目的 探讨组蛋白去乙酰化3(HDAC3)抑制剂Psammaplin A对离体结肠癌细胞增殖、凋亡的影响及机制.方法 取处于对数生长期结肠癌SW480细胞,随机分为Psammaplin组与对照组,Psammaplin组给予不同浓度(0.5、5、50、500、5 000 μg/mL)Psammaplin A干扰48 h,对照组不给予任何干预.采用Western blotting法检测HDAC3及DNMT3a蛋白表达:MTT法检测不同细胞培养时间(24、48、72、96 h)、不同浓度梯度Psammaplin A对SW480细胞增殖的影响.流式细胞术检测Psammaplin A对SW480细胞周期及凋亡的影响.结果 Psammaplin组0.5、5、50、500、5 000μg/mL的Psammaplin A干扰SW480细胞48 h后,HDAC3蛋白相对表达量分别为23.28±8.91、21.72 ±9.18、18.63±7.26、14.17±5.64、10.58±7.22,对照组HDAC3蛋白相对表达量为24.84±7.65,与对照组比较,Psammaplin组在500及5 000 μg/mL时差异有统计学意义(P均＜0.05).Psammaplin组0.5、5、50、500、5 000 μg/mL的Psammaplin A干扰SW480细胞48 h后,DNMT3a蛋白相对表达量分别为18.36±8.43、17.51±6.29、16.12 ±6.54、11.27±5.31、10.54 ±-4.26,对照组为20.15±6.31,与对照组比较,Psammaplin组在500及5 000μg/mL时差异有统计学意义(P均＜0.05).50 μg/mL的Psammaplin A干预SW480细胞培养24、48、72及96 h后,Psammaplin组细胞存活率为时间依赖性下降,与对照组比较,在48、72及96 h时差异均有统计学意义(P均＜0.05);Psammaplin组0.5、5、50、500、5 000 μg/mL的Psammaplin A作用48 h后,与对照组比较,SW480细胞存活率呈剂量依赖性下降,在50、500、5 000 μg/mL时差异有统计学意义(P均＜0.05).Psammaplin组与对照组G1期细胞所占比例分别为(69.27±0.93)％、(81.25±0.89)％,G2期细胞所占比例分别为(4.72±1.83)％、(9.62±1.34)％,S期细胞所占比例分别为(27.61±1.65)％、(10.43 ±0.97)％,两组各期细胞所占比例比较,P均＜0.05.Psammaplin组与对照组细胞凋亡率分别为56.98％、31.67％,两组比较,P＜0.01.结论 Psammaplin A可通过抑制HDAC3及DNMT3a表达降低结肠癌细胞存活率及增殖活性,诱导凋亡.%Objective To observe the effect of histone deacetylase 3 (HDAC3) inhibitor Psammaplin A on the proliferation and apoptosis of colon cancer cells in vitro.Methods Colon cancer SW480 cells in logarithmic phase were randomly divided into Psammaplin group and control group.Different concentrations of Psammaplin A (0.5,5,50,500 and 5 000 μg/mL) were given and interfered for 48 h to cells in the Psammaplin A group,and no interference was given to cells in the control group.HDAC3 and DNMT3a protein expression was detected by Western blotting.MTT assay was used to detect the proliferation of SW480 affected by Psammaplin A in different concentrations and culture time (24,48,72,96 h).Flow cytometer was used to detect the cell cycle and apoptosis affected by Psammaplin A.Results HDAC3 relative protein expression in the Psammaplin group which was interfered by 0.5,5,50,500 and 5 000 μg/mL Psammaplin A for 48 h was 23.28 ± 8.91,21.72 ± 9.18,18.63 ± 7.26,14.17 ± 5.64,10.58 ± 7.22,and 24.84 ± 7.65 in the control group.Compared with control group,the differences were significant in the Psammaplin at 500 and 5 000 μg/mL (all P ＜0.05).DNMT3a relative protein expression in the Psammaplin group which was interfered by 0.5,5,50,500 and 5 000 μg/mL Psammaplin A for 48 h was 8.36 ± 8.43,17.51 ± 6.29,16.12 ± 6.54,1 1.27 ± 5.31 and 10.54 ± 4.26,and 20.15 ± 6.31 in the control group.Compared with contml group,the differences were significant in the Psammaplin at 500 and 5 000 μg/mL (all P ＜ 0.05).After SW480 cells were interfered with 50 μg/mL Psammaplin A and cultured for 24,48,72 and 96 h,the survival rate in the Psammaplin group was decreased in a time-dependent manner.Compared with the control group,the difference was significant at 48,72 and 96 h (all P ＜ 0.05).The survival rate in the Psammaplin group treated with 0.5,5,50,500 and 5 000 μg/mL Psammaplin A for 48 h was decreased in a dose-dependent manner,and the different was significant at 50,500 and 5 000 μg/mL as compared with survival rate in the control group (all P ＜0.05).The percentages of cells in G1 phase of the Psammaplin group and control group were 69.27％ ± 0.93％ and 81.25％ ±0.89％,respectively,and those in the G2 phase were 4.72％ ± 1.83％ and 9.62％ ± 1.34％,in S phase were 27.61％ ± 1.65％ and 10.43％ ± 0.97％,and the differences were significant (all P ＜ 0.05).The apoptosis rate in the Psammaplin group and control group was 56.98％ and 31.67％,respectively,and the difference was significant (P ＜0.01).Conclusion Psammaplin A decreases the survival rate and proliferation of colon cancer cells by inhibiting the expression of HDAC3 and DNMT3a,and induces apoptosis.
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