title: Reduction of CTLL-2 cytotoxicity by induction of apoptosis with a Fas-estrogen receptor chimera.
abstract: Allogeneic bone marrow transplantation and donor lymphocyte infusion are powerful treatments for chemotherapy-resistant leukemia. Tumor eradication is attributed to a graft-versus-leukemia reaction by the donor-derived cytotoxic T lymphocytes (CTLs), but the same cell population may cause severe graft-versus-host disease. One strategy to suppress harmful CTL activity is to incorporate a suicide gene into the donor lymphocytes prior to infusion, and to destroy these cells when they aggressively attack nonmalignant host tissues. In this study, we investigated the feasibility of using a Fas-estrogen receptor fusion protein (MfasER) to control T cell-mediated cytotoxicity, based on our previous finding that the chimera transmits a Fas-mediated death signal through activation by estrogen binding. A murine CTL line CTLL-2 was transfected with a vector encoding MfasER, and the growth, viability and cytotoxic activity of the transfected cells (CTLL/MfasER) were analyzed. The expression of apoptosis-related proteins such as Fas ligand and perforin was also investigated. In the absence of estrogen, CTLL/MfasER showed similar growth to parental CTLL-2, and the killing activity was preserved. Addition of 10 (-7) M estrogen induced a rapid apoptosis of CTLL/MfasER, and the cytotoxicity was severely impaired. A decrease of Fas ligand and perforin in the estrogen-treated CTLL/MfasER was seen in an immunoblot analysis. These functional and biochemical analyses showed that the estrogen-inducible apoptosis in MfasER-expressing CTLs rapidly terminated their target cell killing. The feasibility of using the MfasER-estrogen system to control graft-versus-host disease was demonstrated.
authors.affiliation: Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical School, Tochigi 329-0498, Japan.
authors.forename: Minako
authors.initials: M
authors.lastname: Kametaka
authors.forename: Akihiro
authors.initials: A
authors.lastname: Kume
authors.forename: Takashi
authors.initials: T
authors.lastname: Okada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Mizukami
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Hanazono
authors.forename: Keiya
authors.initials: K
authors.lastname: Ozawa
mesh_terms: D000818:Animals; D017209:Apoptosis; D001483:Base Sequence; D002455:Cell Division; D002470:Cell Survival; D003602:Cytotoxicity, Immunologic / Q000502:physiology*; D017931:DNA Primers; D007700:Kinetics; D051379:Mice; D011960:Receptors, Estrogen / Q000235:genetics / Q000502:physiology*; D011993:Recombinant Fusion Proteins / Q000502:physiology; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology* / Q000502:physiology; D019014:fas Receptor / Q000235:genetics / Q000502:physiology*
chemical_list: D017931:DNA Primers; D011960:Receptors, Estrogen; D011993:Recombinant Fusion Proteins; D019014:fas Receptor