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)

Gefitinib (Iressa() is an orally active, selective EGFR tyrosine kinase inhibitor that blocks signal transduction pathways. Skin toxicity has been reported to be the major toxicity observed in patients treated with the EGFR-targeted tyrosine kinase inhibitors, such as gefitinib and erlotinib. Although the mechanisms underlying the development of the skin toxicity remain to be precisely clarified, immunological mechanisms are considered to be involved. We examined the correlations between the plasma levels of several cytokines and the risk of development of adverse events, especially skin toxicity, induced by the administration of gefitinib as first-line monotherapy in non-small cell lung cancer (NSCLC) patients. Paired plasma samples were obtained from a total 28 patients of non-small cell lung cancer; the first before the initiation of gefitinib administration (250 mg/day) (24 patients) and the second 2 or 4 weeks after the initiation of treatment (23 patients). The plasma concentrations of 17 major cytokines were measured using a bead-based multiplex assay. The median concentrations of eight of these cytokines before the start of treatment ranged from 0.06 (IL-5) to 58.26 (MIP-1beta) (microg/ml). The concentrations of the remaining nine cytokines were under the detectable limit (<0.01 microg/ml) in more than 50% of the samples. Comparisons of the levels before and after treatment showed no significant differences for any of the cytokines measured. The MIP-1beta levels were significantly lower in the patients with skin toxicity (16/24) as compared with those in the patients not showing any skin toxicity (59.1+/-10.5 versus 119.0+/-36.8; p=0.042 by the two-sample t-test). The K-Nearest Neighbor Prediction (K=3) showed the classification rate to be 75% for the prediction sets containing MIP-1beta, IL-4 and IL-8. There were no significant associations between the levels of any of the cytokines measured and any other parameters, including the tumor response to the drug. In conclusion, the plasma MIP-1beta level may be a useful predictor of the development of skin toxicity in patients receiving gefitinib treatment.
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PMID:Plasma MIP-1beta levels and skin toxicity in Japanese non-small cell lung cancer patients treated with the EGFR-targeted tyrosine kinase inhibitor, gefitinib. 1615 43

Epidermal growth factor receptor (EGFR) is frequently amplified and/or mutated in a number of human tumours and abnormal signalling from this receptor is believed to contribute to the malignant phenotype seen in these tumours. Gefitinib is a small molecule inhibitor that specifically binds and inhibits the EGFR tyrosine kinase and has been shown to inhibit the growth, proliferation, survival and invasion of a range of tumour cells overexpressing EGFR. However, clinical response to gefitinib has failed to correlate with EGFR levels and activity, indicating that other molecular mechanisms such as downstream signalling and mutations could be of importance in predicting clinical response. We therefore investigated the effect of the specific EGFR inhibitor gefitinib on the phosphorylation level, signalling and growth of cells expressing the naturally occurring constitutively active EGFR variant EGFRvIII, a low nontransforming level of EGFR and a high transforming level of EGFR. Results show that levels of gefitinib sufficient to suppress EGFR phosphorylations, EGFR-mediated proliferation and EGFR-mediated anchorage-independent growth are not sufficient to inhibit these features in cells expressing EGFRvIII. Furthermore, the data indicate that long-term exposure of EGFRvIII-expressing cells to low concentrations of gefitinib (0.01-0.1 microM) result in increased phosphotyrosine load of the receptor, increased signalling to ERK and stimulation of proliferation and anchorage-independent growth, presumably by inducing EGFRvIII dimerisation. Higher concentrations of gefitinib (1-2 microM), on the other hand, significantly decreased EGFRvIII phosphotyrosine load, EGFRvIII-mediated proliferation and anchorage-independent growth. Further studies are needed to investigate the implications of these important findings in the clinical setting.
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PMID:Differential response to gefitinib of cells expressing normal EGFR and the mutant EGFRvIII. 1618 24

