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)

Numerous inhibitors of angiogenesis are currently under study in lung cancer. Four trials of adjuvant interferon after chemotherapy for small cell lung cancer (SCLC) were negative. Several metalloproteinase inhibitors (MMPIs) are now in study in SCLC and non-small cell lung cancer (NSCLC). Two large randomized trials have closed recently in which Marimastat 10 mg bid was compared to placebo in responding patients with SCLC. Two randomized studies of Prinomastat versus placebo with combination chemotherapy in advanced NSCLC have also completed accrual. The results of these trials are not yet available, but should be reported in mid-2001. A Phase III trial of BMS-275291, a broad-spectrum MMPI in combination with paclitaxel and carboplatin is open for patients with advanced NSCLC. Neovastat, a standardized shark cartilage extract is under study in inoperable Stage III NSCLC. VEG-F gene expression is increased in many tumors including NSCLC, and may act as a paracrine mediator of growth. A randomized Phase II trial of paclitaxel and carboplatin with or without a recombinant humanized anti-VEG-F has been undertaken in NSCLC. Modestly better response and survival were seen with anti-VEG-F and a large Phase III trial is planned. Numerous receptor tyrosine kinases (TK) have been found to be directly or indirectly involved in angiogenesis including Flk-1, Flt-l, Tie-1 and Tie-2. SU5416 is a small molecular TK inhibitor and potent inhibitor of VEG-F-mediated Flk-1 receptor signaling. Another TK inhibitor SU6668 blocks VEG-F, bFGF and PDGF receptor signaling. It is orally available, and it may be evaluated in lung cancer trials in the near future. ZD4190 is an inhibitor of KDR/Flk-1 that may be evaluated in SCLC. Thalidomide has recently been shown in pre-clinical models to be anti-angiogenic. A randomized trial of paclitaxel/carboplatin and radiation with or without thalidomide is open for patients with Stage IIIB NSCLC in the United States. Numerous other anti-angiogenesis agents are in early clinical trials, but have not been evaluated in lung cancer yet.
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PMID:Angiogenesis inhibitors in the treatment of lung cancer. 1174 Sep 99

Apart from endothelial cells, the receptor tyrosine kinase TEK/Tie-2 is also expressed by primitive hematopoietic stem cells. While the role of this receptor and its ligand angiopoietin-1 (ang-1) during angiogenesis has been intensively studied before, little is known about their function in normal or malignant hematopoiesis. Recently several studies suggested that TEK plays an important role in the proliferation of primitive hematopoietic cells. We, therefore, analyzed blood cells of healthy donors and leukemia patients for expression of TEK and ang-1 by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR) and Northern blotting. We found an increased expression of the receptor and its ligand in 11 of 17 cases of acute and chronic myeloid leukemia (CML) but not in four lymphocytic leukemias or five myeloid leukemias in remission. Abundant ang-1 message could also be detected in 4/6 myeloid and 1/9 cell lines of lymphocytic origin, but only one cell line co-expressed the TEK receptor, suggesting that ang-1 and TEK were probably expressed by different subsets of cells in the leukemic samples. Recently, several studies have indicated that angiogenic factors like ang-1 and vascular endothelial growth factor can enhance the proliferation of normal and malignant hematopoietic cells. The expression of both the TEK receptor and its ligand in acute myeloid leukemia (AML) and CML patients might, therefore, suggest an involvement of these genes in the pathogenesis of myeloproliferative disorders.
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PMID:Expression of angiopoietin-1 and its receptor TEK in hematopoietic cells from patients with myeloid leukemia. 1175 66

