Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

  • Review Article
  • Published:

Balancing repair and tolerance of DNA damage caused by alkylating agents

Nature Reviews Cancer volume 12, pages 104–120 (2012)Cite this article

Subjects

Key Points

  • Chemotherapeutic alkylating agents induce a range of cytotoxic and mutagenic adducts onto DNA.

  • Alkylating agent-induced damage to DNA is sensed and repaired by different cellular mechanisms, including direct repair by the AlkB homologue (ALKBH) family and O6-methylguanine-DNA methyltransferase (MGMT) proteins or by pathways such as base excision repair (BER), mismatch repair (MMR), homologous recombination, Fanconi anaemia and translesion DNA synthesis (TLS).

  • Diverse cellular pathways collectively modulate alkylation sensitivity, and imbalances within or between these pathways can have deleterious consequences at the cellular and whole-animal levels.

  • Developing agents to modulate DNA repair pathways is a promising strategy to increase the effectiveness of current chemotherapeutic alkylating agents.

  • Investigation of DNA repair capacity in cancer patients may provide crucial information about which chemotherapeutic therapies to use, because differences can result in drastic variation in alkylation sensitivity.

Abstract

Alkylating agents constitute a major class of frontline chemotherapeutic drugs that inflict cytotoxic DNA damage as their main mode of action, in addition to collateral mutagenic damage. Numerous cellular pathways, including direct DNA damage reversal, base excision repair (BER) and mismatch repair (MMR), respond to alkylation damage to defend against alkylation-induced cell death or mutation. However, maintaining a proper balance of activity both within and between these pathways is crucial for a favourable response of an organism to alkylating agents. Furthermore, the response of an individual to alkylating agents can vary considerably from tissue to tissue and from person to person, pointing to genetic and epigenetic mechanisms that modulate alkylating agent toxicity.

This is a preview of subscription content, access via your institution

Access options

Buy this article

  • Purchase on Springer Link
  • Instant access to full article PDF
Buy now

Prices may be subject to local taxes which are calculated during checkout

Figure 1: Sites of alkylation on DNA bases.
Figure 2: DNA lesions induced by monofunctional and bifunctional chemotherapeutic alkylating agents.
Figure 3: Mammalian repair and tolerance mechanisms for DNA alkyl lesions.
Figure 4: DNA repair mechanisms for alkylated bases.
Figure 5: Cellular processing and repair of 3meA lesions in DNA.
Figure 6: Cellular processing and repair of O6meG lesions in DNA.

Similar content being viewed by others

References

  1. Ballschmiter, K. Pattern and sources of naturally produced organohalogens in the marine environment: biogenic formation of organohalogens. Chemosphere 52, 313–324 (2003).

    Article  CAS  PubMed  Google Scholar 

  2. Hecht, S. S. DNA adduct formation from tobacco-specific N-nitrosamines. Mutat. Res. 424, 127–142 (1999).

    Article  CAS  PubMed  Google Scholar 

  3. Hamilton, J. T., McRoberts, W. C., Keppler, F., Kalin, R. M. & Harper, D. B. Chloride methylation by plant pectin: an efficient environmentally significant process. Science 301, 206–209 (2003).

    Article  CAS  PubMed  Google Scholar 

  4. Rydberg, B. & Lindahl, T. Nonenzymatic methylation of DNA by the intracellular methyl group donor S-adenosyl-L-methionine is a potentially mutagenic reaction. EMBO J. 1, 211–216 (1982).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. Taverna, P. & Sedgwick, B. Generation of an endogenous DNA-methylating agent by nitrosation in Escherichia coli. J. Bacteriol. 178, 5105–5111 (1996).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  6. Bartsch, H., O'Neill, I. K., Schulte-Hermann, R. & International Agency for Research on Cancer. Relevance of N-Nitroso Compounds to Human Cancer: Exposures and Mechanisms (Oxford Univ. Press distributor, Lyon, London, 1987).

    Google Scholar 

  7. Kufe, D. W. et al. (eds) Cancer Medicine, 6th edn (BC Decker, Hamilton, Canada, 2003).

    Google Scholar 

  8. Shrivastav, N., Li, D. & Essigmann, J. M. Chemical biology of mutagenesis and DNA repair: cellular responses to DNA alkylation. Carcinogenesis 31, 59–70 (2010).

    Article  CAS  PubMed  Google Scholar 

  9. Drablos, F. et al. Alkylation damage in DNA and RNA-repair mechanisms and medical significance. DNA Repair 3, 1389–1407 (2004).

    Article  CAS  PubMed  Google Scholar 

  10. Johnson, R. E., Yu, S.-L., Prakash, S. & Prakash, L. A Role for yeast and human translesion synthesis DNA polymerases in promoting replication through 3-methyl adenine. Mol. Cell. Biol. 27, 7198–7205 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. Engelward, B. P. et al. A chemical and genetic approach together define the biological consequences of 3-methyladenine lesions in the mammalian genome. J. Biol. Chem. 273, 5412–5418 (1998).

    Article  CAS  PubMed  Google Scholar 

  12. Gate, L. & Tew, K. D. in Cancer Management in Man: Chemotherapy, Biological Therapy, Hyperthermia and Supporting Measures (ed. Minev, B. R.) 61–85 (Springer Netherlands, 2011).

    Book  Google Scholar 

  13. Sedgwick, B., Bates, P. A., Paik, J., Jacobs, S. C. & Lindahl, T. Repair of alkylated DNA: recent advances. DNA Repair 6, 429–442 (2007).

    Article  CAS  PubMed  Google Scholar 

  14. Samson, L., Thomale, J. & Rajewsky, M. F. Alternative pathways for the in vivo repair of O6-alkylguanine and O4-alkylthymine in Escherichia coli: the adaptive response and nucleotide excision repair. EMBO J. 7, 2261–2267 (1988).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  15. Huang, J. C., Hsu, D. S., Kazantsev, A. & Sancar, A. Substrate spectrum of human excinuclease: repair of abasic sites, methylated bases, mismatches, and bulky adducts. Proc. Natl Acad. Sci. USA 91, 12213–12217 (1994).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  16. Hanawalt, P. Subpathways of nucleotide excision repair and their regulation. Oncogene 21, 8949–8956 (2002).

    Article  CAS  PubMed  Google Scholar 

  17. Kaina, B., Christmann, M., Naumann, S. & Roos, W. P. MGMT: key node in the battle against genotoxicity, carcinogenicity and apoptosis induced by alkylating agents. DNA Repair 6, 1079–1099 (2007).

    Article  CAS  PubMed  Google Scholar 

  18. Deans, A. J. & West, S. C. DNA interstrand crosslink repair and cancer. Nature Rev. Cancer 11, 467–480 (2011).

    Article  CAS  Google Scholar 

  19. Kee, Y. & D'Andrea, A. D. Expanded roles of the Fanconi anemia pathway in preserving genomic stability. Genes Dev. 24, 1680–1694 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. Lange, S. S., Takata, K. & Wood, R. D. DNA polymerases and cancer. Nature Rev. Cancer 11, 96–110 (2011). References 16–20 describe additional pathways that are important in the repair and tolerance of DNA alkylation damage that were not described in detail in this Review.

