A novel function of CD40: induction of cell death in transformed cells.
CD40 is known as an important T-B cell interaction molecule which rescues B lymphocytes from undergoing apoptosis. Like other receptors of the tumor necrosis factor (TNF) receptor gene family, CD40 is expressed on cells of different tissue origins including some transformed cells. In contrast to its well-studied effects on B cells, the biological functions of CD40 in non-immune cells remain largely unknown. Here we show that CD40 ligation induces apoptotic cell death in transformed cells of mesenchymal and epithelial origin. This CD40-mediated cell death seems to use a preformed signaling pathway since it occurs even when protein synthesis is blocked. Notably, the CD40 cytoplasmic domain shares a structural homology with the recently defined "death domains" of the 55-kD TNF receptor (p55TNFR) and Fas. Despite these structural similarities, differences are seen in the way phorbol myristate acetate, interleukin 1, TNF, and various metabolic inhibitors influence the cellular responsiveness to CD40, p55TNFR, and Fas-mediated killing. Our study indicates that CD40 induces cell death by a distinct mechanism.
Hess
S
S
Institute for Immunology, University of Munich, Germany.
Engelmann
H
H
D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D017209:Apoptosis / Q000502:physiology*; D019013:CD40 Antigens / Q000378:metabolism*; D002471:Cell Transformation, Neoplastic; D002478:Cells, Cultured; D006224:Cricetinae; D004305:Dose-Response Relationship, Drug; D004357:Drug Synergism; D004847:Epithelial Cells; D004848:Epithelium / Q000502:physiology; D006131:Growth Inhibitors; D006801:Humans; D007375:Interleukin-1 / Q000494:pharmacology; D008648:Mesoderm / Q000166:cytology / Q000502:physiology; D051379:Mice; D018124:Receptors, Tumor Necrosis Factor / Q000378:metabolism; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D019014:fas Receptor / Q000276:immunology / Q000378:metabolism
D000906:Antibodies; D019013:CD40 Antigens; D006131:Growth Inhibitors; D007375:Interleukin-1; D018124:Receptors, Tumor Necrosis Factor; D014409:Tumor Necrosis Factor-alpha; D019014:fas Receptor; D013755:Tetradecanoylphorbol Acetate