Effect of generation 2.5 antisense inhibitor of androgen receptor on MDV3100-resistant prostate cancer cell growth in vitro and in vivo.

94 Background: MDV3100 is a potent androgen receptor (AR) antagonist with activity in castration resistant prostate cancer (CRPC); however, progression to MDV3100-resistant (MDV-R) CRPC frequently occurs with rising serum PSA levels, implicating AR full length or variants in disease progression. We studied the activity of Generation 2.5 antisense oligonucleotide (ASO) targeting the AR full length (ARfl) and splice variants in MDV-R CRPC models. Methods: and Results: ThreeASOs targeting exon 1, intron 1, or exon 8 were designed to suppress ARfl and known AR splice variants. We generated by selection MDV-R LNCaP-derived sub-lines that uniformly expressed high levels of both ARfl and AR-V7 compared to CRPC LNCaP cell lines. MDV-3100 induced time- and dose-dependent increases in ARfl and AR-V7 protein levels; ARfl levels were ~20-fold higher than AR-V7. All 3 AR-ASO decreased ARfl and PSA expression. Exon 1 ASO decreased expression of both ARfl and AR-V7 in MDV-R-LNCaP cells; in contrast, exon 8 ASO decreased ARfl without reducing AR-V7 levels. Exon 1 ASO also most potently suppressed ARfl and splice variants in M12 cells stably overexpressing AR splice variants AR-V7 and AR-V567es. Despite these differential effects on ARfl and splice variant knockdown, the AR ASO similarly inhibited cell growth and induced apoptosis and G1 cell cycle arrest in LNCaP-derived CRPC and MDV-R cell lines. In 22RV-1 cells (which express endogenous ARfl and AR-V7), exon 1 ASO more potently suppressed ARfl and AR-V7 levels, AR transcriptional activity and AR-regulated gene expression compared to exon 8 ASO, but inhibition of cell growth did not differ significantly. Exon 1 ASO was evaluated in vivo in MDV-R49F CRPC LNCaP xenografts; mean tumor volume and serum PSA levels decreased significantly by 40% and 50%, respectively, compared to controls. Conclusions: While MDV-3100 induces both ARfl and AR-V7 levels, the biologic consequences appear cell line dependent and mainly driven by ARfl. AR-ASO knockdown of ARfl and its splice variants suppresses MDV-R LNCaP tumor growth, providing pre-clinical proof of principle to support clinical evaluation in post-AR pathway inhibitor CRPC.

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Development of an Androgen Receptor Inhibitor Targeting the N-Terminal Domain of Androgen Receptor for Treatment of Castration Resistant Prostate Cancer

Cancers ◽

10.3390/cancers13143488 ◽

2021 ◽

Vol 13 (14) ◽

pp. 3488

Author(s):

Fuqiang Ban ◽

Eric Leblanc ◽

Ayse Derya Cavga ◽

Chia-Chi Flora Huang ◽

Mark R. Flory ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Splice Variants ◽

Full Length ◽

Cancer Resistance ◽

Castration Resistant Prostate Cancer ◽

Terminal Domain ◽

Castration Resistant ◽

Coregulatory Proteins ◽

Androgen Binding

Prostate cancer patients undergoing androgen deprivation therapy almost invariably develop castration-resistant prostate cancer. Resistance can occur when mutations in the androgen receptor (AR) render anti-androgen drugs ineffective or through the expression of constitutively active splice variants lacking the androgen binding domain entirely (e.g., ARV7). In this study, we are reporting the discovery of a novel AR-NTD covalent inhibitor 1-chloro-3-[(5-([(2S)-3-chloro-2-hydroxypropyl]amino)naphthalen-1-yl)amino]propan-2-ol (VPC-220010) targeting the AR-N-terminal Domain (AR-NTD). VPC-220010 inhibits AR-mediated transcription of full length and truncated variant ARV7, downregulates AR response genes, and selectively reduces the growth of both full-length AR- and truncated AR-dependent prostate cancer cell lines. We show that VPC-220010 disrupts interactions between AR and known coactivators and coregulatory proteins, such as CHD4, FOXA1, ZMIZ1, and several SWI/SNF complex proteins. Taken together, our data suggest that VPC-220010 is a promising small molecule that can be further optimized into effective AR-NTD inhibitor for the treatment of CRPC.

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Biologic consequences of androgen receptor (AR) activity in MDV3100-resistant LNCaP cells and dependence on AR full length.

Journal of Clinical Oncology ◽

10.1200/jco.2014.32.4_suppl.74 ◽

2014 ◽

Vol 32 (4_suppl) ◽

pp. 74-74

Author(s):

Yoshiaki Yamamoto ◽

Yohann Loriot ◽

Eliana Beraldi ◽

Tianyuan Zhou ◽

Youngsoo Kim ◽

...

