scholarly journals RhoA as a Mediator of Clinically Relevant Androgen Action in Prostate Cancer Cells

2012 ◽  
Vol 26 (5) ◽  
pp. 716-735 ◽  
Author(s):  
Lucy J. Schmidt ◽  
Kelly Duncan ◽  
Neelu Yadav ◽  
Kevin M. Regan ◽  
Alissa R. Verone ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Protein Kinase ◽  
Actin Polymerization ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Coiled Coil ◽  
Small Gtpase ◽  
Expression Levels ◽  
Aggressive Disease ◽  
Androgen Regulation

Abstract Recently, we have identified serum response factor (SRF) as a mediator of clinically relevant androgen receptor (AR) action in prostate cancer (PCa). Genes that rely on SRF for androgen responsiveness represent a small fraction of androgen-regulated genes, but distinguish benign from malignant prostate, correlate with aggressive disease, and are associated with biochemical recurrence. Thus, understanding the mechanism(s) by which SRF conveys androgen regulation to its target genes may provide novel opportunities to target clinically relevant androgen signaling. Here, we show that the small GTPase ras homolog family member A (RhoA) mediates androgen-responsiveness of more than half of SRF target genes. Interference with expression of RhoA, activity of the RhoA effector Rho-associated coiled-coil containing protein kinase 1 (ROCK), and actin polymerization necessary for nuclear translocation of the SRF cofactor megakaryocytic acute leukemia (MAL) prevented full androgen regulation of SRF target genes. Androgen treatment induced RhoA activation, increased the nuclear content of MAL, and led to MAL recruitment to the promoter of the SRF target gene FHL2. In clinical specimens RhoA expression was higher in PCa cells than benign prostate cells, and elevated RhoA expression levels were associated with aggressive disease features and decreased disease-free survival after radical prostatectomy. Overexpression of RhoA markedly increased the androgen-responsiveness of select SRF target genes, in a manner that depends on its GTPase activity. The use of isogenic cell lines and a xenograft model that mimics the transition from androgen-stimulated to castration-recurrent PCa indicated that RhoA levels are not altered during disease progression, suggesting that RhoA expression levels in the primary tumor determine disease aggressiveness. Androgen-responsiveness of SRF target genes in castration-recurrent PCa cells continued to rely on AR, RhoA, SRF, and MAL and the presence of intact SRF binding sites. Silencing of RhoA, use of Rho-associated coiled-coil containing protein kinase 1 inhibitors, or an inhibitor of SRF-MAL interaction attenuated (androgen-regulated) cell viability and blunted PCa cell migration. Taken together, these studies demonstrate that the RhoA signaling axis mediates clinically relevant AR action in PCa.

Abstract A8: Androgen regulation of SRF target genes in prostate cancer cells is mediated in part by the small GTPase RhoA

2012 ◽  
Vol 72 (4 Supplement) ◽  
pp. A8-A8
Author(s):  
Lucy Schmidt ◽  
Thomas Sebo ◽  
Donald Tindall ◽  
Hannelore Heemers ◽  
Kelly Duncan ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Cancer Cells ◽  
Target Genes ◽  
Small Gtpase ◽  
Prostate Cancer Cells ◽  
Androgen Regulation

Protein Kinase A phosphorylates NCoR to enhance its nuclear translocation and repressive function in human prostate cancer cells

2013 ◽  
Vol 228 (6) ◽  
pp. 1159-1165 ◽  
Author(s):  
Hyo-Kyoung Choi ◽  
Jung-Yoon Yoo ◽  
Mi-Hyeon Jeong ◽  
Soo-Yeon Park ◽  
Dong-Myoung Shin ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Cancer Cells ◽  
Nuclear Translocation ◽  
Human Prostate ◽  
Human Prostate Cancer ◽  
Prostate Cancer Cells ◽  
Kinase A

scholarly journals A Splicing Variant of the Androgen Receptor Detected in a Metastatic Prostate Cancer Exhibits Exclusively Cytoplasmic Actions

Endocrinology ◽  
2007 ◽  
Vol 148 (9) ◽  
pp. 4334-4343 ◽  
Author(s):  
Monika Jagla ◽  
Marie Fève ◽  
Pascal Kessler ◽  
Gaëlle Lapouge ◽  
Eva Erdmann ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Dna Binding ◽  
Cancer Progression ◽  
Metastatic Prostate Cancer ◽  
Transcriptional Activity ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Splicing Variant ◽  
Activation Of Transcription

