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Pužar Dominkuš P, Hudler P. Mutational Signatures in Gastric Cancer and Their Clinical Implications. Cancers (Basel) 2023; 15:3788. [PMID: 37568604 PMCID: PMC10416847 DOI: 10.3390/cancers15153788] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/23/2023] [Accepted: 07/24/2023] [Indexed: 08/13/2023] Open
Abstract
Gastric cancer is characterised by high inter- and intratumour heterogeneity. The majority of patients are older than 65 years and the global burden of this disease is increasing due to the aging of the population. The disease is usually diagnosed at advanced stages, which is a consequence of nonspecific symptoms. Few improvements have been made at the level of noninvasive molecular diagnosis of sporadic gastric cancer, and therefore the mortality rate remains high. A new field of mutational signatures has emerged in the past decade with advances in the genome sequencing technology. These distinct mutational patterns in the genome, caused by exogenous and endogenous mutational processes, can be associated with tumour aetiology and disease progression, and could provide novel perception on the treatment possibilities. This review assesses the mutational signatures found in gastric cancer and summarises their potential for use in clinical setting as diagnostic or prognostic biomarkers. Associated treatment options and biomarkers already implemented in clinical use are discussed, together with those that are still being explored or are in clinical studies.
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Affiliation(s)
- Pia Pužar Dominkuš
- Pharmacogenetics Laboratory, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia;
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
| | - Petra Hudler
- Medical Centre for Molecular Biology, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Vrazov trg 2, 1000 Ljubljana, Slovenia
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2
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Fernandes SG, Shah P, Khattar E. Recent Advances in Therapeutic Application of DNA Damage Response Inhibitors against Cancer. Anticancer Agents Med Chem 2021; 22:469-484. [PMID: 34102988 DOI: 10.2174/1871520621666210608105735] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Revised: 02/02/2021] [Accepted: 02/22/2021] [Indexed: 11/22/2022]
Abstract
DNA integrity is continuously challenged by intrinsic cellular processes and environmental agents. To overcome this genomic damage, cells have developed multiple signaling pathways collectively named as DNA damage response (DDR) and composed of three components: (i) sensor proteins, which detect DNA damage, (ii) mediators that relay the signal downstream and recruit the repair machinery, and (iii) the repair proteins, which restore the damaged DNA. A flawed DDR and failure to repair the damage lead to the accumulation of genetic lesions and increased genomic instability, which is recognized as a hallmark of cancer. Cancer cells tend to harbor increased mutations in DDR genes and often have fewer DDR pathways than normal cells. This makes cancer cells more dependent on particular DDR pathways and thus become more susceptible to compounds inhibiting those pathways compared to normal cells, which have all the DDR pathways intact. Understanding the roles of different DDR proteins in the DNA damage response and repair pathways and identification of their structures have paved the way for the development of their inhibitors as targeted cancer therapy. In this review, we describe the major participants of various DDR pathways, their significance in carcinogenesis, and focus on the inhibitors developed against several key DDR proteins.
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Affiliation(s)
- Stina George Fernandes
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
| | - Prachi Shah
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
| | - Ekta Khattar
- Sunandan Divatia School of Science, SVKM's NMIMS (Deemed to be) University, Mumbai, India
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3
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DNA-PK in human malignant disorders: Mechanisms and implications for pharmacological interventions. Pharmacol Ther 2020; 215:107617. [PMID: 32610116 DOI: 10.1016/j.pharmthera.2020.107617] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2020] [Accepted: 06/15/2020] [Indexed: 12/12/2022]
Abstract
The DNA-PK holoenzyme is a fundamental element of the DNA damage response machinery (DDR), which is responsible for cellular genomic stability. Consequently, and predictably, over the last decades since its identification and characterization, numerous pre-clinical and clinical studies reported observations correlating aberrant DNA-PK status and activity with cancer onset, progression and responses to therapeutic modalities. Notably, various studies have established in recent years the role of DNA-PK outside the DDR network, corroborating its role as a pleiotropic complex involved in transcriptional programs that operate biologic processes as epithelial to mesenchymal transition (EMT), hypoxia, metabolism, nuclear receptors signaling and inflammatory responses. In particular tumor entities as prostate cancer, immense research efforts assisted mapping and describing the overall signaling networks regulated by DNA-PK that control metastasis and tumor progression. Correspondingly, DNA-PK emerges as an obvious therapeutic target in cancer and data pertaining to various pharmacological approaches have been published, largely in context of combination with DNA-damaging agents (DDAs) that act by inflicting DNA double strand breaks (DSBs). Currently, new generation inhibitors are tested in clinical trials. Several excellent reviews have been published in recent years covering the biology of DNA-PK and its role in cancer. In the current article we are aiming to systematically describe the main findings on DNA-PK signaling in major cancer types, focusing on both preclinical and clinical reports and present a detailed current status of the DNA-PK inhibitors repertoire.
