古抑菌素A诱导人肝癌HepG2细胞凋亡及对脆性组氨酸三联体蛋白和凋亡相关蛋白表达的影响

目的:研究组蛋白去乙酰化转移酶抑制剂古抑菌素A(TSA)对人肝癌HepG2细胞的抑制作用以及对脆性组氨酸三联体(FHIT)蛋白和凋亡相关蛋白caspase-3、bax、bcl-2表达的影响,初步探讨其诱导凋亡的机制。方法:以不同浓度TSA(125、250、500、1000、2000nmol·L-1)处理体外培养的人肝癌HepG2细胞,孵育24、48h后采用MTT法、以吸光度值和抑制率为指标检测细胞的生长抑制情况;分别用原位末端脱氧核苷转换酶标记(TUNEL)法和免疫细胞化学法检测TSA(250、1000nmol·L-1)作用后细胞凋亡率和细胞中FHIT、caspase-3、bax、bcl-2的蛋白表达;同时设立溶剂为对照组。结果:与对照组比较,不同浓度TSA作用后吸光度值降低,抑制率升高,并呈明显的剂量依赖和时间依赖关系;TUNEL阳性细胞百分率升高(P<0.01)、细胞中FHIT、cas-pase-3、bax蛋白表达增强(P<0.05),bcl-2的变化不明显(P>0.05)。结论:TSA可能通过上调FHIT、caspase-3、bax蛋白的表达而诱导肝癌HepG2细胞凋亡。

Effect of Trichostatin A on Apoptosis of Human Hepatoma Cell Line HepG2 and Expression of FHIT and Apoptosis-related Proteins

OBJECTIVE： To investigate the effect of trichostatin A （TSA）,a specific inhibitor of histone acetyltransferase,on apoptosis of human hepotoma cell line HepG2,the expression of fragile histidine triad （FHIT） and apoptosis-related proteins in order to study apoptosis mechanisms.METHODS： Human hepatoma cell lines HepG2 were cultured and treated with different concentrations of TSA（125,250,500,1 000,2 000 nmol·L-1） for 24 and 48 hours.Human hepatoma cell lines HepG2 survival and apoptosis were determined by MTT assay with absorbance vale and inhibitory rate as index.Apoptotic percentage of HepG2 treated with 250 and 1 000 nmol·L-1 TSA were determined using TUNEL assay.The expressions of FHIT and caspase-3,bax,bcl-2 were analyzed by immunocytochemistry with solvent as control.RESULTS： As compared with control group,absorbance vale of human hepatoma cell lines HepG2 were decreased after treated with different concentration of TSA in dose-dependent and time-dependent manners.Positive cell rate in TUNEL was increased （P0.01）,the protein expressions of FHIT and caspase-3,bax were up-regulated （P0.05） but the protein expression of bcl-2 had no obvious change （P0.05）.CONCLUSION： TSA may inhibit proliferation and promote apoptosis of hepatoma HepG2 cell by up-regulating the protein expression of FHIT,caspase-3 and bax.