K[sub.5]BW[sub.12]O[sub.40] Induces the Apoptosis of A549 Cells by Regulating Caspase-3

Objective. The purpose of the study is to explore the effect of K[sub.5]BW[sub.12]O[sub.40,] a polyoxometalate (POM), on the apoptosis of A549 cells and its underlying mechanism and to analyze the potential therapeutic effect of K[sub.5]BW[sub.12]O[sub.40] in non-small-cell lung cancer. Materials and Methods. A549 cells were treated with different concentrations of K[sub.5]BW[sub.12]O[sub.40] (0mg/ml, 0.001mg/ml, 0.01mg/ml, and 0.1mg/ml). The proliferation of A549 cells treated with different concentrations of K[sub.5]BW[sub.12]O[sub.40] was detected by MTT assay (3-(4,5-dimethylthiazol-2-yl)-2 and 5-diphenyl tetrazolium bromide). The apoptosis of A549 cells induced by K[sub.5]BW[sub.12]O[sub.40] was detected by flow cytometry. Western blot was used to detect the changes in Bax and caspase-3 protein levels in A549 cells induced by K[sub.5]BW[sub.12]O[sub.40]. Results. As the dose of the K[sub.5]BW[sub.12]O[sub.40] increases, the cell viability of A549 cells gradually decreases. The results of flow cytometry showed that the apoptotic rate of A549 cells increased with the increase of K[sub.5]BW[sub.12]O[sub.40] concentration. Western blot results showed that the expression of the apoptosis marker protein caspase-3 was increased in the three groups treated with K[sub.5]BW[sub.12]O[sub.40] whereas the protein level of Bax did not change significantly in A549 cells treated with K[sub.5]BW[sub.12]O[sub.40]. Conclusions. K[sub.5]BW[sub.12]O[sub.40] increases the apoptotic rate of A549 cells by upregulating caspase-3.