title: Involvement of hypoxia-inducing factor-1alpha-dependent plasminogen activator inhibitor-1 up-regulation in Cyr61/CCN1-induced gastric cancer cell invasion.
abstract: Cysteine-rich 61 (Cyr61/CCN1), one of the members of CCN family, has been implicated in the progression of human malignancies. Previously, our studies have demonstrated that Cyr61/CCN1 has a role in promoting gastric cancer cell invasion, but the mechanism is not clear yet. Here, we found that hypoxia-inducing factor-1alpha (HIF-1alpha) protein, but not mRNA, expression was significantly elevated in gastric cancer cells overexpressing Cyr61. Supportively, a profound reduction of endogenous HIF-1alpha protein was noted in one highly invasive cell line, TSGH, when transfected with antisense Cyr61. By comparison, the induction kinetics of HIF-1alpha protein by recombinant Cyr61 (rCyr61) was distinct from that of insulin-like growth factor-1 and CoCl(2) treatment, both well known for induction of HIF-1alpha. Using cycloheximide and MG132, we demonstrated that the Cyr61-mediated HIF-1alpha up-regulation was through de novo protein synthesis, rather than increased protein stability. rCyr61 could also activate the PI3K/AKT/mTOR and ERK1/2 signaling pathways, both of which were essential for HIF-1alpha protein accumulation. Blockage of HIF-1alpha activity in Cyr61-expressing cells by transfecting with a dominant negative (DN)-HIF-1alpha strongly inhibited their invasion ability, suggesting that elevation in HIF-1alpha protein is vital for Cyr61-mediated gastric cancer cell invasion. In addition, several HIF-1alpha-regulated invasiveness genes were examined, and we found that only plasminogen activator inhibitor-1 (PAI-1) showed a significant increase in mRNA and protein levels in cells overexpressing Cyr61. Treatment with PAI-1-specific antisense oligonucleotides or function-neutralizing antibodies abolished the invasion ability of the Cyr61-overexpressing cells. Transfection with dominant negative-HIF-1alpha to block HIF-1alpha activity also effectively reduced the elevated PAI-1 level. In conclusion, our data provide a detailed mechanism by which Cyr61 promoted gastric cancer cell invasive ability via an HIF-1alpha-dependent up-regulation of PAI-1.
authors.affiliation: Department of Primary Care Medicine, National Taiwan University Hospital, Taipei, Taiwan.
authors.forename: Ming-Tsan
authors.initials: MT
authors.lastname: Lin
authors.forename: I-Hsin
authors.initials: IH
authors.lastname: Kuo
authors.forename: Cheng-Chi
authors.initials: CC
authors.lastname: Chang
authors.forename: Chia-Yu
authors.initials: CY
authors.lastname: Chu
authors.forename: Hsing-Yu
authors.initials: HY
authors.lastname: Chen
authors.forename: Been-Ren
authors.initials: BR
authors.lastname: Lin
authors.forename: Munisamy
authors.initials: M
authors.lastname: Sureshbabu
authors.forename: Hou-Jung
authors.initials: HJ
authors.lastname: Shih
authors.forename: Min-Liang
authors.initials: ML
authors.lastname: Kuo
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology; D045744:Cell Line, Tumor; D003035:Cobalt / Q000494:pharmacology; D003513:Cycloheximide / Q000494:pharmacology; D055515:Cysteine-Rich Protein 61; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects / Q000235:genetics; D006801:Humans; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000096:biosynthesis* / Q000235:genetics; D017874:Immediate-Early Proteins / Q000378:metabolism* / Q000494:pharmacology; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism* / Q000494:pharmacology; D007700:Kinetics; D007976:Leupeptins / Q000494:pharmacology; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000235:genetics; D009361:Neoplasm Invasiveness; D009363:Neoplasm Proteins / Q000096:biosynthesis* / Q000235:genetics; D017395:Plasminogen Activator Inhibitor 1 / Q000096:biosynthesis* / Q000235:genetics; D014176:Protein Biosynthesis / Q000187:drug effects / Q000235:genetics; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D012333:RNA, Messenger / Q000096:biosynthesis / Q000235:genetics; D011994:Recombinant Proteins / Q000378:metabolism / Q000494:pharmacology; D013274:Stomach Neoplasms / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics
chemical_list: D000970:Antineoplastic Agents; C501848:CCN1 protein, human; D055515:Cysteine-Rich Protein 61; C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D017874:Immediate-Early Proteins; D036341:Intercellular Signaling Peptides and Proteins; D007976:Leupeptins; D009363:Neoplasm Proteins; D017395:Plasminogen Activator Inhibitor 1; D011500:Protein Synthesis Inhibitors; D012333:RNA, Messenger; D011994:Recombinant Proteins; D003035:Cobalt; D003513:Cycloheximide; C018021:cobaltous chloride; C072553:benzyloxycarbonylleucyl-leucyl-leucine aldehyde