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Provasek VE, Bacolla A, Rangaswamy S, Mitra J, Kodavati M, Yusuf IO, Malojirao VH, Vasquez V, Britz GW, Li GM, Xu Z, Mitra S, Garruto RM, Tainer JA, Hegde ML. RNA/DNA Binding Protein TDP43 Regulates DNA Mismatch Repair Genes with Implications for Genome Stability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.16.594552. [PMID: 38798341 PMCID: PMC11118483 DOI: 10.1101/2024.05.16.594552] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2024]
Abstract
TDP43 is an RNA/DNA binding protein increasingly recognized for its role in neurodegenerative conditions including amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). As characterized by its aberrant nuclear export and cytoplasmic aggregation, TDP43 proteinopathy is a hallmark feature in over 95% of ALS/FTD cases, leading to the formation of detrimental cytosolic aggregates and a reduction in nuclear functionality within neurons. Building on our prior work linking TDP43 proteinopathy to the accumulation of DNA double-strand breaks (DSBs) in neurons, the present investigation uncovers a novel regulatory relationship between TDP43 and DNA mismatch repair (MMR) gene expressions. Here, we show that TDP43 depletion or overexpression directly affects the expression of key MMR genes. Alterations include MLH1, MSH2, MSH3, MSH6, and PMS2 levels across various primary cell lines, independent of their proliferative status. Our results specifically establish that TDP43 selectively influences the expression of MLH1 and MSH6 by influencing their alternative transcript splicing patterns and stability. We furthermore find aberrant MMR gene expression is linked to TDP43 proteinopathy in two distinct ALS mouse models and post-mortem brain and spinal cord tissues of ALS patients. Notably, MMR depletion resulted in the partial rescue of TDP43 proteinopathy-induced DNA damage and signaling. Moreover, bioinformatics analysis of the TCGA cancer database reveals significant associations between TDP43 expression, MMR gene expression, and mutational burden across multiple cancers. Collectively, our findings implicate TDP43 as a critical regulator of the MMR pathway and unveil its broad impact on the etiology of both neurodegenerative and neoplastic pathologies.
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Affiliation(s)
- Vincent E Provasek
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- School of Medicine, Texas A&M University, College Station, TX 77843, USA
| | - Albino Bacolla
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Suganya Rangaswamy
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Joy Mitra
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Manohar Kodavati
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Issa O Yusuf
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Vikas H Malojirao
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Velmarini Vasquez
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Gavin W Britz
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Neurosurgery and Department of Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
| | - Guo-Min Li
- Department of Radiation Oncology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Zuoshang Xu
- Department of Biochemistry and Molecular Biotechnology, University of Massachusetts Chan Medical School, Worcester, MA, 01655, USA
| | - Sankar Mitra
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
| | - Ralph M Garruto
- Department of Biological Sciences, Binghamton University, State University of New York, Binghamton, NY 13902
| | - John A Tainer
- Department of Molecular and Cellular Oncology, Department of Cancer Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - Muralidhar L Hegde
- Division of DNA Repair Research within the Center for Neuroregeneration, Department of Neurosurgery, Houston Methodist Research Institute, Houston, TX 77030, USA
- Department of Neuroscience, Weill Cornell Medical College, New York, NY 10065, USA
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Therapeutic Potential of PARP Inhibitors in the Treatment of Gastrointestinal Cancers. Biomedicines 2021; 9:biomedicines9081024. [PMID: 34440228 PMCID: PMC8392860 DOI: 10.3390/biomedicines9081024] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/05/2021] [Accepted: 08/10/2021] [Indexed: 12/20/2022] Open
Abstract
Gastrointestinal (GI) malignancies are a major global health burden, with high mortality rates. The identification of novel therapeutic strategies is crucial to improve treatment and survival of patients. The poly (ADP-ribose) polymerase (PARP) enzymes involved in the DNA damage response (DDR) play major roles in the development, progression and treatment response of cancer, with PARP inhibitors (PARPi) currently used in the clinic for breast, ovarian, fallopian, primary peritoneal, pancreatic and prostate cancers with deficiencies in homologous recombination (HR) DNA repair. This article examines the current evidence for the role of the DDR PARP enzymes (PARP1, 2, 3 and 4) in the development, progression and treatment response of GI cancers. Furthermore, we discuss the role of HR status as a predictive biomarker of PARPi efficacy in GI cancer patients and examine the pre-clinical and clinical evidence for PARPi and cytotoxic therapy combination strategies in GI cancer. We also include an analysis of the genomic and transcriptomic landscape of the DDR PARP genes and key HR genes (BRCA1, BRCA2, ATM, RAD51, MRE11, PALB2) in GI patient tumours (n = 1744) using publicly available datasets to identify patients that may benefit from PARPi therapeutic approaches.
