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Madkour MM, Ramadan WS, Saleh E, El-Awady R. Epigenetic modulations in cancer: predictive biomarkers and potential targets for overcoming the resistance to topoisomerase I inhibitors. Ann Med 2023; 55:2203946. [PMID: 37092854 PMCID: PMC10128461 DOI: 10.1080/07853890.2023.2203946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/25/2023] Open
Abstract
INTRODUCTION Altered epigenetic map is frequently observed in cancer and recent investigations have demonstrated a pertinent role of epigenetic modifications in the response to many anticancer drugs including the DNA damaging agents. Topoisomerase I (Top I) is a well-known nuclear enzyme that is critical for DNA function and cell survival and its inhibition causes DNA strand breaks and cell cycle arrest. Inhibitors of human Top I have proven to be a prosperous chemotherapeutic treatment for a vast number of cancer patients. While the treatment is efficacious in many cases, resistance and altered cellular response remain major therapeutic issues. AREAS COVERED This review highlights the evidence available till date on the influence of different epigenetic modifications on the response to Top I inhibitors as well as the implications of targeting epigenetic alterations for improving the efficacy and safety of Top I inhibitors. EXPERT OPINION The field of epigenetic research is steadily growing. With its assistance, we could gain better understanding on how drug response and resistance work. Epigenetics can evolve as possible biomarkers and predictors of response to many medications including Top I inhibitors, and could have significant clinical implications that necessitate deeper attention.HIGHLIGHTSEpigenetic alterations, including DNA methylation and histone modifications, play a pertinent role in the response to several anticancer treatments, including DNA damaging agents like Top I inhibitors.Although camptothecin derivatives are used clinically as Top I inhibitors for management of cancer, certain types of cancer have inherent and or acquired resistance that limit the curative potential of them.Epigenetic modifications like DNA hypomethylation can either increase or decrease sensitivity to Top I inhibitors by different mechanisms.The combination of Top I inhibitors with the inhibitors of histone modifying enzymes can result in enhanced cytotoxic effects and sensitization of resistant cells to Top I inhibitors.MicroRNAs were found to directly influence the expression of Top I and other proteins in cancer cells resulting in positive or negative alteration of the response to Top I inhibitors.lncRNAs and their genetic polymorphisms have been found to be associated with Top I function and the response to its inhibitors.Clinical trials of epigenetic drugs in combination with Top I inhibitors are plentiful and some of them showed potentially promising outcomes.
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Affiliation(s)
- Moustafa M Madkour
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
| | - Wafaa S Ramadan
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Ekram Saleh
- Clinical Biochemistry and Molecular Biology Unit, Cancer Biology Department, National Cancer Institute, Cairo University, Cairo, Egypt
| | - Raafat El-Awady
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
- College of Pharmacy, University of Sharjah, Sharjah, United Arab Emirates
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Orta ML, Pastor N, Burgos-Morón E, Domínguez I, Calderón-Montaño JM, Huertas Castaño C, López-Lázaro M, Helleday T, Mateos S. Zebularine induces replication-dependent double-strand breaks which are preferentially repaired by homologous recombination. DNA Repair (Amst) 2017; 57:116-124. [PMID: 28732309 DOI: 10.1016/j.dnarep.2017.07.002] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Revised: 06/30/2017] [Accepted: 07/06/2017] [Indexed: 12/19/2022]
Abstract
Zebularine is a second-generation, highly stable hydrophilic inhibitor of DNA methylation with oral bioavailability that preferentially target cancer cells. It acts primarily as a trap for DNA methyl transferases (DNMTs) protein by forming covalent complexes between DNMT protein and zebularine-substrate DNA. It's well documented that replication-blocking DNA lesions can cause replication fork collapse and thereby to the formation of DNA double-strand breaks (DSB). DSB are dangerous lesions that can lead to potentially oncogenic genomic rearrangements or cell death. The two major pathways for repair of DSB are non-homologous end joining (NHEJ) and homologous recombination (HR). Recently, multiple functions for the HR machinery have been identified at arrested forks. Here we investigate in more detail the importance of the lesions induced by zebularine in terms of DNA damage and cytotoxicity as well as the role of HR in the repair of these lesions. When we examined the contribution of NHEJ and HR in the repair of DSB induced by zebularine we found that these breaks were preferentially repaired by HR. Also we show that the production of DSB is dependent on active replication. To test this, we determined chromosome damage by zebularine while transiently inhibiting DNA synthesis. Here we report that cells deficient in single-strand break (SSB) repair are hypersensitive to zebularine. We have observed more DSB induced by zebularine in XRCC1 deficient cells, likely to be the result of conversion of SSB into toxic DSB when encountered by a replication fork. Furthermore we demonstrate that HR is required for the repair of these breaks. Overall, our data suggest that zebularine induces replication-dependent DSB which are preferentially repaired by HR.
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Affiliation(s)
- Manuel Luis Orta
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain,.
| | - Nuria Pastor
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain
| | - Estefanía Burgos-Morón
- Department of Pharmacology, Faculty of Pharmacy, University of Seville, c/Professor García González, No. 2, 41012, Seville, Spain
| | - Inmaculada Domínguez
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain
| | - José Manuel Calderón-Montaño
- Department of Pharmacology, Faculty of Pharmacy, University of Seville, c/Professor García González, No. 2, 41012, Seville, Spain
| | - Carlos Huertas Castaño
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain
| | - Miguel López-Lázaro
- Department of Pharmacology, Faculty of Pharmacy, University of Seville, c/Professor García González, No. 2, 41012, Seville, Spain
| | - Thomas Helleday
- Science for Life Laboratory, Division of Translational Medicine and Chemical Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, S-17121, Stockholm, Sweden
| | - Santiago Mateos
- Department of Cell Biology, University of Seville, Avda. Reina Mercedes 6, 41012 Seville, Spain,.
