Abstract
Sphingosine 1-phosphate (S1P) is a phospholipid that binds to a set of G protein-coupled receptors (S1P1–S1P5) 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 S1P1. 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 S1P1/3 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-[35S]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.
Footnotes
This work was supported by the National Institutes of Health National Institute of General Medical Sciences [Grants R01-GM067958 (to K.R.L. and T.L.M.), T32-GM008715 (to P.C.K.)]; an Abbott Laboratories research contract grant (to K.R.L.); and the Institut National de la Santé et de la Recherche Médicale and Comité Départemental de la Loire de la Ligue Nationale Contre le Cancer (M.D. and O.P.).
Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
doi:10.1124/jpet.111.181552.
↵ The online version of this article (available at http://jpet.aspetjournals.org) contains supplemental material.
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ABBREVIATIONS:
- S1P
- sphingosine 1-phosphate
- hS1P1
- human S1P1
- mS1P1
- mouse S1P1
- FTY720 (fingolimod)
- 2-amino-2-(2-[4-octylphenyl]ethyl)-1,3-propanediol
- FTY720-P
- 2-amino-2[2-(4-octylphenyl)ethyl]-1,3-propanediol,mono dihydrogen phosphate ester
- VPC03090
- 1-(hydroxymethyl)-3-(3-octylphenyl)cyclobutane
- VPC03090-P
- 3-(3-octylphenyl)-1-(phosphonooxymethyl)cyclobutane
- GTP[γ-35S]
- guanosine 5′-O-(3-[35S]thio)triphosphate
- SEW2871
- 5-[4-phenyl-5-(trifluoromethyl)-2-thienyl]-3-[3-(trifluoromethyl)phenyl]-1,2,4-oxadiazole
- VPC23019
- (R)-phosphoric acid mono-[2-amino-2-(3-octyl-phenylcarbamoyl)-ethyl] ester
- VPC44116
- (R)-3-amino-(3-octylphenylamino)-4-oxobutylphosphonic acid
- W146
- (R)-3-amino-(3-hexylphenylamino)-4-oxobutylphosphonic acid
- CHO
- Chinese hamster ovary
- GFP
- green fluorescent protein
- S1[33P]
- 33P-labeled sphingosine 1-phosphate
- CHAPS
- 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonic acid
- ERK
- extracellular signal-regulated kinase
- VPC03099
- 1-(hydroxymethyl)-3-(3-nonaphenyl)cyclobutane
- VPC03093
- 3-(3-heptylphenyl)-1-(phosphonooxymethyl)cyclobutane
- LC-MS
- liquid chromatography-mass spectrometry
- Emax
- maximal efficacy
- LPA
- lysophosphatidic acid
- VPC01091
- 1-[1-amino-3-(4-octylphenyl)cyclopentyl]methanol
- ANOVA
- analysis of variance
- TV
- tumor volume
- SAR
- structure-activity relationship
- PBS
- phosphate-buffered saline.
- Received March 13, 2011.
- Accepted May 31, 2011.
- Copyright © 2011 by The American Society for Pharmacology and Experimental Therapeutics
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