Gemcitabine functions epigenetically by inhibiting repair mediated DNA demethylation.
Gemcitabine is a cytotoxic cytidine analog, which is widely used in anti-cancer therapy. One mechanism by which gemcitabine acts is by inhibiting nucleotide excision repair (NER). Recently NER was implicated in Gadd45 mediated DNA demethylation and epigenetic gene activation. Here we analyzed the effect of gemcitabine on DNA demethylation. We find that gemcitabine inhibits specifically Gadd45a mediated reporter gene activation and DNA demethylation, similar to the topoisomerase I inhibitor camptothecin, which also inhibits NER. In contrast, base excision repair inhibitors had no effect on DNA demethylation. In Xenopus oocytes, gemcitabine inhibits DNA repair synthesis accompanying demethylation of oct4. In mammalian cells, gemcitabine induces DNA hypermethylation and silencing of MLH1. The results indicate that gemcitabine induces epigenetic gene silencing by inhibiting repair mediated DNA demethylation. Thus, gemcitabine can function epigenetically and provides a tool to manipulate DNA methylation.
Division of Molecular Embryology, DKFZ-ZMBH Alliance, Deutsches Krebsforschungszentrum, Heidelberg, Germany.
Andrea
A
Schäfer
Lars
L
Schomacher
Guillermo
G
Barreto
Gabi
G
Döderlein
Christof
C
Niehrs
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D000818:Animals; D000964:Antimetabolites, Antineoplastic / Q000494:pharmacology; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D045744:Cell Line, Tumor; D019175:DNA Methylation / Q000187:drug effects*; D004260:DNA Repair / Q000187:drug effects*; D003841:Deoxycytidine / Q000031:analogs & derivatives* / Q000494:pharmacology; D044127:Epigenesis, Genetic / Q000187:drug effects; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D045325:HCT116 Cells; D057809:HEK293 Cells; D006801:Humans; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D009865:Oocytes / Q000187:drug effects / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014981:Xenopus; D029867:Xenopus Proteins / Q000235:genetics / Q000378:metabolism; D000093542:Gemcitabine; D000097642:GADD45 Proteins
D048868:Adaptor Proteins, Signal Transducing; D000964:Antimetabolites, Antineoplastic; D018797:Cell Cycle Proteins; D003841:Deoxycytidine; D000070957:MutL Protein Homolog 1; D009687:Nuclear Proteins; D029867:Xenopus Proteins; D000093542:Gemcitabine; C517171:Gadd45a protein, Xenopus; D000097642:GADD45 Proteins; C501486:MLH1 protein, human