RESUMO
The NR superfamily comprises 48 transcription factors in humans that control a plethora of gene network programs involved in a wide range of physiologic processes. This review will summarize and discuss recent progress in NR biology and drug development derived from integrating various approaches, including biophysical techniques, structural studies, and translational investigation. We also highlight how defective NR signaling results in various diseases and disorders and how NRs can be targeted for therapeutic intervention via modulation via binding to synthetic lipophilic ligands. Furthermore, we also review recent studies that improved our understanding of NR structure and signaling. SIGNIFICANCE STATEMENT: Nuclear receptors (NRs) are ligand-regulated transcription factors that are critical regulators of myriad physiological processes. NRs serve as receptors for an array of drugs, and in this review, we provide an update on recent research into the roles of these drug targets.
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Farmacologia Clínica , Humanos , Receptores Citoplasmáticos e Nucleares/metabolismo , Fatores de Transcrição/metabolismo , Proteínas de Transporte , LigantesRESUMO
Immune targeted therapy of nitric oxide (NO) synthases are being considered as a potential frontline therapeutic to treat patients diagnosed with locally advanced and metastatic prostate cancer. However, the role of NO in castration-resistant prostate cancer (CRPC) is controversial because NO can increase in nitrosative stress while simultaneously possessing antiinflammatory properties. Accordingly, we tested the hypothesis that increased NO will lead to tumor suppression of CRPC through tumor microenvironment. S-nitrosoglutathione (GSNO), an NO donor, decreased the tumor burden in murine model of CRPC by targeting tumors in a cell nonautonomous manner. GSNO inhibited both the abundance of antiinflammatory (M2) macrophages and expression of pERK, indicating that tumor-associated macrophages activity is influenced by NO. Additionally, GSNO decreased IL-34, indicating suppression of tumor-associated macrophage differentiation. Cytokine profiling of CRPC tumor grafts exposed to GSNO revealed a significant decrease in expression of G-CSF and M-CSF compared with grafts not exposed to GSNO. We verified the durability of NO on CRPC tumor suppression by using secondary xenograft murine models. This study validates the significance of NO on inhibition of CRPC tumors through tumor microenvironment (TME). These findings may facilitate the development of previously unidentified NO-based therapy for CRPC.
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Proliferação de Células/fisiologia , Óxido Nítrico/metabolismo , Neoplasias de Próstata Resistentes à Castração/metabolismo , Neoplasias de Próstata Resistentes à Castração/patologia , Microambiente Tumoral/fisiologia , Animais , Diferenciação Celular/fisiologia , Linhagem Celular Tumoral , Regulação Neoplásica da Expressão Gênica/fisiologia , Inflamação/metabolismo , Inflamação/patologia , Sistema de Sinalização das MAP Quinases/fisiologia , Macrófagos/metabolismo , Macrófagos/patologia , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Doadores de Óxido Nítrico/metabolismo , Carga Tumoral/fisiologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodosRESUMO
Identifying critical pathways governing disease progression is essential for accurate prognosis and effective therapy. We developed a broadly applicable and novel systems-level gene discovery strategy. This approach focused on constitutively active androgen receptor (AR) splice variant-driven pathways as representative of an intractable mechanism of prostate cancer (PC) therapeutic resistance. We performed a meta-analysis of human prostate samples using weighted gene co-expression network analysis combined with experimental AR variant transcriptome analyses. An AR variant-driven gene module that is upregulated during human PC progression was identified. We filtered this module by identifying genes that functionally interacted with AR variants using a high-throughput synthetic genetic array screen in Schizosaccharomyces pombe This strategy identified seven AR variant-regulated genes that also enhance AR activity and drive cancer progression. Expression of the seven genes predicted poor disease-free survival in large independent PC patient cohorts. Pharmacologic inhibition of interacting members of the gene set potently and synergistically decreased PC cell proliferation. This unbiased and novel gene discovery strategy identified a clinically relevant, oncogenic, interacting gene hub with strong prognostic and therapeutic potential in PC.
