抑制LRP16基因表达增加了肿瘤细胞辐射敏感性

Improvement of radiation sensitivity by inhibiting expression of the human LRP16 gene in tumor cells

目的:探索抑制LRP16基因表达对肿瘤细胞辐射治疗敏感性的影响。方法:采用逆转录病毒介导的小干扰RNA策略,建立了LRP16基因表达被稳定抑制的MCF7及HeLa细胞系,采用电离辐射及紫外线(UV)分别照射LRP16基因被稳定抑制表达的MCF7和HeLa细胞,于照射后不同的时间点进行Hoechst33342染色以检测细胞凋亡率,并进行DNA片段化分析;胎盘蓝染色检测不同时间点的细胞死亡率。结果:照射后2～10h之间,LRP16基因表达抑制组细胞的凋亡率明显高于对照组(P<0.05);照射后10h胎盘蓝方法计数死活细胞,发现LRP16基因抑制组细胞的死亡率>40%,而对照组的死亡率在15%～20%之间;24h计数细胞死亡率发现LRP16基因抑制组细胞与对照组细胞差别不明显(P>0.05)。结论:抑制LRP16基因在肿瘤细胞中的表达增加了瘤细胞的辐射治疗敏感性,其机制可能是通过抑制LRP16基因表达干预了辐射诱导DNA损伤反应的早期信号途径。

Objective:To explore the effect of inhibiting LRP16 gene expression on the tumor cells to radiation sensitivity. Methods:By adopting the retrovirus-mediated small interfering RNA (siRNA) strategy, MCF-7 and HeLa cells with endogenous LRP16 gene suppression were established. At different time point after exposure to ionizing radiation or ultraviolet (UV) of cells, apoptosis was detected by Hoechst 33342 staining and DNA fragmentation analysis, live cells were numerated by Tanpan Blue staining.Results:After two to ten hours of exposure to radiation, apoptotic cells in the group with expression suppression of the human LRP16 gene significantly increased compared with their controls(P<0.05). At the 10 h time point after exposure, 40 percent cells with LRP16 gene suppression were observed to death, while 15 to 20 percent death cells were detected in the control groups. But the significant difference of apoptotic or death cells between the LRP16-inhibitory cells and the controls was not observed at the 24 h time point after exposure. Conclusion:Taken together, inhibition of the LRP16 gene expression sensitizes tumor cells to radiation treatment. And the mechanism may involve in the disruption of the early-stage DNA damage response signaling pathway by interfering LRP16 expression.