Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Alterations in the signaling pathways of bone morphogenetic proteins (BMPs) and activation of the ERK/MAP kinase (MAPK) pathway by growth factors have been implicated in the development and progression of prostate cancer. Smad1 acts as a substrate for MAPKs and also performs a central role in transmitting signals from BMPs. We found that BMPs/Smad1 signaling inhibits the growth of androgen-sensitive prostate cancer cells. Upon the incorporation of ERK/MAPK signals at its linker region, Smad1 physically interacts with androgen-activated androgen receptor (AR) and suppresses its functions. BMPs induce the function of Smad1 as an AR transcriptional corepressor. We demonstrated in vivo that Smad1 signaling is low in androgen-regulated growth of prostate cancer, is activated after castration, and also is decreased in hormone-independent tumors. The activation status of ERK/MAPK parallels Smad1 in the progression of prostate cancer; thus, our findings indicate a molecular basis for the integration of signals of MAPK and Smad1 in the progression and androgen regulation of prostate cancer.
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PMID:Control of prostate cell growth: BMP antagonizes androgen mitogenic activity with incorporation of MAPK signals in Smad1. 1718 65

Ginsenosides have been shown to stimulate nitric oxide (NO) production in aortic endothelial cells. However, the signaling pathways involved have not been well studied in human aortic endothelial cells. The present study was designed to examine whether purified ginsenoside Rb1, a major active component of ginseng could actually induce NO production and to clarify the signaling pathway in human aortic endothelial cells. NO production was rapidly increased by Rb1. The rapid increase in NO production was abrogated by treatment with nitric oxide synthetase inhibitor, L-NAME. Rb1 stimulated rapid phosphorylation of Akt (Ser473), ERK1/2 (Thr202/Thr204) and eNOS (Ser1177). Rapid phosphorylation of eNOS (Ser1177) was prevented by SH-5, an Akt inhibitor or wortmannin, PI3-kinase inhibitor and partially attenuated by PD98059, an upstream inhibitor for ERK1/2. Interestingly, NO production and eNOS phosphorylation at Ser1177 by Rb1 were abolished by androgen receptor antagonist, nilutamide. The results suggest that PI3kinase/Akt and MEK/ERK pathways and androgen receptor are involved in the regulation of acute eNOS activation by Rb1 in human aortic endothelial cells.
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PMID:Signaling pathway of nitric oxide production induced by ginsenoside Rb1 in human aortic endothelial cells: a possible involvement of androgen receptor. 1719 33

A 44-year-old man was referred for a right chest nodule of 3 months duration. A 'benign' nodule had been excised from this location 8 years prior. On examination, palpable nodes were noted in the right axilla. Radiographic studies were significant only for right axillary lymphadenopathy. Histologically, a nodular dermal proliferation composed of poorly differentiated epithelioid cells in nests and focally forming ducts with pseudopapillary architecture comprised the primary tumor. Features of a clear cell hidradenoma were noted focally. Immunohistochemical (IHC) analysis revealed reactivity for HMW cytokeratins, CK5 and CK7, p53, p63, CEA (focal), androgen receptor, EGFR, estrogen receptor (ER), MUC5AC, and strong/diffuse membranous staining for Her-2/neu. Negative stains included villin, TTF-1, CDX2, S-100 protein, vimentin, gross cystic disease fluid protein 15 (GCDFP-15), mammoglobulin, and MUC2. A wide local excision and axillary node dissection was performed. Metastatic tumor involved nine of 28 nodes. Interphase fluorescence in situ hybridization (FISH) demonstrated chromosomal amplification of the Her-2/neu locus within the tumor and a nodal metastasis. The patient has completed adjuvant and radiotherapy, including trastuzumab, and is asymptomatic. We believe this to be the first demonstration of Her-2/neu amplification in a malignant skin adnexal tumor. In analogy to breast carcinoma, these findings suggest the applicability of trastuzumab for patients with metastatic adnexal carcinomas demonstrating Her-2/neu amplification.
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PMID:Metastatic hidradenocarcinoma with demonstration of Her-2/neu gene amplification by fluorescence in situ hybridization: potential treatment implications. 1721 55

A new pathway of testosterone (T) action in Sertoli cells was recently identified that may be required to support spermatozoa production (spermatogenesis) and fertility. Specifically, T acts via the androgen receptor (AR) to rapidly activate the MAPK cascade and the cAMP response element-binding protein (CREB) transcription factor in Sertoli cells. In further characterizing the signaling pathway that transduces T actions, we now find that a population of AR is localized to the plasma membrane and that AR associates with Src kinase after T stimulation. In addition, we demonstrate that Src kinase is activated by T and that Src kinase activity is required for stimulation of the ERK MAPK and CREB. Furthermore, we determine that activation of the epidermal growth factor receptor downstream of Src contributes to the activation of the MAPK cascade and CREB. The elucidation of this nonclassical pathway of T action in the testis may provide new targets for the control of male fertility.
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PMID:Testosterone activates mitogen-activated protein kinase via Src kinase and the epidermal growth factor receptor in sertoli cells. 1727 94