Vascular development and its transformation are necessary for successful hemochorial placentation, and vascular endothelial growth factor (VEGF), angiopoietins, and their receptors may be involved in the molecular regulation of this process. To determine the potential role of these putative regulators in a widely studied primate, the common marmoset, we investigated their mRNA expression and protein location in the placenta throughout pregnancy using in situ hybridization, Northern blot analysis, and immunocytochemistry. VEGF was localized in decidual and cytotrophoblast cells, and its highest expression was found in the maternal decidua. The Flt receptor was exclusively detected in the syncytial trophoblast with increasing expression in placentae from 10 wk to term. Soluble Flt (sFlt) was also detectable by Northern blot analysis. KDR receptor expression was restricted to mesenchymal cells during early placentation and to the fetoplacental vasculature during later placentation. KDR expression increased throughout pregnancy. Angiopoietin-1 (Ang-1) was localized in the syncytial trophoblast, being highly expressed in the second half of gestation. Ang-2 mRNA localized exclusively to maternal endothelial cells, and was highly expressed in 10-wk placentae. The Tie-2 receptor was found in cytotrophoblast cells and in fetal and maternal vessels. High Tie-2 levels were detected in the wall of chorion vessels at 14-wk, 17-wk, and term placentae. These results suggest that the processes of trophoblast invasion, maternal vascular transformation, and fetoplacental vascular differentiation and development are regulated by the specific actions of angiogenic ligand-receptor pairs. Specifically, 1) VEGF/Flt and Ang-1/Tie-2 may promote trophoblast growth, 2) VEGF/KDR and Ang-1/Tie-2 may support fetoplacental vascular development and stabilization, 3) sFlt may balance VEGF actions, and 4) Ang-2/Tie-2 may remodel the maternal vasculature.
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PMID:Hemochorial placentation in the primate: expression of vascular endothelial growth factor, angiopoietins, and their receptors throughout pregnancy. 1187 89

We have previously shown that 4-anilinoquinazolines can be potent inhibitors of vascular endothelial growth factor (VEGF) receptor (Flt-1 and KDR) tyrosine kinase activity. A novel subseries of 4-anilinoquinazolines that possess basic side chains at the C-7 position of the quinazoline nucleus have been synthesized. This subseries contains potent, nanomolar inhibitors of KDR (median IC(50) 0.02 microM, range 0.001-0.04 microM), which are comparatively less potent vs Flt-1 tyrosine kinase (median IC(50) 0.55 microM, range 0.02-1.6 microM). The compounds also retain some inhibitory activity against the tyrosine kinase associated to the endothelial growth factor receptor (EGFR) (median IC(50) 0.2 microM, range 0.075-0.8 microM) but demonstrate selectivity vs that associated to the FGF receptor 1 (median IC(50) 2.5 microM, range 0.9-19 microM). This selectivity profile is also evident in a growth factor-stimulated human endothelial cell (HUVEC) proliferation assay (i.e., inhibition of VEGF > EGF > FGF), with inhibition of VEGF-induced proliferation being achieved at nanomolar concentrations (median IC(50) 0.06 microM). Further examination of compound 2 (ZD6474) in recombinant enzyme assays revealed excellent selectivity for the inhibition of KDR tyrosine kinase (IC(50) 0.04 microM) vs the kinase activity of erbB2, MEK, CDK-2, Tie-2, IGFR-1R, PDK, PDGFRbeta, and AKT (IC(50) range: 1.1 to >100 microM). Anilinoquinazolines possessing basic C-7 side chains exhibited markedly improved aqueous solubility over previously described anilinoquinazolines possessing neutral C-7 side chains (up to 500-fold improvement at pH 7.4). In addition, aqueous solubility of the neutral fraction present at pH 7.4 of the basic subseries of anilinoquinazoline proved to be higher than that of the neutral analogue 1 (ZD4190). Oral administration of representative compounds to mice (50 mg/kg) produced plasma levels between 0.2 and 3 microM at 24 h after dosing. Our development candidate 2 demonstrated a very attractive in vitro profile combined with excellent solubility (330 microM at pH 7.4) and good oral bioavailability in rat and dog (> 80 and > 50%, respectively). This compound demonstrated highly significant, dose-dependent, antitumor activity in athymic mice. Once daily oral administration of 100 mg/kg of compound 2 for 21 days inhibited the growth of established Calu-6 lung carcinoma xenografts by 79% (P < 0.001, Mann Whitney rank sum test), and substantial inhibition (36%, P < 0.02) was evident with 12.5 mg/kg/day.
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PMID:Novel 4-anilinoquinazolines with C-7 basic side chains: design and structure activity relationship of a series of potent, orally active, VEGF receptor tyrosine kinase inhibitors. 1188 99

