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Fujii S, Fuchs RP. Accidental Encounter of Repair Intermediates in Alkylated DNA May Lead to Double-Strand Breaks in Resting Cells. Int J Mol Sci 2024; 25:8192. [PMID: 39125763 PMCID: PMC11311527 DOI: 10.3390/ijms25158192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2024] [Revised: 07/24/2024] [Accepted: 07/25/2024] [Indexed: 08/12/2024] Open
Abstract
In clinics, chemotherapy is often combined with surgery and radiation to increase the chances of curing cancers. In the case of glioblastoma (GBM), patients are treated with a combination of radiotherapy and TMZ over several weeks. Despite its common use, the mechanism of action of the alkylating agent TMZ has not been well understood when it comes to its cytotoxic effects in tumor cells that are mostly non-dividing. The cellular response to alkylating DNA damage is operated by an intricate protein network involving multiple DNA repair pathways and numerous checkpoint proteins that are dependent on the type of DNA lesion, the cell type, and the cellular proliferation state. Among the various alkylating damages, researchers have placed a special on O6-methylguanine (O6-mG). Indeed, this lesion is efficiently removed via direct reversal by O6-methylguanine-DNA methyltransferase (MGMT). As the level of MGMT expression was found to be directly correlated with TMZ efficiency, O6-mG was identified as the critical lesion for TMZ mode of action. Initially, the mode of action of TMZ was proposed as follows: when left on the genome, O6-mG lesions form O6-mG: T mispairs during replication as T is preferentially mis-inserted across O6-mG. These O6-mG: T mispairs are recognized and tentatively repaired by a post-replicative mismatched DNA correction system (i.e., the MMR system). There are two models (futile cycle and direct signaling models) to account for the cytotoxic effects of the O6-mG lesions, both depending upon the functional MMR system in replicating cells. Alternatively, to explain the cytotoxic effects of alkylating agents in non-replicating cells, we have proposed a "repair accident model" whose molecular mechanism is dependent upon crosstalk between the MMR and the base excision repair (BER) systems. The accidental encounter between these two repair systems will cause the formation of cytotoxic DNA double-strand breaks (DSBs). In this review, we summarize these non-exclusive models to explain the cytotoxic effects of alkylating agents and discuss potential strategies to improve the clinical use of alkylating agents.
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Affiliation(s)
- Shingo Fujii
- Cancer Research Center of Marseille, Department of Genome Integrity, CNRS UMR7258, Inserm U1068, Institut Paoli-Calmettes, Aix Marseille University, 13273 Marseille, France
| | - Robert P. Fuchs
- SAS bioHalosis, Zone Luminy Biotech, 13009 Marseille, France
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Smerdi D, Moutafi M, Kotsantis I, Stavrinou LC, Psyrri A. Overcoming Resistance to Temozolomide in Glioblastoma: A Scoping Review of Preclinical and Clinical Data. Life (Basel) 2024; 14:673. [PMID: 38929657 PMCID: PMC11204771 DOI: 10.3390/life14060673] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2024] [Revised: 05/15/2024] [Accepted: 05/17/2024] [Indexed: 06/28/2024] Open
Abstract
Glioblastoma (GB) is the most common and most aggressive primary brain tumor in adults, with an overall survival almost 14.6 months. Optimal resection followed by combined temozolomide chemotherapy and radiotherapy, also known as Stupp protocol, remains the standard of treatment; nevertheless, resistance to temozolomide, which can be obtained throughout many molecular pathways, is still an unsurpassed obstacle. Several factors influence the efficacy of temozolomide, including the involvement of other DNA repair systems, aberrant signaling pathways, autophagy, epigenetic modifications, microRNAs, and extracellular vesicle production. The blood-brain barrier, which serves as both a physical and biochemical obstacle, the tumor microenvironment's pro-cancerogenic and immunosuppressive nature, and tumor-specific characteristics such as volume and antigen expression, are the subject of ongoing investigation. In this review, preclinical and clinical data about temozolomide resistance acquisition and possible ways to overcome chemoresistance, or to treat gliomas without restoration of chemosensitinity, are evaluated and presented. The objective is to offer a thorough examination of the clinically significant molecular mechanisms and their intricate interrelationships, with the aim of enhancing understanding to combat resistance to TMZ more effectively.
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Affiliation(s)
- Dimitra Smerdi
- Department of Medical Oncology, Second Department of Internal Medicine, “Attikon” University General Hospital, Athens Medical School, National and Kapodistrian University of Athens, 11528 Athens, Greece
| | - Myrto Moutafi
- Department of Medical Oncology, Second Department of Internal Medicine, “Attikon” University General Hospital, Athens Medical School, National and Kapodistrian University of Athens, 11528 Athens, Greece
| | - Ioannis Kotsantis
- Department of Medical Oncology, Second Department of Internal Medicine, “Attikon” University General Hospital, Athens Medical School, National and Kapodistrian University of Athens, 11528 Athens, Greece
| | - Lampis C. Stavrinou
- Department of Neurosurgery and Neurotraumatology, “Attikon” University General Hospital, Athens Medical School, National and Kapodistrian University of Athens, 12462 Athens, Greece
| | - Amanda Psyrri
- Department of Medical Oncology, Second Department of Internal Medicine, “Attikon” University General Hospital, Athens Medical School, National and Kapodistrian University of Athens, 11528 Athens, Greece
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3
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Ganesa S, Sule A, Sundaram RK, Bindra RS. Mismatch repair proteins play a role in ATR activation upon temozolomide treatment in MGMT-methylated glioblastoma. Sci Rep 2022; 12:5827. [PMID: 35388070 PMCID: PMC8987098 DOI: 10.1038/s41598-022-09614-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2021] [Accepted: 03/22/2022] [Indexed: 12/20/2022] Open
Abstract
The methylation status of the O6-methylguanine methyltransferase (MGMT) gene promoter has been widely accepted as a prognostic biomarker for treatment with the alkylator, temozolomide (TMZ). In the absence of promoter methylation, the MGMT enzyme removes O6-methylguanine (O6-meG) lesions. In the setting of MGMT-promoter methylation (MGMT-), the O6-meG lesion activates the mismatch repair (MMR) pathway which functions to remove the damage. Our group reported that loss of MGMT expression via MGMT promoter silencing modulates activation of ataxia telangiectasia and RAD3 related protein (ATR) in response to TMZ treatment, which is associated with synergistic tumor-cell killing. Whether or not MMR proteins are involved in ATR activation in MGMT-cells upon alkylation damage remains poorly understood. To investigate the function of MMR in ATR activation, we created isogenic cell lines with knockdowns of the individual human MMR proteins MutS homolog 2 (MSH2), MutS homolog 6 (MSH6), MutS homolog 3 (MSH3), MutL homolog 1 (MLH1), and PMS1 homolog 2 (PMS2). Here, we demonstrate that MSH2, MSH6, MLH1 and PMS2, specifically, are involved in the activation of the ATR axis after TMZ exposure, whereas MSH3 is likely not. This study elucidates a potential mechanistic understanding of how the MMR system is involved in ATR activation by TMZ in glioblastoma cells, which is important for targeting MMR-mutated cancers.
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Affiliation(s)
- Sachita Ganesa
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06511, USA
| | - Amrita Sule
- Department of Therapeutic Radiology, Yale University, 333 Cedar Street, New Haven, CT, 06511, USA
| | - Ranjini K Sundaram
- Department of Therapeutic Radiology, Yale University, 333 Cedar Street, New Haven, CT, 06511, USA
| | - Ranjit S Bindra
- Department of Therapeutic Radiology, Yale University, 333 Cedar Street, New Haven, CT, 06511, USA.
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Fujii S, Sobol RW, Fuchs RP. Double-Strand Breaks: when DNA Repair Events Accidentally Meet. DNA Repair (Amst) 2022; 112:103303. [PMID: 35219626 PMCID: PMC8898275 DOI: 10.1016/j.dnarep.2022.103303] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2021] [Revised: 01/23/2022] [Accepted: 02/17/2022] [Indexed: 01/26/2023]
Abstract
The cellular response to alkylation damage is complex, involving multiple DNA repair pathways and checkpoint proteins, depending on the DNA lesion, the cell type, and the cellular proliferation state. The repair of and response to O-alkylation damage, primarily O6-methylguaine DNA adducts (O6-mG), is the purview of O6-methylguanine-DNA methyltransferase (MGMT). Alternatively, this lesion, if left un-repaired, induces replication-dependent formation of the O6-mG:T mis-pair and recognition of this mis-pair by the post-replication mismatch DNA repair pathway (MMR). Two models have been suggested to account for MMR and O6-mG DNA lesion dependent formation of DNA double-strand breaks (DSBs) and the resulting cytotoxicity - futile cycling and direct DNA damage signaling. While there have been hints at crosstalk between the MMR and base excision repair (BER) pathways, clear mechanistic evidence for such pathway coordination in the formation of DSBs has remained elusive. However, using a novel protein capture approach, Fuchs and colleagues have demonstrated that DSBs result from an encounter between MMR-induced gaps initiated at alkylation induced O6-mG:C sites and BER-induced nicks at nearby N-alkylation adducts in the opposite strand. The accidental encounter between these two repair events is causal in the formation of DSBs and the resulting cellular response, documenting a third model to account for O6-mG induced cell death in non-replicating cells. This graphical review highlights the details of this Repair Accident model, as compared to current models, and we discuss potential strategies to improve clinical use of alkylating agents such as temozolomide, that can be inferred from the Repair Accident model.
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Affiliation(s)
- Shingo Fujii
- Marseille Medical Genetics, UMR1251 Marseille, France
| | - Robert W Sobol
- Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA; Dept of Pharmacology, College of Medicine, University of South Alabama, Mobile, AL, USA.
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5
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Crocker K, London J, Medina A, Fishel R, Bundschuh R. Evolutionary advantage of a dissociative search mechanism in DNA mismatch repair. Phys Rev E 2021; 103:052404. [PMID: 34134264 PMCID: PMC8514111 DOI: 10.1103/physreve.103.052404] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2020] [Accepted: 04/08/2021] [Indexed: 01/10/2023]
Abstract
Protein complexes involved in DNA mismatch repair diffuse along dsDNA as sliding clamps in order to locate a hemimethylated incision site. They have been observed to use a dissociative mechanism, in which two proteins, while continuously remaining attached to the DNA, sometimes associate into a single complex sliding on the DNA and sometimes dissociate into two independently sliding proteins. Here, we study the probability that these complexes locate a given target site via a semi-analytic, Monte Carlo calculation that tracks the association and dissociation of the sliding complexes. We compare such probabilities to those obtained using a nondissociative diffusive scan in the space of physically realistic diffusion constants, hemimethylated site distances, and total search times to determine the regions in which dissociative searching is more or less efficient than nondissociative searching. We conclude that the dissociative search mechanism is advantageous in the majority of the physically realistic parameter space, suggesting that the dissociative search mechanism confers an evolutionary advantage.
