Apoptosis of Human Lung Adenocarcinoma A549 Cells Induced by Aloe Polysaccharide Through the Mitochondrial Pathway

OBJECTIVE To investigate the induction effect of aloe polysaccharide (AP) on lung adenocarcinoma cells line A549 and to explore corresponding mechanism. METHODS After treatment of AP on A549 cells, MTS method was used to measure the growth curve of the cells so as to observe the effect of the AP on the proliferation of A549 cells, and the apoptosis of A549 cells were detected by Hoechst staining and DNA ladder electrophoresis. The expression of caspase-9, caspase-8 and caspase-3 was examined by Western blot and the enzyme activity of these caspases was examined by using a colorimetric method. RESULTS AP could inhibit proliferative activity of A549 cells in a time-dependent and dose-dependent manner(P<0.01). AP could promote DNA non-random cut morphological changes and chromatin condensation and nuclear fragmentation of apoptosis in a time-dependent manner in A549 cells(P<0.01). The activation of caspase-9, caspase-8 and caspase-3 of A549 cells induced by AP was observed within 24 h, and the activation of caspase-9 and caspase-3 was earlier than that of caspase-8. Expression of Bcl-2 was down-regulated in a time-dependent manner. CONCLUSION AP can inhibit the growth and induce apoptosis of human lung adenocarcinoma A549 cells, the mechanism is associated with activation of the mitochondrial apoptotic pathway.