151
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Weng SH, Tsai MS, Chiu YF, Kuo YH, Chen HJ, Lin YW. Enhancement of Mitomycin C-Induced Cytotoxicity by Curcumin Results from Down-Regulation of MKK1/2-ERK1/2-Mediated Thymidine Phosphorylase Expression. Basic Clin Pharmacol Toxicol 2011; 110:298-306. [DOI: 10.1111/j.1742-7843.2011.00806.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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152
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Yue J, Lu H, Liu J, Berwick M, Shen Z. Filamin-A as a marker and target for DNA damage based cancer therapy. DNA Repair (Amst) 2011; 11:192-200. [PMID: 22051193 DOI: 10.1016/j.dnarep.2011.10.019] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022]
Abstract
Filamin-A, also called actin binding protein 280 (ABP-280), cross-links the actin filaments into dynamic orthogonal network to serve as scaffolds in multiple signaling pathways. It has been reported that filamin-A interacts with DNA damage response proteins BRCA1 and BRCA2. Defects of filamin-A impair the repair of DNA double strand breaks (DSBs), resulting in sensitization of cells to ionizing radiation. In this study, we sought to test the hypothesis that filamin-A can be used as a target for cancer chemotherapy and as a biomarker to predict cancer response to therapeutic DNA damage. We found that reduction of filamin-A sensitizes cancer cells to chemotherapy reagents bleomycin and cisplatin, delays the repair of not only DSBs but also single strand breaks (SSBs) and interstrand crosslinks (ICLs), and increases chromosome breaks after the drug treatment. By treating a panel of human melanoma cell lines with variable filamin-A expression, we observed a correlation between expression level of filamin-A protein and drug IC(50). We further inhibited the expression of filamin-A in melanoma cells, and found that this confers an increased sensitivity to bleomycin and cisplatin treatment in a mouse xenograft tumor model. These results suggest that filamin-A plays a role in repair of a variety of DNA damage, that lack of filamin-A is a prognostic marker for a better outcome after DNA damage based treatment, and filamin-A can be inhibited to sensitize filamin-A positive cancer cells to therapeutic DNA damage. Thus filamin-A can be used as a biomarker and a target for DNA damage based cancer therapy.
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Affiliation(s)
- Jingyin Yue
- Department of Radiation Oncology, The Cancer Institute of New Jersey, UMDNJ-Robert Wood Johnson Medical School, 195 Little Albany St., New Brunswick, NJ 08903, USA
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153
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Global phosphoproteome profiling reveals unanticipated networks responsive to cisplatin treatment of embryonic stem cells. Mol Cell Biol 2011; 31:4964-77. [PMID: 22006019 DOI: 10.1128/mcb.05258-11] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cellular responses to DNA-damaging agents involve the activation of various DNA damage signaling and transduction pathways. Using quantitative and high-resolution tandem mass spectrometry, we determined global changes in protein level and phosphorylation site profiles following treatment of SILAC (stable isotope labeling by amino acids in cell culture)-labeled murine embryonic stem cells with the anticancer drug cisplatin. Network and pathway analyses indicated that processes related to the DNA damage response and cytoskeleton organization were significantly affected. Although the ATM (ataxia telangiectasia mutated) and ATR (ATM and Rad3-related) consensus sequence (S/T-Q motif) was significantly overrepresented among hyperphosphorylated peptides, about half of the >2-fold-upregulated phosphorylation sites based on the consensus sequence were not direct substrates of ATM and ATR. Eleven protein kinases mainly belonging to the mitogen-activated protein kinase (MAPK) family were identified as being regulated in their kinase domain activation loop. The biological importance of three of these kinases (cyclin-dependent kinase 7 [CDK7], Plk1, and KPCD1) in the protection against cisplatin-induced cytotoxicity was demonstrated by small interfering RNA (siRNA)-mediated knockdown. Our results indicate that the cellular response to cisplatin involves a variety of kinases and phosphatases not only acting in the nucleus but also regulating cytoplasmic targets, resulting in extensive cytoskeletal rearrangements. Integration of transcriptomic and proteomic data revealed a poor correlation between changes in the relative levels of transcripts and their corresponding proteins, but a large overlap in affected pathways at the levels of mRNA, protein, and phosphoprotein. This study provides an integrated view of pathways activated by genotoxic stress and deciphers kinases that play a pivotal role in regulating cellular processes other than the DNA damage response.
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154
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Klocko AD, Schroeder JW, Walsh BW, Lenhart JS, Evans ML, Simmons LA. Mismatch repair causes the dynamic release of an essential DNA polymerase from the replication fork. Mol Microbiol 2011; 82:648-63. [PMID: 21958350 DOI: 10.1111/j.1365-2958.2011.07841.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Mismatch repair (MMR) corrects DNA polymerase errors occurring during genome replication. MMR is critical for genome maintenance, and its loss increases mutation rates several hundred fold. Recent work has shown that the interaction between the mismatch recognition protein MutS and the replication processivity clamp is important for MMR in Bacillus subtilis. To further understand how MMR is coupled to DNA replication, we examined the subcellular localization of MMR and DNA replication proteins fused to green fluorescent protein (GFP) in live cells, following an increase in DNA replication errors. We demonstrate that foci of the essential DNA polymerase DnaE-GFP decrease following mismatch incorporation and that loss of DnaE-GFP foci requires MutS. Furthermore, we show that MutS and MutL bind DnaE in vitro, suggesting that DnaE is coupled to repair. We also found that DnaE-GFP foci decrease in vivo following a DNA damage-independent arrest of DNA synthesis showing that loss of DnaE-GFP foci is caused by perturbations to DNA replication. We propose that MutS directly contacts the DNA replication machinery, causing a dynamic change in the organization of DnaE at the replication fork during MMR. Our results establish a striking and intimate connection between MMR and the replicating DNA polymerase complex in vivo.
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Affiliation(s)
- Andrew D Klocko
- Department of Molecular, Cellular, and Developmental Biology, University of Michigan, Ann Arbor, MI 48109, USA
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155
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The Fanconi anemia pathway and DNA interstrand cross-link repair. Protein Cell 2011; 2:704-11. [PMID: 21948210 DOI: 10.1007/s13238-011-1098-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2011] [Accepted: 09/05/2011] [Indexed: 10/17/2022] Open
Abstract
Fanconi anemia (FA) is an autosomal or X-linked recessive disorder characterized by chromosomal instability, bone marrow failure, cancer susceptibility, and a profound sensitivity to agents that produce DNA interstrand cross-link (ICL). To date, 15 genes have been identified that, when mutated, result in FA or an FA-like syndrome. It is believed that cellular resistance to DNA interstrand cross-linking agents requires all 15 FA or FA-like proteins. Here, we review our current understanding of how these FA proteins participate in ICL repair and discuss the molecular mechanisms that regulate the FA pathway to maintain genome stability.
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156
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Wang AT, Sengerová B, Cattell E, Inagawa T, Hartley JM, Kiakos K, Burgess-Brown NA, Swift LP, Enzlin JH, Schofield CJ, Gileadi O, Hartley JA, McHugh PJ. Human SNM1A and XPF-ERCC1 collaborate to initiate DNA interstrand cross-link repair. Genes Dev 2011; 25:1859-70. [PMID: 21896658 PMCID: PMC3175721 DOI: 10.1101/gad.15699211] [Citation(s) in RCA: 108] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 07/20/2011] [Indexed: 12/24/2022]
Abstract
One of the major DNA interstrand cross-link (ICL) repair pathways in mammalian cells is coupled to replication, but the mechanistic roles of the critical factors involved remain largely elusive. Here, we show that purified human SNM1A (hSNM1A), which exhibits a 5'-3' exonuclease activity, can load from a single DNA nick and digest past an ICL on its substrate strand. hSNM1A-depleted cells are ICL-sensitive and accumulate replication-associated DNA double-strand breaks (DSBs), akin to ERCC1-depleted cells. These DSBs are Mus81-induced, indicating that replication fork cleavage by Mus81 results from the failure of the hSNM1A- and XPF-ERCC1-dependent ICL repair pathway. Our results reveal how collaboration between hSNM1A and XPF-ERCC1 is necessary to initiate ICL repair in replicating human cells.
