新型肿瘤标志物MEF2D在肝癌侵袭转移中的作用

The role of novel tumor marker MEF2D in invasion and metastasis of hepatocellular carcinoma

目的验证MEF2D参与TGF-β诱导EMT过程并且可以促进肝癌细胞的侵袭转移,判断MEF2D是否可以作为肝癌肿瘤发生和转移的分子诊断标志物。方法采用不同浓度的TGF-β处理PLC/PRF5细胞,观察细胞发生EMT的细胞形态,MEF2D以及EMT标记蛋白的表达量变化;通过敲除或过表达MEF2D观察对肝癌细胞侵袭转移的影响;对肝癌转移病人基因芯片的分析和对临床样本检测MEF2D的表达量。结果基因芯片GDS4269的分析结果与细胞实验一致,TGF-β诱导EMT发生,MEF2D表达量明显升高;过表达MEF2D细胞迁移能力增加,下调MEF2D细胞的侵袭能力明显下降;免疫组化结果显示肿瘤中MEF2D表达量高于癌旁组织,转移灶肿瘤中MEF2D的表达量明显高于原发灶肿瘤,肝癌转移基因芯片GDS3091也显示MEF2D在转移瘤中高表达。结论 MEF2D参与TGF-β诱导的EMT过程并且MEF2D可以促进细胞的侵袭转移,结合临床标本可以初步得出结论 MEF2D具有作为肝癌发生和转移的诊断标志物的价值。

Objective： To study the potential biomarker of MEF2D for the occurrence and metasis of hepatocellular carcinoma（ HCC） in the processes of TGF-β-induced EMT,invasion and metastasis of HCC cells. Methods： PLC/PRF5 cells were treated with TGF-βat different concentrations and cell morphology changes were observed during the process of EMT by microscope; the expression level of MEF2D and EMT markers were detected by immunoblotting; knockdown and overexpression of MEF2D were adopted to explore the invasion and metastasis of cells respectively; gene chip and immunohistochemistry（ IHC） were used to uncover the expression of MEF2D in patient tumor samples. Results： The expression level of MEF2D increased significantly in TGF-β-induced EMT of PLC/PRF5 cells; overexpression of MEF2D promoted cell migration and knockdown of MEF2D reduced the capability of invasion. Both gene chip GDS4269 and the metastasis gene chip GDS3091 showed high expression level of MEF2D in clinical tumor samples. IHC data also revealed that the expression level of MEF2D in metastatic tumors was significantly higher than that in primary tumors. Conclusion： MEF2D plays a role in the process of TGF-β-induced EMT,invasion and metastasis of HCC cells. Combined with data from clinical specimens,MEF2D can be a promising biomarker for the occurrence and metastasis of hepatocellular carcinoma.