title: Sweet escape: sialic acids in tumor immune evasion.
abstract: Sialic acids represent a family of sugar molecules derived from neuraminic acid that frequently terminate glycan chains and contribute to many biological processes. Already five decades ago, aberrantly high expression of sialic acids has been proposed to protect cancer cells from recognition and eradication by the immune system. Today, increased understanding at the molecular level demonstrates the broad immunomodulatory capacity of tumor-derived sialic acids that is, at least in part, mediated through interactions with immunoinhibitory Siglec receptors. Here we will review current studies from a sialic acid sugar perspective showing that tumor-derived sialic acids disable major killing mechanisms of effector immune cells, trigger production of immune suppressive cytokines and dampen activation of antigen-presenting cells and subsequent induction of anti-tumor immune responses. Furthermore, strategies to modulate sialic acid expression in cancer cells to improve cancer immunotherapy will be discussed.
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Christian
authors.initials: C
authors.lastname: Büll
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: Martijn H
authors.initials: MH
authors.lastname: den Brok
authors.affiliation: Department of Tumor Immunology, Radboud Institute for Molecular Life Sciences, Radboud University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands. Electronic address: g.adema@ncmls.ru.nl.
authors.forename: Gosse J
authors.initials: GJ
authors.lastname: Adema
mesh_terms: D000818:Animals; D003165:Complement System Proteins / Q000276:immunology / Q000378:metabolism; D003713:Dendritic Cells / Q000276:immunology; D006801:Humans; D007107:Immune System / Q000378:metabolism; D007167:Immunotherapy; D022423:Myeloid Cells / Q000276:immunology; D009369:Neoplasms / Q000276:immunology / Q000628:therapy; D012794:Sialic Acids / Q000378:metabolism*; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology / Q000378:metabolism; D019139:Tumor Escape / Q000276:immunology
chemical_list: D012794:Sialic Acids; D003165:Complement System Proteins
keywords: Cancer; Immune evasion; Sialic acids; Sialoglycans; Siglecs; Tumor microenvironment