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)

The proinflammatory chemokine interleukin-8 (IL-8) is undetectable in androgen-responsive prostate cancer cells (e.g., LNCaP and LAPC-4), but it is highly expressed in androgen-independent metastatic cells, such as PC-3. In this report, we show IL-8 functions in androgen independence, chemoresistance, tumor growth, and angiogenesis. We stably transfected LNCaP and LAPC-4 cells with IL-8 cDNA and selected IL-8-secreting (IL8-S) transfectants. The IL8-S transfectants that secreted IL-8 at levels similar to that secreted by PC-3 cells (100-170 ng/10(6) cells) were characterized. Continuous or transient exposure of LNCaP and LAPC-4 cells to IL-8 reduced their dependence on androgen for growth and decreased sensitivity (>3.5x) to an antiandrogen. IL-8-induced cell proliferation was mediated through CXCR1 and was independent of androgen receptor (AR). Quantitative PCR, immunoblotting, and transfection studies showed that IL8-S cells or IL-8-treated LAPC-4 cells exhibit a 2- to 3-fold reduction in PSA and AR levels, when compared with vector transfectants. IL8-S cells expressed 2- to 3-fold higher levels of phospho-EGFR, src, Akt, and nuclear factor kappaB (NF-kappaB) and showed increased survival when treated with docetaxel. This increase was blocked by NF-kappaB and src inhibitors, but not by an Akt inhibitor. IL8-S transfectants displayed a 3- to 5-fold increased motility, invasion, matrix metalloproteinase-9 and vascular endothelial growth factor production. LNCaP IL8-S cells grew rapidly as tumors, with increased microvessel density and abnormal tumor vasculature when compared with the tumors derived from their vector-transfected counterparts. Therefore, IL-8 is a molecular determinant of androgen-independent prostate cancer growth and progression.
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PMID:Interleukin-8 is a molecular determinant of androgen independence and progression in prostate cancer. 1763 96

Resveratrol, a natural polyphenolic phytochemical, has been reported to act as an antioxidant and provide anticancer activities. We hypothesized that resveratrol would exert a chemopreventive effect against prostate cancer via regulation of sex steroid receptor and growth factor signaling pathways. In the current study, Transgenic Adenocarcinoma Mouse Prostate males were fed resveratrol (625 mg resveratrol per kg AIN-76A diet) or phytoestrogen-free, control diet (AIN-76A) starting at 5 weeks of age. Mechanisms of action and histopathology studies were conducted at 12 and 28 weeks of age, respectively. Resveratrol in the diet significantly reduced the incidence of poorly differentiated prostatic adenocarcinoma by 7.7-fold. In the dorsolateral prostate, resveratrol significantly inhibited cell proliferation, increased androgen receptor, estrogen receptor-beta, and insulin-like growth factor-1 receptor, and significantly decreased insulin-like growth factor (IGF)-1 and phospho-extracellular regulating kinase 1 (phospho-ERK 1). In the ventral prostate, resveratrol significantly reduced cell proliferation and phospho-ERKs 1 and 2, but did not significantly alter insulin-like growth factor-1 receptor and IGF-1. Serum total testosterone, free testosterone, estradiol, dihydrotestosterone and sex hormone-binding globulin (SHBG) concentrations and Simian Virus-40 large T antigen expression in the prostate were not altered in resveratrol-treated mice. Total resveratrol concentration in the blood serum of 12-week-old mice treated for 3 weeks with 625 mg resveratrol per kg diet was 52 +/- 18 nM. The decrease in cell proliferation and the potent growth factor, IGF-1, the down-regulation of downstream effectors, phospho-ERKs 1 and 2 and the increase in the putative tumor suppressor, estrogen receptor-beta, provide a biochemical basis for resveratrol suppressing prostate cancer development.
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PMID:Resveratrol suppresses prostate cancer progression in transgenic mice. 1767 39

In the male, androgens promote growth and differentiation of sex reproductive organs through ligand activation of the androgen receptor (AR). Here, we show that androgens are not major actors of the cell cycle arrest associated with the differentiation process, and that the epidermal growth factor (EGF)-mediated signalling interferes with AR activities to regulate androgen response when epithelial cells are differentiated. Higher AR expression and enhanced androgen responsiveness correlate with reduction of phosphorylated ERK1/2 over differentiation. These modifications are associated with recruitment of cells in phase G(0)/G(1), up-regulation of p27(kip1), down-regulation of p21(Cip1) and p53 proteins, and accumulation of hypo-phosphorylated Rb. Exposure to EGF reduces AR expression levels and blocks androgen-dependent transcription in differentiated cells. It also restores p53 and p21(Cip1) levels, Rb hyper-phosphorylation, ERK1/2 activation and promotes cell cycle re-entry as p27(kip1) protein levels are decreased. Treatment with a MEK inhibitor reverses the EGF-mediated AR down-regulation in differentiated cells, thus suggesting the existence of an inverse correlation between EGF and androgen signalling in non-tumoural epithelia. Interestingly, when androgen signalling is set in differentiated cells, dihydrotestosterone exerts an inhibitory effect on ERK activity but paradoxically does not modify EGFR (ErbB1) phosphorylation, indicating that androgens are able to disrupt the EGFR-ERK cascade. Overall, our data demonstrate the existence of a balance between AR and mitogen-activated protein kinase activities that favours either the maintenance of differentiated conditions or the enhancement of cell proliferation capacities.
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PMID:Crosstalk between androgen receptor and epidermal growth factor receptor-signalling pathways: a molecular switch for epithelial cell differentiation. 1769 13

