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)

Overexpression and enhanced activation of the epidermal growth factor (EGF) receptor are frequent events in human cancers that correlate with poor prognosis. Anti-phosphotyrosine and anti-EGFr affinity chromatography, isotope-coded muLC-MS/MS, and immunoblot methods were combined to describe and measure signaling networks associated with EGF receptor activation and pharmacological inhibition. The squamous carcinoma cell line HN5, which overexpresses EGF receptor and displays sustained receptor kinase activation, was used as a model system, where pharmacological inhibition of EGF receptor kinase by erlotinib markedly reduced auto and substrate phosphorylation, Src family phosphorylation at EGFR Y845, while increasing total EGF receptor protein. Diverse sets of known and poorly described functional protein classes were unequivocally identified by affinity selection, comprising either proteins tyrosine phosphorylated or complexed therewith, predominantly through EGF receptor and Src family kinases, principally 1) immediate EGF receptor signaling complexes (18%); 2) complexes involved in adhesion and cell-cell contacts (34%); and 3) receptor internalization and degradation signals. Novel and known phosphorylation sites could be located despite the complexity of the peptide mixtures. In addition to interactions with multiple signaling adaptors Grb2, SHC, SCK, and NSP2, EGF receptors in HN5 cells were shown to form direct or indirect physical interactions with additional kinases including ACK1, focal adhesion kinase (FAK), Pyk2, Yes, EphA2, and EphB4. Pharmacological inhibition of EGF receptor kinase activity by erlotinib resulted in reduced phosphorylation of downstream signaling, for example through Cbl/Cbl-B, phospholipase Cgamma (PLCgamma), Erk1/2, PI-3 kinase, and STAT3/5. Focal adhesion proteins, FAK, Pyk2, paxillin, ARF/GIT1, and plakophillin were down-regulated by transient EGF stimulation suggesting a complex balance between growth factor induced kinase and phosphatase activities in the control of cell adhesion complexes. The functional interactions between IGF-1 receptor, lysophosphatidic acid (LPA) signaling, and EGF receptor were observed, both direct and/or indirectly on phospho-Akt, phospho-Erk1/2, and phospho-ribosomal S6.
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PMID:Phosphotyrosine signaling networks in epidermal growth factor receptor overexpressing squamous carcinoma cells. 1565 67

Transforming growth factor-alpha (TGF-alpha) is abnormally expressed in autosomal recessive polycystic kidney disease (ARPKD). Tumor necrosis factor-alpha converting enzyme (TACE), a metalloproteinase, mediates TGF-alpha processing. In this study, we sought to determine whether TGF-alpha was an absolute requirement for renal cystogenesis and whether its absence would modulate disease severity or related growth factors/receptors expression. Bpk heterozygotes were bred with TGF-alpha null mice to produce cystic and noncystic offspring with or without TGF-alpha. Assessments included kidney weight (KW), body weight (BW), blood urea nitrogen (BUN), and kidney and liver immunohistology. Western analysis assessed kidney expression of amphiregulin (AR), epidermal growth factor (EGF), heparin-binding EGF (HB-EGF), and their receptors, EGFR and ErbB4. A PCR-based methodology for genotyping bpk mice was also developed. No significant differences in KW, BW, KW/BW%, or BUN were seen in cystic mice with versus without TGF-alpha. Cystic kidney disease and liver disease histology were similar. AR, EGF, HB-EGF, EGFR, and ErbB4 were abnormally expressed to an equal degree in kidneys of mice with versus without TGF-alpha. Although previous data suggest a critical role of TGF-alpha in murine PKD, these data show that TGF-alpha is not required for renal cyst formation or kidney or liver disease progression. We speculate that the therapeutic effect of WTACE2 could have been due to effects on several TACE targets, including TGF-alpha, AR, and ErbB4, as well as metalloproteinases other than TACE.
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PMID:Transforming growth factor alpha (TGF-alpha) and other targets of tumor necrosis factor-alpha converting enzyme (TACE) in murine polycystic kidney disease. 1577 23

