[LY294002 Enhaces Chemosensitivity of K562 Cells to Daunorubicin].

To investigate the proliferation inhibition and pro-apoptosis effect of LY294002 (PI3K/AKT inhibtor) combined with daunorubicin (DNR) on the chronic myeloid leurenia cell line K562 and its possible mechanisms.The effect of LY294002 and DNR on the proliferation of K562 cells in different treating time and concentration were measured by MTT assay. The cell cycle was determined by flow cytometry, the mRNA and protein expression of SKP2 , P27, BCL-2 and BAX were determined by RT-PCR and Western blot.LY294002 and DNR were able to inhibit the growth of K562 cells and promote apoptosis in time- and concentration-dependent manner (P＜0.05), both the cell proliferation-inhibiting rate and apoptosis rate in combination therapy group were higher than that in DNR-monotherapy group (P＜0.05). After K562 cells treated by LY294002 combined DNR for 36 h, the cells were statistically significantly reduced in G2/M phase (P＜0.05), as compared with control group and DNR group. Compared with DNR group, the cell level of G0/G1 phase rased (P＜0.05) and cell level of S phase decreased (P＞0.05). Compared with DNR group, the expresson of SKP2 and BCL-2 mRNA decreased, and the expression of P27 mRNA increased in the combination therapy group (P＜0.05). The expression of BAX mRNA was not significantly different between different groups. The same result was found in the protein expression.LY294002 has the sensibilizative effect on DNR chemotherapy, which may be relative with blocking the cell cycle and inducing cell apoptosis.LY294002增强K562细胞对柔红霉素敏感性的研究.探讨PI3K/Akt抑制剂LY294002联合蒽环类化疗药物柔红霉素（DNR）对慢性髓系白血病细胞株K562细胞增殖的抑制作用、促凋亡作用及其相关机制.应用MTT法检测LY294002和DNR在不用浓度、不同作用时间点对K562细胞增殖的影响，流式细胞术分析细胞周期的变化，应用RT-PCR和Western blot法检测LY294002和DNR对K562细胞SKP2、P27、BCL-2和BAX2基因和蛋白表达的影响.LY294002联合DNR能够抑制K562细胞的生长并促进细胞凋亡，且具有浓度及时间依赖性（P＜0.05）；2药联合后细胞增殖抑制率及细胞凋亡率明显增加（P＜0.05）。2药联合作用于K562细胞36 h，随着浓度的增加其G2/M期细胞显著减少（P＜0.05），与DNR单药比较，G0/G1期细胞数增加 （P＜0.05），S期细胞减少，但差异无统计学意义。2药联合作用后，SKP2及BCL-2的mRNA表达量降低，P27 mRNA表达增高，差异具有统计学意义。BAX的表达在各实验组中的差异无统计学意义。相应的蛋白表达水平与之相符.LY294002对DNR的化疗作用有增敏效果，其作用机制可能与阻滞细胞周期及诱导细胞凋亡有关.