The androgen receptor (AR) is a ligand-activated transcription factor that displays genomic actions characterized by binding to androgen-response elements in the promoter of target genes as well as nongenomic actions that do not require nuclear translocation and DNA binding. In this study, we report exclusive cytoplasmic actions of a splicing variant of the AR detected in a metastatic prostate cancer. This AR variant, named AR23, results from an aberrant splicing of intron 2, wherein the last 69 nucleotides of the intronic sequence are retained, leading to the insertion of 23 amino acids between the two zinc fingers in the DNA-binding domain. We show that the nuclear entry of AR23 upon dihydrotestosterone (DHT) stimulation is impaired. Alternatively, DHT-activated AR23 forms cytoplasmic and perinuclear aggregates that partially colocalize with the endoplasmic reticulum and are devoid of genomic actions. However, in LNCaP cells, this cytoplasmic DHT-activated AR23 remains partially active as evidenced by the activation of transcription from androgen-responsive promoters, the stimulation of NF-κB transcriptional activity and by the decrease of AP-1 transcriptional activity. Our data reveal novel cytoplasmic actions for this splicing AR variant, suggesting a contribution in prostate cancer progression.

scholarly journals Activation of GPR56, a novel adhesion GPCR, is necessary for nuclear androgen receptor signaling in prostate cells

2019 ◽  
Author(s):  
Julie Pratibha Singh ◽  
Manisha Dagar ◽  
Gunjan Dagar ◽  
Sudhir Rawal ◽  
Ravi Datta Sharma ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Androgen Receptor ◽  
Intracellular Signaling ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Prostate Tumor ◽  
Castration Resistant Prostate Cancer ◽  
Castration Resistant ◽  
Pka Pathway ◽  
Adhesion Gpcr

AbstractThe androgen receptor (AR) is activated in patients with castration resistant prostate cancer (CRPC) despite low circulating levels of androgen, suggesting that intracellular signaling pathways and non-androgenic factors may contribute to AR activation. Many G-protein coupled receptors (GPCR) and their ligands are also activated in these cells indicating a role for these in CRPC. Although a cross talk has been suggested between the two pathways, yet, the identity of GPCRs which may play a role in androgen signaling, is not established yet. We demonstrate that adhesion GPCR 205, also known as GPR56, can be activated by androgens to stimulate the Rho signaling pathway, a pathway that plays an important role in prostate tumor cell metastasis. Testosterone stimulation of GPR56 also activates the cAMP/ Protein kinase A (PKA) pathway, that is necessary for AR signaling. Knocking down the expression of GPR56 using siRNA, disrupts nuclear translocation of AR and transcription of prototypic AR target genes such as PSA. GPR56 expression is higher in all prostate tumor samples tested and cells expressing GPR56 exhibit increased proliferation. These findings provide new insights about androgen signaling and identify GPR56 as a possible therapeutic target in advanced prostate cancer patients.

scholarly journals Evodiamine Mitigates Cellular Growth and Promotes Apoptosis by Targeting the c-Met Pathway in Prostate Cancer Cells

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1320 ◽  
Author(s):  
Sun Tae Hwang ◽  
Jae-Young Um ◽  
Arunachalam Chinnathambi ◽  
Sulaiman Ali Alharbi ◽  
Acharan S. Narula ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Growth Factor ◽  
Protein Kinase ◽  
B Cell ◽  
Nuclear Translocation ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cellular Growth ◽  
Stat3 Phosphorylation ◽  
Du145 Cells

Evodiamine (EVO) is an indoloquinazoline alkaloid that exerts its various anti-oncogenic actions by blocking phosphatidylinositol-3-kinase/protein kinase B (PI3K/Akt), mitogen-activated protein kinase (MAPK), c-Met, and nuclear factor kappa B (NF-κB) signaling pathways, thus leading to apoptosis of tumor cells. We investigated the ability of EVO to affect hepatocyte growth factor (HGF)-induced c-Met/Src/STAT3 activation cascades in castration-resistant prostate cancer (CRPC). First, we noted that EVO showed cytotoxicity and anti-proliferation activities in PC-3 and DU145 cells. Next, we found that EVO markedly inhibited HGF-induced c-Met/Src/STAT3 phosphorylation and impaired the nuclear translocation of STAT3 protein. Then, we noted that EVO arrested the cell cycle, caused apoptosis, and downregulated the expression of various carcinogenic markers such as B-cell lymphoma 2 (Bcl-2), B-cell lymphoma-extra large (Bcl-xL), cyclin D1, cyclooxygenase 2 (COX-2), survivin, vascular endothelial growth factor (VEGF), and matrix metallopeptidases 9 (MMP-9). Moreover, it was observed that in cPC-3 and DU145 cells transfected with c-Met small interfering RNA (siRNA), Src/STAT3 activation was also mitigated and led to a decrease in EVO-induced apoptotic cell death. According to our results, EVO can abrogate the activation of the c-Met/Src/STAT3 signaling axis and thus plays a role as a robust suppressor of tumor cell survival, proliferation, and angiogenesis.

