title: CD95 ligand expression as a mechanism of immune escape in breast cancer.
abstract: Interaction of CD95 (Apo-1/Fas) and its ligand (CD95L) plays an important role in the regulation of the immune response, since CD95+ lymphocytes may be killed after engagement of the CD95 receptor. Studying the CD95/CD95L system in 40 cases of breast cancer, the malignant cells expressed CD95L, but lost CD95 expression, when compared with non-malignant mammary tissue. Jurkat T cells incubated on breast cancer sections underwent CD95L-specific apoptosis. The rate of apoptosis correlated with the CD95L mRNA levels of the tissue samples. In four breast cancer cell lines, CD95L expression was increased by interferon-gamma (IFN-gamma), which resulted in higher levels of CD95L-specific apoptosis in co-cultured Jurkat T cells. Since IFN-gamma is mainly secreted by activated T cells, up-regulation of CD95L in breast cancer cells in response to IFN-gamma may thus counterselect activated tumour-infiltrating T cells and favour the immune escape of breast cancer. As demonstrated by inhibition of matrix metalloproteinases, CD95L expressed on breast cancer cells can also be shed from the cell membrane into the culture supernatant. Supernatants derived from cultured breast cancer cells induced apoptosis in Jurkat T cells via CD95L. In breast cancer patients, depletion of CD4+ and CD8+ peripheral blood lymphocytes was significantly correlated with CD95L expression in the tumours. This might be suggestive for a relationship between CD95L expression by breast cancer and systemic immunosuppression.
authors.affiliation: Institut Pasteur, Department of Immunology, Unité de Biologie Moléculaire du Gène, Paris, France.
authors.forename: M
authors.initials: M
authors.lastname: Müschen
authors.forename: C
authors.initials: C
authors.lastname: Moers
authors.forename: U
authors.initials: U
authors.lastname: Warskulat
authors.forename: J
authors.initials: J
authors.lastname: Even
authors.forename: D
authors.initials: D
authors.lastname: Niederacher
authors.forename: M W
authors.initials: MW
authors.lastname: Beckmann
mesh_terms: D017209:Apoptosis; D001943:Breast Neoplasms / Q000276:immunology*; D015496:CD4-Positive T-Lymphocytes / Q000473:pathology; D018414:CD8-Positive T-Lymphocytes / Q000473:pathology; D004797:Enzyme-Linked Immunosorbent Assay; D053222:Fas Ligand Protein; D005260:Female; D005434:Flow Cytometry; D006801:Humans; D007150:Immunohistochemistry; D019169:Jurkat Cells; D018655:Lymphocyte Count; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D020033:Protein Isoforms / Q000276:immunology; D012333:RNA, Messenger / Q000032:analysis; D020133:Reverse Transcriptase Polymerase Chain Reaction; D019014:fas Receptor / Q000276:immunology*
chemical_list: C505661:FASLG protein, human; D053222:Fas Ligand Protein; D008562:Membrane Glycoproteins; D020033:Protein Isoforms; D012333:RNA, Messenger; D019014:fas Receptor