Nutlin3a Contributes to the Cytoplasmic Retention of Androgen Receptor

Prostate cancer cells need androgens to grow and maintain like normal prostate cells, both utilize that Androgen Receptor (AR) function. Androgen receptor (AR) is expressed throughout the prostate cancer progression plays a critical role as a transcription factor in castration-dependent stages of disease. AR also interacts to many cellular proteins, including p53, to regulate apoptosis. Further, as the stabilization of p53 protein triggers apoptosis, p53 interacting small molecules such as Nutlin3a, are interpreted as cancer therapeutics. In this study, to find out how Nutlin3a-mediated p53 stabilization effect on AR signaling. Here, we investigated the dynamics of p53 binding to transcriptional targets of AR, and further investigated the variations of AR intracellular localization as well as transactivation in the presence of Nutlin3a. To do this, the changes in AR transactivation were investigated via luciferase reporter assay, which was performed by treating LNCaPs with different doses of Nutlin3a and resulted that transactivation was suppressed by Nutlin3a in a dose dependent manner. AR transactivation and sub-cellular localization were also studied by immunofluorescence assay and found that cytoplasmic-nuclear fractionation-coupled western blot analysis showed that Nutlin3a inhibits AR phosphorylation and nuclear translocation regardless of androgens.

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Use of nuclear androgen receptor status to predict early biochemical recurrence of prostate cancer patients

Journal of Clinical Oncology ◽

10.1200/jco.2007.25.18_suppl.21073 ◽

2007 ◽

Vol 25 (18_suppl) ◽

pp. 21073-21073

Author(s):

J. Diallo ◽

A. Aldejmah ◽

M. Alam Fahmy ◽

I. Koumakpayi ◽

A. Mes-Masson ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Early Onset ◽

Biochemical Recurrence ◽

Normal Tissue ◽

Cellular Localization ◽

Nuclear Staining ◽

Normal Prostate ◽

Kaplan Meier ◽

Hormone Sensitive

21073 Background: Prostate cancer (PCa) is a leading cause of cancer death in North American men. The androgen receptor (AR) has an established role in the progression of this disease; however, it is unclear at what stage it intervenes. It is also uncertain whether the AR can be a useful prognostic marker for PCa. In this study, we assessed AR expression and sub-cellular localization in normal prostate as well as in androgen sensitive and insensitive PCa (AIPCa) tissues, and evaluated the ability of the AR to predict biochemical recurrence (BCR). Methods: We used tissue micro-arrays containing prostate tissue cores obtained from cancer-free patients (n=43), AIPCa patients (n=36), and patients with hormone-sensitive cancers (n=64) from which were collected both cancerous and normal adjacent tissue. Using immmunohistochemistry, we stained the tissue micro-arrays with a monoclonal antibody recognizing the AR. Two observers assessed the frequency and intensity of both cytoplasmic and nuclear AR staining. AR cytoplasmic (Ci) and nuclear (Ni) indices were calculated by multiplying nuclear staining frequency and nuclear staining intensity. Kaplan Meier, and Cox multivariate analyses were done using SPSS. Results: We found that AR Ci increased significantly in AIPCa although a modest but significant increase in PCa Ci was observed compared to normal tissues. In contrast, AR Ni was significantly lower in cancer-free patients as opposed to that seen in normal tissue adjacent to cancer. Similarly, cancerous tissue exhibited higher AR Ni than its adjacent normal tissue (p<0.05, Kruskal-Wallis). Kaplan Meier analyses revealed that low AR Ni was predictive of an early onset of BCR (before 3-years) in the sub-cohort of hormone-sensitive patients (LR=6.51, p=0.011). Futhermore, low AR Ni remained an independent predictor of early BCR in a Cox multivariate model controlling for age, pre-operative PSA, lymph node invasion, Gleason score and surgical margin status (HR=2.28, 95% CI=1.04 - 5, p<0.05). Conclusions: We conclude that increased nuclear AR activity could be a pre-malignant step in PCa progression whereas its role within cancer cells may be more complex, as low AR nuclear activity was associated with early onset of BCR. No significant financial relationships to disclose.

