Scutellarin suppresses proliferation and promotes apoptosis in A549 lung adenocarcinoma cells via AKT/mTOR/4EBP1 and STAT3 pathways

Background Scutellarin (SCU), a flavonoid isolated from Erigeron breviscapus (Vant.) Hand.-Mazz., increases autophagy and apoptosis in the adenocarcinoma A549 cell line, which is resistant to cisplatin. However, whether SCU alone has antitumor activity against non-small cell lung cancer (NSCLC) is unknown. Methods Cell Counting Kit-8, flow cytometry, colony formation, Hoechst 33258 staining, and Western blot analyses were used to examine the proliferation and apoptosis of A549 cells treated with SCU and the possible molecular mechanisms. Results The cell viability assay indicated that SCU markedly suppressed the proliferation of A549 cells in concentration and time-dependent manners. SCU caused significant G0/G1 phase arrest and apoptosis, as evidenced by flow cytometric analyses, Hoechst 33258 staining, and Western blot analyses of cyclin D1, cyclin E, BCL-2, cleaved-caspase-3, and BAX. Furthermore, SCU treatment reduced the level of pan-AKT, phosphorylated (p)-mTOR, mTOR, BCL-XL, STAT3, and p-STAT3, and increased the level of 4EBP1. Conclusions SCU can suppress proliferation and promote apoptosis in A549 cells through AKT/mTOR/4EBP1 and STAT3 pathways. This suggests that SCU may be developed into a promising antitumor agent for treating NSCLC.