survivin基因在地塞米松诱导CEM细胞凋亡过程中的变化(英文)

Expression of survivin gene in apoptosis induced by dexamethasone in CEM cells

摘要:

目的：糖皮质激素诱导白血病细胞凋亡的确切机制尚不清楚。存活素(survivin)是凋亡抑制蛋白(inhibitorsofapoptosisprotein,IAPs)家族的成员,与凋亡抑制、肿瘤细胞增殖、血管形成及耐药正相关。该研究探讨地塞米松诱导急性淋巴白血病细胞系CEM凋亡过程中survivin基因的表达。方法：将在体外培养的对数生长期的CEM细胞浓度调至2×105个/mL,接种于24孔培养板中,用终浓度分别为0.1,0.5,1,5,10μM地塞米松处理,以不加任何药物的CEM细胞作为对照组,培养后24,48,72h取样。台盼蓝拒染法测定细胞活力,流式细胞仪解析地塞米松诱导CEM细胞凋亡,WesternBlot、RT-PCR方法分别检测survivin蛋白和基因的表达。结果：0.1,0.5,1,5,10μM地塞米松于48h开始明显抑制CEM细胞的生长,抑制效果呈时间、剂量依赖方式。随着地塞米松剂量增大,凋亡细胞比例逐渐增加。5μM地塞米松处理12~48h,凋亡细胞比例从14.9%升至46.2%。5μM地塞米松处理降低了survivin蛋白表达,12h降至对照组的54.6%,24h降至45.5%,48h降至15.8%,72h降至9.7%。survivinmRNA表达在5μM地塞米松处理后也被下调,处理后6h降至对照组的76.4%,12h降至67.3%,24h降至55.0%,36h降至49.9%,48h降至38.3%,72h降至18.3%。结论：地塞米松诱导CEM细胞凋亡与下调survivin基因表达有关。

Abstract:

OBJECTIVE: The precise mechanism of glucocorticoid-induced apoptosis has not yet been elucidated. Survivin, a member of the inhibitors of apoptosis protein family, correlates with inhibition of apoptosis, proliferation, angiogenesis and multiple drugs resistance. This study aimed to investigate the variation of the survivin gene expression in apoptosis induced by dexamethasone (Dex) in the human T-lineage acute lymphoblastic leukemia (ALL) cell line, CEM-WT cells. METHODS: The logarithmically growing CEM cells cultured in vitro (cell density 2×105/mL) were exposed to 0.1, 0.5, 1, 5, and 10 μM Dex, then were collected 24, 48 and 72 hrs later. Untreated CEM cells were used as Controls. The cell viability was determined by trypan blue dye exclusion. Apoptosis was evaluated by morphology and flow cytometry. Survivin protein and gene were analyzed by Western Blot and RT-PCR. RESULTS: CEM cells growth was obviously inhibited by 0.1, 0.5, 1, 5, and 10 μM Dex from 48 hrs. The inhibition effect was dose-and time-dependent. CEM cells treated with Dex (≥5 μM) exhibited typical apoptotic features. The apoptosis increased after 5 μM Dex treatment in a time-dependent manner, with the apoptosis percentage increasing from 14.9% (12 hrs) to 46.2% (48 hrs). Compared with that of the Control group, the expression of survivin protein was down-regulated, with the expression rate of 54.6%, 45.5%, 15.8% and 9.7% respectively at 12, 24, 48 and 72 hrs after 5 μM Dex treatment. 5 μM Dex treatment also resulted in a decrease of survivin mRNA expression. The survivin mRNA expression was 76.4%, 67.3%, 55.0%, 49.9%, 38.3% and 18.3% of the Control respectively at 6, 12, 24, 48 and 72 hrs after Dex treatment. CONCLUSONS: Apoptosis induced by Dex in CEM cells is associated with downregulation of the survivin expression.