Assuntos
Carcinogênese/genética , Proliferação de Células/genética , Neoplasias da Próstata/genética , Receptores Androgênicos/genética , Linhagem Celular Tumoral , Intervalo Livre de Doença , Resistencia a Medicamentos Antineoplásicos/genética , Perfilação da Expressão Gênica/métodos , Regulação Neoplásica da Expressão Gênica , Humanos , Masculino , Prognóstico , Neoplasias da Próstata/patologia , Splicing de RNA/genética , Receptores Androgênicos/química , Schizosaccharomyces/genética , Transdução de Sinais/genéticaRESUMO
Advanced hormone-sensitive prostate cancer responds to androgen-deprivation therapy (ADT); however, therapeutic options for recurrent castration-resistant disease are limited. Because growth hormone-releasing hormone (GHRH) and GHRH receptor (GHRH-R) are regulated in an autocrine fashion in prostate cancer, inhibition of GHRH-R represents a compelling approach to treatment. We investigated the effects of the latest series of improved, highly potent GHRH antagonists--MIA-602, MIA-606, and MIA-690--on the growth of androgen-dependent as well as castration-resistant prostate cancer (CRPC) cells in vitro and in vivo. GHRH-R and its splice variant, SV1, were present in 22Rv1, LNCaP, and VCaP human prostate cancer cell lines. Androgen-dependent LNCaP and VCaP cells expressed higher levels of GHRH-R protein compared with castration-resistant 22Rv1 cells; however, 22Rv1 expressed higher levels of SV1. In vitro, MIA-602 decreased cell proliferation of 22Rv1, LNCaP, and VCaP prostate cancer cell lines by 70%, 61%, and 20%, respectively (all P < 0.05), indicating direct effects of MIA-602. In vivo, MIA-602 was more effective than MIA-606 and MIA-690 and decreased 22Rv1 xenograft tumor volumes in mice by 63% after 3 wk (P < 0.05). No noticeable untoward effects or changes in body weight occurred. In vitro, the VCaP cell line was minimally inhibited by MIA-602, but in vivo, this line showed a substantial reduction in growth of xenografts in response to MIA-602, indicating both direct and systemic inhibitory effects. MIA-602 also further inhibited VCaP xenografts when combined with ADT. This study demonstrates the preclinical efficacy of the GHRH antagonist MIA-602 for treatment of both androgen-dependent and CRPC.
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Androgênios/metabolismo , Hormônio Liberador de Hormônio do Crescimento/antagonistas & inibidores , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias da Próstata/tratamento farmacológico , Animais , Peso Corporal , Linhagem Celular Tumoral , Proliferação de Células , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Hipotálamo/metabolismo , Ligantes , Masculino , Camundongos , Camundongos Nus , Transplante de Neoplasias , Antígeno Prostático Específico/metabolismo , Receptores Acoplados a Proteínas G/metabolismo , Fatores de TempoRESUMO
Elevated androgen receptor (AR) activity in castration-resistant prostate cancer may occur through increased levels of AR co-activator proteins. Vav3, a guanine nucleotide exchange factor, is up-regulated following progression to castration resistance in preclinical models and is overexpressed in a significant number of human prostate cancers. Vav3 is a novel co-activator of the AR. We sought to identify Vav3 binding partners in an effort to understand the molecular mechanisms underlying Vav3 enhancement of AR activity and to identify new therapeutic targets. The cell division cycle 37 homolog (Cdc37), a protein kinase-specific co-chaperone for Hsp90, was identified as a Vav3 interacting protein by yeast two-hybrid screening. Vav3-Cdc37 interaction was confirmed by GST pulldown and, for native proteins, by co-immunoprecipitation experiments in prostate cancer cells. Cdc37 potentiated Vav3 co-activation of AR transcriptional activity and Vav3 enhancement of AR N-terminal-C-terminal interaction, which is essential for optimal receptor transcriptional activity. Cdc37 increased prostate cancer cell proliferation selectively in Vav3-expressing cells. Cdc37 did not affect Vav3 nucleotide exchange activity, Vav3 protein levels, or subcellular localization. Disruption of Vav3-Cdc37 interaction inhibited Vav3 enhancement of AR transcriptional activity and AR N-C interaction. Diminished Vav3-Cdc37 interaction also caused decreased prostate cancer cell proliferation selectively in Vav3-expressing cells. Taken together, we identified a novel Vav3 interacting protein that enhances Vav3 co-activation of AR and prostate cancer cell proliferation. Vav3-Cdc37 interaction may provide a new therapeutic target in prostate cancer.
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Proteínas de Ciclo Celular/metabolismo , Chaperoninas/metabolismo , Regulação Neoplásica da Expressão Gênica , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-vav/fisiologia , Animais , Células COS , Linhagem Celular Tumoral , Proliferação de Células , Chlorocebus aethiops , Glutationa Transferase/metabolismo , Fatores de Troca do Nucleotídeo Guanina/metabolismo , Células HEK293 , Humanos , Masculino , Chaperonas Moleculares/metabolismo , Ligação Proteica , Proteínas Proto-Oncogênicas c-vav/metabolismo , Técnicas do Sistema de Duplo-HíbridoRESUMO
INTRODUCTION: Endocrine therapies targeting cell proliferation and survival mediated by estrogen receptor α (ERα) are among the most effective systemic treatments for ERα-positive breast cancer. However, most tumors initially responsive to these therapies acquire resistance through mechanisms that involve ERα transcriptional regulatory plasticity. Herein we identify VAV3 as a critical component in this process. METHODS: A cell-based chemical compound screen was carried out to identify therapeutic strategies against resistance to endocrine therapy. Binding to ERα was evaluated by molecular docking analyses, an agonist fluoligand assay and short hairpin (sh)RNA-mediated protein depletion. Microarray analyses were performed to identify altered gene expression. Western blot analysis of signaling and proliferation markers, and shRNA-mediated protein depletion in viability and clonogenic assays, were performed to delineate the role of VAV3. Genetic variation in VAV3 was assessed for association with the response to tamoxifen. Immunohistochemical analyses of VAV3 were carried out to determine its association with therapeutic response and different tumor markers. An analysis of gene expression association with drug sensitivity was carried out to identify a potential therapeutic approach based on differential VAV3 expression. RESULTS: The compound YC-1 was found to comparatively reduce the viability of cell models of acquired resistance. This effect was probably not due to activation of its canonical target (soluble guanylyl cyclase), but instead was likely a result of binding to ERα. VAV3 was selectively reduced upon exposure to YC-1 or ERα depletion, and, accordingly, VAV3 depletion comparatively reduced the viability of cell models of acquired resistance. In the clinical scenario, germline variation in VAV3 was associated with the response to tamoxifen in Japanese breast cancer patients (rs10494071 combined P value = 8.4 × 10-4). The allele association combined with gene expression analyses indicated that low VAV3 expression predicts better clinical outcome. Conversely, high nuclear VAV3 expression in tumor cells was associated with poorer endocrine therapy response. Based on VAV3 expression levels and the response to erlotinib in cancer cell lines, targeting EGFR signaling may be a promising therapeutic strategy. CONCLUSIONS: This study proposes VAV3 as a biomarker and a rationale for its use as a signaling target to prevent and/or overcome resistance to endocrine therapy in breast cancer.