In the central nervous system, androgens can exert either protective or damage-promoting effects. For example, testosterone protects neurons against beta-amyloid toxicity, whereas in other studies, testosterone exacerbated stroke-induced lesion size. The mechanism underlying this duality of androgens is still unclear. Recently, our laboratory reported that androgens elicit opposite effects on the ERK/MAPK and Akt signaling pathways, depending on whether a membrane androgen receptor (AR) or intracellular AR was activated. By extension, we hypothesized that androgens may affect cell viability differently depending on which receptor is activated. Here, we found that dihydrotestosterone (DHT) protected primary cortical astrocytes from the metabolic and oxidative insult associated with iodoacetic acid-induced toxicity, whereas DHT-BSA, a cell impermeable analog of DHT that preferentially targets the membrane AR, suppressed Akt signaling, increased caspase 3/7 activity, and enhanced iodoacetic acid-induced cell death. Interestingly, DHT-BSA also blocked the protective effects of DHT and estradiol. Collectively, these data support the existence of two, potentially competing, pathways for androgens in a given cell or tissue that may provide insight into the controversy of whether androgen therapy is beneficial or detrimental.
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PMID:Activation of a membrane-associated androgen receptor promotes cell death in primary cortical astrocytes. 1730 58

Activation of the androgen receptor (AR) may play a role in androgen-independent progression of prostate cancer. Multiple mechanisms of AR activation, including stimulation by tyrosine kinases, have been postulated. We and others have recently shown involvement of activated Cdc42-associated tyrosine kinase Ack1 in advanced human prostate cancer. Here we provide the molecular basis for interplay between Ack1 and AR in prostate cancer cells. Activated Ack1 promoted androgen-independent growth of LNCaP and LAPC-4 prostate xenograft tumors, AR recruitment to the androgen-responsive enhancer, and androgen-inducible gene expression in the absence of androgen. Heregulin-stimulated HER2 activation induced Ack1 activation and AR tyrosine phosphorylation. Ack1 knockdown inhibited heregulin-dependent AR tyrosine phosphorylation, AR reporter activity, androgen-stimulated gene expression, and AR recruitment. Ack1 was recruited to the androgen-responsive enhancers after androgen and heregulin stimulation. In 8 of 18 primary androgen-independent prostate tumor samples, tyrosine-phosphorylated AR protein was detected and correlated with the detection of tyrosine-phosphorylated Ack1. Neither was elevated in androgen-dependent tumors or benign prostate samples. Activated Ack1 phosphorylated AR protein at Tyr-267 and Tyr-363, both located within the transactivation domain. Mutation of Tyr-267 completely abrogated and mutation of Tyr-363 reduced Ack1-induced AR reporter activation and recruitment of AR to the androgen-responsive enhancer. Expression of AR point mutants inhibited Ack1-driven xenograft tumor growth. Thus, Ack1 activated by surface signals or oncogenic mechanisms may directly enhance AR transcriptional function and promote androgen-independent progression of prostate cancer. Targeting the Ack1 kinase may be a potential therapeutic strategy in prostate cancer.
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PMID:Activated Cdc42-associated kinase Ack1 promotes prostate cancer progression via androgen receptor tyrosine phosphorylation. 1749 60

Aberrant regulation in the adhesive ability of cancer cells is closely associated with their metastatic activity. In this study, we examine the role of ErbB-2 in regulating the adhesive ability of androgen receptor (AR)-positive human prostate cancer (PCa) cells, the major cell population of PCa. Utilizing different LNCaP and MDA PCa2b cells as model systems, we found that ErbB-2 activity was correlated with PYK2 activity and adhesive ability in those cells. Increased ErbB-2 expression or activity in LNCaP C-33 cells enhanced PYK2 activation and cell adhesion, while the high PYK2 activity and the rapid adhesion of LNCaP C-81 cells were decreased by diminishing ErbB-2 expression or activity. Knockdown studies revealed the predominant role of ErbB-2 in regulating LNCaP C-81 cell adhesion. Coimmunoprecipitation showed that C-81 cells had increased interaction between ErbB-2 and PYK2. Elevated ErbB-2 activity in LNCaP cells correlated with increased ERK/MAPK activity and enhanced adhesive ability, which were abolished by the expression of K457A-PYK2 mutant or the treatment of PD98059, a MEK inhibitor. In summary, our data suggested that ErbB-2, via PYK2-ERK/MAPK, upregulates the adhesive ability of AR-positive human PCa cells.
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PMID:ErbB-2 via PYK2 upregulates the adhesive ability of androgen receptor-positive human prostate cancer cells. 1756 46

