Luteolin Induces Apoptosis and Autophagy in Mouse Macrophage ANA-1 Cells via the Bcl-2 Pathway

Plants rich in luteolin have been used as Chinese traditional medicines for inflammatory diseases, hypertension, and cancer. However, little is known about the effect of luteolin on the apoptosis or autophagy of the macrophages. In this study, mouse macrophage ANA-1 cells were incubated with different concentrations of luteolin. The viability of the cells was determined by an MTT assay, apoptosis was determined by flow cytometric analysis, the level of cell autophagy was observed by confocal microscopy, and the expression levels of apoptotic or autophagic and antiapoptotic or antiautophagic proteins were detected by Western blot analysis. The results showed that luteolin decreased the viability of ANA-1 cells and induced apoptosis and autophagy. Luteolin induced apoptosis accompanied by downregulation of the expression of Bcl-2 and upregulation of the expression of caspase 3 and caspase 8. And luteolin increased FITC-LC3 punctate fluorescence accompanied by the increased expression levels of LC3-I, ATG7, and ATG12, while it suppressed the expression level of Beclin-1. Luteolin treatment resulted in obvious activation of the p38, JNK, and Akt signaling pathways, which is important in modulating apoptosis and autophagy. Thus, we concluded that luteolin induced the apoptosis and autophagy of ANA-1 cells most likely by regulating the p38, JNK, and Akt pathways, inhibiting the activity of Bcl-2 and Beclin-1 and upregulating caspase 3 and caspase 8 expression. These results provide novel insights into a therapeutic strategy to prevent and possibly treat macrophage-related diseases through luteolin-induced apoptosis and autophagy.