Modulation of ERBB and insulin-like growth factor 1 (IGF-1) receptor function is recognized as a potential mechanism to inhibit tumor growth. We and others have shown that inhibition of ERBB1 can enhance bile acid toxicity. Herein, we extend our analyses to examine the impact of insulin/IGF-1 receptor inhibition on primary hepatocyte survival when exposed to the secondary bile acid deoxycholic acid (DCA) and compare the impact inhibition of this receptor has on bile acid toxicity effects to that of ERBB1/MEK1/2 inhibition. The insulin/IGF-1 receptor inhibitor NVP-ADW742 at concentrations which inhibit both the insulin and IGF-1 receptors had a modest negative impact on hepatocyte viability, and strongly potentiated DCA-induced apoptotic cell death. Identical data were obtained expressing a dominant negative IGF-1 receptor in hepatocytes; a receptor which acts to inhibit both the IGF-1 receptor and the insulin receptor in trans. Inhibition of ERBB1 function using Iressa (gefitinib) or the tyrphostin AG1478 had more modest effects at enhancing DCA lethality than inhibition of the insulin/IGF-1 receptor function. In contrast, over-expression of a dominant negative ERBB1 protein had pleiotropic effects on multiple signaling pathways in an apparently non-specific manner. These findings suggest that novel therapeutic kinase inhibitors, targeted against growth factor receptors, have the potential to promote bile acid toxicity in hepatocyte when bile flow may be impaired.
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PMID:Inhibition of insulin/IGF-1 receptor signaling enhances bile acid toxicity in primary hepatocytes. 1620 85

An important recent advance in anticancer therapy was the development of molecular-targeting drugs, such as the epidermal growth-factor receptor (EGFR)-targeting drug ZD1839 (Iressa) and the HER2-trageting anti-HER2 monoclonal antibody trastuzumab (Herceptin). ZD1839 and trastuzumab are reported to improve the therapeutic efficacy of treatment for non-small-cell lung cancer (NSCLC) and breast cancer, respectively, although the effectiveness of either drug alone is not satisfactory. NSCLC cells often express both EGFR and HER2. We therefore investigated whether a combination of ZD1839 and trastuzumab had an additive or synergistic antitumor effect. In culture ZD1839 inhibited the growth of four NSCLC cell lines (A549, NCI-H23, NCI-H727, and NCI-H661) that expressed various levels of EGFR, HER2, HER3, and HER4. A significant cytotoxic effect was observed when ZD1839 was combined with trastuzumab in A549 cells. However, this combination had no apparent effect in NCI-H23 cells. Significant G(1)-phase arrest, increased p27 expression and decreased cyclin E or D1 levels were detected in A549 cells treated with ZD1839 and trastuzumab. No significant effects were detected in NCI-H23 cells examined. The combination treatment significantly inhibited the phosphorylation of EGFR, HER2, retinoblastoma, extracellular signal-regulated kinase-1/2, and protein kinase B/Akt in A549 cells, but not in NCI-H23 cells. Our results indicated that increased levels of constitutive EGFR/HER2 heterodimers were formed in A549 cells in the presence of ZD1839, whereas no heterodimer formation was detected in NCI-H23 cells. We therefore suggest that combination treatment with ZD1839 and trastuzumab might have improved therapeutic efficacy against NSCLC cells expressing both EGFR and HER2.
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PMID:Cooperative cell-growth inhibition by combination treatment with ZD1839 (Iressa) and trastuzumab (Herceptin) in non-small-cell lung cancer. 1625 59

Cisplatin (Platinol; Bristol-Myers Squibb, Princeton, NJ, http://www.bms.com) and carboplatin (Paraplatin; Bristol-Myers Squibb), together with newer chemotherapies, such as docetaxel (Taxotere; Aventis Pharmaceuticals Inc., Bridgewater, NJ, http://www.aventispharma-us.com), paclitaxel (Taxol; Bristol-Myers Squibb), vinorelbine (Navelbine; GlaxoSmith-Kline, Philadelphia, http://www.gsk.com), pemetrexed (Alimta; Eli Lilly and Company, Indianapolis, http://www.lilly.com), and gemcitabine (Gemzar; Eli Lilly and Company), have improved treatment outcomes in both advanced non-small cell lung cancer (NSCLC) and in the adjuvant/neoadjuvant setting. Newer systemic treatments for NSCLC, used in advanced stage IV management, are beginning to be studied in earlier stages of the disease, when treatment is better tolerated and potentially curative. Hopefully, newer agents with proven efficacies in advanced disease will enhance curability. Following the successful addition of bevacizumab (Avastin; Genentech, Inc., South San Francisco, CA, http://www.gene.com) to carboplatin/paclitaxel in advanced disease, bevacizumab is now being incorporated into adjuvant and neoadjuvant trials. Trials in stage IB-IIIA patients will study neoadjuvant docetaxel/cisplatin/bevacizumab. The discovery that patients with exon 19 and 21 mutations in the epidermal growth factor receptor gene EGFR have around an 80% response rate to gefitinib (Iressa; AstraZeneca Pharmaceuticals, Wilmington, DE, http:// www.astrazeneca-us.com) and that this response confers survival benefit indicates its potential utility for mutation-positive patients with advanced- and earlier-stage disease. Clinical characteristics, such as never smoking status and adenocarcinoma, and especially bronchioloalveolar carcinoma histological features, can also identify individuals likely to respond to EGFR tyrosine kinase inhibitors. Studies of neoadjuvant erlotinib (Tarceva; OSI Pharmaceuticals, Inc., Melville, NY, http://www.osip.com) in operable NSCLC are planned. One such study includes cisplatin and docetaxel. Effective development of active agents and disease management based on molecular profiling of lung tumors will change tomorrow's standard of care.
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PMID:How today's developments in the treatment of non-small cell lung cancer will change tomorrow's standards of care. 1627 56

