Enhancement of Photodynamic Therapy Induced Cytotoxicity in K562 Cells by Genistein

Genistein (GEN) is one of the major soy isoflavones. It is particularly effective in quenching free radicals generated by toxic agents. On account of its anti-oxidant property, it may protect cancer cells from free radical damage in photodynamic (PDT) during which reactive oxygen species (ROS) production was stimulated leading to irreversible tumor cell injury. In this study, the influence of genistein on K562 cells in 5-aminolevulinic acid (ALA)-based PDT is demonstrated The results showed that genistein inhibits cell proliferation and enhances cell apoptosis in ALA-PDT on K562 cells. NaN3, a singlet oxygen quencher, suppresses the genistein-induced cell apoptosis. In conclusion, genistein enhances the PDT-induced cytotoxicity in K562 cells and singlet oxygen was involved in this process.