Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04626 (erbB-2)
 5,251 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A subpopulation of cells was derived from the Hs431 connective tissue sarcoma cell line which possessed high affinity (estimated Kd = 0.38-0.55 nM) binding sites for human recombinant [125I]-IL-1 alpha. Binding at 4 degrees C was slow approaching equilibrium by 4 hrs. Dissociation of [125I]-IL-1 alpha was also slow and unaffected by high concentrations of cold ligand. The binding site also underwent ligand-induced internalization at 37 degrees C. An Mr = 83,000 protein was identified in affinity crosslinking studies. Despite these similarities to previously reported IL-1 receptors, Hs431 cells did not exhibit biological responses to IL-1 which have been observed in other cell lines. IL-1 did not induce PGE2 or collagenase synthesis. IL-1 also failed to induce ornithine decarboxylase activity (ODC) or stimulate [3H]-thymidine incorporation. In contrast, the Hs431 cells did contain a functional epidermal growth factor (EGF) receptor as determined from binding studies, protein kinase activity, induction of ODC, and stimulation of [3H]-thymidine incorporation. Thus, the refractoriness of Hs431 cells to IL-1 was fairly specific and did not result from a generalized defect associated with cell transformation.
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PMID:Characterization of a high affinity interleukin-1 (IL-1) specific binding site in a human synovial sarcoma (Hs431) cell line. 216 29

The oncoprotein HER-2/neu is a prosurvival factor and its overexpression has been correlated with adverse prognosis in breast cancers. High levels of the cyclooxygenase-2 (COX-2), a proinflammatory and antiapoptotic enzyme, were detected in HER-2-positive tumors and this observation was linked to an HER-2-mediated induction of COX-2 gene transcription. Here, we report that COX-2 expression, and synthesis of its major enzymatic product, PGE2, leads in turn to an enhanced HER-2 expression. Moreover, COX-2 enzymatic inhibition dramatically reduced HER-2 protein levels, efficiently increased the cancer cells sensitility to chemotherapeutic treatment and acted in synergy with HER-2 inhibitor, trastuzumab. Therefore, we propose an original model where HER-2 and COX-2 transcriptionally regulate each other in a positive loop.
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PMID:Regulation of HER-2 oncogene expression by cyclooxygenase-2 and prostaglandin E2. 1498 3

Cyclooxygenase (COX)-2-derived prostaglandins (PGs) are thought to contribute to tumor growth and resistance to radiation therapy. COX-2 protein expression is increased in many tumors including those of the breast. COX-2-derived PGs have been shown to protect cells from radiation damage. This study evaluated the role of COX-2-derived PG in radiation treatment by using the NMF11.2 mammary tumor cell line originally obtained from HER-2/neu mice that overexpress HER-2/neu. We determined whether the effects of the COX-2 inhibitor SC236 on cell growth, radiation-induced PGE2 production and COX expression, cell cycle redistribution, and vascular endothelial growth factor (VEGF) were acting through COX-2-dependent mechanisms. The NMF11.2 cells expressed both COX-1 and COX-2 protein and mRNA. The radiation treatment alone led to a dose-dependent increase in the levels of COX-2 mRNA and COX-2 protein, which was associated with an increase in the production of PGE2 and prostacyclin (PGI2). Treating NMF11.2 cells with high concentrations (20 microM) of SC236 for 48 h reduced the radiation-induced increase in COX-2 activity and also decreased cell growth. SC236 (20 microM) increased the accumulation of the cells in the radiosensitive G2-M phase of the cell cycle. However, a low concentration (5 microM) of SC236 was adequate to reduce COX-2 activity. The lower concentration of SC236 (5 microM) also decreased cell growth after a longer incubation period (96 h) and, in combination with a 2 or 5 Gy dose, led to an accumulation of cells in G2-M phase. Restoring PG to control values in cells treated with 5 microM SC236 prevented the growth inhibition and G2-M cell cycle arrest. Radiation treatment of NMF11.2 cells also increased VEGF protein expression and VEGF secretion in a dose-dependent manner, which was blocked in those cells pretreated with 20 microM SC236 but not in those pretreated with 5 microM SC236. These findings indicate that the COX-2 inhibitor SC236 reduced cell growth and arrested cells in the G2-M phase of the cell cycle by mechanisms that are both dependent and independent of PG production while its effects on VEGF appear to be independent of COX-2.
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PMID:Cyclooxygenase (COX)-2-dependent effects of the inhibitor SC236 when combined with ionizing radiation in mammary tumor cells derived from HER-2/neu mice. 1507 85

Prostaglandins (PGs) such as PGE2 enhance proliferation in many cells, apparently through several distinct mechanisms, including transactivation of the epidermal growth factor (EGF) receptor (EGFR) as well as EGFR-independent pathways. In this study we found that in primary cultures of rat hepatocytes PGE2 did not induce phosphorylation of the EGFR, and the EGFR tyrosine kinase blockers gefitinib and AG1478 did not affect PGE2-stimulated phosphorylation of ERK1/2. In contrast, PGE2 elicited EGFR phosphorylation and EGFR tyrosine kinase inhibitor-sensitive ERK phosphorylation in MH1C1 hepatoma cells. These findings suggest that PGE2 elicits EGFR transactivation in MH1C1 cells but not in hepatocytes. Treatment of the hepatocytes with PGE2 at 3 h after plating amplified the stimulatory effect on DNA synthesis of EGF administered at 24 h and advanced and augmented the cyclin D1 expression in response to EGF in hepatocytes. The pretreatment of the hepatocytes with PGE2 resulted in an increase in the magnitude of EGF-stimulated Akt phosphorylation and ERK1/2 phosphorylation and kinase activity, including an extended duration of the responses, particularly of ERK, to EGF in PGE2-treated cells. Pertussis toxin abolished the ability of PGE2 to enhance the Akt and ERK responses to EGF. The results suggest that in hepatocytes, unlike MH1C1 hepatoma cells, PGE2 does not transactivate the EGFR, but instead acts in synergism with EGF by modulating mitogenic mechanisms downstream of the EGFR. These effects seem to be at least in part G(i) protein-mediated and include upregulation of signaling in the PI3K/Akt and the Ras/ERK pathways.
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PMID:Prostaglandin E2 upregulates EGF-stimulated signaling in mitogenic pathways involving Akt and ERK in hepatocytes. 1765 93