Extract From Yellow Passion‐Fruit (passilora edulis) Inhibits Prostate Cancer Cell Proliferation By TLR4/NFkB Pathway Regulation

Abstract

The yellow passion‐fruit (passiflora‐edulis) is rich in piceatannol (PIC), a polyphenolic and resveratrol analog known by its beneficial effects on health such as anti‐inflammatory anti‐cancer properties. The present study aimed to investigate the passion‐fruit extract (PFE) mechanistic of action in prostate cancer (PCa) cell lines with different genetic backgrounds and in the transgenic adenocarcinoma of the mouse prostate (TRAMP). For in vitro experiments, LNCaP (androgen‐responsive) and PC‐3 (androgen‐independent) cells were treated with different doses of PFE (125–500 μg/mL) and used for cell viability assay and western blotting analysis. For in vivo experiments, TRAMP mice were gavaged with 20mg/Kg of PIC contained in the PFE during 4 or 10 weeks of treatment. The ventral prostate was collected for light microscopy, immunohistochemistry and western blotting analysis. Because inflammation is intrinsically evolved with prostate alterations, like hormonal imbalance and cell survival, we focused on if PFE could affect these pathways. PFE treatment caused a significant reduction of cell viability in both cell lines tested, as well as decreased nuclear factor kappa B (NFκB) and toll‐like receptor 4 protein level. Interestingly, LNCaP cells were more sensitive to the PFE action in all experiments and we verified that the androgen receptor was markedly reduced by the treatment in these cells. PFE delayed CaP progression in the TRAMP model in both periods of treatment, significantly decreasing high‐grade prostatic intraepithelial neoplasia and well‐differentiated adenocarcinoma. These results were confirmed by the decrease of proliferating cell nuclear antigen immunostaining. Also, treatment with PFE reduced inflammation markers such as tumor necrosis factor‐alpha (TNF‐α), NFκB, and modulated negatively cell cycle regulatory protein levels and signal transducer and activator of transcription 3. Therefore, the results herewith showed that PFE was able to modulate disease progression through the inhibition of the inflammatory pathways, delay of the cell cycle, especially in the hormone‐dependent profile, demonstrating its chemopreventive and therapeutic potential in PCa. Support or Funding Information Sao Paulo Research Foundation ( Number: 2017/01573‐5)