异硫氰酸苯己酯调控肝癌细胞株SMMC-7721组蛋白乙酰化及诱导细胞凋亡

目的 研究异硫氰酸苯己酯(PHI)对肝癌SMMC-7721细胞组蛋白乙酰化调控及凋亡的影响.方法 采用台盼蓝拒染直接计数法观察PHI对SMMC-7721细胞增殖的影响,采用原位末端标记(TUNEL)法检测PHI对SMMC-7721细胞凋亡的影响,采用Western blot法检测PHI对SMMC-7721细胞组蛋白乙酰化及凋亡相关蛋白表达的影响.结果 PHI可抑制SMMC-7721细胞的增殖,与0 μmol/L作用组比较,5、10、20、40和80 μmol/L的PHI对SMMC-7721细胞均有不同程度的增殖抑制作用.PHI可诱导SMMC-7721细胞产生凋亡,PHI作用于SMMC-7721细胞7 h后,10、20和40 μmol/LPHI组的细胞凋亡率分别为6.9%±2.4%、17.5%±4.2%和54.5%±5.4%,明显高于0 μmol/L PHI组(4.5%±2.3%,P＜0.05).PHI作用于SMMC-7721细胞3 h时,与0 μmol/L PHI组比较,10、20和40 μmol/L PHI组中Bcl-2、Procaspse-9和Procaspse-3的表达下降,caspase-9和caspase-3的表达上升,而Procaspase-8的表达未见明显变化;作用7 h时,这种变化趋势更加明显.PHI作用于SMMC-7721细胞3 h时,与0 μmol/L PHI组比较,10、20和40 μmol/L PHI组中组蛋白H3的乙酰化分别增加了1.87倍、2.43倍和3.67倍,组蛋白H4的乙酰化分别增加了1.29倍、1.45倍和2.25倍;作用7 h时,这种变化趋势更加明显.结论 PHI是一种组蛋白去乙酰化酶抑制剂,可调控组蛋白的乙酰化水平,影响其表观遗传学,并通过线粒体凋亡途径诱导细胞凋亡.

Modulation of histone acetylation and induction of apoptosis in SMMC-7721 cells by phenylhexyl isothiocyanate

Objective To investigate the effect of phenylhexyl isothiocyanate (PHI) on histone acetylation and apoptosis in hepatocellular carcinoma cell line (SMMC-7721) in vitro. Methods The viability of SMMC-7721 cells was determined by trypan blue exclusion. Apoptotic cells were assessed by TUNEL assay. The proteins of Bcl-2, Procaspase-9, Procaspase-8, Procaspase-3, caspase-9, caspase-3,histone acetylated H3 and H4 were detected by Western blot. Results Compared with the vehicle control,PHI at 5, 10, 20, 40 and 80 μ mol/L reduced the cell viability of SMMC-7721 cells in a concentrationdependent manner. PHI induced apoptosis in SMMC-7721 cells. An increased amount of apoptotic cells was detected after 7 hours exposure to PHI at 10, 20, and 40 μmol/L, 6.9% ±2.4%, 17.5% ±4.2% and 54.5% ±5.4%, respectively, while that of the vehicle control was4.5% ±2.3% (P ＜0.05). Along with the prolongation of time and increase of dose, the expressions of bcl-2, procaspase-9, procaspase-3 were decreased,that of caspase-9 and caspase-3 was increased. In contrast, alteration of procaspase-8 was not significant at those concentrations. PHI accumulated acetylated histone H3 and H4. After 3 hours exposure to PHI at 10, 20 and 40 μmol/L, the level of histone acetylated H3 was 1.87-, 2.43-, 3.67- fold increased and histone acetylated H4 was 1.29-, 1.45-, and 2.25- fold increased, compared with that of the vehicle control. The protein of histone acetylated H3 and H4 was significantly accumulated after 7 hours exposure.Conclusion PHI is a new histone deacetylation inhibitor. It may induce accumulation of histone acetylation H3 and H4, inhibit cell growth and induce apoptosis in SMMC-7721 cells via the mitochondrial pathway.