    Article  CAS  Google Scholar 

  21. Svilar, D., Goellner, E. M., Almeida, K. H. & Sobol, R. W. Base excision repair and lesion-dependent subpathways for repair of oxidative DNA damage. Antioxid. Redox Signal. 14, 2491–2507 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  22. Monti, P. et al. Rev1 and Polzeta influence toxicity and mutagenicity of Me-lex, a sequence selective N3-adenine methylating agent. DNA Repair 7, 431–438 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  23. Monti, P. et al. Mutagenicity of N3-methyladenine: a multi-translesion polymerase affair. Mutat. Res. 683, 50–56 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. Roos, W. P. et al. The translesion polymerase Rev3L in the tolerance of alkylating anticancer drugs. Mol. Pharmacol. 76, 927–934 (2009). This paper and references 10, 22 and 23 show that TLS polymerases have a crucial role in determining alkylating agent sensitivity through the bypass of replication-blocking 3meA lesions.

    Article  CAS  PubMed  Google Scholar 

  25. Prasad, R., Shock, D. D., Beard, W. A. & Wilson, S. H. Substrate channeling in mammalian base excision repair pathways: passing the baton. J. Biol. Chem. 285, 40479–40488 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. Mol, C. D., Izumi, T., Mitra, S. & Tainer, J. A. DNA-bound structures and mutants reveal abasic DNA binding by APE1 DNA repair and coordination. Nature 403, 451–456 (2000). The structural and mutational analysis described in this paper provided the basis of the mechanism that toxic BER intermediates are passed from one BER enzyme to another, as reviewed in reference 25.

    Article  CAS  PubMed  Google Scholar 

  27. Sieber, O. M. et al. Multiple colorectal adenomas, classic adenomatous polyposis, and germ-line mutations in MYH. N. Engl. J. Med. 348, 791–799 (2003).

    Article  PubMed  Google Scholar 

  28. Fleischmann, C. et al. Comprehensive analysis of the contribution of germline MYH variation to early-onset colorectal cancer. Int. J. Cancer 109, 554–558 (2004).

    Article  CAS  PubMed  Google Scholar 

  29. Rusyn, I. et al. Transcriptional networks in S. cerevisiae linked to an accumulation of base excision repair intermediates. PLoS ONE 2, e1252 (2007).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  30. Meira, L. B. et al. Aag-initiated base excision repair drives alkylation-induced retinal degeneration in mice. Proc. Natl Acad. Sci. USA 106, 888–893 (2009). This paper was the first to illustrate that deficiency of a DNA glycosylase in vivo results in protection from alkylation damage, specifically MMS-mediated retinal degeneration.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  31. Sobol, R. W. et al. Base excision repair intermediates induce p53-independent cytotoxic and genotoxic responses. J. Biol. Chem. 278, 39951–39959 (2003).

    Article  CAS  PubMed  Google Scholar 

  32. Fishel, M. L., He, Y., Smith, M. L. & Kelley, M. R. Manipulation of base excision repair to sensitize ovarian cancer cells to alkylating agent temozolomide. Clin. Cancer Res. 13, 260–267 (2007).

    Article  CAS  PubMed  Google Scholar 

  33. Kaasen, I., Evensen, G. & Seeberg, E. Amplified expression of the tag+ and alkA+ genes in Escherichia coli: identification of gene products and effects on alkylation resistance. J. Bacteriol. 168, 642–647 (1986).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. Xiao, W. & Samson, L. In vivo evidence for endogenous DNA alkylation damage as a source of spontaneous mutation in eukaryotic cells. Proc. Natl Acad. Sci. USA 90, 2117–2121 (1993).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. Glassner, B. J., Rasmussen, L. J., Najarian, M. T., Posnick, L. M. & Samson, L. D. Generation of a strong mutator phenotype in yeast by imbalanced base excision repair. Proc. Natl Acad. Sci. USA 95, 9997–10002 (1998). References 33–35 illustrate that BER intermediates are toxic and mutagenic; an imbalance in the BER pathway results in increased mutagenesis, as well as in enhanced alkylation sensitivity.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. Posnick, L. M. & Samson, L. D. Imbalanced base excision repair increases spontaneous mutation and alkylation sensitivity in Escherichia coli. J. Bacteriol. 181, 6763–6771 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  37. Calleja, F., Jansen, J. G., Vrieling, H., Laval, F. & van Zeeland, A. A. Modulation of the toxic and mutagenic effects induced by methyl methanesulfonate in Chinese hamster ovary cells by overexpression of the rat N-alkylpurine-DNA glycosylase. Mutat. Res. 425, 185–194 (1999).

    Article  CAS  PubMed  Google Scholar 

  38. Rinne, M., Caldwell, D. & Kelley, M. R. Transient adenoviral N-methylpurine DNA glycosylase overexpression imparts chemotherapeutic sensitivity to human breast cancer cells. Mol. Cancer Ther. 3, 955–967 (2004).

    CAS  PubMed  Google Scholar 

  39. Rinne, M. L., He, Y., Pachkowski, B. F., Nakamura, J. & Kelley, M. R. N-methylpurine DNA glycosylase overexpression increases alkylation sensitivity by rapidly removing non-toxic 7-methylguanine adducts. Nucleic Acids Res. 33, 2859–2867 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  40. Trivedi, R. N. et al. Human methyl purine DNA glycosylase and DNA polymerase β expression collectively predict sensitivity to temozolomide. Mol. Pharmacol. 74, 505–516 (2008).

    Article  CAS  PubMed  Google Scholar 

  41. Coquerelle, T., Dosch, J. & Kaina, B. Overexpression of N-methylpurine-DNA glycosylase in Chinese hamster ovary cells renders them more sensitive to the production of chromosomal aberrations by methylating agents-a case of imbalanced DNA repair. Mutat. Res. 336, 9–17 (1995).

    Article  CAS  PubMed  Google Scholar 

  42. Klapacz, J. et al. Frameshift mutagenesis and microsatellite instability induced by human alkyladenine DNA glycosylase. Mol. Cell 37, 843–853 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. Hofseth, L. J. et al. The adaptive imbalance in base excision-repair enzymes generates microsatellite instability in chronic inflammation. J. Clin. Invest. 112, 1887–1894 (2003). This paper clearly describes a correlation between imbalanced BER and microsatellite instability in human tissues.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  44. Cerda, S. R., Turk, P. W., Thor, A. D. & Weitzman, S. A. Altered expression of the DNA repair protein, N-methylpurine-DNA glycosylase (MPG) in breast cancer. FEBS Lett. 431, 12–18 (1998).

    Article  CAS  PubMed  Google Scholar 

  45. Curtis, C. D., Thorngren, D. L. & Nardulli, A. M. Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues. BMC Cancer 10, 9 (2010).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  46. Kim, N. K. et al. Expression of the DNA repair enzyme, N-methylpurine-DNA glycosylase (MPG) in astrocytic tumors. Anticancer Res. 23, 1417–1423 (2003).

    CAS  PubMed  Google Scholar 

  47. Mirabello, L. et al. A comprehensive candidate gene approach identifies genetic variation associated with osteosarcoma. BMC Cancer 11, 209 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. Elder, R. H. et al. Alkylpurine-DNA-N-glycosylase knockout mice show increased susceptibility to induction of mutations by methyl methanesulfonate. Mol. Cell. Biol. 18, 5828–5837 (1998).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  49. Engelward, B. P. et al. Base excision repair deficient mice lacking the Aag alkyladenine DNA glycosylase. Proc. Natl Acad. Sci. USA 94, 13087–13092 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. Roth, R. B. & Samson, L. D. 3-Methyladenine DNA glycosylase-deficient Aag null mice display unexpected bone marrow alkylation resistance. Cancer Res. 62, 656–660 (2002). This paper reports the surprising discovery that AAG deficiency can protect against MMS toxicity in ex vivo bone marrow assays.

