Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0022116 (ischemia)
 91,303 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Genome-wide screening using a small interfering RNA (siRNA) library has revealed novel molecules that are involved in a wide range of physiological responses. The expression of vascular endothelial growth factor (VEGF) is increased under hypoxic conditions, and plays a crucial role in tumor angiogenesis and tissue responses to ischemia. Here, we used a siRNA expression vector library to elucidate molecules that modify VEGF expression. Screening using an siRNA library revealed that MAPKKK6 (MEKK6/MAP3K6) regulates VEGF expression under both normoxic and hypoxic conditions in vitro, although the biological function of MAP3K6 remains unknown. Attenuation of VEGF expression by MAP3K6 inhibition was demonstrated by transient transfection of double-stranded RNA as well as by stable transfection of short hairpin RNA-expressing vectors against MAP3K6. Conditioned medium of MAP3K6-knocked down cells attenuated both endothelial proliferation and capillary network formation in a VEGF-dependent manner in vitro. In addition, tumor cells with down-regulation of MAP3K6 expression showed significant suppression of tumor growth in vivo, which was accompanied by significant repression of vessel formation and VEGF expression in these tumors. The results of this study suggest that MAP3K6 regulates VEGF expression in both normoxia and hypoxia, and that regulation of VEGF by MAP3K6 may play a crucial role in both angiogenesis and tumorigenesis.
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PMID:Mitogen-activated protein 3 kinase 6 mediates angiogenic and tumorigenic effects via vascular endothelial growth factor expression. 1924 38

Hypoxia and inflammation are coincidental events in a diverse range of disease states including tumor growth, ischemia, and chronic inflammation. Hypoxia contributes to the development of inflammation, at least in part through the activation and/or potentiation of NF-kappaB, a master regulator of genes involved in innate immunity, inflammation, and apoptosis. NF-kappaB can be activated through two distinct signaling pathways termed the canonical and noncanonical pathways, respectively. The canonical pathway is activated through the IKKalpha/beta/gamma complex, while the noncanonical pathway involves NIK-mediated activation of IKKalpha homodimers. In the current study, we have investigated the relative roles of these two pathways in hypoxia-dependent NF-kappaB activation. Lymphotoxin alpha1beta2 (LTalpha1beta2) activated both the canonical and noncanonical NF-kappaB signaling pathways in HeLa cells. Sustained hypoxia enhanced basal and LTalpha1beta2-induced NF-kappaB activity in a manner that was dependent upon the canonical but not the noncanonical signaling pathway. Intermittent hypoxia activated NF-kappaB in a manner that was also primarily dependent upon the canonical pathway. Knockdown of the p65 subunit of the canonical NF-kappaB pathway was sufficient to abolish the effects of hypoxia on LTalpha1beta2-induced NF-kappaB activity. Furthermore, in synovial biopsies obtained at arthroscopy from patients with active inflammatory arthritis, the canonical pathway was preferentially activated in those patents with lower joint pO2 values. In summary, we hypothesize that hypoxia enhances NF-kappaB activity primarily through affecting the canonical pathway.
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PMID:Hypoxia activates NF-kappaB-dependent gene expression through the canonical signaling pathway. 1942 87

A(2B) adenosine receptors are increasingly recognized as important orchestrators of inflammation. A(2B) receptor activation promotes the inflammatory response of mast cells, epithelial cells, smooth muscle cells and fibroblasts, thereby contributing to the pathophysiology of asthma and colitis. A(2B) receptor stimulation limits endothelial cell inflammatory responses and permeability and suppresses macrophage activation thereby preventing tissue injury after episodes of hypoxia and ischemia. A(2B) receptor stimulation also promotes the production of angiogenic cytokines by endothelial cells, mast cells and dendritic cells, aiding granuloma tissue formation and inflammatory resolution, but can also contribute to tumor growth. A(2B) receptors are, thus, potentially important pharmacological targets in treating immune system dysfunction and inflammation.
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PMID:A(2B) adenosine receptors in immunity and inflammation. 1942 67

Prostate cancer tumor growth and neovascularization is promoted by an interplay between migratory tumor stromal cells such as specialized tumor-associated macrophages (TAMs) and circulating endothelial precursor cells (CEPs). As vehicles for tumor therapy, human CEPs are relatively easy to isolate from peripheral blood, are able to proliferate long-term in vitro, are amenable to viral manipulation, and preferentially home to regions of ischemia found in growing tumors. We show here that human peripheral blood CEPs expanded ex vivo migrate to prostate cancer cells in vitro and efficiently home to human prostate tumor xenografts in vivo. Infection of precursors ex vivo with an adenovirus constructed to secrete a soluble form of the colony-stimulating factor-1 receptor CD115 that inhibits macrophage viability and migration in vitro significantly decreases the number of TAMs in xenografts (p < .05), reduces proliferation (p < .01) and vascular density (p < .03), and suppresses the growth of xenografts (p < .03). These data show for the first time that targeting stromal cell processes with cellular therapy has the potential to retard prostate tumor growth.
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PMID:Adenoviral-mediated endothelial precursor cell delivery of soluble CD115 suppresses human prostate cancer xenograft growth in mice. 1952 14

