title: Definition of a serum marker panel for glioblastoma discrimination and identification of Interleukin 1β in the microglial secretome as a novel mediator of endothelial cell survival induced by C-reactive protein.
abstract: Glioblastoma (GBM) is the most common malignant adult primary brain tumor. We profiled 724 cancer-associated proteins in sera of healthy individuals (n=27) and GBM (n=28) using antibody microarray. While 69 proteins exhibited differential abundance in GBM sera, a three-marker panel (LYAM1, BHE40 and CRP) could discriminate GBM sera from that of healthy donors with an accuracy of 89.7% and p<0.0001. The high abundance of C-reactive protein (CRP) in GBM sera was confirmed in 264 independent samples. High levels of CRP protein was seen in GBM but without a change in transcript levels suggesting a non-tumoral origin. Glioma-secreted Interleukin 6 (IL6) was found to induce hepatocytes to secrete CRP, involving JAK-STAT pathway. The culture supernatant from CRP-treated microglial cells induced endothelial cell survival under nutrient-deprivation condition involving CRP-FcγRIII signaling cascade. Transcript profiling of CRP-treated microglial cells identified Interleukin 1β (IL1β) present in the microglial secretome as the key mediator of CRP-induced endothelial cell survival. IL1β neutralization by antibody-binding or siRNA-mediated silencing in microglial cells reduced the ability of the supernatant from CRP-treated microglial cells to induce endothelial cell survival. Thus our study identifies a serum based three-marker panel for GBM diagnosis and provides leads for developing targeted therapies. Biological significance A complex antibody microarray based serum marker profiling identified a three-marker panel - LYAM1, BHE40 and CRP as an accurate discriminator of glioblastoma sera from that of healthy individuals. CRP protein is seen in high levels without a concomitant increase of CRP transcripts in glioblastoma. Glioma-secreted IL6 induced hepatocytes to produce CRP in a JAK-STAT signaling dependent manner. CRP induced microglial cells to release IL1β which in turn promoted endothelial cell survival. This study, besides defining a serum panel for glioblastoma discrimination, identified IL1β as a potential candidate for developing targeted therapy.
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Mamatha B
authors.initials: MB
authors.lastname: Nijaguna
authors.affiliation: Functional Genome Analysis, Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany.
authors.forename: Christoph
authors.initials: C
authors.lastname: Schröder
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India.
authors.forename: Vikas
authors.initials: V
authors.lastname: Patil
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and Neuro Sciences, Bangalore 560029, India.
authors.forename: Shivayogi D
authors.initials: SD
authors.lastname: Shwetha
authors.affiliation: Sri Satya Sai Institute of Higher Medical Sciences, Bangalore 560066, India.
authors.forename: Alangar S
authors.initials: AS
authors.lastname: Hegde
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neuro Sciences, Bangalore 560029, India.
authors.forename: Bangalore A
authors.initials: BA
authors.lastname: Chandramouli
authors.affiliation: Department of Neurosurgery, National Institute of Mental Health and Neuro Sciences, Bangalore 560029, India.
authors.forename: Arimappamagan
authors.initials: A
authors.lastname: Arivazhagan
authors.affiliation: Department of Neuropathology, National Institute of Mental Health and Neuro Sciences, Bangalore 560029, India.
authors.forename: Vani
authors.initials: V
authors.lastname: Santosh
authors.affiliation: Functional Genome Analysis, Deutsches Krebsforschungszentrum (DKFZ), Im Neuenheimer Feld 580, 69120 Heidelberg, Germany. Electronic address: j.hoheisel@dkfz.de.
authors.forename: Jörg D
authors.initials: JD
authors.lastname: Hoheisel
authors.affiliation: Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India. Electronic address: skumar@mcbl.iisc.ernet.in.
authors.forename: Kumaravel
authors.initials: K
authors.lastname: Somasundaram
mesh_terms: D015415:Biomarkers / Q000097:blood; D014408:Biomarkers, Tumor / Q000097:blood*; D002097:C-Reactive Protein / Q000378:metabolism*; D045744:Cell Line, Tumor; D002470:Cell Survival; D042783:Endothelial Cells / Q000378:metabolism*; D005909:Glioblastoma / Q000097:blood* / Q000175:diagnosis*; D006801:Humans; D053583:Interleukin-1beta; D017628:Microglia / Q000378:metabolism*; D020543:Proteome / Q000378:metabolism; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity
chemical_list: D015415:Biomarkers; D014408:Biomarkers, Tumor; D053583:Interleukin-1beta; D020543:Proteome; D002097:C-Reactive Protein
keywords: Antibody microarray; Biomarker; Brain tumor; CRP; Endothelial cell; Glioma; IL1β; Microglia; Stromal cell