Selection of a GPER1 Ligand via Ligand-based Virtual Screening Coupled to Molecular Dynamics Simulations and Its Anti-proliferative Effects on Breast Cancer Cells

Abstract

Recent reports have demonstrated the role of the G protein-coupled estrogen receptor (GPER1) on the growth and proliferation of breast cancer cells. The coupling of GPER1 to estrogen, tamoxifen or fulvestrant triggers cellular signaling pathways (PI3K and ERK) related to cell proliferation. In an effort to develop new therapeutic strategies against breast cancer, we performed an in silico study to explore the binding pose of a set of designed G15 and G1 analogue compounds, including phenol red. First, we included a carboxyl group instead of the acetyl group from G1 to form amides with several moieties to increase the affinity for GPER1. Then, all the target compounds were submitted to an in silico ADMET study. Then, the ligands were coupled to GPER1 using ligand-based virtual screening to finally achieve molecular dynamics simulations of the best molecule on GPER1, as well as of phenol red, to explore its recognition properties. According to the in silico ADMET and docking studies, the best molecule was named G1-PABA ((3aS,4R,9bR)-4-(6-bromobenzo[d][1,3]dioxol-5-yl)-3a,4,5,9b-tetrahydro-3H-cyclopenta[c]quinoline-8-carboxylic acid). It was synthesized and assayed in vitro in breast cancer (MCF-7 and MDA-MB-231) and normal (MCF-10A) cell lines. Experimental assays showed that the target compound was able to decrease cell proliferation, showing IC50 values of 15.93 µM, 52.92 µM and 32.45 µM in the MCF-7, MDA-MB-231 and MCF-10A cell lines, respectively, after 72 h of treatment. Interestingly, the target compound showed better IC50 values without phenol red, suggesting that phenol red could interfere with the G1-PABA action at GPER, which is present in MCF-7 cells according to PCR studies and explains the cell proliferation effects. In conclusion, a concentration-dependent inhibition of cell proliferation occurred with G1-PABA in the assayed cell lines and could be due to its action on GPER1.

Chronic GPER1 Activation Protects Against Oxidative Stress-Induced Cardiomyoblast Death via Preservation of Mitochondrial Integrity and Deactivation of Mammalian Sterile-20-Like Kinase/Yes-Associated Protein Pathway

“…GPER1 activation is now well-known for inducing protective effects in several disease models, including I/R injury, hypertension (4-6), Parkinson's disease (23), retinal ganglion degeneration (74), and breast cancer (75). In fact, GPER1 activation has been reported to exert protective effects against harmful effects in several other organs, including the heart (4-6), brain (21,76), muscle (77), testes (77), intestine (26), and kidney (78).…”

Computational Approaches for the Discovery of GPER Targeting Compounds

“…A number of additional GPER binders have also been identified using theoretical modeling calculations. It is the case of G1-PABA ( 54 ), a compound part of a small series of G1 analogs, in which the acetyl moiety is replaced with a carboxyl group. The same pharmacophore core was further used to obtain a G1-PABA methylester and L -proline derivative, with similar structural and energetic binding properties ( 55 ).…”

Modifications on the Tetrahydroquinoline Scaffold Targeting a Phenylalanine Cluster on GPER as Antiproliferative Compounds against Renal, Liver and Pancreatic Cancer Cells

“…G1-PABA ( 1 ) and the tert-butyl derivative (compound 7 ) were obtained following the previous method reported by our research group [ 22 , 23 ].…”

“…Thus, we started with a G1 analog previously prepared by our research group [ 22 ], which is subsequently referred to as G1-PABA. The chemical synthesis of G1-PABA involved modification of the p -amino acetophenone of G1 using p -aminobenzoic acid, which has shown inhibitory activity against breast cancer cells [ 22 , 23 ]. Once G1-PABA was synthetized, compounds 4 , 5 and 7 were synthesized and tested in renal, liver and pancreatic cancer cells.…”