Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P10721 (c-kit)
 6,575 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

With the development of targeted therapeutics, especially for small-molecule inhibitors, it is important to understand whether the observed in vivo efficacy correlates with the modulation of desired/intended target in vivo. We have developed a small-molecule inhibitor of all three vascular endothelial growth factor (VEGF) receptors (VEGFR), platelet-derived growth factor receptor, and c-Kit tyrosine kinases, pazopanib (GW786034), which selectively inhibits VEGF-induced endothelial cell proliferation. It has good oral exposure and inhibits angiogenesis and tumor growth in mice. Because bolus administration of the compound results in large differences in C(max) and C(trough), we investigated the effect of continuous infusion of a VEGFR inhibitor on tumor growth and angiogenesis. GW771806, which has similar enzyme and cellular profiles to GW786034, was used for these studies due to higher solubility requirements for infusion studies. Comparing the pharmacokinetics by two different routes of administration (bolus p.o. dosing and continuous infusion), we showed that the antitumor and antiangiogenic activity of VEGFR inhibitors is dependent on steady-state concentration of the compound above a threshold. The steady-state concentration required for these effects is consistent with the concentration required for the inhibition of VEGF-induced VEGFR2 phosphorylation in mouse lungs. Furthermore, the steady-state concentration of pazopanib determined from preclinical activity showed a strong correlation with the pharmacodynamic effects and antitumor activity in the phase I clinical trial.
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PMID:Pharmacokinetic-pharmacodynamic correlation from mouse to human with pazopanib, a multikinase angiogenesis inhibitor with potent antitumor and antiangiogenic activity. 1762 Apr 31

Developments in the knowledge of molecular biology of renal cell carcinoma (RCC) over the past 20 years have been identified. Angiogenesis is playing a key role in the physiopathology of RCC. Von Hippel-Lindau (VHL) alterations, HIFalpha accumulation and vascular endothelial growth factor (VEGF) overexpression are important mediators of this process. Several stategies have been developped to target angiogenesis for the treatment of metastatic RCC. These include inhibition of VEGF receptors (inhibition of the tyrosine kinase activity) or binding to the VEGF protein. Several additional kinases inhibitions including PDGF receptors are also targeted. Sunitinib (SU11248) is an orally biovailable small molecule that has demonstrated superiority over interferon-alpha for the treatment of metastatic RCC. In a recent randomized phase III study conducted in 750 patients, the response rate to sunitinib was 31% and to interferon 6%. The median of progression free survival (PFS) was 11 months for sunitinib and 5 months for interferon (p < 0.001). Sorafenib (BAY43-9006) was found to inhibit Raf1, but also VEGFR2 and 3, Flt3, PDGFR-a and b and c-kit, has been tested in a phase III study against placebo after one prior systemic therapy. The median of the time to progression (TTP) for sorafenib was 24 weeks versus 12 weeks for patients in the placebo arm (p = 0,01). Other molecules tested in metastatic RCC will be presented including axitinib, pazopanib and bevacizumab.
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PMID:[Angiogenesis and renal cell carcinoma]. 1784 9

Early in mammalian development, the stem cell leukemia (SCL/TAL1) gene and its distinct 3' enhancer (SCL 3'En) specify bipotential progenitor cells that give rise to blood and endothelium, thus termed hemangioblasts. We have previously detected a minor population of SCL (+) cells in the postnatal kidney. Here, we demonstrate that cells expressing the SCL 3'En in the adult kidney are comprised of CD45+CD31- hematopoietic cells, CD45-CD31+ endothelial cells and CD45-CD31- interstitial cells. Creation of bone marrow chimeras of SCL 3'En transgenic mice into wild-type hosts shows that all three types of SCL 3'En-expressing cells in the adult kidney can originate from the bone marrow. Ischemia/reperfusion injury to the adult kidney of SCL 3'En transgenic mice results in the intrarenal elevation of SCL and FLK1 mRNA levels and of cells expressing hem-endothelial progenitor markers (CD45, CD34, c-Kit and FLK1). Furthermore, analysis of SCL 3'En in the ischemic kidneys reveals an increase in the abundance of SCL 3'En-expressing cells, predominantly within the CD45 (+) hematopoietic fraction and to a lesser extent in the CD45 (-) fraction. Our results suggest organ-injury-induced reactivation of bone marrow-derived hemangioblasts and possible local angioblastic progenitors expressing SCL and SCL 3'En.
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PMID:Organ-injury-induced reactivation of hemangioblastic precursor cells. 1789 90