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Affiliation(s)
- Kyle Crocker
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - James London
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Andrés Medina
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Richard Fishel
- Department of Cancer Biology and Genetics, The Ohio State University, Columbus, Ohio 43210, USA
| | - Ralf Bundschuh
- Department of Physics, Department of Chemistry and Biochemistry, Division of Hematology, Department of Internal Medicine, The Ohio State University, Columbus, Ohio 43210, USA
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Köberle B, Schoch S. Platinum Complexes in Colorectal Cancer and Other Solid Tumors. Cancers (Basel) 2021; 13:cancers13092073. [PMID: 33922989 PMCID: PMC8123298 DOI: 10.3390/cancers13092073] [Citation(s) in RCA: 31] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 04/22/2021] [Accepted: 04/23/2021] [Indexed: 12/25/2022] Open
Abstract
Simple Summary Cisplatin is successfully used for the treatment of various solid cancers. Unfortunately, it shows no activity in colorectal cancer. The resistance phenotype of colorectal cancer cells is mainly caused by alterations in p53-controlled DNA damage signaling and/or defects in the cellular mismatch repair pathway. Improvement of platinum-based chemotherapy in cisplatin-unresponsive cancers, such as colorectal cancer, might be achieved by newly designed cisplatin analogues, which retain activity in unresponsive tumor cells. Moreover, a combination of cisplatin with biochemical modulators of DNA damage signaling might sensitize cisplatin-resistant tumor cells to the drug, thus providing another strategy to improve cancer therapy. Abstract Cisplatin is one of the most commonly used drugs for the treatment of various solid neoplasms, including testicular, lung, ovarian, head and neck, and bladder cancers. Unfortunately, the therapeutic efficacy of cisplatin against colorectal cancer is poor. Various mechanisms appear to contribute to cisplatin resistance in cancer cells, including reduced drug accumulation, enhanced drug detoxification, modulation of DNA repair mechanisms, and finally alterations in cisplatin DNA damage signaling preventing apoptosis in cancer cells. Regarding colorectal cancer, defects in mismatch repair and altered p53-mediated DNA damage signaling are the main factors controlling the resistance phenotype. In particular, p53 inactivation appears to be associated with chemoresistance and poor prognosis. To overcome resistance in cancers, several strategies can be envisaged. Improved cisplatin analogues, which retain activity in resistant cancer, might be applied. Targeting p53-mediated DNA damage signaling provides another therapeutic strategy to circumvent cisplatin resistance. This review provides an overview on the DNA repair pathways involved in the processing of cisplatin damage and will describe signal transduction from cisplatin DNA lesions, with special attention given to colorectal cancer cells. Furthermore, examples for improved platinum compounds and biochemical modulators of cisplatin DNA damage signaling will be presented in the context of colon cancer therapy.
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Affiliation(s)
- Beate Köberle
- Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology, Adenauerring 20a, 76131 Karlsruhe, Germany
| | - Sarah Schoch
- Department of Laboratory Medicine, Lund University, Scheelevägen 2, 223 81 Lund, Sweden
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MacLeod G, Bozek DA, Rajakulendran N, Monteiro V, Ahmadi M, Steinhart Z, Kushida MM, Yu H, Coutinho FJ, Cavalli FMG, Restall I, Hao X, Hart T, Luchman HA, Weiss S, Dirks PB, Angers S. Genome-Wide CRISPR-Cas9 Screens Expose Genetic Vulnerabilities and Mechanisms of Temozolomide Sensitivity in Glioblastoma Stem Cells. Cell Rep 2020; 27:971-986.e9. [PMID: 30995489 DOI: 10.1016/j.celrep.2019.03.047] [Citation(s) in RCA: 127] [Impact Index Per Article: 31.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 12/19/2018] [Accepted: 03/13/2019] [Indexed: 01/14/2023] Open
Abstract
Glioblastoma therapies have remained elusive due to limitations in understanding mechanisms of growth and survival of the tumorigenic population. Using CRISPR-Cas9 approaches in patient-derived GBM stem cells (GSCs) to interrogate function of the coding genome, we identify actionable pathways responsible for growth, which reveal the gene-essential circuitry of GBM stemness and proliferation. In particular, we characterize members of the SOX transcription factor family, SOCS3, USP8, and DOT1L, and protein ufmylation as important for GSC growth. Additionally, we reveal mechanisms of temozolomide resistance that could lead to combination strategies. By reaching beyond static genome analysis of bulk tumors, with a genome-wide functional approach, we reveal genetic dependencies within a broad range of biological processes to provide increased understanding of GBM growth and treatment resistance.
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Affiliation(s)
- Graham MacLeod
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Danielle A Bozek
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | | | - Vernon Monteiro
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Moloud Ahmadi
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Zachary Steinhart
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Michelle M Kushida
- Developmental and Stem Cell Biology Program and Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON, Canada
| | - Helen Yu
- Developmental and Stem Cell Biology Program and Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON, Canada
| | - Fiona J Coutinho
- Developmental and Stem Cell Biology Program and Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON, Canada
| | - Florence M G Cavalli
- Developmental and Stem Cell Biology Program and Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON, Canada
| | - Ian Restall
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Xiaoguang Hao
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Traver Hart
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA
| | - H Artee Luchman
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Samuel Weiss
- Hotchkiss Brain Institute, Department of Cell Biology and Anatomy, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Peter B Dirks
- Developmental and Stem Cell Biology Program and Arthur and Sonia Labatt Brain Tumour Research Centre, The Hospital for Sick Children, Toronto, ON, Canada; Department of Molecular Genetics, Department of Laboratory Medicine and Pathobiology, Division of Neurosurgery, Department of Surgery, Faculty of Medicine, University of Toronto, Toronto, ON, Canada; Division of Neurosurgery, The Hospital for Sick Children, Toronto, ON, Canada.
| | - Stephane Angers
- Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada; Department of Biochemistry, Faculty of Medicine, University of Toronto, Toronto, ON, Canada.
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8
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Higuchi F, Nagashima H, Ning J, Koerner MVA, Wakimoto H, Cahill DP. Restoration of Temozolomide Sensitivity by PARP Inhibitors in Mismatch Repair Deficient Glioblastoma is Independent of Base Excision Repair. Clin Cancer Res 2020; 26:1690-1699. [PMID: 31900275 DOI: 10.1158/1078-0432.ccr-19-2000] [Citation(s) in RCA: 78] [Impact Index Per Article: 19.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2019] [Revised: 11/09/2019] [Accepted: 12/18/2019] [Indexed: 01/23/2023]
Abstract
PURPOSE Emergence of mismatch repair (MMR) deficiency is a frequent mechanism of acquired resistance to the alkylating chemotherapeutic temozolomide (TMZ) in gliomas. Poly(ADP-ribose) polymerase inhibitors (PARPi) have been shown to potentiate TMZ cytotoxicity in several cancer types, including gliomas. We tested whether PARP inhibition could re-sensitize MSH6-null MMR-deficient gliomas to TMZ, and assessed the role of the base excision repair (BER) DNA damage repair pathway in PARPi-mediated effects. EXPERIMENTAL DESIGN Isogenic pairs of MSH6 wild-type and MSH6-inactivated human glioblastoma (GBM) cells (including both IDH1/2 wild-type and IDH1 mutant), as well as MSH6-null cells derived from a patient with recurrent GBM were treated with TMZ, the PARPi veliparib or olaparib, and combination thereof. Efficacy of PARPi combined with TMZ was assessed in vivo. We used genetic and pharmacological approaches to dissect the contribution of BER. RESULTS While having no detectable effect in MSH6 wild-type GBMs, PARPi selectively restored TMZ sensitivity in MSH6-deficient GBM cells. This genotype-specific restoration of activity translated in vivo, where combination treatment of veliparib and TMZ showed potent suppression of tumor growth of MSH6-inactivated orthotopic xenografts, compared with TMZ monotherapy. Unlike PARPi, genetic and pharmacological blockage of BER pathway did not re-sensitize MSH6-inactivated GBM cells to TMZ. Similarly, CRISPR PARP1 knockout did not re-sensitize MSH6-inactivated GBM cells to TMZ. CONCLUSIONS PARPi restoration of TMZ chemosensitivity in MSH6-inactivated glioma represents a promising strategy to overcome acquired chemoresistance caused by MMR deficiency. Mechanistically, this PARPi-mediated synthetic phenotype was independent of BER blockage and was not recapitulated by loss of PARP1.
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Affiliation(s)
- Fumi Higuchi
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.,Department of Neurosurgery, Dokkyo Medical University, Mibu, Tochigi, Japan
| | - Hiroaki Nagashima
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Jianfang Ning
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.,Department of Neurosurgery, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Mara V A Koerner
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts
| | - Hiroaki Wakimoto
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
| | - Daniel P Cahill
- Department of Neurosurgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
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9
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Colic M, Wang G, Zimmermann M, Mascall K, McLaughlin M, Bertolet L, Lenoir WF, Moffat J, Angers S, Durocher D, Hart T. Identifying chemogenetic interactions from CRISPR screens with drugZ. Genome Med 2019; 11:52. [PMID: 31439014 PMCID: PMC6706933 DOI: 10.1186/s13073-019-0665-3] [Citation(s) in RCA: 105] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2019] [Accepted: 08/12/2019] [Indexed: 12/18/2022] Open
Abstract
BACKGROUND Chemogenetic profiling enables the identification of gene mutations that enhance or suppress the activity of chemical compounds. This knowledge provides insights into drug mechanism of action, genetic vulnerabilities, and resistance mechanisms, all of which may help stratify patient populations and improve drug efficacy. CRISPR-based screening enables sensitive detection of drug-gene interactions directly in human cells, but until recently has primarily been used to screen only for resistance mechanisms. RESULTS We present drugZ, an algorithm for identifying both synergistic and suppressor chemogenetic interactions from CRISPR screens. DrugZ identifies synthetic lethal interactions between PARP inhibitors and both known and novel members of the DNA damage repair pathway, confirms KEAP1 loss as a resistance factor for ERK inhibitors in oncogenic KRAS backgrounds, and defines the genetic context for temozolomide activity. CONCLUSIONS DrugZ is an open-source Python software for the analysis of genome-scale drug modifier screens. The software accurately identifies genetic perturbations that enhance or suppress drug activity. Interestingly, analysis of new and previously published data reveals tumor suppressor genes are drug-agnostic resistance genes in drug modifier screens. The software is available at github.com/hart-lab/drugz .
