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Signaling and secretion of chemotactic factors regulated by calcium‐sensing‐receptor mutants found in breast cancer patients
Author(s) -
Orduña Lennis Beatriz,
HidalgoMoyle Joseline Janai,
VázquezPrado José,
ReyesCruz Guadalupe
Publication year - 2017
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.31.1_supplement.614.31
Subject(s) - calcium sensing receptor , receptor , g protein coupled receptor , chemotaxis , secretion , microbiology and biotechnology , g protein , heterotrimeric g protein , biology , signal transduction , pertussis toxin , calcium , endocrinology , medicine , calcium metabolism , biochemistry
The calcium‐sensing‐receptor (CaSR) belonging to the class C of the GPCR family regulates cell proliferation, calcium homeostasis and secretion, among other processes, depending on the tissue in which this receptor is expressed. Its physiological importance is also evidenced by several disorders in the calcium homeostasis associated with a number of naturally mutations. The bioinformatic study of CaSR in the catalogue of somatic mutations in cancer (COSMIC) has documented 419 mutations of this receptor in patients with cancer. Sixteen of which are specifically found in breast cancer, four of them (CaSR N639K , CaSR T732A , CaSR R886Q and CaSR V894I ) were generated and study in our laboratory to analyze their role in the secretion of chemotactic factors and the signaling events. Considering the potential coupling of CaSR to multiple heterotrimeric G proteins, we examined the effect of PTX (pertussis toxin), an inhibitor of Gi protein; H89, a PKA inhibitor; and U73122, a phospholipase C inhibitor on ERK activation. Our results demonstrated that CaSR Wt signals through Gi and Gq proteins, however the mutants receptors were potentially linked to Gs as well as Gq, and the CaSR N639K could also activates Gi. Importantly, our results indicate that the mutant receptors promoted different patterns in the chemotactic factors secretion analyzed by the potential effect of conditioned media obtained from each mutant receptors to promote migration of porcine aortic endothelial cells (PAE) in Boyden chamber assays. The mutants CaSR T732A and CaSR V894I promoted the secretion of chemotactic factors in a calcium‐dependent manner comparable to the CaSR Wt although these secretion is minor with respect to the wild type receptor. The mutant CaSR N639K increased the secretion in a calcium‐independent manner, and its stimulation does not have an effect on secretion. Finally, the CaSR R886Q mutant receptor increase the secretion of chemotactic factors independently of stimulus, and surprisingly receptor stimulation inhibited the secretion of chemotactic factors. CONCLUSION The calcium sensing receptor mutants found in breast cancer patients potentially change the G‐protein coupling and elicited different secretory patterns, probably due to change in the G‐protein coupling. Support or Funding Information This work was supported by Consejo Nacional de Ciencia y Tecnologia (CONACyT) grants 240119 (to G.R.C.) and 152434 (to J.V.P.) and Fundación Miguel Aleman, A. C. (to G.R.C.). Lennis Beatriz Orduña Castillo is graduate student supported by a CONACyT fellowship (scholarship: 455391 )