From collagenase digests of human thyroid, endothelial cells were separated from follicular cells by their greater adherence to gelatin-coated plates. Endothelial cells were further purified using fluorescence-activated cell sorting, selecting for cells expressing factor VIII-related antigen. Isolated cells were negative for thyroglobulin and calcitonin when examined by immunostaining. The receptor for the angiopoietins, Tie-2, was expressed by the cells, and expression was increased by agents that elevate cAMP. Nitric oxide synthase (NOS) 3, the endothelial form of NOS, was expressed by the cells and similarly regulated. Cells responded strongly to the mitogen fibroblast growth factor (FGF)-2 in growth assays but only weakly to vascular endothelial growth factor (VEGF). VEGF was, however, able to stimulate nitric oxide release from the cells consistent with their endothelial origin. The FGF receptor (FGFR1) was full length (120 kDa) and immunolocalized to the cytosol and nucleus. Thyrotropin (TSH) did not regulate FGFR1, but its expression was increased by VEGF. Thrombospondin, a product of follicular cells, was a growth inhibitor, but neither TSH nor 3,5,3'-triiodothyronine had direct mitogenic effects. Thyroid follicular cell conditioned medium contained plasminogen activator activity and stimulated the growth of the endothelial cells, but when treated with plasminogen to produce the endothelial-specific inhibitor, angiostatin, growth was inhibited. Human thyroid endothelial cell cultures will be invaluable in determining the cross talk between endothelial and follicular cells during goitrogenesis.
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PMID:Isolation and characterization of human thyroid endothelial cells. 1962 78

The large capillary mass of the newborn lung demands the presence of endothelial cell precursors in lung tissue before development of the pulmonary capillary bed. The objective of this investigation was to isolate and characterize putative endothelial cell precursors from developing human lung. CD34, a cell surface marker for hematopoietic progenitor cells, endothelial precursor cells, and small vessel endothelial cells, was employed as an immunological "handle" for the selection of the desired cells. When CD34+ cells were isolated from midtrimester human fetal lung tissue, then maintained in culture, the isolated cells expressed immunoreactivity for the endothelial cell marker von Willebrand factor and the vascular endothelial growth factor receptors KDR and Flt-1. However, only 5% or fewer of the cells expressed PECAM, an important factor in cell-cell interactions and a marker for endothelial cells associated with vessels. The CD34+ cells endocytosed acetylated low-density lipoprotein and formed capillary-like structures when incubated in a cushion of Matrigel. RT-PCR analysis of mRNA for endothelial cell-related proteins Flt-1, Tie-2, and endothelial nitric oxide synthase demonstrated expression of these mRNAs by the isolated cells for at least 16 cell passages. These observations demonstrate that capillary endothelial cell precursors can be isolated from developing human lung and maintained in cell culture. These cells represent a potentially important tool for investigating the regulation of mechanisms governing development of the air-blood barrier in the human lung.
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PMID:Characterization of CD34+ cells isolated from human fetal lung. 1238 36

Angiogenesis occurs in skeletal muscle in response to exercise training. To gain insight into the regulation of this process, we evaluated the mRNA expression of factors implicated in angiogenesis over the course of a training program. We studied sedentary control (n = 17) rats and both sedentary (n = 18) and exercise-trained (n = 48) rats with bilateral femoral artery ligation. Training consisted of treadmill exercise (4 times/day, 1-24 days). Basal mRNA expression in sedentary control muscle was inversely related to muscle vascularity. Angiogenesis was histologically evident in trained white gastrocnemius muscle by day 12. Training produced initial three- to sixfold increases in VEGF, VEGF receptors (KDR and Flt), the angiopoietin receptor (Tie-2), and endothelial nitric oxide synthase mRNA, which dissipated before the increase in capillarity, and a substantial (30- to 50-fold) but transient upregulation of monocyte chemoattractant protein 1 mRNA. These results emphasize the importance of early events in regulating angiogenesis. However, we observed a sustained elevation of the angiopoietin 2-to-angiopoietin 1 ratio, suggesting continued vascular destabilization. The response to exercise was (in general) tempered in high-oxidative muscles. These findings place importance on cellular events coupled to the onset of angiogenesis.
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PMID:Angiogenic growth factor expression in rat skeletal muscle in response to exercise training. 1254 34