Dysregulation or mislocalization of cell adhesion molecules and their regulators, such as E-cadherin, beta-catenin, and alpha-catenin, usually correlates with loss of polarity, dedifferentiation, invasive tumor growth, and metastasis. A subpopulation of alpha-catenin-negative cells within the DLD-1 colorectal carcinoma cell line causes it to display a heterogeneous morphological makeup, thus providing an excellent model system in which to investigate the role of alpha-catenin in tumorigenesis. We re-established expression of alpha-catenin protein in an alpha-catenin-deficient subpopulation of the DLD-1 cell line and used it to demonstrate that loss of alpha-catenin resulted in increased in vitro tumorigenic characteristics (increased soft agarose colony formation, clonogenic survival after suspension, and survival in suspension). When the cells were used to form tumor xenografts, those lacking alpha-catenin showed faster growth rates because of increased cellular cycling but not increased tumor microvascular recruitment. alpha-Catenin-expressing cells were preferentially located in well perfused areas of xenografts when tumors were formed from mixed alpha-catenin-positive and -negative cells. We therefore evaluated the role of the ischemic tumor microenvironment on alpha-catenin expression and demonstrated that cells lose expression of alpha-catenin after prolonged exposure in vitro to hypoglycemic conditions. Our findings illustrate that the tumor microenvironment is a potent modulator of tumor suppressor expression, which has implications for localized nutrient deficiency and ischemia-induced cancer progression.
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PMID:Modulation of the tumor suppressor protein alpha-catenin by ischemic microenvironment. 1974 64

Angiogenesis has an essential role in promoting and supporting tumor growth and it is an important therapeutic target. The tumor vascular network is the result of pro-angiogenic and inhibitory factors as well as of the interaction between endothelial cells and extracellular matrix. Different antiangiogenic therapeutics have been developed to improve tumor control through vascular-targeting agents (VTA). VTAs can be divided into two groups: antiangiogenic agents and vascular-disrupting agents (VDAs). VTAs inhibit specific factors required to induce and direct the angiogenic process, with major activity against small tumor masses and at the tumor periphery, encompassing monoclonal antibodies and small molecules inhibitors of the tyrosine kinase domain of the VEGF receptor. VDAs specifically target and destroy well-established tumor vessels with ischemia and destruction of large masses with central hemorrhagic necrosis and survival of a thin peripheral tumor layer. VDAs can be divided into biologics, such as ligand-based, and small-molecule agents; this second group includes small-molecule VDAs like flavonoids, such as 5,6-dimethylxanthenone-4-acetic acid (DMXAA), and microtubule-destabilizing agents. In this review we will discuss the mechanism of action, as well as the preclinical and clinical results, of one of the most promising antitubulin agents: the combretastatin A4-phosphate derivative, AVE8062A.
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PMID:AVE8062: a new combretastatin derivative vascular disrupting agent. 1975 9

Adenosines, endogenous purine nucleosides, appear in the extracellular space under metabolically stressful conditions associated with ischemia, inflammation, and cell damage. Their activity on innate immunity is prevalently inhibitory and can develop both in infectious and neoplastic diseases. During cancer development, tumor cells that release high concentrations of adenosines can impair the function of tumor-infiltrating lymphocytes and assist tumor growth by neo-angiogenesis. We evaluated the influence of A(2) adenosine receptor (A(2)AR) agonist on cytotoxic-cell response comparing human with other mammalian species (rodents, pigs, goats), both in healthy and in cancer conditions. The A(2)AR agonist developed dose-dependent inhibition of the cytotoxic activity of immune effector cells in all studied species. However, variability of the response was observed in relation to the species and the target cells that were used. Altogether, our data indicate that the A(2)AR plays a central role in adenosine-mediated inhibition of immune response to tumors.
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PMID:NK cell-mediated cytotoxicity modulation by A(2) adenosine receptor agonist in different mammalian species. 1982 26

