whilst expressing a non-phospho MTBP mutant was insufficient to relieve the suppression of origin firing upon DNA damage, the mutant induced a genome-wide increase of origin firing in unperturbed cells. Our work establishes MTBP as a regulation platform of metazoan origin firing.
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Abstract
Despite the decline in death rate from breast cancer and recent advances in targeted therapies and combinations for the treatment of metastatic disease, metastatic breast cancer remains the second leading cause of cancer-associated death in U.S. women. The invasion-metastasis cascade involves a number of steps and multitudes of proteins and signaling molecules. The pathways include invasion, intravasation, circulation, extravasation, infiltration into a distant site to form a metastatic niche, and micrometastasis formation in a new environment. Each of these processes is regulated by changes in gene expression. Noncoding RNAs including microRNAs (miRNAs) are involved in breast cancer tumorigenesis, progression, and metastasis by post-transcriptional regulation of target gene expression. miRNAs can stimulate oncogenesis (oncomiRs), inhibit tumor growth (tumor suppressors or miRsupps), and regulate gene targets in metastasis (metastamiRs). The goal of this review is to summarize some of the key miRNAs that regulate genes and pathways involved in metastatic breast cancer with an emphasis on estrogen receptor α (ERα+) breast cancer. We reviewed the identity, regulation, human breast tumor expression, and reported prognostic significance of miRNAs that have been documented to directly target key genes in pathways, including epithelial-to-mesenchymal transition (EMT) contributing to the metastatic cascade. We critically evaluated the evidence for metastamiRs and their targets and miRNA regulation of metastasis suppressor genes in breast cancer progression and metastasis. It is clear that our understanding of miRNA regulation of targets in metastasis is incomplete.
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Affiliation(s)
- Belinda J Petri
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA
| | - Carolyn M Klinge
- Department of Biochemistry and Molecular Genetics, University of Louisville School of Medicine, Louisville, KY, 40292, USA.
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13
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Integrative genomics approach identifies molecular features associated with early-stage ovarian carcinoma histotypes. Sci Rep 2020; 10:7946. [PMID: 32409713 PMCID: PMC7224294 DOI: 10.1038/s41598-020-64794-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Accepted: 04/22/2020] [Indexed: 12/27/2022] Open
Abstract
Ovarian cancer comprises multiple subtypes (clear-cell (CCC), endometrioid (EC), high-grade serous (HGSC), low-grade serous (LGSC), and mucinous carcinomas (MC)) with differing molecular and clinical behavior. However, robust histotype-specific biomarkers for clinical use have yet to be identified. Here, we utilized a multi-omics approach to identify novel histotype-specific genetic markers associated with ovarian carcinoma histotypes (CCC, EC, HGSC, and MC) using DNA methylation, DNA copy number alteration and RNA sequencing data for 96 primary invasive early-stage (stage I and II) ovarian carcinomas. More specifically, the DNA methylation analysis revealed hypermethylation for CCC in comparison with the other histotypes. Moreover, copy number imbalances and novel chromothripsis-like rearrangements (n = 64) were identified in ovarian carcinoma, with the highest number of chromothripsis-like patterns in HGSC. For the 1000 most variable transcripts, underexpression was most prominent for all histotypes in comparison with normal ovarian samples. Overall, the integrative approach identified 46 putative oncogenes (overexpressed, hypomethylated and DNA gain) and three putative tumor suppressor genes (underexpressed, hypermethylated and DNA loss) when comparing the different histotypes. In conclusion, the current study provides novel insights into molecular features associated with early-stage ovarian carcinoma that may improve patient stratification and subclassification of the histotypes.
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14
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Song Y, Zhang L, Jiang Y, Hu T, Zhang D, Qiao Q, Wang R, Wang M, Han S. MTBP regulates cell survival and therapeutic sensitivity in TP53 wildtype glioblastomas. Am J Cancer Res 2019; 9:6019-6030. [PMID: 31534534 PMCID: PMC6735364 DOI: 10.7150/thno.35747] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2019] [Accepted: 07/25/2019] [Indexed: 01/21/2023] Open
Abstract
Background: Glioblastoma (GBM) is highly proliferative and resistant to radio-chemotherapy. Loss of tumor suppressor gene TP53 function frequently occurs at protein level in GBMs. This inhibition is often mediated by other components within the p53 signaling axis, including MDM2, whose binding protein (MTBP) plays an important role in the regulation of MDM2 and p53 activity. We investigated the role of MTBP in the biology of TP53-wildtype (TP53wt) GBMs. Methods: MTBP expression was examined in TCGA and REMBRANDT datasets. MTBP was silenced or overexpressed in TP53wt GBM cells and glioma stem cells (GSCs). The effects on cell viability, apoptosis, and clonogenicity were assessed. The transcriptional regulation of MTBP was investigated. Results: Upregulation of MTBP was correlated with the Classical molecular subtype, and it predicted poor survival. In TP53wt GBM cells, the protein levels of MTBP were positively associated with those of MDM2 but negatively correlated with those of p53. MTBP knockdown promoted apoptosis and inhibited clonogenicity, while overexpression of this protein enhanced tumorigenicity in vitro and in vivo. The pro-survival effect of MTBP depended on the activity of MDM2 and p53. MTBP was transcriptionally regulated by c-myc, thereby forming a positive regulatory loop. Finally, MTBP silencing increased the sensitivity of TP53wt GSCs to radiation and TMZ treatment in vitro and in vivo. Conclusion: MTBP regulates the cell survival and treatment sensitivity of TP53wt GBMs through MDM2-dependent post-translational modification of p53. MTBP-targeting treatments are potentially useful in increasing patients' survival.
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15
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Hwang SY, Park S, Kwon Y. Recent therapeutic trends and promising targets in triple negative breast cancer. Pharmacol Ther 2019; 199:30-57. [PMID: 30825473 DOI: 10.1016/j.pharmthera.2019.02.006] [Citation(s) in RCA: 132] [Impact Index Per Article: 26.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 02/04/2019] [Indexed: 12/14/2022]
Abstract
Breast cancer accounts for 25% of all types of cancer in women, and triple negative breast cancer (TNBC) comprises around 15~20% of breast cancers. Conventional chemotherapy and radiation are the primary systemic therapeutic strategies; no other FDA-approved targeted therapies are yet available as for TNBC. TNBC is generally characterized by a poor prognosis and high rates of proliferation and metastases. Due to these aggressive features and lack of targeted therapies, numerous attempts have been made to discover viable molecular targets for TNBC. Massive cohort studies, clinical trials, and in-depth analyses have revealed diverse molecular alterations in TNBC; however, controversy exists as to whether many of these changes are beneficial or detrimental in caner progression. Here we review the complicated tumorigenic processes and discuss critical findings and therapeutic trends in TNBC with a focus on promising therapeutic approaches, the clinical trials currently underway, and potent experimental compounds under preclinical and evaluation.
