1
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Puentes LN, Lengyel-Zhand Z, Lee JY, Hsieh CJ, Schneider ME, Edwards KJ, Luk KC, Lee VMY, Trojanowski JQ, Mach RH. Poly (ADP-ribose) Interacts With Phosphorylated α-Synuclein in Post Mortem PD Samples. Front Aging Neurosci 2021; 13:704041. [PMID: 34220490 PMCID: PMC8249773 DOI: 10.3389/fnagi.2021.704041] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2021] [Accepted: 05/26/2021] [Indexed: 12/12/2022] Open
Abstract
Poly (ADP-ribose) (PAR) is a negatively charged polymer that is biosynthesized by Poly (ADP-ribose) Polymerase-1 (PARP-1) and regulates various cellular processes. Alpha-synuclein (αSyn) is an intrinsically disordered protein (IDP) that has been directly implicated with driving the onset and progression of Parkinson's disease (PD). The mechanisms by which α-synuclein (αSyn) elicits its neurotoxic effects remain unclear, though it is well established that the main components of Lewy bodies (LBs) and Lewy neurites (LNs) in PD patients are aggregated hyperphosphorylated (S129) forms of αSyn (pαSyn). In the present study, we used immunofluorescence-based assays to explore if PARP-1 enzymatic product (PAR) promotes the aberrant cytoplasmic accumulation of pαSyn. We also performed quantitative measurements using in situ proximity ligation assays (PLA) on a transgenic murine model of α-synucleinopathy (M83-SNCA∗A53T) and post mortem PD/PDD patient samples to characterize PAR-pαSyn interactions. Additionally, we used bioinformatic approaches and site-directed mutagenesis to identify PAR-binding regions on αSyn. In summary, our studies show that PAR-pαSyn interactions are predominantly observed in PD-relevant transgenic murine models of αSyn pathology and post mortem PD/PDD patient samples. Moreover, we confirm that the interactions between PAR and αSyn involve electrostatic forces between negatively charged PAR and lysine residues on the N-terminal region of αSyn.
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Affiliation(s)
- Laura N. Puentes
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Zsofia Lengyel-Zhand
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ji Youn Lee
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Chia-Ju Hsieh
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Mark E. Schneider
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Kimberly J. Edwards
- Department of Systems Pharmacology and Translational Therapeutics, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Kelvin C. Luk
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Virginia M.-Y. Lee
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - John Q. Trojanowski
- Department of Pathology and Laboratory Medicine, Institute on Aging and Center for Neurodegenerative Disease Research, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Robert H. Mach
- Department of Radiology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
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2
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Zeng L, Boggs DH, Xing C, Zhang Z, Anderson JC, Wajapeyee N, Veale C, Bredel M, Shi LZ, Bonner JA, Willey CD, Yang ES. Combining PARP and DNA-PK Inhibitors With Irradiation Inhibits HPV-Negative Head and Neck Cancer Squamous Carcinoma Growth. Front Genet 2020; 11:1036. [PMID: 33133138 PMCID: PMC7511754 DOI: 10.3389/fgene.2020.01036] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 08/11/2020] [Indexed: 01/24/2023] Open
Abstract
Novel targeted agents to inhibit DNA repair pathways to sensitize tumors to irradiation (IR) are being investigated as an alternative to chemoradiation for locally advanced human papilloma virus negative (HPV-negative) head and neck squamous cell carcinoma (HNSCC). Two well-characterized targets that, when inhibited, exhibit potent IR sensitization are PARP1 and DNA-PKcs. However, their cooperation in sensitizing HPV-negative HNSCC to IR remains to be explored given that PARP1 and DNA-PkCS bind to unresected stalled DNA replication forks and cooperate to recruit XRCC1 to facilitate double-strand break repair. Here, we show that the combination of the DNA-PK inhibitor NU7441 and the PARP inhibitor olaparib significantly decrease proliferation (61–78%) compared to no reduction with either agent alone (p < 0.001) in both SCC1 and SCC6 cell lines. Adding IR to the combination further decreased cell proliferation (91–92%, p < 0.001) in SCC1 and SCC6. Similar results were observed using long-term colony formation assays [dose enhancement ratio (DER) 2.3–3.2 at 4Gy, p < 0.05]. Reduced cell survival was attributed to increased apoptosis and G2/M cell cycle arrest. Kinomic analysis using tyrosine (PTK) and serine/threonine (STK) arrays reveals that combination treatment results in the most potent inhibition of kinases involved in the CDK and ERK pathways compared to either agent alone. In vivo, a significant delay of tumor growth was observed in UM-SCC1 xenografts receiving IR with olaparib and/or NU7441, which was similar to the cisplatin-IR group. Both regimens were less toxic than cisplatin-IR as assessed by loss of mouse body weight. Taken together, these results demonstrate that the combination of NU7441 and olaparib with IR enhances HPV-negative HNSCC inhibition in both cell culture and in mice, suggesting a potential innovative combination for effectively treating patients with HPV-negative HNSCC.