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Affiliation(s)
- Medina Colic
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- UTHealth Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Gang Wang
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Michal Zimmermann
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
| | - Keith Mascall
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
| | - Megan McLaughlin
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Lori Bertolet
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - W Frank Lenoir
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
- UTHealth Graduate School of Biomedical Sciences, The University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Jason Moffat
- Donnelly Centre, University of Toronto, Toronto, ON, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Stephane Angers
- Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, ON, Canada
- Department of Biochemistry, University of Toronto, Toronto, ON, Canada
| | - Daniel Durocher
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, 600 University Avenue, Toronto, ON, M5G 1X5, Canada
- Department of Molecular Genetics, University of Toronto, Toronto, ON, M5S 3E1, Canada
| | - Traver Hart
- Department of Bioinformatics and Computational Biology, The University of Texas MD Anderson Cancer Center, Houston, TX, USA.
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10
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Inactivation of XPF Sensitizes Cancer Cells to Gemcitabine. J Nucleic Acids 2019; 2019:6357609. [PMID: 30941207 PMCID: PMC6421022 DOI: 10.1155/2019/6357609] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2018] [Revised: 12/26/2018] [Accepted: 02/03/2019] [Indexed: 12/22/2022] Open
Abstract
Gemcitabine (2′, 2′-difluorodeoxycytidine; dFdC) is a deoxycytidine analog and is used primarily against pancreatic cancer. The cytotoxicity of gemcitabine is due to the inhibition of DNA replication. However, a mechanism of removal of the incorporated dFdC is largely unknown. In this report, we discovered that nucleotide excision repair protein XPF-ERCC1 participates in the repair of gemcitabine-induced DNA damage and inactivation of XPF sensitizes cells to gemcitabine. Further analysis identified that XPF-ERCC1 functions together with apurinic/apyrimidinic endonuclease (APE) in the repair of gemcitabine-induced DNA damage. Our results demonstrate the importance of the evaluation of DNA repair activities in gemcitabine treatment.
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11
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Signal transduction pathways and resistance to targeted therapies in glioma. Semin Cancer Biol 2019; 58:118-129. [PMID: 30685341 DOI: 10.1016/j.semcancer.2019.01.004] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2018] [Revised: 01/18/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Although surgical techniques and adjuvant therapies have undergone progressive development for decades, the therapeutic outcomes for treating glioblastoma (GBM) remain poor. The main reasons for the poor prognosis of gliomas are that limited tumor tissue that can be resected (to preserve brain functions) and that residual tumors are often resistant to irradiation and chemotherapy. Therefore, overcoming the resistance of residual tumors against adjuvant therapy is urgently needed for glioma treatment. Recent large cohort studies of genetic alterations in GBM demonstrated that both genetic information and intracellular molecular signaling are networked in gliomas and that such information may help clarify which molecules or signals serve essential roles in resistance against radiation or chemotherapy, highlighting them as potential novel therapeutic targets against refractory gliomas. In this review, we summarize the current understanding of molecular networks that govern glioma biology, mainly based on cohort studies or recent evidence, with a focus on how intracellular signaling molecules in gliomas associate with each other and regulate refractoriness against current therapy.
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Kawall K. New Possibilities on the Horizon: Genome Editing Makes the Whole Genome Accessible for Changes. FRONTIERS IN PLANT SCIENCE 2019; 10:525. [PMID: 31068963 PMCID: PMC6491833 DOI: 10.3389/fpls.2019.00525] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/04/2019] [Indexed: 05/04/2023]
Abstract
The emergence of new genome editing techniques, such as the site-directed nucleases, clustered regulatory interspaced short palindromic repeats (CRISPRs)/Cas9, transcription activator-like effector nucleases (TALENs), or zinc finger nucleases (ZFNs), has greatly increased the feasibility of introducing any desired changes into the genome of a target organism. The ability to target a Cas nuclease to DNA sequences with a single-guide RNA (sgRNA) has provided a dynamic tool for genome editing and is naturally derived from an adaptive immune system in bacteria and archaea. CRISPR/Cas systems are being rapidly improved and refined, thereby opening up even more possibilities. Classical plant breeding is based on genetic variations that occur naturally and is used to select plants with improved traits. Induced mutagenesis is used to enhance mutational frequency and accelerate this process. Plants have evolved cellular processes, including certain repair mechanisms that ensure DNA integrity and the maintenance of distinct DNA loci. The focus of this review is on the characterization of new potentials in plant breeding through the use of CRISPR/Cas systems that eliminate natural limitations in order to induce thus far unachievable genomic changes.
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13
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Hombach-Klonisch S, Mehrpour M, Shojaei S, Harlos C, Pitz M, Hamai A, Siemianowicz K, Likus W, Wiechec E, Toyota BD, Hoshyar R, Seyfoori A, Sepehri Z, Ande SR, Khadem F, Akbari M, Gorman AM, Samali A, Klonisch T, Ghavami S. Glioblastoma and chemoresistance to alkylating agents: Involvement of apoptosis, autophagy, and unfolded protein response. Pharmacol Ther 2018; 184:13-41. [DOI: 10.1016/j.pharmthera.2017.10.017] [Citation(s) in RCA: 192] [Impact Index Per Article: 32.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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14
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Xu K, Zhang Z, Pei H, Wang H, Li L, Xia Q. FoxO3a induces temozolomide resistance in glioblastoma cells via the regulation of β-catenin nuclear accumulation. Oncol Rep 2017; 37:2391-2397. [PMID: 28260024 DOI: 10.3892/or.2017.5459] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Accepted: 01/30/2017] [Indexed: 11/05/2022] Open
Abstract
Glioblastoma multiforme (GBM), the most common malignant brain tumor, is currently treated with temozolomide (TMZ), but GBM often exhibits resistance to TMZ. Although several mechanisms underlying GBM resistance to TMZ have been identified, these mechanisms are yet to fully explain how GBM gains resistance to TMZ. Our previous work has shown that FoxO3a, a member of the FoxO subfamily of transcription factors, promotes glioma cell proliferation and invasion. In this study, we sought to determine whether FoxO3a participates in TMZ resistance in GBM cells. Parental cell lines (also designated as sensitive cell lines) U87-MG and U251-MG, as well as the corresponding resistant cell lines U87-TR and U251-TR (generated by repeated TMZ treatments), were subjected to western blot analysis. Our results showed that the resistant cells (both U87-TRand U251-TR) exhibited higher levels of FoxO3a and β-catenin relative to their corresponding sensitive counterparts. Depletion of FoxO3a in the resistant cells enhanced the cytotoxic effect of TMZ. Further investigation showed that FoxO3a depletion did not affect the total protein level of β-catenin, but otherwise markedly reduced the nuclear β-catenin level. Taken together, these findings strongly support that FoxO3a renders GBM cells resistant to TMZ treatment, at least in part, through the regulation of β-catenin nuclear accumulation.
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Affiliation(s)
- Ke Xu
- Department of Immunology, School of Tropical and Laboratory Medicine, Hainan Medical University, Haikou, Hainan 571101, P.R. China
| | - Zhenhao Zhang
- Medical Technology Institute of Xuzhou Medical University, Xuzhou, Jiangsu 221004, P.R. China
| | - Hua Pei
- Department of Immunology, School of Tropical and Laboratory Medicine, Hainan Medical University, Haikou, Hainan 571101, P.R. China
| | - Huamin Wang
- Department of Immunology, School of Tropical and Laboratory Medicine, Hainan Medical University, Haikou, Hainan 571101, P.R. China
| | - Liang Li
- Department of Immunology, School of Tropical and Laboratory Medicine, Hainan Medical University, Haikou, Hainan 571101, P.R. China
| | - Qianfeng Xia
- Key Laboratory of Tropical Biomedicine, and Faculty of Tropical Medicine and Laboratory Medicine, Hainan Medical University, Haikou, Hainan 571101, P.R. China
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15
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Ydy LRA, do Espírito Santo GF, de Menezes I, Martins MS, Ignotti E, Damazo AS. Study of the Annexin A1 and Its Associations with Carcinoembryonic Antigen and Mismatch Repair Proteins in Colorectal Cancer. J Gastrointest Cancer 2016; 47:61-8. [PMID: 26687139 DOI: 10.1007/s12029-015-9791-3] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
PURPOSE Annexin-A1 (ANXA1) has been implicated in various tumor types, but few studies have investigated its involvement in colorectal cancer. The study aimed to analyze ANXA1 expression in the normal margin and colorectal tumor tissues of 104 patients who underwent surgery for colorectal cancer and to associate the ANXA1 expression with predictive clinicopathological variables. METHODS Hematoxylin-eosin and immunohistochemical staining were used for the analysis. RESULTS ANXA1 expression was higher in colorectal cancer than in normal margin tissue (p = 0.0001). However, no differences were observed when we analyzed the ANXA1 expression in colon and rectal tumors (p = 0.830). Also, this protein positivity was associated with increased carcinoembryonic antigen levels (p = 0.004). Our data in the DNA-mismatch repair proteins expression was in accordance to the literature. And their positivity was not associated with ANXA1 presence in colorectal cancer. CONCLUSION The high incidence of ANXA1 positive expression in colorectal cancer and its association with carcinoembryonic antigen levels might indicate the importance of this protein in the colorectal cancer biology.
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Affiliation(s)
- Lenuce Ribeiro Aziz Ydy
- Post-Graduate Program in Health Sciences, Faculty of Medicine (FM), Federal University of Mato Grosso (UFMT), 78060-900, Cuiabá, MT, Brazil.
| | | | - Ivana de Menezes
- Post-Graduate Program in Health Sciences, Faculty of Medicine (FM), Federal University of Mato Grosso (UFMT), 78060-900, Cuiabá, MT, Brazil.,Laboratory of Pathology, Faculty of Medicine, University Hospital Júlio Muller, UFMT, Cuiabá, MT, Brazil
| | | | - Eliane Ignotti
- Post-Graduate Program in Health Sciences, Faculty of Medicine (FM), Federal University of Mato Grosso (UFMT), 78060-900, Cuiabá, MT, Brazil.,Department of Nursing, State University of Mato Grosso (UNEMAT), Cáceres, MT, Brazil
| | - Amílcar Sabino Damazo
- Post-Graduate Program in Health Sciences, Faculty of Medicine (FM), Federal University of Mato Grosso (UFMT), 78060-900, Cuiabá, MT, Brazil. .,Department of Basic Health Sciences, Faculty of Medicine (FM), Federal University of Mato Grosso (UFMT), 78060-900, Cuiabá, MT, Brazil.