Assuntos
Neoplasias da Mama/tratamento farmacológico , Resistencia a Medicamentos Antineoplásicos/genética , Receptor alfa de Estrogênio/metabolismo , Indazóis/farmacologia , Proteínas Proto-Oncogênicas c-vav/genética , Androstadienos/uso terapêutico , Antineoplásicos Hormonais/farmacologia , Inibidores da Aromatase/uso terapêutico , Biomarcadores Tumorais/genética , Mama/patologia , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Ativadores de Enzimas/farmacologia , Receptores ErbB/antagonistas & inibidores , Cloridrato de Erlotinib , Receptor alfa de Estrogênio/antagonistas & inibidores , Receptor alfa de Estrogênio/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Estudos de Associação Genética , Variação Genética , Humanos , Letrozol , Células MCF-7 , Nitrilas/uso terapêutico , Inibidores de Proteínas Quinases/farmacologia , Quinazolinas/farmacologia , Interferência de RNA , RNA Interferente Pequeno , Tamoxifeno/farmacologia , Tamoxifeno/uso terapêutico , Toremifeno/farmacologia , Toremifeno/uso terapêutico , Triazóis/uso terapêuticoRESUMO
PURPOSE: In vivo optical imaging systems are essential to track disease progression and evaluate therapeutic efficacy in animal studies. However, current approaches are limited by their inability to accurately capture 3-dimensional (3-D) image information. To overcome this hindrance, we adopted x-ray computed tomography (CT) as a prior for 3-D optical image reconstruction and further challenged the multimodal imaging performance with a metastasis model. METHODS AND MATERIALS: The iSMAART system, an integrated small animal research platform, features coregistered high-quality quantitative optical tomography and CT. In the synergistic dual-modality imaging, CT provides both 3-D anatomy information and animal structure mesh for optical tomography reconstruction, which is performed using bioluminescence projections acquired from 4 orthogonal angles. The multimodal imaging system was challenged with a prostate cancer metastasis model, and a double-blind histopathology diagnosis was obtained to validate the imaging results. RESULTS: The iSMAART located, visualized, and quantified early tumor metastases at the millimeter scale, and can accurately track deep tumors as small as 1.5 mm in live animals. Tumors metastasized into the liver, diaphragm, and tibia in 4 mice were all successfully diagnosed by the integrated tomographic imaging. CONCLUSIONS: Instead of roughly comparing surface-light intensities, as traditionally performed in 2-dimensional optical imaging, iSMAART provides accurate tumor imaging and quantitative assessment capabilities with integrated CT and optical tomography for cancer metastasis research. With the powerful 3-D optical/CT imaging capability, iSMAART has the potential to tackle more complex research needs with higher targeting accuracy.
Assuntos
Neoplasias da Próstata , Tomografia Óptica , Animais , Masculino , Camundongos , Próstata , Neoplasias da Próstata/diagnóstico por imagem , Tomografia Óptica/métodos , Tomografia Computadorizada por Raios X , Raios XRESUMO
Androgen deprivation therapy (ADT) is the standard of care for high risk and advanced prostate cancer; however, disease progression from androgen-dependent prostate cancer (ADPC) to lethal and incurable castration-resistant prostate cancer (CRPC) and (in a substantial minority of cases) neuroendocrine prostate cancer (NEPC) is common. Identifying effective targeted therapies is challenging because of acquired resistance to established treatments and the vast heterogeneity of advanced prostate cancer (PC). To streamline the identification of potentially active prostate cancer therapeutics, we have developed an adaptable semi-automated protocol which optimizes cell growth and leverages automation to enhance robustness, reproducibility, and throughput while integrating live-cell imaging and endpoint viability assays to assess drug efficacy in vitro. In this study, culture conditions for 72-hr drug screens in 96-well plates were established for a large, representative panel of human prostate cell lines including: BPH-1 and RWPE-1 (non-tumorigenic), LNCaP and VCaP (ADPC), C4-2B and 22Rv1 (CRPC), DU 145 and PC3 (androgen receptor-null CRPC), and NCI-H660 (NEPC). The cell growth and 72-hr confluence for each cell line was optimized for real-time imaging and endpoint viability assays prior to screening for novel or repurposed drugs as proof of protocol validity. We demonstrated effectiveness and reliability of this pipeline through validation of the established finding that the first-in-class BET and CBP/p300 dual inhibitor EP-31670 is an effective compound in reducing ADPC and CRPC cell growth. In addition, we found that insulin-like growth factor-1 receptor (IGF-1R) inhibitor linsitinib is a potential pharmacological agent against highly lethal and drug-resistant NEPC NCI-H660 cells. This protocol can be employed across other cancer types and represents an adaptable strategy to optimize assay-specific cell growth conditions and simultaneously assess drug efficacy across multiple cell lines.
