Suppression of APC production during apoptosis of human colorectal cancer cell line SW480 induced by gambogic acid

Objective To investigate the effect of gambogic acid on human colorectal cancer cell line SW480. Methods Methyl thiazolyl tetrazolium (MTT) assay was used to test the changes in the proliferation of SW480 cells cultured with different concentrations of gambogic acid for 24, 36 and 48 h in vitro. Cell-cycle kinetics and apoptosis were analyzed by flow cytometry (FCM). Western-blot was applied to examine the protein expression of APC. Results Gambogic acid with concentration greater than 1 μg/ml could significantly inhibit the proliferation of human colorectal cancer cell line SW480 and the effect was more prominent as time went on (P0.01). The G2/M phase cells reached 54.74% with gambogic acid at concentration of 4 μg/ml. When SW480 cells were treated with gambogic acid at the concentration of 0, 0.5, 1 and 4 μg/ml, the rate of apoptosis of SW480 cell were (0.17±0.08)%, (0.85±0.19)%, (7.12±1.21)%, and (15.87±1.59)%, respectively. After SW480 cells were treated with 0, 0.5, 1 and 4 μg/ml gambogic acid for 24 h respectively, the level of APC protein increased as concentration increased (P0.01). Conclusion Gambogic acid can significantly inhibit the proliferation and induces G2/M arrest in human colon cancer cell line SW480. The effect mechanism is related to the suppression of APC protein production.