title: Autophagy is induced by 3β-O-succinyl-lupeol (LD9-4) in A549 cells via up-regulation of Beclin 1 and down-regulation mTOR pathway.
abstract: The purpose of this study is to investigate the antitumor activity of a new derivative of lupeol-3β-O-succinyl-lupeol (LD9-4) and the molecular mechanism underlying cell death in human non-small cell lung cancer A549 cells. The results revealed that LD9-4 inhibited A549 cell proliferation in a time- and dose-dependent manner, with an IC(50) value of 5.78 ± 0.48 μM after cells exposed to LD9-4 for 72 h. Markers indicative of apoptosis (cell cycle arrest, phosphatidylserine externalization and Hoechst33258 staining) were uniformly negative in LD9-4 exposed cells. Interestingly, transmission electron microscope, MDC staining and LC3 level determination all confirmed that autophagy was induced in LD9-4 treated A549 cells. Furthermore, we found that LD9-4-induced autophagy in A549 cells was associated with the increase of intracellular reactive oxygen species and the decrease of phosphorylated mTOR and p70S6K levels. In the meanwhile, both mRNA and protein levels of Beclin 1 were up-regulated in a time-dependent manner. Our data suggest that autophagy is induced by LD9-4 in A549 cells, and the accumulating reactive oxygen species, up-regulation of Beclin 1 and inhibition of the mTOR signaling pathway are involved in this process.
authors.affiliation: Key Laboratory of Plant Resources Conservation and Sustainable Utilization, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou, 510650, PR China.
authors.forename: Jing
authors.initials: J
authors.lastname: Hao
authors.forename: Ying
authors.initials: Y
authors.lastname: Pei
authors.forename: Guiyuan
authors.initials: G
authors.lastname: Ji
authors.forename: Weijie
authors.initials: W
authors.lastname: Li
authors.forename: Shixiu
authors.initials: S
authors.lastname: Feng
authors.forename: Shengxiang
authors.initials: S
authors.lastname: Qiu
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D017209:Apoptosis / Q000187:drug effects; D051017:Apoptosis Regulatory Proteins / Q000235:genetics* / Q000378:metabolism*; D001343:Autophagy / Q000187:drug effects*; D000071186:Beclin-1; D045744:Cell Line, Tumor; D006801:Humans; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D020782:Matrix Metalloproteinases / Q000378:metabolism; D008565:Membrane Proteins / Q000235:genetics* / Q000378:metabolism*; D009336:Necrosis / Q000139:chemically induced; D053978:Pentacyclic Triterpenes / Q000494:pharmacology*; D017382:Reactive Oxygen Species / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects*; D013386:Succinates / Q000494:pharmacology*; D058570:TOR Serine-Threonine Kinases / Q000378:metabolism*; D015854:Up-Regulation / Q000187:drug effects*; D000094042:Lupanes
chemical_list: D000970:Antineoplastic Agents; D051017:Apoptosis Regulatory Proteins; D000071186:Beclin-1; D020782:Matrix Metalloproteinases; D008565:Membrane Proteins; D053978:Pentacyclic Triterpenes; D017382:Reactive Oxygen Species; D013386:Succinates; D058570:TOR Serine-Threonine Kinases; C569747:3-O-succinyl-lupeol; D000094042:Lupanes; C491997:BECN1 protein, human; C010480:lupeol