Identification of HOXB13 binding sites in metastatic PC treated with Enzalutamide

HOXB13 is a developmentally regulated transcription factor, co-expressed along with the Androgen receptor (AR) in a majority of PCs. Previous studies have indicated context dependent roles of HOXB13 in the functional regulation of AR and enrichment of HOXB13 motifs in the AR cistrome. Our studies showed that genetic or pharmacological blockade of HOXB13 sensitized mCRPCs to Enzalutamide (ENZ, Xtandi), an anti-androgen that is currently deployed to treat mCRPC patients. To identify HOXB13-mediated mechanism of castration-resistance ChIP-sequencing was performed with the HOXB13-K13ac, or IgG antibodies in the metastatic prostate cancer cell line, C4-2B in vehicle treated as well as Enzalutamide treated cell lines. We demonstrated for the first time that BRD4, epigenetically regulates HOXB13 gene expression in PCs. Consistently, JQ1 the prototype BET inhibitor suppresses HOXB13 expression and inhibit mCRPC growth. ChIP-sequence analysis reveals that HOXB13 recruitment to the chromatin is not completely abrogated in Enzalutamide treated cells identify a subset of genes that may have potential role in CRPC proliferation, anti-androgen resistance and metastasis. Six samples were analyzed. These samples included Vehicle control for the inhibitor treatments and IgG for antibody control. treaan be targeted with MA4--022-1