Assuntos
Neoplasias de Próstata Resistentes à Castração , Masculino , Humanos , Neoplasias de Próstata Resistentes à Castração/metabolismo , Androgênios/metabolismo , Reprodutibilidade dos Testes , Antagonistas de Androgênios/uso terapêutico , Sobrevivência Celular , Linhagem Celular Tumoral , Receptores Androgênicos/metabolismo , AutomaçãoRESUMO
Men with incurable castration resistant prostate cancer (CRPC) are typically treated with taxanes; however, drug resistance rapidly develops. We previously identified a clinically relevant seven gene network in aggressive CRPC, which includes the spindle assembly checkpoint (SAC) kinase BUB1. Since SAC is deregulated in taxane resistant PC, we evaluated BUB1 and found that it was over-expressed in advanced PC patient datasets and taxane resistant PC cells. Treatment with a specific BUB1 kinase inhibitor re-sensitized resistant CRPC cells, including cells expressing constitutively active androgen receptor (AR) variants, to clinically used taxanes. Consistent with a role of AR variants in taxane resistance, ectopically expressed AR-V7 increased BUB1 levels and reduced sensitivity to taxanes. This work shows that disruption of BUB1 kinase activity reverted resistance to taxanes, which is essential to advancing BUB1 as a potential therapeutic target for intractable chemotherapy resistant CRPC including AR variant driven CRPC, which lacks durable treatment options.
RESUMO
Androgen deprivation therapy (ADT) is the longstanding treatment for advanced prostate cancer (PC) because androgen receptor (AR) is the key therapeutic vulnerability for this disease. Bipolar androgen therapy (BAT) - the rapid cycling of supraphysiologic androgen (SPA) and low serum testosterone levels - is an alternative concept, but not all patients respond and acquired resistance can occur. In this issue of the JCI, Sena et al. developed a gene signature indicative of high AR activity to predict patient response to BAT, including a decline in both serum prostate-specific antigen (PSA) and tumor volume. Preclinical models showed that AR-mediated suppression of MYC, known to drive PC, was associated with decreased cell growth following SPA treatment. Because BAT eventually leads to resistance, the authors tested cycling between SPA and AR antagonism in a patient-derived xenograft and observed a delay in tumor growth. These findings represent a major step toward the informed use of BAT for advanced PC.
Assuntos
Neoplasias da Próstata , Masculino , Humanos , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/genética , Androgênios , Receptores Androgênicos/genética , Antagonistas de Androgênios/farmacologia , Antagonistas de Androgênios/uso terapêutico , BiomarcadoresRESUMO
Prostate cancer that recurs following androgen-deprivation therapy is termed castration-resistant, which is incurable and is marked by reactivation of androgen receptor (AR) signaling. KIF20A, a kinesin with unique structural features, is overexpressed in human castration-resistant prostate cancer (CRPC) compared to androgen-dependent PC and benign tissue. KIF20A has well-described roles in mitotic processes, but it has a less characterized function in vesicle fission and trafficking within Golgi-driven secretory pathways. Stable expression of KIF20A in androgen-dependent PC cells promoted progression to CRPC through the activation of AR signaling in vitro and in vivo. KIF20A expression resulted in the secretion of autocrine factors in the conditioned media that activated AR and caused castration-resistant proliferation of naïve androgen-dependent cells. Pharmacologic disruption of vesicle biogenesis blocked KIF20A-driven castration-resistant proliferation of androgen-dependent PC. KIF20A depletion or treatment with the KIF20A-specific inhibitor, paprotrain, reduced CRPC. These data are the first to establish KIF20A as a driver of CRPC progression through AR activation and as a promising therapeutic target against CRPC.
