OBJECTIVETo study the radiosensitizing effect of resveratrol on hypopharyngeal carcinoma cell line FADU in vitro.

METHODSHypopharyngeal carcinoma cell line FADU was cultured in in vitro DMEM. Its inhibition on cell proliferation was detected using cytotoxicity test (MTT assay). The cell survival curve was drawn using clone formation to obtain sensitive enhancement ratio (SER). Changes of the cell cycle and cell apoptosis were analyzed using flow cytometry (FCM).

RESULTSResults of MTT showed the inhibition of resveratrol on FADU cells increased along with its concentrations (P < 0.05). Results of clone formation indicated the surviving fraction at 2 Gy (SF2) was 0.717 ± 0.062 in the irradiation group, and 0.426 ± 0.035 in the resveratrol plus irradiation group (with SER ranged 1.684 ± 0.178) with statistical difference (P = 0.007). Results of FCM showed that after radiation of 4 Gy radiation, cells at G2/M phase arrest increased, but cells at G1 decreased. After radiation of resveratrol for 24 h, cells at G1 decreased, but cells at G2/M phase and S phase arrest increased. When 4 Gy radiation combined resveratrol was used, cells at G2/M phase arrest significantly increased, but cells at G1 significantly decreased. The apoptosis rate was 1.94% ± 1.65% in the control group, 4.56% ± 0.92% in the irradiation group, 2.03% ± 1.46% in the resveratrol group, and 23.11% ± 7.22% in the resveratrol plus irradiation group. There was statistical difference between the resveratrol plus irradiation group and the rest 3 groups (P < 0.05).

CONCLUSIONResveratrol could enhance the radiosensitivity of hypopharyngeal carcinoma FADU cells in vitro possibly by inducing cell apoptosis and causing changes in the cell cycle distribution.