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16
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Liu J, Hanne J, Britton BM, Bennett J, Kim D, Lee JB, Fishel R. Cascading MutS and MutL sliding clamps control DNA diffusion to activate mismatch repair. Nature 2016; 539:583-587. [PMID: 27851738 PMCID: PMC5845140 DOI: 10.1038/nature20562] [Citation(s) in RCA: 82] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2016] [Accepted: 10/21/2016] [Indexed: 01/25/2023]
Abstract
Mismatched nucleotides arise from polymerase misincorporation errors, recombination between heteroallelic parents and chemical or physical DNA damage. Highly conserved MutS (MSH) and MutL (MLH/PMS) homologues initiate mismatch repair and, in higher eukaryotes, act as DNA damage sensors that can trigger apoptosis. Defects in human mismatch repair genes cause Lynch syndrome or hereditary non-polyposis colorectal cancer and 10-40% of related sporadic tumours. However, the collaborative mechanics of MSH and MLH/PMS proteins have not been resolved in any organism. We visualized Escherichia coli (Ec) ensemble mismatch repair and confirmed that EcMutS mismatch recognition results in the formation of stable ATP-bound sliding clamps that randomly diffuse along the DNA with intermittent backbone contact. The EcMutS sliding clamps act as a platform to recruit EcMutL onto the mismatched DNA, forming an EcMutS-EcMutL search complex that then closely follows the DNA backbone. ATP binding by EcMutL establishes a second long-lived DNA clamp that oscillates between the principal EcMutS-EcMutL search complex and unrestricted EcMutS and EcMutL sliding clamps. The EcMutH endonuclease that targets mismatch repair excision only binds clamped EcMutL, increasing its DNA association kinetics by more than 1,000-fold. The assembly of an EcMutS-EcMutL-EcMutH search complex illustrates how sequential stable sliding clamps can modulate one-dimensional diffusion mechanics along the DNA to direct mismatch repair.
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Affiliation(s)
- Jiaquan Liu
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Jeungphill Hanne
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Brooke M Britton
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Jared Bennett
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA
| | - Daehyung Kim
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Korea
| | - Jong-Bong Lee
- Department of Physics, Pohang University of Science and Technology (POSTECH), Pohang, Kyungbuk 790-784, Korea
- School of Interdisciplinary Bioscience and Bioengineering, POSTECH, Pohang, Kyungbuk, 790-784, Korea
| | - Richard Fishel
- Department of Cancer Biology and Genetics, The Ohio State University Wexner Medical Center, Columbus, Ohio 43210, USA
- Department of Physics, The Ohio State University, Columbus, Ohio 43210, USA
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17
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Heo JC, Jung TH, Lee S, Kim HY, Choi G, Jung M, Jung D, Lee HK, Lee JO, Park JH, Hwang D, Seol HJ, Cho H. Effect of bexarotene on differentiation of glioblastoma multiforme compared with ATRA. Clin Exp Metastasis 2016; 33:417-29. [DOI: 10.1007/s10585-016-9786-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2015] [Accepted: 02/25/2016] [Indexed: 12/27/2022]
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18
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Sawant A, Kothandapani A, Zhitkovich A, Sobol RW, Patrick SM. Role of mismatch repair proteins in the processing of cisplatin interstrand cross-links. DNA Repair (Amst) 2015; 35:126-36. [PMID: 26519826 DOI: 10.1016/j.dnarep.2015.10.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 10/09/2015] [Accepted: 10/10/2015] [Indexed: 12/13/2022]
Abstract
Mismatch repair (MMR) deficiency gives rise to cisplatin resistance and can lead to poor prognosis in cancers. Various models have been proposed to explain this low level of resistance caused due to loss of MMR proteins. We have shown that MMR proteins are required to maintain cisplatin interstrand cross-links (ICLs) on the DNA leading to increased cellular sensitivity. In our previous studies, we have shown that BER processing of the cisplatin ICLs is mutagenic. Polymerase β (Polβ) can generate mismatches which leads to the activation and the recruitment of mismatch repair proteins. In this paper, we distinguished between the requirement of different downstream MMR proteins for maintaining cisplatin sensitivity. We show that the MutSα (MSH2-MSH6) heterocomplex is required to maintain cisplatin sensitivity, whereas the Mutsβ complex has no effect. These results can be correlated with the increased repair of cisplatin ICLs and ICL induced DNA double strand breaks (DSBs) in the resistant cells. Moreover, we show that MLH1 proficient cells displayed a cisplatin sensitive phenotype when compared with the MLH1 deficient cells and the ATPase activity of MLH1 is essential to mediate this effect. Based on these results, we propose that MutSα as well as the downstream MMR pathway proteins are essential to maintain a cisplatin sensitive phenotype as a consequence of processing Polβ induced mismatches at sites flanking cisplatin ICLs.
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Affiliation(s)
- Akshada Sawant
- Department of Biochemistry and Cancer Biology, University of Toledo-Health Science Campus, Toledo, OH 43614, USA
| | - Anbarasi Kothandapani
- Department of Biochemistry and Cancer Biology, University of Toledo-Health Science Campus, Toledo, OH 43614, USA
| | - Anatoly Zhitkovich
- Department of Pathology and Laboratory Medicine, Alpert Medical School, Brown University, Providence, RI 02912, USA
| | - Robert W Sobol
- Department of Pharmacology & Chemical Biology, University of Pittsburgh School of Medicine, Pittsburgh, PA 15213, USA; University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, PA 15213, USA; Department of Human Genetics, University of Pittsburgh Graduate School of Public Health, Pittsburgh, PA 15213, USA; Department of Oncologic Sciences, Molecular & Metabolic Oncology Program, University of South Alabama Mitchell Cancer Institute, 1660 Springhill Avenue, Mobile, AL 36604, USA
| | - Steve M Patrick
- Department of Oncology, Karmanos Cancer Institute, Wayne State University, Detroit, MI 48201, USA.
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19
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Shinsato Y, Furukawa T, Yunoue S, Yonezawa H, Minami K, Nishizawa Y, Ikeda R, Kawahara K, Yamamoto M, Hirano H, Tokimura H, Arita K. Reduction of MLH1 and PMS2 confers temozolomide resistance and is associated with recurrence of glioblastoma. Oncotarget 2014; 4:2261-70. [PMID: 24259277 PMCID: PMC3926825 DOI: 10.18632/oncotarget.1302] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Although there is a relationship between DNA repair deficiency and temozolomide (TMZ) resistance in glioblastoma (GBM), it remains unclear which molecule is associated with GBM recurrence. We isolated three TMZ-resistant human GBM cell lines and examined the expression of O6-methylguanine-DNA methyltransferase (MGMT) and mismatch repair (MMR) components. We used immunohistochemical analysis to compare MutL homolog 1 (MLH1), postmeiotic segregation increased 2 (PMS2) and MGMT expression in primary and recurrent GBM specimens obtained from GBM patients during TMZ treatment. We found a reduction in MLH1 expression and a subsequent reduction in PMS2 protein levels in TMZ-resistant cells. Furthermore, MLH1 or PMS2 knockdown confered TMZ resistance. In recurrent GBM tumours, the expression of MLH1 and PMS2 was reduced when compared to primary tumours.
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Affiliation(s)
- Yoshinari Shinsato
- Department of Neurosurgery, Graduate School of Medical and Dental Sciences Kagoshima University, Kagoshima, Japan
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20
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De Zio D, Cianfanelli V, Cecconi F. New insights into the link between DNA damage and apoptosis. Antioxid Redox Signal 2013; 19:559-71. [PMID: 23025416 PMCID: PMC3717195 DOI: 10.1089/ars.2012.4938] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
SIGNIFICANCE When lesions are unrepaired or there are defects in the DNA repair system, DNA damage is often correlated to apoptosis. However, different kinds of lesions and different degrees of lesion severity can trigger numerous signaling responses. RECENT ADVANCES DNA repair proteins involved in specific DNA repair pathways can modulate the function or activity of some apoptotic factors, further emphasizing the crosstalk between DNA damage and cell death. CRITICAL ISSUES Here, we discuss the signaling networks that link DNA damage to apoptosis, and we focus on post-translational modifications, leading to crucial changes in protein behavior, following various kinds of DNA damage. Moreover, we analyze the existence of apoptosis-related functions of typical repair proteins, leading to diverse, often-overlapping, DNA damage responses. FUTURE DIRECTIONS The better understanding of the regulation and the functionality of key DNA repair proteins, also involved in apoptosis regulation, has the potential of modulating the cell outcomes on DNA damage, particularly in the context of cancer treatment.
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Affiliation(s)
- Daniela De Zio
- Dulbecco Telethon Institute at the Department of Biology, University of Rome Tor Vergata, Rome, Italy.
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21
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Abstract
Normal cell function requires strict control over the repair of DNA damage, which prevents excessive mutagenesis. An enhanced accumulation of mutations results in the multistep process generally known as carcinogenesis. Defects in repair pathways fuel such mutagenesis by allowing reiterative cycles of mutation, selection, and clonal expansion that drive cancer progression. The repair of mismatches is an important mechanism in the prevention of such genetic instability. In addition, proteins of this pathway have the unique ability to function in DNA damage response by inducing apoptosis when irreparable damage is encountered. Though originally identified primarily in association with a predisposition to hereditary colon cancer, mismatch repair defects have been identified in many other cancer types, including prostate cancer. From the first discovery of microsatellite instability in prostate cancer cell lines and tumor samples, variations in protein levels and a possible association with recurrence and aggression of disease have been described. Current results suggest that the involvement of mismatch repair proteins in prostate cancer may differ from that found in colorectal cancer, in the type of proteins and protein defects involved and the type of causative mutations. Additional work is clearly needed to investigate this involvement and the possibility that such defects may affect treatment response and androgen independence.
