A novel small molecule activator of nuclear receptor SHP inhibits HCC cell migration via suppressing Ccl2

Abstract

Small heterodimer partner (SHP, NR0B2) is a nuclear orphan receptor without endogenous ligands. Due to its crucial inhibitory role in liver cancer, it is of importance to identify small molecule agonists of SHP. As such, we initiated a probe discovery effort to identify compounds capable of modulating SHP function. First, we performed binding assays using small molecule microarrays (SMM) and discovered 5-(diethylsulfamoyl)-3-hydroxynaphthalene-2-carboxylic acid (DSHN) as a novel activator of SHP. DSHN transcriptionally activated Shp mRNA, but also stabilized the SHP protein by preventing its ubiquitination and degradation. Second, we identified Ccl2 as a new SHP target gene by RNA-seq. We showed that activation of SHP by DSHN repressed Ccl2 expression and secretion by inhibiting p65 activation of CCL2 promoter activity, as demonstrated in vivo in Shp-/- mice and in vitro in HCC cells with SHP overexpression and knockdown. Third, we elucidated a strong inhibitory effect of SHP and DSHN on HCC cell migration and invasion by antagonizing the effect of CCL2. Lastly, by interrogating a publicly available database to retrieve SHP expression profiles from multiple types of human cancers, we established a negative association of SHP expression with human cancer metastasis and patient survival. In summary, the discovery of a novel small molecule activator of SHP provides a therapeutic perspective for future translational and preclinical studies to inhibit HCC metastasis by blocking Ccl2 signaling.