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Leupaxin, a Novel Coactivator of the Androgen Receptor, Is Expressed in Prostate Cancer and Plays a Role in Adhesion and Invasion of Prostate Carcinoma Cells

Molecular Endocrinology ◽

10.1210/me.2006-0546 ◽

2008 ◽

Vol 22 (7) ◽

pp. 1606-1621 ◽

Cited By ~ 22

Author(s):

Silke Kaulfuss ◽

Michal Grzmil ◽

Bernhard Hemmerlein ◽

Paul Thelen ◽

Stefan Schweyer ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Nuclear Export ◽

Mutational Analysis ◽

Specific Antigen ◽

High Rate ◽

Dependent Manner ◽

Lncap Cells ◽

Normal Prostate ◽

Progression Marker

Abstract In the present study, we demonstrate that leupaxin mRNA is overexpressed in prostate cancer (PCa) as compared with normal prostate tissue by using cDNA arrays and quantitative RT-PCR analyses. Moderate to strong expression of leupaxin protein was detected in approximately 22% of the PCa tissue sections analyzed, and leupaxin expression intensities were found to be significantly correlated with Gleason patterns/scores. In addition, different leupaxin expression levels were observed in PCa cell lines, and at the subcellular level, leupaxin was usually localized in focal adhesion sites. Furthermore, mutational analysis and transfection experiments of LNCaP cells using different green fluorescent protein-leupaxin constructs demonstrated that leupaxin contains functional nuclear export signals in its LD3 and LD4 motifs, thus shuttling between the cytoplasm and the nucleus. We could also demonstrate for the first time that leupaxin interacts with the androgen receptor in a ligand-dependent manner and serves as a transcriptional activator of this hormone receptor in PCa cells. Down-regulation of leupaxin expression using RNA interference in LNCaP cells resulted in a high rate of morphological changes, detachment, spontaneous apoptosis, and a reduction of prostate-specific antigen secretion. In contrast, knockdown of leupaxin expression in androgen-independent PC-3 and DU 145 cells induced a significant decrease of both the invasive capacity and motility. Our results therefore indicate that leupaxin could serve as a potential progression marker for a subset of PCa and may represent a novel coactivator of the androgen receptor. Leupaxin could function as a putative target for therapeutic interventions of a subset of advanced PCa.

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Circular RNA cir-ITCH Is a Potential Therapeutic Target for the Treatment of Castration-Resistant Prostate Cancer

BioMed Research International ◽

10.1155/2020/7586521 ◽

2020 ◽

Vol 2020 ◽

pp. 1-9

Author(s):

Shoubin Li ◽

Chunhong Yu ◽

Yunxia Zhang ◽

Junjiang Liu ◽

Yi Jia ◽

...

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cell Lines ◽

Therapeutic Target ◽

Critical Role ◽

Circular Rna ◽

Migration And Invasion ◽

Castration Resistant Prostate Cancer ◽

Normal Prostate ◽

Castration Resistant

cir-ITCH, a well-known tumor-suppressive circular RNA, plays a critical role in different cancers. However, its expression and functional role in prostate cancer (PCa) are unclear. Herein, we explored the potential mechanism and tumor-inhibiting role of cir-ITCH in PCa. Using reverse transcriptase polymerase chain reaction assay, we analyzed the expression of cir-ITCH in PCa and paired adjacent nontumor tissue samples resected during surgical operation, as well as in two cell lines of human PCa (LNCaP and PC-3) and the immortalized normal prostate epithelial cell line (RWPE-1). Cell viability and migration of PCa cell lines were evaluated using CCK-8 and wound-healing assays. Expression of key proteins of the Wnt/β-catenin and PI3K/AKT/mTOR pathways was detected using western blotting. We found that cir-ITCH expression was typically downregulated in the tissues and cell lines of PCa compared to that in the peritumoral tissue and in RWPE-1 cells, respectively. The results showed that cir-ITCH overexpression significantly inhibits the proliferation, migration, and invasion of human PCa cells and that reciprocal inhibition of expression occurred between cir-ITCH and miR-17. Proteins in the Wnt/β-catenin and PI3K/AKT/mTOR pathways were downregulated by overexpression of cir-ITCH both in androgen receptor-positive LNCaP cells and androgen receptor-negative PC-3 cells. Taken together, these data demonstrated that cir-ITCH plays a tumor-suppressive role in human PCa cells, partly through the Wnt/β-catenin and PI3K/AKT/mTOR pathways. Thus, cir-ITCH may serve as a novel therapeutic target for the treatment of PCa, especially castration-resistant prostate cancer.

