title: Suppression of vascular endothelial growth factor via inactivation of eukaryotic elongation factor 2 by alkaloids in Coptidis rhizome in hepatocellular carcinoma.
abstract: OBJECTIVE
  To investigate the inhibitory effect of Coptidis rhizome aqueous extract (CRAE) on vascular endothelial growth factor (VEGF) expression and tumor angiogenesis in hepatocellular carcinoma (HCC).
  
  
  METHODS
  Quality control of CRAE was determined. Secretion of VEGF protein and expression of its mRNA in MHCC97L and Hep G2 cells were measured with enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction. Synthesis of nascent protein was determined by AHA-protein-labeling technologies. The in vivo antiangiogenic effect of CRAE was evaluated with a xenograft model.
  
  
  RESULTS
  Absence of organochlorine pesticides in CRAE was found, and phytochemical analysis showed that its components were in proportion of magnoflorine 2.2%, jatrorrhizine 1.68%, palmatine 4.4%, and berberine 13.8%. CRAE exhibited significant inhibition on VEGF secretion from MHCC97L and HepG2 cells at nontoxic doses. The mRNA transcripts of VEGF could not be inhibited by CRAE; however, synthesis of VEGF nascent protein was potently blocked by CRAE. CRAE intervention increased the phosphorylation of eukaryotic elongation factor 2 (eEF2) in HCC cells, which blocked eEF2 activity for proceeding nascent protein synthesis. The activity of eEF2 was restored in CRAE-treated HCC cells in the presence of A484594, leading to the recovery of VEGF expression. Berberine was found to be the major active component in CRAE; however, CRAE is more effective in inhibiting eEF2 activity compared to berberine treatment alone, suggesting the additive effect of other components present. Reduction of tumor size and neovascularization were observed in mice xenograft model.
  
  
  CONCLUSIONS
  Our study postulates the antiangiogenic effect of CRAE on hepatocellular carcinoma via an eEF2-driven pathway.
authors.affiliation: School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Hor Yue
authors.initials: HY
authors.lastname: Tan
authors.affiliation: School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Wang
authors.affiliation: Department of Anatomy, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Sai-Wah
authors.initials: SW
authors.lastname: Tsao
authors.affiliation: School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China.
authors.forename: Zhangjin
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: School of Chinese Medicine, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong SAR, China yfeng@hku.hk.
authors.forename: Yibin
authors.initials: Y
authors.lastname: Feng
mesh_terms: D000470:Alkaloids / Q000302:isolation & purification / Q000494:pharmacology*; D020533:Angiogenesis Inhibitors / Q000302:isolation & purification / Q000494:pharmacology; D000818:Animals; D006528:Carcinoma, Hepatocellular / Q000188:drug therapy* / Q000473:pathology; D045744:Cell Line, Tumor; D000089042:Coptis chinensis; D004365:Drugs, Chinese Herbal / Q000737:chemistry*; D004797:Enzyme-Linked Immunosorbent Assay; D015972:Gene Expression Regulation, Neoplastic; D056945:Hep G2 Cells; D006801:Humans; D008113:Liver Neoplasms / Q000188:drug therapy* / Q000473:pathology; D051379:Mice; D008819:Mice, Nude; D009389:Neovascularization, Pathologic / Q000188:drug therapy / Q000473:pathology; D020652:Peptide Elongation Factor 2 / Q000187:drug effects; D060888:Real-Time Polymerase Chain Reaction; D042461:Vascular Endothelial Growth Factor A / Q000037:antagonists & inhibitors / Q000235:genetics; D023041:Xenograft Model Antitumor Assays
chemical_list: D000470:Alkaloids; D020533:Angiogenesis Inhibitors; D004365:Drugs, Chinese Herbal; D020652:Peptide Elongation Factor 2; D042461:Vascular Endothelial Growth Factor A; C107393:Coptidis rhizoma extract
keywords: Coptidis rhizome aqueous extract; eukaryotic elongation factor 2; hepatocellular carcinoma; nascent protein synthesis; vascular endothelial growth factor