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

We have previously found that the 4-[4-(N-substituted carbamoyl)-1-piperazinyl]-6,7-dimethoxyquinazolines can function as potent and selective inhibitors of platelet-derived growth factor receptor (PDGFR) phosphorylation. A series of highly potent, specific, orally active, small molecule kinase inhibitors directed against members of PDGFR receptor have been developed through modifications of the novel quinazoline template I. Systematic modifications in the A-bicyclic ring and D-rings of protype I were carried out to afford potent analogues, which display IC(50) values of <250 nM in cellular betaPDGFR phosphorylation assays. An optimized analogue in this series, 75 (CT53518), inhibits Flt-3, betaPDGFR, and c-Kit receptor phosphorylation with IC(50) values of 50-200 nM, whereas 15-20-fold less potent activity against CSF-1R was observed. This analogue also inhibits autophosphorylation of Flt-3 ligand-stimulated wild-type Flt-3 and a constitutively activated Flt-3/internal tandem duplication (ITD) with IC(50) values of 30-100 nM. Through this optimization process, 75 was found to be metabolically stable and has desirable pharmacokinetic properties in all animal species studied (F% > 50%, T(1/2) > 8 h). Oral administration of 75 promotes mice survival and significantly delayed disease progression in a Flt-3/ITD-mediated leukemia mouse model and shows efficacy in a nude mouse model of chronic myelomonocytic leukemia.
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PMID:Identification of orally active, potent, and selective 4-piperazinylquinazolines as antagonists of the platelet-derived growth factor receptor tyrosine kinase family. 1216 50

The hematopoietic class III receptor tyrosine kinase (RTK) Flt3 (Flk2, STK1) has recently received much attention as a potential drug target. Activation of Flt3 by different types of mutations plays an important role for proliferation, resistance to apoptosis, and prevention of differentiation of leukemic blasts in acute myeloid leukemia (AML). At least one type of such mutations - an internal tandem duplication in the Flt3 juxtamembrane domain (Flt3-ITD) - has been associated with an unfavorable prognosis. Signal transduction of Flt3 involves activation of several conserved pathways, including the RAS/MAP-Kinase and the phosphoinositide-3-kinase/Akt signaling cascades. Transforming versions of Flt3 exhibit altered signaling, for example a very pronounced activation of STAT5, ultimately resulting in alternate profiles of gene expression and cell transformation. Selective inhibitors of Flt3 tyrosine kinase activity have the potential to suppress aberrant Flt3 signaling. Although highly homologous to other class III RTKs, Flt3 is resistant to the phenylaminopyrimidine STI571 (Gleevec, Imatinib), a potent inhibitor of other RTKs in the family, such as the PDGFbeta-receptor or c-Kit. STI571 binding to Flt3 is prevented by the phenylalanine 691 side-chain in the ATP binding center and mutating this site to threonine renders the corresponding Flt3 mutant sensitive to STI571. Compounds of several other structural families, including the quinoxaline AG1296, the bis(1H-2-indolyl)-1-methanone D-65476, the indolinones SU5416 and SU11248, the indolocarbazoles PKC412 and CEP-701, and the piperazonyl quinazoline CT53518, are potent inhibitors of Flt3 kinase. They exhibit different selectivity profiles, both with respect to other kinases and among wildtype Flt3 and its activated versions. These compounds hold promise as novel drugs against AML and as probes for understanding activation mechanisms and signaling pathways in the class III RTK family.
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PMID:Flt3 receptor tyrosine kinase as a drug target in leukemia. 1518 May 25

We report the structure-activity relationship of quinoline and quinazoline derivatives, which include urea, thiourea, urethane, and acylthiourea groups, as inhibitors of the platelet-derived growth factor (PDGF) receptor autophosphorylation. Our previous studies showed that the quinoline and quinazoline derivatives including urea, thiourea, and carbamate groups were highly potent compounds as the PDGF receptor autophosphorylation inhibitor, but these compounds did not exhibit receptor selectivity between the PDGF receptor and the c-kit receptor. As a result of further synthesis and biological evaluation, we have found that the quinoline and quinazoline-acylthiourea derivatives showed not only good inhibitory activity for the PDGF receptor but also receptor selectivity between the PDGF receptor and the c-kit receptor. Furthermore N-{4-[(6,7-dimethoxy-4-quinolyl)oxy]phenyl}-N'-(2-methylbenzoyl)thiourea exhibited potent oral efficacy in in vivo assay using the rat carotid balloon injury model. Therefore, the quinoline and quinazoline-acylthiourea derivatives may be expected to have potential as therapeutic agents for the treatment of restenosis.
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PMID:Identification of potent and selective inhibitors of PDGF receptor autophosphorylation. 1657 Sep 14

The c-Kit receptor can activate distinct signaling pathways including phosphoinositide 3-kinase (PI3K)/Akt and mTOR. Aberrant c-Kit activation protects cells from apoptosis and enhances invasion of colon carcinoma cells. Tandutinib is a novel quinazoline-based inhibitor of the type III receptor tyrosine kinases including c-Kit. We determined the effect of tandutinib on colon cancer growth and identified a mechanism of action. Tandutinib inhibited phosphorylation of c-Kit, Akt, mTOR, and p70S6 kinase. In addition, tandutinib significantly inhibited the proliferation and colony formation ability of colon cancer cell lines but did not affect normal colonic epithelial cells. There were increased levels of activated caspase-3 and Bax/Bcl2 ratio, coupled with a reduction in cyclin D1, suggesting apoptosis. There was also a downregulation of COX-2, VEGF, and interleukin-8 expression, suggesting effects on cancer-promoting genes. In addition, overexpressing constitutively active Akt partially suppressed tandutinib-mediated colon cancer cell growth. In vivo, intraperitoneal administration of tandutinib significantly suppressed growth of colon cancer tumor xenografts. There was a reduction in CD31-positive blood vessels, suggesting that there was an effect on angiogenesis. Tandutinib treatment also inhibited the expression of cancer-promoting genes COX-2 and VEGF and suppressed the activation of Akt/mTOR signaling proteins in the xenograft tissues. Together, these data suggest that tandutinib is a novel potent therapeutic agent that can target the Akt/mTOR/p70S6K signaling pathway to inhibit tumor growth and angiogenesis.
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PMID:Tandutinib inhibits the Akt/mTOR signaling pathway to inhibit colon cancer growth. 2342 97

Several regulatory and signaling molecules governing angiogenesis are targets of interest for the development of drugs in the cancer, including growth factors such as Vascular Endothelial Growth Factor (VEGF) and Platelet-Derived Growth Factor (PDGF). A series of 4-aryloxy-6,7-dimethoxyquinazolines, previously synthesized in our laboratory, has shown a nanomolar inhibition of kinase enzymatic activity of VEGFR, PDGFR and c-Kit. We have therefore studied the impact of the variation in the 7-position substitution of the quinazoline core. Substitution by aminoalkoxy chains led to new highly potent ATP-competitive inhibitors of VEGFR, PDGFR and c-Kit enzyme with IC50 values in the nanomolar range and this substitution has increased greatly antiproliferative activity on cancer cell lines (PC3, MCF7, HT29) and HUVEC (human umbilical vein endothelial cells). One of the most promising compounds (36) was assessed for its ability to limit the induction of web like network of capillary tubes by the human umbilical vascular endothelial cells (HUVEC) and for its ability to inhibit invasion.
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PMID:Inhibition of tumor cell growth and angiogenesis by 7-aminoalkoxy-4-aryloxy-quinazoline ureas, a novel series of multi-tyrosine kinase inhibitors. 2474 48