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Affiliation(s)
- Ling Zeng
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Drexell Hunter Boggs
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Chuan Xing
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Zhuo Zhang
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Joshua C Anderson
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Narendra Wajapeyee
- Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Chris Veale
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Markus Bredel
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Lewis Z Shi
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - James A Bonner
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Christopher D Willey
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,Department of Biochemistry and Molecular Genetics, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
| | - Eddy S Yang
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,O'Neal Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,Department of Cell, Developmental, and Integrative Biology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States.,Department of Pharmacology and Toxicology, University of Alabama at Birmingham School of Medicine, Birmingham, AL, United States
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3
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Xu H, Wang X, Burchiel SW. Toxicity of environmentally-relevant concentrations of arsenic on developing T lymphocyte. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2018; 62:107-113. [PMID: 29986278 DOI: 10.1016/j.etap.2018.07.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Accepted: 07/02/2018] [Indexed: 05/14/2023]
Abstract
Arsenic is a ubiquitous environmental contaminant that exists in many inorganic and organic forms. In particular, arsenite is known to induce immunotoxicity in humans and animals. There are still major gaps in our understanding of the mechanism(s) of the immunotoxicity induced by arsenic at environmentally-relevant concentrations. T cells are an essential part of the immune system required for host resistance to infections and protection from cancer. Developing T cells in the thymus have been shown to be particularly prone to arsenite-induced toxicity at low concentrations. Suppression of DNA repair proteins and oxidative stress have been identified as a mechanism of genotoxicity that occurs at low to moderate concentrations. Inhibition of the IL-7 signaling pathway was thought to be responsible for the non-genotoxicity induced by low to moderate doses of arsenic. Interestingly, T cells at different stages of their development had distinct sensitivities to arsenite, which was regulated by arsenite exporters. The current evidence strongly suggests that low to moderate doses of arsenic induces toxic effects in the developing T cells and accumulates to highest levels in the early cells that are least capable to pump out arsenic, which may be the mechanism of the high arsenic sensitivity. Therefore, quantification of the exposure levels should be encouraged in future arsenic toxicity studies.
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Affiliation(s)
- Huan Xu
- East China University of Science and Technology, School of Pharmacy, Department of Pharmaceutical Sciences, Shanghai, 200237, China.
| | - Xiaolei Wang
- East China University of Science and Technology, School of Pharmacy, Department of Pharmaceutical Sciences, Shanghai, 200237, China
| | - Scott W Burchiel
- The University of New Mexico College of Pharmacy, Department of Pharmaceutical Sciences, Albuquerque, NM, 87131, USA.
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4
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Hastak K, Bhutra S, Parry R, Ford JM. Poly (ADP-ribose) polymerase inhibitor, an effective radiosensitizer in lung and pancreatic cancers. Oncotarget 2018; 8:26344-26355. [PMID: 28412751 PMCID: PMC5432262 DOI: 10.18632/oncotarget.15464] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Accepted: 02/06/2017] [Indexed: 12/25/2022] Open
Abstract
The development of stereotactic body radiation therapy (SBRT) has revolutionized radiation therapy for lung cancers and is an emerging treatment option for pancreatic cancers. However, there are many questions on how to optimize its use in chemoradiotherapy. The most relevant addition to radiotherapy regimens are inhibitors of DNA repair and DNA damage response pathways. One such class of agents are inhibitors of poly (ADP-ribose) polymerase (PARP). In this study we examined the effects of the PARP inhibitor LT626 in combination with ionizing radiation in lung and pancreatic cancers. Our study demonstrated that combination treatment with LT626 and radiation effectively inhibited growth in lung and pancreatic cancer cell lines, better than individual treatment alone. Combination treatment also increased expression of γH2AX and 53BP1 foci and upregulated expression of phosphorylated ATM, ATR and their respective kinases. Using in vivo lung cancer xenograft models we demonstrated that LT626 functioned as an effective radiosensitizer during fractionated radiation treatment, leading to significant decrease in tumor burden and doubling the median survival compared to control group. Overall our in vitro and in vivo studies showed that PARP inhibitor LT626 acted synergistically with radiation in lung and pancreatic cancers.
