1-7-bis(4-hydroxy-3-methoxyphenyl)-1-4-6-heptatrien-3-one and bicalutamide

The androgen receptor (AR) is a ligand-activated transcription factor that is expressed in primary and metastatic prostate cancers. There are advances in endocrine therapy for prostate cancer that are based on improved understanding of AR function.. PubMed has been used to include most important publications on targeting the AR in prostate cancer. AR expression may be downregulated by agents used for chemoprevention of prostate cancer or, in models of advanced prostate cancer, by antisense oligonucleotides. New drugs that inhibit the steroidogenic enzyme CYP17A1 (abiraterone acetate) or diminish nuclear translocation of the AR (enzalutamide) have been shown to improve patients' survival in prostate cancer. However, it is clear that there is a development of resistance to these novel therapies. They may include increased expression of truncated, constitutively active AR or activation of the signaling pathway of signal transducers and activators of transcription.. Although introduction of novel drugs have improved patients' survival, there is a need to investigate the mechanisms of resistance further. The role of truncated AR and compensatory activation of signaling pathways as well as the development of scientifically justified combination therapies seems to be issues of a high priority.

Topics: Androgen Antagonists; Anilides; Antibodies, Neutralizing; Anticarcinogenic Agents; Antineoplastic Agents; Benzamides; Cell Line, Tumor; Curcumin; Flutamide; Histone Deacetylase Inhibitors; HSP90 Heat-Shock Proteins; Humans; Male; Molecular Targeted Therapy; Nitriles; Oligonucleotides, Antisense; Phenylthiohydantoin; Phosphatidylinositol 3-Kinases; Prostatic Neoplasms; Receptors, Androgen; Signal Transduction; Steroid 17-alpha-Hydroxylase; Tosyl Compounds

Despite the fact that androgen deprivation therapy (ADT) can effectively reduce prostate cancer (PCa) size, its effect on PCa metastasis remains unclear. We examined the existing data on PCa patients treated with ADT plus anti-androgens to analyze ADT effects on primary tumor size, prostate-specific antigen (PSA) values, and metastatic incidence. We found that the current ADT with anti-androgens might lead to primary tumor reduction, with PSA decreased yet metastases increased in some PCa patients. Using in vitro and in vivo metastasis models with four human PCa cell lines, we evaluated the effects of the currently used anti-androgens, Casodex/bicalutamide and MDV3100/enzalutamide, and the newly developed anti-AR compounds, ASC-J9® and cryptotanshinone, on PCa cell growth and invasion. In vitro results showed that 10 μm Casodex or MDV3100 treatments suppressed PCa cell growth and reduced PSA level yet significantly enhanced PCa cell invasion. In vivo mice studies using an orthotopic xenograft mouse model also confirmed these results. In contrast, ASC-J9® led to suppressed PCa cell growth and cell invasion in in vitro and in vivo models. Mechanism dissection indicated these Casodex/MDV3100 treatments enhanced the TGF-β1/Smad3/MMP9 pathway, but ASC-J9® and cryptotanshinone showed promising anti-invasion effects via down-regulation of MMP9 expression. These findings suggest the potential risks of using anti-androgens and provide a potential new therapy using ASC-J9® to battle PCa metastasis at the castration-resistant stage.

Topics: Androgen Receptor Antagonists; Androgens; Anilides; Animals; Benzamides; Cell Line, Tumor; Curcumin; Down-Regulation; Gene Expression Regulation, Enzymologic; Gene Expression Regulation, Neoplastic; Humans; Male; Matrix Metalloproteinase 9; Mice; Mice, Nude; Neoplasm Invasiveness; Neoplasm Metastasis; Neoplasm Proteins; Neoplasm Transplantation; Neoplasms, Experimental; Nitriles; Phenylthiohydantoin; Prostate-Specific Antigen; Prostatic Neoplasms; Smad3 Protein; Tosyl Compounds; Transforming Growth Factor beta1; Transplantation, Heterologous; Xenograft Model Antitumor Assays

Early studies suggested that prostate cancer (PCa) stem/progenitor (S/P) cells might play key roles to promote the tumor initiation and metastasis. Yet their linkage to the failure of androgen deprivation therapy (ADT), however, remains unclear. Here we demonstrated that the ADT with anti-androgens Casodex (also known as Bicalutamide) and Enzalutamide (also known as MDV3100), but not the newly identified AR degradation enhancer, ASC-J9(®), increased PCa S/P population, which might then lead to enhance the PCa cell invasion. Targeting AR with ASC-J9(®), and not targeting androgens with Casodex or Enzalutamide, led to suppress PCa S/P cell invasion. Mechanism dissection revealed ASC-J9(®) could suppress S/P cell invasion via altering the EZH2/STAT3 and/or AKT/EZH2/STAT3 signals. Together, these results suggest that targeting PCa S/P cells with ASC-J9(®) or inhibitors to interrupt the EZH2/STAT3 and/or Akt/EZH2/STAT3 signals may become a new therapy to overcome the unwanted side effects of Casodex or Enzalutamide to further suppress the PCa metastasis.

