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Methylation and Cancer MI616 Spring 2007 Andrew J. Pierce Microbiology, Immunology and Molecular Genetics Graduate Center for Toxicology Markey Cancer.

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Presentation on theme: "Methylation and Cancer MI616 Spring 2007 Andrew J. Pierce Microbiology, Immunology and Molecular Genetics Graduate Center for Toxicology Markey Cancer."— Presentation transcript:

1 Methylation and Cancer MI616 Spring 2007 Andrew J. Pierce Microbiology, Immunology and Molecular Genetics Graduate Center for Toxicology Markey Cancer Center University of Kentucky

2 Some considerations of methylation in cancer: cytosine methylation inactivating genes cytosine demethylation activating genes histone methylation in chromatin (eg. H3 lys4) response to methylating chemotherapy drugs temozolomideO 6 -methyl guanine

3 http://www.hscbklyn.edu/SUNY/Biochem/ALCOHOL/alcohol_folate_bkgd.html cytosine5-methylcytosine DNMT Single Carbon Transfers

4 5-methylcytosine Occurs on CpG sequences CpG is under-represented in the genome CpG is over-represented near promoter sequences reset at fertilization and established early in embryogenesis Clark SJ, Melki J. DNA methylation and gene silencing in cancer: which is the guilty party? Oncogene. 2002 Aug 12;21(35):5380-7.

5 G : 5-MeC A : T G : C Geometry of 5-methycytosine

6 Robertson KD. DNA methylation and chromatin - unraveling the tangled web. Oncogene. 2002 Aug 12;21(35):5361-79. Model for methyl-directed gene deactivation

7 Genes altered by cytosine methylation in cancer Rb (tumor supressor) Mlh1 (mismatch repair) VHL (oxidative stress response) p16 INK4A (CDK inhibitor) CpG island hypermethylation Inactivation Activation parasitic sequences eg: retrotransposons activate homologous recombination?

8 Esteller M. CpG island hypermethylation and tumor suppressor genes: a booming present, a brighter future. Oncogene. 2002 Aug 12;21(35):5427-40. Genes deactivated by methylation in human cancers

9 Esteller M. CpG island hypermethylation and tumor suppressor genes: a booming present, a brighter future. Oncogene. 2002 Aug 12;21(35):5427-40. 11 different tumor-supressor genes

10 Chemotherapy and reactivation of methylated genes cytidine analogs irreversibly bind DNMT’s leading to genome-wide demethylation Christman JK. 5-Azacytidine and 5-aza-2'-deoxycytidine as inhibitors of DNA methylation: mechanistic studies and their implications for cancer therapy. Oncogene. 2002 Aug 12;21(35):5483-95.

11 Christman JK. 5-Azacytidine and 5-aza-2'-deoxycytidine as inhibitors of DNA methylation: mechanistic studies and their implications for cancer therapy. Oncogene. 2002 Aug 12;21(35):5483-95.

12 Das PM, Singal R. DNA methylation and cancer. J Clin Oncol. 2004 Nov 15;22(22):4632-42. Methylation based cancer screening

13 Histone methylation Rice JC, Allis CD. Histone methylation versus histone acetylation: new insights into epigenetic regulation. Curr Opin Cell Biol. 2001 Jun;13(3):263-73.\

14 Shi Y, Lan F, Matson C, Mulligan P, Whetstine JR, Cole PA, Casero RA, Shi Y. Histone demethylation mediated by the nuclear amine oxidase homolog LSD1. Cell. 2004 Dec 29;119(7):941-53. A “real” histone demethylase

15 Methotrexate mediated inactivation of RAS?


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