title: Inhibition of immunosuppressive effects of melanoma-inhibiting activity (MIA) by antisense techniques.
abstract: Melanoma inhibitory activity (MIA) is an 11 kD protein secreted by malignant melanomas. Recent studies revealed an interaction of MIA with epitopes of extracellular matrix proteins including fibronectin. Structural homology of MIA with the binding sites of alpha4beta1 integrin results in complex interactions of MIA with molecules binding to alpha4beta1 integrin. As cells of the immune system express alpha4beta1 integrins (VLA-4), we investigated whether MIA may modulate the function of human leukocytes. Here we describe the effects of MIA on the activation of human PBMCs and auto-/allogeneic lymphokine-activated killer cell (LAK) cytotoxicity in human MIA-negative glioma cell lines and MIA-positive melanoma cell lines in vitro. MIA inhibits PHA- or IL-2-induced human PBMC proliferation in a dose-dependent manner up to 63% ((3)H-Tdr incorporation) and 59% (cell count), respectively, when added to the cell culture prior to mitogen stimulation. In addition, both autologous (GL and HW) and allogeneic (HTZ-17, HTZ-243 and HTZ-374) antitumor LAK cytotoxicity was reduced by the addition of exogenous rhMIA (500 ng/ml, f.c.). Consequently, endogenous inhibition of MIA expression in human melanoma cells by MIA-specific phosphorothioate antisense oligonucleotides enhanced the autologous LAK-cell activity to the same level as observed in MIA-negative human HMB melanoma cells expressing an MIA-antisense construct. Our results indicate that MIA may contribute to immunosuppression frequently seen in malignant melanomas by inhibiting cellular antitumor immune reactions. Antagonization of MIA activity using antisense techniques may represent a novel therapeutic strategy for treatment of malignant melanomas.
authors.affiliation: Antisense Pharma GmbH, Regensburg, Germany. Jachimczak@t-online.de
authors.forename: Piotr
authors.initials: P
authors.lastname: Jachimczak
authors.forename: Rainer
authors.initials: R
authors.lastname: Apfel
authors.forename: Anja-Kathrin
authors.initials: AK
authors.lastname: Bosserhoff
authors.forename: Klaus
authors.initials: K
authors.lastname: Fabel
authors.forename: Peter
authors.initials: P
authors.lastname: Hau
authors.forename: Ines
authors.initials: I
authors.lastname: Tschertner
authors.forename: Petra
authors.initials: P
authors.lastname: Wise
authors.forename: Karl-Hermann
authors.initials: KH
authors.lastname: Schlingensiepen
authors.forename: Beatrix
authors.initials: B
authors.lastname: Schuler-Thurner
authors.forename: Ulrich
authors.initials: U
authors.lastname: Bogdahn
mesh_terms: D045744:Cell Line, Tumor; D003602:Cytotoxicity, Immunologic; D016326:Extracellular Matrix Proteins; D015972:Gene Expression Regulation, Neoplastic; D005910:Glioma / Q000276:immunology / Q000378:metabolism*; D006801:Humans; D007376:Interleukin-2 / Q000378:metabolism*; D015979:Killer Cells, Lymphokine-Activated / Q000276:immunology; D007963:Leukocytes, Mononuclear / Q000276:immunology*; D008213:Lymphocyte Activation; D008545:Melanoma / Q000276:immunology / Q000378:metabolism*; D009363:Neoplasm Proteins; D016376:Oligonucleotides, Antisense / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism; D011506:Proteins / Q000037:antagonists & inhibitors* / Q000276:immunology*; D011994:Recombinant Proteins / Q000037:antagonists & inhibitors / Q000276:immunology; D013873:Thionucleotides
chemical_list: D016326:Extracellular Matrix Proteins; D007376:Interleukin-2; C090059:MIA protein, human; D009363:Neoplasm Proteins; D016376:Oligonucleotides, Antisense; D010710:Phosphates; D011506:Proteins; D011994:Recombinant Proteins; D013873:Thionucleotides; C083120:phosphorodithioic acid