BH3-only在奥沙利铂诱导结肠癌细胞凋亡中的作用

目的研究BH3-only基因表达在奥沙利铂诱导人结肠癌细胞株凋亡中的作用及其机制。方法采用不同浓度（0．3、0．6、1．25、2，5、5、10和20mg／L）奥沙利铂处理人结肠癌细胞株SW480及HT29，应用MTT检测细胞生长抑制情况；流式细胞仪检测凋亡情况；荧光定量PCR检测BH3-only基Bim和PUMA表达。结果不同浓度奥沙利铂分别作用于结肠癌细胞SW480后，出现不同程度的细胞生长抑制作用，呈剂量依赖性。5mg／L和10mg／L浓度的奥沙利铂作用于SW480细胞24h后，细胞凋亡率分别为（4．87±0．55）％和（12．10±1．04）％，作用48h后分别为（11．47±0．85）％和（30．07±2．01）％，作用72h后分别为（28．99±2．12）％和（38．32±3．15）％，均显著高于相应时间点对照组细胞的凋亡率（0．30±0．10）％、（0．40±0．10）％和（0．50±0．20）％，均P〈0．01]。同时Bim和PUMAmRNA表达水平也显著高于对照组（P〈0．05）。而同样处理的HT29细胞其生长抑制率、细胞凋亡率及Bim和PUMAmRNA表达水平与对照组比较差异无统计学意义（P〉0．05）。结论奥沙利铂具有抑制结肠癌细胞株SW480生长并诱导其凋亡的作用，其机制可能与促凋亡相关基因BH3-only（Bim和PUMA）表达增强有关。

Role of BH3-only gene in the oxaliplatin-induced apoptosis of colon cancer cells

Objective To study the role of BH3-only gene in oxaliplatin-induced apoptosis of human colon cancer cell line, and to explore the associated mechanisms. Methods Two strains of human colon cancer cell line SW480 and HT29 were selected, and treated respectively with different concentrations of oxaliplatin （0.3, 0.6, 1.25, 2.5, 5, 10 and 20 mg/L）. Cell growth and inhibition were detected by MTT method. Apoptosis was measured by flow cytometry. Bim and PUMA expressions were examined by fluorescence quantitative PCR. Results After treatment of different oxaliplatin concentrations in human colon carcinoma cells SW480 line, the cell growth was inhibited in a dosedependent manner, while Bim and PUMA expressions were significantly up-regulated. While HT29 cell lines received the same treatment, no obvious inhibition of cell growth and up-regulation of Bim and PUMA expression were found. When SW480 cells were exposed to 5 mg/L and 10 mg/L of oxaliplatin for 24 h, the early apoptotic rates were （4.87±0.55）% and （12.10±1.04）%; for 48 h, the early apoptotic rates were （11.47±0.85）% and （30.07±2.01）%; for 72 h, the early apoptotic rates were （28.99±2.12）% and （38.32±3.15）% respectively, whieh were all significantly higher than those in control group （0.30±0.10）%, （0.40±0.10）% and （0.50±0.20）%, all P〈0.01 ]. In HT29 cells, the differenees of apoptotic rates between oxaliplatin treatment group and control group were not statistieally significant （all P〉0.05）. Conclusions Oxaliplatin can inhibit colon cancer cell line SW480 growth and induce apoptosis. Induction of apoptosis of colon cancer cells by oxaliplatin may be associated with the up-regulation of BH3-only proteins, Bim and PUMA.