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Varadhan V, Manikandan MS, Nagarajan A, Palaniyandi T, Ravi M, Sankareswaran SK, Baskar G, Wahab MRA, Surendran H. Ataxia-Telangiectasia Mutated (ATM) gene signaling pathways in human cancers and their therapeutic implications. Pathol Res Pract 2024; 260:155447. [PMID: 38981349 DOI: 10.1016/j.prp.2024.155447] [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] [Received: 06/04/2024] [Revised: 06/27/2024] [Accepted: 06/28/2024] [Indexed: 07/11/2024]
Abstract
Cancer is a multifaceted disease driven by abnormal cell growth and poses a significant global health threat. The multifactorial causes, differences in individual susceptibility to therapeutic drugs, and induced drug resistance pose major challenges in addressing cancers effectively. One of the most important aspects in making cancers highly heterogeneous in their physiology lies in the genes involved and the changes occurring to some of these genes in malignant conditions. The Genetic factors have been implicated in the oncogenesis, progression, responses to treatment, and metastasis. One such gene that plays a key role in human cancers is the mutated form of the Ataxia-telangiectasia gene (ATM). ATM gene located on chromosome 11q23, plays a vital role in maintaining genomic stability. Understanding the genetic basis of A-T is crucial for diagnosis, management, and treatment. Breast cancer, lung cancer, prostate cancer, and gastric cancer exhibit varying relationships with the ATM gene and influence their pathways. Targeting the ATM pathway proves promising for enhancing treatment effectiveness, especially in conjunction with DNA damage response pathways. Analyzing the therapeutic consequences of ATM mutations, especially in these cancer types facilitates the approaches for early detection, intervention, development of personalized treatment approaches, and improved patient outcomes. This review emphasizes the role of the ATM gene in various cancers, highlighting its impact on DNA repair pathways and therapeutic responses.
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Affiliation(s)
- Varsha Varadhan
- Department of Biotechnology, Dr. M.G.R Educational and Research Institute, Chennai 600095, India
| | - Monica Shri Manikandan
- Department of Biotechnology, Dr. M.G.R Educational and Research Institute, Chennai 600095, India
| | - Akshaya Nagarajan
- Department of Biotechnology, Dr. M.G.R Educational and Research Institute, Chennai 600095, India
| | - Thirunavukkarasu Palaniyandi
- Department of Biotechnology, Dr. M.G.R Educational and Research Institute, Chennai 600095, India; Department of Anatomy, Biomedical Research Unit and Laboratory Animal Centre, Saveetha Dental College and Hospital, Saveetha Institute of Medical and Technical Science, Saveetha University, Chennai, Tamil Nadu, India.
| | - Maddaly Ravi
- Department of Human Genetics, Sri Ramachandra Institute of Higher Education and Research, Chennai 600116, Tamil Nadu, India
| | - Senthil Kumar Sankareswaran
- Department of Biotechnology, Vel Tech Rangarajan Dr. Sagunthala R&D Institute of Science and Technology, Avadi, Chennai, Tamil Nadu, India
| | - Gomathy Baskar
- Department of Biotechnology, Dr. M.G.R Educational and Research Institute, Chennai 600095, India
| | | | - Hemapreethi Surendran
- Department of Biotechnology, Dr. M.G.R Educational and Research Institute, Chennai 600095, India
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Tomiyoshi G, Nakamura R, Shinmen N, Yoshida Y, Mine S, Machida T, Iwase K, Iwadate Y, Hiwasa T, Kuroda H. GADD34 activates p53 and may have utility as a marker of atherosclerosis. Front Med (Lausanne) 2023; 10:1128921. [PMID: 37228401 PMCID: PMC10203227 DOI: 10.3389/fmed.2023.1128921] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Accepted: 04/11/2023] [Indexed: 05/27/2023] Open
Abstract
We previously identified growth arrest and DNA-damage-inducible gene 34 (GADD34) as a marker of ischemic stroke. In the present study, serum levels of anti-GADD34 antibodies were found to be significantly higher in patients with acute ischemic stroke or chronic kidney disease compared to healthy donors. We then examined the biological function of GADD34 by transfection into U2OS human osteosarcoma and U87 human glioblastoma cells. Knockdown of GADD34 by siRNA resulted in enhanced cell proliferation, which was reversed by co-knockdown of MDM2. Luciferase reporter assays revealed that the transactivation ability of p53 enhanced by genotoxic anticancer drugs such as camptothecin and etoposide was further potentiated by enforced expression of GADD34 but attenuated by co-transfection with p53 shRNA expression plasmids. Western blotting demonstrated increased p53 protein levels after treatment with camptothecin, which was also potentiated by GADD34 but suppressed by GADD34 siRNA, ATM siRNA, and ATM inhibitor wortmannin. GADD34 levels also increased in response to treatment with camptothecin or adriamycin, and this increase was attenuated by MDM2 siRNA. Immunoprecipitation with anti-GADD34 antibody followed by Western blotting with anti-MDM2 antibodies indicated ubiquitination of GADD34 is mediated by MDM2. Accordingly, GADD34 may function as a ubiquitination decoy to reduce p53 ubiquitination and increase p53 protein levels. Increased neuronal cell death due to activation of p53 by GADD34 may account for the elevated serum levels of anti-GADD34 antibodies observed in patients with acute ischemic stroke.
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Affiliation(s)
- Go Tomiyoshi
- Medical Project Division, Research Development Center, Fujikura Kasei Co., Saitama, Japan
- Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Rika Nakamura
- Medical Project Division, Research Development Center, Fujikura Kasei Co., Saitama, Japan
- Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Natsuko Shinmen
- Medical Project Division, Research Development Center, Fujikura Kasei Co., Saitama, Japan
- Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yoichi Yoshida
- Department of Neurological Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Seiichiro Mine
- Department of Neurological Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan
- Department of Neurological Surgery, Chiba Prefectural Sawara Hospital, Chiba, Japan
- Department of Neurosurgery, Chiba Cerebral and Cardiovascular Center, Chiba, Japan
| | - Toshio Machida
- Department of Neurological Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan
- Department of Neurosurgery, Chiba Cerebral and Cardiovascular Center, Chiba, Japan
- Department of Neurosurgery, Eastern Chiba Medical Center, Chiba, Japan
| | - Katsuro Iwase
- Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Yasuo Iwadate
- Department of Neurological Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Takaki Hiwasa
- Department of Biochemistry and Genetics, Graduate School of Medicine, Chiba University, Chiba, Japan
- Department of Neurological Surgery, Graduate School of Medicine, Chiba University, Chiba, Japan
| | - Hideyuki Kuroda
- Medical Project Division, Research Development Center, Fujikura Kasei Co., Saitama, Japan
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A Triphenylphosphonium-Functionalized Delivery System for an ATM Kinase Inhibitor That Ameliorates Doxorubicin Resistance in Breast Carcinoma Mammospheres. Cancers (Basel) 2023; 15:cancers15051474. [PMID: 36900267 PMCID: PMC10000448 DOI: 10.3390/cancers15051474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2022] [Revised: 02/20/2023] [Accepted: 02/23/2023] [Indexed: 03/02/2023] Open
Abstract
The enzyme ataxia-telangiectasia mutated (ATM) kinase is a pluripotent signaling mediator which activates cellular responses to genotoxic and metabolic stress. It has been shown that ATM enables the growth of mammalian adenocarcinoma stem cells, and therefore the potential benefits in cancer chemotherapy of a number of ATM inhibitors, such as KU-55933 (KU), are currently being investigated. We assayed the effects of utilizing a triphenylphosphonium-functionalized nanocarrier delivery system for KU on breast cancer cells grown either as a monolayer or in three-dimensional mammospheres. We observed that the encapsulated KU was effective against chemotherapy-resistant mammospheres of breast cancer cells, while having comparably lower cytotoxicity against adherent cells grown as monolayers. We also noted that the encapsulated KU sensitized the mammospheres to the anthracycline drug doxorubicin significantly, while having only a weak effect on adherent breast cancer cells. Our results suggest that triphenylphosphonium-functionalized drug delivery systems that contain encapsulated KU, or compounds with a similar impact, are a useful addition to chemotherapeutic treatment schemes that target proliferating cancers.
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Chloroquine-Induced DNA Damage Synergizes with Nonhomologous End Joining Inhibition to Cause Ovarian Cancer Cell Cytotoxicity. Int J Mol Sci 2022; 23:ijms23147518. [PMID: 35886866 PMCID: PMC9323666 DOI: 10.3390/ijms23147518] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 06/30/2022] [Accepted: 07/05/2022] [Indexed: 12/04/2022] Open
Abstract
Ovarian cancer (OC) is the most lethal gynecological malignancy; therefore, more effective treatments are urgently needed. We recently reported that chloroquine (CQ) increased reactive oxygen species (ROS) in OC cell lines (OCCLs), causing DNA double-strand breaks (DSBs). Here, we analyzed whether these lesions are repaired by nonhomologous end joining (NHEJ), one of the main pathways involved in DSB repair, and if the combination of CQ with NHEJ inhibitors (NHEJi) could be effective against OC. We found that NHEJ inhibition increased the persistence of γH2AX foci after CQ-induced DNA damage, revealing an essential role of this pathway in the repair of the lesions. NHEJi decreased the proliferation of OCCLs and a strong in vitro synergistic effect on apoptosis induction was observed when combined with CQ. This effect was largely abolished by the antioxidant N-Acetyl-L-cysteine, revealing the critical role of ROS and DSB generation in CQ/NHEJi-induced lethality. We also found that the NHEJ efficiency in OCCLs was not affected by treatment with Panobinostat, a pan-histone deacetylase inhibitor that also synergizes with CQ in OCCLs by impairing homologous recombination. Accordingly, the triple combination of CQ-NHEJi-Panobinostat exerted a stronger in vitro synergistic effect. Altogether, our data suggest that the combination of these drugs could represent new therapeutic strategies against OC.