Keyword(s):

Gene Expression ◽

Androgen Receptor ◽

Cell Growth ◽

Functional Role ◽

Full Length ◽

Lncap Cells ◽

Exon 1

74 Background: While recent reports link androgen receptor (AR) variants (AR-Vs) to castration resistant prostate cancer (CRPC), the biological significance of AR-Vs in AR-regulated cell survival and proliferation, independent of AR full length (AR-FL), remains controversial. To define the functional role of AR-FL and AR-Vs in MDV3100-resistant (MDV-R), we designed antisense oligonucleotide (ASO) targeting exon 1 and exon 8 in AR to knockdown AR-FL alone or in combination with AR-Vs and examined these effects in MDV-R LNCaP-derived cells in vitro and in vivo. Methods: We generated by selection MDV-R LNCaP-derived sub-lines that uniformly expressed high levels of both AR-FL and AR-V7 compared to CRPC LNCaP xenografts. Cell growth rates, protein and gene expression were analyzed using crystal violet assay, western blotting and real-time PCR, respectively. Exon 1 and 8 AR-ASO were evaluated in MDV-R49F CRPC LNCaP xenografts. Results: AR-V7 was transiently transfected in MDV-R49F cells and differential knockdown of AR-V7 and/or AR-FL by exon 1 versus exon 8 AR-ASO was used to evaluate relative biologic contributions of AR-FL versus AR-V7 in MDV-R LNCaP AR-V7 overexpressing cells. Exon 1 and 8 AR-ASO treatment in these cells similarly decreased prostate-specific antigen (PSA) expression and induced apoptosis as measured by caspase-3 and PARP cleavage and cell growth inhibition. To further define the functional role of AR-Vs in MDV-R LNCaP cells, we used a CE3 siRNA that specifically silenced AR-V7, but not AR-FL in MDV-R LNCaP cells. AR-V7 knockdown did not decrease PSA levels, did not induce apoptosis, and did not inhibit cell growth. In MDV-R LNCaP cells, exon 1 and 8 ASO similarly suppressed cell growth and AR-regulated gene expression in vitro and in vivo. Conclusions: These results indicate that the AR remains an important driver of MDV3100 resistance and, the biologic consequences mainly driven by AR-FL in MDV-R LNCaP models.

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Re: Androgen Receptor Splice Variants Mediate Enzalutamide Resistance in Castration-resistant Prostate Cancer Cell Lines

European Urology ◽

10.1016/j.eururo.2013.05.012 ◽

2013 ◽

Vol 64 (2) ◽

pp. 339-340 ◽

Cited By ~ 5

Author(s):

Jun Luo ◽

Kenneth J. Pienta

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cell Lines ◽

Cancer Cell ◽

Prostate Cancer Cell ◽

Splice Variants ◽

Cancer Cell Lines ◽

Castration Resistant Prostate Cancer ◽

Prostate Cancer Cell Lines ◽

Castration Resistant

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Constitutively active androgen receptor splice variants expressed in castration-resistant prostate cancer require full-length androgen receptor

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1012443107 ◽

2010 ◽

Vol 107 (39) ◽

pp. 16759-16765 ◽

Cited By ~ 424

Author(s):

P. A. Watson ◽

Y. F. Chen ◽

M. D. Balbas ◽

J. Wongvipat ◽

N. D. Socci ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Splice Variants ◽

Full Length ◽

Castration Resistant Prostate Cancer ◽

Castration Resistant ◽

Androgen Receptor Splice Variants ◽

Constitutively Active

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Blocking GRP/GRP-R Signaling Decreases Expression of Androgen Receptor Splice Variants and Inhibits Tumor Growth in Castration-resistant Prostate Cancer

10.21203/rs.3.rs-164004/v1 ◽

2021 ◽

Author(s):

Thomas C Case ◽

Alyssa Merkel ◽

Marisol Ramirez-Solano ◽

Qi Liu ◽

Julie A Sterling ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Tumor Growth ◽

Cancer Progression ◽

Fluorescent Protein ◽

Splice Variants ◽

Castration Resistant Prostate Cancer ◽

Castration Resistant ◽

Reporter Vector

Abstract Background: Clinical management of castration-resistant prostate cancer (CRPC) resulting from androgen deprivation therapy (ADT) remains challenging. Previously, we have reported that long-term ADT increases the neuroendocrine (NE) hormone – Gastrin Releasing Peptide (GRP) and its receptor (GRP-R) expression in prostate cancer (PC) cells. Further, we demonstrated that activation of GRP/GRP-R signaling increases androgen receptor (AR) splice variants (ARVs) expression through activating NF-κB signaling thereby contributing cancer progression to CRPC. Most importantly, as a cell surface protein, GRP-R is easily targeted by drugs to block GRP/GRP-R signaling. Here, we aim to investigate if blocking GRP/GRP-R signaling by targeting GRP-R using GRP-R antagonist is sufficient to control CRPC progression, including in therapy-induced (t) neuroendocrine prostate cancer (tNEPC). Methods: Bone-growing NEPC cells were generated by treating androgen dependent LNCaP PC cells with anti-androgen (MDV3100) for more than 3 months. RC-3095, a selective GRP-R antagonist, was used for blocking GRP/GRP-R signaling. The NGL vector [a NF-kB responsive reporter vector which has Luciferase and Green Fluorescent Protein (GFP) reporter genes] was used to measure NF-kB activity and the ARR2PB-Luc vector (an AR responsive reporter vector) was used to measure AR activity in the PC cells. For in vivo experiments, the effect of RC-3095 on CRPC was observed in subcutaneous CRPC and bone-growing tNEPC tumor models.Results: Our studies show that blocking GRP/GRP-R signal by targeting GRP-R using RC-3095 efficiently inhibits NF-κB activity and ARVs (AR-V7) expression in CRPC and tNEPC cells. In addition, blocking of GRP/GRP-R signaling by targeting GRP-R can sensitize CRPC cells to anti-androgen treatment. Further, preclinical animal studies indicate combination of GRP-R antagonist (targeting ARVs) with anti-androgen [targeting full-length AR (AR-FL)] is sufficient to inhibit CRPC and tNEPC tumor growth.Conclusion: Our findings strongly indicate that blocking of GRP/GRP-R signaling in combination with ADT is a potential new approach to control CRPC tumor growth, including ADT induced tNEPC.

