Alteration of tumor metabolism after radiotherapy

9668 Background: Cancer cells utilize anaerobic glycolytic way to compensate their faster metabolism when compared to normal cells. The purpose of this study was to investigate the effect of radiation on tumor metabolism. Methods: MCF-7 breast cancer cell lines were divided into 3 groups, including 2 control groups and aerobic study group (were irradiated 600 cGy by Co-60 teletherapy unit), incubated with radiolabelled glucose for 4 hours. One control group was for aerobic, and the other was for anaerobic group after KCN addition. Radiolabelled CO2 produced by the cells was isolated and collected in specially designed sintillation vials. In supernatant the measurements of other end-products of carbohydrate catabolism including lactate, pyruvate, acetate were performed on a liquid scintillation analyzer after they were collected via anion-exchange chromatography. Finally glucose in supernatant was measured enzymatically by glucose oxidase method. Additionally, in pellets protein was determined by modified Lowry method and glycogen by Hassid and Abraham's enzymatic method (glycogen consumption per 1000 cells for each hour). Results: Radiation significantly reduced the number of cells (12.3x106), KCN group and control groups included 46.3 x106and 41.3 x106respectively. Glycogen consumption and lactate production were significantly higher in anaerobic and radiation groups. Whereas CO2 production was significantly higher in control group (Table I). Taken all results together radiation lead tumor cells more anaerobic glycolysis with high glycogen consumption, high lactate production and low CO2 production. Conclusions: Radiation itself has led tumor cells to produce energy by anaerobic glycolysis, meaning radiation exposed cells become more hypoxic. In our knowledge, this is the first experiment showing anaerobic effect of radiation on tumor cell lines. The researchers should be aware of this effect of sublethal dose of radiation. No significant financial relationships to disclose.