Activation of the epidermal growth factor receptor (EGFR) and downstream signaling pathways, such as phosphatidylinositol-3 kinase/Akt and Ras/mitogen-activated protein kinase (MAPK), have been implicated in causing resistance to EGFR-targeted therapy in solid tumors, including the urogenital tumors. To investigate the mechanism of resistance to EGFR inhibition in bladder cancer, we compared EGFR tyrosine kinase inhibitor (Gefitinib, Iressa, ZD1839) with respect to its inhibitory effects on three kinases situated downstream of EGFR: MAPK, Akt, and glycogen synthase kinase-3beta (GSK-3beta). We found that the resistance to the antiproliferative effects of gefitinib, in vitro as well as in vivo in nude mice models, was associated with uncoupling between EGFR and MAPK inhibition, and that GSK-3beta activation and degradation of its target cyclin D1 were indicators of a high cell sensitivity to gefitinib. Further analysis of one phenotypic sensitive (253J B-V) and resistant (UM-UC13) cell lines revealed that platelet-derived growth factor receptor-beta (PDGFRbeta) activation was responsible for short circuiting the EGFR/MAPK pathway for mitogenic stimuli. However, invasion as well as actin dynamics were efficiently reduced by EGFR inhibition in UM-UC13. Chemical disruption of signaling pathways or of PDGFR kinase activity significantly reduced the inactive pool of cellular GSK-3beta in UM-UC13 cells. In conclusion, our data show that the uncoupling of EGFR with mitogenic pathways can cause resistance to EGFR inhibition in bladder cancer. Although this uncoupling may arise through different mechanisms, we suggest that the resistance of bladder cancer cells to EGFR blockade can be predicted early in the course of treatment by measuring the activation of GSK-3beta and of nuclear cyclin D1.
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PMID:Uncoupling between epidermal growth factor receptor and downstream signals defines resistance to the antiproliferative effect of Gefitinib in bladder cancer cells. 1628 45

To understand how type I and II endometrial tumors uniquely respond to tyrosine kinase inhibitor treatments, we evaluated the signaling pathways of epidermal growth factor (EGF) receptor (EGFR) under the effects of EGF and Iressa (ZD1839, gefitinib) using Ishikawa H and Hec50co cells that model type I and II endometrial carcinomas, respectively. The cells were assayed for the expression of EGFR and both cell lines express an average of 100,000 EGFR per cell; however, Ishikawa H cells express higher levels of HER-2/neu compared with Hec50co cells (1.38 x 10(5) compared with 2.04 x 10(4), respectively). Using the Kinetworks multi-immunoblotting approach, which profiles 31 signaling phosphoproteins, the most striking result was that Hec50co cells show a higher number of basal phosphorylated sites compared with Ishikawa H cells. Furthermore, we identified targets of Iressa treatment in both cell lines. Iressa, at a dose of 1 micromol/L, blocked the autophosphorylation of EGFR in Ishikawa H and Hec50co cells with some distinctive effects on downstream effectors. Nevertheless, in both cell lines, EGF stimulated and Iressa blocked the major EGFR target mitogen-activated protein kinases extracellular signal-regulated kinase 1 and 2 equally. The high basal phosphorylation of numerous signaling molecules in Hec50co cells that were not inhibited by Iressa indicates that other growth factor pathways are active in addition to EGFR. We conclude that endometrial cancer cells that model type I and II carcinomas have the capacity to respond to EGFR inhibition as a therapeutic strategy; however, the response of the more aggressive type II tumors may be limited by the constitutive activation of other signaling pathways.
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PMID:Regulation of signaling phosphoproteins by epidermal growth factor and Iressa (ZD1839) in human endometrial cancer cells that model type I and II tumors. 1637 4

