Phototherapy alters the oncogenic metabolic activity of the breast cancer cells.

Metabolic reprogramming in cancer cells is a strategy to attain a high proliferation rate, invasion, and metastasis. In this study, the effects of phototherapy at different wavelengths were investigated on the metabolic activity of the breast cancer cells.The states of the MCF7 cells proliferation and viability were measured by the MTT assay. Glucose consumption and the lactate formation in the LED-irradiated cells culture were analyzed by biochemical assay kits. The Amino acid concentration in the culture media of the MCF7 cells was analyzed using HPLC. Moreover, the gene expression of some glycolytic, TCA cycle and pentose phosphate cycleenzymes were assessed by real time PCR.

Phototherapy at wavelength of 435 nm decreased the cell viability by 23% when the energy dose was 17.5 J/cm² compared to the control group. The expression of the LDHA and GLS was up-regulated in 629 nm-treated cells while the expression of these genes were down-regulated in the MCF7 cells irradiated at 435 nm in comparison with the control group. Consequently, the glucose consumption and the lactate formation were diminished respectively by 22% and 15% in the 435 nm-irradiated cells while the glucose consumption and the lactate formation were increased in the 629 nm-irradiated cells by 112% and 107% in comparison with the control group. In addition, the analysis of the glutamine concentration by the HPLC indicated that the blue light irradiation decreased the glutamine consumption while the red light increased it in comparison with the control group.