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Kostyushev D, Brezgin S, Kostyusheva A, Zarifyan D, Goptar I, Chulanov V. Orthologous CRISPR/Cas9 systems for specific and efficient degradation of covalently closed circular DNA of hepatitis B virus. Cell Mol Life Sci 2019; 76:1779-1794. [PMID: 30673820 PMCID: PMC11105500 DOI: 10.1007/s00018-019-03021-8] [Citation(s) in RCA: 44] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 01/16/2019] [Accepted: 01/17/2019] [Indexed: 12/11/2022]
Abstract
Covalently closed circular DNA (cccDNA) of hepatitis B virus (HBV) is the major cause of viral persistence and chronic hepatitis B. CRISPR/Cas9 nucleases can specifically target HBV cccDNA for decay, but off-target effects of nucleases in the human genome limit their clinical utility. CRISPR/Cas9 systems from four different species were co-expressed in cell lines with guide RNAs targeting conserved regions of the HBV genome. CRISPR/Cas9 systems from Streptococcus pyogenes (Sp) and Streptococcus thermophilus (St) targeting conserved regions of the HBV genome blocked HBV replication and, most importantly, resulted in degradation of over 90% of HBV cccDNA by 6 days post-transfection. Degradation of HBV cccDNA was impaired by inhibition of non-homologous end-joining pathway and resulted in an erroneous repair of HBV cccDNA. HBV cccDNA methylation also affected antiviral activity of CRISPR/Cas9. Single-nucleotide HBV genetic variants did not impact anti-HBV activity of St CRISPR/Cas9, suggesting its utility in targeting many HBV variants. However, two or more mismatches impaired or blocked CRISPR/Cas9 activity, indicating that host DNA will not likely be targeted. Deep sequencing revealed that Sp CRISPR/Cas9 induced off-target mutagenesis, whereas St CRISPR/Cas9 had no effect on the host genome. St CRISPR/Cas9 system represents the safest system with high anti-HBV activity.
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Affiliation(s)
- Dmitry Kostyushev
- Viral Hepatitis Laboratory, Central Research Institute of Epidemiology, 3A Novogireevskaya Street, Moscow, 111123, Russian Federation.
| | - Sergey Brezgin
- Viral Hepatitis Laboratory, Central Research Institute of Epidemiology, 3A Novogireevskaya Street, Moscow, 111123, Russian Federation
- Institute of Immunology, Federal Medical Biological Agency, Moscow, 115478, Russian Federation
| | - Anastasiya Kostyusheva
- Viral Hepatitis Laboratory, Central Research Institute of Epidemiology, 3A Novogireevskaya Street, Moscow, 111123, Russian Federation
| | - Dmitry Zarifyan
- Viral Hepatitis Laboratory, Central Research Institute of Epidemiology, 3A Novogireevskaya Street, Moscow, 111123, Russian Federation
| | - Irina Goptar
- Viral Hepatitis Laboratory, Central Research Institute of Epidemiology, 3A Novogireevskaya Street, Moscow, 111123, Russian Federation
- Izmerov Research Institute of Occupational Health, Moscow, 105275, Russian Federation
| | - Vladimir Chulanov
- Viral Hepatitis Laboratory, Central Research Institute of Epidemiology, 3A Novogireevskaya Street, Moscow, 111123, Russian Federation
- Sechenov University, Moscow, 119146, Russian Federation
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Purin-6-one and pyrrolo[2,3-d]pyrimidin-4-one derivatives as potentiating agents of doxorubicin cytotoxicity. Future Med Chem 2018; 10:2029-2038. [PMID: 30067076 DOI: 10.4155/fmc-2018-0086] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
AIM DNA damage response plays an eminent role in patients' response to conventional chemotherapy and radiotherapy. Its inhibition is of great interest as it can overcome cancer cell resistance and reduce the effective doses of DNA damaging agents. Results & methodology: We have focused our research on phosphatidylinositol 3-kinase-related kinases and prepared 35 novel compounds through a scaffold hopping approach. The newly synthesized inhibitors were tested on a panel of nine cancer and one healthy cell lines alone and in combination with appropriate doses of doxorubicin. CONCLUSION Five novel compounds 4f, 10b, 15g, 7e and 15f in combination with doxorubicin showed significant antiproliferative effect on seven cancer cell lines while not affecting the cell growth alone.
