DNA-Methyltransferases (DNMT) knockouts

Alterations in DNA-methylation are a hallmark of human tumor cells. DNMT1 is expressed in three different splice variants and exhibits considerable preference for hemimethylated DNA and is therefore referred to as the maintenance methylase. DNMT3b is generally considered to be responsible for de novo methylation during embryonic development and probably also during tumor development. Recent studies using somatic knock-out of DNA-methyltransferases have shown a reduction in overall methylation and a re-expression of tumor suppressor genes. Cells deficient of both, DNMT1 and DNMT3b may exhibit almost complete demethylation and growth suppression. In the present study, we performed MEK-inhibition via U0126 treatment for the wildtype and every DNMT-knockout to focus on MEK/RAS-target genes regulated by methylation. Keywords: genetic modification This series includes dual channel hybridizations of 14 independent HCT-116 cell line lysates on Unigene3.1 cDNA Arrays. In this series, five DNMT-wildtype, three DNMT1-KO, three DNMT3-KO and three DNMT1 and 3B double KO were included with different treatment status (none, DMSO, U0126, Aza-CdR). For every independent sample, two technical replicates were performed and further processed as mean values.