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Affiliation(s)
- Soo-Yeon Hwang
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Seojeong Park
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea
| | - Youngjoo Kwon
- College of Pharmacy, Graduate School of Pharmaceutical Sciences, Ewha Womans University, Seoul 03760, Republic of Korea.
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16
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Xiao Z, Chen M, Yang J, Yang C, Lü X, Tian H, Liu C. [MTBP regulates migration and invasion of prostate cancer cells in vitro]. NAN FANG YI KE DA XUE XUE BAO = JOURNAL OF SOUTHERN MEDICAL UNIVERSITY 2019; 39:6-12. [PMID: 30692060 DOI: 10.12122/j.issn.1673-4254.2019.01.02] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
OBJECTIVE To investigate the role of MTBP in regulating the migration and invasion of human prostate cancer cells. METHODS The baseline expressions of MTBP in 3 different human prostate cancer cells lines (22RV1, DU145 and Lncap) were detected using Western blotting. The cells were transfected with a small interfering RNA (siRNA) for MTBP knockdown or MTBP plasmid for MTBP overexpression, and 48 h later, the cells were examined for MTBP expression with Western blotting; the changes in the migration abilities of the cells were evaluated using wound healing assay and Transwell assay, and the cell invasiveness was assessed using Matrigel Transwell assay. The expression of E-cadherin protein, a marker of epithelial mesenchymal transition (EMT), was detected using Western blotting. RESULTS MTBP expression was the highest in DU145 cells followed by Lncap cells, and was the lowest in 22RV1 cells, indicating a positive correlation of MTBP expression with the level of malignancy of human prostate cancer cells. Transfection of the cells with siRNA or MTBP plasmids efficiently lowered or enhanced the expressions of MTBP in human prostate cancer cells. Wound healing assay showed that inhibition of MTBP expression decreased the migration ability of the prostate cancer cells, and MTBP overexpression significantly promoted the migration of the cells (P < 0.01). Transwell assay showed that MTBP knockdown significantly lowered the migration and invasion ability of the cells, while MTBP overexpression markedly increased the number of migrating and invading cells (P < 0.01); Western blotting results showed that MTBP knockdown increased the expression of E-cadherin protein, and MTBP overexpression decreased E-cadherin expression in the prostate cancer cells. CONCLUSIONS MTBP overexpression promotes the migration and invasion of human prostate cancer cells possibly relation to the induction of EMT.
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Affiliation(s)
- Zhuoyu Xiao
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Mingkun Chen
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Jiankun Yang
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Cheng Yang
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Xianyuan Lü
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Hu Tian
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
| | - Cundong Liu
- Department of Urology, Third Affiliated Hospital of Southern Medical University, Guangzhou 510630, China
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17
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Puccetti MV, Adams CM, Kushinsky S, Eischen CM. Smarcal1 and Zranb3 Protect Replication Forks from Myc-Induced DNA Replication Stress. Cancer Res 2019; 79:1612-1623. [PMID: 30610086 DOI: 10.1158/0008-5472.can-18-2705] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Revised: 11/08/2018] [Accepted: 12/27/2018] [Indexed: 02/01/2023]
Abstract
The cellular DNA replication stress response functions to stabilize DNA replication forks and inhibits genome instability and tumorigenesis induced by oncogenes. However, the specific proteins required for resolving oncogenic stress remain poorly understood. Here we report that Smarcal1 and Zranb3, closely related replication fork-remodeling proteins, have nonredundant functions in resolving Myc-induced DNA replication stress. In Myc-overexpressing primary cells, significant differences in replication fork stalling, collapse, and DNA damage were detected between cells deficient in Smarcal1 or Zranb3, leading to changes in proliferation and apoptosis. These differences were also reflected in Myc-induced lymphoma development; haploinsufficiency of Smarcal1 resulted in accelerated lymphomagenesis, whereas haploinsufficiency of Zranb3 inhibited lymphoma development. Complete loss of either protein resulted in disparate survival outcomes. Our results reveal that endogenous replication stress from Myc in primary cells requires both alleles of Smarcal1 and Zranb3 and demonstrate the requirement of both proteins to stabilize replication forks upon Myc dysregulation in a nonredundant manner. SIGNIFICANCE: Smarcal1 and Zranb3 are essential, but nonredundant, for responding to DNA replication stress and stabilizing replication forks following Myc overexpression.See related commentary by Sotiriou and Halazonetis, p. 1297.
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Affiliation(s)
- Matthew V Puccetti
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.,Medical Scientist Training Program, Vanderbilt University School of Medicine, Nashville, Tennessee
| | - Clare M Adams
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Saul Kushinsky
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christine M Eischen
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, Pennsylvania.
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18
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Pan B, Han H, Wu L, Xiong Y, Zhang J, Dong B, Yang Y, Chen J. MTBP promotes migration and invasion by regulation of ZEB2-mediated epithelial-mesenchymal transition in lung cancer cells. Onco Targets Ther 2018; 11:6741-6756. [PMID: 30349307 PMCID: PMC6188014 DOI: 10.2147/ott.s167963] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Background It is clearly necessary to discover prognostic biomarkers to identify stage I patients at risk of recurrence and give them timely postoperative treatment. Materials and methods Data of stage I lung adenocarcinoma were retrieved from four gene series in Gene Expression Omnibus (GEO) database (GSE50081, GSE30219, GSE37745, and GSE13213). Partek Genomics Suite software was used to identify survival-related genes for finding candidate indicators for early-stage patients at risk of recurrence. Differential expression of MTBP (MDM2 binding protein) in early-stage lung adenocarcinoma tissues was determined by immunohistochemical staining. The effects of MTBP interference expression and overexpression on viability, migration, and invasion capacity of lung cells were evaluated using Cell Counting Kit-8, wound healing, and Transwell assays. The tumor growth and lung metastasis in vivo were observed in chick embryo chorioallantoic membrane model. Human Exon 2.0 ST Array was used to analyze downstream regulation genes of MTBP in lung cancer cells. Involvement of ZEB2 and epithelial–mesenchymal transition (EMT) markers was investigated by Western blot. Results By mining GEO database, we identified MTBP as a poor prognostic indicator of stage I lung adenocarcinomas. In addition, increased expression of MTBP was also associated with poor survival in our early-stage lung adenocarcinoma cohort. Further experiment suggested that knockdown of MTBP suppressed the migration and invasion of A549 and H1975 cells in vitro and in vivo, whereas overexpression of MTBP in HCC827 and PC9 cells promoted the migration and invasion in vitro and in vivo. Furthermore, ZEB2 upregulation directly activated EMT to mediate the downstream effects of MTBP involved in lung cancer cells metastasis. Conclusion MTBP is an independent indicator for poor prognosis in stage I lung adenocarcinomas and might promote the aggressive phenotype of non-small-cell lung cancer by inducing the EMT process through upregulating ZEB2 expression.
