title: uPAR/cathepsin B overexpression reverse angiogenesis by rescuing FAK phosphorylation in uPAR/cathepsin B down regulated meningioma.
abstract: BACKGROUND
  Meningiomas are the most commonly occurring intracranial tumors and account for approximately 15-20% of central nervous system tumors. Surgery and radiation therapy is a common treatment for brain tumors, however, patients whose tumors recur after such treatments have limited therapeutic options. Earlier studies have reported important roles of uPA, uPAR and cathepsin B in tumor progression.
  
  
  RESULTS
  In the present study, we examined the therapeutic significance of RNAi-mediated simultaneous down regulation of these proteolytic networks using two bicistronic siRNA constructs, pUC (uPAR/cathepsin B) and pU2 (uPA/uPAR) either alone or in combination with radiation in two different meningioma cell lines. Transfection of meningioma cells with pUC and pU2 significantly reduced angiogenesis as compared to control treatment both in vitro and in vivo nude mice model. This effect is mediated by inhibiting angiogenic molecules (Ang-1, Ang-2 and VEGF). Expression of focal adhesion kinase (FAK) is elevated in malignant meningioma, yet the role of intrinsic FAK activity in promoting tumor progression remains undefined. We found that pUC treatment reduced FAK phosphorylation at Y925 more efficiently compared to pU2 treatment. In immunoprecipitation assay, we found pronounced reduction of FAK (Y925) interaction with Grb2 in meningioma cells transfected with pUC with and without irradiation. Transient over-expression of uPAR and cathepsin B by full length uPAR/cathepsin B (FLpU/C) in pUC transfected meningioma cells promoted vascular phenotype, rescued expression of Ang-1, Ang-2, VEGF, FAK (Y925) and Grb2 both in vitro and in vivo mice model.
  
  
  CONCLUSIONS
  These studies provide the first direct proof that bicistronic siRNA construct for uPAR and cathepsin B (pUC) reduces Y925-FAK activity and this inhibition is rescued by overexpression of both uPAR and cathepsin B which clearly demonstrates that pUC could thus be a potential therapeutic approach as an anti-angiogenic agent in meningioma.
authors.affiliation: Department of Cancer Biology and Pharmacology, University of Illinois College of Medicine at Peoria, Peoria, Illinois, United States of America.
authors.forename: Reshu
authors.initials: R
authors.lastname: Gupta
authors.forename: Arun Kumar
authors.initials: AK
authors.lastname: Nalla
authors.forename: Venkateswara Rao
authors.initials: VR
authors.lastname: Gogineni
authors.forename: Chandramu
authors.initials: C
authors.lastname: Chetty
authors.forename: Praveen
authors.initials: P
authors.lastname: Bhoopathi
authors.forename: Jeffrey D
authors.initials: JD
authors.lastname: Klopfenstein
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Tsung
authors.forename: Sanjeeva
authors.initials: S
authors.lastname: Mohanam
authors.forename: Jasti S
authors.initials: JS
authors.lastname: Rao
mesh_terms: D000818:Animals; D002401:Cathepsin B / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*; D045744:Cell Line, Tumor; D015536:Down-Regulation / Q000528:radiation effects; D005260:Female; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism*; D051380:GRB2 Adaptor Protein / Q000378:metabolism; D015972:Gene Expression Regulation, Neoplastic / Q000235:genetics* / Q000528:radiation effects; D006801:Humans; D008577:Meningeal Neoplasms / Q000098:blood supply / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D008579:Meningioma / Q000098:blood supply* / Q000235:genetics / Q000378:metabolism* / Q000473:pathology; D051379:Mice; D009389:Neovascularization, Pathologic / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation / Q000235:genetics / Q000528:radiation effects; D034622:RNA Interference; D034741:RNA, Small Interfering / Q000235:genetics; D055293:Receptors, Urokinase Plasminogen Activator / Q000172:deficiency / Q000235:genetics / Q000378:metabolism*
chemical_list: D051380:GRB2 Adaptor Protein; D034741:RNA, Small Interfering; D055293:Receptors, Urokinase Plasminogen Activator; D051416:Focal Adhesion Protein-Tyrosine Kinases; D002401:Cathepsin B