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

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(P0.05). 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.