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Lee JH, Jeon B, Park M, Ha J, Kim SJ, Son MK, Wang S, Lee JH, Jeong YK. Synergistic radiosensitizing effect of BR101801, a specific DNA-dependent protein kinase inhibitor, in various human solid cancer cells and xenografts. Am J Cancer Res 2021; 11:5440-5451. [PMID: 34873471 PMCID: PMC8640799] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 10/07/2021] [Indexed: 06/13/2023] Open
Abstract
DNA-dependent protein kinase (DNA-PK), an essential component of the non-homologous end-joining (NHEJ) repair pathway, plays an important role in DNA damage repair (DDR). Therefore, DNA-PK inhibition is a promising approach for overcoming radiotherapy or chemotherapy resistance in cancers. In this study, we demonstrated that BR101801, a potent DNA-PK inhibitor, acted as an effective radiosensitizer in various human solid cancer cells and an in vivo xenograft model. Overall, BR101801 strongly elevated ionizing radiation (IR)-induced genomic instability via induction of cell cycle G2/M arrest, autophagic cell death, and impairment of DDR pathway in human solid cancer cells. Interestingly, BR101801 inhibited not only phosphorylation of DNA-PK catalytic subunit in NHEJ factors but also BRCA2 protein level in homologous recombination (HR) factors. In addition, combination BR101801 and IR suppressed tumor growth compared with IR alone by reducing phosphorylation of DNA-PK in human solid cancer xenografts. Our findings suggested that BR101801 is a selective DNA-PK inhibitor with a synergistic radiosensitizing effect in human solid cancers, providing evidence for clinical applications.
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Affiliation(s)
- Jae Hee Lee
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical SciencesSeoul 01812, Republic of Korea
| | - Byeongwook Jeon
- Boryung Pharmaceutical, R&D CenterAnsan 15425, Republic of Korea
| | - Mijeong Park
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical SciencesSeoul 01812, Republic of Korea
| | - Jimin Ha
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical SciencesSeoul 01812, Republic of Korea
| | - Soo Jung Kim
- Boryung Pharmaceutical, R&D CenterAnsan 15425, Republic of Korea
| | - Mi Kwon Son
- Boryung Pharmaceutical, R&D CenterAnsan 15425, Republic of Korea
| | - Seungho Wang
- Boryung Pharmaceutical, R&D CenterAnsan 15425, Republic of Korea
| | - Joo Han Lee
- Boryung Pharmaceutical, R&D CenterAnsan 15425, Republic of Korea
| | - Youn Kyoung Jeong
- Radiological and Medical Support Center, Korea Institute of Radiological and Medical SciencesSeoul 01812, Republic of Korea
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Lee KJ, Mann E, Wright G, Piett CG, Nagel ZD, Gassman NR. Exploiting DNA repair defects in triple negative breast cancer to improve cell killing. Ther Adv Med Oncol 2020; 12:1758835920958354. [PMID: 32994807 PMCID: PMC7502856 DOI: 10.1177/1758835920958354] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2020] [Accepted: 08/19/2020] [Indexed: 12/13/2022] Open
Abstract
Background: The lack of molecular targets for triple negative breast cancer (TNBC) has limited treatment options and reduced survivorship. Identifying new molecular targets may help improve patient survival and decrease recurrence and metastasis. As DNA repair defects are prevalent in breast cancer, we evaluated the expression and repair capacities of DNA repair proteins in preclinical models. Methods: DNA repair capacity was analyzed in four TNBC cell lines, MDA-MB-157 (MDA-157), MDA-MB-231 (MDA-231), MDA-MB-468 (MDA-468), and HCC1806, using fluorescence multiplex host cell reactivation (FM-HCR) assays. Expression of DNA repair genes was analyzed with RNA-seq, and protein expression was evaluated with immunoblot. Responses to the combination of DNA damage response inhibitors and primary chemotherapy drugs doxorubicin or carboplatin were evaluated in the cell lines. Results: Defects in base excision and nucleotide excision repair were observed in preclinical TNBC models. Gene expression analysis showed a limited correlation between these defects. Loss in protein expression was a better indicator of these DNA repair defects. Over-expression of PARP1, XRCC1, RPA, DDB1, and ERCC1 was observed in TNBC preclinical models, and likely contributed to altered sensitivity to chemotherapy and DNA damage response (DDR) inhibitors. Improved cell killing was achieved when primary therapy was combined with DDR inhibitors for ATM, ATR, or CHK1. Conclusion: Base excision and nucleotide excision repair pathways may offer new molecular targets for TNBC. The functional status of DNA repair pathways should be considered when evaluating new therapies and may improve the targeting for primary and combination therapies with DDR inhibitors.
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Affiliation(s)
- Kevin J Lee
- College of Medicine, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - Elise Mann
- College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Griffin Wright
- College of Medicine, Mitchell Cancer Institute, University of South Alabama, Mobile, AL, USA
| | - Cortt G Piett
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Zachary D Nagel
- Harvard T.H. Chan School of Public Health, Harvard University, Boston, MA, USA
| | - Natalie R Gassman
- Mitchell Cancer Institute, University of South Alabama, 1660 Springhill Avenue, Mobile, AL 36607, USA
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Nandy D, Rajam SM, Dutta D. A three layered histone epigenetics in breast cancer metastasis. Cell Biosci 2020; 10:52. [PMID: 32257110 PMCID: PMC7106732 DOI: 10.1186/s13578-020-00415-1] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 03/26/2020] [Indexed: 12/13/2022] Open
Abstract
Thanks to the advancement in science and technology and a significant number of cancer research programs being carried out throughout the world, the prevention, prognosis and treatment of breast cancer are improving with a positive and steady pace. However, a stern thoughtful attention is required for the metastatic breast cancer cases—the deadliest of all types of breast cancer, with a character of relapse even when treated. In an effort to explore the less travelled avenues, we summarize here studies underlying the aspects of histone epigenetics in breast cancer metastasis. Authoritative reviews on breast cancer epigenetics are already available; however, there is an urgent need to focus on the epigenetics involved in metastatic character of this cancer. Here we put forward a comprehensive review on how different layers of histone epigenetics comprising of histone chaperones, histone variants and histone modifications interplay to create breast cancer metastasis landscape. Finally, we propose a hypothesis of integrating histone-epigenetic factors as biomarkers that encompass different breast cancer subtypes and hence could be exploited as a target of larger population.
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Affiliation(s)
- Debparna Nandy
- Regenerative Biology Program, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Poojappura, Thiruvananthapuram, Kerala 695014 India
| | - Sruthy Manuraj Rajam
- Regenerative Biology Program, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Poojappura, Thiruvananthapuram, Kerala 695014 India
| | - Debasree Dutta
- Regenerative Biology Program, Rajiv Gandhi Centre for Biotechnology, Thycaud PO, Poojappura, Thiruvananthapuram, Kerala 695014 India
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8
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Targeting the DNA Damage Response for Radiosensitization. CANCER DRUG DISCOVERY AND DEVELOPMENT 2020. [DOI: 10.1007/978-3-030-49701-9_9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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9
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Radiosensitizing activity of novel small molecule BRCA1 and DNA-PK inhibitors in lung and colon carcinoma. JOURNAL OF RADIATION RESEARCH AND APPLIED SCIENCES 2019. [DOI: 10.1016/j.jrras.2017.04.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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10
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Miles MA, Hawkins CJ. Mutagenic assessment of chemotherapy and Smac mimetic drugs in cells with defective DNA damage response pathways. Sci Rep 2018; 8:14421. [PMID: 30258062 PMCID: PMC6158240 DOI: 10.1038/s41598-018-32517-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Accepted: 09/05/2018] [Indexed: 12/15/2022] Open
Abstract
DNA damaging therapies can spur the formation of therapy-related cancers, due to mis-repair of lesions they create in non-cancerous cells. This risk may be amplified in patients with impaired DNA damage responses. We disabled key DNA damage response pathways using genetic and pharmacological approaches, and assessed the impact of these deficiencies on the mutagenicity of chemotherapy drugs or the "Smac mimetic" GDC-0152, which kills tumor cells by targeting XIAP, cIAP1 and 2. Doxorubicin and cisplatin provoked mutations in more surviving cells deficient in ATM, p53 or the homologous recombination effector RAD51 than in wild type cells, but suppressing non-homologous end joining (NHEJ) by disabling DNA-PKcs prevented chemotherapy-induced mutagenesis. Vincristine-induced mutagenesis required p53 and DNA-PKcs but was not affected by ATM status, consistent with it provoking ATM-independent p53-mediated activation of caspases and CAD, which creates DNA lesions in surviving cells that could be mis-repaired by NHEJ. Encouragingly, GDC-0152 failed to stimulate mutations in cells with proficient or defective DNA damage response pathways. This study highlights the elevated oncogenic risk associated with treating DNA repair-deficient patients with genotoxic anti-cancer therapies, and suggests a potential advantage for Smac mimetic drugs over traditional therapies: a reduced risk of therapy-related cancers.
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Affiliation(s)
- Mark A Miles
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia
| | - Christine J Hawkins
- Department of Biochemistry and Genetics, La Trobe Institute for Molecular Science, La Trobe University, Victoria, Australia.
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Targeting Oxidatively Induced DNA Damage Response in Cancer: Opportunities for Novel Cancer Therapies. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2018; 2018:2389523. [PMID: 29770165 PMCID: PMC5892224 DOI: 10.1155/2018/2389523] [Citation(s) in RCA: 75] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 01/22/2018] [Indexed: 12/17/2022]
Abstract
Cancer is a death cause in economically developed countries that results growing also in developing countries. Improved outcome through targeted interventions faces the scarce selectivity of the therapies and the development of resistance to them that compromise the therapeutic effects. Genomic instability is a typical cancer hallmark due to DNA damage by genetic mutations, reactive oxygen and nitrogen species, ionizing radiation, and chemotherapeutic agents. DNA lesions can induce and/or support various diseases, including cancer. The DNA damage response (DDR) is a crucial signaling-transduction network that promotes cell cycle arrest or cell death to repair DNA lesions. DDR dysregulation favors tumor growth as downregulated or defective DDR generates genomic instability, while upregulated DDR may confer treatment resistance. Redox homeostasis deeply and capillary affects DDR as ROS activate/inhibit proteins and enzymes integral to DDR both in healthy and cancer cells, although by different routes. DDR regulation through modulating ROS homeostasis is under investigation as anticancer opportunity, also in combination with other treatments since ROS affect DDR differently in the patients during cancer development and treatment. Here, we highlight ROS-sensitive proteins whose regulation in oxidatively induced DDR might allow for selective strategies against cancer that are better tailored to the patients.