Assuntos
Cinesinas , Neoplasias de Próstata Resistentes à Castração , Receptores Androgênicos , Antagonistas de Androgênios/farmacologia , Androgênios/metabolismo , Linhagem Celular Tumoral , Humanos , Cinesinas/genética , Masculino , Recidiva Local de Neoplasia , Neoplasias de Próstata Resistentes à Castração/metabolismo , Receptores Androgênicos/genética , Receptores Androgênicos/metabolismoRESUMO
Men with advanced prostate cancer are treated by androgen deprivation therapy but the disease recurs as incurable castration-resistant prostate cancer (CRPC), requiring new treatment options. We previously demonstrated that the G protein-coupled receptor (GPCR) arginine vasopressin receptor type1A (AVPR1A) is expressed in CRPC and promotes castration-resistant growth in vitro and in vivo. AVPR1A is part of a family of GPCR's including arginine vasopressin receptor type 2 (AVPR2). Interrogation of prostate cancer patient sample data revealed that coexpression of AVPR1A and AVPR2 is highly correlated with disease progression. Stimulation of AVPR2 with a selective agonist desmopressin promoted CRPC cell proliferation through cAMP/protein kinase A signaling, consistent with AVPR2 coupling to the G protein subunit alpha s. In contrast, blocking AVPR2 with a selective FDA-approved antagonist, tolvaptan, reduced cell growth. In CRPC xenografts, antagonizing AVPR2, AVPR1A, or both significantly reduced CRPC tumor growth as well as decreased on-target markers of tumor burden. Combinatorial use of AVPR1A and AVPR2 antagonists promoted apoptosis synergistically in CRPC cells. Furthermore, we found that castration-resistant cells produced AVP, the endogenous ligand for arginine vasopressin receptors, and knockout of AVP in CRPC cells significantly reduced proliferation suggesting possible AVP autocrine signaling. These data indicate that the AVP/arginine vasopressin receptor signaling axis represents a promising and clinically actionable target for CRPC. IMPLICATIONS: The arginine vasopressin signaling axis in CRPC provides a therapeutic window that is targetable through repurposing safe and effective AVPR1A and AVPR2 antagonists.
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Neoplasias de Próstata Resistentes à Castração , Receptores de Vasopressinas , Antagonistas de Androgênios , Arginina Vasopressina/uso terapêutico , Linhagem Celular Tumoral , Humanos , Masculino , Recidiva Local de Neoplasia , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/metabolismo , Receptores Androgênicos/metabolismo , Receptores de Vasopressinas/genética , Receptores de Vasopressinas/metabolismoRESUMO
Environmental sodium arsenite is a toxin that is associated with male infertility due to decreased and abnormal sperm production. Arsenic trioxide (ATO), another inorganic trivalent semimetal, is an effective therapy for acute promyelocytic leukemia, and there is investigation of its possible efficacy in prostate cancer. However, the mechanism of arsenic action in male urogenital tract tissues is not clear. Because the androgen receptor (AR) plays an important role in spermatogenesis and prostate cancer, we explored the possibility that trivalent arsenic regulates AR function. We found that arsenic inhibited AR transcriptional activity in prostate cancer and Sertoli cells using reporter gene assays testing several androgen response element-containing regions and by assessing native target gene expression. Arsenic inhibition of AR activity was not due to down-regulation of AR protein levels, decreased hormone binding to AR, disruption of AR nuclear translocation, or interference with AR-DNA binding in vitro. However, chromatin immunoprecipitation studies revealed that arsenic inhibited AR recruitment to an AR target gene enhancer in vivo. Consistent with a deficiency in AR-chromatin binding, arsenic disrupted AR amino and carboxyl termini interaction. Furthermore, ATO caused a significant decrease in prostate cancer cell proliferation that was more pronounced in cells expressing AR compared with cells depleted of AR. In addition, inhibition of AR activity by ATO and by the AR antagonist, bicalutamide, was additive. Thus, arsenic-induced male infertility may be due to inhibition of AR activity. Further, because AR is an important target in prostate cancer therapy, arsenic may serve as an effective therapeutic option.