Androgens have been implicated in mediating disease escalation in autosomal dominant polycystic kidney disease (ADPKD). Dihydrotestosterone (DHT), an agonist, and flutamide (FLT), an antagonist, were administered to Han:SPRD rats with ADPKD, and the role of androgen receptor (AR) abundance and activation on the enlargement and function of cystic kidneys was evaluated. Renal AR abundance determined by immunoblots in 8- to 10-wk-old Cy/+ male rats was naturally increased four-fold above that of littermate +/+ controls. In male Cy/+, castration decreased AR abundance below control +/+ by -89.4%, and AR expression within cyst mural epithelial cells was strikingly decreased. Castration of Cy/+ male rats also reduced the usual increases in kidney weight by -49.7%, kidney cyst area by -34.0%, and serum urea nitrogen by -72.8%; these indices were restored to precastration levels by DHT. In Cy/+ male rats, FLT administration reduced the increase in kidney weight by -27.6% and serum urea nitrogen by -53.7% and decreased the increment in AR expression by -84.2% in comparison with untreated +/+ controls. There was no effect of FLT in female rats. Immunoblot expression of phospho-extracellular signal-regulated kinase 1/2 (P-ERK) and B-Raf, key intermediates in the mitogen-activated protein kinase pathway that are abnormally elevated in Cy/+, was unaffected by castration and/or administration of DHT or FLT. AR was not expressed in renal epithelial cell nuclei of androgen-deficient rats but was displayed in most tubule and mural cyst cell nuclei of androgen-replete rats. In androgen-deficient Cy/+, 80.6% of renal epithelial cells that had entered the cell cycle (proliferating cell nuclear antigen positive) also expressed P-ERK. In androgen-replete rats, proliferating cell nuclear antigen-positive cells co-expressed AR (12.7%), P-ERK (36.4%), and P-ERK + AR (45.0%); 5.9% were probably stimulated by other mitogenic mechanisms. It is concluded that androgens potentiate renal cell proliferation and cyst enlargement through ERK1/2-dependent and ERK1/2-independent signaling mechanisms in Han:SPRD. It is suggested that the basal rate of cell proliferation is determined by ERK1/2 signaling to a major extent and that androgens have additive effects.
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PMID:Androgen receptor pathway in rats with autosomal dominant polycystic kidney disease. 1588 69

Two metachronous anaplastic oligoastrocytomas with different cerebral locations were analyzed in a 51-year-old patient with an extended recurrence-free interval of 6 years and an a long survival of 9 years. Remarkably, the patient had not undergone adjuvant chemotherapy. Different cytogenetic and molecular techniques were performed including comparative genomic hybridization (CGH), fluorescence in situ hybridization (FISH), allelic loss analysis, sequencing of p53, p16(INK4a)/CDKN2A and p14(ARF), EGFRamplification studies, investigation of the DNA mismatch repair system as well as tumor clonality. Using CGH and FISH a profile of low accumulation of cytogenetic aberrations was found in the second tumor, with no significant increase in the percentage of hyperdiploid nuclei. Microsatellite analysis showed a common pattern of allelic losses at 1p36, 19q13 and 9p21. Both specimens were also similar in that they retained heterozygosity at 10q23-q24 and 13q14 and that they harbor neither EGFR amplification nor mutations of p53, p16(INK4a)/CDKN2A or p14(ARF). The only further alteration in the second tumor was an allelic loss at p53. The X-chromosome inactivation (HUMARA) analysis revealed a polyclonal pattern in both samples. Our data strongly suggest that the second anaplastic oligoastrocytoma developed as a distant relapse of the first tumor. Whether the paucity of accumulation of the observed genetic alterations might be associated with the unusually extended relapse-free time of the patient remains to be elucidated.
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PMID:Comparative genetic analysis of metachronous anaplastic oligoastrocytomas with extended recurrence-free interval. 1592 87

