[Effects of gambogic acid on the regulation of steroid receptor coactivator-3 in A549 cells].

OBJECTIVE

To investigate the effects of gambogic acid (GA) on the proliferation inhibition and apoptosis induction in Human lung adenocarcinoma A549 cells in vitro, as well as the regulation of steroid receptor coactivator-3 (SRC-3) to explore the relationship between them.

METHODS

The effect of GA on the growth of A549 cells was studied by MTT assay. Apoptosis was detected by Hoechst 33258 staining. The localization of SRC-3 was determined by confocal laser scanning microscopy. Western blot and RT-PCR technique were applied to assess the expression of SRC-3.

RESULTS

GA presented a striking proliferation inhibition potency on A549 cells in vitro, as well as apoptosis induction activity in a time- and dose-dependent manner. The IC(50) value for 24 h was (3.17 +/- 0.13) micromol/L. Overexpression of SRC-3 was found in A549 cells, whereas the SRC-3 protein and mRNA expression levels were significantly downregulated in A549 cells induced by GA in a dose-dependent manner. The location of SRC-3 was situated mainly in the cell nuclei.

CONCLUSION

GA exhibits a potent proliferation inhibition and apoptosis induction in human lung adenocarcinoma A549 cells, which might correspond to the downregulation of the expression of SRC-3. Thus, it promises to be a new target drug for lung cancer treatment.