Platycodin D triggers autophagy through activation of extracellular signal-regulated kinase in hepatocellular carcinoma HepG2 cells

摘要: Platycodin D (PD), isolated from the Chinese medicinal herb named Platycodonis Radix, is a triterpenoid saponin with well-known anti-tumor effects. In this study, we provided reliable evidence that PD triggered autophagy in number of cell lines vitro. PD-triggered was identified by observation cytoplasmic vacuole, up-regulation microtubule-associated protein 1 light chain 3 II (LC3-II), and accumulation autophagosomes. The Akt/mammalian target rapamycin (mTOR) pathway may be not involved autophagy, as evidenced increased phosphorylation Akt (Thr308), mTOR (Ser2448), ribosomal S6 kinase (Ser371), ULK1 (Ser757). However, extracellular signal-regulated (ERK) activated after treatment. decreased ERK caused pretreatment U0126, an inhibitor MEK, suppressed expression LC3-II compared treatment alone, suggesting have critical function autophagy. addition, PD-induced proliferative inhibition apoptosis were enhanced when chloroquine (CQ) or bafilomycin A1 (BAF), indicating trigger protective HepG2 cells. To best our knowledge, paper first to report triggers series activation important for hepatocellular carcinoma combined CQ BAF promising regimen