scholarly journals Airway smooth muscle tone increases actin filamentogenesis and contractile capacity

2020 ◽  
Vol 318 (2) ◽  
pp. L442-L451
Author(s):  
Morgan Gazzola ◽  
Cyndi Henry ◽  
Katherine Lortie ◽  
Fatemeh Khadangi ◽  
Chan Young Park ◽  
...  
Keyword(s):  
Smooth Muscle ◽  
Protein Kinase ◽  
Airway Smooth Muscle ◽  
Light Chain ◽  
Actin Filaments ◽  
Actin Polymerization ◽  
Molecular Mechanisms ◽  
Muscle Tone ◽  
Coiled Coil ◽  
Traction Force

Force adaptation of airway smooth muscle (ASM) is a process whereby the presence of tone (i.e., a sustained contraction) increases the contractile capacity. For example, tone has been shown to increase airway responsiveness in both healthy mice and humans. The goal of the present study is to elucidate the underlying molecular mechanisms. The maximal force generated by mouse tracheas was measured in response to 10−4 M of methacholine following a 30-min period with or without tone elicited by the EC30 of methacholine. To confirm the occurrence of force adaptation at the cellular level, traction force generated by cultured human ASM cells was also measured following a similar protocol. Different pharmacological inhibitors were used to investigate the role of Rho-associated coiled-coil containing protein kinase (ROCK), protein kinase C (PKC), myosin light chain kinase (MLCK), and actin polymerization in force adaptation. The phosphorylation level of the regulatory light chain (RLC) of myosin, the amount of actin filaments, and the activation level of the actin-severing protein cofilin were also quantified. Although ROCK, PKC, MLCK, and RLC phosphorylation was not implicated, force adaptation was prevented by inhibiting actin polymerization. Interestingly, the presence of tone blocked the activation of cofilin in addition to increasing the amount of actin filaments to a maximal level. We conclude that actin filamentogenesis induced by tone, resulting from both actin polymerization and the prevention of cofilin-mediated actin cleavage, is the main molecular mechanism underlying force adaptation.

scholarly journals NEMO oligomerization and its ubiquitin-binding properties

2009 ◽  
Vol 421 (2) ◽  
pp. 243-251 ◽  
Author(s):  
Frank J. Ivins ◽  
Mark G. Montgomery ◽  
Susan J. M. Smith ◽  
Aylin C. Morris-Davies ◽  
Ian A. Taylor ◽  
...  
Keyword(s):  
Leucine Zipper ◽  
Target Genes ◽  
Nuclear Translocation ◽  
Coiled Coil ◽  
Nuclear Factor Κb ◽  
Regulatory Subunit ◽  
Activation Process ◽  
Oligomeric State ◽  
Coiled Coil Region ◽  
Ikk Complex

The IKK [IκB (inhibitory κB) kinase] complex is a key regulatory component of NF-κB (nuclear factor κB) activation and is responsible for mediating the degradation of IκB, thereby allowing nuclear translocation of NF-κB and transcription of target genes. NEMO (NF-κB essential modulator), the regulatory subunit of the IKK complex, plays a pivotal role in this process by integrating upstream signals, in particular the recognition of polyubiquitin chains, and relaying these to the activation of IKKα and IKKβ, the catalytic subunits of the IKK complex. The oligomeric state of NEMO is controversial and the mechanism by which it regulates activation of the IKK complex is poorly understood. Using a combination of hydrodynamic techniques we now show that apo-NEMO is a highly elongated, dimeric protein that is in weak equilibrium with a tetrameric assembly. Interaction with peptides derived from IKKβ disrupts formation of the tetrameric NEMO complex, indicating that interaction with IKKα and IKKβ and tetramerization are mutually exclusive. Furthermore, we show that NEMO binds to linear di-ubiquitin with a stoichiometry of one molecule of di-ubiquitin per NEMO dimer. This stoichiometry is preserved in a construct comprising the second coiled-coil region and the leucine zipper and in one that essentially spans the full-length protein. However, our data show that at high di-ubiquitin concentrations a second weaker binding site becomes apparent, implying that two different NEMO–di-ubiquitin complexes are formed during the IKK activation process. We propose that the role of these two complexes is to provide a threshold for activation, thereby ensuring sufficient specificity during NF-κB signalling.

scholarly journals Hsa-miR-1-2/miR-133a-1 Cluster Expression Silencing by DNA Hypermethylation Triggers Oncogenes Contributing to Prostate Cancer Aggressiveness

2021 ◽  
Author(s):  
Cintia Massillo ◽  
Rocío Belén Duca ◽  
Paula Lucía Farré ◽  
Kevin Gardner ◽  
Ezequiel Lacunza ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Mirna Expression ◽  
Target Genes ◽  
Dietary Habits ◽  
Promoter Hypermethylation ◽  
Clinicopathological Features ◽  
Prostate Tumors ◽  
Expression Levels ◽  
Cancer Aggressiveness ◽  
Incidence And Mortality

