We have previously demonstrated that the AR is also an immunological target antigen, recognized in patients with prostate cancer, and targetable by means of vaccines in rodent models with delays in prostate tumor growth.
Furthermore, ADT combined with vaccination, specifically a DNA vaccine encoding the ligand-binding domain of the AR, led to improved antitumor responses as measured by tumor volumes and delays in the emergence of castrate-resistant prostate tumors in two murine prostate cancer models (Myc-CaP and prostate-specific PTEN-deficient mice).
The dual roles of the AR in prostate epithelium and stroma may require us to reevaluate the target and timing of androgen-deprivation therapy for prostate cancer patients and may suggest a need to develop new drugs to selectively target stromal AR in the primary prostate tumors at earlier stages.
These results identify HoxB13 as a pivotal upstream regulator of AR-V7-driven transcriptomes that are often cell context-dependent in CRPC, suggesting that HoxB13 may serve as a therapeutic target for AR-V7-driven prostate tumors.
The highly tissue-specific expression profile, androgen regulation, chromosomal localization, and expression profile of AIbZIP in prostate tumors suggest that AIbZIP may play an important role in prostate cancer and in androgen receptor signaling in prostate cells.
Therefore, we searched for targets of the AR that may contribute to these anabolic processes and could be amenable to therapeutic intervention by virtue of differential expression in prostate tumours.
Ablation of AR function using antisense oligodeoxynucleotides, ribozymes or small interference RNAs (RNAi) holds promise as future approaches to the successful treatment of hormone-refractory, apoptosis-resistant prostate tumors.
Immunofluorescence data and western blot analyses determined that a lentivirus containing a 5'UTR derived from FGF-2 is the best candidate for directing selective gene expression in the prostate tumors of PTEN(-/-) mice in vivo.
The androgen receptor is implicated in mediating hormone-dependent prostate tumor growth, and androgen antagonists are effective in the treatment of these cancers.
Immunohistochemistry shows that LATS2 and AR are localized within the prostate epithelium and that LATS2 expression is lower in human prostate tumor samples than in normal prostate.
The results offer a mechanism-based therapeutic paradigm for disrupting the AR growth-promoting axis in the spectrum of prostate tumors while reducing global suppression of testosterone actions.
Therefore, decitabine-induced expression of cell growth controlling genes such as NKX3.1 or PMEPA1 underlines the clinical applicability of decitabine in prostate tumors harboring wild type androgen receptor.
This study is the first direct evidence that knockdown of AR is a viable therapeutic strategy for treatment of prostate tumors that have already progressed to the castration-resistant state.
In the absence of androgen, AR in androgen-dependent LNCaP cells was unstable with a degradation half-time (t(1/2)) of 3 h at 37 degrees C. In contrast, AR was 2-4 times more stable in recurrent CWR22 tumors (t(1/2), >12 h) and CWR-R1 or LNCaP-C4-2 cell lines (t(1/2), 6-7 h) derived from recurrent prostate tumors.
Our study links AR expression heterogeneity to distinct castration/enzalutamide responses and has important implications in understanding the cellular basis of prostate tumor responses to AR-targeting therapies and in facilitating development of novel therapeutics to target AR<sup>-/lo</sup> PCa cells/clones.