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Affiliation(s)
- Bo Pan
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China, ,
| | - Haibo Han
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Biobank, Peking University Cancer Hospital & Institute, Beijing, China
| | - Lina Wu
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Central Laboratory, Peking University Cancer Hospital & Institute, Beijing, China
| | - Ying Xiong
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China, ,
| | - Jianzhi Zhang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China, ,
| | - Bin Dong
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Central Laboratory, Peking University Cancer Hospital & Institute, Beijing, China
| | - Yue Yang
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China, ,
| | - Jinfeng Chen
- Key Laboratory of Carcinogenesis and Translational Research (Ministry of Education/Beijing), Beijing, China, , .,Department of Thoracic Surgery II, Peking University Cancer Hospital & Institute, Beijing, China, ,
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19
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Greenawalt EJ, Edmonds MD, Jain N, Adams CM, Mitra R, Eischen CM. Targeting of SGK1 by miR-576-3p Inhibits Lung Adenocarcinoma Migration and Invasion. Mol Cancer Res 2018; 17:289-298. [PMID: 30257988 DOI: 10.1158/1541-7786.mcr-18-0364] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2018] [Revised: 06/28/2018] [Accepted: 09/06/2018] [Indexed: 01/07/2023]
Abstract
Metastatic lung cancer is common in patients with lung adenocarcinoma, but the molecular mechanisms of metastasis remain incompletely resolved. miRNA regulate gene expression and contribute to cancer development and progression. This report identifies miR-576-3p and its mechanism of action in lung cancer progression. miR-576-3p was determined to be significantly decreased in clinical specimens of late-stage lung adenocarcinoma. Overexpression of miR-576-3p in lung adenocarcinoma cells decreased mesenchymal marker expression and inhibited migration and invasion. Inhibition of miR-576-3p in nonmalignant lung epithelial cells increased migration and invasion as well as mesenchymal markers. Serum/glucocorticoid-regulated kinase 1 (SGK1) was a direct target of miR-576-3p, and modulation of miR-576-3p levels led to alterations in SGK1 protein and mRNA as well as changes in activation of its downstream target linked to metastasis, N-myc downstream regulated 1 (NDRG1). Loss of the ability of miR-576-3p to bind the 3'-UTR of SGK1 rescued the inhibition in migration and invasion observed with miR-576-3p overexpression. In addition, increased SGK1 levels were detected in lung adenocarcinoma patient samples expressing mesenchymal markers, and pharmacologic inhibition of SGK1 resulted in a similar inhibition of migration and invasion of lung adenocarcinoma cells as observed with miR-576-3p overexpression. Together, these results reveal miR-576-3p downregulation is selected for in late-stage lung adenocarcinoma due to its ability to inhibit migration and invasion by targeting SGK1. Furthermore, these results also support targeting SGK1 as a potential therapeutic for lung adenocarcinoma. IMPLICATIONS: This study reveals SGK1 inhibition with miR-576-3p or pharmacologically inhibits migration and invasion of lung adenocarcinoma, providing mechanistic insights into late-stage lung adenocarcinoma and a potential new treatment avenue.
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Affiliation(s)
- Evan J Greenawalt
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Mick D Edmonds
- Department of Genetics, University of Alabama, Birmingham, Alabama
| | - Neha Jain
- Vanderbilt Ingram Cancer Center, Nashville, Tennessee
| | - Clare M Adams
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Ramkrishna Mitra
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania
| | - Christine M Eischen
- Department of Cancer Biology, Thomas Jefferson University, Philadelphia, Pennsylvania.
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20
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Mao Y, Tian M, Pan B, Zhu Q, Li P, Liu H, Liu W, Dai N, Yu L, Tian Y. Hyper expression of MTBP may be an adverse signal for the survival of some malignant tumors: A data-based analysis and clinical observation. Medicine (Baltimore) 2018; 97:e12021. [PMID: 30170409 PMCID: PMC6392579 DOI: 10.1097/md.0000000000012021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
To explore the relationship between mouse double minute 2 binding protein (MTBP) and the prognosis of cancer patients, a databank-based reanalysis was conducted and a clinical observation about lung adenocarcinoma was taken to verify the result of data analysis.We reanalyzed all the downloaded data in order to make a conclusion about the relationship between MTBP and the prognosis of cancer patients. At last, we collected 112 lung cancer patients with MTBP information to verify the results of data analysis (GSE30219).The overall Kaplan-Meier curve results of 6 eligible data groups were shown in Fig. 1. The Kaplan-Meier curve result of GSE16011 was shown in Fig. 1A (concordance index = 59.48, Log-Rank Equal Curves [P = 5.942e-05], R = 0.045/1, risk groups hazard ratio = 1.69 [conf. int. 1.3-2.9], P = 7.344e-05), while the stratification results were displayed independently in Figs. 2 and 3. The similar results could be seen in other 5 data groups. The tissue sections of 112 patients with lung adenocarcinoma were collected and immunohistochemically stained. The hyper expression rate of MTBP in adenocarcinoma was 23.21% (26/112). The results showed that patients with hyper expression of MTBP had significantly worse prognosis than the control group, and the survival curves were clearly separated from each other (Fig. 4B, P = .000).Hyper expression of MTBP maybe an adverse event for the survival of some cancer patients, especially in glioblastoma, kidney cancer, and lung cancer patients, which has been verified in 112 lung cancer patients with MTBP status.
