抑制LRP16基因的表达降低了MCF-7细胞对5-FU的杀伤敏感性

目的:探讨LRP-16基因对MCF-7细胞增殖的影响及其潜在的临床意义。方法:既往用逆转录病毒介导RNA干扰的方法,已构建了能不同程度抑制MCF-7细胞LRP16基因表达的细胞系pL668(抑制率60%)、pL374(抑制率90%)及其阴性对照pGFPi细胞系。应用台盼蓝排斥实验法观察三种细胞增殖速率和用细胞周期S期特异性的化疗药物5-FU诱导pL374、pGFPi细胞的死亡情况。结果:pGFPi、pL668、pL374三种转染细胞的增殖能力依次降低(P<0.05)。5FU作用于细胞后,pGFPi从24h开始即有10%以上的细胞死亡,48h死亡率达20%,72h死亡率为75%,至96h基本全部死亡;而pL374在72h以后死亡率才明显上升,96h死亡率达30%。结论:抑制LRP16基因表达,可有效抑制MCF7细胞的增殖,并降低了细胞对5-FU的杀伤敏感性。表明LRP16基因参与了MCF-7细胞周期转化的调节,可能作用于G1/S关卡点。提示该基因在肿瘤的发生和发展过程中发挥重要的作用,可能是雌激素依赖性乳腺癌的一个良好治疗靶标。

Suppression of LRP16 gene expression decreased the lethal sensitivity of MCF-7 cell line to 5-FU

objective:To explore the effect of the human gene LRP16 on MCF-7 cell proliferation and the potential clincial significance. Methods:Three MCF-7 human breast cancer cell lines with different LRP16 expression level by retrovirus-mediated siRNA strategy, pL374(suppressive rate 90%), pL668(suppressive rate 60%) and pGFPi(negative control) were used as model cells. Cell proliferation assay were performed by using trypan blue exclusion method. 5-FU, a typical S phase specific chemotherapeutic drug, was used to induced cell death. The cell viability of the pL374, pGFPi cell lines was also assayed. Results:The proliferative ability of pGFPi, pL668 and pL374 cell lines were significantly decreased in order(P<0.05). After being treated with 5-FU, pGFPi cells died more than 10 percent at 24 h time point, 20 percent at 48 h,75 percent at 72 h and nearly 100 percent at 96 h. In contrast with the control cells, 5-FU did not markedly induced the pL374 cells death until 72 h, only 30 percent at 96 h.Conclusions:Inhibition of LRP16 gene expression in MCF-7 cells effective suppressed cells proliferative ability and decreased the lethal sensitivity to 5-FU. These results indicated that LRP16 gene involves in the regulation of MCF-7 cell cycle transition, possibly by modulating the G_(1)/S checkpoints. Taken together, LRP16 gene might play important roles in tumorgenicity and progression, and maybe a candidate therapeutic target of estrogen-dependent breast cancer.