The neovascularization of tissues is accomplished by two distinct processes: de novo formation of blood vessels through the assembly of progenitor cells during early prenatal development (vasculogenesis), and expansion of a pre-existing vascular network by endothelial cell sprouting (angiogenesis), the main mechanism of blood vessel growth in postnatal life. Evidence exists that adult bone marrow (BM)-derived progenitor cells can contribute to the formation of new vessels by their incorporation into sites of active angiogenesis. Aim of this study was to investigate the in vitro self-organizing capacity of human BM mononuclear cells (BMMNC) to induce vascular morphogenesis in a three-dimensional (3D) matrix environment in the absence of pre-existing vessels. Whole BMMNC as well as the adherent and non-adherent fractions of BMMNC were embedded in fibrin gels and cultured for 3-4 weeks without additional growth factors. The expression of hematopoietic-, endothelial-, smooth muscle lineage, and stem cell markers was analyzed by immunohistochemistry and confocal laser-scanning microscopy. The culture of unselected BMMNC in 3D fibrin matrices led to the formation of cell clusters expressing the endothelial progenitor cell (EPC) markers CD133, CD34, vascular endothelial growth factor receptor (VEGFR)-2, and c-kit, with stellar shaped spreading of peripheral elongated cells forming tube-like structures with increasing complexity over time. Cluster formation was dependent on the presence of both adherent and non-adherent BMMNC without the requirement of external growth factors. Developed vascular structures expressed the endothelial markers CD34, VEGFR-2, CD31, von Willebrand Factor (vWF), and podocalyxin, showed basement-membrane-lined lumina containing CD45+ cells and were surrounded by alpha-smooth muscle actin (SMA) expressing mural cells. Our data demonstrate that adult human BM progenitor cells can induce a dynamic self organization process to create vascular structures within avascular 3D fibrin matrices suggesting a possible alternative mechanism of adult vascular development without involvement of pre-existing vascular structures.
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PMID:Vascular morphogenesis by adult bone marrow progenitor cells in three-dimensional fibrin matrices. 1817 24

Targeted therapies by means of compounds that inhibit a specific target molecule represent a new perspective in the treatment of cancer. In contrast to conventional chemotherapy which acts on all dividing cells generating toxic effects and damage of normal tissues, targeted drugs allow to hit, in a more specific manner, subpopulations of cells directly involved in tumor progression. Molecules controlling cell proliferation and death, such as Tyrosine Kinase Receptors (RTKs) for growth factors, are among the best targets for this type of therapeutic approach. Two classes of compounds targeting RTKs are currently used in clinical practice: monoclonal antibodies and tyrosine kinase inhibitors. The era of targeted therapy began with the approval of Trastuzumab, a monoclonal antibody against HER2, for treatment of metastatic breast cancer, and Imatinib, a small tyrosine kinase inhibitor targeting BCR-Abl, in Chronic Myeloid Leukemia. Despite the initial enthusiasm for the efficacy of these treatments, clinicians had to face soon the problem of relapse, as almost invariably cancer patients developed drug resistance, often due to the activation of alternative RTKs pathways. In this view, the rationale at the basis of targeting drugs is radically shifting. In the past, the main effort was aimed at developing highly specific inhibitors acting on single RTKs. Now, there is a general agreement that molecules interfering simultaneously with multiple RTKs might be more effective than single target agents. With the recent approval by FDA of Sorafenib and Sunitinib--targeting VEGFR, PDGFR, FLT-3 and c-Kit--a different scenario has been emerging, where a new generation of anti-cancer drugs, able to inhibit more than one pathway, would probably play a major role.
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PMID:From single- to multi-target drugs in cancer therapy: when aspecificity becomes an advantage. 1828 97

