组蛋白去乙酰化酶抑制剂对乏氧宫颈癌HeLa细胞放射敏感度的影响

Effect of histone deacetylase inhibitor trichostatin A on radiosensitivity of human cervical cancer cell line HeLa under hypoxia condition

目的:观察组蛋白去乙酰化酶抑制剂曲古霉素A(trichostatin A,TSA)对乏氧状态下人宫颈癌HeLa细胞放射敏感度的影响。方法:应用不同浓度TSA作用经乏氧预处理的人宫颈癌HeLa细胞12、24、48和72 h,MTT法检测HeLa细胞的增殖率,计算半数抑制浓度(half inhibitory concentration,IC50)和IC10值;克隆形成实验检测TSA(IC10)作用24 h对乏氧HeLa细胞的放射增敏效应;免疫细胞化学法检测TSA(IC10)对HeLa细胞中乏氧诱导因子-1α(hypoxia-inducible factor-1 alpha,HIF-1α)和血管内皮生长因子(vascular endothelial growth factor,VEGF)蛋白表达的影响。结果:TSA对乏氧宫颈癌HeLa细胞的增殖率有明显的抑制作用,且随着TSA浓度的增加和作用时间的延长,其抑制作用逐渐增强。与乏氧照射组比较,TSA(IC10)作用乏氧HeLa细胞24 h,可增加细胞的放射敏感度(P<0.05)。乏氧HeLa细胞中HIF-1α和VEGF蛋白的表达明显高于常氧组细胞;与乏氧组比较,TSA(IC10)作用乏氧HeLa细胞24 h后,细胞中HIF-1α和VEGF蛋白表达下调。结论:TSA可能通过抑制乏氧HeLa细胞中HIF-1α和VEGF蛋白的表达而发挥放射增敏效应。

Objective：To investigate the effects of histone deacetylase inhibitor trichostatin A（TSA） on radiosensitivity of human cervical cancer cell line HeLa under hypoxia condition.Methods：Under hypoxia condition,the HeLa cells were treated with different concentrations of TSA for 12,24,48 and 72 h,respectively.The survival rate of HeLa cells was detected by MTT assay.The half inhibitory concentration（IC50） and IC10 values for TSA were calculated.The radiosensitivity in HeLa cells treated with TSA（IC10） for 24 h under hypoxia condition was detected by colony formation assay.The expressions of hypoxia-inducible factor-1 alpha（HIF-1α） and vascular endothelial growth factor（VEGF） proteins were measured by immunocytochemistry.Results：The survival rate of HeLa cells induced by TSA and hypoxia was decreased in a concentration and time-dependent manner.The radiosensitivity of HeLa cells under hypoxia condition was increased by treatment with TSA（IC10） for 24 h（P0.05）.The expressions of HIF-1α and VEGF proteins were higher in HeLa cells exposed to hypoxia than that in HeLa cells exposed to normoxia.The expressions of HIF-1α and VEGF proteins in HeLa cells under hypoxia condition were decreased by treatment with TSA（IC10） for 24 h.Conclusion：TSA can significantly enhance the radiosentivity of HeLa cells under hypoxia condition.This effect may be related with the down-regulation of HIF-1α and VEGF protein expression.