中文摘要：

目的观察亚毒性剂量雷帕霉素（RAPA）与低浓度奥沙利铂（L-OHP）联合用药对人结肠癌HCT116细胞的杀伤效果及凋亡的影响。方法应用MTr法检测L-OHP、RAPA单药或联合用药对细胞增殖的抑制作用；CalcuSyn2．0软件计算药物半数抑制浓度（IC50）及L-OHP和RAPA联合用药指数（cI）；流式细胞术和Western印迹法检测药物对细胞凋亡的影响。结果L-OHP和RAPA对HCT116细胞的增殖抑制作用均呈浓度依赖性，二者的48小时单药IC50分别为（8．35±0．78）μM（r=0．99）和（223．44±38．10）nM（r=0．94）。10nM（IC20）的RAPA与1μM（IC20）或2．5μM（IC30）的L-OHP联合应用后cI值分别为0．52和0．72。1μML—OHP与10nMRAPA联合用药组的细胞增殖抑制率为31％，约为同浓度单药组的2倍（P〈0．05）。10nMRAPA处理24小时的凋亡率与对照组无差别，联合用药的凋亡率高于L-OHP单药组。联合用药48小时后剪切型PARP（poly ADP-ribose polymerase）蛋白表达水平高于单药组。结论亚毒性剂量的RAPA和低浓度L-OHP组合协同抑制HCTl16细胞的增殖，其机制与增强诱导细胞凋亡相关。

英文摘要：

Objective To examine the anti - tumor efficacy and induction of apoptosis in combination therapy with low dose Rapamycin（RAPA） and Oxaliplatin（ L -OHP）in I-ICT116 colon cancer cell line in vitro. Methods The growth inhibitory effect was evaluated by MTr assay in single agent or combination therapy. ICs0 values were determined by using CalcuSyn 2.0 software. To determine interaction of the drugs ,combination index （CI） were calculated by the method of Chou and Talalay. Apoptosis was investigated by flow cytometry and west- ern blotting. Results Both RAPA and L - OHP inhibited cell proliferation in a does - dependent manner and the ICso values were （ 8.35 ± 0.78 ）μM （ r = 0.99 ） and （ 223.44 ± 38.10 ）nM （ r = 0.94 ）, respectively. The CI values were 0.52 and 0.72 when a combination of 10 nM RAPA（ IC20 ） with 1 μM（ IC20 ） or 2.5μM（ IC30 ） L - OHP were used. The cytotoxicity of 10 nM RAPA and 1μM L - OHP combination reached to 31% ,which were nearly 2 folds of using L - OHP alone. The apoptotic rate of combination therapy after 24 hours treatment was higher than that of L - OHP alone,although RAPA at a subtoxic concentration of 10 nm did not induce apoptosis. The cleaved - PARP protein expression level was the highest after 48 hours combination treatment. Conclusion RAPA at a subtoxic concentration in combination with low dose L - OHP synergistically inhibited HCT116 cancer cell growth in vitro. The mechanism was in relation to enhanced apoptosis.