GSE172205
The natural compound atraric acid suppresses androgen-regulated neo-angiogenesis of castration-resistant prostate cancer through angiopoietin 2
Castration-resistant prostate cancer (CRPC) is an aggressive lethal form of prostate cancer (PCa), which presents a major therapeutic challenge. Here, we show that the natural compound, atraric acid (AA), inhibits not only the androgen receptor (AR) but also targets those AR-mutants that confer therapy resistance to other clinically used AR-antagonists indicating a different mode of AR-antagonism. AA induces cellular senescence in CRPC and inhibits CRPC tumour growth in vivo xenograft model. The secretome of CRPC cells induces androgen-dependent angiogenesis, which is counteracted by AA regulated senescence-associated secretory phenotype (SASP) in two in vitro models using primary human endothelial cells. In line with this, in tumours, vessel number is decreased in the mouse group treated with AA suggesting the repression of intratumoural neo-angiogenesis by AA. Transcriptome sequencing and mass spec analysis of the secretome revealed upregulated angiogenic pathways by androgen, however, being VEGF-independent and pointing to the secretion of the pro-angiogenic factor angiopoietin 2 (ANGPT2) induced by androgens and repressed by AA as a key driver of neo-angiogenesis. In agreement with this, AA treatment of native patient-derived PCa tumour samples ex vivo inhibits ANGPT2 expression. Mechanistically, besides AA, immune-depletion of ANGPT2 or blocking ANGPT2-receptors inhibits androgen-induced angiogenesis. Taken together, we reveal a VEGF-independent ANGPT2 pathway targeted by AA to inhibit androgen-regulated neo-angiogenesis. Overall design: Transcriptional profile of C4-2 cells treated with androgen receptor ligands