title: A Screening Assay Cascade to Identify and Characterize Novel Selective Estrogen Receptor Downregulators (SERDs).
abstract: Here, we describe an approach to identify novel selective estrogen receptor downregulator (SERD) compounds with improved properties such as oral bioavailability and the potential of increased efficacy compared to currently marketed drug treatments. Previously, methodologies such as Western blotting and transient cell reporter assays have been used to identify and characterize SERD compounds, but such approaches can be limited due to low throughput and sensitivity, respectively. We have used an endogenous cell-imaging strategy that has both the throughput and sensitivity to support a large-scale hit-to-lead program to identify novel compounds. A screening cascade with a suite of assays has been developed to characterize compounds that modulate estrogen receptor α (ERα)-mediated signaling or downregulate ERα levels in cells. Initially, from a focused high-throughput screening, novel ERα binders were identified that could be modified chemically into ERα downregulators. Following this, cellular assays helped determine the mechanism of action of compounds to distinguish between on-target and off-target compounds and differentiate SERDs, selective estrogen receptor modulator (SERM) compounds, and agonist ERα ligands. Data are shown to exemplify the characterization of ERα-mediated signaling inhibitors using a selection of literature compounds and illustrate how this cascade has been used to drive the chemical design of novel SERD compounds.
authors: Discovery Sciences, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Rowena
authors: R
authors: Callis
authors: Oncology Innovative Medicines Unit, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Alfred
authors: A
authors: Rabow
authors: Discovery Sciences, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Michael
authors: M
authors: Tonge
authors: Oncology Innovative Medicines Unit, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Robert
authors: R
authors: Bradbury
authors: Discovery Sciences, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Mairi
authors: M
authors: Challinor
authors: Discovery Sciences, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Karen
authors: K
authors: Roberts
authors: Discovery Sciences, AstraZeneca, Macclesfield, Cheshire, UK.
authors: Karen
authors: K
authors: Jones
authors: Discovery Sciences, AstraZeneca, Macclesfield, Cheshire, UK rowena.callis@astrazeneca.com graeme.walker@astrazeneca.com.
authors: Graeme
authors: G
authors: Walker
mesh_terms: D045744:Cell Line, Tumor; D049109:Cell Proliferation; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation; D055808:Drug Discovery / Q000379:methods*; D004353:Drug Evaluation, Preclinical / Q000379:methods*; D047628:Estrogen Receptor alpha / Q000037:antagonists & inhibitors / Q000378:metabolism; D057166:High-Throughput Screening Assays; D006801:Humans; D011485:Protein Binding; D011960:Receptors, Estrogen / Q000037:antagonists & inhibitors* / Q000378:metabolism*; D011980:Receptors, Progesterone / Q000378:metabolism; D020845:Selective Estrogen Receptor Modulators / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects*; D054852:Small Molecule Libraries
chemical_list: D047628:Estrogen Receptor alpha; D011960:Receptors, Estrogen; D011980:Receptors, Progesterone; D020845:Selective Estrogen Receptor Modulators; D054852:Small Molecule Libraries
keywords: SERD; cell-based assays; estrogen receptor; screening cascade