PI3K抑制剂对食管癌Eca-109细胞株放射增敏作用及机制

Radiosensitization of phosphatidylinositol 3-kinase inhibitor on esophageal cancer cell line Eca-109 and its mechanism

目的:研究PI3K抑制剂对食管癌细胞株Eca-109放射增敏作用及机制.方法:以食管癌细胞株Eca-109为实验对象,MTT法观察PI3K抑制剂LY294002对Eca-109细胞增殖抑制;克隆形成实验分析细胞放射敏感性;RT-PCR检测DNA双链断裂修复基因DNA-PKcs mRNA表达;流式细胞技术检测细胞周期.结果:PI3K抑制剂LY294002对Eca-109细胞有生长抑制作用,且呈剂量依赖性,在较低浓度(10μmol/L)时即可降低Eca-109细胞的克隆形成率,其放射增敏比为1.58.药物LY294002组DNA-PKcs mRNA表达受抑,但与对照组比较差异无统计学意义;照射组表达较对照组明显升高(P<0.05);药物LY294002+照射组的表达较照射组下降(P<0.05).药物LY294002组G2期细胞比例与对照组比较差异无统计学意义,照射组较对照组升高(P<0.01),药物LY294002+照射组G2期细胞比例较照射组下降(P<0.05).结论:PI3K抑制剂LY294002对Eca-109细胞有放射增敏作用,其机制可能与抑制肿瘤细胞DNA双链断裂修复基因DNA-PKcs及减少G2期细胞阻滞有关.

AIM：To investigate the radiosensitization effect and possible mechanism of P13K inhibitor-LY294002 on esophageal cancer cell line Eca-109. METHODS： MTT assay was used to test the inilibitory effect of LY294002 on tumor cell proliferation and clonogenic assay was performed to determine the radiosensitization effect of LY294002 on Eca-109 cell line. RT-PCR was used to detect the expression of DNA double-strand break repair gene-DNA-PKcs mRNA and cell cycle was detected by flow cytometry. RESULTS： PI3K inhibitor LY294002 inhibited Eca-109 cell line proliferation in a dose-dependent manner. A low-cytotoxic concentration of LY294002 at 10 μmol/L significantly reduced the cloning efficiency of Eea-109 cell and the radiosensitization enhancement ratio was 1. 58. Expression of DNA-PKcs mRNA in the drug group was inhibited compared with that in the control group, with no statistically significance. Expression of DNA-PKcs mRNA in the radiation group was higher than that in the control group（ P 〈 0.05 ）, but it was significantly reduced in the LY294002 ＋ radiation group compared with that in the radiation group（P 〈0.05 ）. No statistical difference was found in the G2 phase cell proportion between drug group and control group. G2 phase cell proportion in the radiation group was significantly higher than that in control group （ P 〈 0.01 ）, but it was significantly reduced in the LY294002 ＋ radiation group compared with that in the radiation group （P 〈 0.05 ）. CONCLUSION： PI3K inhibitor LY294002 enhances the radiosensitivity of human esophageal cancer cell line Eca-109 and this effect is possibly associated with the expression inhibition of DNA-PKcs mRNA and abrogation of radiation-induced G2 phase arrest.