Assuntos
Antagonistas de Receptores de Andrógenos , Arsenicais/farmacologia , Óxidos/farmacologia , Ativação Transcricional/efeitos dos fármacos , Antagonistas de Androgênios/farmacologia , Androgênios/metabolismo , Androgênios/farmacologia , Anilidas/administração & dosagem , Anilidas/farmacologia , Protocolos de Quimioterapia Combinada Antineoplásica/farmacologia , Trióxido de Arsênio , Arsenicais/administração & dosagem , Núcleo Celular/efeitos dos fármacos , Núcleo Celular/metabolismo , Proliferação de Células/efeitos dos fármacos , Avaliação Pré-Clínica de Medicamentos , Sinergismo Farmacológico , Humanos , Masculino , Nitrilas/administração & dosagem , Nitrilas/farmacologia , Coativador 2 de Receptor Nuclear/metabolismo , Óxidos/administração & dosagem , Neoplasias da Próstata/patologia , Ligação Proteica/efeitos dos fármacos , Estrutura Terciária de Proteína , Transporte Proteico/efeitos dos fármacos , Receptores Androgênicos/química , Receptores Androgênicos/metabolismo , Receptores Androgênicos/fisiologia , Elementos de Resposta/fisiologia , Compostos de Tosil/administração & dosagem , Compostos de Tosil/farmacologia , Células Tumorais CultivadasRESUMO
Increasing evidence suggests that androgen independent prostate cancer (PC) maintains a functional androgen receptor (AR) pathway despite the low levels of circulating androgen following androgen withdrawal, the molecular mechanisms of which are not well defined yet. To address this question, we investigated the effects of endothelin-1 (ET-1) on AR expression. Western analysis and RT-PCR revealed that in the presence of ET-1, levels of AR significantly increased in a time- and dose-dependent manner in LNCaP cells. Pretreatments with inhibitors of Src and phosphoinositide kinase 3 (PI-3K) suppressed ET-1-induced AR expression. As ET-1 was reported to cause a transient increase in c-myc mRNA levels, we examined the involvement of c-myc in ET-1-mediated AR expression. Transient transfection of c-myc siRNA neutralized ET-1-induced AR expression, suggesting that AR induction by ET-1 is c-myc dependent. AR can regulate the transcription of its own gene via a mechanism in which c-myc plays a crucial role. Therefore, we assessed if ET-1-induced-c-myc leads to the enhancement of AR transcription. Reporter gene assays using the previously identified AR gene enhancer containing a c-myc binding site were conducted in LNCaP cells. We found that ET-1 induced reporter gene activity from the construct containing the wild-type but not mutant c-myc binding site. Chromatin immunoprecipitation assays confirmed that ET-1 increased interaction between c-myc and c-myc binding sites in AR enhancer, suggesting that ET-1-induced AR transcription occurs via c-myc-mediated AR transcription. Together, these data support the notion that ET-1, via Src/PI-3K signaling, augments c-myc expression leading to enhanced AR expression in PC.
Assuntos
Endotelina-1/fisiologia , Genes myc , Neoplasias da Próstata/metabolismo , Receptores Androgênicos/metabolismo , Sequência de Bases , Western Blotting , Linhagem Celular Tumoral , Imunoprecipitação da Cromatina , Primers do DNA , Humanos , Masculino , Fosfatidilinositol 3-Quinases/metabolismo , Neoplasias da Próstata/genética , Neoplasias da Próstata/patologia , Receptores Androgênicos/genética , Reação em Cadeia da Polimerase Via Transcriptase ReversaRESUMO
Prostate cancer invariably recurs after androgen deprivation therapy. Growth of this recurrent/androgen-independent form of prostate cancer may be due to increased androgen receptor (AR) transcriptional activity in the absence of androgen. This ligand-independent AR activation is promoted by some growth factors but the mechanism is not well understood. Vav3, a Rho guanosine triphosphatase guanine nucleotide exchange factor, which is activated by growth factors, is up-regulated in human prostate cancer. We show here that Vav3 levels increase during in vivo progression of prostate cancer to androgen independence. Vav3 strikingly enhanced growth factor activation of AR in the absence of androgen. Because Vav3 may be chronically activated in prostate cancer by growth factor receptors, we examined the effects of a constitutively active (Ca) form of Vav3 on AR transcriptional activity. Ca Vav3 caused nuclear localization and ligand-independent activation of AR via the Rho guanosine triphosphatase, Rac1. Ca Rac1 activation of AR occurred, in part, through MAPK/ERK signaling. Expression of active Rac1 conferred androgen-independent growth of prostate cancer cells in culture, soft agar, and mice. These findings suggest that Vav3/Rac 1 signaling is an important modulator of ligand-independent AR transcriptional activity in prostate cancer progression.
Assuntos
Fatores de Troca do Nucleotídeo Guanina/metabolismo , Neoplasias Hormônio-Dependentes/metabolismo , Neoplasias da Próstata/metabolismo , Proteínas Proto-Oncogênicas c-vav/metabolismo , Receptores Androgênicos/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Animais , Linhagem Celular Tumoral , Fatores de Troca do Nucleotídeo Guanina/biossíntese , Fatores de Troca do Nucleotídeo Guanina/genética , Humanos , Sistema de Sinalização das MAP Quinases , Masculino , Camundongos , Camundongos Nus , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Transplante de Neoplasias , Neoplasias Hormônio-Dependentes/enzimologia , Neoplasias da Próstata/enzimologia , Proteínas Proto-Oncogênicas c-vav/biossíntese , Proteínas Proto-Oncogênicas c-vav/genética , RNA Mensageiro/biossíntese , RNA Mensageiro/genética , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Transdução de Sinais , Transcrição Gênica , Transplante Heterólogo , Regulação para Cima , Proteínas rac1 de Ligação ao GTP/biossíntese , Proteínas rac1 de Ligação ao GTP/genéticaRESUMO
Castration-resistant prostate cancer (CRPC) recurs after androgen deprivation therapy (ADT) and is incurable. Reactivation of androgen receptor (AR) signaling in the low androgen environment of ADT drives CRPC. This AR activity occurs through a variety of mechanisms, including up-regulation of AR coactivators such as VAV3 and expression of constitutively active AR variants such as the clinically relevant AR-V7. AR-V7 lacks a ligand-binding domain and is linked to poor prognosis. We previously showed that VAV3 enhances AR-V7 activity to drive CRPC progression. Gene expression profiling after depletion of either VAV3 or AR-V7 in CRPC cells revealed arginine vasopressin receptor 1a (AVPR1A) as the most commonly down-regulated gene, indicating that this G protein-coupled receptor may be critical for CRPC. Analysis of publicly available human PC datasets showed that AVPR1A has a higher copy number and increased amounts of mRNA in advanced PC. Depletion of AVPR1A in CRPC cells resulted in decreased cell proliferation and reduced cyclin A. In contrast, androgen-dependent PC, AR-negative PC, or nontumorigenic prostate epithelial cells, which have undetectable AVPR1A mRNA, were minimally affected by AVPR1A depletion. Ectopic expression of AVPR1A in androgen-dependent PC cells conferred castration resistance in vitro and in vivo. Furthermore, treatment of CRPC cells with the AVPR1A ligand, arginine vasopressin (AVP), activated ERK and CREB, known promoters of PC progression. A clinically safe and selective AVPR1A antagonist, relcovaptan, prevented CRPC emergence and decreased CRPC orthotopic and bone metastatic growth in mouse models. Based on these preclinical findings, repurposing AVPR1A antagonists is a promising therapeutic approach for CRPC.