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Androgen Receptor Splice Variants Mediate Enzalutamide Resistance in Castration-Resistant Prostate Cancer Cell Lines

Cancer Research ◽

10.1158/0008-5472.can-12-3630 ◽

2012 ◽

Vol 73 (2) ◽

pp. 483-489 ◽

Cited By ~ 377

Author(s):

Yingming Li ◽

Siu Chiu Chan ◽

Lucas J. Brand ◽

Tae Hyun Hwang ◽

Kevin A.T. Silverstein ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cell Lines ◽

Cancer Cell ◽

Prostate Cancer Cell ◽

Splice Variants ◽

Cancer Cell Lines ◽

Castration Resistant Prostate Cancer ◽

Prostate Cancer Cell Lines ◽

Castration Resistant

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321 ANTISENSE INHIBITOR TARGETING FULL LENGTH ANDROGEN RECEPTOR AND ITS SPLICE VARIANTS SUPPRESSES MDV3100 RESISTANT PROSTATE CANCER CELL GROWTH

The Journal of Urology ◽

10.1016/j.juro.2013.02.1706 ◽

2013 ◽

Vol 189 (4S) ◽

Author(s):

Yoshiaki Yamamoto ◽

Eliana Beraldi ◽

Hidetoshi Kuruma ◽

Hiroaki Matsumoto ◽

Yohann Loriot ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cell Growth ◽

Cancer Cell ◽

Prostate Cancer Cell ◽

Splice Variants ◽

Full Length ◽

Cancer Cell Growth

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An oral androgen receptor PROTAC degrader for prostate cancer.

Journal of Clinical Oncology ◽

10.1200/jco.2017.35.6_suppl.273 ◽

2017 ◽

Vol 35 (6_suppl) ◽

pp. 273-273 ◽

Cited By ~ 6

Author(s):

Taavi K Neklesa ◽

Lawrence B Snyder ◽

Mark Bookbinder ◽

Xin Chen ◽

Andrew P Crew ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cell Lines ◽

Genetic Alterations ◽

Tumor Growth Inhibition ◽

Castration Resistant Prostate Cancer ◽

Null Cell ◽

Orally Bioavailable

273 Background: The Androgen Receptor (AR) remains the principal driver of castration-resistant prostate cancer during the transition from a localized to metastatic disease. Most patients initially respond to inhibitors of the AR pathway, but the response is often short-lived. The majority of patients progressing on enzalutamide or abiraterone exhibit genetic alterations in the AR locus, either in the form of amplifications or point mutations in the AR gene. Given these mechanisms of resistance, our goal is to eliminate the AR protein using the PROteolysis TArgeting Chimera (PROTAC) technology. Further, we sought to make an orally bioavailable AR PROTAC. Methods: Medicinal chemistry efforts yielded a small molecule AR PROTAC that simultaneously binds E3-ubiquitin ligase and AR, thus leading to ubiquitination and degradation of AR. This molecule has been characterized in in vitro and in vivo preclinical studies. Results: Our lead oral AR PROTAC degrades 92-98% of total AR in all cell lines tested, with 50% degradation concentration (DC50) < 1 nM. AR degradation suppresses the expression of AR-target gene PSA, inhibits cell proliferation, and induces potent apoptosis in VCaP cells. No activity is observed in AR-null cell lines, such as PC-3. While enzalutamide loses its activity in the presence of elevated androgens, AR PROTAC maintains its antiproliferative activity. Further, AR PROTAC is able to degrade all clinically relevant mutant AR proteins. A robust oral bioavailability is observed across multiple species and overall ADME properties are encouraging. Approximately 95% AR degradation is observed in AR-amplified VCaP xenografts at doses as low as 10 mg/kg. Congruent with AR degradation, a dose responsive tumor growth inhibition is observed in AR-dependent xenograft studies. Conclusions: In summary, we report the first orally bioavailable AR PROTAC that robustly degrades AR in vitro and in vivo.

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