美伐他汀诱导人非小细胞肺癌细胞凋亡及其分子机制的研究

Mevastatin induces apoptosis of human non small cell lung carcinoma and its molecular mechanism

目的:研究美伐他汀对非小细胞肺癌细胞(nod-small-cell lung cancer,NSCLC)诱导凋亡及其分子机制。方法:应用MTT法检测美伐他汀对A549、NCI-H520细胞株的体外增殖作用,应用流式细胞仪,透射电镜,研究美伐他汀对A549、NCI-H520细胞株的细胞周期阻滞和诱导调亡的作用,应用流式细胞术和RT-PCR检测P21蛋白、P21 mRNA、XIAP mRNA的表达,以研究细胞周期阻滞和诱导调亡的机制。结果:MTT试验表明:美伐他汀对A549、NCI-H520增殖有明显的抑制作用,且表现为剂量依赖性和时间依赖性;流式细胞学显示:美伐他汀诱导A549、NCI-H520细胞G0／G1期阻滞;Annexin V结果证实美伐他汀可诱导A549、NCI-H520细胞凋亡,而且凋亡率随剂量的增加而增加。美伐他汀对A549、NCI-H520细胞P21 mRNA及P21总蛋白的表达无影响,但可使P21细胞膜蛋白的表达下降。美伐他汀作用后XIAP mRNA的表达下降,加入外源性甲羟戊酸可完全逆转美伐他汀的上述作用。结论:美伐他汀通过抑制甲羟戊酸合成途径诱导NSCLC细胞G0／G1阻滞,抑制增殖,诱导细胞凋亡,其机制可能与抑制P21蛋白异戊二烯化和下调XIAP mRNA的表达有关。

Objective. To investigate the effect of mevastatin on apoptosis of human non-small-cell lung carcinoma （NSCLC） and explore the corresponding mechanism. Methods：The inhibitory effect of mevastatin on proliferation of A549 and NCI-H520 cell lines in vitro was detected by MTT assay. The cell cycle arrest and apoptosis were observed by flow cytometry analysis and transmission electron microscopy. The expression of p21 protein was determined by flow cytometry. The mRNA expression of P21 and X-chromosome-linked inhibitor of apoptosis protein （XIAP） was measured with reverse transcription-polymerase chain reaction. Results：Mevastatin significantly inhibited proliferation of A549 and NCI-H520 cells in a time- and concentration-dependent manners. Flow cytometry analysis showed that mevastatin induced G0/G1 arrest of A549 and NCI-H520 cells. Annexin V staining demonstrated that mevastatin induced apoptosis of A549 and NCI-H520 cells in a concentration-dependent manner. Mevastatin had no effects on expression of p21 mRNA and total protein but decreased p21 protein expression on cellular membrane. Mevastatin reduced the expression of XIAP mRNA in NSCLC cell lines. These effects of mevastatin could be reversed by addition of 100 μmol/L exogenous mevalonate. Conclusion：Mevastatin causes G0/G1 arrest, inhibits proliferation, and induces apoptosis of NSCLC cells in vitro by inhibition of mevalonate synthesis. The mechanism involves blockade of isoprenylation of p21 protein and down-regulation of XIAP mRNA expression.