Enhanced radiation-induced apoptosis of cancer cell lines after treatment with resveratrol.

A search for new agents that can sensitise cancer cells to ionising radiation is of continual interest and mainly due to the use of radiation in cancer therapy. Resveratrol, a powerful antioxidant has been shown to inhibit carcinogenesis in animal models. The purpose of this study was to examine whether resveratrol can sensitise cancer cells to X-irradiation. The human cancer cell lines examined were HELA (cervix carcinoma), K-562 (chronic myeloid leukemia) and IM-9 (multiple myeloma). The assays that were performed following X-irradiation (doses from 0 to 8 Gy) and/or incubation in the presence of resveratrol (concentrations ranging from 0 to 200 microM), were the following: trypan blue exclusion test to determine cell viability, cell morphology after May-Grunwald Giemsa staining, DNA profile analysis by flow cytometry to assess cell cycle distribution and the presence of the sub-G1 peak. The cell lines showed different radiation sensitivity (IM-9, high radiation sensitivity, K-562, intermediate radiation sensitivity and HELA, low radiation sensitivity) as seen by the X-irradiation dose related inhibition of cell growth and induction of apoptosis. The addition of resveratrol alone to the cell cultures induced apoptosis and inhibited cell growth from 50 (IM-9), 100 (EOL-1) or 200 microM (HELA) resveratrol concentrations. Concomitant treatment of the cells with either resveratrol and X-irradiation induced a synergical effect at the highest dose of 200 microM. These results show that resveratrol can act as a potential radiation sensitiser at high concentrations. Further studies need to address the toxicity of resveratrol on normal cells.