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Timme CR, Rath BH, O'Neill JW, Camphausen K, Tofilon PJ. The DNA-PK Inhibitor VX-984 Enhances the Radiosensitivity of Glioblastoma Cells Grown In Vitro and as Orthotopic Xenografts. Mol Cancer Ther 2018; 17:1207-1216. [PMID: 29549168 DOI: 10.1158/1535-7163.mct-17-1267] [Citation(s) in RCA: 81] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 02/05/2018] [Accepted: 03/12/2018] [Indexed: 11/16/2022]
Abstract
Radiotherapy is a primary treatment modality for glioblastomas (GBM). Because DNA-PKcs is a critical factor in the repair of radiation-induced double strand breaks (DSB), this study evaluated the potential of VX-984, a new DNA-PKcs inhibitor, to enhance the radiosensitivity of GBM cells. Treatment of the established GBM cell line U251 and the GBM stem-like cell (GSC) line NSC11 with VX-984 under in vitro conditions resulted in a concentration-dependent inhibition of radiation-induced DNA-PKcs phosphorylation. In a similar concentration-dependent manner, VX-984 treatment enhanced the radiosensitivity of each GBM cell line as defined by clonogenic analysis. As determined by γH2AX expression and neutral comet analyses, VX-984 inhibited the repair of radiation-induced DNA double-strand break in U251 and NSC11 GBM cells, suggesting that the VX-984-induced radiosensitization is mediated by an inhibition of DNA repair. Extending these results to an in vivo model, treatment of mice with VX-984 inhibited radiation-induced DNA-PKcs phosphorylation in orthotopic brain tumor xenografts, indicating that this compound crosses the blood-brain tumor barrier at sufficient concentrations. For mice bearing U251 or NSC11 brain tumors, VX-984 treatment alone had no significant effect on overall survival; radiation alone increased survival. The survival of mice receiving the combination protocol was significantly increased as compared with control and as compared with radiation alone. These results indicate that VX-984 enhances the radiosensitivity of brain tumor xenografts and suggest that it may be of benefit in the therapeutic management of GBM. Mol Cancer Ther; 17(6); 1207-16. ©2018 AACR.
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Affiliation(s)
- Cindy R Timme
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Barbara H Rath
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - John W O'Neill
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Kevin Camphausen
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland
| | - Philip J Tofilon
- Radiation Oncology Branch, National Cancer Institute, Bethesda, Maryland.
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Targeting DNA double strand break repair with hyperthermia and DNA-PKcs inhibition to enhance the effect of radiation treatment. Oncotarget 2018; 7:65504-65513. [PMID: 27602767 PMCID: PMC5323171 DOI: 10.18632/oncotarget.11798] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Accepted: 08/24/2016] [Indexed: 12/28/2022] Open
Abstract
Radiotherapy is based on the induction of lethal DNA damage, primarily DNA double-strand breaks (DSB). Efficient DSB repair via Non-Homologous End Joining or Homologous Recombination can therefore undermine the efficacy of radiotherapy. By suppressing DNA-DSB repair with hyperthermia (HT) and DNA-PKcs inhibitor NU7441 (DNA-PKcsi), we aim to enhance the effect of radiation. The sensitizing effect of HT for 1 hour at 42°C and DNA-PKcsi [1 μM] to radiation treatment was investigated in cervical and breast cancer cells, primary breast cancer sphere cells (BCSCs) enriched for cancer stem cells, and in an in vivo human tumor model. A significant radio-enhancement effect was observed for all cell types when DNA-PKcsi and HT were applied separately, and when both were combined, HT and DNA-PKcsi enhanced radio-sensitivity to an even greater extent. Strikingly, combined treatment resulted in significantly lower survival rates, 2 to 2.5 fold increase in apoptosis, more residual DNA-DSB 6 h post treatment and a G2-phase arrest. In addition, tumor growth analysis in vivo showed significant reduction in tumor growth and elevated caspase-3 activity when radiation was combined with HT and DNA-PKcsi compared to radiation alone. Importantly, no toxic side effects of HT or DNA-PKcsi were found. In conclusion, inhibiting DNA-DSB repair using HT and DNA-PKcsi before radiotherapy leads to enhanced cytotoxicity in cancer cells. This effect was even noticed in the more radio-resistant BCSCs, which are clearly sensitized by combined treatment. Therefore, the addition of HT and DNA-PKcsi to conventional radiotherapy is promising and might contribute to more efficient tumor control and patient outcome.
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Nowacka-Zawisza M, Wiśnik E. DNA methylation and histone modifications as epigenetic regulation in prostate cancer (Review). Oncol Rep 2017; 38:2587-2596. [PMID: 29048620 DOI: 10.3892/or.2017.5972] [Citation(s) in RCA: 77] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2017] [Accepted: 07/24/2017] [Indexed: 11/06/2022] Open
Abstract
Prostate cancer is the second most commonly diagnosed cancer in men in Poland after lung cancer and the third leading cause of cancer-related mortality after lung and colon cancer. The etiology of most cases of prostate cancer are not fully known, and therefore it is essential to search for the molecular basis of prostate cancer and markers for the early diagnosis of this type of cancer. Epigenetics deals with changes in gene expression that are not determined by changes in the DNA sequence. Epigenetic changes refer to changes in the structure of DNA, which are the result of DNA modification after replication and/or post-translational modification of proteins associated with DNA. In contrast to mutations, epigenetic changes are reversible and occur very rapidly. The major epigenetic mechanisms include DNA methylation, modification of histone proteins, chemical modification and chromatin remodeling changes in gene expression caused by microRNAs (miRNAs). Epigenetic changes play an important role in malignant transformation and can be specific to types of cancers including prostate cancer.
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Affiliation(s)
- Maria Nowacka-Zawisza
- Department of Cytobiochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
| | - Ewelina Wiśnik
- Department of Cytobiochemistry, Faculty of Biology and Environmental Protection, University of Lodz, 90-236 Lodz, Poland
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Alikarami F, Safa M, Faranoush M, Hayat P, Kazemi A. Inhibition of DNA-PK enhances chemosensitivity of B-cell precursor acute lymphoblastic leukemia cells to doxorubicin. Biomed Pharmacother 2017; 94:1077-1093. [PMID: 28821159 DOI: 10.1016/j.biopha.2017.08.022] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2017] [Revised: 07/09/2017] [Accepted: 08/04/2017] [Indexed: 12/13/2022] Open
Abstract
DNA damage repair pathways greatly affect the response to genotoxic drugs in cancer cells, so inhibition of such pathways could be a potentially useful strategy to enhance chemosensitivity. DNA-dependent protein kinase (DNA-PK) plays a crucial role in the repair of DNA double-strand breaks (DSBs) that are probably one of the most detrimental types of DNA damage. It has been shown that DNA-PK is highly expressed in B-cell precursor acute lymphoblastic leukemia (BCP-ALL) cells. Less well appreciated was the effect of DNA-PK inhibition on sensitivity of BCP-ALL cells to DNA-damaging agents. Here, we show that the DNA-PK inhibitor NU7441 increased doxorubicin-induced apoptosis in BCP-ALL cell lines (NALM-6, SUP-B15), correlating with a reduction in DSB repair measured by γ-H2AX foci. NU7441 affected the cell cycle distribution and the cell cycle regulatory molecules in combination with doxorubicin treatment. Doxorubicin-induced DNA-PK phosphorylation was decreased in the presence of NU7441. Apoptosis induction by the combined treatment was associated with marked reduction of Bcl-2 and survivin and a significant increase of Bax mRNA expression levels. In conclusion, our data indicate that inhibition of DNA-PK might be an effective approach to enhance the tumor-cell-killing effects of DNA-damaging agents such as doxorubicin in BCP-ALL and may deliver novel, targeted therapy into the clinic.
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Affiliation(s)
- Fatemeh Alikarami
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
| | - Majid Safa
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran; Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran.
| | - Mohammad Faranoush
- Pediatric Growth and Development Research Center, Institute of Endocrinology and Metabolism, Iran University of Medical Sciences, Tehran, Iran
| | - Parisa Hayat
- Cellular and Molecular Research Center, Iran University of Medical Sciences, Tehran, Iran
| | - Ahmad Kazemi
- Department of Hematology and Blood Banking, Faculty of Allied Medicine, Iran University of Medical Sciences, Tehran, Iran
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Yanai M, Makino H, Ping B, Takeda K, Tanaka N, Sakamoto T, Yamaguchi K, Kodani M, Yamasaki A, Igishi T, Shimizu E. DNA-PK Inhibition by NU7441 Enhances Chemosensitivity to Topoisomerase Inhibitor in Non-Small Cell Lung Carcinoma Cells by Blocking DNA Damage Repair. Yonago Acta Med 2017; 60:9-15. [PMID: 28331416 PMCID: PMC5355839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 12/21/2016] [Indexed: 06/06/2023]
Abstract
BACKGROUND DNA double-strand breaks (DSBs) are the most cytotoxic form of DNA damage and are induced by ionizing radiation and specific chemotherapeutic agents, such as topoisomerase inhibitors. Cancer cells acquire resistance to such therapies by repairing DNA DSBs. A major pathway for the repair of DNA DSBs is non-homologous end-joining (NHEJ), which requires DNA-dependent protein kinase (DNA-PK) activity. In this study, we investigated the effect of NU7441, a synthetic small-molecule compound, as a specific inhibitor of DNA-PK on the chemosensitization of non-small cell lung carcinoma (NSCLC) A549 cells. METHODS The combined effects of chemotherapeutic agents and NU7441 were evaluated by isobologram analysis using Cell Counting Kit-8. DNA DSBs were assessed by immunofluorescence assay. Apoptosis was examined by flow cytometry using an Annexin V apoptosis kit. Activation of DNA-PK was assayed by western blotting. RESULTS The combination of NU7441 and topoisomerase inhibitors such as amrubicin and irinotecan had a synergistic effect on cell proliferation in A549 cells. NU7441 increased 53BP1 foci and apoptosis induced by topoisomerase inhibitors and decreased phospho-DNA-dependent protein kinase, catalytic subunit (pDNA-PKcs) (S2056) protein expression caused by topoisomerase inhibitors. Interestingly, mitotic inhibitors such as pacritaxel did not cause the pDNA-PKcs (S2056) protein expression and the combination of NU7441 and pacritaxel had an only additive effect. CONCLUSION NU7441 inhibited the growth of NSCLC cells and enhanced the chemosensitization to topoisomerase inhibitors by blocking DNA repair. A combination of NU7441 and topoisomerase inhibitor may be a promising treatment for NSCLC.