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Affiliation(s)
- Kedar Hastak
- Department of Medicine, Division of Oncology, Stanford University, Stanford CA 94305, USA
| | - Steven Bhutra
- Department of Biology, Stanford University, Stanford CA 94305, USA.,Current address: Department of Medicine, Advocate Illinois Masonic Medical Center, Chicago, IL 60657, USA
| | - Renate Parry
- Varian Medical Systems, Palo Alto, CA 94306, USA
| | - James M Ford
- Department of Medicine, Division of Oncology, Stanford University, Stanford CA 94305, USA
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5
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Ji L, Liu X, Zhang S, Tang S, Yang S, Li S, Qi X, Yu S, Lu L, Meng X, Liu Z. The Novel Triazolonaphthalimide Derivative LSS-11 Synergizes the Anti-Proliferative Effect of Paclitaxel via STAT3-Dependent MDR1 and MRP1 Downregulation in Chemoresistant Lung Cancer Cells. Molecules 2017; 22:molecules22111822. [PMID: 29072615 PMCID: PMC6150343 DOI: 10.3390/molecules22111822] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 10/15/2017] [Accepted: 10/23/2017] [Indexed: 01/03/2023] Open
Abstract
Multidrug resistance (MDR) is a major cause of the inefficacy and poor response to paclitaxel-based chemotherapy. The combination of conventional cytotoxic drugs has been a plausible strategy for overcoming paclitaxel resistance. Herein, we investigated the cytotoxic effects and underlying mechanism of LSS-11, a novel naphthalimide derivative-based topoisomerase inhibitor, in paclitaxel-resistant A549 (A549/T) lung cancer cells. LSS-11 enhanced cell death in A549/T cells by inducing apoptosis through increasing the DR5 protein level and PARP1 cleavage. Importantly, LSS-11 dose-dependently reduced STAT3 phosphorylation and downregulated its target genes MDR1 and MRP1, without affecting P-gp transport function. Chromatin coimmunoprecipitation (ChIP) assay further revealed that LSS-11 hindered the binding of STAT3 to the MDR1 and MRP1 promoters. Additionally, pharmacological inhibition of p-STAT3 by sulforaphane downregulated MDR1 and MRP1, resulting in A549/T cell death by triggering apoptosis. Collectively, our data show that LSS-11 is a potent naphthalimide-based chemosensitizer that could enhance cell death in paclitaxel-resistant lung cancer cells through the DR5/PARP1 pathway and STAT3/MDR1/MRP1 STAT3 inhibition.
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Affiliation(s)
- Liyan Ji
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- The Postdoctoral Research Station, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Xi Liu
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Shuwei Zhang
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Shunan Tang
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Simin Yang
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Shasha Li
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Xiaoxiao Qi
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Siwang Yu
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Linlin Lu
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
| | - Xiangbao Meng
- Department of Chemical Biology, School of Pharmaceutical Sciences, Peking University, Beijing 100191, China.
| | - Zhongqiu Liu
- International Institute for Translational Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou 510006, China.