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Affiliation(s)
- Anderson T. Wang
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Blanka Sengerová
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Emma Cattell
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Takabumi Inagawa
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Janet M. Hartley
- Cancer Research UK Drug–DNA Interactions Research Group, UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Konstantinos Kiakos
- Cancer Research UK Drug–DNA Interactions Research Group, UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | | | - Lonnie P. Swift
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | - Jacqueline H. Enzlin
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
| | | | - Opher Gileadi
- Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, United Kingdom
| | - John A. Hartley
- Cancer Research UK Drug–DNA Interactions Research Group, UCL Cancer Institute, University College London, London WC1E 6BT, United Kingdom
| | - Peter J. McHugh
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, United Kingdom
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157
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Ko JC, Tsai MS, Weng SH, Kuo YH, Chiu YF, Lin YW. Curcumin enhances the mitomycin C-induced cytotoxicity via downregulation of MKK1/2–ERK1/2-mediated Rad51 expression in non-small cell lung cancer cells. Toxicol Appl Pharmacol 2011; 255:327-38. [DOI: 10.1016/j.taap.2011.07.012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Revised: 07/06/2011] [Accepted: 07/15/2011] [Indexed: 01/20/2023]
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158
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Ricceri F, Porcedda P, Allione A, Turinetto V, Polidoro S, Guarrera S, Rosa F, Voglino F, Pezzotti A, Minieri V, Accomasso L, Cibrario Rocchietti E, Orlando L, Giachino C, Matullo G. Involvement of MRE11A and XPA gene polymorphisms in the modulation of DNA double-strand break repair activity: a genotype-phenotype correlation study. DNA Repair (Amst) 2011; 10:1044-50. [PMID: 21880556 DOI: 10.1016/j.dnarep.2011.08.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2011] [Revised: 07/25/2011] [Accepted: 08/07/2011] [Indexed: 10/17/2022]
Abstract
DNA double-strand breaks (DSB) are the most lethal form of ionizing radiation-induced DNA damage, and failure to repair them results in cell death. In order to see if any associations exist between DNA repair gene polymorphisms and phenotypic profiles of DSB repair (DSBR) we performed a genotype-phenotype correlation study in 118 young healthy subjects (mean age 25.8±6.7years). Subjects were genotyped for 768 single nucleotide polymorphisms (SNPs) with a custom Illumina Golden Gate Assay, and an H2AX histone phosphorylation assay was done to test DSBR capacity. We found that H2AX phosphorylation at 1h was significantly lower in subjects heterozygous (no variant homozygotes were observed) for the XPA gene SNP rs3176683 (p-value=0.005), while dephosphorylation was significantly higher in subjects carrying the variant allele in three MRE11A gene SNPs: rs1014666, rs476137 and rs2508784 (p-value=0.003, 0.003 and 0.008, respectively). An additive effect of low-activity DNA repair alleles was associated with altered DSBR activity, as demonstrated by both H2AX phosphorylation at 1 h (p-trend <0.0001) and γH2AX dephosphorylation at 3h (p-trend <0.0001). Our study revealed that in addition to SNPs of genes that are well-established players in DSBR, non-DSBR genes, such as the XPA gene that is mainly involved in the nucleotide excision repair pathway, can also influence DSBR in healthy subjects. This suggests that successful DSBR may require both DSBR and non-DSBR mechanisms.
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159
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Abstract
DNA interstrand cross-links (ICLs) are critical cytotoxic lesions produced by cancer chemotherapeutic agents such as the nitrogen mustards and platinum drugs; however, the exact mechanism of ICL-induced cell death is unclear. Here, we show a novel mechanism of p53-independent apoptotic cell death involving prolonged cell-cycle (G2) arrest, ICL repair involving HR, transient mitosis, incomplete cytokinesis, and gross chromosomal abnormalities resulting from ICLs in mammalian cells. This characteristic ‘giant' cell death, observed by using time-lapse video microscopy, was reduced in ICL repair ERCC1- and XRCC3-deficient cells. Collectively, the results illustrate the coordination of ICL-induced cellular responses, including cell-cycle arrest, DNA damage repair, and cell death.
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160
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Sanjiv K, Su TL, Suman S, Kakadiya R, Lai TC, Wang HY, Hsiao M, Lee TC. The novel DNA alkylating agent BO-1090 suppresses the growth of human oral cavity cancer in xenografted and orthotopic mouse models. Int J Cancer 2011; 130:1440-50. [DOI: 10.1002/ijc.26142] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2010] [Accepted: 03/29/2011] [Indexed: 02/03/2023]
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161
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Episkopou H, Kyrtopoulos SA, Sfikakis PP, Dimopoulos MA, Souliotis VL. The repair of melphalan-induced DNA adducts in the transcribed strand of active genes is subject to a strong polarity effect. Mutat Res 2011; 714:78-87. [PMID: 21762707 DOI: 10.1016/j.mrfmmm.2011.06.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Revised: 06/10/2011] [Accepted: 06/28/2011] [Indexed: 11/18/2022]
Abstract
To investigate the mechanisms of the therapeutic action and drug resistance to the nitrogen mustard melphalan, melphalan-induced DNA damage repair and chromatin structure were examined along the p53, N-ras and d-globin gene loci in cells carrying different repair activities. In nucleotide excision repair-deficient XP-A cells, similar levels of adducts were found in all fragments examined, indicating uniform distribution of DNA damage. In both, repair-proficient CS-B and XP-C cells, faster repair was observed in regions inside the transcribed N-ras and p53 genes, compared to regions on both sides outside of the genes, while no such difference was observed for the inactive d-globin gene. Moreover, very fast adduct repair on the transcribed strand of the active genes was seen immediately downstream of the transcription start site, together with a steeply decreasing gradient of repair efficiency along the gene towards the 3'-end. In all cells analyzed, the above variation in DNA repair efficiency was paralleled exactly by the variation in the degree of local chromatin condensation, more relaxed chromatin being associated with faster repair. Similar results were obtained using peripheral blood mononuclear cells from healthy volunteers, suggesting that the existence of a repair gradient along transcribed genes may be a universal phenomenon. In conclusion, these findings demonstrate that the repair of melphalan adducts in the transcribed strand of active genes is subject to a strong polarity effect arising from variations in the chromatin structure.
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Affiliation(s)
- Hara Episkopou
- Institute of Biological Research and Biotechnology, National Hellenic Research Foundation, Athens, Greece
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162
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Inoue H. Exploring the processes of DNA repair and homologous integration in Neurospora. Mutat Res 2011; 728:1-11. [PMID: 21757027 DOI: 10.1016/j.mrrev.2011.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/16/2011] [Indexed: 12/23/2022]
Abstract
This review offers a personal perspective on historical developments related to our current understanding of DNA repair, recombination, and homologous integration in Neurospora crassa. Previous reviews have summarized and analyzed the characteristics of Neurospora DNA repair mutants. The early history is reviewed again here as a prelude to a discussion of the molecular cloning, annotation, gene disruption and reverse genetics of Neurospora DNA repair genes. The classical studies and molecular analysis are then linked in a perspective on new directions in research on mutagen-sensitive mutants.
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Affiliation(s)
- Hirokazu Inoue
- Laboratory of Genetics, Department of Regulation Biology, Faculty of Science, Saitama University, Urawa 338-8570, Japan.
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163
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Abstract
Deinococcus radiodurans is a robust bacterium best known for its capacity to repair massive DNA damage efficiently and accurately. It is extremely resistant to many DNA-damaging agents, including ionizing radiation and UV radiation (100 to 295 nm), desiccation, and mitomycin C, which induce oxidative damage not only to DNA but also to all cellular macromolecules via the production of reactive oxygen species. The extreme resilience of D. radiodurans to oxidative stress is imparted synergistically by an efficient protection of proteins against oxidative stress and an efficient DNA repair mechanism, enhanced by functional redundancies in both systems. D. radiodurans assets for the prevention of and recovery from oxidative stress are extensively reviewed here. Radiation- and desiccation-resistant bacteria such as D. radiodurans have substantially lower protein oxidation levels than do sensitive bacteria but have similar yields of DNA double-strand breaks. These findings challenge the concept of DNA as the primary target of radiation toxicity while advancing protein damage, and the protection of proteins against oxidative damage, as a new paradigm of radiation toxicity and survival. The protection of DNA repair and other proteins against oxidative damage is imparted by enzymatic and nonenzymatic antioxidant defense systems dominated by divalent manganese complexes. Given that oxidative stress caused by the accumulation of reactive oxygen species is associated with aging and cancer, a comprehensive outlook on D. radiodurans strategies of combating oxidative stress may open new avenues for antiaging and anticancer treatments. The study of the antioxidation protection in D. radiodurans is therefore of considerable potential interest for medicine and public health.
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164
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Wang LC, Gautier J. The Fanconi anemia pathway and ICL repair: implications for cancer therapy. Crit Rev Biochem Mol Biol 2011; 45:424-39. [PMID: 20807115 DOI: 10.3109/10409238.2010.502166] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Fanconi anemia (FA) is an inherited disease caused by mutations in at least 13 genes and characterized by genomic instability. In addition to displaying strikingly heterogenous clinical phenotypes, FA patients are exquisitely sensitive to treatments with crosslinking agents that create interstrand crosslinks (ICL). In contrast to bacteria and yeast, in which ICLs are repaired through replication-dependent and -independent mechanisms, it is thought that ICLs are repaired primarily during DNA replication in vertebrates. However, recent data indicate that replication-independent ICL repair also operates in vertebrates. While the precise role of the FA pathway in ICL repair remains elusive, increasing evidence suggests that FA proteins function at different steps in the sensing, recognition and processing of ICLs, as well as in signaling from these very toxic lesions, which can be generated by a wide variety of cancer chemotherapeutic drugs. Here, we discuss some of the recent findings that have shed light on the role of the FA pathway in ICL repair, with special emphasis on the implications of these findings for cancer therapy since disruption of FA genes have been associated with cancer predisposition.
