Oleanolic acid-induced apoptosis and its relation with intracellular calcium in human lung adenocarcinoma A549 cells / 西安交通大学学报·英文版

ABSTRACT

Objective: To investigate the effect of oleanolic acid (OA) on apoptosis, correlation between apoptosis and intracellular calcium, and its mechanism in human lung adenocarcinoma cell line A549. Methods: Human lung adenocarcinoma A549 cells were incubated in vitro and assigned with OA concentrations of 0, 10, 20 and 40 μg/mL. The apoptosis status of A549 cell line was detected with Annexin V-FITC/PI by flow cytometry (FCM) ; fluorescence intensity (FI) of A549 cells was assessed and the level of intracellular calcium was calculated at 24 hour of OA intervention. The relation between apoptosis and calcium FI was illustrated by curve fitting. Results: FCM showed that 10, 20 and 40 μg/mL of OA could induce A549 cell apoptosis, which followed a concentration-effect pattern; 24-hour intervention with 20 μg/mL and 40 μg/mL OA showed increased A549 cell apoptosis, and was significantly different from that with 0 μg/mL OA (P<0.01). The FI of intracellular calcium concentration in 10, 20 and 40 μg/mL OA groups was significantly higher than that in 0 μg/mL group after 24 hours' intervention, and the FI showed a trend of increase with increased OA concentration (P<0.01). Curve fitting showed a significant correlation between apoptosis rate and intracellular calcium concentration in A549 cells (r=0.981, P<0.01). Regression equation was Y = 0.508X-1.627. Conclusion: OA plays a role in inducing apoptosis of human lung adenocarcinoma cells in a concentration-dependent manner. The OA-induced apoptosis is responsible for intracellular calcium overload of the tumor.