Modulation of tumor cell metabolism by laser photochemotherapy with cisplatin or zoledronic acid in vitro

Abstract

Background/Aim: Laser photochemotherapy is a new approach in cancer treatment using low-level laser therapy (LLLT) to enhance the effect of chemotherapy. Materials and Methods: In order to evaluate the effect of LLLT on tumor cells, HeLa cells were treated with cisplatin or zoledronic acid (ZA) followed by LLLT. Cell viability was evaluated with 2,3-bis-(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide assay. Oxidative phosphorylation and glycolysis were measured using extracellular flux analysis. Immunocytochemistry of heat-shock protein 70 (HSP70) and western blot analysis were performed. Results: LLLT alone increased viability and was associated with lower oxidative phosphorylation but higher glycolysis rates. Cisplatin and ZA alone lowered cell viability, glycolysis and oxidative phosphorylation. This effect was significantly enhanced in conjunction with LLLT and was accompanied by reduced oxidative phosphorylation and collapse of glycolysis. Conclusion: Our observations indicate that LLLT may raise the cytotoxicity of cisplatin and ZA by modulating cellular metabolism, pointing to a possible application in cancer treatment.