title: Biochemical regulation of breast cancer cell expression of S1P2 (Edg-5) and S1P3 (Edg-3) G protein-coupled receptors for sphingosine 1-phosphate.
abstract: G protein-coupled receptors (GPCRs) for lysophosphatidic acid (LPA) and sphingosine 1-phosphate (S1P) transduce signals to many functions of normal cells. Most human cancer cells upregulate S1P and LPA GPCRs, in patterns distinctive for each type of tumor. The findings that 1-alpha, 25-dihydroxy-vitamin D(3) (VD3) and all-trans retinoic acid (RA) differentially alter expression of the predominant S1P(3) (Edg-3) R and S1P(2) (Edg-5) R in human breast cancer cells (BCCs) permitted analyses of their individual activities, despite a lack of selective pharmacological probes. S1P-evoked increases in [Ca(2+)](i) in S1P(3) R-predominant BCCs were suppressed by concentrations of VD3 and RA which decreased expression of S1P(3) Rs, despite RA-induced increases in S1P(2) Rs. S1P-elicited chemokinetic migration of S1P(3) R-predominant BCCs across a type IV collagen-coated micropore filter also was inhibited by concentrations of VD3 and RA which decreased expression of S1P(3) Rs. The RA-induced increase in expression of S1P(2) Rs did not prevent suppression by RA of S1P-elicited chemokinesis, which appears to be mediated by S1P(3) Rs, but instead exposed S1P(2) R-mediated inhibition of epidermal growth factor-stimulated chemotaxis of BCCs. In contrast, expression of the predominant LPA(2) Rs, LPA-evoked increase in [Ca(2+)](i) and LPA-stimulated chemokinetic migration were suppressed concomitantly by RA but not VD3. Thus two structurally-homologous S1P Rs of BCCs differ in coupling to [Ca(2+)](i) signaling and have opposite effects on protein growth factor-stimulated chemotaxis.
authors.affiliation: Department of Medicine, University of California, San Francisco, CA 94143-0711, USA.
authors.forename: Hana
authors.initials: H
authors.lastname: Dolezalova
authors.forename: Geetha
authors.initials: G
authors.lastname: Shankar
authors.forename: Mei-Chuan
authors.initials: MC
authors.lastname: Huang
authors.forename: Daniel D
authors.initials: DD
authors.lastname: Bikle
authors.forename: Edward J
authors.initials: EJ
authors.lastname: Goetzl
mesh_terms: D001943:Breast Neoplasms / Q000378:metabolism*; D002117:Calcitriol / Q000494:pharmacology; D002118:Calcium / Q000032:analysis / Q000378:metabolism; D002465:Cell Movement / Q000187:drug effects; D002478:Cells, Cultured; D002633:Chemotaxis; D004815:Epidermal Growth Factor / Q000494:pharmacology; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D008246:Lysophospholipids; D008297:Male; D008565:Membrane Proteins / Q000032:analysis / Q000096:biosynthesis; D011956:Receptors, Cell Surface / Q000032:analysis / Q000096:biosynthesis / Q000187:drug effects / Q000378:metabolism*; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D049312:Receptors, Lysophospholipid; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism* / Q000494:pharmacology; D014212:Tretinoin / Q000494:pharmacology
chemical_list: C092794:GPR3 protein, human; D008246:Lysophospholipids; D008565:Membrane Proteins; D011956:Receptors, Cell Surface; D043562:Receptors, G-Protein-Coupled; D049368:Receptors, Lysophosphatidic Acid; D049312:Receptors, Lysophospholipid; C060506:sphingosine 1-phosphate; D014212:Tretinoin; D004815:Epidermal Growth Factor; D002117:Calcitriol; D013110:Sphingosine; D002118:Calcium