急变期慢性髓系白血病骨髓间充质干细胞下调白血病细胞凋亡

本研究旨在观察慢性髓系白血病（CML）骨髓间充质干细胞（BMMSC）对K562细胞和原代急变期CML白血病细胞增殖和凋亡的影响及其可能的机制及意义.K562细胞和原代急变期CML白血病细胞分别与不同组别的BMMSC共培养,应用MTT法检测细胞增殖,流式细胞术检测细胞凋亡及细胞线粒体膜电位,Western blot检测凋亡相关蛋白caspase-8、caspase-9、激活的caspase-3的表达.结果表明：CML急变期BMMSC不能抑制原代CML急变期白血病细胞的增殖,对K562仅有轻度的抑制作用;CML急变期BMMSC提高阿霉素处理后的K562细胞的存活率,并保护K562及原代CML-Bp骨髓单个核细胞,抑制阿霉素诱导的细胞凋亡（P＜0.05）;与CML慢性期及正常组BMMSC相比较,CML急变期BMMSC对白血病细胞的保护作用最强,其细胞共培养组的细胞线粒体膜电位下降最少（P＜0.05）;检测CML急变期BMMSC共培养组的K562显示,活性Caspase-3表达均较单独K562＋ ADM组明显下调,caspase-9表达显著增加（P＜0.05）.结论：CML急变期BMMSC下调阿霉素诱导的白血病细胞的凋亡,其机制可能与抑制细胞线粒体膜电位的下降,稳定caspase-9蛋白非活性的表达和下调caspase-3蛋白的激活有关.

BMMSC from Blastic Phase CML Down-regulate Leukemia Cell Apoptosis

The purpose of this study was to investigate the effect of bone marrow mesenchymal stem cells （BMMSC） from patients with chronic myeloid leukemia （CML） in blastic phase （Bp） on K562 cells and the primary CML-Bp cells,and to explore its potential mechanisms.K562 cells and primary CML-Bp cells were co-cultured with BMMSC of different groups; the cell proliferation was detected by MTT method,the cell apoptosis rate and mitochondtial membrane potential were measured by flow cytometry,the expression levels of Caspase-8,Caspase-9,and activated Caspase-3 in cells were measured by Western blot.The results showed that the CML-Bp BMMSC could enhance the survival rate of K562 cells treated with adviamycin （ADM） and display protective effect on K562 cells and primary CML-Bp mononuctear cells,inhibited ADM-induced leukimia cell apoptosis （P 〈 0.05） ; as compared with CML-chronic phase （CML-Cp） BMMSC and normal BMMSC,the CML-Bp BMMSC showed the highest protective effect on leukemic cells,the mitochondrial membrane potential of co-cultured cells slightly droped （P 〈 0.05）.In the CML-Bp BMMSC cultured with K562 cells,the expression level of caspase-3 was more down-regulated than that in K562 alone plus ADM group,while the expression of caspase-9 significantly increased （P 〈 0.05）.It is concluded that the CML-Bp BMMSC down-regulates ADM-induced leukemia cell appoptosis,its mechanism may relate with the inhibition of mitochondrial membrane potential drop,the stabilization of unactive expression of caspase-9 and down-regulation of caspase-3 expression.