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Acacetin Inhibits the Growth of STAT3-Activated DU145 Prostate Cancer Cells by Directly Binding to Signal Transducer and Activator of Transcription 3 (STAT3)

Molecules ◽

10.3390/molecules26206204 ◽

2021 ◽

Vol 26 (20) ◽

pp. 6204

Author(s):

Sun Yun ◽

Yu-Jin Lee ◽

Jiyeon Choi ◽

Nam Doo Kim ◽

Dong Cho Han ◽

...

Keyword(s):

Prostate Cancer ◽

Cancer Cells ◽

Nuclear Translocation ◽

Critical Role ◽

Cancer Drug ◽

Dependent Manner ◽

Signal Transducer ◽

Prostate Cancer Cells ◽

Stat3 Phosphorylation ◽

Transcription 3

Signal transducer and activator of transcription 3 (STAT3) plays a critical role in the formation and growth of human cancer. Therefore, STAT3 is a therapeutic target for cancer drug discovery. Acacetin, a flavone present in various plants, inhibits constitutive and inducible STAT3 activation in STAT3-activated DU145 prostate cancer cells. Acacetin inhibits STAT3 activity by directly binding to STAT3, which we confirmed by a pull-down assay with a biotinylated compound and two level-free methods, namely, a drug affinity responsive target stability (DARTS) experiment and a cellular thermal shift assay (CETSA). Acacetin inhibits STAT3 phosphorylation at the tyrosine 705 residue and nuclear translocation in DU145 cells, which leads to the downregulation of STAT3 target genes. Acacetin then induces apoptosis in a time-dependent manner. Interestingly, acacetin induces the production of reactive oxygen species (ROS) that are not involved in the acacetin-induced inhibition of STAT3 activation because the suppressed p-STAT3 level is not rescued by treatment with GSH or NAC, which are general ROS inhibitors. We also found that acacetin inhibits tumor growth in xenografted nude mice. These results suggest that acacetin, as a STAT3 inhibitor, could be a possible drug candidate for targeting STAT3 for the treatment of cancer in humans.

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Interaction between androgen receptor and coregulator SLIRP is regulated by Ack1 tyrosine kinase and androgen

Scientific Reports ◽

10.1038/s41598-019-55057-2 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Dinuka De Silva ◽

Zhentao Zhang ◽

Yuanbo Liu ◽

Joel S. Parker ◽

Chenxi Xu ◽

...

Keyword(s):

Androgen Receptor ◽

Tyrosine Kinase ◽

Noncoding Rna ◽

Target Genes ◽

Rna Binding ◽

Nuclear Translocation ◽

Critical Role ◽

Dependent Manner ◽

Castration Resistant Prostate Cancer ◽

Stem Loop

AbstractAberrant activation of the androgen receptor (AR) may play a critical role in castration resistant prostate cancer. After ligand binding, AR is recruited to the androgen responsive element (ARE) sequences on the DNA where AR interaction with coactivators and corepressors modulates transcription. We demonstrated that phosphorylation of AR at Tyr-267 by Ack1/TNK2 tyrosine kinase results in nuclear translocation, DNA binding, and androgen-dependent gene transcription in a low androgen environment. In order to dissect downstream mechanisms, we searched for proteins whose interaction with AR was regulated by Ack1. SLIRP (SRA stem-loop interacting RNA binding protein) was identified as a candidate protein. Interaction between AR and SLIRP was disrupted by Ack1 kinase activity as well as androgen or heregulin treatment. The noncoding RNA, SRA, was required for AR-SLIRP interaction. SLIRP was bound to ARE’s of AR target genes in the absence of androgen. Treatment with androgen or heregulin led to dissociation of SLIRP from the ARE. Whole transcriptome analysis of SLIRP knockdown in androgen responsive LNCaP cells showed that SLIRP affects a significant subset of androgen-regulated genes. Our data suggest that Ack1 kinase and androgen regulate interaction between AR and SLIRP and that SLIRP functions as a coregulator of AR with properties of a corepressor in a context-dependent manner.

