As2O3诱导NB4、HL-60细胞凋亡的机制研究

目的探讨三氧化二砷(As2O3)在体外抑制急性早幼粒白血病(acute promyelocyticleukemia, APL)细胞NB4、HL-60细胞增殖,诱导细胞凋亡的分子机制。方法 通过WST-8法检测上述两个细胞株的增殖抑制曲线;用AnnexinV/PI流式细胞术检测细胞的凋亡;用Real time PCR检测凋亡相关基因Caspase-3、Caspase-8、Caspase-9、Bcl-2、Bax、p53、C-myc、Survivin在As2O3处理前后的表达变化,同时用Westernblot检测凋亡相关蛋白Caspase-3、Caspase-8、Caspase-9、Bcl-2、Bax、P53在As2O3处理前后的表达变化。结果 As2O3能够显著抑制两种细胞增殖, Westernblot检测及Realtime PCR结果显示,As2O3处理引起了两种细胞中Bax、Caspase-3、Caspase-8 、Caspase-9基因表达水平增加,且蛋白表达水平上都出现了活性形式的Caspases。NB4细胞中Survivin、C-myc、Bcl-2的基因表达水平都显著降低,突变型p53蛋白在细胞内的量同样显著下降；HL-60细胞的C-myc表达水平显著降低,但Survivin、Bcl-2表达水平无明显变化。结论 As2O3能在药物临床浓度范围内有效抑制急性早幼粒白血病细胞HL-60、NB4的细胞增殖, 但方式不同；1.5μmol/L浓度的As2O3对NB4细胞生长的抑制体现在诱导细胞分化并诱导细胞凋亡,对HL-60细胞生长的抑制只体现在诱导细胞分化。HL-60细胞中高表达的Survivin、Bcl-2抑制了细胞的凋亡。NB4、HL-60细胞株中P53基因的细胞遗传学变异的不同可能是As2O3对这两种细胞增殖抑制机制差异的主要原因之一。
Objective To investigate the mechanism of arsenic trioxide (As2O3) -induced apoptosis in acute promyelocytic leukemia(APL)NB4 and HL60 cells.Methods NB4 and HL60 cells were treated with As2O3 at different concentrations. Cell proliferation was determined by WST-8 assay. The apoptosis rate was detected by flow cytometry with annexinV-FITC/PI double staining.The mRNA expression of apoptosis-related genes caspase-3, Caspase-8, Caspase-9, Bcl-2,Bax, the proto-oncogene C-myc, survivin, p53 and granulocytes differentiation antigen CD11b was detected by RT-PCR. The expression of apoptosis-related proteins caspase-3, Caspase-8, Caspase-9, Bcl-2,Bax was determined by Western blotting. Results Arsenic trioxide proliferation of NB4 and HL60 cells with similar sensitivity. As2O3 induced apoptosis of NB4 cells, but induced HL-60 differentiation to mature stage. Western blot detection and RT-PCR results showed that As2O3 treatment caused up-regulation of Bax, caspase-3, Caspase-8, Caspase-9, CD11b mRNA levels, and protein levels of caspase-3, Caspase-8, Caspase-9 in both cell lines. The expression of survivin, C-myc, Bcl-2 and mutated p53 in NB4 cells treated with As2O3 significantly decreased. The expression of C-myc in HL60 cells treated with As2O3 significantly decreased, but survivin and Bcl-2 expression levels were not changed. Conclusion Arsenic trioxide can effectively inhibit proliferation of NB4 and HL60 cells, and induce apoptosis of NB4 cells, while induce HL-60 differentiation to mature stage. These effects may be associated with the altered expression of survivin, Bcl-2 and mutated p53 genes