1. Academic Validation
  2. Heterodimeric GW7604 Derivatives: Modification of the Pharmacological Profile by Additional Interactions at the Coactivator Binding Site

Heterodimeric GW7604 Derivatives: Modification of the Pharmacological Profile by Additional Interactions at the Coactivator Binding Site

  • J Med Chem. 2021 May 13;64(9):5766-5786. doi: 10.1021/acs.jmedchem.0c02230.
Alexandra K Knox 1 Christina Kalchschmid 1 Daniela Schuster 1 2 Francesca Gaggia 1 Ronald Gust 1
Affiliations

Affiliations

  • 1 Department of Pharmaceutical Chemistry, Institute of Pharmacy, CMBI - Center for Molecular Biosciences Innsbruck, University of Innsbruck, CCB - Center for Chemistry and Biomedicine, 6020 Innsbruck, Austria.
  • 2 Department of Pharmaceutical and Medicinal Chemistry, Institute of Pharmacy, Paracelsus Medical University, 5020 Salzburg, Austria.
Abstract

(E/Z)-3-(4-((E)-1-(4-Hydroxyphenyl)-2-phenylbut-1-enyl)phenyl)acrylic acid (GW7604) as a derivative of (Z)-4-hydroxytamoxifen (4-OHT) was linked by diaminoalkane spacers to molecules that are known Binders to the coactivator binding site (benzimidazole or thioxo-quinazolinone scaffolds). With this modification, an optimization of the pharmacological profile was achieved. The most active thioxo-quinazolinone derivative 16 showed extraordinarily high affinity to the Estrogen receptor (ER) β (RBA = 110%), inhibited effectively the coactivator recruitment (IC50 = 20.88 nM (ERα) and 28.34 nM (ERβ)), acted as a pure estradiol (E2) antagonist in a transactivation assay (IC50 = 18.5 nM (ERα) and 7.5 nM (ERβ)), and downregulated the ERα content in MCF-7 cells with an efficacy of 60% at 1 μM. The cytotoxicity was restricted to hormone-dependent MCF-7 (IC50 = 4.2 nM) and tamoxifen-resistant MCF-7TamR cells (IC50 = 476.6 nM). The compounds bearing a thioxo-quinazolinone moiety can therefore be assigned as pure E2-antagonistic selective ER degraders/downregulators. By contrast, the benzimidazole derivatives acted solely as pure antagonists without degradation of the ER.

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