Effects of quercetin on proliferation of lung cancer cell line A549 by down-regulating hTERT gene expression
WANG Jian,ZHANG Peng-hui,TU Zhi-guang (Faculty of Laboratory Medicine,Chongqing Medical University,Chongqing 400016,China)
Objective To investigate the effects of quercetin on the growth of lung cancer cell line A549 and the expression of hTERT gene. Methods The number of viable cells was ascertained by trypan blue dye exclusion test. Morphological changes of apoptotic cells were observed by electronic microscopy and DNA ladder assay. The telomerase activity was analyzed by PCR-TRAP assay and hTERT mRNA expression was detected by quantitative RT-PCR. Results Quercetin had a significant inhibition on the proliferation of A549 cells in a dose-dependent manner. The IC50 was 22.5 μmol/L after exposure to quercetin for 48 h. The results from electron microscopy and DNA ladder showed that apoptosis occurred in the A549 cells of treatment groups. The results of quantitative RT-PCR and PCR-TRAP revealed that the expression of hTERT mRNA was significantly inhibited by quercetin and telomerase activity was decreased. Conclusion Quercetin inhibits the growth of lung cancer cell line A549 in a dose-dependent manner,and induce their apoptosis. The down-regulated expression of hTERT,suppression of telomerase activity and destruction of telomere stability may all contribute to the mechanism of apoptosis induction.