Discovery of 22(S)-23-phenyl-24-norchol-5-en-3β,22-diol (PFM046) as the first-in-class, steroidal, non-sulfated Liver X Receptor antagonist with anticancer activity

Abstract

A plethora of studies have demonstrated the crucial role played by Liver X Receptors (LXRs) in cancer. However, whether LXRs activation results in pro-versus anti-tumor effects is still matter of debate. Recently, we have reported the ability of 22(S)-hydroxycholesterol-3-sulfate (PFM037) to antagonize LXRα activity, and, at the same time, its capability to improve in-vivo anti-tumor immune responses. Herein we report the first study aimed at the definition of structure-activity relationships of PFM037. Successfully, we identified 22(S)-23-phenyl-24-norchol-5-en-3β,22-diol (PFM046) as a more potent LXRs antagonist than PFM037. PFM046 showed a peculiar LXR target gene expression profile, being able, as expected for an antagonist, to suppress SCD1 and FASN expression, while surprisingly maintaining the ability to upregulate ABCA1 gene, as typical for an agonist. PFM046 showed a remarkable antitumor activity in two both in vitro-and in-vivo mouse models, highlighting the high potential of LXRs antagonists in oncological applications.

Keywords: Anticancer agents; LXR antagonist; Oxysterol derivatives; Semi-synthesis of steroids.