Darinaparsin is a dimethylated arsenic linked to glutathione. It is cytotoxic to DU145, LNCaP, and PC3 prostate cancer cells (IC50s = 5-10 μM) and patient-derived primary prostate cancer cells (IC50s = 2.5-20 μM), as well as Jurkat T cell lymphoma and L540 Hodgkin lymphoma cells (IC50s = 2.7 and 1.3 μM, respectively). It decreases the tumor-initiating subpopulation in DU145 and PC3 cells and halts the cell cycle in the G2/M phase. Darinaparsin decreases transcription of Gli-2, a transcription factor that mediates Sonic hedgehog signaling, when used at a concentration of 1.5 but not 3 μM. It decreases SHP1 phosphatase activity and increases ERK phosphorylation. Darinaparsin reduces tumor growth in DU145 and PC3 prostate cancer mouse xenograft models when administered at a dose of 100 mg/kg every other day.
Darinaparsin-d5 is the isotope labelled analog of Darinaparsin. Darinaparsin is an arsenic cytotoxin that has been used in pharmacological activities to evaluate the effect on survival an radiosensitivity of tumor cells in vitro under normoxia and hypoxia and in vivo using xenograft models. Darinaparsin has significant and preferential cytotoxic and radiosensitizing effects on solid tumors as compared with normal cells.?? Darinaparsin may therefore increase the therapeutic index of radiation therapy and has near term translational potential.
