title: Membrane-proximal TRAIL species are incapable of inducing short circuit apoptosis signaling: Implications for drug development and basic cytokine biology.
abstract: TRAIL continues to garner substantial interest as a recombinant cancer therapeutic while the native cytokine itself serves important tumor surveillance functions when expressed in membrane-anchored form on activated immune effector cells. We have recently developed the genetically stabilized TRAIL platform TR3 in efforts to improve the limitations associated with currently available drug variants. While in the process of characterizing mesothelin-targeted TR3 variants using a single chain antibody (scFv) delivery format (SS-TR3), we discovered that the membrane-tethered cytokine had a substantially increased activity profile compared to non-targeted TR3. However, cell death proceeded exclusively via a bystander mechanism and protected the mesothelin-positive targets from apoptosis rather than leading to their elimination. Incorporation of a spacer-into the mesothelin surface antigen or the cancer drug itself-converted SS-TR3 into a cis-acting phenotype. Further experiments with membrane-anchored TR3 variants and the native cytokine confirmed our hypothesis that membrane-proximal TRAIL species lack the capacity to physically engage their cognate receptors coexpressed on the same cell membrane. Our findings not only provide an explanation for the "peaceful" coexistence of ligand and receptor of a representative member of the TNF superfamily but give us vital clues for the design of activity-enhanced TR3-based cancer therapeutics.
authors.affiliation: Washington University School of Medicine, Department of Surgery, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Katharina
authors.initials: K
authors.lastname: Tatzel
authors.affiliation: Washington University School of Medicine, Division of Gynecologic Oncology, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Kuroki
authors.affiliation: Washington University School of Medicine, Department of Radiation Oncology, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Igor
authors.initials: I
authors.lastname: Dmitriev
authors.affiliation: Washington University School of Medicine, Department of Radiation Oncology, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Elena
authors.initials: E
authors.lastname: Kashentseva
authors.affiliation: Washington University School of Medicine, Department of Radiation Oncology, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: David T
authors.initials: DT
authors.lastname: Curiel
authors.affiliation: Washington University School of Medicine, Department of Surgery, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.|Alvin J. Siteman Cancer Center, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: S Peter
authors.initials: SP
authors.lastname: Goedegebuure
authors.affiliation: Washington University School of Medicine, Division of Gynecologic Oncology, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.|Alvin J. Siteman Cancer Center, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Powell
authors.affiliation: Washington University School of Medicine, Division of Gynecologic Oncology, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.|Alvin J. Siteman Cancer Center, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: David G
authors.initials: DG
authors.lastname: Mutch
authors.affiliation: Washington University School of Medicine, Department of Surgery, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.|Alvin J. Siteman Cancer Center, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: William G
authors.initials: WG
authors.lastname: Hawkins
authors.affiliation: Washington University School of Medicine, Department of Surgery, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.|Alvin J. Siteman Cancer Center, 660 S. Euclid Avenue, St. Louis, Missouri 63110, USA.
authors.forename: Dirk
authors.initials: D
authors.lastname: Spitzer
mesh_terms: D000818:Animals; D000912:Antibodies, Neoplasm / Q000494:pharmacology*; D017209:Apoptosis / Q000187:drug effects*; D016466:CHO Cells; D006224:Cricetinae; D003412:Cricetulus; D016207:Cytokines / Q000235:genetics / Q000378:metabolism; D004354:Drug Screening Assays, Antitumor / Q000379:methods; D057809:HEK293 Cells; D006801:Humans; D019169:Jurkat Cells; D000090204:Mesothelin; D051379:Mice; D009369:Neoplasms / Q000188:drug therapy / Q000235:genetics / Q000378:metabolism; D057127:Single-Chain Antibodies / Q000494:pharmacology*; D053221:TNF-Related Apoptosis-Inducing Ligand / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism
chemical_list: D000912:Antibodies, Neoplasm; D016207:Cytokines; C000715528:Msln protein, mouse; D057127:Single-Chain Antibodies; D053221:TNF-Related Apoptosis-Inducing Ligand; C505653:TNFSF10 protein, human; C505654:Tnfsf10 protein, mouse; D000090204:Mesothelin