Topics: Androgen Antagonists; Anilides; Animals; Antineoplastic Agents, Hormonal; Benzamides; Cell Line, Tumor; Cell Movement; Curcumin; Enhancer of Zeste Homolog 2 Protein; Humans; Male; Mice, Nude; Neoplasm Invasiveness; Neoplastic Stem Cells; Nitriles; Phenylthiohydantoin; Prostatic Neoplasms; Proto-Oncogene Proteins c-akt; Side-Population Cells; Signal Transduction; STAT3 Transcription Factor; Tosyl Compounds; Xenograft Model Antitumor Assays

Despite androgen deprivation therapy (ADT) suppression of prostate cancer (PCa) growth, its overall effects on PCa metastasis remain unclear. Using human (C4-2B/THP1) and mouse (TRAMP-C1/RAW264.7) PCa cells-macrophages co-culture systems, we found currently used anti-androgens, MDV3100 (enzalutamide) or Casodex (bicalutamide), promoted macrophage migration to PCa cells that consequently led to enhanced PCa cell invasion. In contrast, the AR degradation enhancer, ASC-J9, suppressed both macrophage migration and subsequent PCa cell invasion. Mechanism dissection showed that Casodex/MDV3100 reduced the AR-mediated PIAS3 expression and enhanced the pSTAT3-CCL2 pathway. Addition of CCR2 antagonist reversed the Casodex/MDV3100-induced macrophage migration and PCa cell invasion. In contrast, ASC-J9 could regulate pSTAT3-CCL2 signaling using two pathways: an AR-dependent pathway via inhibiting PIAS3 expression and an AR-independent pathway via direct inhibition of the STAT3 phosphorylation/activation. These findings were confirmed in the in vivo mouse model with orthotopically injected TRAMP-C1 cells. Together, these results may raise the potential concern about the currently used ADT with anti-androgens that promotes PCa metastasis and may provide some new and better therapeutic strategies using ASC-J9 alone or a combinational therapy that simultaneously targets androgens/AR signaling and PIAS3-pSTAT3-CCL2 signaling to better battle PCa growth and metastasis at castration-resistant stage.

Topics: Androgen Antagonists; Androgen Receptor Antagonists; Anilides; Animals; Antineoplastic Agents; Benzamides; Cell Movement; Chemokine CCL3; Coculture Techniques; Curcumin; Humans; Macrophages; Male; Mice; Neoplasm Metastasis; Nitriles; Phenylthiohydantoin; Prostatic Neoplasms; Signal Transduction; STAT3 Transcription Factor; Tosyl Compounds

Early studies suggested androgen receptor (AR) splice variants might contribute to the progression of prostate cancer (PCa) into castration resistance. However, the therapeutic strategy to target these AR splice variants still remains unresolved. Through tissue survey of tumors from the same patients before and after castration resistance, we found that the expression of AR3, a major AR splice variant that lacks the AR ligand-binding domain, was substantially increased after castration resistance development. The currently used antiandrogen, Casodex, showed little growth suppression in CWR22Rv1 cells. Importantly, we found that AR degradation enhancer ASC-J9 could degrade both full-length (fAR) and AR3 in CWR22Rv1 cells as well as in C4-2 and C81 cells with addition of AR3. The consequences of such degradation of both fAR and AR3 might then result in the inhibition of AR transcriptional activity and cell growth in vitro. More importantly, suppression of AR3 specifically by short-hairpin AR3 or degradation of AR3 by ASC-J9 resulted in suppression of AR transcriptional activity and cell growth in CWR22Rv1-fARKD (fAR knockdown) cells in which DHT failed to induce, suggesting the importance of targeting AR3. Finally, we demonstrated the in vivo therapeutic effects of ASC-J9 by showing the inhibition of PCa growth using the xenografted model of CWR22Rv1 cells orthotopically implanted into castrated nude mice with undetectable serum testosterone. These results suggested that targeting both fAR- and AR3-mediated PCa growth by ASC-J9 may represent the novel therapeutic approach to suppress castration-resistant PCa. Successful clinical trials targeting both fAR and AR3 may help us to battle castration-resistant PCa in the future.

Topics: Androgen Antagonists; Anilides; Animals; Antineoplastic Agents; Blotting, Western; Castration; Cell Line, Tumor; Curcumin; Drug Resistance, Neoplasm; Humans; Immunohistochemistry; Male; Mice; Mice, Nude; Nitriles; Prostatic Neoplasms; Protein Isoforms; Real-Time Polymerase Chain Reaction; Receptors, Androgen; Tosyl Compounds