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Affiliation(s)
- Lily C Wang
- Institute for Cancer Genetics, Columbia University, New York, NY 10032, USA
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165
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Efimov VA, Fedyunin SV. Cross-linked nucleic acids: isolation, structure, and biological role. BIOCHEMISTRY (MOSCOW) 2011; 75:1606-27. [DOI: 10.1134/s0006297910130079] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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166
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Shapiro GI, Tibes R, Gordon MS, Wong BY, Eder JP, Borad MJ, Mendelson DS, Vogelzang NJ, Bastos BR, Weiss GJ, Fernandez C, Sutherland W, Sato H, Pierceall WE, Weaver D, Slough S, Wasserman E, Kufe DW, Von Hoff D, Kawabe T, Sharma S. Phase I studies of CBP501, a G2 checkpoint abrogator, as monotherapy and in combination with cisplatin in patients with advanced solid tumors. Clin Cancer Res 2011; 17:3431-42. [PMID: 21220472 DOI: 10.1158/1078-0432.ccr-10-2345] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE Two phase I dose-escalation studies were conducted to determine the maximum tolerated dose (MTD) and safety profile of the G(2) checkpoint abrogator CBP501, as a single agent and in combination with cisplatin. EXPERIMENTAL DESIGN Patients with advanced solid tumors were treated with CBP501 alone (D1/D8/D15, q4w, from 0.9 mg/m(2)), or with cisplatin (both on D1, q3w, from 3.6 mg/m(2) CBP501, 50 mg/m(2) cisplatin). Dose escalation proceeded if dose-limiting toxicity (DLT) was observed in 1 or less of 3 to 6 patients; CBP501 dose increments were implemented according to the incidence of toxicity. MTD was determined from DLTs occurring during the first two cycles. RESULTS In the combination study, the DLT was a histamine-release syndrome (HRS) occurring 10 to 60 minutes after initiating infusion that was attenuated by prophylaxis comprising dexamethasone, diphenhydramine, ranitidine, and loratadine. The MTD was 25 mg/m(2) CBP501 and 75 mg/m(2) cisplatin, with two patients at the highest dose (36.4 mg/m(2) CBP501, 75 mg/m(2) cisplatin) experiencing grade 3 HRS. The only DLT with monotherapy was transient G(3) rise of troponin in one patient. Grade 3 to 4 treatment-related events were rare. Promising activity was observed with CBP501/cisplatin, mainly in ovarian and mesothelioma patients who had previously progressed on platinum-containing regimens. Among ovarian cancer patients, low expression of DNA repair proteins was associated with partial response or stable disease. CONCLUSIONS CBP501 is well tolerated in patients as monotherapy and with cisplatin. At the recommended phase II dose (RP2D), the combination is feasible and HRS manageable with prophylaxis. Evidence of antitumor activity was observed in platinum-resistant patients.
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Affiliation(s)
- Geoffrey I Shapiro
- Dana-Farber Cancer Institute, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts 02215, USA.
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167
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Gospodinov A, Mladenova V, Anachkova B. Sub-Cellular Localization of TIP49 in Response to DNA Damage. BIOTECHNOL BIOTEC EQ 2011. [DOI: 10.5504/bbeq.2011.0004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
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168
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Op de Beeck M, Madder A. Unprecedented C-selective interstrand cross-linking through in situ oxidation of furan-modified oligodeoxynucleotides. J Am Chem Soc 2010; 133:796-807. [PMID: 21162525 DOI: 10.1021/ja1048169] [Citation(s) in RCA: 74] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Chemical reagents that form interstrand cross-links have been used for a long time in cancer therapy. They covalently link two strands of DNA, thereby blocking transcription. Cross-link repair enzymes, however, can restore the transcription processes, causing resistance to certain anti-cancer drugs. The mechanism of these cross-link repair processes has not yet been fully revealed. One of the obstacles in this study is the lack of sufficient amounts of well-defined, stable, cross-linked duplexes to study the pathways of cross-link repair enzymes. Our group has developed a cross-link strategy where a furan moiety is incorporated into oligodeoxynucleotides (ODNs). These furan-modified nucleic acids can form interstrand cross-links upon selective furan oxidation with N-bromosuccinimide. We here report on the incorporation of the furan moiety at the 2'-position of a uridine through an amido or ureido linker. The resulting modified ODNs display an unprecedented selectivity for cross-linking toward a cytidine opposite the modified residue, forming one specific cross-linked duplex, which could be isolated in good yield. Furthermore, the structure of the formed cross-linked duplexes could be unambiguously characterized.
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Affiliation(s)
- Marieke Op de Beeck
- Laboratory for Organic and Biomimetic Chemistry, University of Ghent, Krijgslaan 281 S4, B-9000 Ghent, Belgium
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169
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Dębiak M, Panas A, Steinritz D, Kehe K, Bürkle A. High-throughput analysis of DNA interstrand crosslinks in human peripheral blood mononuclear cells by automated reverse FADU assay. Toxicology 2010; 280:53-60. [PMID: 21115096 DOI: 10.1016/j.tox.2010.11.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 11/17/2010] [Accepted: 11/19/2010] [Indexed: 12/01/2022]
Abstract
DNA interstrand crosslinks (ICL) are induced both by several cytotoxic anti-cancer drugs as well as by the chemical warfare agent sulphur mustard (SM). Although measurement of ICL formation could be used in risk assessment or provide valuable predictive information on the response of malignant cells to crosslinking chemotherapeutic agents, respectively, it is currently not applied due to lack of appropriate standardized methodology. Here we describe a fast and convenient procedure for detection of ICL in human peripheral blood mononuclear cells (PBMC) as high-throughput method, termed 'reverse FADU assay'. This assay detects ICL based on the prevention of time-dependent alkaline unwinding of double-stranded DNA in a cell lysate that starts from single or double strand breaks. We have successfully established and optimized the reverse FADU assay by using human PBMC exposed to the model compounds mitomycin C, melphalan and SM. Our fully automated assay version is faster than currently used methods and possesses similar sensitivity. It operates in a 96-well format, thus allowing parallel analysis of multiple samples. Furthermore, we describe optimized protocols for sample preparation, with sample volume minimized to 100μl of blood, storage and shipment conditions. We conclude that the reverse FADU assay is an attractive candidate method for monitoring DNA damage induced by DNA crosslinking agents.
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Affiliation(s)
- Małgorzata Dębiak
- Molecular Toxicology Group, Department of Biology, University of Konstanz, Konstanz, Germany.
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170
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Boamah EK, Brekman A, Tomasz M, Myeku N, Figueiredo-Pereira M, Hunter S, Meyer J, Bhosle RC, Bargonetti J. DNA adducts of decarbamoyl mitomycin C efficiently kill cells without wild-type p53 resulting from proteasome-mediated degradation of checkpoint protein 1. Chem Res Toxicol 2010; 23:1151-62. [PMID: 20536192 PMCID: PMC2907727 DOI: 10.1021/tx900420k] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
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The mitomycin derivative 10-decarbamoyl mitomycin C (DMC) more rapidly activates a p53-independent cell death pathway than mitomycin C (MC). We recently documented that an increased proportion of mitosene1-β-adduct formation occurs in human cells treated with DMC in comparison to those treated with MC. Here, we compare the cellular and molecular response of human cancer cells treated with MC and DMC. We find the increase in mitosene 1-β-adduct formation correlates with a condensed nuclear morphology and increased cytotoxicity in human cancer cells with or without p53. DMC caused more DNA damage than MC in the nuclear and mitochondrial genomes. Checkpoint 1 protein (Chk1) was depleted following DMC, and the depletion of Chk1 by DMC was achieved through the ubiquitin proteasome pathway since chemical inhibition of the proteasome protected against Chk1 depletion. Gene silencing of Chk1 by siRNA increased the cytotoxicity of MC. DMC treatment caused a decrease in the level of total ubiquitinated proteins without increasing proteasome activity, suggesting that DMC mediated DNA adducts facilitate signal transduction to a pathway targeting cellular proteins for proteolysis. Thus, the mitosene-1-β stereoisomeric DNA adducts produced by the DMC signal for a p53-independent mode of cell death correlated with reduced nuclear size, persistent DNA damage, increased ubiquitin proteolysis and reduced Chk1 protein.
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Affiliation(s)
- Ernest K Boamah
- Department of Biological Sciences, Hunter College and The Graduate Center, City University of New York, 695 Park Avenue, New York, NY 10065, USA
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171
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Kondo N, Takahashi A, Ono K, Ohnishi T. DNA damage induced by alkylating agents and repair pathways. J Nucleic Acids 2010; 2010:543531. [PMID: 21113301 PMCID: PMC2989456 DOI: 10.4061/2010/543531] [Citation(s) in RCA: 164] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 08/26/2010] [Accepted: 10/12/2010] [Indexed: 12/11/2022] Open
Abstract
The cytotoxic effects of alkylating agents are strongly attenuated by cellular DNA repair processes, necessitating a clear understanding of the repair mechanisms. Simple methylating agents form adducts at N- and O-atoms. N-methylations are removed by base excision repair, AlkB homologues, or nucleotide excision repair (NER). O6-methylguanine (MeG), which can eventually become cytotoxic and mutagenic, is repaired by O6-methylguanine-DNA methyltransferase, and O6MeG:T mispairs are recognized by the mismatch repair system (MMR). MMR cannot repair the O6MeG/T mispairs, which eventually lead to double-strand breaks. Bifunctional alkylating agents form interstrand cross-links (ICLs) which are more complex and highly cytotoxic. ICLs are repaired by complex of NER factors (e.g., endnuclease xeroderma pigmentosum complementation group F-excision repair cross-complementing rodent repair deficiency complementation group 1), Fanconi anemia repair, and homologous recombination. A detailed understanding of how cells cope with DNA damage caused by alkylating agents is therefore potentially useful in clinical medicine.
