The natural compound atraric acid suppresses androgen-regulated neo-angiogenesis of castration-resistant prostate cancer through angiopoeitin2

Castration-resistant prostate cancer (CRPC) is an incurable form of prostate cancer (PC) and a major therapeutic challenge. Here, we show that the natural compound, atraric acid (AA), inhibits besides the androgen receptor (AR) those AR-mutants that confer therapy resistance to AR-antagonists indicating a different mode of AR-antagonism. AA induces cellular senescence and inhibits intratumoral angiogenesis and CRPC tumour growth in treated xenograft mice. RNA-seq reveals an upregulated angiogenic transcriptional pathway by androgen. In line with this, conditioned medium from CRPC cells induces angiogenesis in two in vitro models using primary human endothelial cells. By employing immune arrays and mass-spec analyses, we found that androgens induced secretion of pro-angiogenic factors pinpointing to angiopoeitin2 (ANGPT2). The senescence-associated secretory phenotype revealed reduced ANGPT2 secretion by AA. Accordingly, immune-depletion of ANGPT2 or blocking ANGPT2-receptors inhibits angiogenesis. Our data propose AA as potential anti-PCa compound and ANGPT2 pathway as novel therapeutic target for CRPC. Overall design: Transcriptional profile of C-42 cells upon androgen treatment