title: Cryptotanshinone inhibits lymphatic endothelial cell tube formation by suppressing VEGFR-3/ERK and small GTPase pathways.
abstract: Cryptotanshinone (CPT), isolated from the plant Salvia miltiorrhiza Bunge, is a potential anticancer agent. However, the underlying mechanism remains to be defined. Here, we show that CPT inhibited lymphangiogenesis in an in vitro model (tube formation). This effect was partly attributed to inhibiting expression of VEGF receptor 3 (VEGFR-3) in murine lymphatic endothelial cells (LEC), as overexpression of VEGFR-3 conferred resistance to CPT inhibition of the tube formation, whereas downregulation of VEGFR-3 mimicked the effect of CPT, blocking the tube formation. Furthermore, CPT inhibited phosphorylation of the extracellular signal-related kinase 1/2 (ERK1/2). Overexpression of VEGFR-3 attenuated CPT inhibition of ERK1/2 phosphorylation, whereas downregulation of VEGFR-3 inhibited ERK1/2 phosphorylation in LECs. Expression of constitutively active MKK1 resulted in activation of ERK1/2 and partially prevented CPT inhibition of LEC tube formation. In addition, CPT also inhibited protein expression and activities of Rac1 and Cdc42 but not RhoA. Expression of constitutively active Rac1 and Cdc42 concurrently, but not Rac1 or Cdc42 alone, conferred resistance to CPT inhibition of LEC tube formation. Taken together, the results suggest that CPT inhibits LEC tube formation, in part, by inhibiting VEGFR-3-mediated ERK1/2 phosphorylation and, in part, by inhibiting expression of the small GTPases.
authors: Key Laboratory of Biotherapy, West China Hospital, Sichuan University, Chengdu, Sichuan Province, PR China.
authors: Yan
authors: Y
authors: Luo
authors: Wenxing
authors: W
authors: Chen
authors: Hongyu
authors: H
authors: Zhou
authors: Lei
authors: L
authors: Liu
authors: Tao
authors: T
authors: Shen
authors: J Steven
authors: JS
authors: Alexander
authors: Shizhong
authors: S
authors: Zheng
authors: Yin
authors: Y
authors: Lu
authors: Shile
authors: S
authors: Huang
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D004365:Drugs, Chinese Herbal; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D048052:Mitogen-Activated Protein Kinase 3 / Q000037:antagonists & inhibitors / Q000378:metabolism*; D009479:Neuropeptides / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D010616:Phenanthrenes / Q000494:pharmacology*; D010766:Phosphorylation / Q000187:drug effects; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction / Q000187:drug effects; D042461:Vascular Endothelial Growth Factor A / Q000378:metabolism; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000378:metabolism; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020764:cdc42 GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020744:rac GTP-Binding Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D020830:rac1 GTP-Binding Protein
chemical_list: D004365:Drugs, Chinese Herbal; D009479:Neuropeptides; D010616:Phenanthrenes; D034741:RNA, Small Interfering; C484602:Rac1 protein, mouse; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; C037886:cryptotanshinone; D040301:Vascular Endothelial Growth Factor Receptor-2; D040321:Vascular Endothelial Growth Factor Receptor-3; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020764:cdc42 GTP-Binding Protein; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein