title: Membrane proteome analysis of glioblastoma cell invasion.
abstract: Glioblastoma multiforme (GBM) tumor invasion is facilitated by cell migration and degradation of the extracellular matrix. Invadopodia are actin-rich structures that protrude from the plasma membrane in direct contact with the extracellular matrix and are proposed to participate in epithelial-mesenchymal transition. We characterized the invasiveness of 9 established GBM cell lines using an invadopodia assay and performed quantitative mass spectrometry-based proteomic analyses on enriched membrane fractions. All GBM cells produced invadopodia, with a 65% difference between the most invasive cell line (U87MG) and the least invasive cell line (LN229) (p = 0.0001). Overall, 1,141 proteins were identified in the GBM membrane proteome; the levels of 49 proteins correlated with cell invasiveness. Ingenuity Pathway Analysis predicted activation "cell movement" (z-score = 2.608, p = 3.94E(-04)) in more invasive cells and generated a network of invasion-associated proteins with direct links to key regulators of invadopodia formation. Gene expression data relating to the invasion-associated proteins ITGA5 (integrin α5), CD97, and ANXA1 (annexin A1) showed prognostic significance in independent GBM cohorts. Fluorescence microscopy demonstrated ITGA5, CD97, and ANXA1 localization in invadopodia assays, and small interfering RNA knockdown of ITGA5 reduced invadopodia formation in U87MG cells. Thus, invasion-associated proteins, including ITGA5, may prove to be useful anti-invasive targets; volociximab, a therapeutic antibody against integrin α5β1, may be useful for treatment of patients with GBM.
authors: From the Cancer Proteomics Laboratory, School of Molecular Bioscience (DMM, EKS, RIC, KLK), and Brain and Mind Research Institute (MEB, LL, KLK), The University of Sydney; Department of Neuropathology, Royal Prince Alfred Hospital (MEB, CCYL, KLK), Camperdown; and Cure Brain Cancer Laboratory, Lowy Cancer Research Center, Prince of Wales Clinical School, University of New South Wales, Sydney (KLM), New South Wales, Australia.
authors: Duthika M
authors: DM
authors: Mallawaaratchy
authors: Michael E
authors: ME
authors: Buckland
authors: Kerrie L
authors: KL
authors: McDonald
authors: Cheryl C Y
authors: CC
authors: Li
authors: Linda
authors: L
authors: Ly
authors: Erin K
authors: EK
authors: Sykes
authors: Richard I
authors: RI
authors: Christopherson
authors: Kimberley L
authors: KL
authors: Kaufman
mesh_terms: D017305:Annexin A1 / Q000235:genetics / Q000378:metabolism; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism; D001932:Brain Neoplasms / Q000473:pathology*; D045744:Cell Line, Tumor; D030562:Databases, Protein / Q000706:statistics & numerical data; D015972:Gene Expression Regulation, Neoplastic; D005909:Glioblastoma / Q000473:pathology*; D006801:Humans; D008297:Male; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism*; D008875:Middle Aged; D009361:Neoplasm Invasiveness / Q000473:pathology*; D040901:Proteomics / Q000379:methods; D034741:RNA, Small Interfering / Q000235:genetics / Q000378:metabolism; D053719:Tandem Mass Spectrometry; D014162:Transfection
chemical_list: D017305:Annexin A1; D015703:Antigens, CD; D008565:Membrane Proteins; D034741:RNA, Small Interfering