Epigenetic inactivation of the metastasis suppressor RECK enhances invasion of human colon cancer cells
Epigenetic inactivation of the metastasis suppressor RECK enhances invasion of human colon cancer cells
复制标题
DOI：
10.1002/jcp.21089
复制
发表时间：
2007-10-01
影响因子：
5.6
通讯作者：
Hung, Wen-Chun
中科院分区：
文献类型：
--
作者：
Cho, Chun-Yu;Wang, Jui-Ho;Hung, Wen-Chun
RECK基因是一种重要的转移抑制基因，在人结肠癌中表达下调。然而，这种下调的分子机制及其生物学意义仍不清楚。在本研究中，我们研究了RECK的下调是否是由通过启动子甲基化的表观遗传失活引起的，并测试了DNA甲基转移酶（DNMT）的作用对RECK表达和细胞侵袭的影响。比较结肠癌组织和正常结肠组织中RECK的mRNA和蛋白水平。我们发现，在分析的25个肿瘤中，48%的肿瘤中发现了RECK的下调。MSP分析显示，RECK基因启动子甲基化在44%（11/25）的肿瘤组织中检测到，并且发现下调与启动子甲基化之间存在强相关性（P = 0.028）。在SW 480和SW 620人结肠癌细胞系中也发现了启动子甲基化。DNA甲基转移酶（DNMT）抑制剂5 '-氮杂胞苷逆转了启动子甲基化，恢复了RECK表达，并抑制了这两种细胞系的侵袭。RECK的恢复对于5 '-氮杂胞苷介导的细胞侵袭抑制是关键的，因为特异性抗体对RECK的抑制显著减弱了5 '-氮杂胞苷的抗侵袭能力。总之，我们的研究结果表明，结肠癌中转移抑制因子RECK的下调与启动子甲基化有关，DNMT抑制剂可能会恢复RECK表达以抑制细胞侵袭。
Down-regulation of RECK, an important metastasis suppressor gene, has been found in human colon cancer. However, the molecular mechanism for this down-regulation and its biological significance are still unclear. In the present study, we investigated whether down-regulation of RECK is caused by epigenetic inactivation via promoter methylation and tested the effect of DNA methyltransferase (DNMT) inhibitoron RECK expression and cell invasion. The mRNA and protein levels of RECK in colon tumor tissues and their normal counterparts were compared. We found that down-regulation of RECK was found in 48% of the twenty five tumors analyzed. MSP analysis demonstrated that methylation of RECK promoter was detected in 44% (11/25) of the tumor tissues and a strong correlation between down-regulation and promoter methylation was found (P = 0.028). Promoter methylation was also found in SW480 and SW620 human colon cancer cell lines. DNA methytransferase (DNMT) inhibitor 5 '-azacytidine reversed promoter methylation, restored RECK expression and suppressed invasion by these two cell lines. Restoration of RECK is critical for 5 '-azacytidine-mediated suppression of cell invasion because inhibition of RECK by a specific antibody significantly attenuated the anti-invasive ability of 5 '-azacytidine. Taken together, our results suggest that down-regulation of the metastasis suppressor RECK in colon cancer is associated with promoter methylation and that a DNMT inhibitor may restore RECK expression to inhibit cell invasion.