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Affiliation(s)
- Masaaki Yanai
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Haruhiko Makino
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Bingqiong Ping
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Kenichi Takeda
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Natsumi Tanaka
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Tomohiro Sakamoto
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Kosuke Yamaguchi
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Masahiro Kodani
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Akira Yamasaki
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Tadashi Igishi
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
| | - Eiji Shimizu
- Division of Medical Oncology and Molecular Respirology, Department of Multidisciplinary Internal Medicine, School of Medicine, Tottori University Faculty of Medicine, Yonago 683-8504, Japan
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van Oorschot B, Granata G, Di Franco S, Ten Cate R, Rodermond HM, Todaro M, Medema JP, Franken NAP. Targeting DNA double strand break repair with hyperthermia and DNA-PKcs inhibition to enhance the effect of radiation treatment. Oncotarget 2016. [PMID: 27602767 DOI: 10.1863/oncotarget.11798] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/19/2023] Open
Abstract
Radiotherapy is based on the induction of lethal DNA damage, primarily DNA double-strand breaks (DSB). Efficient DSB repair via Non-Homologous End Joining or Homologous Recombination can therefore undermine the efficacy of radiotherapy. By suppressing DNA-DSB repair with hyperthermia (HT) and DNA-PKcs inhibitor NU7441 (DNA-PKcsi), we aim to enhance the effect of radiation.The sensitizing effect of HT for 1 hour at 42°C and DNA-PKcsi [1 μM] to radiation treatment was investigated in cervical and breast cancer cells, primary breast cancer sphere cells (BCSCs) enriched for cancer stem cells, and in an in vivo human tumor model. A significant radio-enhancement effect was observed for all cell types when DNA-PKcsi and HT were applied separately, and when both were combined, HT and DNA-PKcsi enhanced radio-sensitivity to an even greater extent. Strikingly, combined treatment resulted in significantly lower survival rates, 2 to 2.5 fold increase in apoptosis, more residual DNA-DSB 6 h post treatment and a G2-phase arrest. In addition, tumor growth analysis in vivo showed significant reduction in tumor growth and elevated caspase-3 activity when radiation was combined with HT and DNA-PKcsi compared to radiation alone. Importantly, no toxic side effects of HT or DNA-PKcsi were found.In conclusion, inhibiting DNA-DSB repair using HT and DNA-PKcsi before radiotherapy leads to enhanced cytotoxicity in cancer cells. This effect was even noticed in the more radio-resistant BCSCs, which are clearly sensitized by combined treatment. Therefore, the addition of HT and DNA-PKcsi to conventional radiotherapy is promising and might contribute to more efficient tumor control and patient outcome.
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Affiliation(s)
- Bregje van Oorschot
- Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine, Department of Radiation Oncology, Academic Medical Center, Cancer Genomics Center, Amsterdam, The Netherlands
| | - Giovanna Granata
- Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine, Department of Radiation Oncology, Academic Medical Center, Cancer Genomics Center, Amsterdam, The Netherlands
| | - Simone Di Franco
- Department of Surgical, Oncological and Stomatological Sciences (DICHIRONS), Cellular and Molecular Pathophysiology Laboratory, University of Palermo, Palermo, Italy
| | - Rosemarie Ten Cate
- Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine, Department of Radiation Oncology, Academic Medical Center, Cancer Genomics Center, Amsterdam, The Netherlands
| | - Hans M Rodermond
- Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine, Department of Radiation Oncology, Academic Medical Center, Cancer Genomics Center, Amsterdam, The Netherlands
| | - Matilde Todaro
- Biomedical Department of Internal and Specialistic Medicine (DIBIMIS), University of Palermo, Palermo, Italy
| | - Jan Paul Medema
- Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine, Department of Radiation Oncology, Academic Medical Center, Cancer Genomics Center, Amsterdam, The Netherlands
| | - Nicolaas A P Franken
- Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Experimental Molecular Medicine, Department of Radiation Oncology, Academic Medical Center, Cancer Genomics Center, Amsterdam, The Netherlands
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Finzel A, Grybowski A, Strasen J, Cristiano E, Loewer A. Hyperactivation of ATM upon DNA-PKcs inhibition modulates p53 dynamics and cell fate in response to DNA damage. Mol Biol Cell 2016; 27:2360-7. [PMID: 27280387 PMCID: PMC4966978 DOI: 10.1091/mbc.e16-01-0032] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 05/31/2016] [Indexed: 01/15/2023] Open
Abstract
Time-resolved single-cell analysis and pharmacological perturbations reveal a new regulatory interplay between PI3K-like kinases in response to DNA double-strand breaks: upon loss of DNA-PKcs activity, ATM is hyperactivated and induces an amplified p53 response, which sensitizes cells for damage-induced senescence. A functional DNA damage response is essential for maintaining genome integrity in the presence of DNA double-strand breaks. It is mainly coordinated by the kinases ATM, ATR, and DNA-PKcs, which control the repair of broken DNA strands and relay the damage signal to the tumor suppressor p53 to induce cell cycle arrest, apoptosis, or senescence. Although many functions of the individual kinases have been identified, it remains unclear how they act in concert to ensure faithful processing of the damage signal. Using specific inhibitors and quantitative analysis at the single-cell level, we systematically characterize the contribution of each kinase for regulating p53 activity. Our results reveal a new regulatory interplay in which loss of DNA-PKcs function leads to hyperactivation of ATM and amplification of the p53 response, sensitizing cells for damage-induced senescence. This interplay determines the outcome of treatment regimens combining irradiation with DNA-PKcs inhibitors in a p53-dependent manner.
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Affiliation(s)
- Ana Finzel
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Andrea Grybowski
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Jette Strasen
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Elena Cristiano
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany
| | - Alexander Loewer
- Berlin Institute for Medical Systems Biology, Max Delbrück Center for Molecular Medicine, 13125 Berlin, Germany Department of Biology, Technische Universitaet Darmstadt, 64287 Darmstadt, Germany
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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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Sears CR, Cooney SA, Chin-Sinex H, Mendonca MS, Turchi JJ. DNA damage response (DDR) pathway engagement in cisplatin radiosensitization of non-small cell lung cancer. DNA Repair (Amst) 2016; 40:35-46. [PMID: 26991853 DOI: 10.1016/j.dnarep.2016.02.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 02/05/2016] [Accepted: 02/15/2016] [Indexed: 12/28/2022]
Abstract
Non-small cell lung cancers (NSCLC) are commonly treated with a platinum-based chemotherapy such as cisplatin (CDDP) in combination with ionizing radiation (IR). Although clinical trials have demonstrated that the combination of CDDP and IR appear to be synergistic in terms of therapeutic efficacy, the mechanism of synergism remains largely uncharacterized. We investigated the role of the DNA damage response (DDR) in CDDP radiosensitization using two NSCLC cell lines. Using clonogenic survival assays, we determined that the cooperative cytotoxicity of CDDP and IR treatment is sequence dependent, requiring administration of CDDP prior to IR (CDDP-IR). We identified and interrogated the unique time and agent-dependent activation of the DDR in NSCLC cells treated with cisplatin-IR combination therapy. Compared to treatment with CDDP or IR alone, CDDP-IR combination treatment led to persistence of γH2Ax foci, a marker of DNA double-strand breaks (DSB), for up to 24h after treatment. Interestingly, pharmacologic inhibition of DDR sensor kinases revealed the persistence of γ-H2Ax foci in CDDP-IR treated cells is independent of kinase activation. Taken together, our data suggest that delayed repair of DSBs in NSCLC cells treated with CDDP-IR contributes to CDDP radiosensitization and that alterations of the DDR pathways by inhibition of specific DDR kinases can augment CDDP-IR cytotoxicity by a complementary mechanism.
