title: Calcium-sensing receptor modulates cell adhesion and migration via integrins.
abstract: The calcium-sensing receptor (CaSR) is a family C G protein-coupled receptor that is activated by elevated levels of extracellular divalent cations. The CaSR couples to members of the G(q) family of G proteins, and in the endocrine system this receptor is instrumental in regulating the release of parathyroid hormone from the parathyroid gland and calcitonin from thyroid cells. Here, we demonstrate that in medullary thyroid carcinoma cells, the CaSR promotes cellular adhesion and migration via coupling to members of the integrin family of extracellular matrix-binding proteins. Immunopurification and mass spectrometry, co-immunoprecipitation, and co-localization studies showed that the CaSR and β1-containing integrins are components of a macromolecular protein complex. In fibronectin-based cell adhesion and migration assays, the CaSR-positive allosteric modulator NPS R-568 induced a concentration-dependent increase in cell adhesion and migration; both of these effects were blocked by a specific CaSR-negative allosteric modulator. These effects were mediated by integrins because they were blocked by a peptide inhibitor of integrin binding to fibronectin and β1 knockdown experiments. An analysis of intracellular signaling pathways revealed a key role for CaSR-induced phospholipase C activation and the release of intracellular calcium. These results demonstrate for the first time that an ion-sensing G protein-coupled receptor functionally couples to the integrins and, in conjunction with intracellular calcium release, promotes cellular adhesion and migration in tumor cells. The significance of this interaction is further highlighted by studies implicating the CaSR in cancer metastasis, axonal growth, and stem cell attachment, functions that rely on integrin-mediated cell adhesion.
authors.affiliation: Department of Pharmaceutical Sciences, Leslie Dan Faculty of Pharmacy, University of Toronto, Toronto, Ontario M5S 3M2, Canada.
authors.forename: Sujeenthar
authors.initials: S
authors.lastname: Tharmalingam
authors.forename: Avais M
authors.initials: AM
authors.lastname: Daulat
authors.forename: Jordan E
authors.initials: JE
authors.lastname: Antflick
authors.forename: Syed M
authors.initials: SM
authors.lastname: Ahmed
authors.forename: Edward F
authors.initials: EF
authors.lastname: Nemeth
authors.forename: Stephane
authors.initials: S
authors.lastname: Angers
authors.forename: Arthur D
authors.initials: AD
authors.lastname: Conigrave
authors.forename: David R
authors.initials: DR
authors.lastname: Hampson
mesh_terms: D000494:Allosteric Regulation / Q000187:drug effects; D000814:Aniline Compounds / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D045744:Cell Line, Tumor; D002465:Cell Movement / Q000187:drug effects; D005353:Fibronectins / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D039641:Integrin beta Chains / Q000378:metabolism; D016023:Integrins / Q000378:metabolism*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology; D010627:Phenethylamines; D011437:Propylamines; D021381:Protein Transport / Q000187:drug effects; D051381:Rats; D044169:Receptors, Calcium-Sensing / Q000737:chemistry / Q000378:metabolism*; D015398:Signal Transduction / Q000187:drug effects
chemical_list: D000814:Aniline Compounds; D005353:Fibronectins; D039641:Integrin beta Chains; D016023:Integrins; C107873:N-(2-chlorophenylpropyl)-1-(3-methoxyphenyl)ethylamine; D009842:Oligopeptides; D010627:Phenethylamines; D011437:Propylamines; D044169:Receptors, Calcium-Sensing; C058161:glycyl-arginyl-glycyl-aspartyl-seryl-proline; D002118:Calcium