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Interplay Between SOX9, Wnt/β-Catenin and Androgen Receptor Signaling in Castration-Resistant Prostate Cancer

International Journal of Molecular Sciences ◽

10.3390/ijms20092066 ◽

2019 ◽

Vol 20 (9) ◽

pp. 2066 ◽

Cited By ~ 12

Author(s):

Namrata Khurana ◽

Suresh C. Sikka

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Signaling Pathways ◽

Critical Role ◽

Castration Resistant Prostate Cancer ◽

Form Complex ◽

Androgen Receptor Signaling ◽

Castration Resistant ◽

Signaling Axis

Androgen receptor (AR) signaling plays a key role not only in the initiation of prostate cancer (PCa) but also in its transition to aggressive and invasive castration-resistant prostate cancer (CRPC). However, the crosstalk of AR with other signaling pathways contributes significantly to the emergence and growth of CRPC. Wnt/β-catenin signaling facilitates ductal morphogenesis in fetal prostate and its anomalous expression has been linked with PCa. β-catenin has also been reported to form complex with AR and thus augment AR signaling in PCa. The transcription factor SOX9 has been shown to be the driving force of aggressive and invasive PCa cells and regulate AR expression in PCa cells. Furthermore, SOX9 has also been shown to propel PCa by the reactivation of Wnt/β-catenin signaling. In this review, we discuss the critical role of SOX9/AR/Wnt/β-catenin signaling axis in the development and progression of CRPC. The phytochemicals like sulforaphane and curcumin that can concurrently target SOX9, AR and Wnt/β-catenin signaling pathways in PCa may thus be beneficial in the chemoprevention of PCa.

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Cytostatic Action of Novel Histone Deacetylase Inhibitors in Androgen Receptor-Null Prostate Cancer Cells

Pharmaceuticals ◽

10.3390/ph14020103 ◽

2021 ◽

Vol 14 (2) ◽

pp. 103

Author(s):

Zohaib Rana ◽

Joel D. A. Tyndall ◽

Muhammad Hanif ◽

Christian G. Hartinger ◽

Rhonda J. Rosengren

Keyword(s):

Prostate Cancer ◽

Androgen Receptor ◽

Cancer Cells ◽

Hdac Inhibitors ◽

G1 Arrest ◽

Prostate Cancer Cells ◽

Prostate Tumors ◽

Normal Prostate ◽

Pc3 Cells ◽

Du145 Cells

Androgen receptor (AR)-null prostate tumors have been observed in 11–24% of patients. Histone deacetylases (HDACs) are overexpressed in prostate tumors. Therefore, HDAC inhibitors (Jazz90 and Jazz167) were examined in AR-null prostate cancer cell lines (PC3 and DU145). Both Jazz90 and Jazz167 inhibited the growth of PC3 and DU145 cells. Jazz90 and Jazz167 were more active in PC3 cells and DU145 cells in comparison to normal prostate cells (PNT1A) and showed a 2.45- and 1.30-fold selectivity and higher cytotoxicity toward DU145 cells, respectively. Jazz90 and Jazz167 reduced HDAC activity by ~60% at 50 nM in PC3 lysates. At 4 μM, Jazz90 and Jazz167 increased acetylation in PC3 cells by 6- to 8-fold. Flow cytometry studies on the cell phase distribution demonstrated that Jazz90 causes a G0/G1 arrest in AR-null cells, whereas Jazz167 leads to a G0/G1 arrest in DU145 cells. However, apoptosis only occurred at a maximum of 7% of the total cell population following compound treatments in PC3 and DU145 cells. There was a reduction in cyclin D1 and no significant changes in bcl-2 in DU145 and PC3 cells. Overall, the results showed that Jazz90 and Jazz167 function as cytostatic HDAC inhibitors in AR-null prostate cancer cells.

