Effect of quercetin on the biological characteristics of human glioma U251 cells

Abstract

Objectives To Study the effect of quercetin on the biological characteristics of human glioma U251 cells and to investigate its possible mechanisms. Methods The U251 cells were cultured in vitro. The effect of quercetin on the proliferation of U251 cells was detected by CCK8 assay. Flow cytometry was used to detect the effect of quercetin on the U251 cell cycle and apoptosis. Scratch test and Transwell test were used to observe the effect of quercetin on metastasis and invasion of U251 cells. Western blot was used to detect the effects of quercetin on protein expression levels of U251 cell Bax, Bcl-2, MMP-9, and MMP-2. Results Quercetin could inhibit the proliferation ability in vitro of U251 cells. IC50 at 24 h and 48 h were 113.65 μg/ml and 48.61 μg/ml respectively. Flow cytometry showed that quercetin acting on U251 cells might have some changes, such as the upregulation of peak ratio, the downregulation of G0/G1 phase rate, and upregulation of G2/M phase rate. The migration and invasion abilities of the U251 cells pretreated by quercetin for 24 h were decreased significantly compared with the control group, and the 20 μg/ml group was lower than the10 μg/ml group (P<0.05). After the U251 cells being treated with quercetin, the Bax expression level was upregulated, the Bcl-2, MMP-9, and MMP-2 protein expression levels were decreased, and there was significant difference between the 10 μg/ml group and the 20 μg/ml group (P<0.05). Conclusions Quercetin has significant cytotoxic effect in vitro on U251 cells. It can induce apoptosis of U251 cells, causing G2/M phase arrest, decreasing the cell migration and invasion abilities. These effects may be associated with the decrease of Bcl-2/Bax ratio and the downregulation of MMP-9 and MMP-2 protein expression levels. Key words: Glioma; Quercetin; Apoptosis; Cell migration assays; Neoplasm invasiveness