title: Glioma cancer stem cells induce immunosuppressive macrophages/microglia.
abstract: Macrophages (MΦs)/microglia that constitute the dominant tumor-infiltrating immune cells in glioblastoma are recruited by tumor-secreted factors and are induced to become immunosuppressive and tumor supportive (M2). Glioma cancer stem cells (gCSCs) have been shown to suppress adaptive immunity, but their role in innate immunity with respect to the recruitment and polarization of MΦs/microglia is unknown. The innate immunosuppressive properties of the gCSCs were characterized based on elaborated MΦ inhibitory cytokine-1 (MIC-1), transforming growth factor (TGF-β1), soluble colony-stimulating factor (sCSF), recruitment of monocytes, inhibition of MΦ/microglia phagocytosis, induction of MΦ/microglia cytokine secretion, and the inhibition of T-cell proliferation. The role of the signal transducer and activator of transcription 3 (STAT3) in mediating innate immune suppression was evaluated in the context of the functional assays. The gCSCs produced sCSF-1, TGF-β1, and MIC-1, cytokines known to recruit and polarize the MΦs/microglia to become immunosuppressive. The gCSC-conditioned medium polarized the MΦ/microglia to an M2 phenotype, inhibited MΦ/microglia phagocytosis, induced the secretion of the immunosuppressive cytokines interleukin-10 (IL-10) and TGF-β1 by the MΦs/microglia, and enhanced the capacity of MΦs/microglia to inhibit T-cell proliferation. The inhibition of phagocytosis and the secretion of IL-10 were reversed when the STAT3 pathway was blocked in the gCSCs. The gCSCs modulate innate immunity in glioblastoma by inducing immunosuppressive MΦs/microglia, and this capacity can be reversed by inhibiting phosphorylated STAT3.
authors.affiliation: Department of Neurosurgery, The University of Texas MD Anderson Cancer Center, Houston, TX 77030, USA.
authors.forename: Adam
authors.initials: A
authors.lastname: Wu
authors.forename: Jun
authors.initials: J
authors.lastname: Wei
authors.forename: Ling-Yuan
authors.initials: LY
authors.lastname: Kong
authors.forename: Yongtao
authors.initials: Y
authors.lastname: Wang
authors.forename: Waldemar
authors.initials: W
authors.lastname: Priebe
authors.forename: Wei
authors.initials: W
authors.lastname: Qiao
authors.forename: Raymond
authors.initials: R
authors.lastname: Sawaya
authors.forename: Amy B
authors.initials: AB
authors.lastname: Heimberger
mesh_terms: D015153:Blotting, Western; D001932:Brain Neoplasms / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D002465:Cell Movement / Q000276:immunology; D002469:Cell Separation; D002478:Cells, Cultured; D002630:Chemotactic Factors / Q000276:immunology / Q000378:metabolism; D002634:Chemotaxis, Leukocyte / Q000276:immunology; D016207:Cytokines / Q000096:biosynthesis / Q000276:immunology; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D005910:Glioma / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D006801:Humans; D007113:Immunity, Innate / Q000276:immunology; D008264:Macrophages / Q000276:immunology* / Q000378:metabolism; D017628:Microglia / Q000276:immunology* / Q000378:metabolism; D014411:Neoplastic Stem Cells / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D010766:Phosphorylation; D050796:STAT3 Transcription Factor / Q000276:immunology / Q000378:metabolism; D015398:Signal Transduction / Q000276:immunology; D014162:Transfection
chemical_list: D002630:Chemotactic Factors; D016207:Cytokines; D050796:STAT3 Transcription Factor; C494086:STAT3 protein, human