Sunitinib with photoirradiation-mediated reactive oxygen species generation induces apoptosis of renal cell carcinoma cells

Background: Photodynamic therapy is a clinically approved, minimally invasive,therapeutic procedure used for the treatment of several cancers. In recent years, sunitinib, one of the tyrosine kinase inhibitors, has also attracted attention as a novel photosensitizer. However, there is currently no data available on the combined cytotoxic effects of sunitinib and photoirradiation on renal cell carcinoma including how the treatment induced cellular toxicity. Methods: In the present study, we used sunitinib as a photosensitizer and evaluated the effects of sunitinib and photodynamic therapy treatment on renal cancer cell lines, including the induction of cell death. Results: Our study showed that treatment with sunitinib and photoirradiation at 8 mW/cm(2) for 30 min resulted in the production intracellular reactive oxygen species (ROS), which is indicated by the increase in mRNA expression levels of PAI-1, NF-kappa beta, and Caspase-3. An increase in rate of apoptotic reaction and increase in the expression level of apoptotic marker were also observed when cells undergo treatment with sunitinib and photoirradiation. Conclusions: Our findings suggest that combining photodynamic therapy with sunitinib represents a minimally invasive therapeutic procedure with cancer selectivity for renal cell carcinoma.