Epigenetic silencing of E- and P-cadherin gene expression in human melanoma cell lines.
Epigenetic silencing of E- and P-cadherin gene expression in human melanoma cell lines.
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DOI：
10.3892/ijo.25.5.1415
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发表时间：
2004-11
影响因子：
5.2
通讯作者：
A. Tsutsumida;J. Hamada;M. Tada;T. Aoyama;K. Furuuchi;Y. Kawai;Yuhei Yamamoto;T. Sugihara;T. Moriuchi
中科院分区：
文献类型：
--
作者：
A. Tsutsumida;J. Hamada;M. Tada;T. Aoyama;K. Furuuchi;Y. Kawai;Yuhei Yamamoto;T. Sugihara;T. Moriuchi
E-和P-cadherin的表达程度与人类黑色素瘤的进展阶段呈负相关。在本研究中，我们分析了8种人黑色素瘤细胞系中E-和P-cadherin基因表达下调的机制。与正常黑色素细胞相比，8个黑色素瘤细胞系中有5个E-cadherin表达缺失或明显降低，5个黑色素瘤细胞系中有4个P-cadherin表达缺失。所有黑色素瘤细胞系都比黑素细胞表达更高水平的蜗牛蛋白，而蜗牛蛋白的表达水平在不同细胞系中有所不同。众所周知，蜗牛蛋白编码e -钙粘蛋白的转录抑制因子。将蜗牛基因转导到表达高水平E-cadherin和极低水平蜗牛的MMAc细胞中，可降低E-cadherin的表达，但不影响P-cadherin的表达。相反，将反义蜗牛基因转导到不表达E-cadherin和高水平蜗牛的A375M细胞中，可以恢复E-cadherin的表达，但不能恢复P-cadherin的表达。甲基化特异性PCR分析显示，MeWo和AKI细胞E-cadherin启动子区存在CpG甲基化。此外，用去甲基化剂5-氮杂胞苷处理后，AKI和A375M细胞重新表达E-和P-cadherin。结果表明，E-cadherin基因在人黑色素瘤细胞系中至少通过两种不同的机制（甲基化和蜗牛转抑制）沉默，而P-cadherin基因似乎通过甲基化沉默，而不是通过蜗牛沉默。
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.