短发夹状RNA对卵巢癌细胞survivin mRNA表达及紫杉醇药物敏感性的影响

目的观察表达短发夹状RNA(shRNA)的mU6/survivin质粒转染卵巢癌细胞株OVCAR3细胞后,对OVCAR3细胞survivin mRNA表达的抑制作用,以及对OVCAR3细胞紫杉醇药物敏感性的影响。方法将表达绿色荧光蛋白的pEGFPC2质粒与脂质体按不同比例转染OVCAR3细胞,流式细胞仪检测其转染效率。根据转染效率最高时pEGFPC2质粒与脂质体的比例,将mU6/survivin质粒转染入OVCAR3细胞。实验分为3组未转染组、脂质体组、转染组,RT-PCR技术检测3组OVCAR3细胞中survivin mRNA的表达,流式细胞仪分析细胞周期及细胞凋亡率的变化。四甲基偶氮唑蓝(MTT)比色法检测3组OVCAR3细胞对紫杉醇的50%抑制浓度(IC50)。结果pEGFPC2质粒与脂质体按1∶2比例转染OVCAR3细胞时其转染效率最高,达23.6%。将mU6/survivin质粒与脂质体也按1∶2比例转染OVCAR3细胞24h后,未转染组、脂质体组、转染组细胞survivin mRNA的相对含量分别为0.81±0.05、0.79±0.12、0.26±0.04,转染组survivin mRNA相对含量下降至未转染组的32%,两组比较,差异有统计学意义(P<0.01)。转染组转染24h后,细胞凋亡率为(31.9±1.2)%,明显高于未转染组的(4.9±0.7)%和脂质体组的(5.6±0.5)%(P=0.000);转染组细胞周期被阻滞于G0/G1期,G2/M期减少,分别与未转染组比较,差异有统计学意义(P<0.01)。MTT比色法检测结果显示,未转染组、脂质体组、转染组OVCAR3细胞对紫杉醇的IC50分别为(0.305±0.032)、(0.157±0.031)、(0.019±0.001)μmol/L,转染组OVCAR3细胞对紫杉醇的IC50降低为未转染组的1/16,两组比较,差异有统计学意义(P=0.000)。结论shRNA可有效抑制卵巢癌细胞survivinmRNA的表达,并显著提高了卵巢癌细胞对紫杉醇的药物敏感性。

Influence of short hairpin RNA on survivin mRNA expression and chemosensitivity to paclitaxel in ovarian cancer cells

OBJECTIVE: To investigate the influence of short hairpin RNA (shRNA) expression plasmid against gene survivin (mU(6)/survivin) on survivin mRNA expression and chemosensitivity to paclitaxel in ovarian cancer cells OVCAR3. METHODS: OVCAR3 cells were transfected with plasmid pEGFPC(2) formulated with lipofectamine 2000 at different concentrations. The transfection efficiency was examined by flow cytometry. The expression of survivin mRNA of OVCAR3 cells after transfection with the plasmid mU(6)/survivin with the high efficiency ratio was observed by RT-PCR. The effect of the plasmid on the cell cycle and apoptosis was analyzed by flow cytometry. The chemosensitivities of transfected cells to paclitaxel were determined by methyl thiazolyl tetrazolium (MTT). RESULTS: The optimal transfection efficiency was obtained when pEGFPC(2): lipofectamine 2000 was 1: 2. Compared with the non-transfected groups, 0.81 +/- 0.05, the mRNA of survivin in OVCAR3 cells was reduced clearly after transfection with mU(6)/survivin, 0.26 +/- 0.04. shRNA reduced the expression level of survivin mRNA to 32% of non-transfected groups (P < 0.01). The apoptotic rate of survivin shRNA group reached (31.9 +/- 1.2)%, which was much higher than those of non-transfected (4.9 +/- 0.7)% and lip alone groups (5.6 +/- 0.5)% (P = 0.000). Cell cycle analysis showed that survivin shRNA induced accumulation of cells in G(0)/G(1) phase with a decrease of cells in G(2)/M phase after being cultured for 24 hours compared with non-transfected group (P < 0.01). MTT results showed that the 50% inhibiting concentration (IC(50)) of paclitaxel in non-transfected, lip alone and survivin shRNA transfected groups was (0.305 +/- 0.032), (0.157 +/- 0.031), and (0.019 +/- 0.001) micromol/L respectively. Compared with non-transfected group, shRNA increased the chemosensitivity of OVCAR3 cells to paclitaxel by 16 fold (P = 0.000). CONCLUSION: Sequence specific shRNA targeting survivin can effectively suppress the expression of survivin mRNA and enhance the chemosensitivity to paclitaxel in ovarian cancer cells significantly.