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6
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Xu H, Zhou X, Wen X, Lauer FT, Liu KJ, Hudson LG, Aleksunes LM, Burchiel SW. Environmentally Relevant Concentrations of Arsenite Induce Dose-Dependent Differential Genotoxicity Through Poly(ADP-Ribose) Polymerase Inhibition and Oxidative Stress in Mouse Thymus Cells. Toxicol Sci 2015; 149:31-41. [PMID: 26443841 DOI: 10.1093/toxsci/kfv211] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Inhibition of DNA repair and oxidative stress are 2 common mechanisms associated with arsenic-induced genotoxicity. The purpose of this study was to examine mechanisms of genotoxicity induced by environmentally relevant doses of arsenite (As(+3)) in mouse thymus cells. An increase in DNA damage and a decrease in poly(ADP-ribose) polymerase (PARP) activity were seen in vitro following exposure to 50 nM As(+3) in primary mouse thymus cells and a murine thymus pre-T cell line, D1. 3,4-Dihydro-5[4-(1-piperindinyl) butoxyl]-1(2H)-isoquinoline, a well-characterized PARP inhibitor, also produced DNA damage in D1 cells, confirming the correlation between PARP inhibition and DNA damage increase. As(+3) at 500 nM induced double strand breaks (DSBs) in DNA and oxidative stress at 4 h in D1 cells, which was reversed at 18 h. No apoptosis or decrease of viability was observed in these exposures. 4-Hydroxy-2,2,6,6-tetramethylpiperidin-1-oxyl, a widely-used antioxidant, was utilized to confirm that oxidative stress is partially responsible for the increase of strand breaks in 500 nM As(+3) exposure at 4 h. Expression of As(+3) exporters, Mdr1 and Mrp1, were found to be induced by 500 nM As(+3) in D1 cells, suggesting a possible mechanism for reversal of oxidative stress and DSBs at the 18-h timepoint. Finally, we showed that DNA damage and PARP inhibition by As(+3) were reversed by zinc (Zn(+2)) at approximate equimolar doses. Collectively, these results demonstrate that As(+3) at doses within the nanomolar range induce genotoxicity by inhibiting PARP, and produces oxidative stress at higher concentrations, which can be reversed by a Zn(+2) treatment.
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Affiliation(s)
- Huan Xu
- *Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, New Mexico 87131; and
| | - Xixi Zhou
- *Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, New Mexico 87131; and
| | - Xia Wen
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854
| | - Fredine T Lauer
- *Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, New Mexico 87131; and
| | - Ke Jian Liu
- *Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, New Mexico 87131; and
| | - Laurie G Hudson
- *Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, New Mexico 87131; and
| | - Lauren M Aleksunes
- Department of Pharmacology and Toxicology, Ernest Mario School of Pharmacy, Rutgers, the State University of New Jersey, Piscataway, New Jersey 08854
| | - Scott W Burchiel
- *Department of Pharmaceutical Sciences, The University of New Mexico College of Pharmacy, Albuquerque, New Mexico 87131; and
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7
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Luo Q, Li Y, Deng J, Zhang Z. PARP-1 inhibitor sensitizes arsenic trioxide in hepatocellular carcinoma cells via abrogation of G2/M checkpoint and suppression of DNA damage repair. Chem Biol Interact 2014; 226:12-22. [PMID: 25499136 DOI: 10.1016/j.cbi.2014.12.007] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2014] [Revised: 11/16/2014] [Accepted: 12/03/2014] [Indexed: 02/06/2023]
Abstract
Arsenic trioxide (ATO) is successfully used to treat hematological malignancies. However, the clinical application of the agent in solid tumors is largely limited by its dose-dependent toxicity which results from the high intrinsic resistance of the cancer cells. In this study, we firstly identified a series of sensitization effects of 4AN, a PARP-1 inhibitor, on human hepatocellular carcinoma cell line HepG2 to ATO treatment. We showed that treatment of HepG2 cells with 4AN promoted ATO-induced cell death in a synergistic manner. The ATO-sensitization by 4AN was associated with its effect on abrogation of ATO-induced G2/M checkpoint which impairs DNA damage repair and promotes cell apoptosis. Further analysis demonstrated that the ATO-induced G2/M checkpoint was closely related to a decrease in cyclin B1, a key G2/M mediator; whereas 4AN up-regulated the expression of cyclin B1 in ATO-treated cells, which may be at least partly responsible for its effect on abrogation of ATO-induced G2/M checkpoint. This was further supported by the result showing that down-regulation of cyclin B1 using siRNA could restore the G2/M checkpoint in cells co-treated with ATO and 4AN, thereby improving DNA damage repair and decreasing apoptosis. Our study indicates that the abrogation of G2/M checkpoint and the suppression of DNA damage repair contribute to ATO-sensitization by PARP-1 inhibitor in HepG2 cells, which provides a novel insight into the chemo-sensitization mechanism of PARP-1 inhibitor.
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Affiliation(s)
- Qingying Luo
- Department of Environmental Health, West China School of Public Health, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Yang Li
- Department of Environmental Health, West China School of Public Health, Sichuan University, Chengdu, Sichuan, People's Republic of China
| | - Jianjun Deng
- Department of Laboratory, Mianyang 404 Hospital, Mianyang, Sichuan, People's Republic of China
| | - Zunzhen Zhang
- Department of Environmental Health, West China School of Public Health, Sichuan University, Chengdu, Sichuan, People's Republic of China.
