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Similarities and Distinctions in Actions of Surface-Directed and Classic Androgen Receptor Antagonists.

Suh JH, Chattopadhyay A, Sieglaff DH, Storer Samaniego C, Cox MB, Webb P - PLoS ONE (2015)

Bottom Line: Here, we compared MJC13 and classic AR antagonists such as flutamide and bicalutamide.Both compounds are equally effective on a genome wide basis and as effective as second generation AR antagonists (MDV3100, ARN-509) at selected genes.Thus, a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in particular forms of CRPC.

View Article: PubMed Central - PubMed

Affiliation: Genomic Medicine Program, Houston Methodist Research Institute, 66670 Bertner Avenue, R8-114, Houston, Texas, 77030, United States of America.

ABSTRACT
The androgen receptor (AR) surface-directed antagonist MJC13 inhibits AR function and proliferation of prostate cancer (PC) cells. These effects are related to arrest of an AR/chaperone complex in the cytoplasm. Here, we compared MJC13 and classic AR antagonists such as flutamide and bicalutamide. Microarray analysis and confirmatory qRT-PCR reveals that MJC13 and flutamide inhibit dihydrotestosterone (DHT)-dependent genes in LNCaP PC cells. Both compounds are equally effective on a genome wide basis and as effective as second generation AR antagonists (MDV3100, ARN-509) at selected genes. MJC13 inhibits AR binding to the prostate specific antigen (PSA) promoter more strongly than flutamide, consistent with different mechanisms of action. Examination of efficacy of MJC13 in conditions that reflect aspects castrate resistant prostate cancer (CRPC) reveals that it inhibits flutamide activation of an AR mutant (ART877A) that emerges during flutamide withdrawal syndrome, but displays greatly restricted gene-specific activity in 22Rv1 cells that express a constitutively active truncated AR and is inactive against glucocorticoid receptor (GR), which can co-opt androgen-dependent signaling networks in CRPC. Importantly, MJC13 inhibits AR interactions with SRC2 and β-catenin in the nucleus and, unlike flutamide, strongly inhibits amplification of AR activity obtained with transfected SRC2 and β-catenin. MJC13 also inhibits DHT and β-catenin-enhanced cell division in LNCaP cells. Thus, a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in particular forms of CRPC.

No MeSH data available.


Related in: MedlinePlus

Effects of AR antagonists are blunted in 22RV1 cells.(A) Luciferase activity measured in 22RV1 cells transfected with ARE-luc reporter and treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) overnight, with quantities of plasmids as in Fig 1A. All data are representative of at least three independent experiments with similar results. All values represent the mean ± SD of duplicate samples. (B-C) qPCR analysis of 22RV1 cells extracts treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) for 24 hours. The data are representative of at least three independent experiments. All values represent the mean ± SD of triplicate samples. Genes are TMPRSS2 (B) and PSA (C).
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pone.0137103.g006: Effects of AR antagonists are blunted in 22RV1 cells.(A) Luciferase activity measured in 22RV1 cells transfected with ARE-luc reporter and treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) overnight, with quantities of plasmids as in Fig 1A. All data are representative of at least three independent experiments with similar results. All values represent the mean ± SD of duplicate samples. (B-C) qPCR analysis of 22RV1 cells extracts treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) for 24 hours. The data are representative of at least three independent experiments. All values represent the mean ± SD of triplicate samples. Genes are TMPRSS2 (B) and PSA (C).

Mentions: We next compared activities of both compounds in 22RV1 cells, which express wild type AR and a truncated AR variant with constitutive activity [36]. We observed modest DHT activation of an ARE responsive reporter in this cell line and this effect was suppressed by flutamide and MJC13 (Fig 6A). We also observed MJC13-specific suppression of DHT response at the TMPRSS2 gene (Fig 6B). However, MJC13 failed to exhibit strong suppressive effects at other DHT-induced genes, including PSA (Fig 6C) and others (S4 Fig) in this cell background. Further, we observed that several genes which respond to DHT in LNCaP (ORM2, WDR76, KLK2 and TRPM8) did not exhibit DHT response in 22RV1 and, here, MJC13 had no effect (not shown). This suggests that the presence of the truncated variant AR alters the spectrum of androgen responsive and curtails a large proportion of MJC13 suppressive effects.


Similarities and Distinctions in Actions of Surface-Directed and Classic Androgen Receptor Antagonists.