Abstract Background: Prostate cancer (PCa) is currently the most commonly diagnosed type of cancer. The incidence and mortality of PCa worldwide correlate with increasing age and bad dietary habits. Previously, we investigated the mRNA/miRNA role on PCa development and progression using high fat diet (HFD) chronically fed mice models. Here our main goal was to investigate the effect of HFD on the expression of prostate cancer-related miRNAs and their relevance in PCa patients. Methods: Using microarray data from mice prostate tumors generated by TRAMP-C1 cell inoculation, we focused on the role of three candidate miRNAs (miR-133a-3p/133b/1-3p) and their target genes. Based on data from public databases, we examined the expression levels of hsa-miR-133a-3p/133b/1-3p and their correlation with clinicopathological features in PCa patients. The biological roles of hsa-miR-133a-3p/133b/1-3p and their relevant target genes were investigated by bioinformatics approaches. The promoter methylation of hsa-miR-133a-3p/133b/1-3p host genes and their correlation with mature miRNA expression was further evaluated.Results: We identified 6 up- and 18 down-regulated miRNAs in TRAMP-C1 mice prostate tumors under HFD conditions using miRNA microarrays. Target genes (1,278) of down-regulated miRNAs involved in cancer-related biological processes were identified using DIANA-TarBase and STRING databases. Three down-regulated miRNAs: hsa-miR-133a-3p, 133b and 1a-3p showed nine common target genes that negatively correlated with miRNA expression in prostate tumors from patients. Hsa-miR-133a-3p/133b/1-3p expression levels were significantly decreased in PCa compared to normal tissues and their low expression correlated with bad clinicopathological features in patients. We also examined the promoter region of hsa-miR-133a-3p/133b/1-3p encoding genes in PCa patients and then compared methylation at these loci with mature miRNA expression. This analysis revealed that hsa-miR-1-2/miR-133a-1 cluster promoter hypermethylation decreased hsa-miR-133a-3p/1-3p expression in prostate tumors. Furthermore, CENPF and WHSC1, two common hsa-miR-133a-3p/133b/1-3p target genes, were found significantly up-regulated in PCa and positively correlated with advanced clinicopathological characteristics in PCa patients.Conclusion: Our results provide an explanation for the aggressiveness of PCa and link it mechanistically to the attenuation of hsa-miR-133a-3p/133b/1-3p expression by promoter hypermethylation. Hsa-miR-133a-3p/133b/1-3p downregulation may enhance PCa aggressiveness in part by targeting CENPF and WHSC1. Therefore, hsa-miR-133a-3p/133b/1-3p might be potential therapeutic targets for lethal PCa.

scholarly journals MiR-34a regulates blood–tumor barrier function by targeting protein kinase Cε

2015 ◽  
Vol 26 (10) ◽  
pp. 1786-1796 ◽  
Author(s):  
Wei Zhao ◽  
Ping Wang ◽  
Jun Ma ◽  
Yun-Hui Liu ◽  
Zhen Li ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Protein Kinase ◽  
Protein Expression ◽  
Tight Junction ◽  
Target Genes ◽  
Vascular Endothelial Cells ◽  
Luciferase Reporter ◽  
Luciferase Reporter Gene ◽  
Expression Levels ◽  
Related Proteins

MicroRNA-34a (miR-34a) functions to regulate protein expression at the posttranscriptional level by binding the 3′ UTR of target genes and regulates functions of vascular endothelial cells. However, the role of miR-34a in regulating blood–tumor barrier (BTB) permeability remains unknown. In this study, we show that miR-34a overexpression leads to significantly increased permeability of BTB, whereas miR-34a silencing reduces the permeability of the BTB. In addition, miR-34a overexpression significantly down-regulates the expression and distribution of tight junction–related proteins in glioma endothelial cells (GECs), paralleled by protein kinase Cε (PKCε) reduction. Moreover, luciferase reporter gene analysis shows that PKCε is the target gene of miR-34a. We also show that cotransfection of miR-34a and PKCε inversely coregulates BTB permeability and protein expression levels of tight junction–related proteins. Pretreatment of ψεRACK, a PKCε-specific activator, decreases BTB permeability in miR-34a–overexpressed GECs and up-regulates expression levels of tight junction proteins. In contrast, pretreatment of εV1-2, a specific PKCε inhibitor, gives opposite results. Collectively, our findings indicate that miR-34a regulates BTB function by targeting PKCε; after phosphorylation, PKCε is activated and contributes to regulation of the expression of tight junction–related proteins, ultimately altering BTB permeability.

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