    CAS  PubMed  Google Scholar 

  51. Cardinal, J. W. et al. Increased susceptibility to streptozotocin-induced β-cell apoptosis and delayed autoimmune diabetes in alkylpurine-DNA-N-glycosylase-deficient mice. Mol. Cell. Biol. 21, 5605–5613 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. Burns, N. & Gold, B. The effect of 3-methyladenine DNA glycosylase-mediated DNA repair on the induction of toxicity and diabetes by the β-cell toxicant streptozotocin. Toxicol. Sci. 95, 391–400 (2007).

    Article  CAS  PubMed  Google Scholar 

  53. Paik, J., Duncan, T., Lindahl, T. & Sedgwick, B. Sensitization of human carcinoma cells to alkylating agents by small interfering RNA suppression of 3-alkyladenine-DNA glycosylase. Cancer Res. 65, 10472–10477 (2005).

    Article  CAS  PubMed  Google Scholar 

  54. Engelward, B. P. et al. Repair-deficient 3-methyladenine DNA glycosylase homozygous mutant mouse cells have increased sensitivity to alkylation-induced chromosome damage and cell killing. EMBO J. 15, 945–952 (1996). References 49 and 54 describe the generation of Aag−/− embryonic stem cells and Aag−/− mice, and show that in certain cell types AAG deficiency results in increased alkylation sensitivity.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  55. Wirtz, S. et al. Both base excision repair and O6-methylguanine-DNA methyltransferase protect against methylation-induced colon carcinogenesis. Carcinogenesis 31, 2111–2117 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  56. Meira, L. B. et al. DNA damage induced by chronic inflammation contributes to colon carcinogenesis in mice. J. Clin. Invest. 118, 2516–2525 (2008).

    CAS  PubMed  PubMed Central  Google Scholar 

  57. Liu, L., Taverna, P., Whitacre, C. M., Chatterjee, S. & Gerson, S. L. Pharmacologic disruption of base excision repair sensitizes mismatch repair-deficient and -proficient colon cancer cells to methylating agents. Clin. Cancer Res. 5, 2908–2917 (1999).

    CAS  PubMed  Google Scholar 

  58. Loeb, L. A. & Preston, B. D. Mutagenesis by Apurinic/Apyrimidinic Sites. Annu. Rev. Genet. 20, 201–230 (1986).

    Article  CAS  PubMed  Google Scholar 

  59. Kunz, B. A. et al. Specificity of the mutator caused by deletion of the yeast structural gene (APN1) for the major apurinic endonuclease. Proc. Natl Acad. Sci. USA 91, 8165–8169 (1994).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  60. Luo, M. & Kelley, M. R. Inhibition of the human apurinic/apyrimidinic endonuclease (APE1) repair activity and sensitization of breast cancer cells to DNA alkylating agents with lucanthone. Anticancer Res. 24, 2127–2134 (2004).

    CAS  PubMed  Google Scholar 

  61. Wang, D., Luo, M. & Kelley, M. R. Human apurinic endonuclease 1 (APE1) expression and prognostic significance in osteosarcoma: enhanced sensitivity of osteosarcoma to DNA damaging agents using silencing RNA APE1 expression inhibition. Mol. Cancer Ther. 3, 679–686 (2004).

    CAS  PubMed  Google Scholar 

  62. Taverna, P. et al. Methoxyamine potentiates DNA single strand breaks and double strand breaks induced by temozolomide in colon cancer cells. Mutat. Res. 485, 269–281 (2001).

    Article  CAS  PubMed  Google Scholar 

  63. Wilson, D. & Simeonov, A. Small molecule inhibitors of DNA repair nuclease activities of APE1. Cell. Mol. Life Sci. 67, 3621–3631 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  64. Sobol, R. W. et al. Requirement of mammalian DNA polymerase-β in base-excision repair. Nature 379, 183–186 (1996).

    Article  CAS  PubMed  Google Scholar 

  65. Cabelof, D. C. et al. Base excision repair deficiency caused by polymerase β haploinsufficiency: accelerated DNA damage and increased mutational response to carcinogens. Cancer Res. 63, 5799–5807 (2003).

    CAS  PubMed  Google Scholar 

  66. Sobol, R. W. et al. Mutations associated with base excision repair deficiency and methylation-induced genotoxic stress. Proc. Natl Acad. Sci. USA 99, 6860–6865 (2002).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  67. Poltoratsky, V., Horton, J. K., Prasad, R. & Wilson, S. H. REV1 mediated mutagenesis in base excision repair deficient mouse fibroblast. DNA Repair 4, 1182–1188 (2005).

    Article  CAS  PubMed  Google Scholar 

  68. Horton, J. K., Joyce-Gray, D. F., Pachkowski, B. F., Swenberg, J. A. & Wilson, S. H. Hypersensitivity of DNA polymerase β null mouse fibroblasts reflects accumulation of cytotoxic repair intermediates from site-specific alkyl DNA lesions. DNA Repair 2, 27–48 (2003).

    Article  CAS  PubMed  Google Scholar 

  69. Sobol, R. W. et al. The lyase activity of the DNA repair protein β-polymerase protects from DNA-damage-induced cytotoxicity. Nature 405, 807–810 (2000). Reference 64 illustrates how Pol β is required for BER and that Pol β deficiency results in hypersensitivity to alkylating agents. Mutational analysis described in reference 69 demonstrates that the 5′-dRP lyase activity of Pol β is sufficient to protect against alkylating agent toxicity.

    Article  CAS  PubMed  Google Scholar 

  70. Wang, L., Bhattacharyya, N., Rabi, T. & Banerjee, S. Mammary carcinogenesis in transgenic mice expressing a dominant-negative mutant of DNA polymerase β in their mammary glands. Carcinogenesis 28, 1356–1363 (2007).

    Article  CAS  PubMed  Google Scholar 

  71. Chan, K. et al. Overexpression of DNA polymerase β results in an increased rate of frameshift mutations during base excision repair. Mutagenesis 22, 183–188 (2007).

    Article  CAS  PubMed  Google Scholar 

  72. Yamada, N. A. & Farber, R. A. Induction of a low level of microsatellite instability by overexpression of DNA polymerase β. Cancer Res. 62, 6061–6064 (2002).

    CAS  PubMed  Google Scholar 

  73. Almeida, K. H. & Sobol, R. W. A unified view of base excision repair: lesion-dependent protein complexes regulated by post-translational modification. DNA Repair 6, 695–711 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  74. Ström, C. E. et al. Poly (ADP-ribose) polymerase (PARP) is not involved in base excision repair but PARP inhibition traps a single-strand intermediate. Nucleic Acids Res. 39, 3166–3175 (2010).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  75. Zdzienicka, M. Z. et al. A Chinese hamster ovary cell mutant (EM-C11) with sensitivity to simple alkylating agents and a very high level of sister chromatid exchanges. Mutagenesis 7, 265–269 (1999).

    Article  Google Scholar 

  76. Horton, J. K. et al. XRCC1 and DNA polymerase β in cellular protection against cytotoxic DNA single-strand breaks. Cell Res. 18, 48–63 (2008).

    Article  CAS  PubMed  Google Scholar 

  77. Briegert, M. & Kaina, B. Human monocytes, but not dendritic cells derived from them, are defective in base excision repair and hypersensitive to methylating agents. Cancer Res. 67, 26–31 (2007).