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Affiliation(s)
- Catherine R Sears
- Departments of Medicine, Indiana University School of Medicine, United States.
| | - Sean A Cooney
- School of Health and Rehabilitation Sciences, Indiana University-Purdue University, Indianapolis, Indiana, United States
| | - Helen Chin-Sinex
- Radiation Oncology, Indiana University School of Medicine, United States
| | - Marc S Mendonca
- Radiation Oncology, Indiana University School of Medicine, United States; Medical and Molecular Genetics, Indiana University School of Medicine, United States
| | - John J Turchi
- Departments of Medicine, Indiana University School of Medicine, United States; Biochemistry and Molecular Biology, Indiana University School of Medicine, United States
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NSCLC cells demonstrate differential mode of cell death in response to the combined treatment of radiation and a DNA-PKcs inhibitor. Oncotarget 2016; 6:3848-60. [PMID: 25714019 PMCID: PMC4414158 DOI: 10.18632/oncotarget.2975] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2014] [Accepted: 12/20/2014] [Indexed: 12/19/2022] Open
Abstract
The current standard of care for lung cancer consists of concurrent chemotherapy and radiation. Several studies have shown that the DNA-PKcs inhibitor NU7441 is a highly potent radiosensitizer, however, the mechanism of NU7441's anti-proliferation effect has not been fully elucidated. In this study, the combined effect of NU7441 and ionizing radiation (IR) in a panel of non-small cell lung cancer cell lines (A549, H460 and H1299) has been investigated. We found that NU7441 significantly enhances the effect of IR in all cell lines. The notable findings in response to this combined treatment are (i) prolonged delay in IR-induced DNA DSB repair, (ii) induced robust G2/M checkpoint, (iii) increased aberrant mitosis followed by mitotic catastrophe specifically in H1299, (iv) dramatically induced autophagy in A549 and (v) IR-induced senescence specifically in H460. H1299 cells show greater G2 checkpoint adaptation after combined treatment, which can be attributed to higher expression level of Plk1 compared to A549 and H460. The enhanced autophagy after NU7441 treatment in A549 is possibly due to the higher endogenous expression of pS6K compared to H1299 and H460 cells. In conclusion, choice of cell death pathway is dependent on the mutation status and other genetic factors of the cells treated.
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22
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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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Dungl DA, Maginn EN, Stronach EA. Preventing Damage Limitation: Targeting DNA-PKcs and DNA Double-Strand Break Repair Pathways for Ovarian Cancer Therapy. Front Oncol 2015. [PMID: 26579492 DOI: 10.3389/fonc.2015.00240] [] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Platinum-based chemotherapy is the cornerstone of ovarian cancer treatment, and its efficacy is dependent on the generation of DNA damage, with subsequent induction of apoptosis. Inappropriate or aberrant activation of the DNA damage response network is associated with resistance to platinum, and defects in DNA repair pathways play critical roles in determining patient response to chemotherapy. In ovarian cancer, tumor cell defects in homologous recombination - a repair pathway activated in response to double-strand DNA breaks (DSB) - are most commonly associated with platinum-sensitive disease. However, despite initial sensitivity, the emergence of resistance is frequent. Here, we review strategies for directly interfering with DNA repair pathways, with particular focus on direct inhibition of non-homologous end joining (NHEJ), another DSB repair pathway. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a core component of NHEJ and it has shown considerable promise as a chemosensitization target in numerous cancer types, including ovarian cancer where it functions to promote platinum-induced survival signaling, via AKT activation. The development of pharmacological inhibitors of DNA-PKcs is on-going, and clinic-ready agents offer real hope to patients with chemoresistant disease.
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Affiliation(s)
- Daniela A Dungl
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
| | - Elaina N Maginn
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
| | - Euan A Stronach
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
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Dungl DA, Maginn EN, Stronach EA. Preventing Damage Limitation: Targeting DNA-PKcs and DNA Double-Strand Break Repair Pathways for Ovarian Cancer Therapy. Front Oncol 2015. [PMID: 26579492 DOI: 10.3389/fonc.2015.00240]+[] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Platinum-based chemotherapy is the cornerstone of ovarian cancer treatment, and its efficacy is dependent on the generation of DNA damage, with subsequent induction of apoptosis. Inappropriate or aberrant activation of the DNA damage response network is associated with resistance to platinum, and defects in DNA repair pathways play critical roles in determining patient response to chemotherapy. In ovarian cancer, tumor cell defects in homologous recombination - a repair pathway activated in response to double-strand DNA breaks (DSB) - are most commonly associated with platinum-sensitive disease. However, despite initial sensitivity, the emergence of resistance is frequent. Here, we review strategies for directly interfering with DNA repair pathways, with particular focus on direct inhibition of non-homologous end joining (NHEJ), another DSB repair pathway. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a core component of NHEJ and it has shown considerable promise as a chemosensitization target in numerous cancer types, including ovarian cancer where it functions to promote platinum-induced survival signaling, via AKT activation. The development of pharmacological inhibitors of DNA-PKcs is on-going, and clinic-ready agents offer real hope to patients with chemoresistant disease.
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Affiliation(s)
- Daniela A Dungl
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
| | - Elaina N Maginn
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
| | - Euan A Stronach
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
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Mitotic catastrophe and cancer drug resistance: A link that must to be broken. Drug Resist Updat 2015; 24:1-12. [PMID: 26830311 DOI: 10.1016/j.drup.2015.11.002] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2015] [Revised: 10/23/2015] [Accepted: 11/06/2015] [Indexed: 01/28/2023]
Abstract
An increased tendency of genomic alterations during the life cycle of cells leads to genomic instability, which is a major driving force for tumorigenesis. A considerable fraction of tumor cells are tetraploid or aneuploid, which renders them intrinsically susceptible to mitotic aberrations, and hence, are particularly sensitive to the induction of mitotic catastrophe. Resistance to cell death is also closely linked to genomic instability, as it enables malignant cells to expand even in a stressful environment. Currently it is known that cells can die via multiple mechanisms. Mitotic catastrophe represents a step preceding apoptosis or necrosis, depending on the expression and/or proper function of several proteins. Mitotic catastrophe was proposed to be an onco-suppressive mechanism and the evasion of mitotic catastrophe constitutes one of the gateways to cancer development. Thus, stimulation of mitotic catastrophe appears to be a promising strategy in cancer treatment. Indeed, several chemotherapeutic drugs are currently used at concentrations that induce apoptosis irrespective of the cell cycle phase, yet are very efficient at triggering mitotic catastrophe at lower doses, significantly limiting side effects. In the present review we summarize current data concerning the role of mitotic catastrophe in cancer drug resistance and discuss novel strategies to break this link.
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Ma H, Takahashi A, Yoshida Y, Adachi A, Kanai T, Ohno T, Nakano T. Combining carbon ion irradiation and non-homologous end-joining repair inhibitor NU7026 efficiently kills cancer cells. Radiat Oncol 2015; 10:225. [PMID: 26553138 PMCID: PMC4638098 DOI: 10.1186/s13014-015-0536-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/03/2015] [Indexed: 11/21/2022] Open
Abstract
Background Our previous data demonstrated that targeting non-homologous end-joining repair (NHEJR) yields a higher radiosensitivity than targeting homologous recombination repair (HRR) to heavy ions using DNA repair gene knockouts (KO) in mouse embryonic fibroblast (MEF). In this study, we determined if combining the use of an NHEJR inhibitor with carbon (C) ion irradiation was more efficient in killing human cancer cells compared with only targeting a HRR inhibitor. Methods The TP53-null human non-small cell lung cancer cell line H1299 was used for testing the radiosensitizing effect of NHEJR-related DNA-dependent protein kinase (DNA-PK) inhibitor NU7026, HRR-related Rad51 inhibitor B02, or both to C ion irradiation using colony forming assays. The mechanism underlying the inhibitor radiosensitization was determined by flow cytometry after H2AX phosphorylation staining. HRR-related Rad54-KO, NHEJR-related Lig4-KO, and wild-type TP53-KO MEF were also included to confirm the suppressing effect specificity of these inhibitors. Results NU7026 showed significant sensitizing effect to C ion irradiation in a concentration-dependent manner. In contrast, B02 showed a slight sensitizing effect to C ion irradiation. The addition of NU7026 significantly increased H2AX phosphorylation after C ion and x-ray irradiations in H1299 cells, but not B02. NU7026 had no effect on radiosensitivity to Lig4-KO MEF and B02 had no effect on radiosensitivity to Rad54-KO MEF in both irradiations. Conclusion These results suggest that inhibitors targeting the NHEJR pathway could significantly enhance radiosensitivity of human cancer cells to C ion irradiation, rather than targeting the HRR pathway. Electronic supplementary material The online version of this article (doi:10.1186/s13014-015-0536-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Hongyu Ma
- Department of Radiation Oncology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
| | - Akihisa Takahashi
- Gunma University Heavy Ion Medical Center, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
| | - Yukari Yoshida
- Gunma University Heavy Ion Medical Center, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
| | - Akiko Adachi
- Department of Radiation Oncology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
| | - Tatsuaki Kanai
- Gunma University Heavy Ion Medical Center, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
| | - Tatsuya Ohno
- Gunma University Heavy Ion Medical Center, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
| | - Takashi Nakano
- Department of Radiation Oncology, Gunma University Graduate School of Medicine, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan. .,Gunma University Heavy Ion Medical Center, 3-39-22 Showa-machi, Maebashi, 371-8511, Gunma, Japan.
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Dungl DA, Maginn EN, Stronach EA. Preventing Damage Limitation: Targeting DNA-PKcs and DNA Double-Strand Break Repair Pathways for Ovarian Cancer Therapy. Front Oncol 2015; 5:240. [PMID: 26579492 PMCID: PMC4620694 DOI: 10.3389/fonc.2015.00240] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2015] [Accepted: 10/10/2015] [Indexed: 12/22/2022] Open
Abstract
Platinum-based chemotherapy is the cornerstone of ovarian cancer treatment, and its efficacy is dependent on the generation of DNA damage, with subsequent induction of apoptosis. Inappropriate or aberrant activation of the DNA damage response network is associated with resistance to platinum, and defects in DNA repair pathways play critical roles in determining patient response to chemotherapy. In ovarian cancer, tumor cell defects in homologous recombination – a repair pathway activated in response to double-strand DNA breaks (DSB) – are most commonly associated with platinum-sensitive disease. However, despite initial sensitivity, the emergence of resistance is frequent. Here, we review strategies for directly interfering with DNA repair pathways, with particular focus on direct inhibition of non-homologous end joining (NHEJ), another DSB repair pathway. DNA-dependent protein kinase catalytic subunit (DNA-PKcs) is a core component of NHEJ and it has shown considerable promise as a chemosensitization target in numerous cancer types, including ovarian cancer where it functions to promote platinum-induced survival signaling, via AKT activation. The development of pharmacological inhibitors of DNA-PKcs is on-going, and clinic-ready agents offer real hope to patients with chemoresistant disease.
