摘要
目的:观察三氧化二砷(As2O3)在低氧条件下对食管癌Eca109细胞增殖、细胞周期及凋亡的影响,探讨其发挥放射增敏作用的可能机制。方法:Co Cl2处理模拟肿瘤细胞模拟低氧微环境,MTT法分别检测常氧和低氧条件下不同浓度As2O3及不同剂量放射线对食管癌Eca109细胞增殖的抑制作用,流式细胞术检测低氧下As2O3、放射线单独及两者联合对细胞周期及凋亡的影响,Western blotting检测经As2O3、放射线单独及两者联合作用后Eca109细胞中HIF-1α、p27蛋白的表达情况。结果:在常氧和低氧两种条件下,As2O3均呈时间和剂量依赖方式抑制Eca109细胞增殖,相同时间和相同剂量条件下,其抑制水平相当(P>0.05);而低氧下放射线对Eca109细胞增殖的抑制作用较常氧下明显减弱(P<0.05)。低氧下Eca109细胞周期出现G0/G1期阻滞、G2/M期细胞比例明显减少(P<0.05),As2O3在低氧条件下可诱导G2/M期阻滞、G0/G1期细胞比例减少。As2O3与放射线联合作用时,Eca109细胞的凋亡率大于两者单独作用之和。低氧条件下,Eca109细胞HIF-1α、p27蛋白表达均明显增强,As2O3可逆转HIF-1α、p27表达水平的升高。结论:低氧条件下,As2O3对食管癌Eca109细胞有放射增敏作用,其机制可能与下调HIF-1α进而降低p27表达水平、解除G0/G1期细胞周期阻滞和促进细胞凋亡有关。
Objective: To investigate the effect of arsenic trioxide( As2O3) on proliferation,cycle progression,apoptosis and radio-sensitivity of esophageal carcinoma cells under hypoxia. Methods: Human esophageal carcinoma Eca109 cells were treated with different concentrations of As2O3 or doses of radiation under a hypoxic condition mimicked cobalt chloride( Co Cl2). At different time points after treatment,cell viability was determined by MTT assay,cell cycle progression and apoptosis by flow cytometry( FCM),and expression of HIF-1α and p27 at the protein level by Western blotting.Results: In time- and dose-dependent manners,As2O3 inhibited Eca109 cell proliferation similarly under both normoxic and hypoxic conditions( P > 0. 05). However,radiation-mediated inhibition of Eca109 cell proliferation was significantly less strong under hypoxia than under normoxia( P < 0. 05). Compared with normoxia,hypoxia increased cell cycle arrest at the G0/ G1 phase and decreased the proportion of cells at the G2/ M phase( P < 0. 05). As2O3 induced cell cycle arrest at the G2/ M phase and reduced the proportion of cells at the G0/ G1 phase under hypoxia. The combination of As2O3 and irradiation resulted in more significant apoptosis in Eca109 cells as compared with the use of As2O3 and irradiation each alone( P < 0. 05). Under hypoxia,HIF-1α and p27 protein contents were significantly increased as compared with normoxia( P < 0. 05),but the increase was significantly attenuated by As2O3( P < 0. 05). Conclusions: Under hypoxia,As2O3 may increase the sensitivity esophageal carcinoma cells to radiation,possibly through down-regulating the expression of HIF-1α and its down-stream target p27,thus releasing G0/ G1 phase arrest and inducing G2/ M phase arrest.
出处
《中国肿瘤生物治疗杂志》
CAS
CSCD
北大核心
2015年第1期41-46,共6页
Chinese Journal of Cancer Biotherapy
基金
高等院校博士学科点专项科研基金资助(No.20091323110011)~~