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8
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Prasad R, Horton JK, Chastain PD, Gassman NR, Freudenthal BD, Hou EW, Wilson SH. Suicidal cross-linking of PARP-1 to AP site intermediates in cells undergoing base excision repair. Nucleic Acids Res 2014; 42:6337-51. [PMID: 24771347 PMCID: PMC4041460 DOI: 10.1093/nar/gku288] [Citation(s) in RCA: 73] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
Poly(ADP-ribose) polymerase-1 (PARP-1) is an abundant nuclear enzyme in mammalian cells. The enzyme synthesizes polymers of ADP-ribose from the coenzyme NAD+ and plays multifaceted roles in cellular responses to genotoxic stress, including DNA repair. It had been shown that mouse fibroblasts treated with a DNA methylating agent in combination with a PARP inhibitor exhibit higher cytotoxicity than cells treated with methylating agent alone. This lethality of the PARP inhibitor is dependent on apurinic/apyrimidinic (AP) sites in the DNA and the presence of PARP-1. Here, we show that purified PARP-1 is capable of forming a DNA-protein cross-link (DPC) by covalently attaching to the AP site. This DPC formation is specific to the presence of the natural AP site in DNA and is accompanied by a single-strand DNA incision. Cellular studies confirm the formation of PARP-1 DPCs during alkylating agent-induced base excision repair (BER) and formation of DPCs is enhanced by a PARP inhibitor. Using an N-terminal and C-terminal truncated PARP-1 we show that a polypeptide fragment comprising the zinc 3 and BRCT sub-domains is sufficient for DPC formation. The covalent attachment of PARP-1 to AP site-containing DNA appears to be a suicidal event when BER is overwhelmed or disrupted.
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Affiliation(s)
- Rajendra Prasad
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Julie K Horton
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Paul D Chastain
- William Carey University College of Osteopathic Medicine, 498 Tuscan Avenue, Hattiesburg, MS 39401, USA
| | - Natalie R Gassman
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Bret D Freudenthal
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Esther W Hou
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
| | - Samuel H Wilson
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
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9
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Turner RL, Wilkinson JC, Ornelles DA. E1B and E4 oncoproteins of adenovirus antagonize the effect of apoptosis inducing factor. Virology 2014; 456-457:205-19. [PMID: 24889240 DOI: 10.1016/j.virol.2014.03.010] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2014] [Revised: 02/28/2014] [Accepted: 03/10/2014] [Indexed: 01/03/2023]
Abstract
Adenovirus inundates the productively infected cell with linear, double-stranded DNA and an abundance of single-stranded DNA. The cellular response to this stimulus is antagonized by the adenoviral E1B and E4 early genes. A mutant group C adenovirus that fails to express the E1B-55K and E4orf3 genes is unable to suppress the DNA-damage response. Cells infected with this double-mutant virus display significant morphological heterogeneity at late times of infection and frequently contain fragmented nuclei. Nuclear fragmentation was due to the translocation of apoptosis inducing factor (AIF) from the mitochondria into the nucleus. The release of AIF was dependent on active poly(ADP-ribose) polymerase-1 (PARP-1), which appeared to be activated by viral DNA replication. Nuclear fragmentation did not occur in AIF-deficient cells or in cells treated with a PARP-1 inhibitor. The E1B-55K or E4orf3 proteins independently prevented nuclear fragmentation subsequent to PARP-1 activation, possibly by altering the intracellular distribution of PAR-modified proteins.
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Affiliation(s)
- Roberta L Turner
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States
| | - John C Wilkinson
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
| | - David A Ornelles
- Department of Microbiology and Immunology, Wake Forest School of Medicine, Winston-Salem, NC 27157, United States.
