title: Characterization of a sphingosine 1-phosphate receptor antagonist prodrug.
abstract: Sphingosine 1-phosphate (S1P) is a phospholipid that binds to a set of G protein-coupled receptors (S1P(1)-S1P(5)) to initiate an array of signaling cascades that affect cell survival, differentiation, proliferation, and migration. On a larger physiological scale, the effects of S1P on immune cell trafficking, vascular barrier integrity, angiogenesis, and heart rate have also been observed. An impetus for the characterization of S1P-initiated signaling effects came with the discovery that FTY720 [fingolimod; 2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol] modulates the immune system by acting as an agonist at S1P(1). In the course of structure-activity relationship studies to better understand the functional chemical space around FTY720, we discovered conformationally constrained FTY720 analogs that behave as S1P receptor type-selective antagonists. Here, we present a pharmacological profile of a lead S1P(1/3) antagonist prodrug, 1-(hydroxymethyl)-3-(3-octylphenyl)cyclobutane (VPC03090). VPC03090 is phosphorylated by sphingosine kinase 2 to form the competitive antagonist species 3-(3-octylphenyl)-1-(phosphonooxymethyl)cyclobutane (VPC03090-P) as observed in guanosine 5'-O-(3-[(35)S]thio)triphosphate binding assays, with effects on downstream S1P receptor signaling confirmed by Western blot and calcium mobilization assays. Oral dosing of VPC03090 results in an approximate 1:1 phosphorylated/alcohol species ratio with a half-life of 30 h in mice. Because aberrant S1P signaling has been implicated in carcinogenesis, we applied VPC03090 in an immunocompetent mouse mammary cancer model to assess its antineoplastic potential. Treatment with VPC03090 significantly inhibited the growth of 4T1 primary tumors in mice. This result calls to attention the value of S1P receptor antagonists as not only research tools but also potential therapeutic agents.
authors.affiliation: Department of Pharmacology, University of Virginia, Charlottesville, Virginia 22908-0735, USA.
authors.forename: Perry C
authors.initials: PC
authors.lastname: Kennedy
authors.forename: Ran
authors.initials: R
authors.lastname: Zhu
authors.forename: Tao
authors.initials: T
authors.lastname: Huang
authors.forename: Jose L
authors.initials: JL
authors.lastname: Tomsig
authors.forename: Thomas P
authors.initials: TP
authors.lastname: Mathews
authors.forename: Marion
authors.initials: M
authors.lastname: David
authors.forename: Olivier
authors.initials: O
authors.lastname: Peyruchaud
authors.forename: Timothy L
authors.initials: TL
authors.lastname: Macdonald
authors.forename: Kevin R
authors.initials: KR
authors.lastname: Lynch
mesh_terms: D000818:Animals; D001555:Benzene Derivatives / Q000493:pharmacokinetics / Q000494:pharmacology*; D015153:Blotting, Western; D016466:CHO Cells; D002118:Calcium / Q000378:metabolism; D002199:Capillary Permeability / Q000187:drug effects; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D003412:Cricetulus; D003503:Cyclobutanes / Q000493:pharmacokinetics / Q000494:pharmacology*; D005260:Female; D000068876:Fingolimod Hydrochloride; D016244:Guanosine 5'-O-(3-Thiotriphosphate) / Q000378:metabolism; D018655:Lymphocyte Count; D008231:Lymphopenia / Q000097:blood; D008325:Mammary Neoplasms, Experimental / Q000188:drug therapy / Q000473:pathology; D013058:Mass Spectrometry; D051379:Mice; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D011355:Prodrugs / Q000493:pharmacokinetics / Q000494:pharmacology*; D011409:Propylene Glycols / Q000493:pharmacokinetics / Q000494:pharmacology*; D011487:Protein Conformation; D011869:Radioligand Assay; D049349:Receptors, Lysosphingolipid / Q000037:antagonists & inhibitors*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000493:pharmacokinetics / Q000494:pharmacology; D013329:Structure-Activity Relationship
chemical_list: C562045:1-(hydroxymethyl)-3-(3-octylphenyl)cyclobutane; D001555:Benzene Derivatives; D003503:Cyclobutanes; D011355:Prodrugs; D011409:Propylene Glycols; D049349:Receptors, Lysosphingolipid; D016244:Guanosine 5'-O-(3-Thiotriphosphate); D000068876:Fingolimod Hydrochloride; D013110:Sphingosine; D002118:Calcium