title: Fas/APO-1 gene transfer for human malignant glioma.
abstract: Human malignant glioma cells are susceptible to apoptosis induced by antibodies to Fas/APO-1, a cytokine receptor protein of the nerve growth factor/tumor necrosis factor receptor superfamily. Here we show that a critical level of cell surface expression of Fas/APO-1 is a prerequisite for induction of glioma cell apoptosis via Fas/APO-1. Although Fas/APO-1 mRNA was expressed in three Fas/APO-1 antibody-resistant glioma cell lines, these cells expressed either little Fas/APO-1 protein (LN-319 and LN-405) or an abnormal Fas/APO-1 protein that was not translocated to the cell membrane and therefore functionally inactive (LN-308). Although all glioma cell lines expressed mRNA for Fas/APO-1-delta TM, a soluble form of Fas/APO-1 lacking the transmembrane domain, none of the cell lines released detectable amounts of soluble Fas/APO-1, a potential endogenous antagonist of Fas/APO-1-mediated glioma cell apoptosis. Stable transfection of three resistant glioma cell lines with a human Fas/APO-1 cDNA expression vector dramatically enhanced cell surface expression of Fas/APO-1 and induced susceptibility to Fas/APO-1 antibody-mediated apoptosis. These data indicate that malignant glioma cells, unlike other tumor cells, uniformly harbor the intracellular cascade required for Fas/APO-1-mediated apoptosis. Low level of Fas/APO-1 expression results from inefficient transcription and translation of the Fas/APO-1 gene or the synthesis of mutant Fas/APO-1 proteins. gamma-Interferon, tumor necrosis factor-alpha, and interleukin 1 beta augmented Fas/APO-1-mediated apoptosis of Fas/APO-1-transfected glioma cells by acting on the subcellular suicidal cascade triggered by Fas/APO-1 activation. Dexamethasone attenuated Fas/APO-1 antibody-induced apoptosis, not only of constitutively Fas/APO-1-positive glioma cells, but also of Fas/APO-1-transfected glioma cells. The antiapoptotic effect of dexamethasone could be overcome by preexposure of the glioma cells to gamma-interferon or by coexposure to Fas/APO-1 antibodies and cycloheximide. Thus, Fas/APO-1 gene transfer and combined immunotherapy using Fas/APO-1 antibodies and cytokines may overcome Fas/APO-1 antibody resistance of Fas/APO-1-negative human malignant glioma cells, which may represent subpopulations within single gliomas or form a separate subgroup of human malignant gliomas.
authors.affiliation: Department of Internal Medicine, University Hospital, Zürich, Switzerland.
authors.forename: M
authors.initials: M
authors.lastname: Weller
authors.forename: U
authors.initials: U
authors.lastname: Malipiero
authors.forename: A
authors.initials: A
authors.lastname: Rensing-Ehl
authors.forename: P J
authors.initials: PJ
authors.lastname: Barr
authors.forename: A
authors.initials: A
authors.lastname: Fontana
mesh_terms: D000906:Antibodies / Q000008:administration & dosage; D000954:Antigens, Surface / Q000008:administration & dosage* / Q000235:genetics; D017209:Apoptosis; D001483:Base Sequence; D003513:Cycloheximide / Q000494:pharmacology; D017931:DNA Primers / Q000737:chemistry; D003907:Dexamethasone / Q000494:pharmacology; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005910:Glioma / Q000235:genetics / Q000628:therapy*; D006801:Humans; D066298:In Vitro Techniques; D007371:Interferon-gamma / Q000494:pharmacology; D008562:Membrane Glycoproteins / Q000378:metabolism; D008969:Molecular Sequence Data; D014407:Tumor Cells, Cultured; D019014:fas Receptor
chemical_list: D000906:Antibodies; D000954:Antigens, Surface; D017931:DNA Primers; D008562:Membrane Glycoproteins; D019014:fas Receptor; D003907:Dexamethasone; D007371:Interferon-gamma; D003513:Cycloheximide