Assuntos
Terapia de Alvo Molecular , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Receptores de Vasopressinas/metabolismo , Animais , Cálcio/metabolismo , Linhagem Celular Tumoral , Proliferação de Células/genética , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/metabolismo , Resistencia a Medicamentos Antineoplásicos/genética , Regulação Neoplásica da Expressão Gênica , Humanos , Indóis/farmacologia , Indóis/uso terapêutico , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Masculino , Camundongos Nus , Osteogênese/efeitos dos fármacos , Neoplasias de Próstata Resistentes à Castração/genética , Neoplasias de Próstata Resistentes à Castração/patologia , Proteínas Proto-Oncogênicas c-vav/metabolismo , Pirrolidinas/farmacologia , Pirrolidinas/uso terapêutico , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Androgênicos/metabolismo , Receptores de Vasopressinas/genéticaRESUMO
Most prostate cancer cases remain indolent for long periods of time, but metastatic progression quickly worsens the prognosis and leads to mortality. However, little is known about what promotes the metastasis of prostate cancer and there is a lack of effective prognostic indicators, making it immensely difficult to manage options for treatment or surveillance. Arginyltransferase 1 (Ate1) is the enzyme mediating post-translational protein arginylation, which has recently been identified as a master regulator affecting many cancer-relevant pathways including stress response, cell cycle checkpoints, and cell migration/adhesion. However, the precise role of Ate1 in cancer remains unknown. In this study, we found the occurrence of metastasis of prostate cancer is inversely correlated with the levels of Ate1 protein and mRNA in the primary tumor. We also found that metastatic prostate cancer cell lines have a reduced level of Ate1 protein compared to non-metastatic cell lines, and that a depletion of Ate1 drives prostate cancer cells towards more aggressive pro-metastatic phenotypes without affecting proliferation rates. Furthermore, we demonstrated that a reduction of Ate1 can result from chronic stress, and that shRNA-reduced Ate1 increases cellular resistance to stress, and drives spontaneous and stress-induced genomic mutations. Finally, by using a prostate orthotropic xenograft mouse model, we found that a reduction of Ate1 was sufficient to enhance the metastatic phenotypes of prostate cancer cell line PC-3 in vivo. Our study revealed a novel role of Ate1 in suppressing prostate cancer metastasis, which has a profound significance for establishing metastatic indicators for prostate cancer, and for finding potential treatments to prevent its metastasis.
Assuntos
Aminoaciltransferases/metabolismo , Movimento Celular , Proteínas de Neoplasias/metabolismo , Neoplasias da Próstata/enzimologia , Neoplasias da Próstata/metabolismo , Aminoaciltransferases/genética , Animais , Células HEK293 , Humanos , Masculino , Camundongos , Camundongos Knockout , Metástase Neoplásica , Proteínas de Neoplasias/genética , Prognóstico , Neoplasias da Próstata/diagnóstico , Neoplasias da Próstata/patologiaRESUMO
Chemotherapeutic drugs ideally should take advantage of the differences between transformed and normal cells and induce apoptosis only in cancer cells. One such difference may be the overexpression of cyclin B1 protein in cancer cells, which is required for the proper progression through mitosis. Previously, we showed that treatment of human prostate cancer cells with 2-methoxyestradiol (2-ME) or docetaxel results in an accumulation of cyclin B1 protein and an increase in cyclin B1 kinase activity, followed by induction of apoptotic cell death. Inhibition of cyclin B1 kinase lowers apoptosis induced by 2-ME and docetaxel. In this study, we established a positive correlation between cyclin B1 protein and apoptosis induced by chemotherapy in prostate cancer cells. There is minimal cyclin B1 and induction of apoptosis by chemotherapy in nontransformed cells. LNCaP and PC-3 prostate cancer cells stably overexpressing cyclin B1 are more sensitive to apoptosis induced by chemotherapy. LNCaP cells expressing cyclin B1 small interfering RNA to lower cyclin B1 protein or dominant negative cyclin-dependent kinase 1 to inhibit cyclin B1 kinase show a decrease in apoptosis. Increased sensitivity to apoptosis by overexpression of cyclin B1 may be due to lower Bcl-2, higher p53, and decreased neuroendocrine differentiation. We suggest that a cancer-specific mechanism whereby 2-ME and docetaxel may exert anti-prostate cancer activity is the deregulated activation of cyclin B1 kinase, leading to the induction of apoptotic cell death. Our results also suggest that higher levels of cyclin B1 in prostate cancer cells may be a good prognostic marker for chemotherapy.