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Affiliation(s)
- Yantao Mao
- Department of Oncology, Yantaishan Hospital of Shandong Province, Zhifu District, Yantai City
| | - Mei Tian
- Respiratory Department, Affiliated Hospital of Shandong University of Traditional Chinese Medicine, Jinan, Shandong
| | - Bo Pan
- Department of Lung Transplantation, First Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou
| | - Qingshan Zhu
- Department of Radiotherapy Oncology, Anyang Cancer Hospital of Henan Province, Anyang, Henan
| | - Paiyun Li
- Division of Etiology, Peking University Cancer Hospital and Institute, Beijing
| | - Hongmei Liu
- Department of Radiation Oncology, Shandong Provincial Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Weipeng Liu
- Department of Radiotherapy Oncology, Anyang Cancer Hospital of Henan Province, Anyang, Henan
| | - Ningtao Dai
- Department of Radiotherapy Oncology, Anyang Cancer Hospital of Henan Province, Anyang, Henan
| | - Lili Yu
- Department of Radiation Oncology, Shandong Provincial Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong, China
| | - Yuan Tian
- Department of Radiation Oncology, Shandong Provincial Qianfoshan Hospital Affiliated to Shandong University, Jinan, Shandong, China
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21
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MTBP inhibits the Erk1/2-Elk-1 signaling in hepatocellular carcinoma. Oncotarget 2018; 9:21429-21443. [PMID: 29765550 PMCID: PMC5940416 DOI: 10.18632/oncotarget.25117] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 03/21/2018] [Indexed: 01/14/2023] Open
Abstract
Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide, and the prognosis of HCC patients, especially those with metastasis, remains extremely poor. This is partly due to unclear molecular mechanisms underlying HCC metastasis. Our previous study indicates that MDM2 Binding Protein (MTBP) suppresses migration and metastasis of HCC cells. However, signaling pathways regulated by MTBP remain unknown. To identify metastasis-associated signaling pathways governed by MTBP, we have performed unbiased luciferase reporter-based signal array analyses and found that MTBP suppresses the activity of the ETS-domain transcription factor Elk-1, a downstream target of Erk1/2 MAP kinases. MTBP also inhibits phosphorylation of Elk-1 and decreases mRNA expression of Elk-1 target genes. Reduced Elk-1 activity is caused by inhibited nuclear translocation of phosphorylated Erk1/2 (p-Erk) by MTBP and subsequent inhibition of Elk-1 phosphorylation. We also reveal that MTBP inhibits the interaction of p-Erk with importin-7/RanBP7 (IPO7), an importin family member which shuttles p-Erk into the nucleus, by binding to IPO7. Moreover, high levels of MTBP in human HCC tissues are correlated with cytoplasmic localization of p-Erk1/2. Our study suggests that MTBP suppresses metastasis, at least partially, by down-modulating the Erk1/2-Elk-1 signaling pathway, thus identifying a novel regulatory mechanism of HCC metastasis by regulating the subcellular localization of p-Erk.
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22
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Mao YQ, Houry WA. The Role of Pontin and Reptin in Cellular Physiology and Cancer Etiology. Front Mol Biosci 2017; 4:58. [PMID: 28884116 PMCID: PMC5573869 DOI: 10.3389/fmolb.2017.00058] [Citation(s) in RCA: 80] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2017] [Accepted: 08/03/2017] [Indexed: 12/29/2022] Open
Abstract
Pontin (RUVBL1, TIP49, TIP49a, Rvb1) and Reptin (RUVBL2, TIP48, TIP49b, Rvb2) are highly conserved ATPases of the AAA+ (ATPases Associated with various cellular Activities) superfamily and are involved in various cellular processes that are important for oncogenesis. First identified as being upregulated in hepatocellular carcinoma and colorectal cancer, their overexpression has since been shown in multiple cancer types such as breast, lung, gastric, esophageal, pancreatic, kidney, bladder as well as lymphatic, and leukemic cancers. However, their exact functions are still quite unknown as they interact with many molecular complexes with vastly different downstream effectors. Within the nucleus, Pontin and Reptin participate in the TIP60 and INO80 complexes important for chromatin remodeling. Although not transcription factors themselves, Pontin and Reptin modulate the transcriptional activities of bona fide proto-oncogenes such as MYC and β-catenin. They associate with proteins involved in DNA damage repair such as PIKK complexes as well as with the core complex of Fanconi anemia pathway. They have also been shown to be important for cell cycle progression, being involved in assembly of telomerase, mitotic spindle, RNA polymerase II, and snoRNPs. When the two ATPases localize to the cytoplasm, they were reported to promote cancer cell invasion and metastasis. Due to their various roles in carcinogenesis, it is not surprising that Pontin and Reptin are proving to be important biomarkers for diagnosis and prognosis of various cancers. They are also current targets for the development of new therapeutic anticancer drugs.
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Affiliation(s)
- Yu-Qian Mao
- Department of Biochemistry, University of TorontoToronto, ON, Canada
| | - Walid A Houry
- Department of Biochemistry, University of TorontoToronto, ON, Canada.,Department of Chemistry, University of TorontoToronto, ON, Canada
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Adult high-grade B-cell lymphoma with Burkitt lymphoma signature: genomic features and potential therapeutic targets. Blood 2017; 130:1819-1831. [PMID: 28801451 DOI: 10.1182/blood-2017-02-767335] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2017] [Accepted: 07/22/2017] [Indexed: 12/15/2022] Open
Abstract
The adult high-grade B-cell lymphomas sharing molecular features with Burkitt lymphoma (BL) are highly aggressive lymphomas with poor clinical outcome. High-resolution structural and functional genomic analysis of adult Burkitt lymphoma (BL) and high-grade B-cell lymphoma with BL gene signature (adult-molecularly defined BL [mBL]) revealed the MYC-ARF-p53 axis as the primary deregulated pathway. Adult-mBL had either unique or more frequent genomic aberrations (del13q14, del17p, gain8q24, and gain18q21) compared with pediatric-mBL, but shared commonly mutated genes. Mutations in genes promoting the tonic B-cell receptor (BCR)→PI3K pathway (TCF3 and ID3) did not differ by age, whereas effectors of chronic BCR→NF-κB signaling were associated with adult-mBL. A subset of adult-mBL had BCL2 translocation and mutation and elevated BCL2 mRNA and protein expression, but had a mutation profile similar to mBL. These double-hit lymphomas may have arisen from a tumor precursor that acquired both BCL2 and MYC translocations and/or KMT2D (MLL2) mutation. Gain/amplification of MIR17HG and its paralogue loci was observed in 50% of adult-mBL. In vitro studies suggested miR-17∼92's role in constitutive activation of BCR signaling and sensitivity to ibrutinib. Overall integrative analysis identified an interrelated gene network affected by copy number and mutation, leading to disruption of the p53 pathway and the BCR→PI3K or NF-κB activation, which can be further exploited in vivo by small-molecule inhibitors for effective therapy in adult-mBL.
