The G protein-coupled receptor GPR30 inhibits proliferation of estrogen receptor-positive breast cancer cells.
The G protein-coupled receptor GPR30 binds 17beta-estradiol (E(2)) yet differs from classic estrogen receptors (ERalpha and ERbeta). GPR30 can mediate E(2)-induced nongenomic signaling, but its role in ERalpha-positive breast cancer remains unclear. Gene expression microarray data from five cohorts comprising 1,250 breast carcinomas showed an association between increased GPR30 expression and ERalpha-positive status. We therefore examined GPR30 in estrogenic activities in ER-positive MCF-7 breast cancer cells using G-1 and diethylstilbestrol (DES), ligands that selectively activate GPR30 and ER, respectively, and small interfering RNAs. In expression studies, E(2) and DES, but not G-1, transiently downregulated both ER and GPR30, indicating that this was ER mediated. In Ca(2+) mobilization studies, GPR30, but not ERalpha, mediated E(2)-induced Ca(2+) responses because E(2), 4-hydroxytamoxifen (activates GPR30), and G-1, but not DES, elicited cytosolic Ca(2+) increases not only in MCF-7 cells but also in ER-negative SKBr3 cells. Additionally, in MCF-7 cells, GPR30 depletion blocked E(2)-induced and G-1-induced Ca(2+) mobilization, but ERalpha depletion did not. Interestingly, GPR30-coupled Ca(2+) responses were sustained and inositol triphosphate receptor mediated in ER-positive MCF-7 cells but transitory and ryanodine receptor mediated in ER-negative SKBr3 cells. Proliferation studies involving GPR30 depletion indicated that the role of GPR30 was to promote SKBr3 cell growth but reduce MCF-7 cell growth. Supporting this, G-1 profoundly inhibited MCF-7 cell growth, potentially via p53 and p21 induction. Further, flow cytometry showed that G-1 blocked MCF-7 cell cycle progression at the G(1) phase. Thus, GPR30 antagonizes growth of ERalpha-positive breast cancer and may represent a new target to combat this disease.
Ariazi
Eric A
EA
Fox Chase Cancer Center; Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Brailoiu
Eugen
E
Yerrum
Smitha
S
Shupp
Heather A
HA
Slifker
Michael J
MJ
Cunliffe
Heather E
HE
Black
Michael A
MA
Donato
Anne L
AL
Arterburn
Jeffrey B
JB
Oprea
Tudor I
TI
Prossnitz
Eric R
ER
Dun
Nae J
NJ
Jordan
V Craig
VC
D001943:Breast Neoplasms / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D002118:Calcium / Q000378:metabolism; D045744:Cell Line, Tumor; D049109:Cell Proliferation; D050759:Cyclin-Dependent Kinase Inhibitor p21 / Q000235:genetics / Q000378:metabolism; D003517:Cyclopentanes / Q000494:pharmacology; D004054:Diethylstilbestrol / Q000494:pharmacology; D004958:Estradiol / Q000494:pharmacology; D047628:Estrogen Receptor alpha / Q000235:genetics* / Q000378:metabolism; D004967:Estrogens / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D016193:G1 Phase / Q000187:drug effects; D015972:Gene Expression Regulation, Neoplastic / Q000187:drug effects; D006801:Humans; D015151:Immunoblotting; D011804:Quinolines / Q000494:pharmacology; D034622:RNA Interference; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism
C517943:1-(4-(6-bromobenzo(1,3)dioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta(c)quinolin-8-yl)ethanone; C493956:CDKN1A protein, human; D050759:Cyclin-Dependent Kinase Inhibitor p21; D003517:Cyclopentanes; D047628:Estrogen Receptor alpha; D004967:Estrogens; C109584:GPER1 protein, human; D011804:Quinolines; D011960:Receptors, Estrogen; D043562:Receptors, G-Protein-Coupled; D016159:Tumor Suppressor Protein p53; D004958:Estradiol; D004054:Diethylstilbestrol; D002118:Calcium