Gefitinib exhibits antitumor activity in patient with non-small cell lung cancer (NSCLC). However, only 10-20% of patients exhibit clinical response to this drug. The molecular mechanisms underlying gefitinib sensitivity remain unknown. Peroxisome proliferators-activated receptor-gamma (PPAR-gamma) plays roles in the regulation of cellular differentiation and growth. This regulation was mediated by increasing Phosphatase and tensin homologue deleted on chromosome Ten (PTEN) levels. PTEN plays a role in the modulation of the phosphatidylinositol 3-kinase pathway (PI3K), which is involved in cell proliferation and survival. This study investigated the effects of PPAR-gamma agonist (rosiglitazone) on the expression of PTEN, as well as EGFR tyrosine kinase inhibitor (gefitinib)'s antitumor activity in A549 cells. The treatment of A549 cells with rosiglitazone reduced the growth of A549 cells in a dose-dependent manner, and facilitated the anti-proliferative effects of gefitinib. PPAR-gamma and PTEN expression were found to have increased in the gefitinib- and rosiglitazone-treated cells. This suggests that PPAR-gamma agonist (rosiglitazone) potentiated gefitinib's anti-proliferative effects by increased of PTEN expression, and suggest that PPAR-gamma ligands may serve as potential therapeutic agents for NSCLC.
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PMID:PPAR-gamma agonist increase gefitinib's antitumor activity through PTEN expression. 1638 27

Several monoclonal antibodies directed against EGFR are currently in clinical evaluation and include notably the agent cetuximab (C225). Tyrosine kinase inhibitors have chemical structures close to that of ATP and are thus ATP competitors on the tyrosine kinase site (ATP pocket) which is located in the intracellular domain of EGFR (gefitinib and erlotinib, respectively Tarceva and Iressa being the most advanced in clinical development). Well-conducted experimental studies open the way to new clinical applications with the most rewarding currently being the association between cetuximab and irinotecan. The two approaches of EGFR targeting have the same target and similar intracellular molecular impacts but they may differ under several aspects. For instance for the mechanism of action where, for monoclonal antibodies, there is a potential complement of cytotoxic activity brought by the ADCC phenomenon (antibody-directed cell cytotoxicity). One of the main current questions about the clinical use of anti-EGFR drugs is to dispose of faithful predictors for identifying tumors sensitive to this targeted treatment. The agents targeting VEGF are conceptually the same to those applied to EGFR. A major therapeutic advance brought by antiangiogenic drugs in colorectal cancer is attributable to bevacizumab. Bevacizumab is a monoclonal antibody impacting VEGF itself. A controlled clinical trial recently conducted on more than 800 advanced colorectal cancer patients concluded to a significant improvement in both response rate and global survival. This trial was comparing the combination 5FU-leucovorin-bevacizumab to 5FU-leucovorin and the advantage was in favor of the triple combination.
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PMID:[Pharmacological skills for targeting EGFR and VEGF]. 1638 65

It was reported that the parathyroid gland hyperplasia correlated with enhanced co-expression of TGF-alpha and its receptor EGFR at early stages of renal failure. This time, we investigated the time course for EGFR and its ligands, TGF-alpha, and EFG expression, and the influence of high-phosphorus (P) diet to EGFR and EGF expression, and the effect of EGFR-tyrosine kinase inhibitor (Gefitinib, [IRESSA; AstraZeneca]; TKI) in rat PTGs with established stage of renal failure. The levels of EGFR, EGF, TGF-alpha mRNA in rat PTGs were increased for the time periods. The serum intact PTH levels, and EGFR, EGFmRNA in rat PTGs were suppressed in normal-P diet group. Nuclei positive cells for PCNA in TKI group were suppressed. The levels of p21mRNA were increased in TKI group. These results suggested that the enhanced expression of EGFR, TGF-alpha and EGF participate in the cell proliferation of hyperplastic PTGs in established stage of renal failure.
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PMID:[Enhanced expression of EGFR, TGF-alpha, EGF in hyperplastic parathyroid glands in established stage of renal failure in rats]. 1641 40


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