Quercetin-mediated apoptosis and cellular senescence in human colon cancer

Abstract

Background: Quercetin is a flavonol from the flavonoid group of polyphenols, which positively affects human health due to its anti-cancer, anti-inflammatory, anti-microbial and cardioprotective effects. The effects of phenolic compounds, including quercetin, on programmed cell death and cellular senescence, have been the subject of research in recent years. Objective: In this study, we aimed to investigate the effects of quercetin on cell viability, apoptosis and cellular senescence in primary (Colo-320) and metastatic (Colo-741) colon adenocarcinoma cell lines. Methods: Cytotoxicity was analyzed via MTT assay in Colo-320 and Colo-741 cell lines. After quercetin treatment, cell ularsenescence and apoptosis were evaluated by TUNEL staining, X-Gal staining and indirect peroxidase tech-nique for immunocytochemical analysis of related proteins such as Bax, Bcl-2, caspase-3, Hsp27, Lamin B1, p16, cyclin B1. Results: The effective dose for inhibition of cell growth in both cell lines was determined to be 25µg/ml quercetin for 48 hours. Increased Baximmunoreactivityfollowingquercetin treatment was significant in both Colo-320 and Colo-741 cell lines, but decreased Bcl-2 immunoreactivitywas significant only in theColo-320 primary cell line. In addition, after quercetin administration, the number of TUNEL positive cells and, immunoreactivities for p16, Lamin B1 and cyclin B1 in both Colo-320 and Colo-741 cells increased. Conclusion: Our results suggest that quercetin may only induce apoptosis in primary colon cancer cells. Further-more, quercetin also triggered senescence in colon cancer cells, but some cells remained alive, suggesting that colon cancer cells might have escaped from senescence. © 2020 Bentham Science Publishers.