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Affiliation(s)
- John Jarzen
- Department of Biology, College of Science and Technology, Georgia Southern University, Statesboro, Georgia, USA
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22
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Sedletska Y, Culard F, Midoux P, Malinge JM. Interaction studies of muts and mutl with DNA containing the major cisplatin lesion and its mismatched counterpart under equilibrium and nonequilibrium conditions. Biopolymers 2013; 99:636-47. [DOI: 10.1002/bip.22232] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2012] [Revised: 02/04/2013] [Accepted: 03/05/2013] [Indexed: 11/12/2022]
Affiliation(s)
| | - Françoise Culard
- Centre de Biophysique Moléculaire; CNRS UPR 4301; affiliated to the University of Orléans and INSERM; rue Charles Sadron, 45071 Orléans Cedex 02; France
| | - Patrick Midoux
- Centre de Biophysique Moléculaire; CNRS UPR 4301; affiliated to the University of Orléans and INSERM; rue Charles Sadron, 45071 Orléans Cedex 02; France
| | - Jean-Marc Malinge
- Centre de Biophysique Moléculaire; CNRS UPR 4301; affiliated to the University of Orléans and INSERM; rue Charles Sadron, 45071 Orléans Cedex 02; France
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23
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Affiliation(s)
- Himisha Beltran
- Weill Cornell Medical College, Division of Hematology and Medical Oncology, 525 East 68th St, New York, NY 10021, USA.
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24
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Chiang MF, Chou PY, Wang WJ, Sze CI, Chang NS. Tumor Suppressor WWOX and p53 Alterations and Drug Resistance in Glioblastomas. Front Oncol 2013; 3:43. [PMID: 23459853 PMCID: PMC3586680 DOI: 10.3389/fonc.2013.00043] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Accepted: 02/17/2013] [Indexed: 12/27/2022] Open
Abstract
Tumor suppressor p53 are frequently mutated in glioblastomas (GBMs) and appears to contribute, in part, to resistance to temozolomide (TMZ) and therapeutic drugs. WW domain-containing oxidoreductase WWOX (FOR or WOX1) is a proapoptotic protein and is considered as a tumor suppressor. Loss of WWOX gene expression is frequently seen in malignant cancer cells due to promoter hypermethylation, genetic alterations, and translational blockade. Intriguingly, ectopic expression of wild type WWOX preferentially induces apoptosis in human glioblastoma cells harboring mutant p53. WWOX is known to physically bind and stabilize wild type p53. Here, we provide an overview for the updated knowledge in p53 and WWOX, and postulate potential scenarios that wild type and mutant p53, or isoforms, modulate the apoptotic function of WWOX. We propose that triggering WWOX activation by therapeutic drugs under p53 functional deficiency is needed to overcome TMZ resistance and induce GBM cell death.
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Affiliation(s)
- Ming-Fu Chiang
- Department of Neurosurgery, Mackay Memorial Hospital Taipei, Taiwan ; Graduate Institute of Injury Prevention and Control, Taipei Medical University Taipei, Taiwan
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25
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Hirohata T, Asano K, Ogawa Y, Takano S, Amano K, Isozaki O, Iwai Y, Sakata K, Fukuhara N, Nishioka H, Yamada S, Fujio S, Arita K, Takano K, Tominaga A, Hizuka N, Ikeda H, Osamura RY, Tahara S, Ishii Y, Kawamata T, Shimatsu A, Teramoto A, Matsuno A. DNA mismatch repair protein (MSH6) correlated with the responses of atypical pituitary adenomas and pituitary carcinomas to temozolomide: the national cooperative study by the Japan Society for Hypothalamic and Pituitary Tumors. J Clin Endocrinol Metab 2013; 98:1130-6. [PMID: 23365123 DOI: 10.1210/jc.2012-2924] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Temozolomide (TMZ) is an alkylating agent and was a first-line chemotherapeutic agent for malignant gliomas. Recently, TMZ has been documented to be effective against atypical pituitary adenomas (APAs) and pituitary carcinomas (PCs). OBJECTIVE The clinical and pathological characteristics of APAs and PCs treated with TMZ in Japan were surveyed and analyzed retrospectively. DESIGN Members of the Japan Society of Hypothalamic and Pituitary Tumors were surveyed regarding the clinical characteristics of APAs and PCs treated with TMZ. Stored tumor samples were gathered from the responders and were assessed by the immunohistochemistry of Ki-67, O(6)-methyl-guanine-DNA methyltransferase, p53, MSH6, and anterior pituitary hormones. Responses to TMZ treatment were defined as complete response (CR), partial response (PR), progressive disease (PD), and stable disease (SD) according to RECIST (Response Evaluation Criteria in Solid Tumors) version 2.0. SUBJECTS Three samples from 3 subjects with APA and 11 samples from 10 subjects with PC were available. RESULTS The 13 subjects had APAs and PCs consisting of 5 prolactin-producing tumors, 5 ACTH-producing tumors, and 3 null cell adenomas. The clinical response to TMZ treatment was as follows: 4 cases of CR and PR (31%), 2 cases of SD (15%), 6 cases of recurrence after CR and PR (46%), and 1 case of PD (8%). However, considerable subjects had recurrent disease after a response to TMZ. The immunohistochemical findings of Ki-67, O(6)-methyl-guanine-DNA methyltransferase, and p53 did not show any significant correlation with the efficacy of TMZ. However, the immunopositivity of MSH6 was positively correlated with TMZ response (P = .015, Fisher's exact test). CONCLUSIONS This study showed that preserving MSH6 function was contributory to the effectiveness of TMZ in malignant pituitary neoplasms. It is necessary to survey more cases and evaluate multifactor analyses.
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Affiliation(s)
- Toshio Hirohata
- Department of Neurosurgery, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan.
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Yoshimoto K, Mizoguchi M, Hata N, Murata H, Hatae R, Amano T, Nakamizo A, Sasaki T. Complex DNA repair pathways as possible therapeutic targets to overcome temozolomide resistance in glioblastoma. Front Oncol 2012; 2:186. [PMID: 23227453 PMCID: PMC3514620 DOI: 10.3389/fonc.2012.00186] [Citation(s) in RCA: 80] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2012] [Accepted: 11/16/2012] [Indexed: 12/31/2022] Open
Abstract
Many conventional chemotherapeutic drugs exert their cytotoxic function by inducing DNA damage in the tumor cell. Therefore, a cell-inherent DNA repair pathway, which reverses the DNA-damaging effect of the cytotoxic drugs, can mediate therapeutic resistance to chemotherapy. The monofunctional DNA-alkylating agent temozolomide (TMZ) is a commonly used chemotherapeutic drug and the gold standard treatment for glioblastoma (GBM). Although the activity of DNA repair protein O6-methylguanine-DNA methyltransferase (MGMT) has been described as the main modulator to determine the sensitivity of GBM to TMZ, a subset of GBM does not respond despite MGMT inactivation, suggesting that another DNA repair mechanism may also modulate the tolerance to TMZ. Considerable interest has focused on MGMT, mismatch repair (MMR), and the base excision repair (BER) pathway in the mechanism of mediating TMZ resistance, but emerging roles for the DNA strand-break repair pathway have been demonstrated. In the first part of this review article, we briefly review the significant role of MGMT, MMR, and the BER pathway in the tolerance to TMZ; in the last part, we review the recent publications that demonstrate possible roles of DNA strand-break repair pathways, such as single-strand break repair and double-strand break repair, as well as the Fanconi anemia pathway in the repair process after alkylating agent-based therapy. It is possible that all of these repair pathways have a potential to modulate the sensitivity to TMZ and aid in overcoming the therapeutic resistance in the clinic.
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Affiliation(s)
- Koji Yoshimoto
- Department of Neurosurgery, Graduate School of Medical Sciences, Kyushu University Fukuoka, Japan
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Exonuclease 1 (Exo1) is required for activating response to S(N)1 DNA methylating agents. DNA Repair (Amst) 2012; 11:951-64. [PMID: 23062884 DOI: 10.1016/j.dnarep.2012.09.004] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Revised: 09/08/2012] [Accepted: 09/11/2012] [Indexed: 11/23/2022]
Abstract
S(N)1 DNA methylating agents are genotoxic agents that methylate numerous nucleophilic centers within DNA including the O(6) position of guanine (O(6)meG). Methylation of this extracyclic oxygen forces mispairing with thymine during DNA replication. The mismatch repair (MMR) system recognizes these O(6)meG:T mispairs and is required to activate DNA damage response (DDR). Exonuclease I (EXO1) is a key component of MMR by resecting the damaged strand; however, whether EXO1 is required to activate MMR-dependent DDR remains unknown. Here we show that knockdown of the mouse ortholog (mExo1) in mouse embryonic fibroblasts (MEFs) results in decreased G2/M checkpoint response, limited effects on cell proliferation, and increased cell viability following exposure to the S(N)1 methylating agent N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), establishing a phenotype paralleling MMR deficiency. MNNG treatment induced formation of γ-H2AX foci with which EXO1 co-localized in MEFs, but mExo1-depleted MEFs displayed a significant diminishment of γ-H2AX foci formation. mExo1 depletion also reduced MSH2 association with DNA duplexes containing G:T mismatches in vitro, decreased MSH2 association with alkylated chromatin in vivo, and abrogated MNNG-induced MSH2/CHK1 interaction. To determine if nuclease activity is required to activate DDR we stably overexpressed a nuclease defective form of human EXO1 (hEXO1) in mExo1-depleted MEFs. These experiments indicated that expression of wildtype and catalytically null hEXO1 was able to restore normal response to MNNG. This study indicates that EXO1 is required to activate MMR-dependent DDR in response to S(N)1 methylating agents; however, this function of EXO1 is independent of its nucleolytic activity.
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Wang J, Fan HC, Behr B, Quake SR. Genome-wide single-cell analysis of recombination activity and de novo mutation rates in human sperm. Cell 2012; 150:402-12. [PMID: 22817899 DOI: 10.1016/j.cell.2012.06.030] [Citation(s) in RCA: 362] [Impact Index Per Article: 30.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Revised: 05/31/2012] [Accepted: 06/13/2012] [Indexed: 02/01/2023]
Abstract
Meiotic recombination and de novo mutation are the two main contributions toward gamete genome diversity, and many questions remain about how an individual human's genome is edited by these two processes. Here, we describe a high-throughput method for single-cell whole-genome analysis that was used to measure the genomic diversity in one individual's gamete genomes. A microfluidic system was used for highly parallel sample processing and to minimize nonspecific amplification. High-density genotyping results from 91 single cells were used to create a personal recombination map, which was consistent with population-wide data at low resolution but revealed significant differences from pedigree data at higher resolution. We used the data to test for meiotic drive and found evidence for gene conversion. High-throughput sequencing on 31 single cells was used to measure the frequency of large-scale genome instability, and deeper sequencing of eight single cells revealed de novo mutation rates with distinct characteristics.