The expression of the WWOX tumor suppressor gene is lost or reduced in a large fraction of various cancers, including prostate cancer. We previously reported that Wwox overexpression induced apoptosis and suppressed prostate cancer growth in vitro and in vivo. In this study, pathways through which Wwox contributes to control of prostate cancer cell growth have been investigated. We found that Wwox interacts with Ap2gamma and prevents it from entering the nucleus to bind the ERBB2 promoter region to activate transcription of ERBB2, a mediator of androgen receptor activity and prostate cancer cell growth at limiting androgen concentration. Ectopic expression of Wwox reduced ErbB2 protein expression in vitro and expression of Wwox protein inversely correlated with expression of ErbB2 protein in prostate cancer tissues. Furthermore, Wwox suppressed Ap2gamma/ErbB2-induced prostate cancer cell growth and suppressed prostate-specific antigen secretion through interaction with Ap2gamma and down-modulation of ErbB2, an effect that required functional androgen receptor.
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PMID:Wwox suppresses prostate cancer cell growth through modulation of ErbB2-mediated androgen receptor signaling. 1770 39

Enhanced mesenchymal expression of FGF10 led to the formation of multifocal PIN or prostate cancer. Inhibition of epithelial FGFR1 signaling using DN FGFR1 led to reversal of the cancer phenotype. A subset of the FGF10-induced carcinoma was serially transplantable. Paracrine FGF10 led to an increase in epithelial androgen receptor and synergized with cell-autonomous activated AKT. Our observations indicate that stromal FGF10 expression may facilitate the multifocal histology observed in prostate adenocarcinoma and suggest the FGF10/FGFR1 axis as a potential therapeutic target in treating hormone-sensitive or refractory prostate cancer. We also show that transient exposure to a paracrine growth factor may be sufficient for the initiation of oncogenic transformation.
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PMID:Enhanced paracrine FGF10 expression promotes formation of multifocal prostate adenocarcinoma and an increase in epithelial androgen receptor. 1806 33

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.
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PMID:Ligand-independent activation of androgen receptors by Rho GTPase signaling in prostate cancer. 1807 21

Juvenile nasopharyngeal angiofibroma (JNA) is a rare, invasive, and locally destructive tumor of the nasopharynx. The Wnt pathway, angiogenetic and hormonal factors are involved in the pathophysiology of JNA; it can result in an extracolonic manifestation of familial adenomatous polyposis (FAP) or in a sporadic tumor. All patients who underwent resection of JNA between 1991 and 2006 at the University of Modena and Reggio Emilia were studied to identify immunohistochemical markers of associated FAP syndrome. Paraffin-embedded JNA samples were analyzed immunohistochemically for the expression of adenomatous polyposis coli (APC), beta-catenin, E-cadherin, androgen receptor, and vascular endothelial growth factors receptor (VEGFR2). In one out of the 4 (25%) young patients affected by JNA the diagnosis of FAP syndrome linked to APC mutation was made. All of the sporadic and familial JNA tumors showed nuclear staining of beta-catenin, whereas altered APC expression was seen only in FAP-associated JNA. All cases were stained with VEGFR2. A combined clinical, immunohistochemical, and biomolecular screening may be useful for the identification of FAP among patients with a diagnosis of JNA. The Wnt pathway can be involved in the JNA pathogenesis either by somatic mutations of beta-catenin or by germline APC mutations. As the VEGFR has an important impact on the pathogenesis of JNA, we suggest that a targeted therapy with monoclonal antibodies against VEGFR might lead to a specific chemoprevention and treatment of these tumors and their recurrences.
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PMID:Wnt pathway, angiogenetic and hormonal markers in sporadic and familial adenomatous polyposis-associated juvenile nasopharyngeal angiofibromas (JNA). 1822 24

