Combined Treatment of Androgen-Independent Prostate Cancer Cell Line DU145 with Chemotherapeutic Agents and Lithium Chloride: Effect on Growth Arrest and/or Apoptosis

Hormone-independent prostate cancer cell lines are resistant to antineoplastic drugs, this study sought to determine the usefulness of lithium chloride as an inhibitor of glycogen synthase kinase-3β to increase the cytotoxic effect of doxorubicin, etoposide or vinblastine antineoplastic drugs on DU145 cells. Combination effect was assessed by using low and IC50 doses of drugs + lithium chloride. Subsequently, cell cycle analysis and p53 levels and its subcellular localization as a key regulator of cell cycle were assessed. Lithium chloride showed cytotoxic effect in a dose and time dependent manner (p<0.001). Both drugs doxorubicin and etoposide in combination with lithium chloride (LiCl) showed higher percent of cells in SubG1 compared to control (p<0.001). Combination of IC50 dose of doxorubicin and lithium chloride led to S phase arrest (p<0.001, compared to control, lithium chloride or doxorubicin alone). Moreover, G2/M arrest was significantly increased when low dose of doxo-rubicin and vinblastine were combined with lithium chloride (p<0.001, com