1
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A rapid multiplex cell-free assay on biochip to evaluate functional aspects of double-strand break repair. Sci Rep 2022; 12:20054. [PMID: 36414637 PMCID: PMC9681732 DOI: 10.1038/s41598-022-23819-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 11/07/2022] [Indexed: 11/24/2022] Open
Abstract
The repair of DNA double-strand breaks (DSBs) involves interdependent molecular pathways, of which the choice is crucial for a cell's fate when facing a damage. Growing evidence points toward the fact that DSB repair capacities correlate with disease aggressiveness, treatment response and treatment-related toxicities in cancer. Scientific and medical communities need more easy-to-use and efficient tools to rapidly estimate DSB repair capacities from a tissue, enable routine-accessible treatment personalization, and hopefully, improve survival. Here, we propose a new functional biochip assay (NEXT-SPOT) that characterizes DSB repair-engaged cellular pathways and provides qualitative and quantitative information on the contribution of several pathways in less than 2 h, from 10 mg of cell lysates. We introduce the NEXT-SPOT technology, detail the molecular characterizations of different repair steps occurring on the biochip, and show examples of DSB repair profiling using three cancer cell lines treated or not with a DSB-inducer (doxorubicin) and/or a DNA repair inhibitor (RAD51 inhibitor; DNA-PK inhibitor; PARP inhibitor). Among others, we demonstrate that NEXT-SPOT can accurately detect decreased activities in strand invasion and end-joining mechanisms following DNA-PK or RAD51 inhibition in DNA-PK-proficient cell lines. This approach offers an all-in-one reliable strategy to consider DSB repair capacities as predictive biomarkers easily translatable to the clinic.
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2
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Chan YL, Zhang A, Weissman BP, Bishop DK. RPA resolves conflicting activities of accessory proteins during reconstitution of Dmc1-mediated meiotic recombination. Nucleic Acids Res 2019; 47:747-761. [PMID: 30462332 PMCID: PMC6344864 DOI: 10.1093/nar/gky1160] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/01/2018] [Indexed: 01/22/2023] Open
Abstract
Dmc1 catalyzes homology search and strand exchange during meiotic recombination in budding yeast and many other organisms including humans. Here we reconstitute Dmc1 recombination in vitro using six purified proteins from budding yeast including Dmc1 and its accessory proteins RPA, Rad51, Rdh54/Tid1, Mei5-Sae3 and Hop2-Mnd1 to promote D-loop formation between ssDNA and dsDNA substrates. Each accessory protein contributed to Dmc1’s activity, with the combination of all six proteins yielding optimal activity. The ssDNA binding protein RPA plays multiple roles in stimulating Dmc1’s activity including by overcoming inhibitory effects of ssDNA secondary structure on D-loop reactions, and by elongating D-loops. In addition, we demonstrate that RPA limits inhibitory interactions of Hop2-Mnd1 and Rdh54/Tid1 that otherwise occur during assembly of Dmc1-ssDNA nucleoprotein filaments. Finally, we report interactions between the proteins employed in the biochemical reconstitution including a direct interaction between Rad51 and Dmc1 that is enhanced by Mei5-Sae3.
