DrugCentral is a public resource (http://drugcentral.org) that serves the scientific community by providing up-to-date drug information, as described in previous papers. The current release includes 109 newly approved (October 2018 through March 2020) active pharmaceutical ingredients in the US, Europe, Japan and other countries; and two molecular entities (e.g. mefuparib) of interest for COVID19. New additions include a set of pharmacokinetic properties for ∼1000 drugs, and a sex-based separation of side effects, processed from FAERS (FDA Adverse Event Reporting System); as well as a drug repositioning prioritization scheme based on the market availability and intellectual property rights forFDA approved drugs. In the context of the COVID19 pandemic, we also incorporated REDIAL-2020, a machine learning platform that estimates anti-SARS-CoV-2 activities, as well as the ‘drugs in news’ feature offers a brief enumeration of the most interesting drugs at the present moment. The full database dump and data files are available for download from the DrugCentral web portal.

Between 2004 and 2008, the NIH molecular libraries and imaging initiative (MLI) pilot phase funded ten high-throughput Screening Centers, resulting in the deposition of 691 assays into PubChem and the nomination of 64 chemical probes. We crowdsourced the MLI output to 11 experts, who expressed medium or high levels of confidence in 48 of these 64 probes.

Bazedoxifene (BZA) is a third-generation selective estrogen receptor modulator (SERM) that has been approved for the prevention and treatment of postmenopausal osteoporosis. It has antitumor activity; however, its mechanism of action remains unclear. In the present study, we characterized the effects of BZA and several other SERMs on the proliferation of hormone-dependent MCF-7 and T47D breast cancer cells and hormone-independent MCF-7:5C and MCF-7:2A cells and examined its mechanism of action in these cells. We found that all of the SERMs inhibited the growth of MCF-7, T47D, and MCF-7:2A cells; however, only BZA and fulvestrant (FUL) inhibited the growth of hormone-independent MCF-7:5C cells. Cell cycle analysis revealed that BZA and FUL induced G 1 blockade in MCF-7:5C cells; however, BZA down-regulated cyclin D1, which was constitutively overexpressed in these cells, whereas FUL suppressed cyclin A. Further analysis revealed that small interfering RNA knockdown of cyclin D1 reduced the basal growth of MCF-7:5C cells, and it blocked the ability of BZA to induce G 1 arrest in these cells. BZA also down-regulated estrogen receptor-␣ (ER␣) protein by increasing its degradation and suppressing cyclin D1 promoter activity in MCF-7:5C cells. Finally, molecular modeling studies demonstrated that BZA bound to ER␣ in an orientation similar to raloxifene; however, a number of residues adopted different conformations in the induced-fit docking poses compared with the experimental structure of ER␣-raloxifene. Together, these findings indicate that BZA is distinct from other SERMs in its ability to inhibit hormone-independent breast cancer cell growth and to regulate ER␣ and cyclin D1 expression in resistant cells.

Background and Purpose Oestrogen receptor alpha (ERα) binds to different ligand which can function as complete/partial oestrogen‐agonist or antagonist. This depends on the chemical structure of the ligands which modulates the transcriptional activity of the oestrogen‐responsive genes by altering the conformation of the liganded‐ERα complex. This study determined the molecular mechanism of oestrogen‐agonistic/antagonistic action of structurally similar ligands, bisphenol (BP) and bisphenol A (BPA) on cell proliferation and apoptosis of ERα + ve breast cancer cells. Experimental Approach DNA was measured to assess the proliferation and apoptosis of breast cancer cells. RT‐PCR and ChIP assays were performed to quantify the transcripts of TFF1 gene and recruitment of ERα and SRC3 at the promoter of TFF1 gene respectively. Molecular docking was used to delineate the binding modes of BP and BPA with the ERα. PCR‐based arrays were used to study the regulation of the apoptotic genes. Key Results BP and BPA induced the proliferation of breast cancer cells; however, unlike BPA, BP failed to induce apoptosis. BPA consistently acted as an agonist in our studies but BP exhibited mixed agonistic/antagonistic properties. Molecular docking revealed agonistic and antagonistic mode of binding for BPA and BP respectively. BPA treatment resembled E2 treatment in terms of PCR‐based regulation of apoptotic genes whereas BP was similar to 4OHT treatment. Conclusions and Implications The chemical structure of ERα ligand determines the agonistic or antagonistic biological responses by the virtue of their binding mode, conformation of the liganded‐ERα complex and the context of the cellular function.