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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。
This study aimed to observe the effects of chronic myeloid leukemia (CML) bone marrow mesenchymal stem cells (BMMSCs) on the proliferation and apoptosis of K562 cells and primary blast crisis CML leukemia cells and its possible mechanism and significance. K562 cells and primary blast crisis CML leukemia cells were co-cultured with different groups of BMMSCs respectively. Cell proliferation was detected by MTT assay. Apoptosis and mitochondrial membrane potential were measured by flow cytometry. Western blot was used to detect the expression of caspase- 8, caspase-9, activated caspase-3 expression. The results showed that BMMSC could not inhibit the proliferation of primary acute myeloid leukemia cells in CML blast crisis and had only mild inhibitory effect on K562. BMMSC increased the survival rate of adriamycin-treated K562 cells in CML blast crisis and protected K562 and Primary CML-Bp myelomonocytic mononuclear cells inhibited doxorubicin-induced apoptosis (P <0.05). Compared with chronic myelogenous leukemia (CML) and normal BMMSCs, BMMSC showed the strongest protective effect on leukemic cells in CML blast crisis (P <0.05). Detection of K562 in BMMSC coculture group in CML blast crisis showed that active Caspase-3 expression was significantly down-regulated and caspase-9 expression was significantly increased in K562 + ADM group (P <0.05). CONCLUSION: BMMSC can down-regulate the apoptosis of leukemic cells induced by doxorubicin in CML blast crisis. The mechanism may be related to the decrease of mitochondrial membrane potential, stabilization of caspase-9 inactivation and down-regulation of caspase-3 protein.