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Ortíz R, Quiñonero F, García-Pinel B, Fuel M, Mesas C, Cabeza L, Melguizo C, Prados J. Nanomedicine to Overcome Multidrug Resistance Mechanisms in Colon and Pancreatic Cancer: Recent Progress. Cancers (Basel) 2021; 13:2058. [PMID: 33923200 PMCID: PMC8123136 DOI: 10.3390/cancers13092058] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 04/22/2021] [Accepted: 04/22/2021] [Indexed: 12/24/2022] Open
Abstract
The development of drug resistance is one of the main causes of cancer treatment failure. This phenomenon occurs very frequently in different types of cancer, including colon and pancreatic cancers. However, the underlying molecular mechanisms are not fully understood. In recent years, nanomedicine has improved the delivery and efficacy of drugs, and has decreased their side effects. In addition, it has allowed to design drugs capable of avoiding certain resistance mechanisms of tumors. In this article, we review the main resistance mechanisms in colon and pancreatic cancers, along with the most relevant strategies offered by nanodrugs to overcome this obstacle. These strategies include the inhibition of efflux pumps, the use of specific targets, the development of nanomedicines affecting the environment of cancer-specific tissues, the modulation of DNA repair mechanisms or RNA (miRNA), and specific approaches to damage cancer stem cells, among others. This review aims to illustrate how advanced nanoformulations, including polymeric conjugates, micelles, dendrimers, liposomes, metallic and carbon-based nanoparticles, are allowing to overcome one of the main limitations in the treatment of colon and pancreatic cancers. The future development of nanomedicine opens new horizons for cancer treatment.
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Affiliation(s)
- Raúl Ortíz
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Francisco Quiñonero
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Beatriz García-Pinel
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Marco Fuel
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Cristina Mesas
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Laura Cabeza
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Consolación Melguizo
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
| | - Jose Prados
- Institute of Biopathology and Regenerative Medicine (IBIMER), Center of Biomedical Research (CIBM), University of Granada, 18100 Granada, Spain; (R.O.); (F.Q.); (B.G.-P.); (M.F.); (C.M.); (L.C.); (J.P.)
- Department of Anatomy and Embriology, Faculty of Medicine, University of Granada, 18071 Granada, Spain
- Instituto Biosanitario de Granada (ibs.GRANADA), 18014 Granada, Spain
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Mirza-Aghazadeh-Attari M, Darband SG, Kaviani M, Mihanfar A, Aghazadeh Attari J, Yousefi B, Majidinia M. DNA damage response and repair in colorectal cancer: Defects, regulation and therapeutic implications. DNA Repair (Amst) 2018; 69:34-52. [PMID: 30055507 DOI: 10.1016/j.dnarep.2018.07.005] [Citation(s) in RCA: 43] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Revised: 07/15/2018] [Accepted: 07/15/2018] [Indexed: 12/11/2022]
Abstract
DNA damage response, a key factor involved in maintaining genome integrity and stability, consists of several kinase-dependent signaling pathways, which sense and transduce DNA damage signal. The severity of damage appears to determine DNA damage responses, which can include cell cycle arrest, damage repair and apoptosis. A number of recent studies have demonstrated that defection in signaling through this network is thought to be an underlying mechanism behind the development and progression of various types of human malignancies, including colorectal cancer. In this review, colorectal cancer and its molecular pathology as well as DNA damage response is briefly introduced. Finally, the involvement of key components of this network in the initiation/progression, prognosis, response to treatment and development of drug resistance is comprehensively discussed.