    Article  CAS  PubMed  Google Scholar 

  78. Jiang, Y., Zhou, S., Sandusky, G. E., Kelley, M. R. & Fishel, M. L. Reduced expression of DNA repair and redox signaling protein APE1/Ref-1 impairs human pancreatic cancer cell survival, proliferation, and cell cycle progression. Cancer Invest. 28, 885–895 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  79. Al-Attar, A. et al. Human apurinic/apyrimidinic endonuclease (APE1) is a prognostic factor in ovarian, gastro-oesophageal and pancreatico-biliary cancers. Br. J. Cancer 102, 704–709 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  80. Di Maso, V. et al. Subcellular localization of APE1/Ref-1 in human hepatocellular carcinoma: possible prognostic significance. Mol. Med. 13, 89–96 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  81. Freitas, S., Moore, D. H., Michael, H. & Kelley, M. R. Studies of apurinic/apyrimidinic endonuclease/ref-1 expression in epithelial ovarian cancer. Clin. Cancer Res. 9, 4689–4694 (2003).

    CAS  PubMed  Google Scholar 

  82. Kakolyris, S. et al. Nuclear localization of human AP endonuclease 1 (HAP1/Ref-1) associates with prognosis in early operable non-small cell lung cancer (NSCLC). The J. Pathol. 189, 351–357 (1999).

    Article  CAS  PubMed  Google Scholar 

  83. Sweasy, J. B., Lang, T. & DiMaio, D. Is base excision repair a tumor suppressor mechanism? Cell Cycle 5, 250–259 (2006).

    Article  CAS  PubMed  Google Scholar 

  84. Starcevic, D., Dalal, S. & Sweasy, J. B. Is there a link between DNA polymerase β and cancer? Cell Cycle 3, 996–999 (2004).

    Article  Google Scholar 

  85. Jiang, J., Zhang, X., Yang, H. & Wang, W. Polymorphisms of DNA repair genes: ADPRT, XRCC1, and XPD and cancer risk in genetic epidemiology. Methods Mol. Biol. 471, 305–333 (2009).

    Article  CAS  PubMed  Google Scholar 

  86. Simeonov, A. et al. Identification and characterization of inhibitors of human apurinic/apyrimidinic endonuclease APE1. PLoS ONE 4, e5740 (2009).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  87. Bapat, A. et al. Novel small-molecule inhibitor of apurinic/apyrimidinic endonuclease 1 blocks proliferation and reduces viability of glioblastoma cells. J. Pharmacol. Exp. Ther. 334, 988–998 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  88. Tang, J.-b. et al. N-methylpurine DNA glycosylase and DNA polymerase β modulate BER inhibitor potentiation of glioma cells to temozolomide. Neuro Oncol. 13, 471–486 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  89. Liu, L. & Gerson, S. L. Therapeutic impact of methoxyamine: blocking repair of abasic sites in the base excision repair pathway. Curr. Opin. Investig. Drugs 5, 623–627 (2004).

    CAS  PubMed  Google Scholar 

  90. Jiang, Y. et al. Role of APE1 in differentiated neuroblastoma SH-SY5Y cells in response to oxidative stress: use of APE1 small molecule inhibitors to delineate APE1 functions. DNA Repair 8, 1273–1282 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  91. Izumi, T. et al. Two essential but distinct functions of the mammalian abasic endonuclease. Proc. Natl Acad. Sci. USA 102, 5739–5743 (2005). This study clearly showed that APE contains two domains with independent functions, both of which are essential for cell survival.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  92. Wilson, S. et al. Base excision repair and design of small molecule inhibitors of human DNA polymerase β. Cell. Mol. Life Sci. 67, 3633–3647 (2010). References 89 and 92 illustrate the strategies and progress made in developing drugs that inhibit BER as cancer chemotherapeutic agents.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  93. Hu, H. Y. et al. Identification of small molecule synthetic inhibitors of DNA polymerase β by NMR chemical shift mapping. J. Biol. Chem. 279, 39736–39744 (2004).

    Article  CAS  PubMed  Google Scholar 

  94. Jaiswal, A. S. et al. A novel inhibitor of DNA polymerase β enhances the ability of temozolomide to impair the growth of colon cancer cells. Mol. Cancer Res. 7, 1973–1983 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  95. Jaiswal, A. S. et al. DNA polymerase β as a novel target for chemotherapeutic intervention of colorectal cancer. PLoS ONE 6, e16691 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  96. Stachelek, G. C. et al. Potentiation of temozolomide cytotoxicity by inhibition of DNA polymerase β is accentuated by BRCA2 mutation. Cancer Res. 70, 409–417 (2010).

    Article  CAS  PubMed  Google Scholar 

  97. Rouleau, M., Patel, A., Hendzel, M. J., Kaufmann, S. H. & Poirier, G. G. PARP inhibition: PARP1 and beyond. Nature Rev. Cancer 10, 293–301 (2010).

    Article  CAS  Google Scholar 

  98. Mégnin-Chanet, F., Bollet, M. & Hall, J. Targeting poly(ADP-ribose) polymerase activity for cancer therapy. Cell. Mol. Life Sci. 67, 3649–3662 (2010).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  99. de Murcia, J. M. et al. Requirement of poly(ADP-ribose) polymerase in recovery from DNA damage in mice and in cells. Proc. Natl Acad. Sci. USA 94, 7303–7307 (1997).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  100. Shibata, A. et al. Parp-1 deficiency causes an increase of deletion mutations and insertions/rearrangements in vivo after treatment with an alkylating agent. Oncogene 24, 1328–1337 (2005).

    Article  CAS  PubMed  Google Scholar 

  101. Bryant, H. E. et al. Specific killing of BRCA2-deficient tumours with inhibitors of poly(ADP-ribose) polymerase. Nature 434, 913–917 (2005).

    Article  CAS  PubMed  Google Scholar 

  102. Farmer, H. et al. Targeting the DNA repair defect in BRCA mutant cells as a therapeutic strategy. Nature 434, 917–921 (2005). References 101 and 102 are seminal papers that describe synthetic lethality following treatment of BRCA-deficient cells with PARP inhibitors, which has since resulted in clinical trials testing the efficacy of PARP inhibitors in patients with breast cancer, as reviewed in reference 97.

    Article  CAS  PubMed  Google Scholar 

  103. Jelezcova, E. et al. Parp1 activation in mouse embryonic fibroblasts promotes Pol β-dependent cellular hypersensitivity to alkylation damage. Mutat. Res. 686, 57–67 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  104. Kelley, M. R. DNA repair inhibitors: where do we go from here? DNA Repair 10, 1183–1185 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  105. Pegg, A. E. Multifaceted roles of alkyltransferase and related proteins in DNA repair, DNA damage, resistance to chemotherapy, and research tools. Chem. Res. Toxicol. 24, 618–639 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  106. Nakatsuru, Y. et al. O6-methylguanine-DNA methyltransferase protects against nitrosamine-induced hepatocarcinogenesis. Proc. Natl Acad. Sci. USA 90, 6468–6472 (1993).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  107. Dumenco, L. L., Allay, E., Norton, K. & Gerson, S. L. The prevention of thymic lymphomas in transgenic mice by human O6-alkylguanine-DNA alkyltransferase. Science 259, 219–222 (1993). References 106 and 107 were the first to demonstrate that transgenic overexpression of MGMT in mice confers resistance to alkylating agent-induced carcinogenesis and reduced tumour formation.

