The critical role of quercetin in autophagy and apoptosis in HeLa cells

Abstract

In recent years, the effects of quercetin on autophagy and apoptosis of cancer cells have been widely reported, while effects on HeLa cells are still unclear. Here, HeLa cells were subjected to quercetin treatment, and then proliferation, apoptosis, and autophagy were evaluated using MTT, flow cytometry, and MDC staining, respectively. The LC3-I/II, Beclin 1, active caspase-3, and S6K1 phosphorylation were detected using Western blot assay. The ultrastructure of HeLa was observed via transmission electron microscope (TEM). Our findings showed that quercetin can dose-dependently inhibit the growth of HeLa cells. The MDC fluorescence was enhanced with increased concentration of quercetin and hit a plateau at 50 μmol/l. Western blot assay revealed that LC3-I/II ratio, Beclin 1, and active caspase-3 protein were enforced in a dose-dependent method. However, the phosphorylation of S6K1 gradually decreased, concomitant with an increase of autophagy. In addition, TEM revealed that the number of autophagic vacuoles was peaked at 50 μmol/l of quercetin. Besides, interference of autophagy with 3-MA led to proliferation inhibition and increased apoptosis in HeLa cells, accompanied by the decreased LC3-I/II conversion and the increased active caspase-3. In conclusion, quercetin can inhibit HeLa cell proliferation and induce protective autophagy at low concentrations; thus, 3-MA plus quercetin would suppress autophagy and effectively increased apoptosis.

Ameliorative Effect of Quercetin on Neurochemical and Behavioral Deficits in Rotenone Rat Model of Parkinson's Disease: Modulating Autophagy (Quercetin on Experimental Parkinson's Disease)

“…The current study revealed decreased Beclin‐1 level in rotenone‐treated group indicating suppression of autophagy as previously observed , whereas quercetin co‐treatment increased it, suggesting induction of autophagy which came in line with previous reports demonstrating that quercetin upregulated Beclin‐1 expression .…”

Quercetin Inhibits Inflammasome Activation by Interfering with ASC Oligomerization and Prevents Interleukin-1 Mediated Mouse Vasculitis

“…It has been reported that quercetin can induce autophagy in gastric cancer cells and HeLa cells 24 25 . Autophagy is the process by which cellular components can be recycled, either as a normal process or to remove damaged organelles 26 .…”

The Flavonoid Quercetin Protects MDCK Cells against Toxicity of CPT by Induction of Autophagy

“…Wortmannin negates the protective effect of quercetin, indicating that the protection operates through the increase in autophagy, as we know that autophagy induced by several means including by rapamycin can protect cells against CPT [19]. Quercetin induces protective autophagy in gastric cancer cells and HeLa cells, while disruption of autophagy by genetic knockout or blockage of autophagy by 3-methyladenine or chloroquine induced apoptosis in these cells [39,40]. Quercetin also induces autophagy through ER stress in ovarian cancer cells [41].…”