title: Wentilactone B induces G2/M phase arrest and apoptosis via the Ras/Raf/MAPK signaling pathway in human hepatoma SMMC-7721 cells.
abstract: Hepatocellular carcinoma (HCC) is generally acknowledged as the most common primary malignant tumor, and it is known to be resistant to conventional chemotherapy. Wentilactone B (WB), a tetranorditerpenoid derivative extracted from the marine algae-derived endophytic fungus Aspergillus wentii EN-48, has been shown to trigger apoptosis and inhibit metastasis in HCC cell lines. However, the mechanisms of its antitumor activity remain to be elucidated. We report here that WB could significantly induce cell cycle arrest at G2 phase and mitochondrial-related apoptosis, accompanying the accumulation of reactive oxygen species (ROS). Additionally, treatment with WB induced phosphorylation of extracellular signal-regulated kinase (ERK), c-Jun N-terminal kinase (JNK), but not p38 MAP kinase. Among the pathway inhibitors examined, only SP600125 (JNK inhibitor) markedly reversedWB-induced apoptosis, and only U0126 (ERK inhibitor) significantly blocked WB-triggered G2 phase arrest. We also found that WB treatment increased both Ras and Raf activation, and transfection of cells with dominant-negative Ras (RasN17) abolishedWB-induced apoptosis and G2 phase arrest in SMMC-7721 cells. Furthermore, the results of inverse docking (INVDOCK) analysis suggested that WB could bind to Ras-GTP, and the direct binding affinity was also confirmed by surface plasmon resonance (SPR). Finally, in vivo, WB suppressed tumor growth in mouse xenograft models. Taken together, these results indicate that WB induced G2/M phase arrest and apoptosis in human hepatoma SMMC-7721 cells via the Ras/Raf/ERK and Ras/Raf/JNK signaling pathways, and this agent may be a potentially useful compound for developing anticancer agents for HCC.
authors.affiliation: Department of Biochemistry and Molecular Biology, Faculty of Basic Medicine, Second Military Medical University, Shanghai, China.
authors.forename: Z
authors.initials: Z
authors.lastname: Zhang
authors.forename: L
authors.initials: L
authors.lastname: Miao
authors.forename: C
authors.initials: C
authors.lastname: Lv
authors.forename: H
authors.initials: H
authors.lastname: Sun
authors.forename: S
authors.initials: S
authors.lastname: Wei
authors.forename: B
authors.initials: B
authors.lastname: Wang
authors.forename: C
authors.initials: C
authors.lastname: Huang
authors.forename: B
authors.initials: B
authors.lastname: Jiao
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D004789:Enzyme Activation; D005472:Fluorouracil / Q000494:pharmacology; D059565:G2 Phase Cell Cycle Checkpoints / Q000187:drug effects*; D015870:Gene Expression / Q000187:drug effects; D056945:Hep G2 Cells; D006576:Heterocyclic Compounds, 4 or More Rings / Q000494:pharmacology*; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy*; D020935:MAP Kinase Signaling System; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D051379:Mice; D008819:Mice, Nude; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D011485:Protein Binding; D017382:Reactive Oxygen Species / Q000378:metabolism; D023041:Xenograft Model Antitumor Assays; D048490:raf Kinases / Q000378:metabolism; D018631:ras Proteins / Q000378:metabolism
chemical_list: D000970:Antineoplastic Agents; D018797:Cell Cycle Proteins; D006576:Heterocyclic Compounds, 4 or More Rings; D017382:Reactive Oxygen Species; C454809:wentilactone B; D048490:raf Kinases; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins; D005472:Fluorouracil