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10
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Sousa FG, Matuo R, Soares DG, Escargueil AE, Henriques JAP, Larsen AK, Saffi J. PARPs and the DNA damage response. Carcinogenesis 2012; 33:1433-40. [PMID: 22431722 DOI: 10.1093/carcin/bgs132] [Citation(s) in RCA: 107] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Adenosine diphosphate (ADP)-ribosylation is an important posttranslational modification catalyzed by a variety of enzymes, including poly (ADP ribose) polymerases (PARPs), which use nicotinamide adenine dinucleotide (NAD(+)) as a substrate to synthesize and transfer ADP-ribose units to acceptor proteins. The PARP family members possess a variety of structural domains, span a wide range of functions and localize to various cellular compartments. Among the molecular actions attributed to PARPs, their role in the DNA damage response (DDR) has been widely documented. In particular, PARPs 1-3 are involved in several cellular processes that respond to DNA lesions, which include DNA damage recognition, signaling and repair as well as local transcriptional blockage, chromatin remodeling and cell death induction. However, how these enzymes are able to participate in such numerous and diverse mechanisms in response to DNA damage is not fully understood. Herein, the DDR functions of PARPs 1-3 and the emerging roles of poly (ADP ribose) polymers in DNA damage are reviewed. The development of PARP inhibitors, their applications and mechanisms of action are also discussed in the context of the DDR.
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Affiliation(s)
- Fabricio G Sousa
- Departamento de Biofísica, Centro de Biotecnologia, Universidade Federal do Rio Grande do Sul (UFRGS), Porto Alegre, RS, Brazil
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11
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Kedar PS, Stefanick DF, Horton JK, Wilson SH. Increased PARP-1 association with DNA in alkylation damaged, PARP-inhibited mouse fibroblasts. Mol Cancer Res 2012; 10:360-8. [PMID: 22246237 DOI: 10.1158/1541-7786.mcr-11-0477] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Treatment of base excision repair-proficient mouse fibroblasts with the DNA alkylating agent methyl methanesulfonate (MMS) and a small molecule inhibitor of PARP-1 results in a striking cell killing phenotype, as previously reported. Earlier studies showed that the mechanism of cell death is apoptosis and requires DNA replication, expression of PARP-1, and an intact S-phase checkpoint cell signaling system. It is proposed that activity-inhibited PARP-1 becomes immobilized at DNA repair intermediates, and that this blocks DNA repair and interferes with DNA replication, eventually promoting an S-phase checkpoint and G(2)-M block. Here we report studies designed to evaluate the prediction that inhibited PARP-1 remains DNA associated in cells undergoing repair of alkylation-induced damage. Using chromatin immunoprecipitation with anti-PARP-1 antibody and qPCR for DNA quantification, a higher level of DNA was found associated with PARP-1 in cells treated with MMS plus PARP inhibitor than in cells without inhibitor treatment. These results have implications for explaining the extreme hypersensitivity phenotype after combination treatment with MMS and a PARP inhibitor.
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Affiliation(s)
- Padmini S Kedar
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA
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12
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Nowsheen S, Bonner JA, Yang ES. The poly(ADP-Ribose) polymerase inhibitor ABT-888 reduces radiation-induced nuclear EGFR and augments head and neck tumor response to radiotherapy. Radiother Oncol 2011; 99:331-8. [PMID: 21719137 PMCID: PMC3157293 DOI: 10.1016/j.radonc.2011.05.084] [Citation(s) in RCA: 71] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 05/25/2011] [Accepted: 05/26/2011] [Indexed: 11/22/2022]
Abstract
BACKGROUND AND PURPOSE Current therapies for head and neck cancer frequently are not curative, necessitating novel therapeutic strategies. Thus, we studied whether inhibition of poly(ADP-Ribose) polymerase (PARP), a key DNA repair enzyme, could improve efficacy of radiotherapy in human head and neck cancer. MATERIALS AND METHODS UM-SCC1, UM-SCC5, UM-SCC6, and FaDu human head and neck cancer cellular susceptibility to the PARP inhibitor (PARPi) ABT-888 and/or radiation (IR) was assessed using colony formation assays. DNA damage was evaluated using the alkaline comet assay and immunostaining for γ-H2AX foci. Non-homologous end-joining (NHEJ) mediated repair was measured using phospho-DNA-Pk foci. Epidermal growth factor receptor (EGFR) location was assessed by immunostaining. Poly ADP-Ribose polymerization (PAR) levels were assessed using immunoblotting. RESULTS Human head and neck cancer cells exhibited enhanced cytotoxicity with IR and ABT-888 compared to either agent alone. This increased susceptibility correlated with reduced nuclear EGFR, attenuation of NHEJ, and persistence of DNA damage following IR. Interestingly, a subset of head and neck cancer cells which had elevated basal PAR levels was susceptible to PARPi alone. CONCLUSIONS Combining radiotherapy and PARP inhibition may improve outcomes and quality of life for head and neck cancer patients treated with radiotherapy. Furthermore, this novel strategy may also be feasible in other tumor types. Moreover, PAR levels should be investigated as a potential biomarker for tumor susceptibility to PARP inhibition.