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George VC, Ansari SA, Chelakkot VS, Chelakkot AL, Chelakkot C, Menon V, Ramadan W, Ethiraj KR, El-Awady R, Mantso T, Mitsiogianni M, Panagiotidis MI, Dellaire G, Vasantha Rupasinghe HP. DNA-dependent protein kinase: Epigenetic alterations and the role in genomic stability of cancer. MUTATION RESEARCH-REVIEWS IN MUTATION RESEARCH 2018; 780:92-105. [PMID: 31395353 DOI: 10.1016/j.mrrev.2018.06.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/22/2018] [Accepted: 06/13/2018] [Indexed: 12/28/2022]
Abstract
DNA-dependent protein kinase (DNA-PK), a member of phosphatidylinositol-kinase family, is a key protein in mammalian DNA double-strand break (DSB) repair that helps to maintain genomic integrity. DNA-PK also plays a central role in immune cell development and protects telomerase during cellular aging. Epigenetic deregulation due to endogenous and exogenous factors may affect the normal function of DNA-PK, which in turn could impair DNA repair and contribute to genomic instability. Recent studies implicate a role for epigenetics in the regulation of DNA-PK expression in normal and cancer cells, which may impact cancer progression and metastasis as well as provide opportunities for treatment and use of DNA-PK as a novel cancer biomarker. In addition, several small molecules and biological agents have been recently identified that can inhibit DNA-PK function or expression, and thus hold promise for cancer treatments. This review discusses the impact of epigenetic alterations and the expression of DNA-PK in relation to the DNA repair mechanisms with a focus on its differential levels in normal and cancer cells.
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Affiliation(s)
- Vazhappilly Cijo George
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Shabbir Ahmed Ansari
- Department of Cellular and Molecular Biology, The University of Texas Health Science Center at Tyler, Tyler, TX, United States
| | - Vipin Shankar Chelakkot
- Division of BioMedical Sciences, Faculty of Medicine, Memorial University of Newfoundland, St. John's, Newfoundland, Canada
| | | | - Chaithanya Chelakkot
- Division of Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang, Republic of Korea
| | - Varsha Menon
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates
| | - Wafaa Ramadan
- Sharjah Institute for Medical Research, University of Sharjah, Sharjah, United Arab Emirates; College of Medicine, University of Sharjah, Sharjah, United Arab Emirates
| | | | - 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; Cancer Biology Department, National Cancer Institute and College of Medicine, Cairo University, Cairo, Egypt
| | - Theodora Mantso
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Department of Applied Sciences, Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Melina Mitsiogianni
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Department of Applied Sciences, Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Mihalis I Panagiotidis
- Department of Applied Sciences, Faculty of Health & Life Sciences, Northumbria University, Newcastle upon Tyne, United Kingdom
| | - Graham Dellaire
- Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada
| | - H P Vasantha Rupasinghe
- Department of Plant, Food, and Environmental Sciences, Faculty of Agriculture, Dalhousie University, Truro, NS, Canada; Department of Pathology, Faculty of Medicine, Dalhousie University, Halifax, NS, Canada.