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Affiliation(s)
- Daniela A Dungl
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
| | - Elaina N Maginn
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
| | - Euan A Stronach
- Molecular Therapy Laboratory, Department of Surgery and Cancer, Ovarian Cancer Action Research Centre, Imperial College London , London , UK
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Felgueiras J, Fardilha M. Phosphoprotein phosphatase 1-interacting proteins as therapeutic targets in prostate cancer. World J Pharmacol 2014; 3:120-139. [DOI: 10.5497/wjp.v3.i4.120] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2014] [Revised: 09/01/2014] [Accepted: 09/24/2014] [Indexed: 02/06/2023] Open
Abstract
Prostate cancer is a major public health concern worldwide, being one of the most prevalent cancers in men. Great improvements have been made both in terms of early diagnosis and therapeutics. However, there is still an urgent need for reliable biomarkers that could overcome the lack of cancer-specificity of prostate-specific antigen, as well as alternative therapeutic targets for advanced metastatic cases. Reversible phosphorylation of proteins is a post-translational modification critical to the regulation of numerous cellular processes. Phosphoprotein phosphatase 1 (PPP1) is a major serine/threonine phosphatase, whose specificity is determined by its interacting proteins. These interactors can be PPP1 substrates, regulators, or even both. Deregulation of this protein-protein interaction network alters cell dynamics and underlies the development of several cancer hallmarks. Therefore, the identification of PPP1 interactome in specific cellular context is of crucial importance. The knowledge on PPP1 complexes in prostate cancer remains scarce, with only 4 holoenzymes characterized in human prostate cancer models. However, an increasing number of PPP1 interactors have been identified as expressed in human prostate tissue, including the tumor suppressors TP53 and RB1. Efforts should be made in order to identify the role of such proteins in prostate carcinogenesis, since only 26 have yet well-recognized roles. Here, we revise literature and human protein databases to provide an in-depth knowledge on the biological significance of PPP1 complexes in human prostate carcinogenesis and their potential use as therapeutic targets for the development of new therapies for prostate cancer.
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Ramzan Z, Nassri AB, Huerta S. Genotypic characteristics of resistant tumors to pre-operative ionizing radiation in rectal cancer. World J Gastrointest Oncol 2014; 6:194-210. [PMID: 25024812 PMCID: PMC4092337 DOI: 10.4251/wjgo.v6.i7.194] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2013] [Revised: 03/19/2014] [Accepted: 05/08/2014] [Indexed: 02/05/2023] Open
Abstract
Due to a wide range of clinical response in patients undergoing neo-adjuvant chemoradiation for rectal cancer it is essential to understand molecular factors that lead to the broad response observed in patients receiving the same form of treatment. Despite extensive research in this field, the exact mechanisms still remain elusive. Data raging from DNA-repair to specific molecules leading to cell survival as well as resistance to apoptosis have been investigated. Individually, or in combination, there is no single pathway that has become clinically applicable to date. In the following review, we describe the current status of various pathways that might lead to resistance to the therapeutic applications of ionizing radiation in rectal cancer.
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Flassig RJ, Maubach G, Täger C, Sundmacher K, Naumann M. Experimental design, validation and computational modeling uncover DNA damage sensing by DNA-PK and ATM. MOLECULAR BIOSYSTEMS 2014; 10:1978-86. [PMID: 24833308 DOI: 10.1039/c4mb00093e] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Reliable and efficient detection of DNA damage constitutes a vital capability of human cells to maintain genome stability. Following DNA damage, the histone variant H2AX becomes rapidly phosphorylated by the DNA damage response kinases DNA-PKcs and ATM. H2AX phosphorylation plays a central role in signal amplification leading to chromatin remodeling and DNA repair initiation. The contribution of DNA-PKcs and ATM to H2AX phosphorylation is however puzzling. Although ATM is required, DNA-PKcs can substitute for it. Here we analyze the interplay between DNA-PKcs and ATM with a computational model derived by an iterative workflow: switching between experimental design, experiment and model analysis, we generated an extensive set of time-resolved data and identified a conclusive dynamic signaling model out of several alternatives. Our work shows that DNA-PKcs and ATM enforce a biphasic H2AX phosphorylation. DNA-PKcs can be associated to the initial, and ATM to the succeeding phosphorylation phase of H2AX resulting into a signal persistence detection function for reliable damage sensing. Further, our model predictions emphasize that DNA-PKcs inhibition significantly delays H2AX phosphorylation and associated DNA repair initiation.
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Affiliation(s)
- R J Flassig
- Process Systems Engineering Group, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany.
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Azad A, Bukczynska P, Jackson S, Haupt Y, Haput Y, Cullinane C, McArthur GA, Solomon B. Co-targeting deoxyribonucleic acid-dependent protein kinase and poly(adenosine diphosphate-ribose) polymerase-1 promotes accelerated senescence of irradiated cancer cells. Int J Radiat Oncol Biol Phys 2014; 88:385-94. [PMID: 24411611 DOI: 10.1016/j.ijrobp.2013.10.043] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Revised: 10/29/2013] [Accepted: 10/31/2013] [Indexed: 01/11/2023]
Abstract
PURPOSE To examine the effects of combined blockade of DNA-dependent protein kinase (DNA-PK) and poly(adenosine diphosphate-ribose) polymerase-1 (PARP-1) on accelerated senescence in irradiated H460 and A549 non-small cell lung cancer cells. METHODS AND MATERIALS The effects of KU5788 and AG014699 (inhibitors of DNA-PK and PARP-1, respectively) on clonogenic survival, DNA double-strand breaks (DSBs), apoptosis, mitotic catastrophe, and accelerated senescence in irradiated cells were examined in vitro. For in vivo experiments, H460 xenografts established in athymic nude mice were treated with BEZ235 (a DNA-PK, ATM, and phosphatidylinositol 3-kinase/mammalian target of rapamycin inhibitor) and AG014699 to determine effects on proliferation, DNA DSBs, and accelerated senescence after radiation. RESULTS Compared with either inhibitor alone, combination treatment with KU57788 and AG014699 reduced postradiation clonogenic survival and significantly increased persistence of Gamma-H2AX (γH2AX) foci in irradiated H460 and A549 cells. Notably, these effects coincided with the induction of accelerated senescence in irradiated cells as reflected by positive β-galactosidase staining, G2-M cell-cycle arrest, enlarged and flattened cellular morphology, increased p21 expression, and senescence-associated cytokine secretion. In irradiated H460 xenografts, concurrent therapy with BEZ235 and AG014699 resulted in sustained Gamma-H2AX (γH2AX) staining and prominent β-galactosidase activity. CONCLUSION Combined DNA-PK and PARP-1 blockade increased tumor cell radiosensitivity and enhanced the prosenescent properties of ionizing radiation in vitro and in vivo. These data provide a rationale for further preclinical and clinical testing of this therapeutic combination.
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Affiliation(s)
- Arun Azad
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Pathology, St. Vincent's Hospital, University of Melbourne, Parkville, Victoria, Australia.
| | - Patricia Bukczynska
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Susan Jackson
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia
| | - Ygal Haupt
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Ygal Haput
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Carleen Cullinane
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Grant A McArthur
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Division of Cancer Medicine, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Medicine, St. Vincent's Hospital, University of Melbourne, Parkville, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
| | - Benjamin Solomon
- Division of Cancer Research, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Division of Cancer Medicine, Peter MacCallum Cancer Centre, East Melbourne, Victoria, Australia; Department of Medicine, St. Vincent's Hospital, University of Melbourne, Parkville, Victoria, Australia; Sir Peter MacCallum Department of Oncology, University of Melbourne, Parkville, Victoria, Australia
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Tichy A, Durisova K, Salovska B, Pejchal J, Zarybnicka L, Vavrova J, Dye NA, Sinkorova Z. Radio-sensitization of human leukaemic MOLT-4 cells by DNA-dependent protein kinase inhibitor, NU7441. RADIATION AND ENVIRONMENTAL BIOPHYSICS 2014; 53:83-92. [PMID: 24100951 DOI: 10.1007/s00411-013-0494-5] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Accepted: 09/17/2013] [Indexed: 06/02/2023]
Abstract
We studied the effect of pre-incubation with NU7441, a specific inhibitor of DNA-dependent protein kinase (DNA-PK), on molecular mechanisms triggered by ionizing radiation (IR). The experimental design involved four groups of human T-lymphocyte leukaemic MOLT-4 cells: control, NU7441-treated (1 μM), IR-treated (1 Gy), and combination of NU7441 and IR. We used flow cytometry for apoptosis assessment, Western blotting and ELISA for detection of proteins involved in DNA repair signalling and epifluorescence microscopy for detection of IR-induced phosphorylation of histone H2A.X. We did not observe any major changes in the amount of DNA-PK subunits Ku70/80 caused by the combination of NU7441 and radiation. Their combination led to an increased phosphorylation of H2A.X, a hallmark of DNA damage. However, it did not prevent up-regulation of neither p53 (and its phosphorylation at Ser 15 and 392) nor p21. We observed a decrease in the levels of anti-apoptotic Mcl-1, cdc25A phosphatase, cleavage of PARP and a significant increase in apoptosis in the group treated with combination. In conclusion, the combination of NU7441 with IR caused increased phosphorylation of H2A.X early after irradiation and subsequent induction of apoptosis. It was efficient in MOLT-4 cells in 10× lower concentration than the inhibitor NU7026. NU7441 proved as a potent radio-sensitizing agent, and it might provide a platform for development of new radio-sensitizers in radiotherapy.