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Affiliation(s)
- Mohammad Mirza-Aghazadeh-Attari
- Aging Research Institute, Tabriz University of Medical Sciences, Tabriz, Iran; Student Research Committee, Tabriz University of Medical Sciences, Tabriz, Iran
| | - Saber Ghazizadeh Darband
- Danesh Pey Hadi Co., Health Technology Development Center, Urmia University of Medical Sciences, Urmia, Iran
| | - Mojtaba Kaviani
- School of Nutrition and Dietetics, Acadia University, Wolfville, Nova Scotia, Canada
| | - Ainaz Mihanfar
- Stem Cell and Regenerative Medicine Institute, Tabriz University of Medical Sciences, Tabriz, Iran
| | | | - Bahman Yousefi
- Molecular Medicine Research Center, Tabriz University of Medical Sciences, Tabriz, Iran; Immunology Research Center, Tabriz University of Medical Sciences, Tabriz, Iran.
| | - Maryam Majidinia
- Solid Tumor Research Center, Urmia University of Medical Sciences, Urmia, Iran.
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Tang W, Liu X, Qiu L, Zhao X, Huang M, Yin J, Li J, Guo W, Zhu X, Chen Z. Influence of hypoxia-related genetic polymorphisms on the prognosis of patients with metastatic gastric cancer treated with EOF. Oncol Lett 2017; 15:1334-1342. [PMID: 29399184 DOI: 10.3892/ol.2017.7414] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 09/01/2017] [Indexed: 11/06/2022] Open
Abstract
Tumor hypoxia is common in a number of solid tumor types including gastric cancer, and is associated with treatment resistance and poor prognosis. The present study aimed to investigate the function of hypoxia-associated genetic polymorphisms in predicting treatment response and survival in patients with metastatic gastric cancer (MGC) treated with EOF (oxaliplatin and 5-fluorouracil combined with epirubicin) as first-line chemotherapy. The present retrospective study enrolled 108 Chinese patients with MGC receiving EOF as first-line chemotherapy, and genotyped six single nucleotide polymorphisms (SNPs) in four hypoxia-associated genes [myoglobin (MB) rs7292 and rs7293, ATP Binding Cassette Subfamily G Member 2 rs2231142, MutL homolog 1 (MLH1) rs1800734 and rs9852810, and Poly(ADP-Ribose) Polymerase 1 rs1136410]. The results of the present study indicated that the CT/TT genotype of MB rs7292, as well as the GG genotype of MLH1 rs9852810, were independent favorable predictive factors of progression-free survival [PFS; MB rs7292: hazard ratio (HR)=0.135, 95% confidence interval (CI)=0.057-0.321, P<0.001; MLH1 rs9852810: HR=0.494, 95% CI=0.267-0.913, P=0.024). Using a prognostic index based on the favorable SNPs for PFS (MB rs7292 CT/TT genotype, and MLH1 rs9852810 GG genotype), patients were classified into a low-risk group (involving one or two of the two SNPs) and a high-risk group (involving neither of the two SNPs), with a PFS of 180.0 and 117.0 days, respectively (P=0.002). The results of the present study demonstrated that the CT/TT genotype of MB rs7292 and the GG genotype of MLH1 rs9852810 were independent favorable predictive factors of PFS in patients with MGC treated with EOF. Identification of those SNPs in blood samples may allow for the prediction of the short-term efficacy of first-line EOF treatment in patients with MGC.
