Effect of gold nanocomposite bearing HIF-1α siRNA on radiotherapy in nasopharyngeal carcinoma cell

Purpose: To investigate the effect of gold nanocomposite carrying hypoxia-inducible factor-1α (HIF-1α) siRNA on radiosensitivity of nasopharynx cancer (NPC) cells. Methods: Gold nanocomposite (AuNRs-(PEI-PEG)/RGD) or (AuPPR) was first synthesized and its cytotoxicity was evaluated. Then, the expression of HIF-1α in hypoxic NPC cells was assessed. In addition, the radiation sensitivity of AuPPR bearing HIF-1α siRNA on the cells was examined under xray exposure. Result: Gold nanocomposite (AuPPR) carrying HIF-1α siRNA (AuPPR-HIF-1α siRNA) significantly down-regulated HIF-1α expression. Under irradiation treatment, AuPPR-HIF-1α siRNA significantly enhanced apoptosis of NPC cells by 33.76 ± 3.65 %, when compared to the control and simple AuPPR group (22.5 ± 4.16 %, p < 0.01). Furthermore, cell cycle was significantly blocked in the sub-G1 phase in AuPPR-HIF-1α siRNA radiotherapy groups, indicating severe cell damage. Conclusion: This study has demonstrated that AuPPR-HIF-1α siRNA is effective in improving the radiosensitivity of nasopharyngeal carcinoma cells under hypoxia, and therefore can potentially be used to improve the radiotherapy of this carcinoma