    Article  CAS  PubMed  Google Scholar 

  108. Liu, L., Allay, E., Dumenco, L. L. & Gerson, S. L. Rapid repair of O6-methylguanine-DNA adducts protects transgenic mice from N-methylnitrosourea-induced thymic lymphomas. Cancer Res. 54, 4648–4652 (1994).

    CAS  PubMed  Google Scholar 

  109. Allay, E., Veigl, M. & Gerson, S. L. Mice over-expressing human O6 alkylguanine-DNA alkyltransferase selectively reduce O6 methylguanine mediated carcinogenic mutations to threshold levels after N-methyl-N-nitrosourea. Oncogene 18, 3783–3787 (1999).

    Article  CAS  PubMed  Google Scholar 

  110. Zhou, Z. Q. et al. Spontaneous hepatocellular carcinoma is reduced in transgenic mice overexpressing human O6- methylguanine-DNA methyltransferase. Proc. Natl Acad. Sci. USA 98, 12566–12571 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  111. Zaidi, N. H. et al. Transgenic expression of human MGMT protects against azoxymethane-induced aberrant crypt foci and G to A mutations in the K-ras oncogene of mouse colon. Carcinogenesis 16, 451–456 (1995).

    Article  CAS  PubMed  Google Scholar 

  112. Becker, K., Dosch, J., Gregel, C. M., Martin, B. A. & Kaina, B. Targeted expression of human O6-methylguanine-DNA methyltransferase (MGMT) in transgenic mice protects against tumor initiation in two-stage skin carcinogenesis. Cancer Res. 56, 3244–3249 (1996).

    CAS  PubMed  Google Scholar 

  113. Becker, K. et al. DNA repair protein MGMT protects against N-methyl-N-nitrosourea-induced conversion of benign into malignant tumors. Carcinogenesis 24, 541–546 (2003).

    Article  CAS  PubMed  Google Scholar 

  114. Becker, K., Gregel, C. M. & Kaina, B. The DNA repair protein O6-methylguanine-DNA methyltransferase protects against skin tumor formation induced by antineoplastic chloroethylnitrosourea. Cancer Res. 57, 3335–3338 (1997).

    CAS  PubMed  Google Scholar 

  115. Allay, E. et al. Potentiation of lymphomagenesis by methylnitrosourea in mice transgenic for LMO1 is blocked by O6-alkylguanine DNA-alkyltransferase. Oncogene 15, 2127–2132 (1997).

    Article  CAS  PubMed  Google Scholar 

  116. Qin, X., Zhou, H., Liu, L. & Gerson, S. L. Transgenic expression of human MGMT blocks the hypersensitivity of PMS2-deficient mice to low dose MNU thymic lymphomagenesis. Carcinogenesis 20, 1667–1673 (1999).

    Article  CAS  PubMed  Google Scholar 

  117. Qin, X., Liu, L. & Gerson, S. L. Mice defective in the DNA mismatch gene PMS2 are hypersensitive to MNU induced thymic lymphoma and are partially protected by transgenic expression of human MGMT. Oncogene 18, 4394–4400 (1999).

    Article  CAS  PubMed  Google Scholar 

  118. Reese, J. S., Allay, E. & Gerson, S. L. Overexpression of human O6-alkylguanine DNA alkyltransferase (AGT) prevents MNU induced lymphomas in heterozygous p53 deficient mice. Oncogene 20, 5258–5263 (2001).

    Article  CAS  PubMed  Google Scholar 

  119. Kisby, G. E. et al. DNA repair modulates the vulnerability of the developing brain to alkylating agents. DNA Repair 8, 400–412 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  120. Tsuzuki, T. et al. Targeted disruption of the DNA repair methyltransferase gene renders mice hypersensitive to alkylating agent. Carcinogenesis 17, 1215–1220 (1996).

    Article  CAS  PubMed  Google Scholar 

  121. Glassner, B. J. et al. DNA repair methyltransferase (Mgmt) knockout mice are sensitive to the lethal effects of chemotherapeutic alkylating agents. Mutagenesis 14, 339–347 (1999).

    Article  CAS  PubMed  Google Scholar 

  122. Klapacz, J. et al. O6-methylguanine-induced cell death involves exonuclease 1 as well as DNA mismatch recognition in vivo. Proc. Natl Acad. Sci. USA 106, 576–581 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  123. Reese, J. S., Qin, X., Ballas, C. B., Sekiguchi, M. & Gerson, S. L. MGMT expression in murine bone marrow is a major determinant of animal survival after alkylating agent exposure. J. Hematother. Stem Cell Res. 10, 115–123 (2001).

    Article  CAS  PubMed  Google Scholar 

  124. Sakumi, K. et al. Methylnitrosourea-induced tumorigenesis in MGMT gene knockout mice. Cancer Res. 57, 2415–2418 (1997).

    CAS  Google Scholar 

  125. Iwakuma, T. et al. High incidence of nitrosamine-induced tumorigenesis in mice lacking DNA repair methyltransferase. Carcinogenesis 18, 1631–1635 (1997).

    Article  CAS  PubMed  Google Scholar 

  126. Hansen, R. J., Nagasubramanian, R., Delaney, S. M., Samson, L. D. & Dolan, M. E. Role of O6-methylguanine-DNA methyltransferase in protecting from alkylating agent-induced toxicity and mutations in mice. Carcinogenesis 28, 1111–1116 (2007).

    Article  CAS  PubMed  Google Scholar 

  127. Christmann, M., Verbeek, B., Roos, W. P. & Kaina, B. O6-Methylguanine-DNA methyltransferase (MGMT) in normal tissues and tumors: enzyme activity, promoter methylation and immunohistochemistry. Biochim. Biophys. Acta 1816, 179–190 (2011). This comprehensive review summarizes the vast number of studies on MGMT expression, activity and promoter methylation in human tissues and cancers.

    CAS  PubMed  Google Scholar 

  128. Hongeng, S. et al. O6-Methylguanine-DNA methyltransferase protein levels in pediatric brain tumors. Clin. Cancer Res. 3, 2459–2463 (1997).

    CAS  PubMed  Google Scholar 

  129. Bobola, M. S. et al. O6-methylguanine-DNA methyltransferase in pediatric primary brain tumors. Clin. Cancer Res. 7, 613–619 (2001).

    CAS  PubMed  Google Scholar 

  130. Hegi, M. E. et al. MGMT gene silencing and benefit from temozolomide in glioblastoma. N. Engl. J. Med. 352, 997–1003 (2005).

    Article  CAS  PubMed  Google Scholar 

  131. Christmann, M. et al. MGMT activity, promoter methylation and immunohistochemistry of pretreatment and recurrent malignant gliomas: a comparative study on astrocytoma and glioblastoma. Int. J. Cancer 127, 2106–2118 (2010).

    Article  CAS  PubMed  Google Scholar 

  132. Kaina, B., Margison, G. & Christmann, M. Targeting O6-methylguanine-DNA methyltransferase with specific inhibitors as a strategy in cancer therapy. Cell. Mol. Life Sci. 67, 3663–3681 (2010).

    Article  CAS  PubMed  Google Scholar 

  133. Weingart, J. et al. Phase I trial of polifeprosan 20 with carmustine implant plus continuous infusion of intravenous O6-benzylguanine in adults with recurrent malignant glioma: new approaches to brain tumor therapy CNS consortium trial. J. Clin. Oncol. 25, 399–404 (2007).