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Affiliation(s)
- Natsuko Kondo
- Particle Radiation Oncology Research Center, Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka 590-0494, Japan
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172
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Somyajit K, Subramanya S, Nagaraju G. RAD51C: a novel cancer susceptibility gene is linked to Fanconi anemia and breast cancer. Carcinogenesis 2010; 31:2031-8. [PMID: 20952512 PMCID: PMC2994284 DOI: 10.1093/carcin/bgq210] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Germline mutations in many of the genes that are involved in homologous recombination (HR)-mediated DNA double-strand break repair (DSBR) are associated with various human genetic disorders and cancer. RAD51 and RAD51 paralogs are important for HR and in the maintenance of genome stability. Despite the identification of five RAD51 paralogs over a decade ago, the molecular mechanism(s) by which RAD51 paralogs regulate HR and genome maintenance remains obscure. In addition to the known roles of RAD51C in early and late stages of HR, it also contributes to activation of the checkpoint kinase CHK2. One recent study identifies biallelic mutation in RAD51C leading to Fanconi anemia-like disorder. Whereas a second study reports monoallelic mutation in RAD51C associated with increased risk of breast and ovarian cancer. These reports show RAD51C is a cancer susceptibility gene. In this review, we focus on describing the functions of RAD51C in HR, DNA damage signaling and as a tumor suppressor with an emphasis on the new roles of RAD51C unveiled by these reports.
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Affiliation(s)
- Kumar Somyajit
- Department of Biochemistry, Indian Institute of Science, Bangalore-560012, India
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173
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McManus FP, Fang Q, Booth JDM, Noronha AM, Pegg AE, Wilds CJ. Synthesis and characterization of an O(6)-2'-deoxyguanosine-alkyl-O(6)-2'-deoxyguanosine interstrand cross-link in a 5'-GNC motif and repair by human O(6)-alkylguanine-DNA alkyltransferase. Org Biomol Chem 2010; 8:4414-26. [PMID: 20714665 DOI: 10.1039/c0ob00093k] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
O(6)-2'-Deoxyguanosine-alkyl-O(6)-2'-deoxyguanosine interstrand DNA cross-links (ICLs) with a four and seven methylene linkage in a 5'-GNC- motif have been synthesized and their repair by human O6-alkylguanine-DNA alkyltransferase (hAGT) investigated. Duplexes containing 11 base-pairs with the ICLs in the center were assembled by automated DNA solid-phase synthesis using a cross-linked 2'-deoxyguanosine dimer phosphoramidite, prepared via a seven step synthesis which employed the Mitsunobu reaction to introduce the alkyl lesion at the O(6) atom of guanine. Introduction of the four and seven carbon ICLs resulted in no change in duplex stability based on UV thermal denaturation experiments compared to a non-cross-linked control. Circular dichroism spectra of these ICL duplexes exhibited features of a B-form duplex, similar to the control, suggesting that these lesions induce little overall change in structure. The efficiency of repair by hAGT was examined and it was shown that hAGT repairs both ICL containing duplexes, with the heptyl ICL repaired more efficiently relative to the butyl cross-link. These results were reproducible with various hAGT mutants including one that contains a novel V148L mutation. The ICL duplexes displayed similar binding affinities to a C145S hAGT mutant compared to the unmodified duplex with the seven carbon containing ICLs displaying slightly higher binding. Experiments with CHO cells to investigate the sensitivity of these cells to busulfan and hepsulfam demonstrate that hAGT reduces the cytotoxicity of hepsulfam suggesting that the O(6)-2'-deoxyguanosine-alkyl-O(6)-2'-deoxyguanosine interstrand DNA cross-link may account for at least part of the cytotoxicity of this agent.
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Affiliation(s)
- Francis P McManus
- Department of Chemistry and Biochemistry, Concordia University, 7141 Sherbrooke St. West, Montréal, QC, CanadaH4B 1R6
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174
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Rahn JJ, Lowery MP, Della-Coletta L, Adair GM, Nairn RS. Depletion of Werner helicase results in mitotic hyperrecombination and pleiotropic homologous and nonhomologous recombination phenotypes. Mech Ageing Dev 2010; 131:562-73. [PMID: 20708636 DOI: 10.1016/j.mad.2010.08.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2010] [Revised: 07/22/2010] [Accepted: 08/03/2010] [Indexed: 11/30/2022]
Abstract
Werner syndrome (WS) is a rare, segmental progeroid syndrome caused by defects in the WRN gene, which encodes a RecQ helicase. WRN has roles in many aspects of DNA metabolism including DNA repair and recombination. In this study, we exploited two different recombination assays previously used to describe a role for the structure-specific endonuclease ERCC1-XPF in mitotic and targeted homologous recombination. We constructed Chinese hamster ovary (CHO) cell lines isogenic with the cell lines used in these previous studies by depleting WRN using shRNA vectors. When intrachromosomal, mitotic recombination was assayed in WRN-depleted CHO cells, a hyperrecombination phenotype was observed, and a small number of aberrant recombinants were generated. Targeted homologous recombination was also examined in WRN-depleted CHO cells using a plasmid-chromosome targeting assay. In these experiments, loss of WRN resulted in a significant decrease in nonhomologous integration events and ablation of recombinants that required random integration of the corrected targeting vector. Aberrant recombinants were also recovered, but only from WRN-depleted cells. The pleiotropic recombination phenotypes conferred by WRN depletion, reflected in distinct homologous and nonhomologous recombination pathways, suggest a role for WRN in processing specific types of homologous recombination intermediates as well as an important function in nonhomologous recombination.
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Affiliation(s)
- Jennifer J Rahn
- University of Texas M.D. Anderson Cancer Center, Department of Carcinogenesis, Science Park Research Division, P.O. Box 389, Smithville, TX 78597, United States
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175
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Lenglet G, David-Cordonnier MH. DNA-Destabilizing Agents as an Alternative Approach for Targeting DNA: Mechanisms of Action and Cellular Consequences. J Nucleic Acids 2010; 2010. [PMID: 20725618 PMCID: PMC2915751 DOI: 10.4061/2010/290935] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2010] [Revised: 05/27/2010] [Accepted: 06/03/2010] [Indexed: 01/06/2023] Open
Abstract
DNA targeting drugs represent a large proportion of the actual anticancer drug pharmacopeia, both in terms of drug brands and prescription volumes. Small DNA-interacting molecules share the ability of certain proteins to change the DNA helix's overall organization and geometrical orientation via tilt, roll, twist, slip, and flip effects. In this ocean of DNA-interacting compounds, most stabilize both DNA strands and very few display helix-destabilizing properties. These types of DNA-destabilizing effect are observed with certain mono- or bis-intercalators and DNA alkylating agents (some of which have been or are being developed as cancer drugs). The formation of locally destabilized DNA portions could interfere with protein/DNA recognition and potentially affect several crucial cellular processes, such as DNA repair, replication, and transcription. The present paper describes the molecular basis of DNA destabilization, the cellular impact on protein recognition, and DNA repair processes and the latter's relationships with antitumour efficacy.
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Affiliation(s)
- Gaëlle Lenglet
- INSERM U-837, Jean-Pierre Aubert Research Center (JPARC), Team 4 Molecular and Cellular Targeting for Cancer Treatment, Institute for Research on Cancer of Lille (IRCL), Lille F-59045, France
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176
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Zhang P, Sridharan D, Lambert MW. Knockdown of mu-calpain in Fanconi anemia, FA-A, cells by siRNA restores alphaII spectrin levels and corrects chromosomal instability and defective DNA interstrand cross-link repair. Biochemistry 2010; 49:5570-81. [PMID: 20518497 DOI: 10.1021/bi100656j] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
We have previously shown that there is a deficiency in the structural protein, nonerythroid alpha spectrin (alphaIISp), in cells from patients with Fanconi anemia (FA). These studies indicate that this deficiency is due to the reduced stability of alphaIISp and correlates with a decreased level of repair of DNA interstrand cross-links and chromosomal instability in FA cells. An important factor in the stability of alphaIISp is its susceptibility to cleavage by the protease, mu-calpain. We hypothesized that an increased level of mu-calpain cleavage of alphaIISp in FA cells leads to an increased level of breakdown of alphaIISp and that knocking down expression of mu-calpain in FA cells should restore levels of alphaIISp and correct a number of the phenotypic defects observed. The results showed that there is increased mu-calpain activity in FA-A, FA-C, FA-D2, FA-F, and FA-G cells that could account for the deficiency in alphaIISp in these FA cells. Protein interaction studies indicated that FANCA and FANCG bind directly to mu-calpain. We hypothesize that this binding may lead to inhibition of mu-calpain activity in normal cells. Knocking down mu-calpain by siRNA in FA-A cells restored levels of alphaIISp to normal and reversed a number of the cellular deficiencies in these cells. It corrected the DNA repair defect and the chromosomal instability observed after exposure to a DNA interstrand cross-linking agent. These studies indicate that FA proteins may play an important role in maintaining the stability of alphaIISp in the cell by regulating its cleavage by mu-calpain. Thus, by reducing the level of breakdown of alphaIISp in FA cells, we may be able to reverse a number of the cellular deficiencies observed in this disorder.