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Affiliation(s)
- Yuen-Ling Chan
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA
| | - Annie Zhang
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA.,Department of Biology, Massachusetts Institute of Technology, Cambridge, MA, USA
| | | | - Douglas K Bishop
- Department of Radiation and Cellular Oncology, University of Chicago, Chicago, IL, USA.,Department of Molecular Genetics and Cell Biology, University of Chicago, Chicago, IL, USA
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3
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Bylicky MA, Mueller GP, Day RM. Radiation resistance of normal human astrocytes: the role of non-homologous end joining DNA repair activity. JOURNAL OF RADIATION RESEARCH 2019; 60:37-50. [PMID: 30423138 PMCID: PMC6373697 DOI: 10.1093/jrr/rry084] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 08/03/2018] [Indexed: 05/27/2023]
Abstract
Radiotherapy is a common modality for treatment of brain cancers, but it can induce long-term physiological and cognitive deficits. The responses of normal human brain cells to radiation is not well understood. Astrocytes have been shown to have a variety of protective mechanisms against oxidative stress and have been shown to protect neurons. We investigated the response of cultured normal human astrocytes (NHAs) to X-ray irradiation. Following exposure to 10 Gy X-irradiation, NHAs exhibited DNA damage as indicated by the formation of γ-H2AX foci. Western blotting showed that NHAs displayed a robust increase in expression of non-homologous end joining DNA repair enzymes within 15 min post-irradiation and increased expression of homologous recombination DNA repair enzymes ~2 h post-irradiation. The cell cycle checkpoint protein p21/waf1 was upregulated from 6-24 h, and then returned to baseline. Levels of DNA repair enzymes returned to basal ~48 h post-irradiation. NHAs re-entered the cell cycle and proliferation was observed at 6 days. In contrast, normal human mesenchymal stem cells (MSCs) failed to upregulate DNA repair enzymes and instead displayed sustained upregulation of p21/waf1, a cell cycle checkpoint marker for senescence. Ectopic overexpression of Ku70 was sufficient to protect MSCs from sustained upregulation of p21/waf1 induced by 10 Gy X-rays. These findings suggest that increased expression of Ku70 may be a key mechanism for the radioresistance of NHAs, preventing their accelerated senescence from high-dose radiation. These results may have implications for the development of novel targets for radiation countermeasure development.
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Affiliation(s)
- Michelle A Bylicky
- Department of Anatomy, Physiology, and Genetics, The Uniformed Services University of the Health Sciences, Jones Bridge Road, Bethesda, MD, USA
| | - Gregory P Mueller
- Department of Anatomy, Physiology, and Genetics, The Uniformed Services University of the Health Sciences, Jones Bridge Road, Bethesda, MD, USA
| | - Regina M Day
- Department of Pharmacology and Molecular Therapeutics, The Uniformed Services University of the Health Sciences, Jones Bridge Road, Bethesda, MD, USA
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4
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Gataulin DV, Carey JN, Li J, Shah P, Grubb JT, Bishop DK. The ATPase activity of E. coli RecA prevents accumulation of toxic complexes formed by erroneous binding to undamaged double stranded DNA. Nucleic Acids Res 2018; 46:9510-9523. [PMID: 30137528 PMCID: PMC6182174 DOI: 10.1093/nar/gky748] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Revised: 08/01/2018] [Accepted: 08/06/2018] [Indexed: 01/01/2023] Open
Abstract
The Escherichia coli RecA protein catalyzes the central step of homologous recombination using its homology search and strand exchange activity. RecA is a DNA-dependent ATPase, but its homology search and strand exchange activities are largely independent of its ATPase activity. ATP hydrolysis converts a high affinity DNA binding form, RecA-ATP, to a low affinity form RecA-ADP, thereby supporting an ATP hydrolysis-dependent dynamic cycle of DNA binding and dissociation. We provide evidence for a novel function of RecA's dynamic behavior; RecA's ATPase activity prevents accumulation of toxic complexes caused by direct binding of RecA to undamaged regions of dsDNA. We show that a mutant form of RecA, RecA-K250N, previously shown to be toxic to E. coli, is a loss-of-function ATPase-defective mutant. We use a new method for detecting RecA complexes involving nucleoid surface spreading and immunostaining. The method allows detection of damage-induced RecA foci; STED microscopy revealed these to typically be between 50 and 200 nm in length. RecA-K250N, and other toxic variants of RecA, form spontaneous DNA-bound complexes that are independent of replication and of accessory proteins required to load RecA onto tracts of ssDNA in vivo, supporting the hypothesis that RecA's expenditure of ATP serves an error correction function.