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Feeley KP, Adams CM, Mitra R, Eischen CM. Mdm2 Is Required for Survival and Growth of p53-Deficient Cancer Cells. Cancer Res 2017; 77:3823-3833. [PMID: 28576884 DOI: 10.1158/0008-5472.can-17-0809] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Revised: 05/15/2017] [Accepted: 05/24/2017] [Indexed: 02/06/2023]
Abstract
p53 deletion prevents the embryonic lethality of normal tissues lacking Mdm2, suggesting that cells can survive without Mdm2 if p53 is also absent. Here we report evidence challenging this view, with implications for therapeutically targeting Mdm2. Deletion of Mdm2 in T-cell lymphomas or sarcomas lacking p53 induced apoptosis and G2 cell-cycle arrest, prolonging survival of mice with these tumors. p53-/- fibroblasts showed similar results, indicating that the effects of Mdm2 loss extend to premalignant cells. Mdm2 deletion in p53-/- cells upregulated p53 transcriptional target genes that induce apoptosis and cell-cycle arrest. Mdm2 deletion also increased levels of p73, a p53 family member. RNAi-mediated attenuation of p73 rescued the transcriptional and biological effects of Mdm2 loss, indicating that p73 mediates the consequences of Mdm2 deletion. In addition, Mdm2 deletion differed from blocking Mdm2 interaction with p53 family members, as Nutlin-3 induced G1 arrest but did not activate apoptosis in p53-/- sarcoma cells. Our results indicate that, in contrast to current dogma, Mdm2 expression is required for cell survival even in the absence of p53. Moreover, our results suggest that p73 compensates for loss of p53 and that targeting Mdm2 in p53-deficient cancers has therapeutic potential. Cancer Res; 77(14); 3823-33. ©2017 AACR.
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Affiliation(s)
- Kyle P Feeley
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Clare M Adams
- Department of Cancer Biology, Thomas Jefferson University, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
| | - Ramkrishna Mitra
- Department of Cancer Biology, Thomas Jefferson University, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee. .,Department of Cancer Biology, Thomas Jefferson University, Sidney Kimmel Cancer Center, Philadelphia, Pennsylvania
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Grieb BC, Boyd K, Mitra R, Eischen CM. Haploinsufficiency of the Myc regulator Mtbp extends survival and delays tumor development in aging mice. Aging (Albany NY) 2016; 8:2590-2602. [PMID: 27803394 PMCID: PMC5115908 DOI: 10.18632/aging.101092] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Accepted: 10/15/2016] [Indexed: 04/20/2023]
Abstract
Alterations of specific genes can modulate aging. Myc, a transcription factor that regulates the expression of many genes involved in critical cellular functions was shown to have a role in controlling longevity. Decreased expression of Myc inhibited many of the deleterious effects of aging and increased lifespan in mice. Without altering Myc expression, reduced levels of Mtbp, a recently identified regulator of Myc, limit Myc transcriptional activity and proliferation, while increased levels promote Myc-mediated effects. To determine the contribution of Mtbp to the effects of Myc on aging, we studied a large cohort of Mtbp heterozygous mice and littermate matched wild-type controls. Mtbp haploinsufficiency significantly increased longevity and maximal survival in mice. Reduced levels of Mtbp did not alter locomotor activity, litter size, or body size, but Mtbp heterozygous mice did exhibit elevated markers of metabolism, particularly in the liver. Mtbp+/- mice also had a significant delay in spontaneous cancer development, which was most prominent in the hematopoietic system, and an altered tumor spectrum compared to Mtbp+/+ mice. Therefore, the data suggest Mtbp is a regulator of longevity in mice that mimics some, but not all, of the properties of Myc in aging.
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Affiliation(s)
- Brian C. Grieb
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Kelli Boyd
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
| | - Ramkrishna Mitra
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Christine M. Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, TN 37212, USA
- Department of Cancer Biology, Sidney Kimmel Cancer Center, Thomas Jefferson University, Philadelphia, PA 19107, USA
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Yuan XS, Wang ZT, Hu YJ, Bao FC, Yuan P, Zhang C, Cao JL, Lv W, Hu J. Downregulation of RUVBL1 inhibits proliferation of lung adenocarcinoma cells by G1/S phase cell cycle arrest via multiple mechanisms. Tumour Biol 2016; 37:10.1007/s13277-016-5452-9. [PMID: 27722820 DOI: 10.1007/s13277-016-5452-9] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/23/2016] [Indexed: 02/08/2023] Open
Abstract
Lung cancer remains a leading cause of cancer-related mortality and morbidity worldwide, of which non-small cell lung cancer (NSCLC) accounts for 80 %. RUVBL1 is a highly conserved eukaryotic AAA+ adenosine 5'-triphosphatase (ATPase) that has many functions highly relevant to cancer. We therefore attempted to determine the potential role of RUVBL1 in the biogenesis of lung adenocarcinoma and obtained some interesting results. Our study revealed that RUVBL1 expression was higher in lung adenocarcinoma specimens than in those of adjacent non-tumor tissues and in lung cancer cell lines than in normal lung cell lines. RUVBL1 knockdown via siRNA reduced proliferation and caused G1/S phase cell cycle arrest in lung adenocarcinoma cell lines. The G1/S phase cell cycle arrest triggered by RUVBL1 downregulation could be attributed, at least in part, to repression of the AKT/GSK-3β/cyclin D1 pathway and probably to the activation of IRE1α-mediated endoplasmic reticulum (ER) stress. We thus demonstrated for the first time that a knockdown of RUVBL1 could effectively inhibit the proliferation of lung adenocarcinoma A549 and H292 cells through the induction of G1/S phase cell cycle arrest via multiple mechanisms. These observations strongly suggested that RUVBL1 should be considered a promising target for the prevention or therapy of lung adenocarcinoma.
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Affiliation(s)
- Xiao-Shuai Yuan
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Zhi-Tian Wang
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Ye-Ji Hu
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Fei-Chao Bao
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Ping Yuan
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Chong Zhang
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Jin-Lin Cao
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Wang Lv
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China
| | - Jian Hu
- Department of Thoracic Surgery, First Affiliated Hospital of Zhejiang University, No.79, Qingchun Road, Hangzhou, China.
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Yan FQ, Wang JQ, Tsai YP, Wu KJ. HSP60 overexpression increases the protein levels of the p110α subunit of phosphoinositide 3-kinase and c-Myc. Clin Exp Pharmacol Physiol 2016; 42:1092-7. [PMID: 26174078 DOI: 10.1111/1440-1681.12457] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 07/07/2015] [Accepted: 07/09/2015] [Indexed: 12/26/2022]
Abstract
Heat shock protein 60 (HSP60) is a chaperone protein which plays an essential role in facilitating the folding of many newly synthesized proteins to reach their native forms. Increased HSP60 expression is observed in various types of human cancers. However, proteins induced by HSP60 to mediate transformation remain largely unknown. Here we show that HSP60 overexpression increases the protein levels of the p110α subunit of phosphoinositide 3-kinase (PI3K). The amino acid domain 288-383 of HSP60 is used to increase the protein levels. Overexpression of HSP60 also induces the levels of phosphorylated Akt. In addition, the amino acid domain 288-383 of HSP60 is used to induce c-Myc expression. Finally, a mono-ubiquitinated form of β-catenin has a higher activity to activate β-catenin downstream targets compared to wild-type β-catenin. These results indicate that HSP60 overexpression induces the levels or activity of multiple oncogenic proteins to mediate transformation.