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Affiliation(s)
- Pan Zhang
- Department of Pathology and Laboratory Medicine, New Jersey Medical School and Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA
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177
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Wang C, Lambert MW. The Fanconi anemia protein, FANCG, binds to the ERCC1-XPF endonuclease via its tetratricopeptide repeats and the central domain of ERCC1. Biochemistry 2010; 49:5560-9. [PMID: 20518486 DOI: 10.1021/bi100584c] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
There is evidence that Fanconi anemia (FA) proteins play an important role in the repair of DNA interstrand cross-links (ICLs), but the precise mechanism by which this occurs is not clear. One of the critical steps in the ICL repair process involves unhooking of the cross-link from DNA by incisions on one strand on either side of the ICL and its subsequent removal. The ERCC1-XPF endonuclease is involved in this unhooking step and in the removal of the cross-link. We have previously shown that several of the FA proteins are needed to produce incisions created by ERCC1-XPF at sites of ICLs. To more clearly establish a link between FA proteins and the incision step(s) mediated by ERCC1-XPF, we undertook yeast two-hybrid analysis to determine whether FANCA, FANCC, FANCF, and FANCG directly interact with ERCC1 and XPF and, if so, to determine the sites of interaction. One of these FA proteins, FANCG, was found to have a strong affinity for ERCC1 and a moderate affinity for XPF. FANCG has been shown to contain seven tetratricopeptide repeat (TPR) motifs, which are motifs that mediate protein-protein interactions. Mapping the sites of interaction of FANCG with ERCC1, using site-directed mutagenesis, demonstrated that TPRs 1, 3, 5, and 6 are needed for binding of FANCG to ERCC1. ERCC1, in turn, was shown to interact with FANCG via its central domain, which is different from the region of ERCC1 that binds to XPF. This binding between FANCG and the ERCC1-XPF endonuclease, combined with our previous studies which show that FANCG is involved in the incision step mediated by ERCC1-XPF, establishes a link between an FA protein and the critical unhooking step of the ICL repair process.
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Affiliation(s)
- Chuan Wang
- Department of Pathology and Laboratory Medicine, New Jersey Medical School and Graduate School of Biomedical Sciences, University of Medicine and Dentistry of New Jersey, Newark, New Jersey 07103, USA
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178
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Weng MW, Zheng Y, Jasti VP, Champeil E, Tomasz M, Wang Y, Basu AK, Tang MS. Repair of mitomycin C mono- and interstrand cross-linked DNA adducts by UvrABC: a new model. Nucleic Acids Res 2010; 38:6976-84. [PMID: 20647419 PMCID: PMC2978355 DOI: 10.1093/nar/gkq576] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Mitomycin C induces both MC-mono-dG and cross-linked dG-adducts in vivo. Interstrand cross-linked (ICL) dG-MC-dG-DNA adducts can prevent strand separation. In Escherichia coli cells, UvrABC repairs ICL lesions that cause DNA bending. The mechanisms and consequences of NER of ICL dG-MC-dG lesions that do not induce DNA bending remain unclear. Using DNA fragments containing a MC-mono-dG or an ICL dG-MC-dG adduct, we found (i) UvrABC incises only at the strand containing MC-mono-dG adducts; (ii) UvrABC makes three types of incisions on an ICL dG-MC-dG adduct: type 1, a single 5′ incision on 1 strand and a 3′ incision on the other; type 2, dual incisions on 1 strand and a single incision on the other; and type 3, dual incisions on both strands; and (iii) the cutting kinetics of type 3 is significantly faster than type 1 and type 2, and all of 3 types of cutting result in producing DSB. We found that UvrA, UvrA + UvrB and UvrA + UvrB + UvrC bind to MC-modified DNA specifically, and we did not detect any UvrB- and UvrB + UvrC–DNA complexes. Our findings challenge the current UvrABC incision model. We propose that DSBs resulted from NER of ICL dG-MC-dG adducts contribute to MC antitumor activity and mutations.
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Affiliation(s)
- Mao-wen Weng
- Department of Environmental Medicine, Pathology, and Medicine, New York University School of Medicine, Tuxedo, New York 10987, USA
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179
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Rahn JJ, Adair GM, Nairn RS. Multiple roles of ERCC1-XPF in mammalian interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:567-581. [PMID: 20658648 DOI: 10.1002/em.20583] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
DNA interstrand crosslinks (ICLs) are among the most deleterious cytotoxic lesions encountered by cells, mainly due to the covalent linkage these lesions create between the two strands of DNA which effectively blocks replication and transcription. Although ICL repair in mammalian cells is not fully understood, processing of these lesions is thought to begin by "unhooking" at the site of the damaged base accompanied by the generation of a double strand break and ultimately repair through translesion synthesis and homologous recombination. A key player in this repair process is the heterodimeric protein complex ERCC1-XPF. Although some models of ICL repair restrict ERCC1-XPF activity to the unhooking step, recent data suggest that this protein complex acts in additional downstream steps. Here, we review the evidence implicating ERCC1-XPF in multiple steps of ICL repair.
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Affiliation(s)
- Jennifer J Rahn
- Department of Carcinogenesis, Science Park-Research Division, University of Texas M.D. Anderson Cancer Center, Smithville, Texas 78957, USA.
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180
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Vasquez KM. Targeting and processing of site-specific DNA interstrand crosslinks. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:527-39. [PMID: 20196133 PMCID: PMC2895014 DOI: 10.1002/em.20557] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
DNA interstrand crosslinks (ICLs) are among the most cytotoxic types of DNA damage, and thus ICL-inducing agents such as cyclophosphamide, melphalan, cisplatin, psoralen, and mitomycin C have been used clinically as anticancer drugs for decades. ICLs can also be formed endogenously as a consequence of cellular metabolic processes. ICL-inducing agents continue to be among the most effective chemotherapeutic treatments for many cancers; however, treatment with these agents can lead to secondary malignancies, in part due to mutagenic processing of the DNA lesions. The mechanisms of ICL repair have been characterized more thoroughly in bacteria and yeast than in mammalian cells. Thus, a better understanding of the molecular mechanisms of ICL processing offers the potential to improve the efficacy of these drugs in cancer therapy. In mammalian cells, it is thought that ICLs are repaired by the coordination of proteins from several pathways, including nucleotide excision repair (NER), base excision repair (BER), mismatch repair (MMR), homologous recombination (HR), translesion synthesis (TLS), and proteins involved in Fanconi anemia (FA). In this review, we focus on the potential functions of NER, MMR, and HR proteins in the repair of and response to ICLs in human cells and in mice. We will also discuss a unique approach, using psoralen covalently linked to triplex-forming oligonucleotides to direct ICLs to specific sites in the mammalian genome.
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Affiliation(s)
- Karen M Vasquez
- Department of Carcinogenesis, The University of Texas M.D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957, USA.
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181
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Hlavin EM, Smeaton MB, Miller PS. Initiation of DNA interstrand cross-link repair in mammalian cells. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:604-24. [PMID: 20658650 PMCID: PMC2911644 DOI: 10.1002/em.20559] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Interstrand cross-links (ICLs) are among the most cytotoxic DNA lesions to cells because they prevent the two DNA strands from separating, thereby precluding replication and transcription. Even though chemotherapeutic cross-linking agents are well established in clinical use, and numerous repair proteins have been implicated in the initial events of mammalian ICL repair, the precise mechanistic details of these events remain to be elucidated. This review will summarize our current understanding of how ICL repair is initiated with an emphasis on the context (replicating, transcribed or quiescent DNA) in which the ICL is recognized, and how the chemical and physical properties of ICLs influence repair. Although most studies have focused on replication-dependent repair because of the relation to highly replicative tumor cells, replication-independent ICL repair is likely to be important in the circumvention of cross-link cytotoxicity in nondividing, terminally differentiated cells that may be challenged with exogenous or endogenous sources of ICLs. Consequently, the ICL repair pathway that should be considered "dominant" appears to depend on the cell type and the DNA context in which the ICL is encountered. The ability to define and inhibit distinct pathways of ICL repair in different cell cycle phases may help in developing methods that increase cytotoxicity to cancer cells while reducing side-effects in nondividing normal cells. This may also lead to a better understanding of pathways that protect against malignancy and aging.