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Norepinephrine induces calcium spikes and proinflammatory actions in human hepatic stellate cells

AJP Gastrointestinal and Liver Physiology ◽

10.1152/ajpgi.00537.2005 ◽

2006 ◽

Vol 291 (5) ◽

pp. G877-G884 ◽

Cited By ~ 38

Author(s):

Pau Sancho-Bru ◽

Ramón Bataller ◽

Jordi Colmenero ◽

Xavier Gasull ◽

Montserrat Moreno ◽

...

Keyword(s):

Cell Proliferation ◽

Portal Hypertension ◽

Liver Fibrosis ◽

Hepatic Stellate Cells ◽

Molecular Mechanisms ◽

Nuclear Translocation ◽

Stellate Cells ◽

Luciferase Reporter ◽

Dependent Manner ◽

Cell Contraction

Catecholamines participate in the pathogenesis of portal hypertension and liver fibrosis through α1-adrenoceptors. However, the underlying cellular and molecular mechanisms are largely unknown. Here, we investigated the effects of norepinephrine (NE) on human hepatic stellate cells (HSC), which exert vasoactive, inflammatory, and fibrogenic actions in the injured liver. Adrenoceptor expression was assessed in human HSC by RT-PCR and immunocytochemistry. Intracellular Ca2+ concentration ([Ca2+]i) was studied in fura-2-loaded cells. Cell contraction was studied by assessing wrinkle formation and myosin light chain II (MLC II) phosphorylation. Cell proliferation and collagen-α1(I) expression were assessed by [3H]thymidine incorporation and quantitative PCR, respectively. NF-κB activation was assessed by luciferase reporter gene and p65 nuclear translocation. Chemokine secretion was assessed by ELISA. Normal human livers expressed α1A-adrenoceptors, which were markedly upregulated in livers with advanced fibrosis. Activated human HSC expressed α1A-adrenoceptors. NE induced multiple rapid [Ca2+]i oscillations (Ca2+ spikes). Prazosin (α1-blocker) completely prevented NE-induced Ca2+ spikes, whereas propranolol (nonspecific β-blocker) partially attenuated this effect. NE caused phosphorylation of MLC II and cell contraction. In contrast, NE did not affect cell proliferation or collagen-α1(I) expression. Importantly, NE stimulated the secretion of inflammatory chemokines (RANTES and interleukin-8) in a dose-dependent manner. Prazosin blocked NE-induced chemokine secretion. NE stimulated NF-κB activation. BAY 11-7082, a specific NF-κB inhibitor, blocked NE-induced chemokine secretion. We conclude that NE stimulates NF-κB and induces cell contraction and proinflammatory effects in human HSC. Catecholamines may participate in the pathogenesis of portal hypertension and liver fibrosis by targeting HSC.

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The role of the androgen receptor as a driver and mitigator of cellular stress

Journal of Molecular Endocrinology ◽

10.1530/jme-20-0057 ◽

2020 ◽

Vol 65 (2) ◽

pp. R19-R33

Author(s):

Dimitrios Doultsinos ◽

Ian Mills

Keyword(s):