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Affiliation(s)
- Jianbin Wang
- Department of Bioengineering, Stanford University, Stanford, CA 94305, USA
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29
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Zhang N, Wu X, Yang L, Xiao F, Zhang H, Zhou A, Huang Z, Huang S. FoxM1 inhibition sensitizes resistant glioblastoma cells to temozolomide by downregulating the expression of DNA-repair gene Rad51. Clin Cancer Res 2012; 18:5961-71. [PMID: 22977194 DOI: 10.1158/1078-0432.ccr-12-0039] [Citation(s) in RCA: 87] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
PURPOSE Recurrent glioblastoma multiforme (GBM) is characterized by resistance to radiotherapy and chemotherapy and a poor clinical prognosis. In this study, we investigated the role of the oncogenic transcription factor FoxM1 in GBM cells' resistance to alkylator temozolomide (TMZ) and its potential molecular mechanism. EXPERIMENTAL DESIGN FoxM1 expression levels were measured by immunohistochemical analysis in 38 pairs of primary and recurrent GBM tumor samples. Expression levels were also measured in primary recurrent GBM cell lines, and their responses to TMZ were characterized. In a mechanistic study, an siRNA array was used to identify downstream genes, and a chromatin immunoprecipitation assay was used to confirm transcriptional regulation. RESULTS Recurrent tumors that were TMZ resistant expressed higher levels of FoxM1 than did primary tumors. Recurrent GBM cell lines expressed higher levels of FoxM1 and the DNA damage repair gene Rad51 and were resistant to TMZ. TMZ treatment led to increased FoxM1 and Rad51 expression. FoxM1 knockdown inhibited Rad51 expression and sensitized recurrent GBM cells to TMZ cytotoxicity. FoxM1 directly regulated Rad51 expression through 2 FoxM1-specific binding sites in its promoter. Rad51 reexpression partially rescued TMZ resistance in FoxM1-knockdown recurrent GBM cells. A direct correlation between FoxM1 expression and Rad51 expression was evident in recurrent GBM tumor samples. CONCLUSION Targeting the FoxM1-Rad51 axis may be an effective method to reverse TMZ resistance in recurrent GBM.
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Affiliation(s)
- Nu Zhang
- Department of Neurosurgery, Scientific Research Section, The First Affiliated Hospital of Sun Yat-sen University, Guangzhou, Guangdong Province, PR China
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30
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AIDing antibody diversity by error-prone mismatch repair. Semin Immunol 2012; 24:293-300. [PMID: 22703640 DOI: 10.1016/j.smim.2012.05.005] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Accepted: 05/18/2012] [Indexed: 11/20/2022]
Abstract
The creation of a highly diverse antibody repertoire requires the synergistic activity of a DNA mutator, known as activation-induced deaminase (AID), coupled with an error-prone repair process that recognizes the DNA mismatch catalyzed by AID. Instead of facilitating the canonical error-free response, which generally occurs throughout the genome, DNA mismatch repair (MMR) participates in an error-prone repair mode that promotes A:T mutagenesis and double-strand breaks at the immunoglobulin (Ig) genes. As such, MMR is capable of compounding the mutation frequency of AID activity as well as broadening the spectrum of base mutations; thereby increasing the efficiency of antibody maturation. We here review the current understanding of this MMR-mediated process and describe how the MMR signaling cascade downstream of AID diverges in a locus dependent manner and even within the Ig locus itself to differentially promote somatic hypermutation (SHM) and class switch recombination (CSR) in B cells.
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31
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Goellner EM, Grimme B, Brown AR, Lin YC, Wang XH, Sugrue KF, Mitchell L, Trivedi RN, Tang JB, Sobol RW. Overcoming temozolomide resistance in glioblastoma via dual inhibition of NAD+ biosynthesis and base excision repair. Cancer Res 2011; 71:2308-17. [PMID: 21406402 DOI: 10.1158/0008-5472.can-10-3213] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Glioblastoma multiforme (GBM) is a devastating brain tumor with poor prognosis and low median survival time. Standard treatment includes radiation and chemotherapy with the DNA alkylating agent temozolomide (TMZ). However, a large percentage of tumors are resistant to the cytotoxic effects of the TMZ-induced DNA lesion O(6)-methylguanine due to elevated expression of the repair protein O(6)-methylguanine-DNA methyltransferase (MGMT) or a defect in the mismatch repair (MMR) pathway. Although a majority of the TMZ-induced lesions (N7-methylguanine and N3-methyladenine) are base excision repair (BER) substrates, these DNA lesions are also readily repaired. However, blocking BER can enhance response to TMZ and therefore the BER pathway has emerged as an attractive target for reversing TMZ resistance. Our lab has recently reported that inhibition of BER leads to the accumulation of repair intermediates that induce energy depletion-mediated cell death via hyperactivation of poly(ADP-ribose) polymerase. On the basis of our observation that TMZ-induced cell death via BER inhibition is dependent on the availability of nicotinamide adenine dinucleotide (NAD(+)), we have hypothesized that combined BER and NAD(+) biosynthesis inhibition will increase TMZ efficacy in glioblastoma cell lines greater than BER inhibition alone. Importantly, we find that the combination of BER and NAD(+) biosynthesis inhibition significantly sensitizes glioma cells with elevated expression of MGMT and those deficient in MMR, two genotypes normally associated with TMZ resistance. Dual targeting of these two interacting pathways (DNA repair and NAD(+) biosynthesis) may prove to be an effective treatment combination for patients with resistant and recurrent GBM.
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Affiliation(s)
- Eva M Goellner
- Department of Pharmacology and Chemical Biology, University of Pittsburgh School of Medicine, and University of Pittsburgh Cancer Institute, Hillman Cancer Center, Pittsburgh, Pennsylvania 15213-1863, USA
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32
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Abbà S, Vallino M, Daghino S, Di Vietro L, Borriello R, Perotto S. A PLAC8-containing protein from an endomycorrhizal fungus confers cadmium resistance to yeast cells by interacting with Mlh3p. Nucleic Acids Res 2011; 39:7548-63. [PMID: 21672957 PMCID: PMC3177179 DOI: 10.1093/nar/gkr336] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Cadmium is a genotoxic pollutant known to target proteins that are involved in DNA repair and in antioxidant defence, altering their functions and ultimately causing mutagenic and carcinogenic effects. We have identified a PLAC8 domain-containing protein, named OmFCR, by a yeast functional screen aimed at identifying genes involved in cadmium resistance in the endomycorrhizal fungus Oidiodendron maius. OmFCR shows a remarkable specificity in mediating cadmium resistance. Both its function and its nuclear localization in yeast strictly depend on the interaction with Mlh3p, a subunit of the mismatch repair (MMR) system. Although proteins belonging to the PLAC8 family are widespread in eukaryotes, they are poorly characterized and their biological role still remains elusive. Our work represents the first report about the potential role of a PLAC8 protein in physically coupling DNA lesion recognition by the MMR system to appropriate effectors that affect cell cycle checkpoint pathways. On the basis of cell survival assays and yeast growth curves, we hypothesize that, upon cadmium exposure, OmFCR might promote a higher rate of cell division as compared to control cells.
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Affiliation(s)
- S Abbà
- Dipartimento di Biologia Vegetale dell'Università degli Studi di Torino, Viale Mattioli 25, Torino, Italy.
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Pabla N, Ma Z, McIlhatton MA, Fishel R, Dong Z. hMSH2 recruits ATR to DNA damage sites for activation during DNA damage-induced apoptosis. J Biol Chem 2011; 286:10411-8. [PMID: 21285353 DOI: 10.1074/jbc.m110.210989] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
DNA damage response (DDR) activates a complex signaling network that triggers DNA repair, cell cycle arrest, and/or cell death. Depending on the type and severity of DNA lesion, DDR is controlled by "master" regulators including ATM and ATR protein kinases. Cisplatin, a major chemotherapy drug that cross-links DNA, induces ATR-dependent DDR, resulting in apoptosis. However, it is unclear how ATR is activated. To identify the key regulators of ATR, we analyzed the proteins that associate with ATR after cisplatin treatment by blue native-PAGE and co-immunoprecipitation. The mismatch repair protein hMSH2 was found to be a major ATR-binding protein. Functionally, ATR activation and its recruitment to nuclear foci during cisplatin treatment were attenuated, and DNA damage signaling, involving Chk2, p53, and PUMA-α, was suppressed in hMSH2-deficient cells. ATR activation induced by the DNA methylating agent N-methyl-N-nitrosourea was also shown to be hMSH2-dependent. Intriguingly, hMSH2-mediated ATR recruitment and activation appeared independent of replication protein A, Rad17, and the Rad9-Hus1-Rad1 protein complex. Together the results support a hMSH2-dependent pathway of ATR activation and downstream Chk2/p53 signaling.
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Affiliation(s)
- Navjotsingh Pabla
- Department of Cellular Biology and Anatomy, Medical College of Georgia, Augusta, Georgia 30912, USA
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Preston BD, Albertson TM, Herr AJ. DNA replication fidelity and cancer. Semin Cancer Biol 2010; 20:281-93. [PMID: 20951805 PMCID: PMC2993855 DOI: 10.1016/j.semcancer.2010.10.009] [Citation(s) in RCA: 105] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Accepted: 10/07/2010] [Indexed: 12/14/2022]
Abstract
Cancer is fueled by mutations and driven by adaptive selection. Normal cells avoid deleterious mutations by replicating their genomes with extraordinary accuracy. Here we review the pathways governing DNA replication fidelity and discuss evidence implicating replication errors (point mutation instability or PIN) in carcinogenesis.
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Affiliation(s)
- Bradley D Preston
- Department of Pathology, University of Washington, Seattle, WA 98195, USA.
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Martin SA, Lord CJ, Ashworth A. Therapeutic targeting of the DNA mismatch repair pathway. Clin Cancer Res 2010; 16:5107-13. [PMID: 20823149 DOI: 10.1158/1078-0432.ccr-10-0821] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The mismatch repair (MMR) pathway is involved in the removal of DNA base mismatches that arise either during DNA replication or are caused by DNA damage. Mutations in four genes involved in MMR, MSH2, MLH1, PMS2 and MSH6, predispose to a range of tumorigenic conditions, including hereditary nonpolyposis colon cancer, also known as Lynch syndrome. Here we discuss the canonical MMR pathway and the burgeoning evidence for noncanonical roles for the MMR genes, and highlight the therapeutic implications of MMR. In particular, we discuss how the DNA repair defect in MMR-deficient cancers could be exploited by the development of novel therapeutic strategies based on synthetic lethal approaches.
