Purpose: The main objective of the current research work was to investigate the antitumor effects of papaverine in PC-3 human prostate cancer cells along with testing its toxicity in the normal human fibroblast (NHF) cells.
Methods: The cytotoxic effects of papaverine were examined by the MTT cell viability assay. Flow cytometry using annexin V-FITC/PI was used to study the effects on apoptosis, including its quantification. Effects on cell cycle progression were analyzed by flow cytometry while as effects on apoptosis-related proteins, NF-kB and PI3K/Akt pathways were estimated by Western blot assay.
Results: The results indicated that papaverine could induce significant, highly selective and dose-dependent cytotoxic effects in PC-3 cells without causing too much toxicity in normal cells. Papaverine also led to induction of early and late apoptosis along with inducing sub-G1 cell cycle arrest in a dose-dependent manner. Papaverine induced a dose-dependent reduction in the expression levels of Blc-2 proteins and a dose-dependent increase in the expression levels of Bax protein. The expression levels of NF-kB were decreased markedly in comparison to the untreated control. Papaverine treatment also led to a dose-dependent downregulation of PI3K and phospho-Akt expression.
Conclusion: Papaverine showed selective antitumor properties against PC-3 human prostate cancer cells by inducing early and late apoptosis, sub-G1 cell cycle arrest, modulation of apoptosis-related proteins like Bcl-2, Bax, Bid, XIAP and cytochrome C along with downregulation of NFkB, PI3K/Akt signalling pathway.