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Affiliation(s)
- Somaira Nowsheen
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine
| | - James A. Bonner
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine
| | - Eddy S. Yang
- Department of Radiation Oncology, University of Alabama at Birmingham School of Medicine
- Department of Cell Biology, University of Alabama at Birmingham School of Medicine
- Department of Pharmacology and Toxicology, and Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine
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Bacalini MG, Di Lonardo D, Catizone A, Ciccarone F, Bruno T, Zampieri M, Guastafierro T, Calabrese R, Fanciulli M, Passananti C, Caiafa P, Reale A. Poly(ADP-ribosyl)ation affects stabilization of Che-1 protein in response to DNA damage. DNA Repair (Amst) 2011; 10:380-9. [PMID: 21317046 DOI: 10.1016/j.dnarep.2011.01.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Revised: 12/29/2010] [Accepted: 01/04/2011] [Indexed: 12/18/2022]
Abstract
Poly(ADP-ribose) polymerase 1 (PARP-1) catalyzes a post-translational modification that plays a crucial role in coordinating the signalling cascade in response to stress stimuli. During the DNA damage response, phosphorylation by ataxia telangiectasia mutated (ATM) kinase and checkpoint kinase Chk2 induces the stabilization of Che-1 protein, which is critical for the maintenance of G2/M arrest. In this study we showed that poly(ADP-ribosyl)ation, beyond phosphorylation, is involved in the regulation of Che-1 stabilization following DNA damage. We demonstrated that Che-1 accumulation upon doxorubicin treatment is reduced after the inhibition of PARP activity in HCT116 cells and in PARP-1 knock-out or silenced cells. In accordance, impairment in Che-1 accumulation by PARP inhibition reduced Che-1 occupancy at p21 promoter and affected the expression of the corresponding gene. Epistasis experiments showed that the effect of poly(ADP-ribosyl)ation on Che-1 stabilization is independent from ATM kinase activity. Indeed we demonstrated that Che-1 protein co-immunoprecipitates with ADP-ribose polymers and that PARP-1 directly interacts with Che-1, promoting its modification in vitro and in vivo.
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Affiliation(s)
- Maria Giulia Bacalini
- Department of Cellular Biotechnologies and Haematology, Section of Clinical Biochemistry, Sapienza University of Rome, Viale Regina Elena 324, 00161 Rome, Italy
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14
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Horton JK, Stefanick DF, Zeng JY, Carrozza MJ, Wilson SH. Requirement for NBS1 in the S phase checkpoint response to DNA methylation combined with PARP inhibition. DNA Repair (Amst) 2010; 10:225-34. [PMID: 21130714 DOI: 10.1016/j.dnarep.2010.11.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 11/03/2010] [Accepted: 11/08/2010] [Indexed: 11/19/2022]
Abstract
Treatment of PARP-1-expressing cells with the combination of a DNA methylating agent (MMS) and the PARP inhibitor 4-amino-1,8-naphthalimide (4-AN) leads to an ATR/Chk1-dependent S phase checkpoint and cell death by apoptosis. Activation of ATM/Chk2 is involved in sustaining the S phase checkpoint, and double strand break (DSB) accumulation was demonstrated. NBS1, part of the MRN complex that responds to DSBs, is known to modulate ATR- and ATM-dependent checkpoint responses to UV and IR, but a role in the response to PARP inhibition has not been addressed. Here we show that the S phase checkpoint observed 4-8h after MMS+4-AN treatment was absent in cells deficient in NBS1, but was present in NBS1-complemented (i.e., functionally wild-type) cells, indicating a critical role for NBS1 in this checkpoint response. NBS1 was phosphorylated in response to MMS+4-AN treatment, and this was partially ATR- and ATM-dependent, suggesting involvement of both upstream kinases. NBS1 expression had little effect on ATR-mediated phosphorylation of Chk1 and ATM-mediated phosphorylation of Chk2 in response to MMS+4-AN. Phosphorylation of SMC1 was also observed in response to MMS+4-AN treatment. In the absence of ATM and NBS1, phosphorylation of SMC1 was weak, especially at early times after MMS+4-AN treatment. In the absence of ATR activation, reduced SMC1 phosphorylation was seen over a 24h time course. These results suggested that both ATR and ATM phosphorylate SMC1 in response to MMS+4-AN and that this phosphorylation is enhanced by phospho-NBS1. The loss of the MMS+4-AN-induced S phase checkpoint in NBS1-deficient cells may be due to a reduced cellular level of the critical downstream effector, phospho-SMC1.
