Received for publication February 5, 2008.
Revised March 7, 2008.
Accepted for publication March 10, 2008.

Potent, selective and cell penetrant inhibitors of SF-1 by functional uHTS

Abstract

The Steroidogenic factor 1 (SF-1, also known as NR5A1) is a transcription factor belonging to the nuclear receptor superfamily. Whereas most of the members of this family have been extensively characterized, the therapeutic potential and pharmacology of SF-1 still remains elusive. Described here is the identification and characterization of selective inhibitory chemical probes of SF-1 by a rational ultra-high-throughput screening (uHTS) strategy. A set of 64,908 compounds from the National Institute of Health's Molecular Libraries Small Molecule Repository (MLSMR) was screened in a transactivation cell-based assay employing a chimeric SF-1 construct. Two analogous isoquinolinones, SID7969543 and SID7970631, were identified as potent submicromolar inhibitors, yielding IC₅₀ values of 760 nM and 260 nM. The compounds retained their potency in a more physiologic functional assay employing the full-length SF-1 protein and its native response element, yielding IC₅₀ values of 30 and 16 nM, respectively. The selectivity of these isoquinolinones was confirmed via transactivation-based functional assays for RORA, VP-16 and LRH-1. Their cytotoxicity, solubility, permeability and metabolic stability were also measured. These isoquinolinones represent valuable chemical probes to investigate the therapeutic potential of SF-1.

Key words: Sex hormones, Transcriptional coactivators, Mutagenesis/Chimeric approaches, Transcription targets, Endocrine cells