Epigenetic silencing of E- and P-cadherin gene expression in human melanoma cell lines.
The degree of E- and P-cadherin expressions inversely correlate with the progression stage of human melanoma. In the present study, we analyzed mechanisms of down-regulation of E- and P-cadherin gene expressions in 8 human melanoma cell lines. In 5 of the 8 melanoma cell lines, E-cadherin expression was lost or markedly decreased compared to that in normal melanocytes, and 4 of the 5 melanoma cell lines lost P-cadherin expression. All of the melanoma cell lines expressed snail, which is known to encode a transcription repressor for E-cadherin, at a higher level than melanocytes whereas expression levels of the snail varied among cell lines. Transduction of snail gene into MMAc cells which expressed a high level of E-cadherin and an extremely low level of snail decreased expression of E-cadherin but not P-cadherin. In contrast, transduction of antisense-snail gene into A375M cells which expressed no E-cadherin and a high level of snail restored expression of E-cadherin but not P-cadherin. Methylation-specific PCR analysis revealed CpG methylation in the promoter region of E-cadherin of MeWo and AKI cells. Further, the treatment with a demethylating agent, 5-azacytidine led AKI and A375M cells to re-express both E- and P-cadherin. The results show E-cadherin gene is silenced by at least two distinct mechanisms (methylation and transrepression by Snail) in human melanoma cell lines whereas P-cadherin gene seems to be silenced by methylation but not by snail.
Tsutsumida
Arata
A
Division of Cancer-Related Genes, Institute for Genetic Medicine, Hokkaido University, Kita-15, Nishi-7, Kita-ku, Sapporo 060-0815, Japan.
Hamada
Jun-ichi
J
Tada
Mitsuhiro
M
Aoyama
Tetsuya
T
Furuuchi
Keiji
K
Kawai
Yoshiko
Y
Yamamoto
Yuhei
Y
Sugihara
Tsuneki
T
Moriuchi
Tetsuya
T
D015820:Cadherins / Q000096:biosynthesis*; D019175:DNA Methylation; D004268:DNA-Binding Proteins / Q000494:pharmacology; D015536:Down-Regulation; D020869:Gene Expression Profiling; D020868:Gene Silencing; D006801:Humans; D008545:Melanoma / Q000235:genetics* / Q000473:pathology*; D011401:Promoter Regions, Genetic; D012878:Skin Neoplasms / Q000235:genetics* / Q000473:pathology*; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors / Q000494:pharmacology; D014407:Tumor Cells, Cultured; D016335:Zinc Fingers
D015820:Cadherins; D004268:DNA-Binding Proteins; D000071250:Snail Family Transcription Factors; D014157:Transcription Factors