Stem cells are self-renewing multipotent progenitors with the broadest developmental potential in a given tissue at a given time. Normal stem cells in the adult organism are responsible for renewal and repair of aged or damaged tissue. Adult stem cells are present in virtually all tissues and during most stages of development. In this review, we introduce the reader to the basic information about the field. We describe selected stem cell isolation techniques and stem cell markers for various stem cell populations. These include makers for endothelial progenitor cells (CD146/MCAM/MUC18/S-endo-1, CD34, CD133/prominin, Tie-2, Flk1/KD/VEGFR2), hematopoietic stem cells (CD34, CD117/c-Kit, Sca1), mesenchymal stem cells (CD146/MCAM/MUC18/S-endo-1, STRO-1, Thy-1), neural stem cells (CD133/prominin, nestin, NCAM), mammary stem cells (CD24, CD29, Sca1), and intestinal stem cells (NCAM, CD34, Thy-1, CD117/c-Kit, Flt-3). Separate section provides a concise summary of recent clinical trials involving stem cells directed towards improvement of a damaged myocardium. In the last part of the review, we reflect on the field and on future developments.
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PMID:Adult stem cells and their trans-differentiation potential--perspectives and therapeutic applications. 1862 66

Pancreatic stem cells (PSC) have proved their high plasticity by differentiating into cell types of all three germ layers after the formation of organoid bodies. Motivated by this high differentiation potential this study focused on the immanent stem cell, endothelial and epithelial characteristics of PSC to elucidate whether PSC are a possible source for a stem cell-based in vitro model for screening of pharmaceutical substances. Furthermore, it was investigated whether marker expression was influenced by application of protocols for inducing endothelial or epithelial differentiation originating from research with mesenchymal stem cells or by cultivation on extracellular matrices (ECM). PSC showed expression of relevant stem cell markers CD 45, nestin, Oct 4 and c-kit. As endothelial characteristics they displayed the markers endoglin, VCAM 1, VEGFR 1 and vWF as well as the formation of vessel-like structures. Those endothelial properties were not further intensified by application of protocols employing vascular endothelial growth factor (VEGF), basic fibroblastic growth factor (bFGF) and endothelial cell growth medium. As typical epithelial characteristics PSC showed expression of keratin 7, 8, 18 and 19, ZO-1 and catenin beta1. In order to induce epithelial differentiation PSC were cocultured with the lung epithelial cell lines A549 and Calu-3 either by the usage of conditioned medium or by cultivation of PSC on fixed epithelial cells. Depending on the applied coculture system and epithelial cell type used expression of the epithelial marker cadherin-1 was altered compared to control. Cultivation on different ECM changed expression of all investigated markers only marginally. These results confirm that PSC possess endothelial and epithelial properties. Furthermore, epithelial characteristics represented by expression of CDH 1 were altered by coculture with epithelial cell lines.
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PMID:Differentiation potential of human pancreatic stem cells for epithelial- and endothelial-like cell types. 1869 69

