title: Silencing of BNIP3 results from promoter methylation by DNA methyltransferase 1 induced by the mitogen-activated protein kinase pathway.
abstract: We have previously shown that Ras mediates NO-induced BNIP3 expression via the MEK-E RK-HIF-1 pathway i n mouse macrophages, and that NO-induced death results at least in part from the induction of BNIP3. In the present study, we describe another aspect of Ras regulation of BNIP3 expression in pancreatic cancer cells. Human BNIP3 promoter-driven luciferase activity was efficiently induced by activated Ras in AsPC-1, Miapaca-2, PK-1 and PANC-1 cells. However, expression of endogenous BNIP3 was not induced, and BNIP3 up-regulation by hypoxia was also inhibited. Treatment of the cells with the DNMT inhibitor, 5-aza-2-deoxycytidine, restored BNIP3 induction, indicating that DNA methylation of the BNIP3 promoter was responsible for the inhibition of BNIP3 induction. Furthermore, inhibition of the MEK pathway with U0126 reduced DNMT1 expression, but not that of DNMT3a and 3b, and restored the hypoxia-inducibility of BNIP3, suggesting that the DNA methylation of the BNIP3 promoter was mediated by DNMT1 via the MEK pathway.
authors.affiliation: Department of Biology, College of Biological Sciences and Biotechnology, Chungnam National University, Daejeon, 305-764, Korea.
authors.forename: Hyun-Jung
authors.initials: HJ
authors.lastname: An
authors.forename: Hayyoung
authors.initials: H
authors.lastname: Lee
authors.forename: Sang-Gi
authors.initials: SG
authors.lastname: Paik
mesh_terms: D001374:Azacitidine / Q000031:analogs & derivatives / Q000494:pharmacology; D002070:Butadienes / Q000494:pharmacology; D015687:Cell Hypoxia; D045744:Cell Line, Tumor; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D019175:DNA Methylation; D000077209:Decitabine; D044127:Epigenesis, Genetic; D017930:Genes, Reporter; D006801:Humans; D049410:Luciferases, Renilla / Q000096:biosynthesis / Q000235:genetics; D020935:MAP Kinase Signaling System / Q000187:drug effects; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism; D009570:Nitriles / Q000494:pharmacology; D011401:Promoter Regions, Genetic; D011518:Proto-Oncogene Proteins / Q000235:genetics* / Q000378:metabolism; D016283:Proto-Oncogene Proteins p21(ras) / Q000378:metabolism; D014158:Transcription, Genetic / Q000187:drug effects
chemical_list: C090121:BNIP3 protein, human; D002070:Butadienes; D008565:Membrane Proteins; D009570:Nitriles; D011518:Proto-Oncogene Proteins; C113580:U 0126; D000077209:Decitabine; D049410:Luciferases, Renilla; D000076123:DNA (Cytosine-5-)-Methyltransferase 1; D004248:DNA (Cytosine-5-)-Methyltransferases; C000619380:DNMT1 protein, human; C000619381:Dnmt1 protein, mouse; D020928:Mitogen-Activated Protein Kinases; D016283:Proto-Oncogene Proteins p21(ras); D001374:Azacitidine