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Affiliation(s)
- Feng-Qin Yan
- Department of Radiotherapy, Zhejiang Cancer Hospital, Hangzhou, China
| | - Jian-Qiu Wang
- Institute of Ageing Research, School of Medicine, Hangzhou Normal University, Hangzhou, China
| | - Ya-Ping Tsai
- Genome Research Centre, National Yang-Ming University, Taipei, Taiwan
| | - Kou-Juey Wu
- Research Centre for Tumor Medical Science, Graduate Institute of Cancer Biology, China Medical University, Taichung, Taiwan
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Ranjan A, Bera K, Iwakuma T. Murine double minute 2, a potential p53-independent regulator of liver cancer metastasis. ACTA ACUST UNITED AC 2016; 2:114-121. [PMID: 28944296 PMCID: PMC5609474 DOI: 10.20517/2394-5079.2015.67] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Hepatocellular carcinoma (HCC) has emerged as one of the most commonly diagnosed forms of human cancer; yet, the mechanisms underlying HCC progression remain unclear. Unlike other cancers, systematic chemotherapy is not effective for HCC patients, while surgical resection and liver transplantation are the most viable treatment options. Thus, identifying factors or pathways that suppress HCC progression would be crucial for advancing treatment strategies for HCC. The murine double minute 2 (MDM2)-p53 pathway is impaired in most of the cancer types, including HCC, and MDM2 is overexpressed in approximately 30% of HCC. Overexpression of MDM2 is reported to be well correlated with metastasis, drug resistance, and poor prognosis of multiple cancer types, including HCC. Importantly, these correlations are observed even when p53 is mutated. Indeed, p53-independent functions of overexpressed MDM2 in cancer progression have been suitably demonstrated. In this review article, we summarize potential effectors of MDM2 that promote or suppress cancer metastasis and discuss the p53-independent roles of MDM2 in liver cancer metastasis from clinical as well as biological perspectives.
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Affiliation(s)
- Atul Ranjan
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Kaustav Bera
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Tomoo Iwakuma
- Department of Cancer Biology, University of Kansas Medical Center, Kansas City, KS 66160, USA
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29
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Li P, Shi JX, Dai LP, Chai YR, Zhang HF, Kankonde M, Kankonde P, Yu BF, Zhang JY. Serum anti-MDM2 and anti-c-Myc autoantibodies as biomarkers in the early detection of lung cancer. Oncoimmunology 2016; 5:e1138200. [PMID: 27467958 DOI: 10.1080/2162402x.2016.1138200] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Revised: 12/17/2015] [Accepted: 12/29/2015] [Indexed: 12/12/2022] Open
Abstract
This study aims to investigate the clinical significance of serum autoantibodies against MDM2 and c-Myc and evaluate their feasibility in the immunodiagnosis of lung cancer. 50 sera samples with 43 available paired lung cancer tissue and adjacent normal tissue slides with follow up information and 44 sera from normal human controls (NHC) were used in the research group. Another 62 lung cancer sera and 43 NHC sera were used in the validation group. The results of IHC showed that MDM2 and c-Myc protein were overexpressed in lung cancer tissues compared to adjacent normal tissues (p < 0.001). Likewise, significantly higher levels of serum autoantibodies against MDM2 and c-Myc were found in lung cancer compared to NHC both in research and validation groups. Further analysis on IHC and ELISA results showed that serum level of autoantibodies against these two TAAs were positively associated with tissue staining scores (both p < 0.05). The area under curve (AUC) values of anti-MDM2 and anti-cMyc autoantibodies for discriminating lung cancers from NHC were 0.698 and 0.636 in research group, 0.777 and 0.815 in the validation group, respectively. Both anti-MDM2 and anti-c-Myc autoantibodies can discriminate stage I lung cancer patients from NHC with AUC values of 0.703 and 0.662. Kaplan-Meier analysis showed that higher level of serum anti-c-Myc autoantibodies was significantly related to shortened disease-free survival (DFS) (p = 0.041). In conclusion, our finding suggested that serum MDM2 and c-Myc autoantibodies may have the potential to serve as non-invasive diagnostic biomarkers in patients with lung cancer.
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Affiliation(s)
- Pei Li
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China; Department of Biological Sciences, The University of Texas at El Paso, 500 W University Ave, El Paso, TX, USA
| | - Jian-Xiang Shi
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China; Department of Biological Sciences, The University of Texas at El Paso, 500 W University Ave, El Paso, TX, USA; Henan Key Laboratory for Tumor Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Li-Ping Dai
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China; Department of Biological Sciences, The University of Texas at El Paso, 500 W University Ave, El Paso, TX, USA; Henan Key Laboratory for Tumor Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Yu-Rong Chai
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China; Department of Biological Sciences, The University of Texas at El Paso, 500 W University Ave, El Paso, TX, USA
| | - Hong-Fei Zhang
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China; Department of Biological Sciences, The University of Texas at El Paso, 500 W University Ave, El Paso, TX, USA; Henan Key Laboratory for Tumor Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
| | - Mutombo Kankonde
- Greater East Cancer Center & Coalition for the Reversal of Breast Cancer Mortality in African American Women , El Paso, TX, USA
| | - Peggy Kankonde
- Greater East Cancer Center & Coalition for the Reversal of Breast Cancer Mortality in African American Women , El Paso, TX, USA
| | - Bao-Fa Yu
- Beijing Baofa Tumor Hospital , Changping Dist, Beijing, China
| | - Jian-Ying Zhang
- The Academy of Medical Sciences, Zhengzhou University, Zhengzhou, Henan, China; Department of Biological Sciences, The University of Texas at El Paso, 500 W University Ave, El Paso, TX, USA; Henan Key Laboratory for Tumor Epidemiology, College of Public Health, Zhengzhou University, Zhengzhou, Henan, China
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30
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Histone deacetylase inhibition reveals a tumor-suppressive function of MYC-regulated miRNA in breast and lung carcinoma. Cell Death Differ 2016; 23:1312-21. [PMID: 26915294 DOI: 10.1038/cdd.2016.9] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/04/2015] [Accepted: 01/14/2016] [Indexed: 02/07/2023] Open
Abstract
Histone deacetylase (HDAC) inhibition leads to dynamic changes in the epigenetic landscape that is postulated to alter the expression of critical mediators of cellular proliferation and death. While current HDAC inhibitors have shown to be efficacious in the treatment of specific hematologic malignancies, their therapeutic utility in epithelial-based cancers warrants further evaluation. Moreover, the mechanisms of HDAC inhibition-induced cancer cell death are not completely understood. Therefore, elucidation of the underlying pathways engaged by HDAC inhibition may enable the development of more effective therapeutic strategies. Here, we report that HDAC inhibition in human breast and lung carcinoma cells activates an apoptotic mechanism mediated by microRNA (miRNA) and induced by the oncogene MYC. Specifically, following HDAC inhibition, MYC, which normally represses miR-15 and let-7 families, transcriptionally activated their expression and MYC was required for this miRNA upregulation. As a result, transcript levels of the tumor-suppressive miR-15 and let-7 families increased, which targeted and decreased the expression of the crucial prosurvival genes BCL-2 and BCL-XL, respectively. MYC was also required for the downregulation of BCL-2 and BCL-XL following HDAC inhibition. Blocking the binding sites of the miR-15 and let-7 families in the 3'-untranslated regions of BCL-2 and BCL-XL protected against HDAC inhibition-induced apoptosis. These results provide important insight into the molecular underpinnings of HDAC inhibition-induced cell death in breast and lung cancer and reveal a tumor-suppressive role for MYC-regulated miRNA that is activated with HDAC inhibition.
