Periostin基因过表达对顺铂和5-氟尿嘧啶诱导人胃癌细胞凋亡的影响

Effect of Periostin Gene Overexpression on Cisplatin- and 5-Fluorouracil-induced Apoptosis in Human Gastric Cancer Cells

背景:肿瘤细胞耐药性的产生是肿瘤化疗失败的主要原因之一。Periostin是一种基质特异性细胞黏附分子。既往研究发现,periostin除参与胃癌细胞的生长、侵袭、转移外,还能降低其对化疗药物的敏感性。目的:明确periostin基因过表达对顺铂和5-氟尿嘧啶(5-Fu)诱导人胃癌细胞凋亡的影响及其可能机制。方法:将表达人periostin全长序列的重组质粒稳定转染人胃癌细胞株SGC7901,同时设置空载体稳定转染组和未转染对照组,加入不同浓度顺铂或5-Fu处理24 h,以流式细胞术检测细胞凋亡。以蛋白质印迹法检测经5μmol/L顺铂或10μmol/L 5-Fu处理的SGC7901细胞的凋亡相关蛋白表达。结果:顺铂和5-Fu均能剂量依赖性地诱导SGC7901细胞凋亡,促进细胞色素c由线粒体释放至胞质,同时caspase-3激活,caspase-3底物PARP剪切增强。periostin稳定转染组SGC7901细胞对顺铂和5-Fu诱导的细胞凋亡具有显著抗性,细胞凋亡率显著低于经相同剂量化疗药物处理的空载体稳定转染组(P<0.05),胞质细胞色素c、cleaved caspase-3、cleaved PARP蛋白表达亦明显下调。结论:过表达periostin基因可增强SGC7901细胞对顺铂和5-Fu诱导的细胞凋亡的抵抗能力,其抗凋亡活性与抑制线粒体依赖性凋亡途径有关。

Background：Acquisition of drug resistance is one of the main causes for failure of chemotherapy in the treatment of cancer. Previous studies indicated that periostin, a matrix-specific cell adhesion molecule, was involved not only in the growth, invasion and metastasis of gastric cancer cells, but also in their resistance to chemotherapy. Aims ： To investigate the effect of periostin gene overexpression on cisplatin- and 5-fluorouracil （5-Fu）-induced apoptosis in human gastric cancer cells and the possible mechanism. Methods： Recombinant plasmid expressing full-length human periostin was transfected into human gastric cancer cell line SGC7901 to establish a stable transfection cell line. Cells transfected with empty plasmid and non-transfected cells were served as controls. Ceils were exposed to cisplatin or 5-Fu at different concentrations for 24 hours. Cell apoptosis was assessed by flow cytometry, and the expressions of apoptosis-related proteins in cells exposed to 5μmol/L cisplatin or 10μmol/L 5-Fu were determined by Western blotting. Results： Both cisplatin and 5-Fu caused a dose-dependent induction of apoptosis in SGC7901 ceils, meanwhile enhanced the mitochondrial cytochrome c release and cleavage of caspase-3 and PARP （ the substrate of caspase-3 ）. SGC7901 ceils transfected with the recombinant plasmid demonstrated a resistance to cisplatin- and 5-Fu-induced apoptosis, the apoptosis rate was significantly lower than cells transfected with empty plasmid exposure to the same cytotoxic agent at same concentration （ P 〈 0.05 ）. Periostin gene overexpression also markedly abrogated the cisplatin- and 5-Fu-induced up-regulation of cytosol cytochrome c, cleaved caspase-3 and cleaved PARP expression. Conclusions： Overexpression of periostin gene in SGC7901 cells confers a resistance to cisplatin- and 5-Fu-induced apoptosis, and this anti-apoptotic effect is related to the inhibition of mitochondria-dependent apoptotic pathway.