Premium
Role of Fas and granule exocytosis pathways in tumor‐infiltrating T lymphocyte–induced apoptosis of autologous human lung‐carcinoma cells
Author(s) -
Dorothee Guillaume,
Ameyar Maya,
Bettaieb Ali,
Verg Isabelle,
Echchakir Hamid,
Bouziane Mohammed,
Chouaib Salem,
MamiChouaib Fathia
Publication year - 2001
Publication title -
international journal of cancer
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.475
H-Index - 234
eISSN - 1097-0215
pISSN - 0020-7136
DOI - 10.1002/1097-0215(200002)9999:9999<::aid-ijc1132>3.0.co;2-v
Subject(s) - biology , granzyme b , fas receptor , cytotoxic t cell , granzyme , fas ligand , transfection , apoptosis , microbiology and biotechnology , ctl* , perforin , cancer research , programmed cell death , cell culture , immunology , immune system , t cell , in vitro , biochemistry , genetics
We have isolated a cytotoxic T lymphocyte (CTL) clone, Heu161, that reacts specifically with the human autologous lung carcinoma cell line IGR‐Heu. We first demonstrated that IGR‐Heu lacked Fas‐receptor expression and was resistant to CD95‐induced apoptosis. To further elucidate the role of Fas in tumor immune surveillance, we have stably transfected IGR‐Heu with a Fas‐expression vector and isolated CD95‐sensitive and ‐resistant clones. Our data indicated that the resistance of 2 selected Fas‐transfected clones to CD95‐mediated lysis correlated with down‐regulation of caspase‐8 or its lack of cleavage and subsequent activation. All Fas transfectants, either sensitive or resistant to anti‐Fas agonistic antibody, were as efficiently lysed by the CTL clone as the parental cell line. In addition, neither anti‐Fas‐blocking antibody nor Fas‐Fc molecule inhibited T‐cell lysis of Fas‐sensitive tumor clone. This cytotoxicity was extracellular Ca 2+ ‐dependent and abolished in the presence of EGTA, indicating that it was mainly granzyme‐mediated. Interestingly, although the caspase inhibitor z‐VAD‐fmk had no effect on tumor‐cell lysis, it efficiently blocked target DNA damage triggered by autologous CTLs via the granule exocytosis pathway, indicating that the latter event was caspase‐dependent. The present results suggest that lung carcinoma‐specific CTLs use mainly a granule exocytosis‐dependent pathway to lyse autologous target cells and that these effectors are able to circumvent alteration of the Fas‐triggered intracellular signalling pathway via activation of a caspase‐independent cytoplasmic death mechanism. © 2001 Wiley‐Liss, Inc.