title: Opposing effects of interferon-alpha and interferon-gamma on the expression of major histocompatibility complex class I chain-related A in tumors.
abstract: Natural killer cells are an important component of innate resistance to viruses, bacteria, certain parasites, and tumors. The activating receptor natural killer group 2D (NKG2D) plays a critical role in the elimination of tumor cells by cytotoxic effector cells. It has been shown that the strength of an antitumor immune response might be critically dependent on NKG2D ligard surface levels. Thus, it is essential to regulate the expression of NKG2D ligands in order to ensure effective tumor immunosurveillance and the elimination of pathogen-infected cells. In the present study, we found that interferon (IFN)-alpha and IFNgamma exert opposing effects on major histocompatibility complex class I-related chain A (MICA) expression in human tumor cells. IFNalpha promotes expression of the NKG2D ligand MICA in tumor cells and therefore enhances their sensitivity to natural killer lysis. In contrast, IFNgamma exerts the opposite effect. IFNalpha promotes MICA expression at the level of transcription by augmenting MICA promoter activity. IFNgamma modulates MICA expression not only at the transcriptional level, but also at the post-translational level by promoting proteolytic cleavage by matrix metalloproteinases. Further study is needed to clarify the precise regulatory mechanisms. The pathways involved in NKG2D ligand induction might represent a promising target for improving immune responses to cancer or infections.
authors.affiliation: Institute of Immunopharmacology and Immunotherapy, School of Pharmaceutical Sciences, Shandong University, 44 Wenhua West Road, Jinan 250012, China. caizhangsd@yahoo.com.cn
authors.forename: Cai
authors.initials: C
authors.lastname: Zhang
authors.forename: Jiafeng
authors.initials: J
authors.lastname: Niu
authors.forename: Jianhua
authors.initials: J
authors.lastname: Zhang
authors.forename: Yiping
authors.initials: Y
authors.lastname: Wang
authors.forename: Zhixia
authors.initials: Z
authors.lastname: Zhou
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.forename: Zhigang
authors.initials: Z
authors.lastname: Tian
mesh_terms: D000970:Antineoplastic Agents / Q000494:pharmacology*; D015153:Blotting, Western; D002478:Cells, Cultured; D003602:Cytotoxicity, Immunologic; D004797:Enzyme-Linked Immunosorbent Assay; D005434:Flow Cytometry; D015395:Histocompatibility Antigens Class I / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D007370:Interferon Type I / Q000494:pharmacology*; D007371:Interferon-gamma / Q000494:pharmacology*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000378:metabolism; D008156:Luciferases / Q000378:metabolism; D045726:Metalloproteases / Q000378:metabolism; D055655:NK Cell Lectin-Like Receptor Subfamily K; D009369:Neoplasms / Q000188:drug therapy* / Q000378:metabolism* / Q000473:pathology; D011401:Promoter Regions, Genetic; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D011971:Receptors, Immunologic / Q000378:metabolism; D055607:Receptors, Natural Killer Cell; D011994:Recombinant Proteins; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014162:Transfection
chemical_list: D000970:Antineoplastic Agents; D015395:Histocompatibility Antigens Class I; D007370:Interferon Type I; C527085:KLRK1 protein, human; C099187:MHC class I-related chain A; D055655:NK Cell Lectin-Like Receptor Subfamily K; D012333:RNA, Messenger; D011971:Receptors, Immunologic; D055607:Receptors, Natural Killer Cell; D011994:Recombinant Proteins; D007371:Interferon-gamma; D008156:Luciferases; D045726:Metalloproteases