Milan Stefanović1*, Ivan Jovanović1, Aleksandra Stanković1 and Maja Živković1
1Institute for nuclear sciences ’’Vinča’’, National institite of the Republic of Serbia, Laboratory for radiobiology and molecular genetics, Mike Petrovića Alasa 12-14, 11351 Vinča, Beograd, Srbija
milanst [at] vin.bg.ac.rs
Abstract
The significance of CD8+ T cell central nervous system migration and activation in the progression of glioblastoma is well documented. However, molecular signaling pathways regulation related to migration and activation in CD8+ cells in glioblastoma is scarce. Therefore we have analyzed the molecular pathway regulation in differentially expressed mRNAs of tumor infiltrating vs. peripheral blood CD8+ T cells from glioblastoma patients.
Tumor-infiltrating vs. peripheral blood differentially expressed mRNAs were obtained by analyzing the FASTAQ files on the Galaxy platform using the LimmaVoom tool with filtering low count mRNAs (CPM > 2). We used publically avaliable FASTAQ files with CD8+ T cells mRNA sequencing data deposited at NCBI’s GEO database (accession number GSE171197). The differentially expressed mRNA were analyzed with Qiagen’s Ingenuity pathway analysis (p adj. cutoff 0.05). Protein-protein interaction network was constructed on the NetworkAnalyst platform using the IMeX database with minimal order parameters.
The top rated disease canonical pathway was the multiple sclerosis (MS) signaling pathway, with 18 differentially expressed mRNA hits (out of possible 222), p adj. = 0.0009 and Z score = 2.828, implying significant upregulation of this pathway in tumor-infiltrating CD8+ T cells.
The MS signaling pathway describes the molecular cascade which leads to the autoimmune phenotype in lymphocytes, including activation and central nervous tissue infiltration. To further specify the aspects of the canonical MS signaling pathway which might influence tumor infiltrating phenotype we have constructed a minimal order protein-protein interaction network. Results showed a number of lymphocyte migration and activation KEGG terms within the network, such as: TNF signaling pathway (p adj. = 0.0000115), IL-17 signaling pathway (p adj. = 0.00000427), sphingolipid signaling pathway (p adj. = 0.00171), NF-kappa B signaling pathway (p adj. = 0.0000694) and TCR signaling pathway (p adj. = 0.0071).
We conclude that MS signaling pathway is an viable model for further understanding of the transcriptional phenotype of glioblastoma infiltrating CD8+ T killer cells, illustrating that same migration and activation mechanisms which mediate brain autoimmunity are essential for brain antitumor adaptive immunity.
Keywords: glioblastoma, multiple sclerosis, enrichment analysis, network analysis
