title: JNK signaling pathway is required for bFGF-mediated surface cadherin downregulation on HUVEC.
abstract: Angiogenesis, the process of new blood vessel formation, is important in wound healing, inflammation, tumorigenesis and metastases. During this process, it is a critical step of the loosening of cellular interactions between endothelial cells, which are dependent on the architecture of adherens junction constructed by homophilic interactions of cell surface cadherins. Several studies suggested that the dynamic changes of cadherins are necessary during angiogenesis. However, the mechanism of cadherins regulation on endothelial cells requires further delineation. Here, we showed that basic fibroblast growth factor (bFGF), a pivotal pro-angiogenic factor, can downregulate typical cadherins (E-, N-, P- and VE-cadherin) expression on the surface of human umbilical vein endothelial cells (HUVECs) via FGF receptor 1 (FGFR1) signaling. The bFGF-mediated surface cadherin downregulation was significantly reversed only when the HUVECs were treated with JNK inhibitor (SP600125), but not ERK (PD98059) or p38 inhibitor (SB203580). Infecting HUVECs with a dominant negative H-Ras mutant (Ras(S17N)) interferes bFGF-mediated cadherin downregulation, and the result suggests that bFGF attenuates surface cadherin expression on HUVECs via FGFR1 and intracellular Ras-JNK signaling. However, after growth factors withdrawal, FGFR1 blockade or JNK inhibition for 16 h, cadherins were re-expressed on cell surface of HUVECs. But the mRNA or total protein of cadherins had no significant change, suggesting that the effect of bFGF on cadherin expression may work through a post-translational control. Our data first suggest that JNK participates in bFGF-mediated surface cadherin downregulation. Loss of surface cadherins may affect the cell-cell interaction between endothelial cells and facilitate angiogenesis.
authors.affiliation: Graduate Institute of Life Science, National Defense Medical Center, Taipei, Taiwan.
authors.forename: Jen-Chine
authors.initials: JC
authors.lastname: Wu
authors.forename: Horng-Chin
authors.initials: HC
authors.lastname: Yan
authors.forename: Wei-Teing
authors.initials: WT
authors.lastname: Chen
authors.forename: Wei-Hwa
authors.initials: WH
authors.lastname: Chen
authors.forename: Chia-Jen
authors.initials: CJ
authors.lastname: Wang
authors.forename: Ying-Chih
authors.initials: YC
authors.lastname: Chi
authors.forename: Woei-Yau
authors.initials: WY
authors.lastname: Kao
mesh_terms: D022005:Adherens Junctions / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D000873:Anthracenes / Q000494:pharmacology; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002450:Cell Communication / Q000502:physiology; D002478:Cells, Cultured; D015536:Down-Regulation / Q000502:physiology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004791:Enzyme Inhibitors / Q000494:pharmacology; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism* / Q000494:pharmacology; D006801:Humans; D007231:Infant, Newborn; D048031:JNK Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D018919:Neovascularization, Physiologic / Q000502:physiology*; D011499:Protein Processing, Post-Translational / Q000187:drug effects / Q000502:physiology; D012333:RNA, Messenger / Q000187:drug effects / Q000378:metabolism; D051496:Receptor, Fibroblast Growth Factor, Type 1 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology; D020663:ras Guanine Nucleotide Exchange Factors / Q000235:genetics
chemical_list: D000873:Anthracenes; D015820:Cadherins; D004791:Enzyme Inhibitors; D012333:RNA, Messenger; D020663:ras Guanine Nucleotide Exchange Factors; D016222:Fibroblast Growth Factor 2; C432165:pyrazolanthrone; C496348:FGFR1 protein, human; D051496:Receptor, Fibroblast Growth Factor, Type 1; D048031:JNK Mitogen-Activated Protein Kinases