title: Knockdown of cathepsin B and uPAR inhibits CD151 and α3β1 integrin-mediated cell adhesion and invasion in glioma.
abstract: Glioma is a highly complex brain tumor characterized by the dysregulation of proteins and genes that leads to tumor metastasis. Cathepsin B and uPAR are overexpressed in gliomas and they are postulated to play central roles in glioma metastasis. In this study, efficient downregulation of cathepsin B and uPAR by siRNA treatments significantly reduced glioma cell adhesion to laminin as compared to vitronectin, fibronectin, or collagen I in U251 and 4910 glioma cell lines. Brain glioma tissue array analysis showed high expression of CD151 in clinical samples when compared with normal brain tissue. Cathepsin B and uPAR siRNA treatment led to the downregulation of CD151 and laminin-binding integrins α3 and β1. Co-immunoprecipitation experiments revealed that downregulation of cathepsin B and uPAR decreased the interaction of CD151 with uPAR cathepsin B, and α3β1 integrin. Studies on the downstream signaling cascade of uPAR/CD151/α3β1 integrin have shown that phosphorylation of FAK, SRC, paxillin, and expression of adaptor cytoskeletal proteins talin and vinculin were reduced with knockdown of cathepsin B, uPAR, and CD151. Treatment with the bicistronic construct reduced interactions between uPAR and CD151 as well as lowering α3β1 integrin, talin, and vinculin expression levels in pre-established glioma tumors of nude mice. In conclusion, our results show that downregulation of cathepsin B and uPAR alone and in combination inhibit glioma cell adhesion by downregulating CD151 and its associated signaling molecules in vitro and in vivo. Taken together, the results of the present study show that targeting the uPAR-cathepsin B system has possible therapeutic potential.
authors.affiliation: Department of Cancer Biology and Pharmacology, College of Medicine at Peoria, University of Illinois, Peoria, IL.
authors.forename: Rama
authors.initials: R
authors.lastname: Rao Malla
authors.forename: Sreelatha
authors.initials: S
authors.lastname: Gopinath
authors.forename: Kiranmai
authors.initials: K
authors.lastname: Alapati
authors.forename: Bharathi
authors.initials: B
authors.lastname: Gorantla
authors.forename: Christopher S
authors.initials: CS
authors.lastname: Gondi
authors.forename: Jasti S
authors.initials: JS
authors.lastname: Rao
mesh_terms: D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D001932:Brain Neoplasms / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D002401:Cathepsin B / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000378:metabolism; D002465:Cell Movement; D049109:Cell Proliferation; D015536:Down-Regulation; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D051416:Focal Adhesion Protein-Tyrosine Kinases / Q000378:metabolism; D005910:Glioma / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D039201:Integrin alpha3beta1 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D008819:Mice, Nude; D010766:Phosphorylation; D034741:RNA, Small Interfering / Q000235:genetics; D055293:Receptors, Urokinase Plasminogen Activator / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D060185:Tetraspanin 24 / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D014407:Tumor Cells, Cultured; D000097794:Kalinin
chemical_list: D002401:Cathepsin B; D015815:Cell Adhesion Molecules; D051416:Focal Adhesion Protein-Tyrosine Kinases; D039201:Integrin alpha3beta1; D034741:RNA, Small Interfering; D055293:Receptors, Urokinase Plasminogen Activator; D060185:Tetraspanin 24; D000097794:Kalinin; C554715:CD151 protein, human