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Affiliation(s)
- Daniil V Gataulin
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
| | - Jeffrey N Carey
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
| | - Junya Li
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
| | - Parisha Shah
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
| | - Jennifer T Grubb
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
| | - Douglas K Bishop
- Department of Radiation and Cellular Oncology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
- Department of Molecular Genetics and Cell Biology, University of Chicago, Cummings Life Science Center, 920 East 58th Street, Chicago, IL 60615, USA
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5
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Ledda C, Loreto C, Zammit C, Marconi A, Fago L, Matera S, Costanzo V, Sanzà GF, Palmucci S, Ferrante M, Costa C, Fenga C, Biondi A, Pomara C, Rapisarda V. Non‑infective occupational risk factors for hepatocellular carcinoma: A review (Review). Mol Med Rep 2017; 15:511-533. [PMID: 28000892 PMCID: PMC5364850 DOI: 10.3892/mmr.2016.6046] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2015] [Accepted: 07/01/2016] [Indexed: 02/07/2023] Open
Abstract
Liver cancer is the second leading worldwide cause of cancer‑associated mortalities. Hepatocellular carcinoma, which accounts for the majority of liver tumors, ranks fifth among types of human cancer. Well‑established risk factors for liver cancer include the hepatitis B and C viruses, aflatoxins, alcohol consumption, and oral contraceptives. Tobacco smoking, androgenic steroids, and diabetes mellitus are suspected risk factors. Current knowledge regarding non‑infective occupational risk factors for liver cancer is inconclusive. The relevance of liver disorders to occupational medicine lies in the fact that the majority of chemicals are metabolized in the liver, and toxic metabolites generated via metabolism are the predominant cause of liver damage. However, their non‑specific clinical manifestations that are similar in a number of liver diseases make diagnosis difficult. Furthermore, concomitant conditions, such as viral hepatitis and alcohol or drug abuse, may mask liver disorders that result from occupational hepatotoxic agents and block the demonstration of an occupational cause. The identification of environmental agents that result in human cancer is a long and often difficult process. The purpose of the present review is to summarize current knowledge regarding the association of non‑infective occupational risk exposure and HCC, to encourage further research and draw attention to this global occupational public health problem.
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Affiliation(s)
- Caterina Ledda
- Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
- Hygiene and Public Health, Department of Medical Sciences, Surgical and Advanced Technologies ‘GF Ingrassia’, University of Catania, I-95123 Catania, Italy
| | - Carla Loreto
- Human Anatomy and Histology, Department of Biomedical and Biotechnology Sciences, University of Catania, I-95123 Catania, Italy
| | - Christian Zammit
- Anatomy Department, Faculty of Medicine and Surgery, University of Malta, MSD-2080 Msida, Malta
| | - Andrea Marconi
- Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
| | - Lucrezia Fago
- Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
| | - Serena Matera
- Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
| | - Valentina Costanzo
- Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
| | - Giovanni Fuccio Sanzà
- Division of Radiology, ‘Policlinico-Vittorio Emanuele’ University Hospital, University of Catania, I-95123 Catania, Italy
| | - Stefano Palmucci
- Division of Radiology, ‘Policlinico-Vittorio Emanuele’ University Hospital, University of Catania, I-95123 Catania, Italy
| | - Margherita Ferrante
- Hygiene and Public Health, Department of Medical Sciences, Surgical and Advanced Technologies ‘GF Ingrassia’, University of Catania, I-95123 Catania, Italy
| | - Chiara Costa
- Occupational Medicine, Department of the Environment, Safety, Territory, Food and Health Sciences, University of Messina, I-98125 Messina, Italy
| | - Concettina Fenga
- Occupational Medicine, Department of the Environment, Safety, Territory, Food and Health Sciences, University of Messina, I-98125 Messina, Italy
| | - Antonio Biondi
- General Surgery, Department of General Surgery and Medical-Surgical Specialties, University of Catania, I-95123 Catania, Italy
| | - Cristoforo Pomara
- Anatomy Department, Faculty of Medicine and Surgery, University of Malta, MSD-2080 Msida, Malta
- Forensic Pathology, Department of Clinical and Experimental Medicine, University of Foggia, I-71122 Foggia, Italy
| | - Venerando Rapisarda
- Occupational Medicine, Department of Clinical and Experimental Medicine, University of Catania, I-95123 Catania, Italy
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6
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Budke B, Lv W, Kozikowski AP, Connell PP. Recent Developments Using Small Molecules to Target RAD51: How to Best Modulate RAD51 for Anticancer Therapy? ChemMedChem 2016; 11:2468-2473. [PMID: 27781374 DOI: 10.1002/cmdc.201600426] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2016] [Indexed: 11/11/2022]
Abstract
Homologous recombination (HR) is an evolutionarily conserved DNA repair process. Overexpression of the key HR protein RAD51 is a common feature of malignant cells. RAD51 plays two distinct genome-stabilizing roles, including HR-mediated repair of double-strand breaks (DSBs) and the promotion of replication fork stability during replication stress. Because upregulation of RAD51 in cancer cells can promote tumor resistance to DNA-damaging oncologic therapies, we and others have worked to develop cancer therapeutics that target various aspects of RAD51 protein function. Herein, we provide an overview of recent developments in this field, together with our perspectives on the challenges associated with these evolving anticancer strategies.
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Affiliation(s)
- Brian Budke
- Department of Radiation and Cellular Oncology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL, 60637, USA
| | - Wei Lv
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Alan P Kozikowski
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago, 833 S. Wood Street, Chicago, IL, 60612, USA
| | - Philip P Connell
- Department of Radiation and Cellular Oncology, University of Chicago, 5841 S. Maryland Ave., Chicago, IL, 60637, USA
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7
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Lv W, Budke B, Pawlowski M, Connell PP, Kozikowski AP. Development of Small Molecules that Specifically Inhibit the D-loop Activity of RAD51. J Med Chem 2016; 59:4511-25. [PMID: 27049177 DOI: 10.1021/acs.jmedchem.5b01762] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
RAD51 is the central protein in homologous recombination (HR) DNA repair and represents a therapeutic target in oncology. Herein we report a novel class of RAD51 inhibitors that were identified by high throughput screening. In contrast to many previously reported RAD51 inhibitors, our lead compound 1 is capable of blocking RAD51-mediated D-loop formation (IC50 21.3 ± 7.8 μM) at concentrations that do not influence RAD51 binding to ssDNA. In human cells, 1 inhibits HR (IC50 13.1 ± 1.6 μM) without blocking RAD51's ability to assemble into subnuclear foci at sites of DNA damage. We determined that the active constituent of 1 is actually an oxidized derivative (termed RI(dl)-1 or 8) of the original screening compound. Our SAR campaign also yielded RI(dl)-2 (hereafter termed 9h), which effectively blocks RAD51's D-loop activity in biochemical systems (IC50 11.1 ± 1.3 μM) and inhibits HR activity in human cells (IC50 3.0 ± 1.8 μM).
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Affiliation(s)
- Wei Lv
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago , Chicago, 833 South Wood Street 539c PHAR, MC 781, Illinois 60612, United States
| | - Brian Budke
- Department of Radiation and Cellular Oncology, University of Chicago , Chicago, Illinois 60637, United States
| | - Michal Pawlowski
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago , Chicago, 833 South Wood Street 539c PHAR, MC 781, Illinois 60612, United States
| | - Philip P Connell
- Department of Radiation and Cellular Oncology, University of Chicago , Chicago, Illinois 60637, United States
| | - Alan P Kozikowski
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago , Chicago, 833 South Wood Street 539c PHAR, MC 781, Illinois 60612, United States
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8
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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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9
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RECQL5 has unique strand annealing properties relative to the other human RecQ helicase proteins. DNA Repair (Amst) 2015; 37:53-66. [PMID: 26717024 DOI: 10.1016/j.dnarep.2015.11.005] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 11/21/2015] [Accepted: 11/24/2015] [Indexed: 11/24/2022]
Abstract
The RecQ helicases play important roles in genome maintenance and DNA metabolism (replication, recombination, repair, and transcription). Five different homologs are present in humans, three of which are implicated in accelerated aging genetic disorders: Rothmund Thomson (RECQL4), Werner (WRN), and Bloom (BLM) syndromes. While the DNA helicase activities of the 5 human RecQ helicases have been extensively characterized, much less is known about their DNA double strand annealing activities. Strand annealing is an important integral enzymatic activity in DNA metabolism, including DNA repair. Here, we have characterized the strand annealing activities of all five human RecQ helicase proteins and compared them. Interestingly, the relative strand annealing activities of the five RecQ proteins are not directly (inversely) related to their helicase activities. RECQL5 possesses relatively strong annealing activity on long or small duplexed substrates compared to the other RecQs. Additionally, the strand annealing activity of RECQL5 is not inhibited by the presence of ATP, unlike the other RecQs. We also show that RECQL5 efficiently catalyzes annealing of RNA to DNA in vitro in the presence or absence of ATP, revealing a possible new function for RECQL5. Additionally, we investigate how different known RecQ interacting proteins, RPA, Ku, FEN1 and RAD51, regulate their strand annealing activity. Collectively, we find that the human RecQ proteins possess differential DNA double strand annealing activities and we speculate on their individual roles in DNA repair. This insight is important in view of the many cellular DNA metabolic actions of the RecQ proteins and elucidates their unique functions in the cell.