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Affiliation(s)
| | | | - Paul S. Miller
- Correspondence should be addressed to Paul S. Miller, , Phone: (410)-955-3489, Fax: (410)-955-2926
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182
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Legerski RJ. Repair of DNA interstrand cross-links during S phase of the mammalian cell cycle. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:540-551. [PMID: 20658646 PMCID: PMC2911997 DOI: 10.1002/em.20566] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
DNA interstrand cross-linking (ICL) agents are widely used in anticancer chemotherapy regimens, yet our understanding of the DNA repair mechanisms by which these lesions are removed from the genome remains incomplete. This is at least in part due to the enormously complicated nature and variety of the biochemical pathways that operate on these complex lesions. In this review, we have focused specifically on the S-phase pathway of ICL repair in mammalian cells, which appears to be the major mechanism by which these lesions are removed in cycling cells. The various stages and components of this pathway are discussed, and a putative molecular model is presented. In addition, we propose an explanation as to how this pathway can lead to the observed high levels of sister chromatid exchanges known to be induced by ICLs.
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Affiliation(s)
- Randy J Legerski
- Department of Genetics, The University of Texas M.D. Anderson Cancer Center, Houston, Texas 77030, USA.
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183
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Cantor SB, Xie J. Assessing the link between BACH1/FANCJ and MLH1 in DNA crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:500-507. [PMID: 20658644 DOI: 10.1002/em.20568] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
FANCJ (also known as BRIP1 or BACH1) is a DNA helicase that was originally identified by its direct interaction with the hereditary breast cancer protein, BRCA1. Similar to BRCA1, FANCJ function is essential for DNA repair and breast cancer suppression. FANCJ is also mutated in the cancer prone syndrome Fanconi anemia, for which patient cells are characterized by extreme sensitivity to agents that generate DNA interstand crosslinks. Unexpectedly, correction of the interstrand crosslink sensitivity of FANCJ-null patient cells did not require the FANCJ/BRCA1 interaction. Instead, FANCJ binding to the mismatch repair protein, MLH1 was required. Given this finding, we address the role of FANCJ and MLH1 in DNA crosslink processing and how their functions could be linked in checkpoint and/or recombination pathways. We speculate that after DNA crosslink processing and repair, the FANCJ/MLH1 interaction is critical for recovery and restart of replication. These ideas are considered and summarized in this review.
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Affiliation(s)
- Sharon B Cantor
- Department of Cancer Biology, University of Massachusetts Medical School, Worcester, Massachusetts 01605, USA.
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184
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Wood RD. Mammalian nucleotide excision repair proteins and interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:520-6. [PMID: 20658645 PMCID: PMC3017513 DOI: 10.1002/em.20569] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Although various schemes for interstrand crosslink (ICL) repair incorporate DNA recombination, replication, and double-strand break intermediate steps, action of the nucleotide excision repair (NER) system or some variation of it is a common feature of most models. In the bacterium Escherichia coli, the NER enzyme UvrABC can incise on either side of an ICL to unhook the crosslink, and can proceed via a subsequent recombination step. The relevance of NER to ICL repair in mammalian cells has been challenged. Of all NER mutants, it is clear that ERCC1 and XPF-defective cells show the most pronounced sensitivities to ICL-inducing agents, and defects in ICL repair. However, there is good evidence that cells defective in NER proteins including XPA and XPG are also more sensitive than normal to ICL-inducing agents. These results are summarized here, together with evidence for defective crosslink removal in NER-defective cells. Studies of incision at sites of ICL by cell extracts and purified proteins have been done, but these studies are not all consistent with one another and further research is required.
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Affiliation(s)
- Richard D Wood
- Department of Carcinogenesis and The University of Texas Graduate School of Biomedical Sciences at Houston, The University of Texas M. D. Anderson Cancer Center, Science Park-Research Division, Smithville, Texas 78957, USA.
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185
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Ho TV, Schärer OD. Translesion DNA synthesis polymerases in DNA interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:552-566. [PMID: 20658647 DOI: 10.1002/em.20573] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
DNA interstrand crosslinks (ICLs) are induced by a number of bifunctional antitumor drugs such as cisplatin, mitomycin C, or the nitrogen mustards as well as endogenous agents formed by lipid peroxidation. The repair of ICLs requires the coordinated interplay of a number of genome maintenance pathways, leading to the removal of ICLs through at least two distinct mechanisms. The major pathway of ICL repair is dependent on replication, homologous recombination, and the Fanconi anemia (FA) pathway, whereas a minor, G0/G1-specific and recombination-independent pathway depends on nucleotide excision repair. A central step in both pathways in vertebrates is translesion synthesis (TLS) and mutants in the TLS polymerases Rev1 and Pol zeta are exquisitely sensitive to crosslinking agents. Here, we review the involvement of Rev1 and Pol zeta as well as additional TLS polymerases, in particular, Pol eta, Pol kappa, Pol iota, and Pol nu, in ICL repair. Biochemical studies suggest that multiple TLS polymerases have the ability to bypass ICLs and that the extent ofbypass depends upon the structure as well as the extent of endo- or exonucleolytic processing of the ICL. As has been observed for lesions that affect only one strand of DNA, TLS polymerases are recruited by ubiquitinated proliferating nuclear antigen (PCNA) to repair ICLs in the G0/G1 pathway. By contrast, this data suggest that a different mechanism involving the FA pathway is operative in coordinating TLS in the context of replication-dependent ICL repair.
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Affiliation(s)
- The Vinh Ho
- Department of Pharmacological Sciences, Stony Brook University, Stony Brook, New York 11794-3400, USA
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186
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Cattell E, Sengerová B, McHugh PJ. The SNM1/Pso2 family of ICL repair nucleases: from yeast to man. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:635-645. [PMID: 20175117 DOI: 10.1002/em.20556] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Efficient interstrand crosslink (ICL) repair in yeast depends on the Pso2/Snm1 protein. Pso2 is a member of the highly conserved metallo-beta-lactamase structural family of nucleases. Mammalian cells possess three SNM1/Pso2 related proteins, SNM1A, SNM1B/Apollo, and SNM1C/Artemis. Evidence that SNM1A and SNM1B contribute to ICL repair is mounting, whereas Artemis appears to primarily contribute to non-ICL repair pathways, particularly some double-strand break repair events. Yeast Pso2 and all three mammalian SNM1-family proteins have been shown to possess nuclease activity. Here, we review the biochemical, genetic, and cellular evidence for the SNM1 family as DNA repair factors, focusing on ICL repair.
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Affiliation(s)
- Emma Cattell
- Weatherall Institute of Molecular Medicine, University of Oxford, John Radcliffe Hospital, Oxford OX3 9DS, UK
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187
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Hinz JM. Role of homologous recombination in DNA interstrand crosslink repair. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:582-603. [PMID: 20658649 DOI: 10.1002/em.20577] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Homologous recombination repair (HRR) encompasses mechanisms that employ homologous DNA sequences as templates for repair or tolerance of a wide range of DNA lesions that inhibit DNA replication in S phase. Arguably the most imposing of these DNA lesions is that of the interstrand crosslink (ICL), consisting of a covalently attached chemical bridge between opposing DNA strands. ICL repair requires the coordinated activities of HRR and a number of proteins from other DNA repair and damage response systems, including nucleotide excision repair, base excision repair, mismatch repair, and translesion DNA synthesis (TLS). Interestingly, different organisms favor alternative methods of HRR in the ICL repair process. E. coli perform ICL repair using a homology-driven damage bypass mechanism analogous to daughter strand gap repair. Eukaryotes from yeast to humans initiate ICL repair primarily during DNA replication, relying on HRR activity to restart broken replication forks associated with double-strand break intermediates induced by nucleolytic activities of other excision repair factors. Higher eukaryotes also employ several additional factors, including members of the Fanconi anemia damage-response network, which further promote replication-associated ICL repair through the activation and coordination of various DNA excision repair, TLS, and HRR proteins. This review focuses on the proteins and general mechanisms of HRR associated with ICL repair in different model organisms.
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Affiliation(s)
- John M Hinz
- School of Molecular Biosciences, Washington State University, Pullman, Washington, USA.
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188
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Macé-Aimé G, Couvé S, Khassenov B, Rosselli F, Saparbaev MK. The Fanconi anemia pathway promotes DNA glycosylase-dependent excision of interstrand DNA crosslinks. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:508-519. [PMID: 20120016 DOI: 10.1002/em.20548] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Fanconi anemia (FA) is a recessive cancer prone syndrome featuring bone marrow failure and hypersensitivity to DNA interstrand crosslinks (ICLs) and, to a milder extension, to ionizing radiation and oxidative stress. Recently, we reported that human oxidative DNA glycosylase, NEIL1 excises with high efficiency the unhooked crosslinked oligomer within three-stranded DNA repair intermediate induced by photoactivated psoralen exposure. Complete reconstitution of repair of the ICL within a three-stranded DNA structure shows that it is processed in the short-patch base excision repair (BER) pathway. To examine whether the DNA damage hypersensitivity in FA cells follows impaired BER activities, we measured DNA glycosylase and AP endonuclease activities in cell-free extracts from wild-type, FA, and FA-corrected cells. We showed that immortalized lymphoid cells of FA complementation Groups A, C, and D and from control cells from normal donors contain similar BER activities. Intriguingly, the cellular level of NEIL1 protein strongly depends on the intact FA pathway suggesting that the hypersensitivity of FA cells to ICLs may, at least in part, arise from downregulation or degradation of NEIL1. Consistent with this result, plasmid-based expression of the FLAG-tagged NEIL1 protein partially complements the hypersensitivity FA cells to the crosslinking agents exposures, suggesting that NEIL1 specifically complements impaired capability of FA cells to repair ICLs and oxidative DNA damage. These findings shed light to how the FA pathway may regulate DNA repair proteins and bring explanation for the long-time disputed problem of the oxidative stress sensitive phenotype of FA cells.
