白桦脂酸对Jurkat白血病细胞增殖和凋亡的影响

目的 观察白桦脂酸对人T淋巴细胞白血病Jurkat细胞株细胞增殖、凋亡和细胞周期的影响,并探讨其分子机制.方法 以不同浓度的白桦脂酸处理Jurkat细胞,采用二苯基溴化四氮唑蓝(MTY)法检测细胞的增殖活性,Hoechst 33258染色和Annexin-V/PI双标法检测细胞凋亡,流式细胞仪检测细胞周期分布,逆转录聚合酶链反应(RT-PCR)法检测Jurkat细胞中cyclin D3和bcl-xlmRNA含量的变化,Western blot法检测cyclin D3和bcl-xl蛋白的表达.结果 白桦脂酸对Jurkat细胞有明显的增殖抑制作用,并呈时间和浓度依赖性.白桦脂酸可诱导Jurkat细胞凋亡,Hoechst 33258染色可见典型的凋亡小体;Annxin-V/PI双标法显示,20、60和100 μmol/L白桦脂酸作用于Jurkat细胞24 h时,细胞的早期凋亡率分别为8.7%±0.3%、28.0%±1.3%和33.6%±2.0%.白桦脂酸可使Jurkat细胞的细胞周期阻滞于G0/G1期.白桦脂酸可使Jurkat细胞中凋亡相关基因cyclin D3和bcl-xl mRNA及蛋白的含量均明显减少,并呈浓度依赖性.结论 白桦脂酸可抑制Jurkat细胞增殖并诱导其凋亡,可使细胞阻滞于G0/G1期;其可能通过下调cyclin D3和bcl-xl mRNA及蛋白的表达而发挥抗肿瘤作用.

Effect of bctnlinic acid on proliferation and apoptosis in Jurkat cells and its mechanism

Objective To investigate the anticancer effects of betulinic acid(BA)on Jurkat cells in vitro and its molecular mechanism.Methods The effects of betulinic acid on the growth of Jurkat cells were studied by 3-(4,5-dimethyl-2-thiazolyl)-2,5diphenyl-2H-tetrazolium(MTT)assay.Apoptosis was assessed by Hoechst33258 staining and annexin-V/PI double-labeled cytometry.The effect of betulinic acid on the cell cycle of Jurkat cells was studied by pmpidium iodide staining.RT-PCR and Western blot were used to analyze the changes of cyclin D3.bel-xl mRNA and protein levels in Jurkat cells after treatment with betulinic acid.Results The proliferation of Jurkat cells was decreased in betulinic acid-treated group at a 24 h IC50 valne of 70.0 μmol/L.The effect of betulinic acid to induce apoptosis in Jurkat cells was in a time-and dose-dependent manner.Jurkat cells treated with betulinic acid showed an increase of G0/G1 phase and decrease of S phase.The Jurkat cells treated with 0,20,60,100μmol/L betulinic acid for 24 h.showed an increased G0/G1 phase from 31.0%to 58.8%,whereas decreased S phase from 61.5%to 35.8%,respectively.PBMC was less sensitive to the cytotoxic effect of betulinic acid than Jurkat cells.The expression of cyclin D3.bcl-xl mRNA and protein were decreased sharply in Jurkat cells treated with betulinic acid.Conclusion Betulinic acid call inhibit the proliferation of Jurkat cells by regulating the cell cycle that arrests cells at G0/G1 phase and induces apoptosis in Jurkat cells.The antitttmor effects of betulinic acid may be related to down-regulation of the expression of cyclin D3 and bcl-xl.