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Mateos S, Domínguez I, Pastor N, Cantero G, Cortés F. The DNA demethylating 5-azaC induces endoreduplication in cultured Chinese hamster cells. Mutat Res 2005; 578:33-42. [PMID: 16202795 DOI: 10.1016/j.mrfmmm.2005.02.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2004] [Revised: 02/09/2005] [Accepted: 02/18/2005] [Indexed: 11/18/2022]
Abstract
We have investigated the possible influence of 5-azacytidine (5-azaC) substitution for cytidine into DNA on topoisomerase II (topo II) function in chromosome segregation. The endpoint chosen has been the induction of endoreduplicated cells at mitosis showing diplochromosomes. Experiments were performed in the presence and absence of the cytidine analogue to assess the degree of 5-azaC-induced DNA hypomethylation, using differential cutting by restriction endonucleases Hpa II and Msp I. Using the pulsed-field gel electrophoresis (PFGE) technique, we have also observed a protective effect provided by 5-azaC treatment against DNA breakage induced by the topo II poison m-AMSA. Concentrations of 5-azaC shown as able to induce extensive DNA hypomethylation and capable to protect DNA from double-strand breaks induced by m-AMSA were used for our cytogenetic experiments to analyze chromosome segregation. Our results seem to indicate that the presence of 5-azaC in DNA induces a dose-dependent increase in the yield of endoreduplicated cells that parallels the levels of hypomethylation observed.
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Affiliation(s)
- Santiago Mateos
- Department of Cell Biology, Faculty of Biology, University of Seville, Avda Reina Mercedes 6, E-41012 Seville, Spain
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Godard T, Deslandes E, Sichel F, Poul JM, Gauduchon P. Detection of topoisomerase inhibitor-induced DNA strand breaks and apoptosis by the alkaline comet assay. Mutat Res 2002; 520:47-56. [PMID: 12297143 DOI: 10.1016/s1383-5718(02)00174-2] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The alkaline comet assay is able to identify in individual cells DNA strand breaks associated with different processes. Topoisomerase inhibitors, some of which are used as chemotherapeutic agents, stabilise topoisomerase-DNA cleavable complexes by stimulating DNA strand cleavage and inhibiting religation. This can result in the activation of stress-associated signalling pathways, inducing cell cycle arrest and activation of the biochemical cascade of apoptosis. The aim of our study was to assess the ability of the comet assay to detect stabilisation of cleavable complexes and induction of apoptosis by two topoisomerase II inhibitors, etoposide and ellipticine, and two topoisomerase I inhibitors, camptothecin and topotecan. The study was carried out on Chinese hamster ovary (CHO) cells, DC3F cells and DC3F/C-10, its camptothecin-resistant counterpart. The comet assay was able to identify stabilised cleavable complexes through the presence of DNA strand breaks after 1h treatment that disappeared within 24h after drug removal. Kinetics studies allowed to discriminate between these early DNA damages and DNA fragmentation related to apoptosis characterised by reappearance of DNA strand breaks 48h after treatment.
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Affiliation(s)
- Thierry Godard
- GRECAN and INSERM CJF 96-03, Université de Caen, and Laboratoire de Cancérologie Expérimentale, Centre François Baclesse, Route de Lion-sur-Mer, F-14076 Cedex 05, Caen, France
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Takahashi-Hyodo SA, Sakamoto-Hojo ET, Takahashi CS. Interaction effects of 5-azacytidine with topoisomerase II inhibitors on CHO cells, as detected by cytogenetic analysis. Mutat Res 1999; 431:13-23. [PMID: 10656482 DOI: 10.1016/s0027-5107(99)00151-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Different cell treatment protocols with the hypomethylating agent 5 azacytidine (5-aza C) were used in exponentially growing Chinese hamster ovary (CHO) cells in order to test its influence on the induction of chromosomal aberrations (CAs) induced by topoisomerase II inhibitors, ellipticine (EPC) and teniposide (VM-26). Cells pre-treated with 1 microg/ml 5-aza C for 1 h during the S-phase and post-treated in the last 2 h of incubation with 0.6 microg/ml EPC or 0.04 microg/ml VM-26 showed a reduction of 48% and 45%, respectively, in the frequencies of CAs as compared to the sum value of the frequencies obtained for each drug alone. 5-aza C added to the cultures for the last 2 h before cell fixation after a 30-min pulse treatment with EPC or VM-26 caused a 38% and 28% reduction, respectively. Simultaneous treatments with 5-aza C plus EPC, or 5-aza C plus VM-26 during the last 2 h of incubation (G2-phase), showed a significant effect of CA reduction (24%) only for the combination of 5-aza C + EPC. Preliminary assays with 5-aza C alone added to the cultures at different times demonstrated its effectiveness in inducing chromosome damage during the S-phase. Since S-phase-treated CHO cells showed a higher degree of reduction in the frequencies of CAs induced by EPC and VM-26, we suggest that 5-aza C incorporation into DNA may change the topo II cleavage sites, protecting the DNA from the induction of damage, or that the hypomethylation induced by incorporation of 5-aza C into DNA may change the chromatin structure facilitating the access to DNA repair enzymes. An alternative possibility is that 5-azaC can reactivate methylated genes involved in the repair of DNA double-strand breaks induced by topo II inhibitors.
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Affiliation(s)
- S A Takahashi-Hyodo
- Departamento de Genética e Matemática Aplicada à Biologia, Faculdade de Medicina de Ribeirão Preto - Universidad de São Paulo, Brazil
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