The basal transcriptional activity of nuclear receptors (NRs) is regulated by interactions with additional comodulator proteins (coactivator/corepressor). Here, we describe a new androgen receptor (AR)-associated coactivator, PRMT2, which belongs to the arginine methyltransferase protein family. To search for AR-interacting proteins a fragment of the AR was used in a library screen exploiting the yeast two-hybrid technique and identifying the C-terminal region of PRMT2. We demonstrated that PRMT2 acts as a strong coactivator of the AR, had modest or none influence on transcriptional activation mediated by other NRs. Interestingly, PRMT2 interaction with the estrogen receptor (ER) was strongly dependent on the cellular background, thus, suggesting the involvement of additional, differentially expressed coregulators. We also demonstrated synergistic interaction of PRMT2 with other known nuclear receptor coactivators, such as GRIP1/TIF-2. Potentiation of AR-mediated transactivation by PRMT2 alone and in synergism with GRIP1 was prevented by a competitive inhibitor of methyltransferase activity. The PRMT2 expression profile overlaps with the distribution of AR, with strongest PRMT2 abundance in androgen target tissues. Immunofluorescence experiments showed that the intracellular localization of PRMT2 depends on the presence of the cognate receptor ligand. Under androgen-free conditions, both AR and PRMT2 are confined to the cytoplasm, whereas in the presence of androgens both proteins colocalize and translocate into the nucleus. Treatment with the AR antagonist hydroxyflutamide results in nuclear translocation of the AR, but not the coactivator PRMT2. Thus, it appears that the ligand-dependent AR conformation is essential for the recruitment and nuclear translocation of PMRT2 which acts as AR-coactivator, presumably by arginine methylation.
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PMID:PRMT2, a member of the protein arginine methyltransferase family, is a coactivator of the androgen receptor. 1758 66

PTEN mutations are among the most frequent genetic alterations found in human prostate cancers. Our previous works suggest that although precancerous lesions were found in Pten heterozygous mice, cancer progression and metastasis only happened when both alleles of Pten were deleted. To understand the molecular mechanisms underlying the role of PTEN in prostate cancer control, we generated two pairs of isogenic, androgen receptor (AR)-positive prostate epithelial lines from intact conditional Pten knock-out mice that are either heterozygous (PTEN-P2 and -P8) or homozygous (PTEN-CaP2 and PTEN-CaP8) for Pten deletion. Further characterization of these cells showed that loss of the second allele of Pten leads to increased anchorage-independent growth in vitro and tumorigenesis in vivo without obvious structural or numerical chromosome changes based on SKY karyotyping analysis. Despite no prior exposure to hormone ablation therapy, Pten null cells are tumorigenic in both male and female severe combined immunodeficiency mice. Furthermore, knocking down PTEN can convert the androgen-dependent Myc-CaP cell into androgen independence, suggesting that PTEN intrinsically controls androgen responsiveness, a critical step in the development of hormone refractory prostate cancer. Importantly, knocking down AR by shRNA in Pten null cells reverses androgen-independent growth in vitro and partially inhibited tumorigenesis in vivo, indicating that PTEN-controlled prostate tumorigenesis is AR dependent. These cell lines will serve as useful tools for understanding signaling pathways controlled by PTEN and elucidating the molecular mechanisms involved in hormone refractory prostate cancer formation.
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PMID:Murine cell lines derived from Pten null prostate cancer show the critical role of PTEN in hormone refractory prostate cancer development. 1761 63

Androgens play an important role in controlling the growth of the normal prostate gland and in the pathogenesis of benign prostate hyperplasia, and prostate cancer. Although testosterone is the main androgen secreted from the testes, dihydrotestosterone (DHT), a more potent androgen converted from testosterone by 5alpha-reductase isozymes, type I and II, is the major androgen in the prostate cells. The aim of this study is to investigate the cellular and molecular effects of dutasteride, a potent inhibitor of 5alpha-reductase type I and type II, in androgen-responsive (LNCaP) and androgen-unresponsive (DU145) human prostate cancer(PCa) cell lines. The expression pattern of 190 genes, selected on the basis of their proved or potential role in prostate cancerogenesis related to androgen signalling, were analysed using a low density home-made oligoarray (AndroChip 2). Our results show that dutasteride reduces cell viability and cell proliferation in both cell lines tested. AndroChip 2 gene signature identified in LNCaP a total of 11 genes differentially expressed (FC >or= +/-1.5). Eight of these genes, were overexpressed and three were underexpressed. Overexpressed genes included genes encoding for proteins involved in biosynthesis and metabolism of androgen (HSD17B1;HSD17B3;CYP11B2), androgen receptor and androgen receptor co-regulators (AR;CCND1), and signal transduction(ERBB2; V-CAM; SOS1) whereas, underexpressed genes (KLK3; KLK2; DHCR24) were androgen-regulated genes (ARGs). No differentially expressed genes were scored in DU145. Microarray data were confirmed by quantitative real-time PCR assay (QRT-PCR). These data offer a selective genomic signature for dutasteride treatment in prostate epithelial cells and provide important insights in prostate cancer pathophysiology.
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PMID:Effects of dutasteride on the expression of genes related to androgen metabolism and related pathway in human prostate cancer cell lines. 1763 12


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