title: Evaluation of known and novel inhibitors of Orai1-mediated store operated Ca2+entry in MDA-MB-231 breast cancer cells using a Fluorescence Imaging Plate Reader assay.
abstract: The Orai1 Ca2+permeable ion channel is an important component of store operated Ca2+entry (SOCE) in cells. It's over-expression in basal molecular subtype breast cancers has been linked with poor prognosis, making it a potential target for drug development. We pharmacologically characterised a number of reported inhibitors of SOCE in MDA-MB-231 breast cancer cells using a convenient Fluorescence Imaging Plate Reader (FLIPR) assay, and show that the rank order of their potencies in this assay is the same as those reported in a wide range of published assays. The assay was also used in a screening project seeking novel inhibitors. Following a broad literature survey of classes of calcium channel inhibitors we used simplified ligand structures to query the ZINC on-line database, and following two iterations of refinement selected a novel Orai1-selective dichlorophenyltriazole hit compound. Analogues of this were synthesized and evaluated in the FLIPR assay to develop structure-activity relationships (SAR) for the three domains of the hit; triazole (head), dichlorophenyl (body) and substituted phenyl (tail). For this series, the results suggested the need for a lipophilic tail domain and an out-of-plane twist between the body and tail domains.
authors.affiliation: The School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia; Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia; Translational Research Institute, Brisbane, Queensland, Australia.
authors.forename: Iman
authors.initials: I
authors.lastname: Azimi
authors.affiliation: Auckland Cancer Society Research Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Jack U
authors.initials: JU
authors.lastname: Flanagan
authors.affiliation: Auckland Cancer Society Research Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand.
authors.forename: Ralph J
authors.initials: RJ
authors.lastname: Stevenson
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Queensland 4102, Australia.
authors.forename: Marco
authors.initials: M
authors.lastname: Inserra
authors.affiliation: Institute for Molecular Bioscience, The University of Queensland, St Lucia, Queensland 4072, Australia; School of Pharmacy, The University of Queensland, Woolloongabba, Queensland 4102, Australia.
authors.forename: Irina
authors.initials: I
authors.lastname: Vetter
authors.affiliation: The School of Pharmacy, The University of Queensland, Brisbane, Queensland, Australia; Mater Research Institute, The University of Queensland, Brisbane, Queensland, Australia; Translational Research Institute, Brisbane, Queensland, Australia.
authors.forename: Gregory R
authors.initials: GR
authors.lastname: Monteith
authors.affiliation: Auckland Cancer Society Research Centre, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand; Maurice Wilkins Centre for Molecular Biodiscovery, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand. Electronic address: b.denny@auckland.ac.nz.
authors.forename: William A
authors.initials: WA
authors.lastname: Denny
mesh_terms: D002121:Calcium Channel Blockers / Q000138:chemical synthesis / Q000494:pharmacology*; D045744:Cell Line, Tumor; D062126:Databases, Chemical; D004355:Drug Stability; D005453:Fluorescence; D057809:HEK293 Cells; D057166:High-Throughput Screening Assays; D006801:Humans; D000071740:ORAI1 Protein / Q000037:antagonists & inhibitors*; D013237:Stereoisomerism; D013329:Structure-Activity Relationship; D014230:Triazoles / Q000138:chemical synthesis / Q000494:pharmacology
chemical_list: D002121:Calcium Channel Blockers; D000071740:ORAI1 Protein; C510746:ORAI1 protein, human; D014230:Triazoles
keywords: Breast cancer; Calcium signalling; Orai1; Pharmacological inhibitors; Pharmacophore modelling; Store-operated calcium entry (SOCE)