    Article  CAS  PubMed  Google Scholar 

  134. Quinn, J. A. et al. Phase II trial of temozolomide plus O6-benzylguanine in adults with recurrent, temozolomide-resistant malignant glioma. J. Clin. Oncol. 27, 1262–1267 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  135. Batts, E. et al. O6-benzylguanine and BCNU in multiple myeloma: a phase II trial. Cancer Chemother. Pharmacol. 60, 415–421 (2007).

    Article  CAS  PubMed  Google Scholar 

  136. Gajewski, T. F. et al. Phase II trial of the O6-alkylguanine DNA alkyltransferase inhibitor O6-benzylguanine and 1,3-bis(2-chloroethyl)-1-nitrosourea in advanced melanoma. Clin. Cancer Res. 11, 7861–7865 (2005).

    Article  CAS  PubMed  Google Scholar 

  137. Moritz, T., Mackay, W., Glassner, B. J., Williams, D. A. & Samson, L. Retrovirus-mediated expression of a DNA repair protein in bone marrow protects hematopoietic cells from nitrosourea-induced toxicity in vitro and in vivo. Cancer Res. 55, 2608–2614 (1995).

    CAS  PubMed  Google Scholar 

  138. Maze, R. et al. Increasing DNA repair methyltransferase levels via bone marrow stem cell transduction rescues mice from the toxic effects of 1,3-bis(2-chloroethyl)-1-nitrosourea, a chemotherapeutic alkylating agent. Proc. Natl Acad. Sci. USA 93, 206–210 (1996). References 137 and 138 show that transplantation of bone marrow cells overexpressing MGMT can suppress alkylating agent myelosuppression and toxicity in mice.

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  139. Jelinek, J. et al. Long-term protection of hematopoiesis against the cytotoxic effects of multiple doses of nitrosourea by retrovirus-mediated expression of human O6-alkylguanine-DNA-alkyltransferase. Blood 87, 1957–1961 (1996).

    Article  CAS  PubMed  Google Scholar 

  140. Allay, J. A., Koç, O. N., Davis, B. M. & Gerson, S. L. Retroviral-mediated gene transduction of human alkyltransferase complementary DNA confers nitrosourea resistance to human hematopoietic progenitors. Clin. Cancer Res. 2, 1353–1359 (1996).

    CAS  PubMed  Google Scholar 

  141. Schambach, A. & Baum, C. Vector design for expression of O6-methylguanine-DNA methyltransferase in hematopoietic cells. DNA Repair 6, 1187–1196 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  142. Neff, T. et al. Methylguanine methyltransferase–mediated in vivo selection and chemoprotection of allogeneic stem cells in a large-animal model. J. Clin. Invest. 112, 1581–1588 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  143. Maze, R., Hanenberg, H. & Williams, D. A. Establishing chemoresistance in hematopoietic progenitor cells. Mol. Med. Today 3, 350–358 (1997).

    Article  CAS  PubMed  Google Scholar 

  144. Ragg, S., Xu-Welliver, M. & Bailey, J. Direct reversal of DNA damage by mutant methyltransferase protein protects mice against dose-intensified chemotherapy and leads to in vivo selection of hematopoietic stem cells. Cancer Res. 60, 5187–5195 (2000).

    CAS  PubMed  Google Scholar 

  145. Jansen, M. et al. Hematoprotection and enrichment of transduced cells in vivo after gene transfer of MGMTP140K into hematopoietic stem cells. Cancer Gene Ther. 9, 737–746 (2002).

    Article  CAS  PubMed  Google Scholar 

  146. Neff, T. et al. Polyclonal chemoprotection against temozolomide in a large-animal model of drug resistance gene therapy. Blood 105, 997–1002 (2005).

    Article  CAS  PubMed  Google Scholar 

  147. Reha-Krantz, L. J., Nonay, R. L., Day, R. S. & Wilson, S. H. Replication of O6-methylguanine-containing DNA by repair and replicative DNA polymerases. J. Biol. Chem. 271, 20088–20095 (1996).

    Article  CAS  PubMed  Google Scholar 

  148. Haracska, L., Prakash, S. & Prakash, L. Replication past O6-methylguanine by yeast and human DNA polymerase eta. Mol. Cell. Biol. 20, 8001–8007 (2000).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  149. Choi, J. Y. et al. Translesion synthesis across O6-alkylguanine DNA adducts by recombinant human DNA polymerases. J. Biol. Chem. 281, 38244–38256 (2006).

    Article  CAS  PubMed  Google Scholar 

  150. Takenaka, K. et al. Involvement of vertebrate Polκ in translesion DNA synthesis across DNA monoalkylation damage. J. Biol. Chem. 281, 2000–2004 (2006).

    Article  CAS  PubMed  Google Scholar 

  151. Haracska, L., Prakash, S. & Prakash, L. Yeast DNA polymerase ζ is an efficient extender of primer ends opposite from 7,8-dihydro-8-oxoguanine and O6-methylguanine. Mol. Cell. Biol. 23, 1453–1459 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  152. Haracska, L., Prakash, L. & Prakash, S. Role of human DNA polymerase κ as an extender in translesion synthesis. Proc. Natl Acad. Sci. USA 99, 16000–16005 (2002).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  153. Kaina, B., Gerhard, F., Sankar, M. & Coquerelle, T. Transfection and expression of human O6-methylguanine-DNA methyltransferase (MGMT) cDNA in Chinese hamster cells: the role of MGMT in protection against the genotoxic effects of alkylating agents. Carcinogenesis 12, 1857–1867 (1991).

    Article  CAS  PubMed  Google Scholar 

  154. Lips, J. & Kaina, B. Repair of O6-methylguanine is not affected by thymine base pairing and the presence of MMR proteins. DNA Repair 487, 59–66 (2001).

    Article  CAS  Google Scholar 

  155. Casorelli I, Russo MT & M., B. Role of mismatch repair and MGMT in response to anticancer therapies. Anticancer Agents Med. Chem. 8, 368–380 (2008).

    Article  CAS  PubMed  Google Scholar 

  156. Duckett, D. R. et al. Human MutSα recognizes damaged DNA base pairs containing O6-methylguanine, O4-methylthymine, or the cisplatin-d(GpG) adduct. Proc. Natl Acad. Sci. USA 93, 6443–6447 (1996).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  157. Meikrantz, W., Bergom, M. A., Memisoglu, A. & Samson, L. O6-alkylguanine DNA lesions trigger apoptosis. Carcinogenesis 19, 369–372 (1998).

    Article  CAS  PubMed  Google Scholar 

  158. Rasmussen, L. J. & Samson, L. The Escherichia coli MutS DNA mismatch binding protein specifically binds O6-methylguanine DNA lesions. Carcinogenesis 17, 2085–2088 (1996). References 156 and 158 provide a direct link between the MMR pathway and alkylation damage by showing that MUTS and MUTSα can directly recognize O6meG lesions.

    Article  CAS  PubMed  Google Scholar 

  159. Dosch, J., Christmann, M. & Kaina, B. Mismatch G-T binding activity and MSH2 expression is quantitatively related to sensitivity of cells to methylating agents. Carcinogenesis 19, 567–573 (1998).

