Chiral ruthenium(ii) complex as potent radiosensitizer of (125)I through DNA-damage-mediated apoptosis

A chiral ruthenium(ii) complex, Λ-[Ru(bpy)(2)(o-tFMPIP)] (ClO(4))(2) (o-tFMPIP = 2′-trifluoromethylphenyl) imidazo [4,5-f][1,10]phenanthroline, was prepared and evaluated for its enhancement of the radiosensitivity of (125)I seeds. The synthetic Ru(ii) complex, LR042, effectively enhanced growth inhibition against HepG2 human hepatocellular liver carcinoma cells induced by (125)I seeds and consequently effectively promoted the apoptosis of tumor cells with increasing level of cleave-caspase-3. Furthermore, the results of immunofluorescence indicated that LR042 enhanced the phosphorylation of H2AX by (125)I seeds vigorously in response to damaged DNA. LR042 improved DNA damage induced by (125)I seeds, which resulted in apoptosis through the activation of the p53/AKT signal. In conclusion, synthetic LR042 can be further developed as a potential radiosensitizer of (125)I seed radiotherapy for cancer therapy.