雷帕霉素逆转T-ALL Jurkat细胞对糖皮质激素耐药(英文)

目的探讨雷帕霉素能否有效逆转T细胞急性淋巴细胞白血病(T-ALL)Jurkat细胞对糖皮质激素(GC)的耐药。方法用10 nmol/L雷帕霉素(Rap组)、1μmol/L地塞米松(Dex组)、10 nmol/L雷帕霉素联合1μmol/L地塞米松(Rap+Dex组)和0.05%DMSO和0.01%乙醇(对照组)分别处理Jurkat细胞。MTT法检测细胞增殖;流式细胞术检测细胞周期和凋亡;Western blot法分析mTOR及细胞周期、凋亡相关蛋白表达情况。结果10 nmol/L雷帕霉素能有效抑制mTOR信号通路,逆转Jurkat细胞对GC耐药。雷帕霉素和地塞米松协同作用可有效上调细胞周期抑制蛋白p21和p27的表达,并协同下调细胞周期素D1的表达,从而阻抑细胞在G1期。雷帕霉素协同地塞米松,通过上调Bim表达,活化caspase-3,促进Jurkat细胞凋亡。结论雷帕霉素可有效逆转T-ALL Jurkat细胞对GC耐药。包含雷帕霉素和地塞米松的化疗方案有望成为治疗耐药T-ALL的有效方案。

Rapamycin sensitizes Jurkat T-ALL cells to dexamethasone-induced apoptosis

Objective To investigate the potential and mechanism of using rapamycin to restore the sensitivity of GC resistant Jurkat T-ALL cells to dexamethasone(Dex)treatment. Methods Jurkat cells were treated with 10 nmol/L rapamycin(Rap group),1 μmol/L Dex(Dex group),10 nmol/L rapamycin plus 1 μmol/L Dex(Rap + Dex group),or 0.05% DMSO plus 0.01% ethanol(Control group). Cell proliferation was detected by MTT test. Fluorescence-activated cell sorting(FACS)analysis was used to analyze apoptosis and cell cycles. Western analysis was performed to test the expression of the downstream effector proteins of mTOR and the cell cycle regulatory proteins as well as the apoptosis associated proteins. Results 10 nmol/L rapamycin markedly increased GC sensitivity in GC-resistant Jurkat T-ALL cells and this effect was mediated,at least in part,by inhibition of mTOR signaling pathway. Cell cycle arrest was associated with modulation of G1-S phase regulators. Co-treatment of rapamycin and Dex can induce a synergistic up-regulation of CDK inhibitors of p21,and p27 and a synergistic inhibition of Cyclin D1 expression. Rapamycin enhanced GC-induced apoptosis by synergistic up-regulation of pro-apoptotic proteins like caspase-3 and Bim. Conclusions The data suggest that rapamycin can effectively reverse GC resistance in T-ALL and this effect is achieved by inducing cell cycle arrested at G0/G1 phase and by activating the intrinsic apoptotic program. Therefore,the protocol of combining mTOR inhibitor with glucocorticoids treatment might be an attractive new therapeutic approach for GC resistant T-ALL patients.