Vascularization and vascular remodeling represent critical adaptive responses to tissue hypoxia that are mediated by hypoxia-inducible factor 1 (HIF-1). In patients with peripheral arterial disease, these responses are impaired by aging and diabetes, leading to critical limb ischemia and amputation. Intramuscular injection of an adenovirus encoding a constitutively active form of the HIF-1alpha subunit (CA5) increases the recovery of blood flow following femoral artery ligation in a mouse model of age-dependent critical limb ischemia. Intradermal injection of a plasmid encoding CA5 promotes healing of cutaneous wounds in a mouse model of diabetes. In cancer, vascularization is required for tumors to grow beyond microscopic size, a process that involves HIF-1-dependent production of angiogenic growth factors. Daily treatment of prostate cancer xenograft-bearing mice with low-dose anthracycline (doxorubicin or daunorubicin) chemotherapy inhibits HIF-1 DNA-binding activity, HIF-1-dependent expression of angiogenic growth factors, mobilization of circulating angiogenic cells, and tumor vascularization, thereby arresting tumor growth.
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PMID:Regulation of vascularization by hypoxia-inducible factor 1. 1984 1

Heterocyclic indazole derivatives are claimed in patent WO2008138448 as inhibitors of the serum- and glucocorticoid-inducible-kinase 1 (SGK1) and drugs for the pharmacological treatment of SGK1-related diseases, such as diabetes, obesity, metabolic syndrome, systemic and pulmonary hypertension, cardiac fibrosis, hypertrophy and insufficiency, arteriosclerosis, glomerulosclerosis, nephrosclerosis, nephritis, nephropathy, deranged electrolyte excretion, fibrosing and inflammatory disease (e.g., liver cirrhosis, lung fibrosis, rheumatism, arthrosis, Crohn s disease, chronic bronchitis, radiation fibrosis, sclerodermia, cystic fibrosis, scar formation and Alzheimer' disease), tumor growth, peptic ulcers and some disorders hitherto not conclusively shown to involve SGK1. Most of the claims are supported by the literature. SGK1 is ubiquitously expressed and its expression is stimulated by hyperglycemia, cell shrinkage, ischemia, glucocorticoids, mineralocorticoids and several inflammatory mediators including TGF-ss. SGK1 is activated by insulin and growth factors via the phosphatidylinositol-3-kinase pathway. SGK1 regulates ion channels (including ENaC, KCNE1/KCNQ1), carriers (including NCC, NHE3, SGLT1), Na(+)/K(+)-ATPase, enzymes (including glycogen-synthase-kinase-3) and transcription factors (including FOXO3a, ss-catenin, NF-kappaB). A gain-of-function SGK1 gene variant, carried by approximately 3 - 5% of Caucasians and approximately 10% of Africans, is associated with increased blood pressure, obesity and type 2 diabetes. In vitro and in vivo experiments suggested a critical role of SGK1 in renal fluid retention and hypertension, glucose-induced obesity, coagulation and increased matrix protein formation.
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PMID:Heterocyclic indazole derivatives as SGK1 inhibitors, WO2008138448. 2002 Dec 89

Breast cancer progression depends upon the elaboration of a vasculature sufficient for the nourishment of the developing tumor. Breast tumor cells frequently contain a mutant form of p53 (mtp53), a protein which promotes their survival. The aim of this study was to determine whether combination therapy targeting mtp53 and anionic phospholipids (AP) on tumor blood vessels might be an effective therapeutic strategy for suppressing advanced breast cancer. We examined the therapeutic effects, singly, or in combination, of p53 reactivation and induction of massive apoptosis (PRIMA-1), which reactivates mtp53 and induces tumor cell apoptosis, and 2aG4, a monoclonal antibody that disrupts tumor vasculature by targeting AP on the surface of tumor endothelial cells and causes antibody-dependent destruction of tumor blood vessels, leading to ischemia and tumor cell death. Xenografts from two tumor cell lines containing mtp53, BT-474 and HCC-1428, were grown in nude mice to provide models of advanced breast tumors. After treatment with PRIMA-1 and/or 2aG4, regressing tumors were analyzed for vascular endothelial growth factor (VEGF) expression, blood vessel loss, and apoptotic markers. Individual drug treatment led to partial suppression of breast cancer progression. In contrast, combined treatment with PRIMA-1 and 2aG4 was extremely effective in suppressing tumor growth in both models and completely eradicated approximately 30% of tumors in the BT-474 model. Importantly, no toxic effects were observed in any treatment group. Mechanistic studies determined that PRIMA-1 reactivated mtp53 and also exposed AP on the surface of tumor cells as determined by enhanced 2aG4 binding. Combination treatment led to significant induction of tumor cell apoptosis, loss of VEGF expression, as well as destruction of tumor blood vessels. Furthermore, combination treatment severely disrupted tumor blood vessel perfusion in both tumor models. The observed in vitro PRIMA-1-induced exposure of tumor epithelial cell AP might provide a target for 2aG4 and contribute to the increased effectiveness of such combination therapy in vivo. We conclude that the combined targeting of mtp53 and the tumor vasculature is a novel effective strategy for combating advanced breast tumors.
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PMID:Targeting mutant p53 protein and the tumor vasculature: an effective combination therapy for advanced breast tumors. 2034 29


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