Utilizing metformin to enhance the efficacy of androgen-deprivation therapy in the treatment of prostate cancer.

22 Background: Prostate cancer (PCa) incidence varies by geographic location, with developed countries exhibiting higher levels of disease. Some attribute this to the “Westernized lifestyle” of high energy diets and limited physical activity with consequent obesity. Obesity and related diseases like diabetes, cause hyperinsulinemia, which upregulates pro-survival insulin/insulin-like growth factor signalling. Previous work shows diet-induced hyperinsulinemia enhances PCa tumor growth in vivo. Metformin, a diabetic treatment, reduces hyperinsulinemia, and also exhibits anti-neoplastic properties. We assessed the potential benefit of combining a standard PCa treatment (bicalutamide) with metformin in vitro and in vivo. Methods: The effect of bicalutamide and/or metformin on colony formation rates was assessed in LNCaP, PC3, DU145 and PC3AR2 PCa cell lines using clonogenic assay. Western blot and cell cycle analyses were used to elucidate mechanisms of interaction between the drugs. The combination treatment...