    Article  CAS  PubMed  Google Scholar 

  160. Hickman, M. J. & Samson, L. D. Role of DNA mismatch repair and p53 in signaling induction of apoptosis by alkylating agents. Proc. Natl Acad. Sci. USA 96, 10764–10769 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  161. Mojas, N., Lopes, M. & Jiricny, J. Mismatch repair-dependent processing of methylation damage gives rise to persistent single-stranded gaps in newly replicated DNA. Genes Dev. 21, 3342–3355 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  162. Ochs, K. & Kaina, B. Apoptosis induced by DNA damage O6-methylguanine is Bcl-2 and caspase-9/3 regulated and Fas/caspase-8 independent. Cancer Res. 60, 5815–5824 (2000). References 161 and 162 provide evidence that MMR-dependent processing of O6meG gives rise to cytotoxic DSBs that trigger apoptotic cell death.

    CAS  PubMed  Google Scholar 

  163. Rajesh, P., Rajesh, C., Wyatt, M. D. & Pittman, D. L. RAD51D protects against MLH1-dependent cytotoxic responses to O6-methylguanine. DNA Repair 9, 458–467 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  164. Roos, W. P. et al. Brca2/Xrcc2 dependent HR, but not NHEJ, is required for protection against O6-methylguanine triggered apoptosis, DSBs and chromosomal aberrations by a process leading to SCEs. DNA Repair 8, 72–86 (2009).

    Article  CAS  PubMed  Google Scholar 

  165. Cejka, P. & Jiricny, J. Interplay of DNA repair pathways controls methylation damage toxicity in saccharomyces cerevisiae. Genetics 179, 1835–1844 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  166. Mirzoeva, O. K., Kawaguchi, T. & Pieper, R. O. The Mre11/Rad50/Nbs1 complex interacts with the mismatch repair system and contributes to temozolomide-induced G2 arrest and cytotoxicity. Mol. Cancer Ther. 5, 2757–2766 (2006).

    Article  CAS  PubMed  Google Scholar 

  167. Tsaryk, R., Fabian, K., Thacker, J. & Kaina, B. Xrcc2 deficiency sensitizes cells to apoptosis by MNNG and the alkylating anticancer drugs temozolomide, fotemustine and mafosfamide. Cancer Lett. 239, 305–313 (2006).

    Article  CAS  PubMed  Google Scholar 

  168. Eich, M., Roos, W. P., Dianov, G. L., Digweed, M. & Kaina, B. Nijmegen breakage syndrome protein (NBN) causes resistance to methylating anticancer drugs such as temozolomide. Mol. Pharmacol. 78, 943–951 (2010).

    Article  CAS  PubMed  Google Scholar 

  169. Kaina, B. The interrelationship between SCE induction, cell survival, mutagenesis, aberration formation and DNA synthesis inhibition in V79 cells treated with N-methyl-N-nitrosourea or N-methyl-N'-nitro-N-nitrosoguanidine. Mutat. Res. 142, 49–54 (1985).

    Article  CAS  PubMed  Google Scholar 

  170. Yoshioka, K.-i., Yoshioka, Y. & Hsieh, P. ATR kinase activation mediated by MutSα and MutLα in response to cytotoxic O6-methylguanine adducts. Mol. Cell 22, 501–510 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  171. Branch, P., Aquilina, G., Bignami, M. & Karran, P. Defective mismatch binding and a mutator phenotype in cells tolerant to DNA damage. Nature 362, 652–654 (1993).

    Article  CAS  PubMed  Google Scholar 

  172. Koi, M. et al. Human chromosome 3 corrects mismatch repair deficiency and microsatellite instability and reduces N-methyl-N'-nitro-N-nitrosoguanidine tolerance in colon tumor cells with homozygous hMLH1 mutation. Cancer Res. 54, 4308–4312 (1994).

    CAS  PubMed  Google Scholar 

  173. de Wind, N., Dekker, M., Berns, A., Radman, M. & te Riele, H. Inactivation of the mouse Msh2 gene results in mismatch repair deficiency, methylation tolerance, hyperrecombination, and predisposition to cancer. Cell 82, 321–330 (1995). References 171–173 show that loss of MMR confers resistance to alkylating agent toxicity in both cells and animals, providing conclusive evidence for the hypothesis that inappropriate MMR-dependent processing of O6meG is a major cytotoxic event associated with alkylating agents.

    Article  CAS  PubMed  Google Scholar 

  174. Andrew, S. E. et al. Tissues of MSH2-deficient mice demonstrate hypermutability on exposure to a DNA methylating agent. Proc. Natl Acad. Sci. USA 95, 1126–1130 (1998).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  175. Hickman, M. J. & Samson, L. D. Apoptotic signaling in response to a single type of DNA lesion, O6-methylguanine. Mol. Cell 14, 105–116 (2004).

    Article  CAS  PubMed  Google Scholar 

  176. Toft, N. J. et al. Msh2 status modulates both apoptosis and mutation frequency in the murine small intestine. Proc. Natl Acad. Sci. USA 96, 3911–3915 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  177. Sansom, O. J., Toft, N. J., Winton, D. J. & Clarke, A. R. Msh-2 suppresses in vivo mutation in a gene dose and lesion dependent manner. Oncogene 20, 3580–3584 (2001).

    Article  CAS  PubMed  Google Scholar 

  178. Sansom, O. J. & Clarke, A. R. The ability to engage enterocyte apoptosis does not predict long-term crypt survival in p53 and Msh2 deficient mice. Oncogene 21, 5934–5939 (2002).

    Article  CAS  PubMed  Google Scholar 

  179. Reese, J. S., Liu, L. & Gerson, S. L. Repopulating defect of mismatch repair-deficient hematopoietic stem cells. Blood 102, 1626–1633 (2003).

    Article  CAS  PubMed  Google Scholar 

  180. Sansom, O. J. et al. Apoptosis and mutation in the murine small intestine: loss of Mlh1- and Pms2-dependent apoptosis leads to increased mutation in vivo. DNA Repair 2, 1029–1039 (2003).

    Article  CAS  PubMed  Google Scholar 

  181. Bugni, J. M., Meira, L. B. & Samson, L. D. Alkylation-induced colon tumorigenesis in mice deficient in the Mgmt and Msh6 proteins. Oncogene 28, 734–741 (2009).

    Article  CAS  PubMed  Google Scholar 

  182. Kawate, H. et al. A defect in a single allele of the Mlh1 gene causes dissociation of the killing and tumorigenic actions of an alkylating carcinogen in methyltransferase-deficient mice. Carcinogenesis 21, 301–305 (2000).

    Article  CAS  PubMed  Google Scholar 

  183. Stallons, L. J. & McGregor, W. G. Translesion synthesis polymerases in the prevention and promotion of carcinogenesis. J. Nucleic Acids 2010, 1–10 (2010).

    Article  CAS  Google Scholar 

  184. Moynahan, M. E. & Jasin, M. Mitotic homologous recombination maintains genomic stability and suppresses tumorigenesis. Nature Rev. Mol. Cell Biol. 11, 196–207 (2010).

    Article  CAS  Google Scholar 

  185. Arana, M. E. & Kunkel, T. A. Mutator phenotypes due to DNA replication infidelity. Semin. Cancer Biol. 20, 304–311 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  186. Hewish, M., Lord, C. J., Martin, S. A., Cunningham, D. & Ashworth, A. Mismatch repair deficient colorectal cancer in the era of personalized treatment. Nature Rev. Clin. Oncol. 7, 197–208 (2010).

    Article  Google Scholar 

  187. Trainer, A. H. et al. The role of BRCA mutation testing in determining breast cancer therapy. Nature Rev. Clin. Oncol. 7, 708–717 (2010).