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Affiliation(s)
- Ales Tichy
- Department of Radiobiology, Faculty of Health Sciences in Hradec Kralove, University of Defence in Brno, Brno, Czech Republic,
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Curtin NJ. Inhibiting the DNA damage response as a therapeutic manoeuvre in cancer. Br J Pharmacol 2014; 169:1745-65. [PMID: 23682925 DOI: 10.1111/bph.12244] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Accepted: 03/20/2013] [Indexed: 01/05/2023] Open
Abstract
UNLABELLED The DNA damage response (DDR), consisting of an orchestrated network of proteins effecting repair and signalling to cell cycle arrest, to allow time to repair, is essential for cell viability and to prevent DNA damage being passed on to daughter cells. The DDR is dysregulated in cancer with some pathways up-regulated and others down-regulated or lost. Up-regulated pathways can confer resistance to anti-cancer DNA damaging agents. Therefore, inhibitors of key components of these pathways have the potential to prevent this therapeutic resistance. Conversely, defects in a particular DDR pathway may lead to dependence on a complementary pathway. Inhibition of this complementary pathway may result in tumour-specific cell killing. Thus, inhibitors of the DDR have the potential to increase the efficacy of DNA damaging chemotherapy and radiotherapy and have single-agent activity against tumours with a specific DDR defect. This review describes the compounds that have been designed to inhibit specific DDR targets and summarizes the pre-clinical and clinical evaluation of these inhibitors of DNA damage signalling and repair. LINKED ARTICLES This article is part of a themed section on Emerging Therapeutic Aspects in Oncology. To view the other articles in this section visit http://dx.doi.org/10.1111/bph.2013.169.issue-8.
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Affiliation(s)
- N J Curtin
- Northern Institute for Cancer Research, Medical School, Newcastle University, Newcastle upon Tyne, UK.
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DNA-PK inhibition by NU7441 sensitizes breast cancer cells to ionizing radiation and doxorubicin. Breast Cancer Res Treat 2013; 143:47-55. [DOI: 10.1007/s10549-013-2785-6] [Citation(s) in RCA: 85] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Accepted: 11/21/2013] [Indexed: 10/26/2022]
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Frank AO, Feldkamp MD, Kennedy JP, Waterson AG, Pelz NF, Patrone JD, Vangamudi B, Camper DV, Rossanese OW, Chazin WJ, Fesik SW. Discovery of a potent inhibitor of replication protein a protein-protein interactions using a fragment-linking approach. J Med Chem 2013; 56:9242-50. [PMID: 24147804 DOI: 10.1021/jm401333u] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Replication protein A (RPA), the major eukaryotic single-stranded DNA (ssDNA)-binding protein, is involved in nearly all cellular DNA transactions. The RPA N-terminal domain (RPA70N) is a recruitment site for proteins involved in DNA-damage response and repair. Selective inhibition of these protein-protein interactions has the potential to inhibit the DNA-damage response and to sensitize cancer cells to DNA-damaging agents without affecting other functions of RPA. To discover a potent, selective inhibitor of the RPA70N protein-protein interactions to test this hypothesis, we used NMR spectroscopy to identify fragment hits that bind to two adjacent sites in the basic cleft of RPA70N. High-resolution X-ray crystal structures of RPA70N-ligand complexes revealed how these fragments bind to RPA and guided the design of linked compounds that simultaneously occupy both sites. We have synthesized linked molecules that bind to RPA70N with submicromolar affinity and minimal disruption of RPA's interaction with ssDNA.
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Affiliation(s)
- Andreas O Frank
- Department of Biochemistry, Vanderbilt University School of Medicine , Nashville, Tennessee 37232-0146, United States
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Vávrová J, Zárybnická L, Lukášová E, Řezáčová M, Novotná E, Sinkorová Z, Tichý A, Pejchal J, Durišová K. Inhibition of ATR kinase with the selective inhibitor VE-821 results in radiosensitization of cells of promyelocytic leukaemia (HL-60). RADIATION AND ENVIRONMENTAL BIOPHYSICS 2013; 52:471-479. [PMID: 23934411 DOI: 10.1007/s00411-013-0486-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Accepted: 07/31/2013] [Indexed: 06/02/2023]
Abstract
We compared the effects of inhibitors of kinases ATM (KU55933) and ATR (VE-821) (incubated for 30 min before irradiation) on the radiosensitization of human promyelocyte leukaemia cells (HL-60), lacking functional protein p53. VE-821 reduces phosphorylation of check-point kinase 1 at serine 345, and KU55933 reduces phosphorylation of check-point kinase 2 on threonine 68 as assayed 4 h after irradiation by the dose of 6 Gy. Within 24 h after gamma-irradiation with a dose of 3 Gy, the cells accumulated in the G2 phase (67 %) and the number of cells in S phase decreased. KU55933 (10 μM) did not affect the accumulation of cells in G2 phase and did not affect the decrease in the number of cells in S phase after irradiation. VE-821 (2 and 10 μM) reduced the number of irradiated cells in the G2 phase to the level of non-irradiated cells and increased the number of irradiated cells in S phase, compared to irradiated cells not treated with inhibitors. In the 144 h interval after irradiation with 3 Gy, there was a considerable induction of apoptosis in the VE-821 group (10 μM). The repair of the radiation damage, as observed 72 h after irradiation, was more rapid in the group exposed solely to irradiation and in the group treated with KU55933 (80 and 77 % of cells, respectively, were free of DSBs), whereas in the group incubated with 10 μM VE-821, there were only 61 % of cells free of DSBs. The inhibition of kinase ATR with its specific inhibitor VE-821 resulted in a more pronounced radiosensitizing effect in HL-60 cells as compared to the inhibition of kinase ATM with the inhibitor KU55933. In contrast to KU55933, the VE-821 treatment prevented HL-60 cells from undergoing G2 cell cycle arrest. Taken together, we conclude that the ATR kinase inhibition offers a new possibility of radiosensitization of tumour cells lacking functional protein p53.
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Affiliation(s)
- Jiřina Vávrová
- Department of Radiobiology, Faculty of Health Sciences, University of Defence, Hradec Králové, Brno, Czech Republic,
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DAB2IP regulates autophagy in prostate cancer in response to combined treatment of radiation and a DNA-PKcs inhibitor. Neoplasia 2013; 14:1203-12. [PMID: 23308052 DOI: 10.1593/neo.121310] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 10/10/2012] [Accepted: 10/12/2012] [Indexed: 01/08/2023] Open
Abstract
Radiation therapy (RT) is an effective strategy for the treatment of localized prostate cancer (PCa) as well as local invasion. However, some locally advanced cancers develop radiation resistance and recur after therapy; therefore, the development of radiation-sensitizing compounds is essential for treatment of these tumors. DOC-2/DAB2 interactive protein (DAB2IP), which is a novel member of the Ras-GTPase activating protein family and a regulator of phosphatidylinositol 3-kinase-Akt activity, is often downregulated in aggressive PCa. Our previous studies have shown that loss of DAB2IP results in radioresistance in PCa cells primarily because of accelerated DNA double-strand break (DSB) repair kinetics, robust G(2)/M checkpoint control, and evasion of apoptosis. A novel DNA-PKcs inhibitor NU7441 can significantly enhance the effect of radiation in DAB2IP-deficient PCa cells. This enhanced radiation sensitivity after NU7441 treatment is primarily due to delayed DNA DSB repair. More significantly, we found that DAB2IP-deficient PCa cells show dramatic induction of autophagy after treatment with radiation and NU7441. However, restoring DAB2IP expression in PCa cells resulted in decreased autophagy-associated proteins, such as LC3B and Beclin 1, as well as decreased phosphorylation of S6K and mammalian target of rapamycin (mTOR). Furthermore, the presence of DAB2IP in PCa cells can lead to more apoptosis in response to combined treatment of NU7441 and ionizing radiation. Taken together, NU7441 is a potent radiosensitizer in aggressive PCa cells and DAB2IP plays a critical role in enhancing PCa cell death after combined treatment with NU7441 and radiation.
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Abstract
In this article, we investigate the thermal degradation of deoxyribonucleic acid (DNA). We find that under dry conditions, complete DNA degradation occurs at above 190°C. In addition, as the boiling temperature of water is pressure dependent, we have investigated the thermal degradation of the DNA in water for different applied partial pressures. This information is important for fundamental understanding of DNA structure and energetics, and can be useful for biomedical applications such as thermal targeting of DNA in cancer cells, as well as for basic research.
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Affiliation(s)
- Moshe Karni
- Faculty of Engineering, Bar Ilan University, Ramat-Gan, Israel
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Xie X, Guo J, Kong Y, Xie GX, Li L, Lv N, Xiao X, Tang J, Wang X, Liu P, Yang M, Xie Z, Wei W, Spencer DM, Xie X. Targeted expression of Escherichia coli purine nucleoside phosphorylase and Fludara® for prostate cancer therapy. J Gene Med 2013; 13:680-91. [PMID: 22009763 DOI: 10.1002/jgm.1620] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022] Open
Abstract
BACKGROUND Previous studies have shown that Herpes Simplex Virus thymidine kinase (HSV-tk)/ganciclovir (GCV) comprised the most commonly used suicide gene therapy for prostate cancer, with modest results being obtained. However, novel suicide genes, such as Escherichia coli purine nucleoside phosphorylase (PNP), have been utilized to demonstrate more potent tumor killing and an enhanced bystander effect on local, non-expressing cells compared to HSV-tk. METHODS PNP/fludarabine (Fludara®; fludarabine phosphate; Berlex Labs, Richmond, CA, USA) was deliveried by prostate-specific, rat probasin-based promoter, ARR2PB. After infection of various cell lines with ADV.ARR(2) PB-PNP and administration of androgen analog, R1881, expression of PNP mRNA was detected; in vivo, the antitumor effect of the ARR(2) PB-PNP/Fludara system was monitored and analyzed, as well as animal survival. RESULTS After in vitro infection with ADV.ARR(2) PB-PNP (multiplicity of infection = 10), LNCaP cells were more sensitive to a lower concentration Fludara (LD(50) , approximately 0.1 µg/ml) in the presence of R1881. Furthermore, robust bystander effects after R1881/Fludara treatment were observed in LNCaP cells after infection with bicistronic vector ADV.ARR2PB/PNP-IRES-EGFP in contrast to a much weaker effect in cells treated with ADV.CMV-HSV-tk/GCV. In vivo, tumor size in the ADV.ARR2PB-PNP/Fludara treatment group was dramatically smaller than in the control groups, and the mice treated with our system had a significantly prolonged survival, with three of eight mice surviving up to the 160-day termination point, as well as no systemic toxicity. CONCLUSIONS The ARR(2) PB-PNP/Fludara system induced massive tumor cell death and a prolonged life span without systemic cytotoxicity; therefore, it might be a more attractive strategy for suicide gene therapy of prostate cancer.
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Affiliation(s)
- Xinhua Xie
- State Key Laboratory of Oncology in South China, Sun Yat-Sen University Cancer Center, Guangzhou, China; Department of Breast Oncology, Sun Yat-Sen University Cancer Center, Guangzhou, China
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Willard SS, Koochekpour S. Regulators of gene expression as biomarkers for prostate cancer. Am J Cancer Res 2012; 2:620-657. [PMID: 23226612 PMCID: PMC3512182] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2012] [Accepted: 10/09/2012] [Indexed: 06/01/2023] Open
Abstract
Recent technological advancements in gene expression analysis have led to the discovery of a promising new group of prostate cancer (PCa) biomarkers that have the potential to influence diagnosis and the prediction of disease severity. The accumulation of deleterious changes in gene expression is a fundamental mechanism of prostate carcinogenesis. Aberrant gene expression can arise from changes in epigenetic regulation or mutation in the genome affecting either key regulatory elements or gene sequences themselves. At the epigenetic level, a myriad of abnormal histone modifications and changes in DNA methylation are found in PCa patients. In addition, many mutations in the genome have been associated with higher PCa risk. Finally, over- or underexpression of key genes involved in cell cycle regulation, apoptosis, cell adhesion and regulation of transcription has been observed. An interesting group of biomarkers are emerging from these studies which may prove more predictive than the standard prostate specific antigen (PSA) serum test. In this review, we discuss recent results in the field of gene expression analysis in PCa including the most promising biomarkers in the areas of epigenetics, genomics and the transcriptome, some of which are currently under investigation as clinical tests for early detection and better prognostic prediction of PCa.
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Affiliation(s)
- Stacey S Willard
- Departments of Cancer Genetics and Urology, Center for Genetics and Pharmacology, Roswell Park Cancer Institute Elm and Carlton Streets, Buffalo, NY, USA
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Korwek Z, Sewastianik T, Bielak-Zmijewska A, Mosieniak G, Alster O, Moreno-Villanueva M, Burkle A, Sikora E. Inhibition of ATM blocks the etoposide-induced DNA damage response and apoptosis of resting human T cells. DNA Repair (Amst) 2012; 11:864-73. [PMID: 23058634 DOI: 10.1016/j.dnarep.2012.08.006] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2012] [Revised: 07/27/2012] [Accepted: 08/21/2012] [Indexed: 12/22/2022]
Abstract
It is believed that normal cells with an unaffected DNA damage response (DDR) and DNA damage repair machinery, could be less prone to DNA damaging treatment than cancer cells. However, the anticancer drug, etoposide, which is a topoisomerase II inhibitor, can generate DNA double strand breaks affecting not only replication but also transcription and therefore can induce DNA damage in non-replicating cells. Indeed, we showed that etoposide could influence transcription and was able to activate DDR in resting human T cells by inducing phosphorylation of ATM and its substrates, H2AX and p53. This led to activation of PUMA, caspases and to apoptotic cell death. Lymphoblastoid leukemic Jurkat cells, as cycling cells, were more sensitive to etoposide considering the level of DNA damage, DDR and apoptosis. Next, we used ATM inhibitor, KU 55933, which has been shown previously to be a radio/chemo-sensitizing agent. Pretreatment of resting T cells with KU 55933 blocked phosphorylation of ATM, H2AX and p53, which, in turn, prevented PUMA expression, caspase activation and apoptosis. On the other hand, KU 55933 incremented apoptosis of Jurkat cells. However, etoposide-induced DNA damage in resting T cells was not influenced by KU 55933 as revealed by the FADU assay. Altogether our results show that KU 55933 blocks DDR and apoptosis induced by etoposide in normal resting T cells, but increased cytotoxic effect on proliferating leukemic Jurkat cells. We discuss the possible beneficial and adverse effects of drugs affecting the DDR in cancer cells that are currently in preclinical anticancer trials.
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Affiliation(s)
- Z Korwek
- Laboratory of the Molecular Bases of Ageing, Nencki Institute of Experimental Biology, Polish Academy of Sciences, 02-093 Warsaw, Poland
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Monitoring the subcellular localization of doxorubicin in CHO-K1 using MEKC−LIF: Liposomal carrier for enhanced drug delivery. Talanta 2012; 99:683-8. [DOI: 10.1016/j.talanta.2012.06.077] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 06/25/2012] [Accepted: 06/26/2012] [Indexed: 11/23/2022]
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Yen CY, Chiu CC, Haung RW, Yeh CC, Huang KJ, Chang KF, Hseu YC, Chang FR, Chang HW, Wu YC. Antiproliferative effects of goniothalamin on Ca9-22 oral cancer cells through apoptosis, DNA damage and ROS induction. Mutat Res 2012; 747:253-8. [PMID: 22721813 DOI: 10.1016/j.mrgentox.2012.06.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2011] [Revised: 06/05/2012] [Accepted: 06/10/2012] [Indexed: 01/10/2023]
Abstract
Goniothalamin (GTN), a plant bioactive styryl-lactone, is a natural product with potent anti-tumorigenesis effects for several types of cancer. Nonetheless, the anticancer effect of GTN has not been examined in oral cancer. The present study was designed to evaluate its potential anticancer effects in an oral squamous cell carcinoma (OSCC) model and to determine the possible mechanisms with respect to apoptosis, DNA damage, reactive oxygen species (ROS) induction, and mitochondrial membrane potential. Our data demonstrated that cell proliferation was significantly inhibited by GTN in Ca9-22 OSCC cancer cells in concentration- and time-dependent manners (p<0.05). For cell cycle and apoptotic effects of GTN-treated Ca9-22 cancer cells, the sub-G1 population and annexin V-intensity significantly increased in a concentration-dependent manner (p<0.001). For the analysis of DNA double strand breaks, γH2AX intensity significantly increased in GTN-treated Ca9-22 cancer cells in concentration-response relationship (p<0.05). Moreover, GTN significantly induced intracellular ROS levels in Ca9-22 cancer cells in a concentration- and time-dependent manner (p<0.05). For membrane depolarization of mitochondria, the DiOC(2)(3) (3,3'-diethyloxacarbocyanine iodide) intensity of GTN-treated Ca9-22 cancer cells was significantly decreased in concentration- and time-dependent relationships (p<0.001). Taken together, these results suggest that the anticancer effect of GTN against oral cancer cells is valid and GTN-induced growth inhibition and apoptosis influence the downstream cascade including ROS induction, DNA damage, and mitochondria membrane depolarization. Therefore, GTN has potential as a chemotherapeutic agent against oral cancer.
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Affiliation(s)
- Ching-Yu Yen
- Department of Oral and Maxillofacial Surgery, Chi-Mei Medical Center, Tainan, Taiwan
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Hsu FM, Zhang S, Chen BPC. Role of DNA-dependent protein kinase catalytic subunit in cancer development and treatment. Transl Cancer Res 2012; 1:22-34. [PMID: 22943041 DOI: 10.3978/j.issn.2218-676x.2012.04.01] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a key component of the non-homologous end-joining (NHEJ) pathway, is involved in DNA double-strand break repair, immunocompetence, genomic integrity, and epidermal growth factor receptor signaling. Clinical studies indicate that expression and activity of DNA-PKcs is correlated with cancer progression and response to treatment. Various anti-DNA-PKcs strategies have been developed and tested in preclinical studies to exploit the benefit of DNA-PKcs inhibition in sensitization of radiotherapy and in combined modality therapy with other antitumor agents. In this article, we review the association between DNA-PKcs and cancer development and discuss current approaches and mechanisms for inhibition of DNA-PKcs. The future challenges are to understand how DNA-PKcs activity is correlated with cancer susceptibility and to identify those patients who would most benefit from DNA-PKcs inhibition.
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Affiliation(s)
- Feng-Ming Hsu
- Department of Oncology, National Taiwan University Hospital, National Taiwan University College of Medicine, Taipei, Taiwan
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45
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Drug Release Patterns and Cytotoxicity of PEG-poly(aspartate) Block Copolymer Micelles in Cancer Cells. Pharm Res 2012; 29:1755-67. [DOI: 10.1007/s11095-012-0697-5] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2011] [Accepted: 01/27/2012] [Indexed: 12/22/2022]
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Upon the tightrope in prostate cancer: two acrobats on the same tightrope to cross the finishline. Mol Cell Biochem 2011; 364:53-7. [PMID: 22200977 DOI: 10.1007/s11010-011-1204-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2011] [Accepted: 12/15/2011] [Indexed: 01/03/2023]
Abstract
Prostate cancer is a multifactorial, multistep progressive disorder that is undruggable to date because of stumbling blocks in the standardization of therapy. It is triggered by a broad range of proteins, signaling networks and DNA damage response modulators. It is becoming increasingly apparent that DNA repair mediators have split personalities, as they are instrumental in suppressing and promoting carcinogenesis. In this article, we discuss on post-transcriptional processing of regulators of DNA damage response, and how DNA repair proteins trigger shuttling of androgen receptor. Substantial fraction of information has been added into the existing literature of ATM biology; however, the particular area of post-transcriptional processing errors and gene therapy for reprogramming of ATM has been left unaddressed in prostate cancer. It is therefore noteworthy that the facet of targeting strategy, antisense morpholino oligonucleotides chemistry, and systematic delivery of AOs has promising outlook in splice-targeted antisense-mediated therapy.
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