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Yang L, Yang X, Tang Y, Zhang D, Zhu L, Wang S, Wang B, Ma T. Inhibition of DNA‑PK activity sensitizes A549 cells to X‑ray irradiation by inducing the ATM‑dependent DNA damage response. Mol Med Rep 2018; 17:7545-7552. [PMID: 29620203 PMCID: PMC5983948 DOI: 10.3892/mmr.2018.8828] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Accepted: 02/16/2018] [Indexed: 12/12/2022] Open
Abstract
Non‑small cell lung cancer (NSCLC) is radioresistant to X‑rays due to powerful cellular DNA damage repair mechanisms. DNA‑dependent protein kinase (DNA‑PK) is a key enzyme involved in DNA damage repair and the phenomenon and molecular mechanism of NSCLC radionsensitivity were investigated following inhibition of DNA‑PK activity. In the present study A549 cells were treated with the DNA‑PK inhibitor NU7026 and/or siRNA directed against ataxia telangiectasia mutated (ATM), followed by exposure to 4 Gy X‑ray irradiation. Radiosensitivity, DNA damage, apoptosis and protein expression were measured by colony formation assay, γH2AX foci immunofluorescence, Annexin V/PI staining and western blotting, respectively. A Balb/c‑nu/nu xenograft mouse model was established by subcutaneous injection of A549 cells and was used to examine the effect of administering NU7026 via intraperitoneal injection prior to 4 Gy X‑ray exposure. The xenograft tumors were weighed and observed by hematoxylin and eosin staining after irradiation. NU7026 treatment followed by X‑ray irradiation significantly decreased the colony formation ratio of A549 cells, and increased γH2AX foci and cell apoptosis. Furthermore, the combined treatment of NU7026 and X‑rays resulted in growth inhibition and cell apoptosis in A549 xenograft tumors. Consequently, apoptosis regulators full‑length transactivating (TA) p73 and an N‑terminally truncated (DN) p73 were upregulated and downregulated respectively, leading to activation of glucosyltransferases and Rab‑like GTPase activators and myotubularins domain‑containing 4 (GRAMD4) protein to reduce the Bcl‑2/Bax protein ratio. In addition, ATM siRNA efficiently prevented γH2AX foci formation, and enhanced NU7026‑induced inhibition of survival and promoted apoptosis. In conclusion, inhibition of DNA‑PK activity increased the radiosensitivity of A549 cells to X‑ray irradiation. NU7026 treatment activated the ATM‑dependent DNA damage response and induced p73 apoptosis pathway. DNA‑PK inhibitor may be an effective constituent of radiosensitization products. DNA damage repair pathway could be a potential target for radiosensitization.
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Affiliation(s)
- Lina Yang
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
| | - Xinrui Yang
- Center for Therapeutic Research of Hepatocarcinoma, Beijing 302 Hospital, Beijing 100039, P.R. China
| | - Yiwei Tang
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
| | - Defu Zhang
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
| | - Lijie Zhu
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
| | - Shengnan Wang
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
| | - Bo Wang
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
| | - Tao Ma
- College of Food Science and Technology, Bohai University, Jinzhou, Liaoning 121013, P.R. China
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Mihailidou C, Karamouzis MV, Schizas D, Papavassiliou AG. Co-targeting c-Met and DNA double-strand breaks (DSBs): Therapeutic strategies in BRCA-mutated gastric carcinomas. Biochimie 2017; 142:135-143. [DOI: 10.1016/j.biochi.2017.09.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2017] [Accepted: 09/04/2017] [Indexed: 02/06/2023]
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9
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Durisova K, Salovska B, Pejchal J, Tichy A. Chemical inhibition of DNA repair kinases as a promising tool in oncology. Biomed Pap Med Fac Univ Palacky Olomouc Czech Repub 2016; 160:11-9. [DOI: 10.5507/bp.2015.046] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2014] [Accepted: 09/10/2015] [Indexed: 11/23/2022] Open
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10
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Dolman MEM, van der Ploeg I, Koster J, Bate-Eya LT, Versteeg R, Caron HN, Molenaar JJ. DNA-Dependent Protein Kinase As Molecular Target for Radiosensitization of Neuroblastoma Cells. PLoS One 2015; 10:e0145744. [PMID: 26716839 PMCID: PMC4696738 DOI: 10.1371/journal.pone.0145744] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 12/08/2015] [Indexed: 11/18/2022] Open
Abstract
