硒酸酯多糖通过下调mdr1/P-gp表达逆转K562/ADM细胞凋亡抑制

Kappa-selenocarrageenan overcomes apoptosis resistance in multidrug-resistant K562/ADM cells by down-regulating expression of mdr1 gene and its product P-glycoprotein

目的:研究硒酸酯多糖(Kappa-selenocarrageenan,KSC)对多药耐药K562/ADM细胞的诱导凋亡效应及其分子机制。方法:以白血病多药耐药细胞K562/ADM为KSC作用的靶细胞,用MTT比色法检测细胞增殖活性,形态学、DNA片段化和流式细胞术(FCM)观察细胞凋亡;RT-PCR检测mdr1基因和Caspase-3基因mRNA的表达;FCM测定P-gp蛋白表达水平和Caspase-3活性。结果:KSC显著抑制K562/ADM细胞增殖,KSC诱导后K562/ADM细胞出现典型的凋亡形态学变化、DNA片段化和亚G1期细胞群等特征性改变。KSC下调K562/ADM细胞mdr1基因表达、抑制P-gp合成,并上调caspase-3基因表达、增强caspase-3活性。结论:KSC通过下调mdr1/P-gp表达逆转K562/ADM多药耐药细胞的凋亡抑制。

Objective ： To explore the apoptotic effect of Kappa - selenocarrageenan （ KSC ） on multidrug - resist- ant leukemia K562/ADM cells and the possible new molecular regulating mechanisms. Methods： Human multidrug -resistant leukemia cell line K562/ADM overexpressing mdrl gene was used as the target cells. The cell proliferating activity was assessed with a MTF colorimetric assay. Cytomorphology, DNA fragmentation and flow cytometric analysis were employed to confirm the apoptosis of K562/ADM cells, The expression of mdrl and caspase - 3 mRNAs was detected with RT- PCR, and the P -glycoprotein （P -gp） expression and caspase -3 activity were measured using flow cytometry. Results ： KSC inhibited the proliferation of K562/ADM cells, and the KSC - induced apoptosis of K562/ADM cells was ensured by the appearance of typical apoptotic morphological changes, DNA fragmentation （ DNA ladder） and increased sub - G1 cell population. KSC down - regulated the expression of mdrl mRNA and its product P - gp, and synchronously up - regulated the expression of caspase - 3 mRNA and caspase - 3 activity in K562/ADM cells, Conclusion： KSC inhibits the expression of mdrl/P-gp to overcome the P-gp -mediated apoptosis resistance in drug- resistant K562/ADM cells.