Bone and soft tissue sarcomas are an infrequent and heterogeneous group of mesenchymal tumors, including more than a hundred different entities attending to histological patterns. Sarcomas are quite resistant to conventional chemotherapy (anthracycline and ifosfamide) with the exception of some subtypes, such as Ewing's sarcoma (ES). New drugs with proved efficacy against sarcomas include taxanes, gemcitabine, and ET-743. Preclinical studies have also identified key molecular events leading to the progression and development of sarcomas which are good candidates to targeted therapy. Inhibitors of the tyrosine kinase receptors, such as IGF-1R, c-kit, PDGFR, VEGFR, or the mTOR signaling pathway, proteasome, angiogenesis, and stress response proteins are under clinical evaluation against sarcomas. ES, a tumor characterized by chromosomal translocations that originate gene fusions (EWS-FLI1, EWS-ERG), is an example of a good chemotherapy responder tumor whose survival rate shows a plateau in recent years. Preclinical studies have identified that new targets such as HSP90 are of relevance to ES. On the other hand, recent studies showed the role of cancer stem cells (CSCs) in sarcomas and the relevance of the identification of reliable molecular markers and possible therapeutic targets. New therapeutic approaches could be directed against CSCs. This review describes more recent targeted therapy in sarcomas, with special emphasis on ES and the role of CSCs. We also emphasize the role of high throughput proteomic techniques in identifying new therapeutic targets.
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PMID:Targeting sarcomas: therapeutic targets and their rational. 1901 96

Despite the emerging success of multi-targeted protein tyrosine kinase (PTK) inhibitors in cancer therapy, significant side effects and resistance concerns seems to be avoided unlikely. The aim of the present study was to identify novel multi-targeting PTK inhibitors. The kinase enzymatic activities were measured by enzyme-linked immunosorbent assay (ELISA). The antiproliferative activities in human microvascular endothelial cells (HMECs) were evaluated by sulforhodamine (SRB) assay. The phosphorylation of kinases and their downstream molecules was probed by western blot analysis. The binding mode between MdOS and PTKs was profiled by surface plasmon resonance (SPR) approach and molecular simulation. Tube formation assay, rat aortic ring method and chicken chorioallantoic membrane assay were combined to illustrate the in vitro and in vivo anti-angiogenic effects. Results indicated that MdOS, a novel marine-derived oligosaccharide sulfate, exhibited a broad-spectrum PTK inhibitory action. At an enzymatic level, MdOS inhibited HER2, EGFR, VEGFR, PDGFR, c-Kit, FGFR1 and c-Src, with little impact on FGFR2. In cellular settings, MdOS inhibited phosphorylation of PTKs, exemplified by HER2, EGFR and VEGFR2, and downstream molecules of Erk1/2 and AKT. Further studies demonstrated that MdOS acted as an ATP-competitive inhibitor via directly binding to the residues of entrance rather than those of the ATP-binding pocket. Furthermore, MdOS inhibited proliferation and tube formation of HMECs, arrested microvessel outgrowth of rat aortic rings and hindered the neovascularization of chick allantoic membrane. Taken together, results presented here indicated that MdOS exhibited anti-angiogenic activity in a PTK-dependent manner and make it a promising agent for further evaluation in PTK-associated cancer therapy.
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PMID:The marine-derived oligosaccharide sulfate (MdOS), a novel multiple tyrosine kinase inhibitor, combats tumor angiogenesis both in vitro and in vivo. 1902 Jun 61

Pazopanib, which is being developed by GlaxoSmithKline plc, is an oral, second-generation multi-targeted tyrosine kinase inhibitor that targets VEGFR, platelet-derived growth factor receptor and c-kit, key proteins responsible for tumor growth and survival. Pazopanib exhibited good potency against all of the human VEGFRs and closely related tyrosine receptor kinases in vitro, and demonstrated antitumor activity in several human tumor xenografts, including renal cell carcinoma (RCC), and breast and lung cancer. In phase I and II clinical trials, pazopanib was generally well tolerated with the main side effects being hypertension, fatigue or gastrointestinal disorders. Pazopanib alone caused a decrease in tumor size and stable disease in a significant number of patients, including those with RCC, NSCLC and gynecological tumors. The combination of pazopanib with lapatinib was effective in patients with breast cancer. At the time of publication, pazopanib monotherapy was being evaluated in phase III trials in patients with RCC and as combination therapy with lapatinib in patients with breast cancer. In addition, phase I and II trials were being conducted to assess pazopanib alone or in combination with a range of chemotherapeutics in patients with solid tumors or multiple myeloma.
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PMID:Pazopanib, a VEGF receptor tyrosine kinase inhibitor for cancer therapy. 1903 39


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