Tumor cells might resist therapy with ionizing radiation (IR) by non-homologous end-joining (NHEJ) of IR-induced double-strand breaks. One of the key players in NHEJ is DNA-dependent protein kinase (DNA-PK). The catalytic subunit of DNA-PK, i.e. DNA-PKcs, can be inhibited with the small-molecule inhibitor NU7026. In the current study, the in vitro potential of NU7026 to radiosensitize neuroblastoma cells was investigated. DNA-PKcs is encoded by the PRKDC (protein kinase, DNA-activated, catalytic polypeptide) gene. We showed that PRKDC levels were enhanced in neuroblastoma patients and correlated with a more advanced tumor stage and poor prognosis, making DNA-PKcs an interesting target for radiosensitization of neuroblastoma tumors. Optimal dose finding for combination treatment with NU7026 and IR was performed using NGP cells. One hour pre-treatment with 10 μM NU7026 synergistically sensitized NGP cells to 0.63 Gy IR. Radiosensitizing effects of NU7026 increased in time, with maximum effects observed from 96 h after IR-exposure on. Combined treatment of NGP cells with 10 μM NU7026 and 0.63 Gy IR resulted in apoptosis, while no apoptotic response was observed for either of the therapies alone. Inhibition of IR-induced DNA-PK activation by NU7026 confirmed the capability of NGP cells to, at least partially, resist IR by NHEJ. NU7026 also synergistically radiosensitized other neuroblastoma cell lines, while no synergistic effect was observed for low DNA-PKcs-expressing non-cancerous fibroblasts. Results obtained for NU7026 were confirmed by PRKDC knockdown in NGP cells. Taken together, the current study shows that DNA-PKcs is a promising target for neuroblastoma radiosensitization.
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Affiliation(s)
- M. Emmy M. Dolman
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
- * E-mail:
| | - Ida van der Ploeg
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Jan Koster
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Laurel Tabe Bate-Eya
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Rogier Versteeg
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Huib N. Caron
- Department of Pediatric Oncology, Emma Kinderziekenhuis, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Jan J. Molenaar
- Department of Oncogenomics, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
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DNA Damage Signalling and Repair Inhibitors: The Long-Sought-After Achilles' Heel of Cancer. Biomolecules 2015; 5:3204-59. [PMID: 26610585 PMCID: PMC4693276 DOI: 10.3390/biom5043204] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Accepted: 11/09/2015] [Indexed: 12/16/2022] Open
Abstract
For decades, radiotherapy and chemotherapy were the two only approaches exploiting DNA repair processes to fight against cancer. Nowadays, cancer therapeutics can be a major challenge when it comes to seeking personalized targeted medicine that is both effective and selective to the malignancy. Over the last decade, the discovery of new targeted therapies against DNA damage signalling and repair has offered the possibility of therapeutic improvements in oncology. In this review, we summarize the current knowledge of DNA damage signalling and repair inhibitors, their molecular and cellular effects, and future therapeutic use.
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12
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Enhancement of silencing DNA polymerase β on the radiotherapeutic sensitivity of human esophageal carcinoma cell lines. Tumour Biol 2014; 35:10067-74. [PMID: 25015190 DOI: 10.1007/s13277-014-2308-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 07/03/2014] [Indexed: 10/25/2022] Open
Abstract
Human DNA polymerase β (DNA polymeraseβ (polβ)) is a small monomeric protein which is essential for short-patch base excision repair (BER). It plays an important role in regulating the radiation sensitivity of tumor cells in the course of tumor radiation therapy. In this study, qRT-PCR and Western blot assays were used to quantify polβ expression levels in esophageal carcinoma (EC) cells that were transfected with polβ small interfering RNA (siRNA). Cell counting Kit-8 (CCK-8), flow cytometry, and Hoechst/PI stain assays were conducted to evaluate the effects of silencing polβ on the radiotherapeutic sensitivity of EC cells. We found that the expression levels of polβ in EC cells were significantly decreased after transfection with polβ siRNA. Then, we found that polβ silencing increased the sensitivity of EC cells to radiation therapy. In conclusion, our study paves the way for a better understanding of the mechanism of the polβ gene in DNA repair, and we propose that RNA interference technology will have important applications in gene therapy of EC and other cancers in the future.
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