Suh JH, Chattopadhyay A, Sieglaff DH, Storer Samaniego C, Cox MB, Webb P - PLoS ONE (2015)

Effects of AR antagonists are blunted in 22RV1 cells.(A) Luciferase activity measured in 22RV1 cells transfected with ARE-luc reporter and treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) overnight, with quantities of plasmids as in Fig 1A. All data are representative of at least three independent experiments with similar results. All values represent the mean ± SD of duplicate samples. (B-C) qPCR analysis of 22RV1 cells extracts treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) for 24 hours. The data are representative of at least three independent experiments. All values represent the mean ± SD of triplicate samples. Genes are TMPRSS2 (B) and PSA (C).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4557941&req=5

pone.0137103.g006: Effects of AR antagonists are blunted in 22RV1 cells.(A) Luciferase activity measured in 22RV1 cells transfected with ARE-luc reporter and treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) overnight, with quantities of plasmids as in Fig 1A. All data are representative of at least three independent experiments with similar results. All values represent the mean ± SD of duplicate samples. (B-C) qPCR analysis of 22RV1 cells extracts treated +/- DHT (1nM), +/- Flutamide (1μM), or +/- MJC13 (30μM) for 24 hours. The data are representative of at least three independent experiments. All values represent the mean ± SD of triplicate samples. Genes are TMPRSS2 (B) and PSA (C).
Mentions: We next compared activities of both compounds in 22RV1 cells, which express wild type AR and a truncated AR variant with constitutive activity [36]. We observed modest DHT activation of an ARE responsive reporter in this cell line and this effect was suppressed by flutamide and MJC13 (Fig 6A). We also observed MJC13-specific suppression of DHT response at the TMPRSS2 gene (Fig 6B). However, MJC13 failed to exhibit strong suppressive effects at other DHT-induced genes, including PSA (Fig 6C) and others (S4 Fig) in this cell background. Further, we observed that several genes which respond to DHT in LNCaP (ORM2, WDR76, KLK2 and TRPM8) did not exhibit DHT response in 22RV1 and, here, MJC13 had no effect (not shown). This suggests that the presence of the truncated variant AR alters the spectrum of androgen responsive and curtails a large proportion of MJC13 suppressive effects.

Bottom Line: Here, we compared MJC13 and classic AR antagonists such as flutamide and bicalutamide.Both compounds are equally effective on a genome wide basis and as effective as second generation AR antagonists (MDV3100, ARN-509) at selected genes.Thus, a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in particular forms of CRPC.

View Article: PubMed Central - PubMed

Affiliation: Genomic Medicine Program, Houston Methodist Research Institute, 66670 Bertner Avenue, R8-114, Houston, Texas, 77030, United States of America.

ABSTRACT
The androgen receptor (AR) surface-directed antagonist MJC13 inhibits AR function and proliferation of prostate cancer (PC) cells. These effects are related to arrest of an AR/chaperone complex in the cytoplasm. Here, we compared MJC13 and classic AR antagonists such as flutamide and bicalutamide. Microarray analysis and confirmatory qRT-PCR reveals that MJC13 and flutamide inhibit dihydrotestosterone (DHT)-dependent genes in LNCaP PC cells. Both compounds are equally effective on a genome wide basis and as effective as second generation AR antagonists (MDV3100, ARN-509) at selected genes. MJC13 inhibits AR binding to the prostate specific antigen (PSA) promoter more strongly than flutamide, consistent with different mechanisms of action. Examination of efficacy of MJC13 in conditions that reflect aspects castrate resistant prostate cancer (CRPC) reveals that it inhibits flutamide activation of an AR mutant (ART877A) that emerges during flutamide withdrawal syndrome, but displays greatly restricted gene-specific activity in 22Rv1 cells that express a constitutively active truncated AR and is inactive against glucocorticoid receptor (GR), which can co-opt androgen-dependent signaling networks in CRPC. Importantly, MJC13 inhibits AR interactions with SRC2 and β-catenin in the nucleus and, unlike flutamide, strongly inhibits amplification of AR activity obtained with transfected SRC2 and β-catenin. MJC13 also inhibits DHT and β-catenin-enhanced cell division in LNCaP cells. Thus, a surface-directed antagonist can block AR activity in some conditions in which a classic antagonist fails and may display utility in particular forms of CRPC.

No MeSH data available.


Related in: MedlinePlus