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Affiliation(s)
- Julie K Horton
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
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15
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Wilson SH, Beard WA, Shock DD, Batra VK, Cavanaugh NA, Prasad R, Hou EW, Liu Y, Asagoshi K, Horton JK, Stefanick DF, Kedar PS, Carrozza MJ, Masaoka A, Heacock ML. Base excision repair and design of small molecule inhibitors of human DNA polymerase β. Cell Mol Life Sci 2010; 67:3633-47. [PMID: 20844920 PMCID: PMC3324036 DOI: 10.1007/s00018-010-0489-1] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2010] [Accepted: 07/28/2010] [Indexed: 10/19/2022]
Abstract
Base excision repair (BER) can protect a cell after endogenous or exogenous genotoxic stress, and a deficiency in BER can render a cell hypersensitive to stress-induced apoptotic and necrotic cell death, mutagenesis, and chromosomal rearrangements. However, understanding of the mammalian BER system is not yet complete as it is extraordinarily complex and has many back-up processes that complement a deficiency in any one step. Due of this lack of information, we are unable to make accurate predictions on therapeutic approaches targeting BER. A deeper understanding of BER will eventually allow us to conduct more meaningful clinical interventions. In this review, we will cover historical and recent information on mammalian BER and DNA polymerase β and discuss approaches toward development and use of small molecule inhibitors to manipulate BER. With apologies to others, we will emphasize results obtained in our laboratory and those of our collaborators.
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Affiliation(s)
- Samuel H Wilson
- Laboratory of Structural Biology, National Institute of Environmental Health Sciences, NIH, 111 T.W. Alexander Drive, Research Triangle Park, NC 27709, USA.
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16
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Heacock ML, Stefanick DF, Horton JK, Wilson SH. Alkylation DNA damage in combination with PARP inhibition results in formation of S-phase-dependent double-strand breaks. DNA Repair (Amst) 2010; 9:929-36. [PMID: 20573551 DOI: 10.1016/j.dnarep.2010.05.007] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2010] [Revised: 05/05/2010] [Accepted: 05/24/2010] [Indexed: 02/06/2023]
Abstract
The combination of poly(ADP-ribose)polymerase (PARP) inhibitors and alkylating agents is currently being investigated in cancer therapy clinical trials. However, the DNA lesions producing the synergistic cell killing effect in tumors are not fully understood. Treatment of human and mouse fibroblasts with the monofunctional DNA methylating agent methyl methanesulfonate (MMS) in the presence of a PARP inhibitor has been shown to trigger a cell cycle checkpoint response. Among other changes, this DNA damage response to combination treatment includes activation of ATM/Chk2 and phosphorylation of histone H2A.X. These changes are consistent with DNA double-strand break (DSB) formation during the response, but the measurement of DSBs has not been addressed. Such DSB evaluation is important in understanding this DNA damage response because events other than DSB formation are known to lead to ATM/Chk2 activation and H2A.X phosphorylation. Here, we examined the structural integrity of genomic DNA after the combined treatment of cells with MMS and a PARP inhibitor, i.e., exposure to a sub-lethal dose of MMS in the presence of the PARP inhibitor 4-amino-1,8-napthalimide (4-AN). We used pulsed field gel electrophoresis (PFGE) for measurement of DSBs in both human and mouse embryonic fibroblasts, and flow cytometry to follow the phosphorylated form of H2A.X (gamma-H2A.X). The results indicate that DSBs are formed with the combination treatment, but not following treatment with either agent alone. Our data also show that formation of gamma-H2A.X correlates with PARP-1-expressing cells in S-phase of the cell cycle. The observations support the model that persistence of PARP-1 at base excision repair intermediates, as cells move into S-phase, leads to DSBs and the attendant checkpoint responses.
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Affiliation(s)
- Michelle L Heacock
- Laboratory of Structural Biology, NIEHS, National Institutes of Health, Research Triangle Park, NC 27709, USA
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