title: Lack of FasL-mediated killing leads to in vivo tumor promotion in mouse Lewis lung cancer.
abstract: Lewis lung carcinoma (3LL) cells were constitutively resistant to Fas-mediated apoptosis, but overexpression of Fas on 3LL cells allowed Fas-mediated apoptosis after crosslinking with agonist anti-Fas antibody (Jo2) in vitro. Surprisingly, Fas-overexpressing 3LL cells showed enhanced in vivo tumor progression, whereas no promotion of in vivo tumor growth was observed for dominant negative (DN) Fas-overexpressing 3LL transfectants in which the cytoplasmic death domain was deleted. In addition, the promotion of in vivo tumor growth by Fas-overexpression was reduced in gld (FasL-mutation) mice compared to normal mice. These data indicate that intact Fas/FasL cell signaling is required for the promotion of in vivo tumor growth by Fas overexpression in 3LL cells. In contrast to the efficient Fas-mediated killing induced in vitro by crosslinking with anti-Fas antibody, Fas-overexpressing 3LL cells were resistant in vitro to Fas-mediated apoptosis by activated T cells or transient FasL transfection. These data suggest that agonist anti-Fas antibody and natural FasL can transmit qualitatively different signals, and crosslinking of Fas with natural FasL on 3LL cells does not deliver the expected death signal. Thus, our results demonstrate that in some cases overexpression of Fas can result in a survival advantage for tumor cells in vivo.
authors.affiliation: National Genome Research Institute, National Institute of Health, 5 Nokbun-dong, Eunpyung-ku, Seoul 122-701, Korea. cookie_jklee@hotmail.com
authors.forename: J-K
authors.initials: JK
authors.lastname: Lee
authors.forename: T J
authors.initials: TJ
authors.lastname: Sayers
authors.forename: T C
authors.initials: TC
authors.lastname: Back
authors.forename: J M
authors.initials: JM
authors.lastname: Wigginton
authors.forename: R H
authors.initials: RH
authors.lastname: Wiltrout
mesh_terms: D000818:Animals; D017209:Apoptosis; D018827:Carcinoma, Lewis Lung / Q000473:pathology*; D002455:Cell Division; D003432:Cross-Linking Reagents / Q000494:pharmacology; D003593:Cytoplasm / Q000378:metabolism; D004247:DNA / Q000378:metabolism; D018450:Disease Progression; D053222:Fas Ligand Protein; D005434:Flow Cytometry; D005822:Genetic Vectors; D007371:Interferon-gamma / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009154:Mutation; D009369:Neoplasms / Q000473:pathology; D017434:Protein Structure, Tertiary; D015398:Signal Transduction; D013601:T-Lymphocytes / Q000378:metabolism; D013997:Time Factors; D014162:Transfection; D015854:Up-Regulation
chemical_list: D003432:Cross-Linking Reagents; D053222:Fas Ligand Protein; C505658:Fasl protein, mouse; D008562:Membrane Glycoproteins; D007371:Interferon-gamma; D004247:DNA