Papaverine selectively inhibits human prostate cancer cell (PC-3) growth by inducing mitochondrial mediated apoptosis, cell cycle arrest and downregulation of NF-κB/PI3K/Akt signalling pathway.

Abstract 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. 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. 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. 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.