Solitary fibrous tumor (SFT) is an uncommon tumor first reported in the pleura, but recently described in other tissues. CD34, which is expressed in hematopoietic stem cells, endothelial progenitor cells and vascular endothelial cells, is observed in most SFT and some investigators believe that its expression is a definitive marker of this tumor. In the present study, the expression of vascular endothelial cell markers, such as vascular endothelial growth factor receptor (VEGFR)-1 (flt-1), VEGFR-2 (flk-1/KDR), Tie-2 and c-Met, was examined in SFT to clarify the relationship between SFT and endothelial cells. By immunohistochemical staining of tumor cells from 26 patients, VEGFR-1 was detected in 24 (92%), VEGFR-2 in five (19%), Tie-2 in 14 (54%), and c-Met, a specific receptor of hepatocyte growth factor (HGF) in 23 patients (88%). Furthermore, VEGFR-3 (flt-4) immunoreactivity was detected in eight of 26 patients (31%). In contrast, VEGF, VEGF-C and HGF, which are ligands for the receptors, were not localized in the SFT cells. These findings indicate that most SFT may closely relate to vascular or lymphatic endothelial cells and the endothelial growth factors may contribute to the growth of SFT in a paracrine manner.
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PMID:Immunohistochemical localization of endothelial cell markers in solitary fibrous tumor. 1258 46

Vectors based on the adeno-associated virus (AAV) deliver therapeutic genes to muscle and heart at high efficiency and maintain transgene expression for long periods of time. Here we report about the synergistic effect on blood vessel formation of AAV vectors expressing the 165 aa isoform of vascular endothelial growth factor (VEGF165), a powerful activator of endothelial cells, and of angiopoietin-1 (Ang-1), which is required for vessel maturation. High titer AAV-VEGF165 and AAV-Ang-1 vector preparations were injected either alone or in combination in the normoperfused tibialis anterior muscle of rats. Long term expression of VEGF165 determined massive cellular infiltration of the muscle tissues over time, with the formation of a large set of new vessels. Strikingly, some of the cells infiltrating the treated muscles were found positive for markers of activated endothelial precursors (VEGFR-2/KDR and Tie-2) and for c-kit, an antigen expressed by pluripotent bone marrow stem cells. Expression of VEGF165 eventually resulted in the formation of structured vessels surrounded by a layer of smooth muscle cells. Presence of these arteriolae correlated with significantly increased blood perfusion in the injected areas. Co-expression of VEGF165 with angiopoietin-1-which did not display angiogenic effect per se-remarkably reduced leakage of vessels produced by VEGF165 alone.
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PMID:Induction of functional neovascularization by combined VEGF and angiopoietin-1 gene transfer using AAV vectors. 1272 7

Vascular remodeling in host tissues surrounding growing tumors is implicated in the successful development of tumor neovasculature. Cooperation between vascular endothelial growth factor (VEGF) and angiopoietins (Angs) is considered to be critical in this context. However, the mechanisms regulating the coordinated expression of these molecules remain, to date, elusive. In this study, we used a murine ovarian cancer angiogenesis model induced by overexpression of VEGF, as well as 52 human ovarian cancer specimens and 36 established cancer cell lines to characterize the expression and regulation of Ang-2 in the context of tumor angiogenesis. Using a combination of immunohistochemistry, laser capture microdissection and real-time quantitative reverse transcription-PCR, we showed that tumor-derived VEGF significantly up-regulated the expression of Ang-2 in host stroma endothelial cells, resulting in markedly increased Ang-2/Tie-2 mRNA copy number ratio in vivo. In vitro experiments showed that VEGF directly up-regulated Ang-2, which is mediated via VEGF receptor-2/flk-1/KDR pathway, in cultured endothelial cells through transcriptional activation rather than the enhanced mRNA stability. In human ovarian cancer, Ang-2 was primarily expressed in stroma endothelial cells and detectable in tumor cells of only 12% tumor specimens; however, it was not detected in the majority of established ovarian cancer cell lines. In addition, a significant correlation was observed between VEGF and Ang-2 mRNA expression (P < 0.01) but not between VEGF and Ang-1 or Tie-2 in human ovarian cancer specimens. In the mouse ovarian cancer model, up-regulation of Ang-2 in host stroma endothelial cells was significantly associated with pericyte loss and instability of the host vasculature surrounding the tumor. Our study suggests a novel mechanism by which tumor-derived VEGF interacts with Angs/Tie-2 system in host stroma endothelial cells and induces in a paracrine manner the remodeling of host vasculature to support angiogenesis during tumor growth.
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PMID:Tumor-derived vascular endothelial growth factor up-regulates angiopoietin-2 in host endothelium and destabilizes host vasculature, supporting angiogenesis in ovarian cancer. 1281 Jun 77


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