HeLa Cell Apoptosis Induced by Quercetin and Effects of Caspase-3,Caspase-8 Activation on Apoptosis

OBJECTIVE To study the apoptosis of HeLa cells(human cervical cancer cells) induced by quercetin and the effects of caspase-3,caspase-8 activation on the apoptosis.METHODS Colorimetric MTT assay was used to measure the inhibition of quercetin in HeLa cells and L-02 cells.The morphological changes of HeLa cells were observed by fluorescence microscope after DAPI staining.The apoptosis of treated cells were examined by DNA agarose gel electrophoresis analysis of DNA fragmentation and flow cytometry using fluorescein labeling FITC-Annexin V/PI,respectively.The activity of caspase-3 and caspase-8 in apoptosis as detected by colorimetric assay.RESULTS MTT results showed that quercetin could inhibit the growth of HeLa cells in dose-and time-dependent manner significantly,but couldn't inhibit the growth of L-02 cells(P0.05).The phenomenon of nuclear condensation and marginalization by DAPI staining and the characteristic bands of apoptosis by DNA electrophoresis were found in HeLa cells treated with quercetin at 160.0 μmol·L-1for 72 h.The rates of apoptosis of HeLa cells which were treated with quercetin at 160.0 μmol·L-1for 24,48 and 72 h were(9.4±2.1)%、(30.1±6.5)% and(59.8±9.5)%,respectively.The maximal activities of intracellular caspase-3 at 48 h and caspazse-8 at 24 h were(1.68±0.07) and(1.83±0.06)U·μg-1,respectively.There was significantly difference compared with the control group(P0.05).CONCLUSION Quercetin can specifically induce the apoptosis of HeLa cells,and intracellular caspase-3 and caspase-8 are closely associated with the apoptosis.