Prostate Cancer ◽

Protein Synthesis ◽

Androgen Receptor ◽

Cancer Progression ◽

Prostate Gland ◽

Specific Antigen ◽

Nuclear Hormone Receptor ◽

Biological Processes ◽

Normal Prostate ◽

Mtor Activity

Prostate cancer is a high-incidence male cancer, which is dependent on the activity of a nuclear hormone receptor, the androgen receptor (AR). Since the AR is required for both normal prostate gland development and for prostate cancer progression, it is possible that prostate cancer evolves from perturbations in AR-dependent biological processes that sustain specialist glandular functions. The archetypal example of course is the use of prostate specific antigen (PSA), an organ-type specific component of the normal prostate secretome, as a biomarker of prostate cancer. Furthermore, localised prostate cancer is characterised by a low proliferative index and a heterogenous array of somatic mutations aligned to a multifocal disease pattern. We and others have identified a number of biological processes that are AR dependent and represent aberrations in significant glandular processes. Glands are characterised by high rates of metabolic activity including protein synthesis supported by co-dependent processes such as glycosylation, organelle biogenesis and vesicle trafficking. Impairments in anabolic metabolism and in protein folding/processing will inevitably impose proteotoxic and oxidative stress on glandular cells and, in particular, luminal epithelial cells for which secretion is their primary function. As cancer develops there is also significant metabolic dysregulation including impaired negative feedback effects on glycolytic and anabolic activity under conditions of hypoxia and heightened protein synthesis due to dysregulated PI 3-kinase/mTOR activity. In this review we will focus on the components of the AR regulome that support cancer development as well as glandular functions focussing on the unfolded protein response and on regulators of mTOR activity.

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Voruciclib, a Potent CDK4/6 Inhibitor, Antagonizes ABCB1 and ABCG2-Mediated Multi-Drug Resistance in Cancer Cells

Cellular Physiology and Biochemistry ◽

10.1159/000487578 ◽

2018 ◽

Vol 45 (4) ◽

pp. 1515-1528 ◽

Cited By ~ 27

Author(s):

Pranav Gupta ◽

Yun-Kai Zhang ◽

Xiao-Yu Zhang ◽

Yi-Jun Wang ◽

Kimberly W. Lu ◽

...

Keyword(s):

Atpase Activity ◽

Cellular Localization ◽

Intracellular Localization ◽

Scintillation Counter ◽

Flow Cytometric Analysis ◽

Multi Drug Resistance ◽

Dependent Manner ◽

Cancer Drugs ◽

Intracellular Accumulation ◽

Anti Cancer

Background/Aims: The overexpression of ATP-Binding Cassette (ABC) transporters has known to be one of the major obstacles impeding the success of chemotherapy in drug resistant cancers. In this study, we evaluated voruciclib, a CDK 4/6 inhibitor, for its chemo-sensitizing activity in ABCB1- and ABCG2- overexpressing cells. Methods: Cytotoxicity and reversal effect of voruciclib was determined by MTT assay. The intracellular accumulation and efflux of ABCB1 and ABCG2 substrates were measured by scintillation counter. The effects on expression and intracellular localization of ABCB1 and ABCG2 proteins were determined by Western blotting and immunofluorescence, respectively. Vanadate-sensitive ATPase assay was done to determine the effect of voruciclib on the ATPase activity of ABCB1 and ABCG2. Flow cytometric analysis was done to determine the effect of voruciclib on apoptosis of ABCB1 and ABCG2-overexpressing cells and docking analysis was done to determine the interaction of voruciclib with ABCB1 and ACBG2 protein. Results: Voruciclib significantly potentiated the effect of paclitaxel and doxorubicin in ABCB1-overexpressing cells, as well as mitoxantrone and SN-38 in ABCG2-overexpressing cells. Voruciclib moderately sensitized ABCC10- overexpressing cells to paclitaxel, whereas it did not alter the cytotoxicity of substrates of ABCC1. Furthermore, voruciclib increased the intracellular accumulation and decreased the efflux of substrate anti-cancer drugs from ABCB1- or ABCG2-overexpressing cells. However, voruciclib did not alter the expression or the sub-cellular localization of ABCB1 or ABCG2. Voruciclib stimulated the ATPase activity of both ABCB1 and ABCG2 in a concentration-dependent manner. Lastly, voruciclib exhibited a drug-induced apoptotic effect in ABCB1- or ABCG2- overexpressing cells. Conclusion: Voruciclib is currently a phase I clinical trial drug. Our findings strongly support its potential use in combination with conventional anti-cancer drugs for cancer chemotherapy.

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