RESUMO
<p><b>OBJECTIVE</b>To study the in-vitro inducing apoptosis mechanism of human hepatoma SMMC-7721 cells by 2',4'-di- hydroxy-6'-methoxy-3',5'-dimethylchalcone (DMC), a chalcone compound from Cleistocalyx operculatus.</p><p><b>METHOD</b>Quantitative DNA fragmentation assay was carried out to detect the effect of DMC of different concentrations on SMMC-7721 cells, according to the method of Sellins and Cohen with some modifications. Telomerase activities of the cells were determined by PCR-ELISA methods. The expression quantity of c-myc and hTERT mRNA were determined by semi-quantitative RT-PCR The effect of DMC on expression levels of cmyc and hTERT protein were measured by western blot.</p><p><b>RESULT</b>The percentage of DNA fragmentation increased with notable concen- tration dependence, after treatment with DMC for 48 h. Compared with that of control group, the telomerase activity of the cells de- creased by (66.2 ± 2.1)% after 48 h treatment with 20 μmol x L(-1) DMC, the mRNA expression of c-myc and hTERT decreased by (67.3 ± 2.1)% and (64.4 ± 2.3)%, respectively, and the protein expression of c-myc and hTERT decreased by (69.6 ± 1.9)% and (71.3 ± 2.4)%, respectively.</p><p><b>CONCLUSION</b>DMC can induce SMMC-7721 cell apoptosis and the apoptosis mechanism may be related to the decreased mRNA and protein expression of c-myc and hTERT.</p>