枸杞多糖单独或联合TRAIL对MLL基因重排急性淋巴细胞白血病细胞凋亡的影响

Influence of LBP alone or Combined with TRAIL on Apoptosis of MLL Rearranged Leukemic Cells

目的:研究枸杞多糖(LBP)单独或联合肿瘤坏死因子相关的凋亡诱导配体(TRAIL)对MLL基因重排白血病细胞株凋亡的影响,并探讨其联合作用后细胞凋亡通路。方法:选取MLL急性淋巴细胞白血病细胞株KOCL44和KOCL45作为研究对象,设置对照组和实验组。采用台盼蓝拒染法检测细胞存活率;Annexin-V/PI双染色流式细胞术检测细胞早期凋亡情况及药物作用后细胞表面死亡受体的表达水平;Western blot法检测caspase-8、Bid、caspase-3、caspase-9、BAD、BCL-2以及线粒体Cyto-C和胞浆内Cyto-C的表达水平。结果:LBP与TRAIL联合处理对KOCL44、KOCL45细胞株生长有抑制作用,2药联合有协同作用,Annexin-V/PI双染流式细胞术检测结果与此一致。LBP与TRAIL联合处理KOCIA44、KOCL45细胞株后细胞表面DR4未见明显表达,而DR5受体表达明显增强,caspase-8、BID、caspase-3、caspase-9和BAD明显活化、BCL-2受抑,呈作用时间依赖趋势。KOCL44和KOCL-45的线粒体Cyto-C表达随作用时间延长而下降(r=-0.95;r=-0.866),而KOCL44和KOCL45的胞浆内Cyto-C表达随作用时间延长而增强(r=0.883;r=0.903)。结论:LBP与TRAIL联合处理KOCL44和KOCL45细胞株后,细胞凋亡明显,二者上调细胞表面TRAIL死亡受体DR5表达,并激活caspase与线粒体通路,从而增强MLL基因重排急性淋巴细胞白血病细胞株对TRAIL诱导凋亡的敏感性。

Objective:To investigate the effect of lycium barbarum polysaccharide (LBP) alone or combined with tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) on the apoptosis of leukemia cell lines with MLL generearrangement, and to explore the cell apoptotic pathway after the combined action. Methods:MLL-ALL cell line KOCL44 and KOCL45 were selected as the research object,then the control and experimental groups were set up. The cell survival rate was measured by the trypan blue dye exclusion method,the cell early apoptosis and expression of death receptors on the cell surface were detected by flow cytometry with Annexin-V/PI double staining. The protein level of caspase-8,BID, caspase-3,caspase-9,BAD,BCL-2,as well as mitochondrial and cytosol Cyto-C were detected by Western blot. Results:LBF combined with TRAIL inhibited the growth of KOCL44 and KOCL-45 cells and showed the synergistic effect,the results of flow cytometry with Amnexiu V/PI double staining were consistent with above-mentioned results. After treatment of KOCL44 and KOCL45 cells with LBF plus TRAIL,the significant expression of DR4 on cell surface was not found, while the expression of DR4 receptor was enhanced significantly,the pro-apoptotic proteins including caspase-8,BID, caspase-3,caspase-9 and BAD were activated significantly and BCL-2 was suppressed significantly with time-dependent manner. The expression of mitochondria cyto-C in KOCL44 and KOCL45 decreased along with prolonging of treatment time (r=-0.95,r=-0.866),while the expression of cytosol cyto-C in KOCL44 and KOCL45 increased along with prolonging of treatment time (r=0.883,r=0.903). Conclusion:The combination of LBP and TRAIL significantly increases the apoptosis of KOCL44 and KOCL45,and the LBP and TRAIL can up-regulate the expression of TRAIL death receptor-DR5 on the cell surface,activate the pathway of caspase and mito-chrondia mitachondria,thus enhance the sensitivity of KOCL44 and KOCL45 to TRAIL induced apoptosis through both mitochondrial and apoptotic pathway.