    Article  CAS  Google Scholar 

  188. Valeri, N. et al. Modulation of mismatch repair and genomic stability by miR-155. Proc. Natl Acad. Sci. USA 107, 6982–6987 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  189. Moskwa, P. et al. miR-182-mediated downregulation of BRCA1 impacts DNA repair and sensitivity to PARP inhibitors. Mol. Cell 41, 210–220 (2011). This study shows that microRNAs involved in the expression of DNA damage proteins could be modulated in combination with PARP inhibitors to affect sensitivity to alkylating agents.

    Article  CAS  PubMed  Google Scholar 

  190. Kiltie, A. E. (ed.) Molecular Epidemiology of DNA Repair Genes in Bladder Cancer (Humana Press, Bethesda, 2009).

    Book  Google Scholar 

  191. Fenske, T. S. et al. Identification of candidate alkylator-induced cancer susceptibility genes by whole genome scanning in mice. Cancer Res. 66, 5029–5038 (2006).

    Article  CAS  PubMed  Google Scholar 

  192. Lutz, W. A true threshold dose in chemical carcinogenesis cannot be defined for a population, irrespective of the mode of action. Hum. Exp. Toxicol. 19, 566–568 (2000).

    Article  CAS  PubMed  Google Scholar 

  193. Fry, R. C. et al. Genomic predictors of interindividual differences in response to DNA damaging agents. Genes Dev. 22, 2621–2626 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  194. Begley, T. J., Rosenbach, A. S., Ideker, T. & Samson, L. D. Hot spots for modulating toxicity identified by genomic phenotyping and localization mapping. Mol. Cell 16, 117–125 (2004).

    Article  CAS  PubMed  Google Scholar 

  195. Ravi, D. et al. A network of conserved damage survival pathways revealed by a genomic RNAi screen. PLoS Genet. 5, e1000527 (2009).

    Article  PubMed  PubMed Central  CAS  Google Scholar 

  196. McKinnon, P. J. DNA repair deficiency and neurological disease. Nature Rev. Neurosci. 10, 100–112 (2009).

    Article  CAS  Google Scholar 

  197. Robbins JH, Kraemer KH, Lutzner MA, Festoff BW & HG., C. Xeroderma pigmentosum. An inherited diseases with sun sensitivity, multiple cutaneous neoplasms, and abnormal DNA repair. Ann. Intern. Med. 80, 221–248 (1974).

    Article  CAS  PubMed  Google Scholar 

  198. Savitsky, K. et al. A single ataxia telangiectasia gene with a product similar to PI-3 kinase. Science 268, 1749–1753 (1995).

    Article  CAS  PubMed  Google Scholar 

  199. Lovell, M. A., Xie, C. & Markesbery, W. R. Decreased base excision repair and increased helicase activity in Alzheimer's disease brain. Brain Res. 855, 116–123 (2000).

    Article  CAS  PubMed  Google Scholar 

  200. Weissman, L., de Souza-Pinto, N. C., Mattson, M. P. & Bohr, V. A. DNA base excision repair activities in mouse models of Alzheimer's disease. Neurobiol. Aging 30, 2080–2081 (2009).

    Article  CAS  PubMed  Google Scholar 

  201. Iida, T., Furuta, A., Nishioka, K., Nakabeppu, Y. & Iwaki, T. Expression of 8-oxoguanine DNA glycosylase is reduced and associated with neurofibrillary tangles in Alzheimer's disease brain. Acta Neuropathol. 103, 20–25 (2002).

    Article  CAS  PubMed  Google Scholar 

  202. Weissman, L. et al. Defective DNA base excision repair in brain from individuals with Alzheimer's disease and amnestic mild cognitive impairment. Nucleic Acids Res. 35, 5545–5555 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  203. Hegde, M. L., Hazra, T. K. & Mitra, S. Early steps in the DNA base excision/single-strand interruption repair pathway in mammalian cells. Cell Res. 18, 27–47 (2008).

    Article  CAS  PubMed  Google Scholar 

  204. Zecca, L., Youdim, M. B. H., Riederer, P., Connor, J. R. & Crichton, R. R. Iron, brain ageing and neurodegenerative disorders. Nature Rev. Neurosci. 5, 863–873 (2004).

    Article  CAS  Google Scholar 

  205. Interthal, H. et al. SCAN1 mutant Tdp1 accumulates the enzyme-DNA intermediate and causes camptothecin hypersensitivity. EMBO J. 24, 2224–2233 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  206. El-Khamisy, S. F. et al. Defective DNA single-strand break repair in spinocerebellar ataxia with axonal neuropathy-1. Nature 434, 108–113 (2005). This important paper was the first to link SSB repair with neurodegeneration.

    Article  CAS  PubMed  Google Scholar 

  207. Lee, Y. et al. The genesis of cerebellar interneurons and the prevention of neural DNA damage require XRCC1. Nature Neurosci. 12, 973–980 (2009).

    Article  CAS  PubMed  Google Scholar 

  208. Lauritzen, K. H. et al. Mitochondrial DNA toxicity in forebrain neurons causes apoptosis, neurodegeneration, and impaired behavior. Mol. Cell. Biol. 30, 1357–1367 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  209. Liu, L., Qin, X. & Gerson, S.L. Reduced lung tumorigenesis in human methylguanine DNA — methyltransferase transgenic mice achieved by expression of transgene within target cell. Carcinogenesis 20, 279–284 (1999).

    Article  CAS  PubMed  Google Scholar 

Download references

Acknowledgements

The authors would like to thank members of the Samson Laboratory and C.-L. Fu for critical reading of this manuscript. The authors have been supported by US National Institutes of Health grants CA055042, CA075576, CA149261, CA112967, DP1-OD006422 and ES002109. D.F. was supported by an American Cancer Society Postdoctoral Fellowship and L.D.S. is an American Cancer Society Research Professor.

Author information

Authors and Affiliations

  1. Departments of Biological Engineering and Biology, Center for Environmental Health Sciences, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, 02139, Massachusetts, USA

    Dragony Fu, Jennifer A. Calvo & Leona D. Samson

Authors
  1. Dragony Fu
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Jennifer A. Calvo
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Leona D. Samson
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to Leona D. Samson.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

Related links

Glossary

Alkyl

Chemical sidechain that consists only of single-bonded carbon and hydrogen atoms; for example, a methyl or an ethyl group.

Nucleophilic substitution

Chemical bonding reaction between an electron pair donor (nucleophile) with an electron pair acceptor (electrophile).

Chloroethyl

Alkyl functional group consisting of a chlorine atom bonded to an ethyl carbon group.

Depurination

Loss of a purine base (adenine or guanine) from the DNA backbone through chemical or enzymatic hydrolysis.

Clastogenic

The ability to disrupt or to break chromosomes.

Sister chromatid exchanges

(SCEs). Crossing-over event between sister chromatids, leading to the exchange of homologous stretches of DNA sequence.

Microsatellite instability

Mutations in short motifs of tandemly repeated nucleotides that result from replication slippage and deficient mismatch repair.

Pancytopenia

Severe reduction in the number of all blood cell types, including red and white blood cells and platelets.

Myelosuppression

Inhibition of blood cell production in the bone marrow.

Apoptosis

A type of caspase-dependent programmed cell death that is characterized by cell blebbing and DNA fragmentation.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Fu, D., Calvo, J. & Samson, L. Balancing repair and tolerance of DNA damage caused by alkylating agents. Nat Rev Cancer 12, 104–120 (2012). https://doi.org/10.1038/nrc3185

Download citation

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/nrc3185

This article is cited by

Search

Advanced search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing