Whereas AR copy number was unchanged from before treatment to progression and no mutant AR alleles showed signal for acquired gain, we observed emergence of T878A or L702H AR amino acid changes in 13% of tumors at progression on abiraterone.
PET/CT imaging and biodistribution studies revealed a significantly higher uptake of (18) F-RB390 in T877A mutation positive xenografts compared to PC-3 control tumors.This effect was blunted with DHT.
In extending the analysis of our multi-ligand complexes of the mutant T877A-AR we observed significant enrichment of specific complexes between normal and primary prostatic tumors, which were furthermore correlated with known clinical outcomes.
In prostate cancer model transgenic mice, the onset of prostatic tumorigenesis as well as tumor growth was significantly potentiated by introduction of the AR T877A mutation into the prostate.
Furthermore, results from additional correlative gene microarray analysis studies of all three AR isoform (WT, T877A, 0CAG) subnetwork clusters were assessed and found to be significantly enriched in tumor versus normal prostate tissues.
We have shown previously that a known xenoestrogen, bisphenol A (BPA), activates a tumor-derived AR mutant (T877A), leading to androgen-independent prostate cancer cell proliferation.