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31
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Patent Highlight. Pharm Pat Anal 2016. [DOI: 10.4155/ppa.15.37] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
A snapshot of noteworthy recent developments in the patent literature of relevance to pharmaceutical and medical research and development.
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Adams CM, Hiebert SW, Eischen CM. Myc Induces miRNA-Mediated Apoptosis in Response to HDAC Inhibition in Hematologic Malignancies. Cancer Res 2015; 76:736-48. [PMID: 26676759 DOI: 10.1158/0008-5472.can-15-1751] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 10/12/2015] [Indexed: 12/26/2022]
Abstract
Alterations in the expression or function of histone deacetylases (HDAC) contribute to the development and progression of hematologic malignancies. Consequently, the development and implementation of HDAC inhibitors has proven to be therapeutically beneficial, particularly for hematologic malignancies. However, the molecular mechanisms by which HDAC inhibition (HDACi) induces tumor cell death remain unresolved. Here, we investigated the effects of HDACi in Myc-driven B-cell lymphoma and five other hematopoietic malignancies. We determined that Myc-mediated transcriptional repression of the miR-15 and let-7 families in malignant cells was relieved upon HDACi, and Myc was required for their upregulation. The miR-15 and let-7 families then targeted and downregulated the antiapoptotic genes Bcl-2 and Bcl-xL, respectively, to induce HDACi-mediated apoptosis. Notably, Myc also transcriptionally upregulated these miRNA in untransformed cells, indicating that this Myc-induced miRNA-mediated apoptotic pathway is suppressed in malignant cells, but becomes reactivated upon HDACi. Taken together, our results reveal a previously unknown mechanism by which Myc induces apoptosis independent of the p53 pathway and as a response to HDACi in malignant hematopoietic cells.
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Affiliation(s)
- Clare M Adams
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Scott W Hiebert
- Department of Biochemistry, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee.
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Edmonds MD, Boyd KL, Moyo T, Mitra R, Duszynski R, Arrate MP, Chen X, Zhao Z, Blackwell TS, Andl T, Eischen CM. MicroRNA-31 initiates lung tumorigenesis and promotes mutant KRAS-driven lung cancer. J Clin Invest 2015; 126:349-64. [PMID: 26657862 DOI: 10.1172/jci82720] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2015] [Accepted: 11/06/2015] [Indexed: 01/12/2023] Open
Abstract
MicroRNA (miR) are important regulators of gene expression, and aberrant miR expression has been linked to oncogenesis; however, little is understood about their contribution to lung tumorigenesis. Here, we determined that miR-31 is overexpressed in human lung adenocarcinoma and this overexpression independently correlates with decreased patient survival. We developed a transgenic mouse model that allows for lung-specific expression of miR-31 to test the oncogenic potential of miR-31 in the lung. Using this model, we observed that miR-31 induction results in lung hyperplasia, followed by adenoma formation and later adenocarcinoma development. Moreover, induced expression of miR-31 in mice cooperated with mutant KRAS to accelerate lung tumorigenesis. We determined that miR-31 regulates lung epithelial cell growth and identified 6 negative regulators of RAS/MAPK signaling as direct targets of miR-31. Our study distinguishes miR-31 as a driver of lung tumorigenesis that promotes mutant KRAS-mediated oncogenesis and reveals that miR-31 directly targets and reduces expression of negative regulators of RAS/MAPK signaling.
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Lu S, Zhou W, Wei H, He L, Li L. MTBP Promotes the Invasion and Metastasis of Hepatocellular Carcinoma by Enhancing the MDM2-Mediated Degradation of E-Cadherin. Dig Dis Sci 2015; 60:3681-90. [PMID: 26280083 DOI: 10.1007/s10620-015-3824-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2015] [Accepted: 07/22/2015] [Indexed: 12/13/2022]
Abstract
BACKGROUND Emerging evidence suggests that MTBP plays a role in cancer development and possibly progression, but its influence on hepatocellular carcinoma (HCC) remains unclear. METHODS We used real-time PCR and Western blotting to investigate MTBP expression in four HCC cell lines, 120 pairs of tumor and corresponding paracarcinomatous tissues from HCC patients. Immunohistochemistry was performed to examine MTBP expression in HCC and corresponding paracarcinomatous tissues from 120 patients. E-cadherin was only examined in HCC tissues of patients mentioned above. Statistical analyses were applied to evaluate the prognostic value and associations of MTBP expression with clinical parameters. Furthermore, the MTBP gene was overexpressed in HepG2 cell and silenced by siRNA in Hu7 cell, and cell migration and invasion were detected in vitro and in vivo. Moreover, the molecular mechanism of E-cadherin regulation by MTBP was explored. RESULTS In this study, we first showed that MTBP protein expression is positively correlated with distant metastasis and poor prognosis in HCC patients. We also found that MTBP expression was increased in metastatic cell lines when compared with nonmetastatic cell lines. Consistent with these findings, enhanced expression of MTBP promoted HCC cell invasiveness and metastasis both in vitro and in vivo, whereas the knockdown of MTBP with small interfering RNA resulted in reduced HCC migration and invasion. Ectopic expression of MTBP in HCC cells induced epithelial-to-mesenchymal transition, whereas the silencing of MTBP had the opposite effect. Furthermore, our results show that MTBP and E-cadherin protein expression are inversely correlated in primary HCC tissues. Moreover, our findings indicate that MTBP overexpression decreases E-cadherin expression through the modulation of Mdm2 ubiquitination degradation. CONCLUSIONS Our data show that MTBP aggravates the invasion and metastasis of HCC by promoting the MDM2-mediated degradation of E-cadherin.