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Affiliation(s)
- Gaëtane Macé-Aimé
- CNRS UMR8200 Groupe, Voie FANC/BRCA et Cancer, Université Paris-Sud, Institut de Cancérologie Gustave Roussy, F-94805 Villejuif Cedex, France
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189
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McVey M. Strategies for DNA interstrand crosslink repair: insights from worms, flies, frogs, and slime molds. ENVIRONMENTAL AND MOLECULAR MUTAGENESIS 2010; 51:646-658. [PMID: 20143343 DOI: 10.1002/em.20551] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
DNA interstrand crosslinks (ICLs) are complex lesions that covalently link both strands of the DNA double helix and impede essential cellular processes such as DNA replication and transcription. Recent studies suggest that multiple repair pathways are involved in their removal. Elegant genetic analysis has demonstrated that at least three distinct sets of pathways cooperate in the repair and/or bypass of ICLs in budding yeast. Although the mechanisms of ICL repair in mammals appear similar to those in yeast, important differences have been documented. In addition, mammalian crosslink repair requires other repair factors, such as the Fanconi anemia proteins, whose functions are poorly understood. Because many of these proteins are conserved in simpler metazoans, nonmammalian models have become attractive systems for studying the function(s) of key crosslink repair factors. This review discusses the contributions that various model organisms have made to the field of ICL repair. Specifically, it highlights how studies performed with C. elegans, Drosophila, Xenopus, and the social amoeba Dictyostelium serve to complement those from bacteria, yeast, and mammals. Together, these investigations have revealed that although the underlying themes of ICL repair are largely conserved, the complement of DNA repair proteins utilized and the ways in which each of the proteins is used can vary substantially between different organisms.
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Affiliation(s)
- Mitch McVey
- Department of Biology, Tufts University, Medford, Massachusetts 02155, USA.
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190
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Discrepancy between in vitro and in vivo antitumor effect of a new platinum(II) metallointercalator. Invest New Drugs 2010; 29:1164-76. [DOI: 10.1007/s10637-010-9461-z] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2010] [Accepted: 05/14/2010] [Indexed: 12/31/2022]
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191
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Hlavin EM, Smeaton MB, Noronha AM, Wilds CJ, Miller PS. Cross-link structure affects replication-independent DNA interstrand cross-link repair in mammalian cells. Biochemistry 2010; 49:3977-88. [PMID: 20373772 DOI: 10.1021/bi902169q] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
DNA interstrand cross-links (ICLs) are cytotoxic products of common anticancer drugs and cellular metabolic processes, whose mechanism(s) of repair remains poorly understood. In this study, we show that cross-link structure affects ICL repair in nonreplicating reporter plasmids that contain a mispaired N(4)C-ethyl-N(4)C (C-C), N3T-ethyl-N3T (T-T), or N1I-ethyl-N3T (I-T) ICL. The T-T and I-T cross-links obstruct the hydrogen bond face of the base and mimic the N1G-ethyl-N3C ICL created by bis-chloroethylnitrosourea, whereas the C-C cross-link does not interfere with base pair formation. Host-cell reactivation (HCR) assays in human and hamster cells showed that repair of these ICLs primarily involves the transcription-coupled nucleotide excision repair (TC-NER) pathway. Repair of the C-C ICL was 5-fold more efficient than repair of the T-T or I-T ICLs, suggesting the latter cross-links hinder lesion bypass following initial ICL unhooking. The level of luciferase expression from plasmids containing a C-C cross-link remnant on either the transcribed or nontranscribed strand increased in NER-deficient cells, indicating NER involvement occurs at a step prior to remnant removal, whereas expression from similar T-T remnant plasmids was inhibited in NER-deficient cells, demonstrating NER is required for remnant removal. Sequence analysis of repaired plasmids showed a high proportion of C residues inserted at the site of the T-T and I-T cross-links, and HCR assays showed that Rev1 was likely responsible for these insertions. In contrast, both C and G residues were inserted at the C-C cross-link site, and Rev1 was not required for repair, suggesting replicative or other translesion polymerases can bypass the C-C remnant.
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Affiliation(s)
- Erica M Hlavin
- Department of Biochemistry and Molecular Biology, Bloomberg School of Public Health, Johns Hopkins University, 615 North Wolfe Street, Baltimore, Maryland 21205, USA
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192
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Efimov VA, Fediunin SV, Chakhmakhcheva OG. [Cross-linked nucleic acids: formation, structure, and biological function]. RUSSIAN JOURNAL OF BIOORGANIC CHEMISTRY 2010; 36:56-80. [PMID: 20386579 DOI: 10.1134/s1068162010010061] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Published data on the main types of reagents capable of introducing covalent interstrand cross links into nucleic acids (NA) are summarized in the present review. The reactivity of cross-linking agents, their preferred binding sites, and methods of determining the cross-link localization in a duplex are discussed. Cell response to DNA cross linking, namely, the blocking of replication and transcription, the initiation of reparation processes, and apoptotic death of the cell, are analyzed, as well as the use of cross-linking reagents in therapy and molecular biology.
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193
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Mutations in the Bacillus subtilis beta clamp that separate its roles in DNA replication from mismatch repair. J Bacteriol 2010; 192:3452-63. [PMID: 20453097 DOI: 10.1128/jb.01435-09] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The beta clamp is an essential replication sliding clamp required for processive DNA synthesis. The beta clamp is also critical for several additional aspects of DNA metabolism, including DNA mismatch repair (MMR). The dnaN5 allele of Bacillus subtilis encodes a mutant form of beta clamp containing the G73R substitution. Cells with the dnaN5 allele are temperature sensitive for growth due to a defect in DNA replication at 49 degrees C, and they show an increase in mutation frequency caused by a partial defect in MMR at permissive temperatures. We selected for intragenic suppressors of dnaN5 that rescued viability at 49 degrees C to determine if the DNA replication defect could be separated from the MMR defect. We isolated three intragenic suppressors of dnaN5 that restored growth at the nonpermissive temperature while maintaining an increase in mutation frequency. All three dnaN alleles encoded the G73R substitution along with one of three novel missense mutations. The missense mutations isolated were S22P, S181G, and E346K. Of these, S181G and E346K are located near the hydrophobic cleft of the beta clamp, a common site occupied by proteins that bind the beta clamp. Using several methods, we show that the increase in mutation frequency resulting from each dnaN allele is linked to a defect in MMR. Moreover, we found that S181G and E346K allowed growth at elevated temperatures and did not have an appreciable effect on mutation frequency when separated from G73R. Thus, we found that specific residue changes in the B. subtilis beta clamp separate the role of the beta clamp in DNA replication from its role in MMR.
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194
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Blanco MG, Matos J, Rass U, Ip SCY, West SC. Functional overlap between the structure-specific nucleases Yen1 and Mus81-Mms4 for DNA-damage repair in S. cerevisiae. DNA Repair (Amst) 2010; 9:394-402. [PMID: 20106725 DOI: 10.1016/j.dnarep.2009.12.017] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2009] [Revised: 11/23/2009] [Accepted: 12/21/2009] [Indexed: 11/16/2022]
Abstract
In eukaryotic cells, multiple DNA repair mechanisms respond to a wide variety of DNA lesions. Homologous recombination-dependent repair provides a pathway for dealing with DNA double-strand breaks and replication fork demise. A key step in this process is the resolution of recombination intermediates such as Holliday junctions (HJs). Recently, nucleases from yeast (Yen1) and human cells (GEN1) were identified that can resolve HJ intermediates, in a manner analogous to the E. coli HJ resolvase RuvC. Here, we have analyzed the role of Yen1 in DNA repair in S. cerevisiae, and show that while yen1Delta mutants are repair-proficient, yen1Delta mus81Delta double mutants are exquisitely sensitive to a variety of DNA-damaging agents that disturb replication fork progression. This phenotype is dependent upon RAD52, indicating that toxic recombination intermediates accumulate in the absence of Yen1 and Mus81. After MMS treatment, yen1Delta mus81Delta double mutants arrest with a G2 DNA content and unsegregated chromosomes. These findings indicate that Yen1 can act upon recombination/repair intermediates that arise in MUS81-defective cells following replication fork damage.
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Affiliation(s)
- Miguel G Blanco
- London Research Institute, Cancer Research UK, South Mimms, Herts, UK.
