Pumpkin Seed Extracts Inhibit Proliferation and Induce Autophagy in PC-3 Androgen Insensitive Prostate Cancer Cells

Pumpkin seed is a rich source of polyphenols and other bioactive compounds that may act as chemopreventive agents against cancer. In this study, five different extracts of pumpkin seeds were evaluated for their ability to affect proliferation and autophagy on PC-3 prostate cancer cells. All extracts (water [W], methanolic, acetone, ethylacetate, and polar lipid [PL]) inhibited cell proliferation in a dose-dependent manner. Treatment of cells with the PL extract increased cell distribution in the S phase, whereas PL and W extracts induced autophagy significantly. Moreover, PL extract induced a remarkable increase of glutathione and oxidized glutathione levels, whereas nitrite and hydrogen peroxide levels were not altered. In conclusion, pumpkin seed extracts affect PC-3 cell viability, oxidative parameters, and autophagic mechanism, thus demonstrating their potential pharmacological use.