Synergistic inhibitory effect of resveratrol and TK/GCV therapy on melanoma cells.

PURPOSE: To investigate the synergistic effect of resveratrol on the bystander effect of TK/GCV suicide gene system in melanoma cells. METHODS: The effect of resveratrol on the growth of B16 cells and the synergistic effect of resveratrol with or without GCV were detected by MTT assay and high content screening assay. The effect of resveratrol on GJIC function was detected by flow cytometry combined with fluorescence tracer and fluorescence microscope, and the expression of gap junction protein was detected by western blotting. Synergistic killing effect of resveratrol plus TK/GCV was tested in vivo using transplanted melanoma model. RESULTS: In vitro, resveratrol can enhanced GJ function and upregulated Cx32 and Cx43 protein expression in B16 cells. Resveratrol synergized with GCV to kill mixed B16 melanoma cells (20% TK(+) cells and 80% TK(-) cells) and to improve apoptosis rate of TK(-) cells (the bystander effect of TK system), and the synergistic action was reversed by the GJ inhibitor AGA. In vivo, when B16 cells were mixed with 30% TK(+) B16 cells, significantly reduced tumor weight and volume were observed after combinational treatment with resveratrol plus GCV as compared with GCV or resveratrol treatment alone. CONCLUSIONS: Resveratrol could synergistically enhance the killing effect of TK/GCV suicide gene system in melanoma B16 cells and transplanted melanoma. It might be a promising adjuvant of TK/GCV therapy.