Anaplastic astrocytoma (AA, WHO grade III) is, second to Glioblastoma, the most common and most malignant type of adult CNS tumour. Since survival for patients with AA varies markedly and there are no known useful prognostic or therapy response indicators, the primary purpose of this study was to examine whether knowledge of the known genetic abnormalities found in AA had any clinical value. The survival data on 37 carefully sampled AA was correlated with the results of a detailed analysis of the status of nine genes known to be involved in the development of astrocytic tumours. These included three genes coding for proteins in the p53 pathway (TP53, p14(ARF)and MDM2), four in the Rb1 pathway (CDKN2A, CDKN2B, RB1 and CDK4) and PTEN and EGFR. We found that loss of both wild-type copies of any of the three tumour suppressor genes CDKN2A, CDKN2B and RB1 or gene amplification of CDK4, disrupting the Rb1 pathway, were associated with shorter survival (P=0.009). This association was consistent in multivariate analysis, including adjustment for age (P=0.013). The findings suggest that analysis of the genes coding for Rb1 pathway components provides additional prognostic information in AA patients receiving conventional therapy.
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PMID:Mutations in Rb1 pathway-related genes are associated with poor prognosis in anaplastic astrocytomas. 1597 Sep 25

L-arginine is metabolized to nitric oxide (NO) by NO synthase (NOS), or to urea and L-ornithine by arginase. L-ornithine contributes to vascular remodeling in pulmonary hypertension via metabolism to polyamines and proline. Previously we found that cytokines upregulate both NOS and arginase in pulmonary arterial endothelial cells. We hypothesized that cytokine-induced arginase I and II expression depend on epidermal growth factor (EGF) receptor (EGFR) activity. Bovine pulmonary arterial endothelial cells were treated with lipopolysaccharide and tumor necrosis factor-alpha (L/T). L/T treatment resulted in a substantial increase in urea production, and this increase in urea production was potently inhibited by both genistein and AG1478, inhibitors of EGFR. Levels of arginase I protein and arginase II mRNA were increased in response to L/T treatment, and genistein prevented the L/T-induced elevations in both arginase I protein and arginase II mRNA levels. L/T treatment increased production of nitrites and inducible NOS mRNA accumulation, and genistein and AG1478 had little effect on these changes. EGF (50 ng/ml) treatment resulted in enhanced urea production. Finally, a 170-kD protein was phosphorylated upon treatment with either EGF or L/T. Our results indicate that arginase induction by L/T depends in part on EGFR activity. We speculate that EGFR inhibitors may attenuate vascular remodeling without affecting NO release, and thus may represent novel therapeutic modalities for pulmonary hypertensive disorders.
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PMID:Cytokine-induced endothelial arginase expression is dependent on epidermal growth factor receptor. 1599 32

7-Substituted 3-aryl-1,6-naphthyridine-2,7-diamines and related 2-ureas are inhibitors of fibroblast growth factor receptor-1 (FGFR-1) and vascular endothelial growth factor receptor-2 (VEGFR-2). 3-(3,5-Dimethoxyphenyl) and 3-phenyl analogues were prepared from 7-acetamido-2-tert-butylureas by alkylation with benzyl omega-iodoalkyl ethers, debenzylation, and amination, followed by selective cleavage of the 7-N-acetamide. 3-(2,6-Dichlorophenyl) analogues were prepared from the 7-fluoro-2-amine by displacement with substituted alkylamines, followed by selective acylation of the resulting substituted naphthyridine-2,7-diamines with alkyl isocyanates. The 3-(3,5-dimethoxyphenyl) derivatives were low nanomolar inhibitors of both FGFR and VEGFR and were highly selective (>100-fold) over PDGFR and c-Src. Variations in the base strength or spatial position of the 7-side chain base had only small effects on the potency (<5-fold) or selectivity (<20-fold). The 3-(2,6-dichlorophenyl)-2-urea derivatives were slightly less active against VEGFR and less selective, being more effective against PDGFR (ca. 10-fold) and c-Src (ca. 500-fold). The 3-(3,5-dimethoxyphenyl)-1,6-naphthyridines were generally more potent than the corresponding pyrido[2,3-d]pyrimidines against both VEGFR and FGFR (2- to 20-fold), with only slightly increased PDGFR and c-Src activity. The 3-(3,5-dimethoxyphenyl)-1,6-naphthyridine 2-ureas were also low nanomolar inhibitors of the growth of human umbilical vein endothelial cells (HUVECs) stimulated by serum, FGF, or VEGF, at concentrations that did not affect the growth of representative tumor cell lines, and were more (3- to 65-fold) potent than the corresponding pyrido[2,3-d]pyrimidines.
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PMID:Synthesis and structure-activity relationships of soluble 7-substituted 3-(3,5-dimethoxyphenyl)-1,6-naphthyridin-2-amines and related ureas as dual inhibitors of the fibroblast growth factor receptor-1 and vascular endothelial growth factor receptor-2 tyrosine kinases. 1600