In this study, we explore the therapeutic potential of lapatinib a selective inhibitor of both the EGFR and HER2 tyrosine kinases for the treatment of endometrial cancer. The effect of lapatinib on tumour cell growth and receptor activation was studied in a panel of human endometrial cancer cell lines. Candidate molecular markers predicting sensitivity were assessed by baseline gene expression profiling, ELISA, and western blot analyses. Multiple drug effect/combination index (CI) isobologram analysis was used to study the interactions between chemotherapeutic drugs and lapatinib. Concentration-dependent anti-proliferative effects of lapatinib were seen in all endometrial cancer cell lines tested, but varied significantly between individual cell lines (IC(50) range: 0.052-10.9 micromol). HER2 overexpression or increased expression of EGFR was significantly associated with in vitro sensitivity (P=0.024 or 0.011, respectively). Lapatinib exerts growth inhibition in a PTEN-independent manner. Sensitive cell lines also exhibited increased expression of EGFR ligands or HER3. In contrast, lapatinib-resistant cell lines exhibited high androgen receptor (AR) levels or epithelial-to-mesenchymal transition (post-EMT) features. In endometrial cancer cells, at a wide range of clinically achievable drug concentrations, additive and synergistic interactions were observed for lapatinib plus carboplatin, paclitaxel, docetaxel, and doxorubicin. These observations provide a clear biologic rational to test lapatinib as a single agent or in combination with chemotherapy in endometrial cancer with HER2 overexpression. Expression of EGFR, its ligands, HER3, AR, and post-EMT markers warrant further evaluation to help define patients with HER2-nonoverexpressing endometrial cancer most likely to benefit from lapatinib.
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PMID:Activity of lapatinib a novel HER2 and EGFR dual kinase inhibitor in human endometrial cancer cells. 1833 72

Androgens and the androgen receptor (AR) are involved both in early tumorigenesis of prostate cancer (PCa) and in androgen-refractory disease. The role of AR signalling has also been highlighted by the fusion gene TMPRSS2:ERG recently identified in the majority of PCa. Several data indicate that re-expression of AR in PCa cell lines confers a less aggressive phenotype. We observed that re-expression of AR in the AR-negative cells PC3 decreases anchorage-independent growth and Matrigel invasiveness of PC3-AR cells where plasma membrane interaction between AR and EGFR led to an interference with downstream signalling and internalization of activated EGFR. Our data evidenced a shift of EGFR internalization pathway from the clathrin-coated pit one mediating signalling and recycling of EGFR to the lipid raft-mediated one mainly involved in lysosomal degradation of EGFR. These effects involved an altered recruitment to EGFR of the adaptor proteins Grb2 and c-Cbl followed by a reduced ubiquitination of EGFR. Our preliminary results suggest that in PC3-AR cells a pool of classical AR is located within cholesterol-rich membrane microdomains (namely as lipid rafts) and a population of EGFR is within cholesterol-rich membrane microdomains too. However, AR and EGFR membrane interaction that is increased by rapid androgen signalling is not within cholesterol-rich membrane microdomains. Our data enlighten that the crosstalk between genotropic and non-genotropic AR signalling interferes with signalling of EGFR in response to ligand leading to a lower invasive phenotype of AR-positive PCa cells.
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PMID:Prostate cancer: a model of integration of genomic and non-genomic effects of the androgen receptor in cell lines model. 1835 9

BRCA1 is a tumor suppressor gene which, when mutated, is associated with the development of hereditary breast cancers. In sporadic tumors, although inherent gene mutations are rare, loss of BRCA1, resulting from reduced expression or incorrect subcellular localization, is postulated to be important. The purpose of the current study was to examine the expression and localization of BRCA1 protein and to assess its prognostic value, in a well-characterized series of unselected breast carcinomas. We have examined BRCA1 in a series of invasive breast carcinoma (1940 cases) using tissue microarray and immunohistochemistry, to evaluate its expression pattern and to correlate this with clinicopathologic variables and patient outcome. In breast cancer, complete loss of nuclear expression was observed in 223 cases (15%) and cytoplasmic expression was found in 541 breast cancers (36.6%). Absent or reduced nuclear BRCA1 expression was observed more frequently in ductal carcinoma of no special type and medullary-like carcinoma and less frequently in lobular and tubular mixed carcinomas. It was also associated with high-grade, advanced lymph node stage, larger size, vascular invasion, negative estrogen receptor, progesterone receptor and androgen receptor expression, and positive p53 and P-cadherin expression, and with the basal-like class of breast cancer. Altered BRCA1 was associated with shorter disease-free interval. Cytoplasmic expression was also associated with development of recurrence and positive EGFR and HER2 expression. It showed an inverse association with survival particularly in low-grade, small-size, and estrogen receptor-positive subgroups. In the grade 1 subgroup, multivariate analysis with adjustment for other prognostic factors showed that cytoplasmic expression of BRCA1 was an independent predictor of disease-free interval. BRCA1 alteration may play a significant role in the development and progression of breast cancer. Immunohistochemical assessment of BRCA1 expression could provide additional clinically relevant information in routine classification of breast cancer.
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PMID:Expression of BRCA1 protein in breast cancer and its prognostic significance. 1840 Feb 53


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