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Affiliation(s)
- Shan Lu
- Department of Gastroenterology, Second Affiliated Hospital of Nanchang University, Nanchang, 330006, China. .,Department of Oncology, Jiangxi Provincial Cancer Hospital, Nanchang, 330029, China. .,Jiangxi Province Key Laboratory of Molecular Medicine, Nanchang, 330006, China.
| | - Wei Zhou
- Department of Gastrointestinal Surgery, Jiangxi Provincial Cancer Hospital, Nanchang, 330029, China
| | - Haiyun Wei
- Department of Gastrointestinal Surgery, Jiangxi Provincial Cancer Hospital, Nanchang, 330029, China
| | - Leifeng He
- Jiangxi Province Key Laboratory of Molecular Medicine, Nanchang, 330006, China
| | - Liang Li
- Jiangxi Province Key Laboratory of Molecular Medicine, Nanchang, 330006, China
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Bi Q, Ranjan A, Fan R, Agarwal N, Welch DR, Weinman SA, Ding J, Iwakuma T. MTBP inhibits migration and metastasis of hepatocellular carcinoma. Clin Exp Metastasis 2015; 32:301-11. [PMID: 25759210 DOI: 10.1007/s10585-015-9706-5] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2014] [Accepted: 02/07/2015] [Indexed: 01/08/2023]
Abstract
Hepatocellular carcinoma (HCC) is one of the most common cancers worldwide with increasing incidence. Despite curative surgical resection and advanced chemotherapy, its survival rate remains low. The presence of microvascular invasion and occult metastasis is one of the major causes for this poor outcome. MDM2 Binding Protein (MTBP) has been implicated in the suppression of cell migration and cancer metastasis. However, clinical significance of MTBP, particularly in human cancer, is poorly understood. Specifically, clinical relevance of MTBP in human HCC has never been investigated. Here we demonstrated that expression of MTBP was significantly reduced in human HCC tissues compared to adjacent non-tumor tissues. MTBP expression was negatively correlated with capsular/vascular invasion and lymph node metastasis. Overexpression of MTBP resulted in the suppression of the migratory and metastatic potential of HCC cells, while its downregulation increased the migration. Consistent with the previous report, MTBP endogenously bound to alpha-actinin 4 (ACTN4) and suppressed ACTN4-mediated cell migration in multiple HCC cell lines. However, MTBP also inhibited migratory potential of PLC/PRF/5 HCC cells whose migration was not altered by manipulation of ACTN4 expression. These results suggest that mechanisms behind MTBP-mediated migration suppression may not be limited to the pathway involving ACTN4 in certain cellular contexts. Additionally, as a potential mechanism for reduced MTBP expression in tumors, we found that MTBP expression was increased following the treatment with histone deacetylase inhibitors (HDIs). Our study, for the first time, provides clinical relevance of MTBP in the suppression of HCC metastasis.
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Affiliation(s)
- Qian Bi
- Diagnosis and Treatment Center for Liver Cirrhosis, 302 Military Hospital of China, Beijing, 10039, People's Republic of China
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Zegerman P. Evolutionary conservation of the CDK targets in eukaryotic DNA replication initiation. Chromosoma 2015; 124:309-21. [PMID: 25575982 DOI: 10.1007/s00412-014-0500-y] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2014] [Revised: 11/27/2014] [Accepted: 12/01/2014] [Indexed: 10/24/2022]
Abstract
A fundamental requirement for all organisms is the faithful duplication and transmission of the genetic material. Failure to accurately copy and segregate the genome during cell division leads to loss of genetic information and chromosomal abnormalities. Such genome instability is the hallmark of the earliest stages of tumour formation. Cyclin-dependent kinase (CDK) plays a vital role in regulating the duplication of the genome within the eukaryotic cell cycle. Importantly, this kinase is deregulated in many cancer types and is an emerging target of chemotherapeutics. In this review, I will consider recent advances concerning the role of CDK in replication initiation across eukaryotes. The implications for strict CDK-dependent regulation of genome duplication in the context of the cell cycle will be discussed.
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Affiliation(s)
- Philip Zegerman
- Department of Biochemistry, Wellcome Trust/Cancer Research UK Gurdon Institute, University of Cambridge, The Henry Wellcome Building of Cancer and Developmental Biology, Cambridge, CB2 1QN, UK,
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Grieb BC, Chen X, Eischen CM. MTBP is overexpressed in triple-negative breast cancer and contributes to its growth and survival. Mol Cancer Res 2014; 12:1216-24. [PMID: 24866769 PMCID: PMC4163510 DOI: 10.1158/1541-7786.mcr-14-0069] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
UNLABELLED Triple-negative breast cancer (TNBC) is a clinically aggressive subtype of breast cancer commonly resistant to therapeutics that have been successful in increasing survival in patients with estrogen receptor-positive (ER(+)) and HER2(+) breast cancer. As such, identifying factors that contribute to poor patient outcomes and mediate the growth and survival of TNBC cells remain important areas of investigation. MTBP (MDM2-binding protein), a gene linked to cellular proliferation and a transcriptional target of the MYC oncogene, is overexpressed in human malignancies, yet its contribution to cancer remains unresolved. Evaluation of mRNA expression and copy number variation data from The Cancer Genome Atlas (TCGA) revealed that MTBP is commonly overexpressed in breast cancer and 19% show amplification of MTBP. Increased transcript or gene amplification of MTBP significantly correlated with reduced breast cancer patient survival. Further analysis revealed that while MTBP mRNA is overexpressed in both ER(+) and HER2(+) breast cancers, its expression is highest in TNBC. MTBP mRNA and protein levels were also significantly elevated in a panel of human TNBC cell lines. Knockdown of MTBP in TNBC cells induced apoptosis and significantly reduced TNBC cell growth and soft agar colony formation, which was rescued by expression of shRNA-resistant Mtbp. Notably, inducible knockdown of MTBP expression significantly impaired TNBC tumor growth, in vivo, including in established tumors. Thus, these data emphasize that MTBP is important for the growth and survival of TNBC and warrants further investigation as a potential novel therapeutic target. IMPLICATIONS MTBP significantly contributes to breast cancer survival and is a potential novel therapeutic target in TNBC.
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Affiliation(s)
- Brian C Grieb
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Xi Chen
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, Tennessee
| | - Christine M Eischen
- Department of Pathology, Microbiology and Immunology, Vanderbilt University Medical Center, Nashville, Tennessee.
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