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Affiliation(s)
- Sarah A Martin
- Cancer Research UK Gene Function and Regulation Group, The Institute of Cancer Research, London, United Kingdom
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36
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Polosina YY, Cupples CG. Wot the 'L-Does MutL do? Mutat Res 2010; 705:228-38. [PMID: 20667509 DOI: 10.1016/j.mrrev.2010.07.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2010] [Revised: 07/13/2010] [Accepted: 07/14/2010] [Indexed: 11/26/2022]
Abstract
In model DNA, A pairs with T, and C with G. However, in vivo, the complementarity of the DNA strands may be disrupted by errors in DNA replication, biochemical modification of bases and recombination. In prokaryotic organisms, mispaired bases are recognized by MutS homologs which, together with MutL homologs, initiate mismatch repair. These same proteins also participate in base excision repair and nucleotide excision repair. In eukaryotes they regulate not just DNA repair but also meiotic recombination, cell-cycle delay and/or apoptosis in response to DNA damage, and hypermutation in immunoglobulin genes. Significantly, the same DNA mismatches that trigger repair in some circumstances trigger non-repair pathways in others. In this review, we argue that mismatch recognition by the MutS proteins is linked to these disparate biological outcomes through regulated interaction of MutL proteins with a wide variety of effector proteins.
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Affiliation(s)
- Yaroslava Y Polosina
- Department of Biochemistry and Microbiology, University of Victoria, PO Box 3055, STN CSC, Victoria, BC, Canada.
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37
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Cheng F, Hou J, Chen YY, Zhou Y, Zhang HT, Bi LJ, Zhang XE. Functional interaction between MutL and 3'-5' exonuclease X in Escherichia coli. Arch Biochem Biophys 2010; 502:39-43. [PMID: 20638361 DOI: 10.1016/j.abb.2010.07.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/09/2010] [Accepted: 07/11/2010] [Indexed: 12/16/2022]
Abstract
Exonuclease X is a 3'-5' distributive exonuclease that functions in DNA recombination and repair. It undergoes multiple rounds of binding, hydrolysis, and release to degrade long substrate molecules and thus is very inefficient. In order to identify a cofactor that elevates the excision activity of ExoX, we screened many proteins involved in repair and recombination. We observed that MutL greatly promoted the exonuclease activity of ExoX, and then verified the interaction between MutL and ExoX using SPR and Far-Western analysis. This promotion is independent of ATP and the DNA-binding activity of MutL. We constructed two deletion mutants to analyze this interaction and its regulation of ExoX activity, and found that this functional interaction with ExoX is mainly due to ionic interactions with the N-terminus of MutL. This adds a new role to MutL and gives a clue to MutL's possible regulation on other DnaQ family exonuclease members.
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Affiliation(s)
- Fang Cheng
- National Laboratory of Biomacromolecules and Proteomics Platform, Institute of Biophysics, Chinese Academy of Sciences, Beijing 100101, China
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38
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McEllin B, Camacho CV, Mukherjee B, Hahm B, Tomimatsu N, Bachoo RM, Burma S. PTEN loss compromises homologous recombination repair in astrocytes: implications for glioblastoma therapy with temozolomide or poly(ADP-ribose) polymerase inhibitors. Cancer Res 2010; 70:5457-64. [PMID: 20530668 PMCID: PMC2896430 DOI: 10.1158/0008-5472.can-09-4295] [Citation(s) in RCA: 189] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Glioblastomas (GBM) are lethal brain tumors that are highly resistant to therapy. The only meaningful improvement in therapeutic response came from use of the S(N)1-type alkylating agent temozolomide in combination with ionizing radiation. However, no genetic markers that might predict a better response to DNA alkylating agents have been identified in GBMs, except for loss of O(6-)methylguanine-DNA methyltransferase via promoter methylation. In this study, using genetically defined primary murine astrocytes as well as human glioma lines, we show that loss of phosphatase and tensin homolog deleted on chromosome 10 (PTEN) confers sensitivity to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a functional analogue of temozolomide. We find that MNNG induces replication-associated DNA double-strand breaks (DSB), which are inefficiently repaired in PTEN-deficient astrocytes and trigger apoptosis. Mechanistically, this is because PTEN-null astrocytes are compromised in homologous recombination (HR), which is important for the repair of replication-associated DSBs. Our results suggest that reduced levels of Rad51 paralogs in PTEN-null astrocytes might underlie the HR deficiency of these cells. Importantly, the HR deficiency of PTEN-null cells renders them sensitive to the poly(ADP-ribose) polymerase (PARP) inhibitor ABT-888 due to synthetic lethality. In sum, our results tentatively suggest that patients with PTEN-null GBMs (about 36%) may especially benefit from treatment with DNA alkylating agents such as temozolomide. Significantly, our results also provide a rational basis for treating the subgroup of patients who are PTEN deficient with PARP inhibitors in addition to the current treatment regimen of radiation and temozolomide.
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Affiliation(s)
- Brian McEllin
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Cristel V. Camacho
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Bipasha Mukherjee
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Brandon Hahm
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Nozomi Tomimatsu
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Robert M. Bachoo
- Department of Neurology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
| | - Sandeep Burma
- Department of Radiation Oncology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas
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39
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Bhonde MR, Hanski ML, Stehr J, Jebautzke B, Peiró-Jordán R, Fechner H, Yokoyama KK, Lin WC, Zeitz M, Hanski C. Mismatch repair system decreases cell survival by stabilizing the tetraploid G1 arrest in response to SN-38. Int J Cancer 2010; 126:2813-25. [PMID: 19739070 DOI: 10.1002/ijc.24893] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The role of the mismatch repair (MMR) system in correcting base-base mismatches is well established; its involvement in the response to DNA double strand breaks, however, is less clear. We investigated the influence of the essential component of MMR, the hMLH1 protein, on the cellular response to DNA-double strand breaks induced by treatment with SN-38, the active metabolite of topoisomerase I inhibitor irinotecan, in a strictly isogenic cell system (p53(wt), hMLH1(+)/p53(wt), hMLH1(-)). By using hMLH1 expressing clones or cells transduced with the hMLH1-expressing adenovirus as well as siRNA technology, we show that in response to SN-38-induced DNA damage the MMR proficient (MMR(+)) cells make: (i) a stronger G2/M arrest, (ii) a subsequent longer tetraploid G1 arrest, (iii) a stronger activation of Chk1 and Chk2 kinases than the MMR deficient (MMR(-)) counterparts. Both Cdk2 and Cdk4 kinases contribute to the basal tetraploid G1 arrest in MMR(+) and MMR(-) cells. Although the Chk1 kinase is involved in the G2/M arrest, neither Chk1 nor Chk2 are involved in the enhancement of the tetraploid G1 arrest. The long-lasting tetraploid G1 arrest of MMR(+) cells is associated with their lower clonogenic survival after SN-38 treatment, the abrogation of the tetraploid G1 arrest resulted in their better clonogenic survival. These data show that the stabilization of the tetraploid G1 arrest in response to double strand breaks is a novel function of the MMR system that contributes to the lesser survival of MMR(+) cells.
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Affiliation(s)
- Mandar Ramesh Bhonde
- Department of Gastroenterology, Charité, Campus Benjamin Franklin, Berlin, Germany
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40
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Polosina YY, Cupples CG. MutL: conducting the cell's response to mismatched and misaligned DNA. Bioessays 2010; 32:51-9. [PMID: 19953589 DOI: 10.1002/bies.200900089] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Base pair mismatches in DNA arise from errors in DNA replication, recombination, and biochemical modification of bases. Mismatches are inherently transient. They are resolved passively by DNA replication, or actively by enzymatic removal and resynthesis of one of the bases. The first step in removal is recognition of strand discontinuity by one of the MutS proteins. Mismatches arising from errors in DNA replication are repaired in favor of the base on the template strand, but other mismatches trigger base excision or nucleotide excision repair (NER), or non-repair pathways such as hypermutation, cell cycle arrest, or apoptosis. We argue that MutL homologues play a key role in determining biologic outcome by recruiting and/or activating effector proteins in response to lesion recognition by MutS. We suggest that the process is regulated by conformational changes in MutL caused by cycles of ATP binding and hydrolysis, and by physiologic changes which influence effector availability.
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Affiliation(s)
- Yaroslava Y Polosina
- Department of Biochemistry and Microbiology, University of Victoria, BC, Canada.
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41
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van de Vrugt HJ, Eaton L, Hanlon Newell A, Al-Dhalimy M, Liskay RM, Olson SB, Grompe M. Embryonic lethality after combined inactivation of Fancd2 and Mlh1 in mice. Cancer Res 2010; 69:9431-8. [PMID: 19934329 DOI: 10.1158/0008-5472.can-09-2452] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
DNA repair defects are frequently encountered in human cancers. These defects are utilized by traditional therapeutics but also offer novel cancer treatment strategies based on synthetic lethality. To determine the consequences of combined Fanconi anemia (FA) and mismatch repair pathway inactivation, defects in Fancd2 and Mlh1 were combined in one mouse model. Fancd2/Mlh1 double-mutant embryos displayed growth retardation resulting in embryonic lethality and significant underrepresentation among progeny. Additional inactivation of Trp53 failed to improve the survival of Fancd2/Mlh1-deficient embryos. Mouse fibroblasts were obtained and challenged with cross-linking agents. Fancd2-deficient cells displayed the FA-characteristic growth inhibition after mitomycin C (MMC) exposure. In primary fibroblasts, the absence of Mlh1 did not greatly affect the MMC sensitivity of Fancd2-deficient and Fancd2-proficient cells. However, in Trp53 mutant immortalized fibroblasts, Mlh1 deficiency reduced the growth-inhibiting effect of MMC in Fancd2 mutant and complemented cells. Similar data were obtained using psoralen/UVA, signifying that MLH1 influences the cellular sensitivity to DNA interstrand cross-links. Next, the effect of MLH1 deficiency on the formation of chromosomal aberrations in response to cross-linking agents was determined. Surprisingly, Mlh1 mutant fibroblasts displayed a modest but noticeable decrease in induced chromosomal breakage and interchange frequencies, suggesting that MLH1 promotes interstrand cross-link repair catastrophe. In conclusion, the combined inactivation of Fancd2 and Mlh1 did not result in synthetic lethality at the cellular level. Although the absence of Fancd2 sensitized Mlh1/Trp53 mutant fibroblasts to MMC, the differential survival of primary and immortalized fibroblasts advocates against systemic inactivation of FANCD2 to enhance treatment of MLH1-deficient tumors.
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Affiliation(s)
- Henri J van de Vrugt
- Oregon Stem Cell Center, Oregon Health and Science University, Portland, Oregon, USA.
