转录因子Snail调控上皮-间质转型及对肿瘤转移的逆转作用

Effect of Transcriptional Factor Snail on Epithelial-Mesenchymal Transition and Tumor Metastasis

背景与目的:研究表明转录因子Snail调控上皮-间质转型(epithelialtomesenchymaltransition,EMT)与肿瘤转移有一定的相关性。本研究通过观察Snail促进EMT以及反义Snail对肿瘤细胞EMT的逆转,明确Snail在肿瘤转移中的作用。方法:分别以SnailcDNA转染MDCK细胞,反义Snail转染MDA-MB231细胞。Westernblot法检测上皮性标记基因上皮钙粘附素(E-cadherin)、β-连环素(β-catenin)、角蛋白18(Cytokeratin18)与间质性标记基因纤粘蛋白(Fibronectin)及转移相关基因基质金属蛋白酶-2(MMP-2)、RhoA蛋白的改变;细胞划痕实验、Boyden小室体外侵袭实验反映细胞转移潜能的变化。结果:转染SnailcDNA的MDCK细胞,上皮标记基因E-cadherin、β-catenin、Cytokeratin18蛋白表达下调,而间质及转移相关基因Fibronectin、MMP-2、RhoA蛋白表达增强(P<0.05);细胞体外运动力与侵袭力增加(P<0.05);反义Snail转染MDA-MB231细胞后,其实验结果与经SnailcDNA处理后的MDCK细胞相反。结论:Snail能促进正常上皮细胞发生EMT,拮抗肿瘤细胞Snail的表达可逆转EMT表型、降低肿瘤转移潜能。

BACKGROUND ＆ OBJECTIVE： Transcription factor Snail mediates epithelial-mesenchymal transition （EMT）, and is associated with tumor metastasis. This study was designed to observe the enhancive effect of Snail and the reverse effect of antisense-Snail on EMT of tumor cells, and explore the role of Snail in tumor metastasis. METHODS. Snail cDNA was transfected into canine renal epithelial cell line MDCK; antisense-Snail was transfected into human breast cancer cell line MDA-MB231. The expression of epithelial markers E-cadherin, β-catenin and Cytokeratin 18, mesenchymal marker Fibronectin, metastasis-related marker matrix metalloproteinase-2 （MMP-2）, and RhoA were detected by Western blot. The metastatic potential of tumor cells was examined by in vitro cell wound model and Boyden chamber invasion assay. RESULTS.The invasion potential of MDCK cells was enhanced after transfection of Snail. The expression of E-cadherin, β-catenin, and Cytokeratin 18 was significantly lower in Snail-transfected MDCK cells than in control cells （P〈0.05）; the expression of Fibronectin, MMP-2, and RhoA was significantly higher in Snail-transfected cells than in control cells （P〈0.05）. Inhibiting the expression of Snail with antisense-Snail in MDA- MB231 cells led to opposite results. CONCLUSION： Snail promotes EMT in normal epithelial cells, and inhibiting the expression of Snail may reverse EMT and suppress tumor metastasis.