1,25-二羟基维生素D_3抑制K562细胞增殖及其机制

目的观察1,25二-羟基维生素D3〔1,25(OH)2D3〕对白血病细胞株K562增殖的影响并初步探讨其作用机制。方法间接免疫荧光法鉴定维生素D受体(VDR)在K562细胞的表达;四噻唑蓝法(MTT)、AO/EB、流式细胞PI单染分析细胞生长抑制率、细胞凋亡率及细胞周期;比色法检测凋亡信号蛋白———天冬酰胺特异酶切的半胱氨酸蛋白酶-3(Caspase-3)活性。结果①K562细胞核阳性表达VDR;②10-8mol.L-11,25(OH)2D3可明显抑制K562细胞增殖,促进凋亡,凋亡率从4.1%(对照组)增至26.5%,P<0.01;③1,25(OH)2D3作用后K562细胞的Caspase-3活性增加,P<0.05,提示细胞凋亡伴随着Caspaes-3活性升高。结论1,25(OH)2D3可明显抑制K562细胞增殖,促进细胞凋亡,其作用机制与Caspase-3活性增加相关。

Effects of 1α,25-Dihydroxyvitamin D3 on the proliferation and apoptosis of K562 leukemia cells and its mechanism

Aim To investigate effects of 1α,25-Dihydroxyvitamin D_3 on the growth inhibition,proliferation of K562 cells and to explore its mechanism. Methods The expression of vitamin D receptor(VDR) was indentified by indirect immunofluorescent stainings.Cell growth,proliferation,apoptosis and cells cycle were evaluated by MTT assay,acridine orange/ethidium bromide(AO/EB) and flow cytometry PI staining.The enzymatic activity of the caspases-3 class of K562 cells was determined by colorimetric assay.Results ① VDR was present in K562 cell nucleus;② 10~(-8) mol·L~(-1) 1,25(OH)_2D_3 could markedly inhibit K562 cells growth and induce cells apoptosiswith most of cells being arrested in G_2/M phase.The ratio of apoptosis increased from 4.1%(control group) to 26.5%(treatment group),P<0.01;③ The enzymatic activity of the caspases-3 class increased significantly in cells treated with 1α,25-Dihydroxyvitamin D_3,P<0.05,implying the development of apoptosis accompanied with the increasing caspases-3 activity.Conclusion 1α,25-Dihydroxyvitamin D_3 exhibited obvious inhibitory effects on the cell proliferation,cell cycle and induced apoptosis in K562 cells.The mechanism appears to involve enhancing caspase-3 class activity.