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Martin L, Marples B, Coffey M, Lawler M, Hollywood D, Marignol L. Recognition of O6MeG lesions by MGMT and mismatch repair proficiency may be a prerequisite for low-dose radiation hypersensitivity. Radiat Res 2009; 172:405-13. [PMID: 19772461 DOI: 10.1667/rr1717.1] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Low-dose hyper-radiosensitivity (HRS) is the phenomenon whereby cells exposed to radiation doses of less than approximately 0.5 Gy exhibit increased cell killing relative to that predicted from back-extrapolating high-dose survival data using a linear-quadratic model. While the exact mechanism remains to be elucidated, the involvement of several molecular repair pathways has been documented. These processes in turn are also associated with the response of cells to O6-methylguanine (O6MeG) lesions. We propose a model in which the level of low-dose cell killing is determined by the efficiency of both pre-replicative repair by the DNA repair enzyme O6-methylguanine methyltransferase (MGMT) and post-replicative repair by the DNA mismatch repair (MMR) system. We therefore hypothesized that the response of cells to low doses of radiation is dependent on the expression status of MGMT and MMR proteins. MMR (MSH2, MSH6, MLH1, PMS1, PMS2) and MGMT protein expression signatures were determined in a panel of normal (PWR1E, RWPE1) and malignant (22RV1, DU145, PC3) prostate cell lines and correlated with clonogenic survival and cell cycle analysis. PC3 and RWPE1 cells (HRS positive) were associated with MGMT and MMR proficiency, whereas HRS negative cell lines lacked expression of at least one (MGMT or MMR) protein. MGMT inactivation had no significant effect on cell survival. These results indicate a possible role for MMR-dependent processing of damage produced by low doses of radiation.
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Affiliation(s)
- Lynn Martin
- Division of Radiation Therapy, Trinity College Dublin, Dublin, Ireland.
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Affiliation(s)
- Mats Ljungman
- Division of Radiation and Cancer Biology, Department of Radiation Oncology, University of Michigan Comprehensive Cancer Center, Ann Arbor, Michigan 48109, USA.
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Li LS, Morales JC, Veigl M, Sedwick D, Greer S, Meyers M, Wagner M, Fishel R, Boothman DA. DNA mismatch repair (MMR)-dependent 5-fluorouracil cytotoxicity and the potential for new therapeutic targets. Br J Pharmacol 2009; 158:679-92. [PMID: 19775280 DOI: 10.1111/j.1476-5381.2009.00423.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The metabolism and efficacy of 5-fluorouracil (FUra) and other fluorinated pyrimidine (FP) derivatives have been intensively investigated for over fifty years. FUra and its antimetabolites can be incorporated at RNA- and DNA-levels, with RNA level incorporation provoking toxic responses in human normal tissue, and DNA-level antimetabolite formation and incorporation believed primarily responsible for tumour-selective responses. Attempts to direct FUra into DNA-level antimetabolites, based on mechanism-of-action studies, have led to gradual improvements in tumour therapy. These include the use of leukovorin to stabilize the inhibitory thymidylate synthase-5-fluoro-2'-deoxyuridine 5' monophoshate (FdUMP)-5,10-methylene tetrahydrofolate (5,10-CH(2)FH(4)) trimeric complex. FUra incorporated into DNA also contributes to antitumour activity in preclinical and clinical studies. This review examines our current state of knowledge regarding the mechanistic aspects of FUra:Gua lesion detection by DNA mismatch repair (MMR) machinery that ultimately results in lethality. MMR-dependent direct cell death signalling or futile cycle responses will be discussed. As 10-30% of sporadic colon and endometrial tumours display MMR defects as a result of human MutL homologue-1 (hMLH1) promoter hypermethylation, we discuss the use and manipulation of the hypomethylating agent, 5-fluorodeoxycytidine (FdCyd), and our ability to manipulate its metabolism using the cytidine or deoxycytidylate (dCMP) deaminase inhibitors, tetrahydrouridine or deoxytetrahydrouridine, respectively, as a method for re-expression of hMLH1 and re-sensitization of tumours to FP therapy.
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Affiliation(s)
- Long Shan Li
- Simmons Comprehensive Cancer Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
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45
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Di Cecco L, Melissari E, Mariotti V, Iofrida C, Galli A, Guidugli L, Lombardi G, Caligo MA, Iacopetti P, Pellegrini S. Characterisation of gene expression profiles of yeast cells expressing BRCA1 missense variants. Eur J Cancer 2009; 45:2187-96. [DOI: 10.1016/j.ejca.2009.04.025] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2009] [Revised: 04/15/2009] [Accepted: 04/24/2009] [Indexed: 11/25/2022]
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Pan J, Keffer J, Emami A, Ma X, Lan R, Goldman R, Chung FL. Acrolein-derived DNA adduct formation in human colon cancer cells: its role in apoptosis induction by docosahexaenoic acid. Chem Res Toxicol 2009; 22:798-806. [PMID: 19341237 DOI: 10.1021/tx800355k] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The apoptotic effects of docosahexaenoic acid (DHA) and other omega-3 polyunsaturated fatty acids (PUFAs) have been documented in cell and animal studies. The molecular mechanism by which DHA induces apoptosis is unclear. Although there is no direct evidence, some studies have suggested that DNA damage generated through lipid peroxidation may be involved. Our previous studies showed that DHA, because it has a high degree of unsaturation, can give rise to the acrolein-derived 1,N(2)-propanodeoxyguanosine (Acr-dG) as a major class of DNA adducts via lipid oxidation. As a first step to investigate the possible role of oxidative DNA damage in apoptosis induced by DHA, we examined the relationships between oxidative DNA damage and apoptosis caused by DHA in human colon cancer HT-29 cells. Apoptosis and oxidative DNA damage, including Acr-dG and 8-oxo-deoxyguanosine (8-oxo-dG) formation, in cells treated with DHA and omega-6 PUFAs, including arachidonic acid (AA) and linoleic acid (LA), were measured. DHA induced apoptosis in a dose- and time-dependent manner with a concentration range from 0 to 300 microM as indicated by increased caspase-3 activity and PARP cleavage. In contrast, AA and LA had little or no effect at these concentrations. The Acr-dG levels were increased in HT-29 cells treated with DHA at 240 and 300 microM, and the increases were correlated with the induction of apoptosis at these concentrations, while no significant changes were observed for 8-oxo-dG. Because proteins may compete with DNA to react with acrolein, we then examined the effects of BSA on DHA-induced apoptosis and oxidative DNA damage. The addition of BSA to HT-29 cell culture media significantly decreases Acr-dG levels with a concomitant decrease in the apoptosis induced by DHA. The reduced Acr-dG formation is attributed to the reaction of BSA with acrolein as indicated by increased levels of total protein carbonyls. Similar correlations between Acr-dG formation and apoptosis were observed in HT-29 cells directly incubated with 0-200 microM acrolein. Additionally, DHA treatment increased the level of DNA strand breaks and caused cell cycle arrested at G1 phase. Taken together, these results demonstrate the parallel relationships between Acr-dG level and apoptosis in HT-29 cells, suggesting that the formation of Acr-dG in cellular DNA may contribute to apoptosis induced by DHA.
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Affiliation(s)
- Jishen Pan
- Lombardi Comprehensive Cancer Center, Georgetown University, 3800 Reservoir Road NW, Washington, DC 20057, USA
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Altieri F, Grillo C, Maceroni M, Chichiarelli S. DNA damage and repair: from molecular mechanisms to health implications. Antioxid Redox Signal 2008; 10:891-937. [PMID: 18205545 DOI: 10.1089/ars.2007.1830] [Citation(s) in RCA: 133] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
DNA is subjected to several modifications, resulting from endogenous and exogenous sources. The cell has developed a network of complementary DNA-repair mechanisms, and in the human genome, >130 genes have been found to be involved. Knowledge about the basic mechanisms for DNA repair has revealed an unexpected complexity, with overlapping specificity within the same pathway, as well as extensive functional interactions between proteins involved in repair pathways. Unrepaired or improperly repaired DNA lesions have serious potential consequences for the cell, leading to genomic instability and deregulation of cellular functions. A number of disorders or syndromes, including several cancer predispositions and accelerated aging, are linked to an inherited defect in one of the DNA-repair pathways. Genomic instability, a characteristic of most human malignancies, can also arise from acquired defects in DNA repair, and the specific pathway affected is predictive of types of mutations, tumor drug sensitivity, and treatment outcome. Although DNA repair has received little attention as a determinant of drug sensitivity, emerging knowledge of mutations and polymorphisms in key human DNA-repair genes may provide a rational basis for improved strategies for therapeutic interventions on a number of tumors and degenerative disorders.
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Affiliation(s)
- Fabio Altieri
- Department of Biochemical Sciences, A. Rossi Fanelli, University La Sapienza, Rome, Italy.
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MDM2 SNP309 and TP53 Arg72Pro interact to alter therapy-related acute myeloid leukemia susceptibility. Blood 2008; 112:741-9. [PMID: 18426989 DOI: 10.1182/blood-2007-11-126508] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The p53 tumor suppressor directs the cellular response to many mechanistically distinct DNA-damaging agents and is selected against during the pathogenesis of therapy-related acute myeloid leukemia (t-AML). We hypothesized that constitutional genetic variation in the p53 pathway would affect t-AML risk. Therefore, we tested associations between patients with t-AML (n = 171) and 2 common functional p53-pathway variants, the MDM2 SNP309 and the TP53 codon 72 polymorphism. Although neither polymorphism alone influenced the risk of t-AML, an interactive effect was detected such that MDM2 TT TP53 Arg/Arg double homozygotes, and individuals carrying both a MDM2 G allele and a TP53 Pro allele, were at increased risk of t-AML (P value for interaction is .009). This interactive effect was observed in patients previously treated with chemotherapy but not in patients treated with radiotherapy, and in patients with loss of chromosomes 5 and/or 7, acquired abnormalities associated with prior exposure to alkylator chemotherapy. In addition, there was a trend toward shorter latency to t-AML in MDM2 GG versus TT homozygotes in females but not in males, and in younger but not older patients. These data indicate that the MDM2 and TP53 variants interact to modulate responses to genotoxic therapy and are determinants of risk for t-AML.
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Caporali S, Levati L, Starace G, Ragone G, Bonmassar E, Alvino E, D'Atri S. AKT Is Activated in an Ataxia-Telangiectasia and Rad3-Related-Dependent Manner in Response to Temozolomide and Confers Protection against Drug-Induced Cell Growth Inhibition. Mol Pharmacol 2008; 74:173-83. [DOI: 10.1124/mol.107.044743] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Zeng X, Kinsella TJ. Mammalian Target of Rapamycin and S6 Kinase 1 Positively Regulate 6-thioguanine-Induced Autophagy. Cancer Res 2008; 68:2384-90. [DOI: 10.1158/0008-5472.can-07-6163] [Citation(s) in RCA: 88] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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