乙醇降低人乳腺癌MCF-7细胞放射敏感性的研究

目的 研究乙醇对人乳腺癌MCF-7细胞放射敏感性的影响及相关机制.方法 将人乳腺癌MCF-7细胞分为4组,对照组(不做任何处理)、乙醇组(乙醇处理)、单纯照射组(6 GyX射线处理)和联合组(乙醇与X射线联合作用).克隆形成法检测50或100 mmol/L乙醇对MCF-7细胞放射敏感性的影响；流式细胞术检测细胞周期变化；Annexin V-FITC法检测细胞凋亡.结果 50和100 mmol/L乙醇处理MCF-7细胞50 h,对生长无明显影响(t--0.82和1.15,P＞0.05)；乙醇预处理2h,可明显增加X射线照射后MCF-7细胞克隆形成的能力(t=4.15和10.28,P＜0.05).相比于单纯照射组,乙醇降低了X射线照射诱导的细胞G2/M期阻滞(t=7.18,P＜0.05),以及sub-G1 峰的比例(t =5.39,P＜0.05).而且,Annexin V-FITC检测结果示,乙醇联合X射线照射的细胞晚期和早期凋亡减少(t=4.86和7.59,P＜0.05).结论 乙醇可以增加MCF-7细胞的辐射抗性,其机制可能与降低辐射诱导的细胞G2/M期阻滞及早、晚期凋亡的发生相关.

Ethanol decreases radiosensitivity of human breast cancer MCF-7 cells

Objective To investigate the effect of ethanol on radiosensitivity of human breast cancer MCF-7 cells. Methods Human breast cancer MCF-7 cells were divided into four groups including control group, ethanol treatment group, X-ray exposed group, and ethanol combined with X-ray group. Clonogenic assay was used to determine cell survival. Flow cytometry was employed to analyze cell cycle progression. Annexin V-FITC kit was used to determine cell apoptosis induction. Results Ethanol(50 and 100 mmol/L,50 h)had no influence on MCF-7 cell growth(t=0.82,1.15,P>0.05). The radiosensitivity of MCF-7 cells was reduced when the cells were pretreated with 50 mmol/L ethanol (t=4.15,P<0.05) and 100 mmol/L ethanol(t=10.28,P<0.05)for 2 h. Compared with irradiation with X-ray alone, ethanol treatment decreased G₂/M phase arrest(t=7.18,P<0.05) and sub-G₁ population(an indicator of apoptosis induction)(t=5.39,P<0.05). A decrease of advanced and early apoptosis in the cells pretreated with ethanol was also confirmed by Annexin V-FITC apoptosis assay(t=4.86,7.59,P<0.05). Conclusions Ethanol causes radioresistance in human breast cancer MCF-7 cells, where the decreases of radiation-induced G₂/M phase arrest and apoptosis may be involved.