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Affiliation(s)
- Wenbo Tang
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Xin Liu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Lixin Qiu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Xiaoying Zhao
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Mingzhu Huang
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Jiliang Yin
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Jin Li
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Weijian Guo
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Xiaodong Zhu
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
| | - Zhiyu Chen
- Department of Medical Oncology, Fudan University Shanghai Cancer Center, Shanghai 200032, P.R. China.,Department of Oncology, Shanghai Medical College, Fudan University, Shanghai 200032, P.R. China
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Cohen PR, Tomson BN, Elkin SK, Marchlik E, Carter JL, Kurzrock R. Genomic portfolio of Merkel cell carcinoma as determined by comprehensive genomic profiling: implications for targeted therapeutics. Oncotarget 2016; 7:23454-67. [PMID: 26981779 PMCID: PMC5029639 DOI: 10.18632/oncotarget.8032] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2016] [Accepted: 02/28/2016] [Indexed: 12/22/2022] Open
Abstract
Merkel cell carcinoma is an ultra-rare cutaneous neuroendocrine cancer for which approved treatment options are lacking. To better understand potential actionability, the genomic landscape of Merkel cell cancers was assessed. The molecular aberrations in 17 patients with Merkel cell carcinoma were, on physician request, tested in a Clinical Laboratory Improvement Amendments (CLIA) laboratory (Foundation Medicine, Cambridge, MA) using next-generation sequencing (182 or 236 genes) and analyzed by N-of-One, Inc. (Lexington, MA). There were 30 genes harboring aberrations and 60 distinct molecular alterations identified in this patient population. The most common abnormalities involved the TP53 gene (12/17 [71% of patients]) and the cell cycle pathway (CDKN2A/B, CDKN2C or RB1) (12/17 [71%]). Abnormalities also were observed in the PI3K/AKT/mTOR pathway (AKT2, FBXW7, NF1, PIK3CA, PIK3R1, PTEN or RICTOR) (9/17 [53%]) and DNA repair genes (ATM, BAP1, BRCA1/2, CHEK2, FANCA or MLH1) (5/17 [29%]). Possible cognate targeted therapies, including FDA-approved drugs, could be identified in most of the patients (16/17 [94%]). In summary, Merkel cell carcinomas were characterized by multiple distinct aberrations that were unique in the majority of analyzed cases. Most patients had theoretically actionable alterations. These results provide a framework for investigating tailored combinations of matched therapies in Merkel cell carcinoma patients.
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Affiliation(s)
- Philip R. Cohen
- Department of Dermatology, University of California San Diego, San Diego, CA, USA
| | | | | | | | | | - Razelle Kurzrock
- Center for Personalized Cancer Therapy and Division of Hematology and Oncology, Department of Medicine, University of California San Diego Moores Cancer Center, San Diego, CA, USA
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Graham DM, Coyle VM, Kennedy RD, Wilson RH. Molecular Subtypes and Personalized Therapy in Metastatic Colorectal Cancer. CURRENT COLORECTAL CANCER REPORTS 2016; 12:141-150. [PMID: 27340376 PMCID: PMC4879165 DOI: 10.1007/s11888-016-0312-y] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Development of colorectal cancer occurs via a number of key pathways, with the clinicopathological features of specific subgroups being driven by underlying molecular changes. Mutations in key genes within the network of signalling pathways have been identified; however, therapeutic strategies to target these aberrations remain limited. As understanding of the biology of colorectal cancer has improved, this has led to a move toward broader genomic testing, collaborative research and innovative, adaptive clinical trial design. Recent developments in therapy include the routine adoption of wider mutational spectrum testing prior to use of targeted therapies and the first promise of effective immunotherapy for colorectal cancer patients. This review details current biomarkers in colorectal cancer for molecular stratification and for treatment allocation purposes, including open and planned precision medicine trials. Advances in our understanding, therapeutic strategy and technology will also be outlined.
