title: Growth of FasL-bearing tumor cells in syngeneic murine host induces apoptosis and toxicity in Fas(+) organs.
abstract: In the current study, we investigated whether the growth of FasL-bearing tumor cells would induce apoptosis and toxicity in organs that express high level of Fas. Sera from C57BL/6 +/+ (wild-type) mice injected with syngeneic FasL(+) tumors, LSA, or EL-4, showed significantly higher levels of soluble FasL than that from the nontumor-bearing mice. Furthermore, the soluble FasL was functional inasmuch as the sera from tumor-bearing mice were able to induce apoptosis in Fas(+) but not Fas(-) targets. Histopathologic studies and in situ TUNEL assay to detect apoptosis were carried out in C57BL/6 +/+ (Fas(+)) or C57BL/6 lpr/lpr (Fas(-)) mice injected with syngeneic LSA and EL-4 tumor cells. The morphology of the liver and thymus from tumor bearing C57BL/6 +/+ mice showed marked damage and tissue destruction. In contrast, the liver and thymus from tumor-bearing C57BL/6 lpr/lpr mice showed minimal damage. Furthermore, the tumor-bearing C57BL/6 +/+, but not the C57BL/6 lpr/lpr, mice exhibited significant apoptosis in the liver and thymus. The FasL responsible for toxicity was tumor derived rather than host derived; tumor-bearing C57BL/6 gld/gld (FasL-defective) mice also exhibited significant apoptosis in the liver and thymus. Together, these data suggested that the in vivo growth of FasL-bearing tumor cells can induce significant apoptosis and toxicity in Fas(+) tissues of the host. Such toxicity may be mediated by the soluble FasL produced by tumor cells. (Blood. 2000;95:2111-2117)
authors.affiliation: Department of Biology, Virginia-Maryland College of Veterinary Medicine, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061, USA.
authors.forename: A
authors.initials: A
authors.lastname: Zeytun
authors.forename: M
authors.initials: M
authors.lastname: Nagarkatti
authors.forename: P S
authors.initials: PS
authors.lastname: Nagarkatti
mesh_terms: D000818:Animals; D017209:Apoptosis; D019556:COS Cells; D002455:Cell Division / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D053222:Fas Ligand Protein; D005260:Female; D005434:Flow Cytometry; D020287:In Situ Nick-End Labeling; D008099:Liver / Q000473:pathology; D016399:Lymphoma, T-Cell / Q000276:immunology* / Q000473:pathology; D008562:Membrane Glycoproteins / Q000097:blood / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D019463:Mice, Inbred MRL lpr; D009368:Neoplasm Transplantation; D013950:Thymus Gland / Q000473:pathology; D014162:Transfection; D014407:Tumor Cells, Cultured
chemical_list: D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins