Combining hit identification strategies: fragment-based and in silico approaches to orally active 2-aminothieno[2,3-d]pyrimidine inhibitors of the Hsp90 molecular chaperone

  • J Med Chem. 2009 Aug 13;52(15):4794-809. doi: 10.1021/jm900357y.
Paul A Brough  1 ,  Xavier Barril ,  Jenifer Borgognoni ,  Patrick Chene ,  Nicholas G M Davies ,  Ben Davis ,  Martin J Drysdale ,  Brian Dymock ,  Suzanne A Eccles ,  Carlos Garcia-Echeverria ,  Christophe Fromont ,  Angela Hayes ,  Roderick E Hubbard ,  Allan M Jordan ,  Michael Rugaard Jensen ,  Andrew Massey ,  Angela Merrett ,  Antony Padfield ,  Rachel Parsons ,  Thomas Radimerski ,  Florence I Raynaud ,  Alan Robertson ,  Stephen D Roughley ,  Joseph Schoepfer ,  Heather Simmonite ,  Swee Y Sharp ,  Allan Surgenor ,  Melanie Valenti ,  Steven Walls ,  Paul Webb ,  Mike Wood ,  Paul Workman ,  Lisa Wright
Affiliations
  • 1. Vernalis Ltd., Granta Park, Great Abington, Cambridge CB21 6GB, UK. [email protected]
Abstract

Inhibitors of the HSP90 molecular chaperone are showing considerable promise as potential molecular therapeutic agents for the treatment of Cancer. Here we describe novel 2-aminothieno[2,3-d]pyrimidine ATP competitive HSP90 inhibitors, which were designed by combining structural elements of distinct low affinity hits generated from fragment-based and in silico screening exercises in concert with structural information from X-ray protein crystallography. Examples from this series have high affinity (IC50 = 50-100 nM) for HSP90 as measured in a fluorescence polarization (FP) competitive binding assay and are active in human Cancer cell lines where they inhibit cell proliferation and exhibit a characteristic profile of depletion of oncogenic proteins and concomitant elevation of Hsp72. Several examples (34a, 34d and 34i) caused tumor growth regression at well tolerated doses when administered orally in a human BT474 human Breast Cancer xenograft model.