Axin基因异常高甲基化对肺癌细胞生物学行为的调节

The regulatory effect of hypermethylated Axin gene on biological behavior of lung cancer cells

目的体轴抑制因子Axin是Wnt信号传导通路的关键抑制因子,本研究探讨部分肺癌细胞系中Axin表达下调的原因,及其表达下调对肺癌生物学行为的影响。方法应用甲基化特异性PCR(MSP)对BE1和SPC-A-1细胞系中Axin基因启动子区和第一内含子区的甲基化状态进行了检测,应用RT-PCR方法检测了两细胞系中AxinmRNA表达。利用野生型Axin质粒转染两种细胞,并且应用MTT和Transwell细胞侵袭实验观察两种细胞系在转染后细胞生物学行为的变化。结果 BE1细胞中Axin基因的启动子区和第一内含子区为高甲基化状态,而SPC细胞为非甲基化状态,BE1细胞中AxinmRNA的表达明显低于SPC细胞系(P<0.05),5-氮杂-2'-脱氧胞苷(5-Aza-2'-deoxycytidine)作用于BE1细胞可以使高甲基化的Axin基因去甲基化并上调Axin的转录。转染野生型Axin可以明显抑制BE1细胞和SPC-A-1细胞的增殖和侵袭(P<0.05),其中BE1细胞受到的抑制程度更为明显。结论 Axin基因高甲基化可能是其在肺癌中表达下调的重要原因,过表达Axin可以明显抑制Axin高甲基化肺癌细胞的增殖和侵袭能力。

Objective Axin is the key negative regnlator of Wnt pathway. This study is to explore the mechanism of the Axin downregulation in lung cancer and its effect on biological behavior of lung cancer cells. Methods Methylation specific PCR （MSP） was used to detect the methylated status of Axin gene promoter and first intron region in BE1 and SPC-A-1 cells. RT-PCR was used to explore the mRNA expression of Axin in the two cell lines. The wild type Axin plasmid was used to transfect the two cell lines, then MTT and transwe11 cell invasion assay were used to detect the change of proliferation and invasion. Results Hypermethylation was detected in the promoter and first intron region of Axin gene in BE1 cells, but not in SPC-A-1 cells. RT-PCR showed that the expression level of Axin mRNA was lower in BE1 cells than in SPC-A-1 cells （P 〈0.05）. 5-Aza-2＇-deoxycytidine treatment induced demethylation in BE1 cells and upregulated Axin mRNA expression. Transfection of wild type Axin plasmid could inhibit the proliferation and invasion in both cell lines, and much more effective in BE1 cells. Conclusion Hypermethylated Axin gene might be the main reason of its downregulation in lung cancer, overexpression of Axin gene could inhibit the proliferation and invasion more significantly in lung cancer cell line caused by hypermethylated Axin gene.