Assuntos
Antineoplásicos/farmacologia , Apoptose , Ciclina B/biossíntese , Regulação Neoplásica da Expressão Gênica , Neoplasias/tratamento farmacológico , Neoplasias da Próstata/tratamento farmacológico , Neoplasias da Próstata/patologia , 2-Metoxiestradiol , Diferenciação Celular , Linhagem Celular Tumoral , Ciclina B1 , Docetaxel , Estradiol/análogos & derivados , Estradiol/farmacologia , Humanos , Masculino , Mitose , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , RNA Interferente Pequeno/metabolismo , Taxoides/farmacologiaRESUMO
CONTEXT: Although a number of studies have demonstrated the importance of constitutively active androgen receptor variants (AR-Vs) in prostate cancer, questions still remain about the precise role of AR-Vs in the progression of castration-resistant prostate cancer (CRPC). OBJECTIVE: Key stakeholders and opinion leaders in prostate cancer convened on May 11, 2017 in Boston to establish the current state of the field of AR-Vs. EVIDENCE ACQUISITION: The meeting "Mission Androgen Receptor Variants" was the second of its kind sponsored by the Prostate Cancer Foundation (PCF). This invitation-only event was attended by international leaders in the field and representatives from sponsoring organizations (PCF and industry sponsors). Eighteen faculty members gave short presentations, which were followed by in-depth discussions. Discussions focused on three thematic topics: (1) potential of AR-Vs as biomarkers of therapeutic resistance; (2) role of AR-Vs as functionally active CRPC progression drivers; and (3) utility of AR-Vs as therapeutic targets in CRPC. EVIDENCE SYNTHESIS: The three meeting organizers synthesized this meeting report, which is intended to summarize major data discussed at the meeting and identify key questions as well as strategies for addressing these questions. There was a critical consensus that further study of the AR-Vs is an important research focus in CRPC. Contrasting views and emphasis, each supported by data, were presented at the meeting, discussed among the participants, and synthesized in this report. CONCLUSIONS: This article highlights the state of knowledge and outlines the most pressing questions that need to be addressed to advance the AR-V field. PATIENT SUMMARY: Although further investigation is needed to delineate the role of androgen receptor (AR) variants in metastatic castration-resistant prostate cancer, advances in measurement science have enabled development of blood-based tests for treatment selection. Detection of AR variants (eg, AR-V7) identified a patient population with poor outcomes to existing AR-targeting therapies, highlighting the need for novel therapeutic agents currently under development.
Assuntos
Antagonistas de Androgênios/uso terapêutico , Feniltioidantoína/análogos & derivados , Neoplasias de Próstata Resistentes à Castração/tratamento farmacológico , Neoplasias de Próstata Resistentes à Castração/metabolismo , Receptores Androgênicos/sangue , Idoso , Androstenos/uso terapêutico , Benzamidas , Biomarcadores Tumorais/sangue , Congressos como Assunto , Intervalo Livre de Doença , Seguimentos , Humanos , Masculino , Pessoa de Meia-Idade , Nitrilas , Feniltioidantoína/uso terapêutico , Neoplasias de Próstata Resistentes à Castração/mortalidade , Medição de Risco , Análise de Sobrevida , Resultado do TratamentoRESUMO
The progression of prostate cancer from androgen dependence to androgen independence is often accompanied by enhanced androgen receptor (AR) transcriptional activity. We observed a marked increase in the expression of Vav3, a Rho GTPase guanine nucleotide exchange factor (GEF), during the progression of human prostate cancer LNCaP cells to the androgen-independent derivative, LNCaP-R1. GEFs activate Rho family GTPases by promoting the exchange of GDP for GTP. Reporter gene assays showed that Vav3 potentiated AR transcriptional activity, and knock down of Vav3 resulted in decreased AR transactivation. Vav3 also increased androgen-induced levels of prostate-specific antigen mRNA. Furthermore, Vav3 enhanced AR activity at subnanomolar concentrations of androgen. This finding is particularly relevant because low androgen levels may be present in prostate tissue of patients undergoing androgen deprivation therapy. Enhancement of AR activity by Vav3 required amino terminal activation function 1 (AF1) of AR; however, Vav3 did not interact with AR or increase AR levels. Neither GEF function nor the C-terminal domains of Vav3 were required for Vav3-mediated enhancement of AR activity; however, the pleckstrin homology domain was obligatory. These data show that Vav3 levels rise during progression to androgen independence and support continued AR signaling (even under conditions of low androgen) by a novel GEF-independent cross-talk mechanism.