Quercetin Induces Mitochondrial Mediated Apoptosis and Protective Autophagy in Human Glioblastoma U373MG Cells
Quercetin inhibits cell growth and induces apoptosis. (a) Cell viability was determined by MTT reduction. U373MG human glioblastoma cells were treated with increasing doses of quercetin for different lengths of time (24–72 h). Data are the mean ± standard error for one experiment performed in triplicate. Values are the mean ± standard deviation (SD) of three independent experiments. compared to the control. (b) Treated cells were stained with nuclear Hoechst 33342 and visualized under a fluorescence microscope after a 48 h treatment. White arrows indicate apoptotic bodies. Representative areas were photographed with 200X magnification. (c) Graph for quantification of number of apoptotic bodies. Data are the mean ± standard error for one experiment performed in triplicate. compared to the control. (d) Flow cytometry analysis of JC-1 staining. Cells were trypsinized, stained with JC-1, washed, and analyzed by flow cytometry. The decrease in mitochondrial membrane potential percentage indicates that cells were undergoing mitochondrial dysfunction. (e) Caspase-9 and (f) caspase-3 activities in U373MG cells. Caspase activities were measured by a colorimetric assay and calculated as fold changes compared to the same control. The cells were treated with quercetin for 48 h ((b)–(f)). All data are the mean ± SD of three independent experiments. a: significantly different from the control, .