Search. Read. Cite.

Easy to search. Easy to read. Easy to cite with credible sources.

Carcinogenesis

Year: 2010  |  Volume: 31  |  Issue: 7  |  Page No.: 1194 - 1201

Modulation of E-cadherin expression by K-Ras; involvement of DNA methyltransferase-3b

O Kwon, S. J Jeong, S. O Kim, L He, H. G Lee, K. L Jang, H Osada, M Jung, B. Y Kim and J. S. Ahn

Abstract

E-cadherin, as a tumor suppressor, plays an important role for intercellular adhesion involved in metastasis. Although K-Ras is highly expressed in a variety of cancers, the regulation of E-cadherin expression by K-Ras in association with DNA methylation and cell metastasis has not been completely clarified. In this study, E-cadherin expression was repressed in 267B1/K-Ras human epithelial prostate cancer cells stably overexpressing K-Ras, resulting from hypermethylation of E-cadherin promoter as evidenced by methylation-specific polymerase chain reaction (PCR), bisulfite sequencing, real-time reverse transcription–PCR and western blot analysis. The increased level of DNA methyltransferase (DNMT) 3b in 267B1/K-Ras cells was reduced by small interfering RNA-mediated knockdown of k-ras, whereas DNMT1 and DNMT3a did not change regardless of K-Ras or 5-aza-2'-deoxycytidine (5'-AzaC) treatment. Furthermore, binding of DNMT3b to E-cadherin promoter was increased in 267B1/K-Ras cells but was reduced by 5'-AzaC, as revealed by chromatin immunoprecipitation assay, which was in agreement with cell aggregation and invasive mobilization of the cells. Hence, our data suggest that increased binding of DNMT3b to E-cadherin promoter region by K-Ras cause promoter hypermethylation for reduced expression of E-cadherin, leading to the decreased cell aggregation and increased metastasis of human prostate cancer cells overexpressing K-Ras.

View Fulltext