Exposure of primary cells to mitogenic stimuli or oncogenes often causes them to undergo premature senescence. This is most likely a protective function that prevents uncontrolled proliferation. Pak4 is a target for the Rho GTPase Cdc42. Pak4 is overexpressed in human tumor cell lines, and it is the only member of the Pak family that is highly transforming in immortalized fibroblasts. Here we show that in primary fibroblasts, activated Pak4 inhibits cell proliferation and promotes premature senescence. Furthermore, Pak4 expression levels are upregulated in response to stimuli that promote senescence. Pak4-induced arrest appears to be mediated by a pathway that requires the ERK mitogen-activated protein kinase, as well as the cell cycle inhibitors p16(INK4) and p19(ARF). These new results describing a role for Pak4 in senescence are important for understanding why this protein is associated with cancer and how it promotes transformation in immortalized cells.
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PMID:Pak4 induces premature senescence via a pathway requiring p16INK4/p19ARF and mitogen-activated protein kinase signaling. 1622 3

The objective of the present study was to evaluate the recently proposed aerobic machine preservation with the noncolloidal HTK solution by comparison with the colloidal Belzer machine perfusion solution (MPS) after procurement of marginal kidneys from non-heart-beating donors. Kidneys were harvested 40 minutes after cardiac arrest in German Landrace pigs and subjected to 18 hours of oxygenated hypothermic machine perfusion with either Belzer MPS or modified HTK via the renal artery (Psys < 40 mm Hg). During machine perfusion transrenal flow was approximatively twofold higher and calculated oxygen uptake was increased by 30% using the colloidal Belzer MPS, but overall enzyme release was comparable in both groups. After heterotopic transpantation with bilateral nephrectomy of the recipient, there were no differences with respect to initial tissue perfusion in vivo (evaluated by laser Doppler flowmetry) as well as urine production and median serum levels of urea or creatinine over 1 week of follow-up between grafts perfused with HTK or Belzer MPS. In conclusion, provision of oxygen during storage is possible by low-flow perfusion with HTK as with Belzer MPS.
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PMID:Oxygenated machine perfusion preservation of predamaged kidneys with HTK and Belzer machine perfusion solution: an experimental study in pigs. 1629 70

Isoflurane has a pharmacological preconditioning effect against ischemia in the heart and brain, but whether this also occurs in the kidney is unclear. In this study, we investigated pharmacological preconditioning by isoflurane in the rat kidney. In the isoflurane preconditioning group (1.5% isoflurane for 20 min before renal ischemia) serum creatinine (1.2 +/- 0.7 and 1.1 +/- 0.2 mg/dL) and blood urea nitrogen (99 +/- 29 and 187 +/- 31 mg/dL) were significantly smaller at 24 and 48 h after reperfusion than in the nonpreconditioning group (creatinine; 2.4 +/- 1.2 and 2.9 +/- 0.9 mg/dL, urea; 62 +/- 19 and 79 +/- 20 mg/dL). We also investigated the intracellular signal transduction involved in isoflurane preconditioning in the kidney. The activities of the stress protein kinases, JNK and ERK but not p38, were significantly less in the kidneys of the preconditioning group than in those of the nonpreconditioning group (P < 0.05). We conclude that isoflurane has a preconditioning effect against renal ischemia/reperfusion injury when administered before ischemia. Inhibition of the protein kinases, JNK and ERK, might be involved in the mechanisms of isoflurane preconditioning.
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PMID:Isoflurane protects renal function against ischemia and reperfusion through inhibition of protein kinases, JNK and ERK. 1700 Aug 48


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