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10
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Trichloroethylene-induced gene expression and DNA methylation changes in B6C3F1 mouse liver. PLoS One 2014; 9:e116179. [PMID: 25549359 PMCID: PMC4280179 DOI: 10.1371/journal.pone.0116179] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/03/2014] [Indexed: 12/31/2022] Open
Abstract
Trichloroethylene (TCE), widely used as an organic solvent in the industry, is a common contaminant in air, soil, and water. Chronic TCE exposure induced hepatocellular carcinoma in mice, and occupational exposure in humans was suggested to be associated with liver cancer. To understand the role of non-genotoxic mechanism(s) for TCE action, we examined the gene expression and DNA methylation changes in the liver of B6C3F1 mice orally administered with TCE (0, 100, 500 and 1000 mg/kg b.w. per day) for 5 days. After 5 days TCE treatment at a dose level of 1000 mg/kg b.w., a total of 431 differentially expressed genes were identified in mouse liver by microarray, of which 291 were up-regulated and 140 down-regulated. The expression changed genes were involved in key signal pathways including PPAR, proliferation, apoptosis and homologous recombination. Notably, the expression level of a number of vital genes involved in the regulation of DNA methylation, such as Utrf1, Tet2, DNMT1, DNMT3a and DNMT3b, were dysregulated. Although global DNA methylation change was not detected in the liver of mice exposed to TCE, the promoter regions of Cdkn1a and Ihh were found to be hypo- and hypermethylated respectively, which correlated negatively with their mRNA expression changes. Furthermore, the gene expression and DNA methylation changes induced by TCE were dose dependent. The overall data indicate that TCE exposure leads to aberrant DNA methylation changes, which might alter the expression of genes involved in the TCE-induced liver tumorgenesis.
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11
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Jiang Y, Chen J, Tong J, Chen T. Trichloroethylene-induced gene expression and DNA methylation changes in B6C3F1 mouse liver. PLoS One 2014. [PMID: 25549359 DOI: 10.1371/-journal.pone.0116179] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Trichloroethylene (TCE), widely used as an organic solvent in the industry, is a common contaminant in air, soil, and water. Chronic TCE exposure induced hepatocellular carcinoma in mice, and occupational exposure in humans was suggested to be associated with liver cancer. To understand the role of non-genotoxic mechanism(s) for TCE action, we examined the gene expression and DNA methylation changes in the liver of B6C3F1 mice orally administered with TCE (0, 100, 500 and 1000 mg/kg b.w. per day) for 5 days. After 5 days TCE treatment at a dose level of 1000 mg/kg b.w., a total of 431 differentially expressed genes were identified in mouse liver by microarray, of which 291 were up-regulated and 140 down-regulated. The expression changed genes were involved in key signal pathways including PPAR, proliferation, apoptosis and homologous recombination. Notably, the expression level of a number of vital genes involved in the regulation of DNA methylation, such as Utrf1, Tet2, DNMT1, DNMT3a and DNMT3b, were dysregulated. Although global DNA methylation change was not detected in the liver of mice exposed to TCE, the promoter regions of Cdkn1a and Ihh were found to be hypo- and hypermethylated respectively, which correlated negatively with their mRNA expression changes. Furthermore, the gene expression and DNA methylation changes induced by TCE were dose dependent. The overall data indicate that TCE exposure leads to aberrant DNA methylation changes, which might alter the expression of genes involved in the TCE-induced liver tumorgenesis.
