1. ¹Department of Biochemistry and Molecular Biology, Universitat de València, E-46100 Burjassot, València, Spain
2. ²Apoptosis Section, Regulation of Cell Growth Laboratory, NCI, National Institutes of Health, Frederick, MD 21702, USA
3. ³Department of Medicinal Chemistry, Centro de Investigación Príncipe Felipe, E-46013 València, Spain
4. ⁴Department of Biological Organic Chemistry, IIQAB (CSIC), E-08034 Barcelona, Spain
5. ⁵Instituto de Biología Molecular y Celular, Universidad Miguel Hernández, 03202 Elx Alacant, Spain
6. ⁶Consejo Superior de Investigaciones Científicas (CSIC), E-46013 València, Spain

Correspondence: E Pérez-Payá, Centro de Investigación Príncipe Felipe and CSIC, Avda. Autopista del Saler, 16, E-46013 Valencia, Spain. Tel: +34-963289680; Fax: +34-963289701; E-mail: eperez@ochoa.fib.es

Received 27 May 2005; Revised 25 October 2005; Accepted 2 November 2005; Published online 9 December 2005.

Abstract

Apoptosis is a biological process relevant to human disease states that is strongly regulated through protein–protein complex formation. These complexes represent interesting points of chemical intervention for the development of molecules that could modulate cellular apoptosis. The apoptosome is a holoenzyme multiprotein complex formed by cytochrome c-activated Apaf-1 (apoptotic protease-activating factor), dATP and procaspase-9 that link mitochondria disfunction with activation of the effector caspases and in turn is of interest for the development of apoptotic modulators. In the present study we describe the identification of compounds that inhibit the apoptosome-mediated activation of procaspase-9 from the screening of a diversity-oriented chemical library. The active compounds rescued from the library were chemically optimised to obtain molecules that bind to both recombinant and human endogenous Apaf-1 in a cytochrome c-noncompetitive mechanism that inhibits the recruitment of procaspase-9 by the apoptosome. These newly identified Apaf-1 ligands decrease the apoptotic phenotype in mitochondrial-mediated models of cellular apoptosis.