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Affiliation(s)
- Donna M. Graham
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7AE N. Ireland UK
| | - Vicky M. Coyle
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7AE N. Ireland UK
| | - Richard D. Kennedy
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7AE N. Ireland UK
| | - Richard H. Wilson
- Centre for Cancer Research and Cell Biology, Queen’s University Belfast, 97 Lisburn Road, Belfast, BT9 7AE N. Ireland UK
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Tesauro C, Graziani G, Arnò B, Zuccaro L, Muzi A, D'Annessa I, Santori E, Tentori L, Leonetti C, Fiorani P, Desideri A. Mutations of human DNA topoisomerase I at poly(ADP-ribose) binding sites: modulation of camptothecin activity by ADP-ribose polymers. JOURNAL OF EXPERIMENTAL & CLINICAL CANCER RESEARCH : CR 2014; 33:71. [PMID: 25227992 PMCID: PMC4172901 DOI: 10.1186/s13046-014-0071-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/17/2014] [Accepted: 08/19/2014] [Indexed: 12/02/2022]
Abstract
Background DNA topoisomerases are key enzymes that modulate the topological state of DNA through the breaking and rejoining of DNA strands. Human topoisomerase I belongs to the family of poly(ADP-ribose)-binding proteins and is the target of camptothecin derived anticancer drugs. Poly(ADP-ribosyl)ation occurs at specific sites of the enzyme inhibiting the cleavage and enhancing the religation steps during the catalytic cycle. Thus, ADP-ribose polymers antagonize the activity of topoisomerase I poisons, whereas PARP inhibitors increase their antitumor effects. Methods Using site-directed mutagenesis we have analyzed the interaction of human topoisomerase I and poly(ADP-ribose) through enzymatic activity and binding procedures. Results Mutations of the human topoisomerase I hydrophobic or charged residues, located on the putative polymer binding sites, are not sufficient to abolish or reduce the binding of the poly(ADP-ribose) to the protein. These results suggest either the presence of additional binding sites or that the mutations are not enough perturbative to destroy the poly(ADP-ribose) interaction, although in one mutant they fully abolish the enzyme activity. Conclusions It can be concluded that mutations at the hydrophobic or charged residues of the putative polymer binding sites do not interfere with the ability of poly(ADP-ribose) to antagonize the antitumor activity of topoisomerase I poisons.
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Tentori L, Ricci-Vitiani L, Muzi A, Ciccarone F, Pelacchi F, Calabrese R, Runci D, Pallini R, Caiafa P, Graziani G. Pharmacological inhibition of poly(ADP-ribose) polymerase-1 modulates resistance of human glioblastoma stem cells to temozolomide. BMC Cancer 2014; 14:151. [PMID: 24593254 PMCID: PMC3975727 DOI: 10.1186/1471-2407-14-151] [Citation(s) in RCA: 56] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2013] [Accepted: 02/26/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Chemoresistance of glioblastoma multiforme (GBM) has been attributed to the presence within the tumor of cancer stem cells (GSCs). The standard therapy for GBM consists of surgery followed by radiotherapy and the chemotherapeutic agent temozolomide (TMZ). However, TMZ efficacy is limited by O6-methylguanine-DNA-methyltransferase (MGMT) and Mismatch Repair (MMR) functions. Strategies to counteract TMZ resistance include its combination with poly(ADP-ribose) polymerase inhibitors (PARPi), which hamper the repair of N-methylpurines. PARPi are also investigated as monotherapy for tumors with deficiency of homologous recombination (HR). We have investigated whether PARPi may restore GSC sensitivity to TMZ or may be effective as monotherapy. METHODS Ten human GSC lines were assayed for MMR proteins, MGMT and PARP-1 expression/activity, MGMT promoter methylation and sensitivity to TMZ or PARPi, alone and in combination. Since PTEN defects are frequently detected in GBM and may cause HR dysfunction, PTEN expression was also analyzed. The statistical analysis of the differences in drug sensitivity among the cell lines was performed using the ANOVA and Bonferroni's post-test or the non-parametric Kruskal-Wallis analysis and Dunn's post-test for multiple comparisons. Synergism between TMZ and PARPi was analyzed by the median-effect method of Chou and Talalay. Correlation analyses were done using the Spearman's rank test. RESULTS All GSCs were MMR-proficient and resistance to TMZ was mainly associated with high MGMT activity or low proliferation rate. MGMT promoter hypermethylation of GSCs correlated both with low MGMT activity/expression (Spearman's test, P = 0.004 and P = 0.01) and with longer overall survival of GBM patients (P = 0.02). Sensitivity of each GSC line to PARPi as single agent did not correlate with PARP-1 or PTEN expression. Notably, PARPi and TMZ combination exerted synergistic antitumor effects in eight out of ten GSC lines and the TMZ dose reduction achieved significantly correlated with the sensitivity of each cell line to PARPi as single agent (P = 0.01). CONCLUSIONS The combination of TMZ with PARPi may represent a valuable strategy to reverse GSC chemoresistance.
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Affiliation(s)
- Lucio Tentori
- Department of System Medicine, University of Rome "Tor Vergata", Via Montpellier 1, 00133 Rome, Italy.
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