title: Phosphinophosphonates and Their Tris-pivaloyloxymethyl Prodrugs Reveal a Negatively Cooperative Butyrophilin Activation Mechanism.
abstract: Butyrophilin 3A1 (BTN3A1) binds small phosphorus-containing molecules, which initiates transmembrane signaling and activates butyrophilin-responsive cells. We synthesized several phosphinophosphonates and their corresponding tris-pivaloyloxymethyl (tris-POM) prodrugs and examined their effects on BTN3A1. An analog of (E)-4-hydroxy-3-methyl-but-2-enyl diphosphate (HMBPP) bound to BTN3A1 with intermediate affinity, which was enthalpy-driven. Docking studies revealed binding to the basic surface pocket and interactions between the allylic hydroxyl group and the BTN3A1 backbone. The phosphinophosphonate stimulated proliferation of Vγ9Vδ2 T cells with moderate activity (EC50= 26 μM). Cellular potency was enhanced >600-fold in the tris-POM prodrug (EC50= 0.041 μM). The novel prodrug also induced T cell mediated leukemia cell lysis. Analysis of dose-response data reveals HMBPP-induced Hill coefficients of 0.69 for target cell lysis and 0.68 in interferon secretion. Together, tris-POM prodrugs enhance the cellular activity of phosphinophosphonates, reveal structure-activity relationships of butyrophilin ligands, and support a negatively cooperative model of cellular butyrophilin activation.
authors.affiliation: Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: Rebekah R
authors.initials: RR
authors.lastname: Shippy
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Xiaochen
authors.initials: X
authors.lastname: Lin
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Sherry S
authors.initials: SS
authors.lastname: Agabiti
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Jin
authors.initials: J
authors.lastname: Li
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Brendan M
authors.initials: BM
authors.lastname: Zangari
authors.affiliation: Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Foust
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Michael M
authors.initials: MM
authors.lastname: Poe
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Chia-Hung Christine
authors.initials: CC
authors.lastname: Hsiao
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Olga
authors.initials: O
authors.lastname: Vinogradova
authors.affiliation: Department of Chemistry, University of Iowa , Iowa City, Iowa 52242, United States.
authors.forename: David F
authors.initials: DF
authors.lastname: Wiemer
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut , Storrs, Connecticut 06269, United States.|Institute for Systems Genomics, University of Connecticut , Storrs, Connecticut 06269, United States.
authors.forename: Andrew J
authors.identifier: 0000-0002-3029-1780
authors.initials: AJ
authors.lastname: Wiemer
mesh_terms: D015703:Antigens, CD / Q000378:metabolism*; D000071797:Butyrophilins / Q000819:agonists* / Q000378:metabolism*; D002460:Cell Line; D006801:Humans; D020014:K562 Cells; D008213:Lymphocyte Activation / Q000187:drug effects; D062105:Molecular Docking Simulation; D063065:Organophosphonates / Q000737:chemistry* / Q000494:pharmacology*; D010720:Phosphines / Q000737:chemistry / Q000494:pharmacology; D011355:Prodrugs / Q000737:chemistry* / Q000494:pharmacology*; D013601:T-Lymphocytes / Q000187:drug effects
chemical_list: D015703:Antigens, CD; C558381:BTN3A1 protein, human; D000071797:Butyrophilins; D063065:Organophosphonates; D010720:Phosphines; D011355:Prodrugs