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195
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Targeting the FANCJ-BRCA1 interaction promotes a switch from recombination to poleta-dependent bypass. Oncogene 2010; 29:2499-508. [PMID: 20173781 DOI: 10.1038/onc.2010.18] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
BRCA1 and the DNA helicase FANCJ (also known as BACH1 or BRIP1) have common functions in breast cancer suppression and DNA repair. However, the functional significance of the direct interaction between BRCA1 and FANCJ remains unclear. Here, we have discovered that BRCA1 binding to FANCJ regulates DNA damage repair choice. Thus, when FANCJ binding to BRCA1 is ablated, the molecular mechanism chosen for the repair of damaged DNA is dramatically altered. Specifically, a FANCJ protein that cannot be phosphorylated at serine 990 or bind BRCA1 inhibits DNA repair via homologous recombination and promotes poleta-dependent bypass. Furthermore, the poleta-dependent bypass promoted by FANCJ requires the direct binding to the mismatch repair (MMR) protein, MLH1. Together, our findings implicate that in human cells BRCA1 binding to FANCJ is critical to regulate DNA repair choice and promote genomic stability. Moreover, unregulated FANCJ function could be associated with cancer and/or chemoresistance.
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196
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Rübe CE, Fricke A, Schneider R, Simon K, Kühne M, Fleckenstein J, Gräber S, Graf N, Rübe C. DNA repair alterations in children with pediatric malignancies: novel opportunities to identify patients at risk for high-grade toxicities. Int J Radiat Oncol Biol Phys 2010; 78:359-69. [PMID: 20153123 DOI: 10.1016/j.ijrobp.2009.08.052] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2009] [Revised: 08/10/2009] [Accepted: 08/10/2009] [Indexed: 12/21/2022]
Abstract
PURPOSE To evaluate, in a pilot study, the phosphorylated H2AX (γH2AX) foci approach for identifying patients with double-strand break (DSB) repair deficiencies, who may overreact to DNA-damaging cancer therapy. METHODS AND MATERIALS The DSB repair capacity of children with solid cancers was analyzed compared with that of age-matched control children and correlated with treatment-related normal-tissue responses (n = 47). Double-strand break repair was investigated by counting γH2AX foci in blood lymphocytes at defined time points after irradiation of blood samples. RESULTS Whereas all healthy control children exhibited proficient DSB repair, 3 children with tumors revealed clearly impaired DSB repair capacities, and 2 of these repair-deficient children developed life-threatening or even lethal normal-tissue toxicities. The underlying mutations affecting regulatory factors involved in DNA repair pathways were identified. Moreover, significant differences in mean DSB repair capacity were observed between children with tumors and control children, suggesting that childhood cancer is based on genetic alterations affecting DSB repair function. CONCLUSIONS Double-strand break repair alteration in children may predispose to cancer formation and may affect children's susceptibility to normal-tissue toxicities. Phosphorylated H2AX analysis of blood samples allows one to detect DSB repair deficiencies and thus enables identification of children at risk for high-grade toxicities.
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Affiliation(s)
- Claudia E Rübe
- Department of Radiation Oncology, Saarland University, Homburg/Saar, Germany.
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197
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Ding H, Greenberg MM. DNA damage and interstrand cross-link formation upon irradiation of aryl iodide C-nucleotide analogues. J Org Chem 2010; 75:535-44. [PMID: 20067226 PMCID: PMC2813935 DOI: 10.1021/jo902071y] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The 5-halopyrimidine nucleotides damage DNA upon UV-irradiation or exposure to gamma-radiolysis via the formation of the 2'-deoxyuridin-5-yl sigma-radical. The bromo and iodo derivatives of these molecules are useful tools for probing DNA structure and as therapeutically useful radiosensitizing agents. A series of aryl iodide C-nucleotides were incorporated into synthetic oligonucleotides and exposed to UV-irradiation and gamma-radiolysis. The strand damage produced upon irradiation of DNA containing these molecules is consistent with the generation of highly reactive sigma-radicals. Direct stand breaks and alkali-labile lesions are formed at the nucleotide analogue and flanking nucleotides. The distribution of lesion type and location varies depending upon the position of the aryl ring that is iodinated. Unlike 5-halopyrimidine nucleotides, the aryl iodides produce interstrand cross-links in duplex regions of DNA when exposed to gamma-radiolysis or UV-irradiation. Quenching studies suggest that cross-links are produced by gamma-radiolysis via capture of a solvated electron, and subsequent fragmentation to the sigma-radical. These observations suggest that aryl iodide C-nucleotide analogues may be useful as probes for excess electron transfer and radiosensitizing agents.
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Affiliation(s)
- Hui Ding
- Department of Chemistry, Johns Hopkins University, 3400 N. Charles Street, Baltimore, Maryland 21218, USA
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198
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Muniandy PA, Liu J, Majumdar A, Liu ST, Seidman MM. DNA interstrand crosslink repair in mammalian cells: step by step. Crit Rev Biochem Mol Biol 2010; 45:23-49. [PMID: 20039786 PMCID: PMC2824768 DOI: 10.3109/10409230903501819] [Citation(s) in RCA: 142] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Interstrand DNA crosslinks (ICLs) are formed by natural products of metabolism and by chemotherapeutic reagents. Work in E. coli identified a two cycle repair scheme involving incisions on one strand on either side of the ICL (unhooking) producing a gapped intermediate with the incised oligonucleotide attached to the intact strand. The gap is filled by recombinational repair or lesion bypass synthesis. The remaining monoadduct is then removed by nucleotide excision repair (NER). Despite considerable effort, our understanding of each step in mammalian cells is still quite limited. In part this reflects the variety of crosslinking compounds, each with distinct structural features, used by different investigators. Also, multiple repair pathways are involved, variably operative during the cell cycle. G(1) phase repair requires functions from NER, although the mechanism of recognition has not been determined. Repair can be initiated by encounters with the transcriptional apparatus, or a replication fork. In the case of the latter, the reconstruction of a replication fork, stalled or broken by collision with an ICL, adds to the complexity of the repair process. The enzymology of unhooking, the identity of the lesion bypass polymerases required to fill the first repair gap, and the functions involved in the second repair cycle are all subjects of active inquiry. Here we will review current understanding of each step in ICL repair in mammalian cells.
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Affiliation(s)
- Parameswary A Muniandy
- Laboratory of Molecular Gerontology, National Institute on Aging, National Institutes of Health, Baltimore, MD 21224, USA
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199
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Peng X, Ghosh AK, Van Houten B, Greenberg MM. Nucleotide excision repair of a DNA interstrand cross-link produces single- and double-strand breaks. Biochemistry 2010; 49:11-9. [PMID: 20000382 DOI: 10.1021/bi901603h] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The DNA radical resulting from formal abstraction of a hydrogen atom from the thymidine methyl group, 5-(2'-deoxyuridinyl)methyl radical, forms interstrand cross-links with the opposing 2'-deoxyadenosine. This is the first chemically characterized, radical-mediated cross-link between two opposing nucleotides. In addition, cross-linking between opposing bases in the duplex is less common than between those separated by one or two nucleotides. The first step in cross-link repair was investigated using the UvrABC bacterial nucleotide excision repair system. UvrABC incised both strands of the cross-linked DNA, although the strand containing the cross-linked purine was preferred by the enzyme in two different duplexes. The incision sites in one strand were spaced 11-14 nucleotides apart, as is typical for UvrABC incision. The majority of incisions occur at the third phosphate from the 3'-side of the cross-link and eighth or ninth phosphate on the 5'-side. In addition, cleavage was found to occur on both strands, producing double-strand breaks in approximately 25-29% of the incision events. This is the first example of double-strand cleavage during nucleotide excision repair of cross-linked DNA that does not already contain a strand break in the vicinity of the cross-link.
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Affiliation(s)
- Xiaohua Peng
- Department of Chemistry, Johns Hopkins University, 3400 North Charles Street, Baltimore, Maryland 21218, USA
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200
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Lee KY, Chung KY, Koo HS. The involvement of FANCM, FANCI, and checkpoint proteins in the interstrand DNA crosslink repair pathway is conserved in C. elegans. DNA Repair (Amst) 2010; 9:374-82. [PMID: 20075016 DOI: 10.1016/j.dnarep.2009.12.018] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2009] [Revised: 11/28/2009] [Accepted: 12/17/2009] [Indexed: 10/20/2022]
Abstract
Fanconi anemia (FA) patients are specifically defective in the repair of interstrand DNA crosslinks (ICLs), a complex process involving at least 13 FA proteins and other repair/checkpoint proteins. Of the 13 FA proteins, FANCD1/BRCA2, FANCD2, and FANCJ were previously found to be functionally conserved in C. elegans. We have also identified C. elegans homologs of FANCM and FANCI, and determined their epistatic relationships with homologs of FANCD2, checkpoint proteins, and RAD51 upon DNA crosslinking. The counterparts of FANCM, FANCI, and three checkpoint proteins (RPA, ATR and CHK1) are required for focus formation and ubiquitination associated with FANCD2 in C. elegans. However, C. elegans FANCM affects neither RPA focus formation nor CHK1 phosphorylation induced by ICLs, unlike the reported role of human FANCM, which influences ATR-CHK1 signaling at stalled replication forks. Although focus formation by both FANCD2 and RAD51 requires ATR-CHK1 signaling, FANCD2 and RAD51 acted independently in the formation of their respective foci. Thus, the FANCD2 activation pathway involving FANCM, FANCI, and the checkpoint proteins is conserved in C. elegans but with distinct differences.
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Affiliation(s)
- Kyong Yun Lee
- Department of Biochemistry, Yonsei University, Seodaemun-ku, Seoul, Republic of Korea
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