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Affiliation(s)
- Yan Jiang
- Department of Physiology, School of Biology and Basic Medical Sciences, Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, China
| | - Jiahong Chen
- Department of Toxicology, School of Public Health, Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, China
| | - Jian Tong
- Department of Toxicology, School of Public Health, Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, China
| | - Tao Chen
- Department of Toxicology, School of Public Health, Soochow University, Suzhou, China; Jiangsu Key Laboratory of Preventive and Translational Medicine for Geriatric Diseases, Soochow University, Suzhou, China
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12
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Mason JM, Logan HL, Budke B, Wu M, Pawlowski M, Weichselbaum RR, Kozikowski AP, Bishop DK, Connell PP. The RAD51-stimulatory compound RS-1 can exploit the RAD51 overexpression that exists in cancer cells and tumors. Cancer Res 2014; 74:3546-55. [PMID: 24753542 DOI: 10.1158/0008-5472.can-13-3220] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RAD51 is the central protein that catalyzes DNA repair via homologous recombination, a process that ensures genomic stability. RAD51 protein is commonly expressed at high levels in cancer cells relative to their noncancerous precursors. High levels of RAD51 expression can lead to the formation of genotoxic RAD51 protein complexes on undamaged chromatin. We developed a therapeutic approach that exploits this potentially toxic feature of malignancy, using compounds that stimulate the DNA-binding activity of RAD51 to promote cancer cell death. A panel of immortalized cell lines was challenged with the RAD51-stimulatory compound RS-1. Resistance to RS-1 tended to occur in cells with higher levels of RAD54L and RAD54B, which are Swi2/Snf2-related translocases known to dissociate RAD51 filaments from dsDNA. In PC3 prostate cancer cells, RS-1-induced lethality was accompanied by the formation of microscopically visible RAD51 nuclear protein foci occurring in the absence of any DNA-damaging treatment. Treatment with RS-1 promoted significant antitumor responses in a mouse model, providing proof-of-principle for this novel therapeutic strategy.
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Affiliation(s)
- Jennifer M Mason
- Authors' Affiliations: Department of Radiation and Cellular Oncology
| | - Hillary L Logan
- Authors' Affiliations: Department of Radiation and Cellular Oncology
| | - Brian Budke
- Authors' Affiliations: Department of Radiation and Cellular Oncology
| | - Megan Wu
- Authors' Affiliations: Department of Radiation and Cellular Oncology
| | - Michal Pawlowski
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago, Chicago, Illinois
| | - Ralph R Weichselbaum
- Authors' Affiliations: Department of Radiation and Cellular Oncology, Ludwig Center for Metastasis Research
| | - Alan P Kozikowski
- Department of Medicinal Chemistry and Pharmacognosy, Drug Discovery Program, University of Illinois at Chicago, Chicago, Illinois
| | - Douglas K Bishop
- Authors' Affiliations: Department of Radiation and Cellular Oncology, Department of Molecular Genetics and Cell Biology, University of Chicago; and
| | - Philip P Connell
- Authors' Affiliations: Department of Radiation and Cellular Oncology,
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13
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Wu HY, Li HW. Crowding alters the dynamics and the length of RecA nucleoprotein filaments in RecA-mediated strand exchange. Chemphyschem 2013; 15:80-4. [PMID: 24281991 DOI: 10.1002/cphc.201300835] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2013] [Revised: 10/24/2013] [Indexed: 11/10/2022]
Abstract
Crowd impact: Molecular crowding effects of bovine serum albumin and poly(ethylene glycol) on the Escherichia coli RecA-mediated strand exchange reaction are quantified by using a single-molecule outgoing strand experiment and magnetic pull-down and ATPase assays. The alterations of the biochemical parameters of this complex enzymatic reaction in such crowded environments are discussed.
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Affiliation(s)
- Hung-Yi Wu
- Department of Chemistry, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei, 10617 Taiwan (R.O.C). Fax: (+886) 2-2363-6359
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