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)

During the past ten years, the improvements of our understanding of cellular signal transduction pathways provide new targets for drug therapies. Chronic myeloid leukemia (CML), a malignant hematopoietic stem cell disorder, is characterised by an acquired genetic abnormality: the Philadelphia chromosome (Ph) and its molecular counterpart, the oncogene BCR-ABL. The latter, which is translated in an active BCR-ABL protein, exhibited a deregulated tyrosine kinase activity inducing malignant transformation. Produced from the 2-phenylaminopyrimidine class, a novel synthetic inhibitor, identified as CGP57148 (STI571), inhibits tyrosine kinase activity of c-ABL, BCR-ABL, PDGF-R and c-kit at micromolar concentrations. It suppresses the proliferation of the majority of BCR-ABL positive cell lines. The phases I-II clinical trials in CML have demonstrated promising results, especially in the chronic phase of the disease. STI571 is an original therapeutic approach which may be used as a model for the development of other drugs in cancer.
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PMID:[Leukemogenesis and new therapy development: the example of chronic myelogenous leukemia]. 1149 16

In order to define genetic determinants of primary and metastatic melanoma cell susceptibility to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL), we have applied oligonucleotide microarrays to TRAIL-sensitive primary T1 cells and TRAIL-resistant metastatic G1 cells treated or not with TRAIL. T1 and G1 cells are isogenic melanoma cell subclones. We examined 22 000 spots, 4.2% of which displayed differential expression in G1 and T1 cells. Cell susceptibility to TRAIL-mediated apoptosis was found to be correlated with gene expression signatures in this model. Some of the differentially expressed genes were identified as involved in ATP-binding and signaling pathways, based on previously published data. Further analysis provided evidences that c-kit was overexpressed in G1 cells while it was absent in T1 cells. The c-kit inhibitor, imatinib, did not restore TRAIL sensitivity, excluding a role for c-kit in TRAIL resistance in G1 cells. Surprisingly, imatinib inhibited cell proliferation and TRAIL-mediated apoptosis in melanoma cells. We investigated the possible involvement of several molecules, including c-ABL, platelet-derived growth factor receptor (PDGFR), cellular FADD-like interleukin-1 alpha-converting enzyme-like inhibitory protein (c-FLIP)(L/S), Fas-associated DD kinase, p53, p21(WAF1), proteins of B-cell leukemia/lymphoma 2 (Bcl-2) family and cytochrome c. Imatinib did not modulate the expression or activation of its own targets, such as c-ABL, PDGFRalpha and PDGFRbeta, but it did affect the expression of c-FLIP(L), BCL2-associated X protein (Bax) and Bcl-2. Moreover, c-FLIP(L) knockdown sensitized T1 cells to TRAIL-mediated apoptosis, with a sensitivity similar to that of cells previously treated with imatinib. More notably, we found that the resistance to TRAIL in G1 cells was correlated with constitutive c-FLIP(L) recruitment to the DISC and the inhibition of caspase 8, 3 and 9 processing. Moreover, c-FLIP(L) knockdown partly restored TRAIL sensitivity in G1 cells, indicating that the expression level of c-FLIP(L) and its interaction with TRAIL receptor2 play a crucial role in determining TRAIL resistance in metastatic melanoma cells. Our results also show that imatinib enhances TRAIL-induced cell death independently of BH3-interacting domain death agonist translocation, in a process involving the Bax:Bcl-X(L) ratio, Bax:Bcl-X(L)/Bcl-2 translocation, cytochrome c release and caspase activation. Our data indicate that imatinib sensitizes T1 cells by directly downregulating c-FLIP(L), with the use of an alternative pathway for antitumor activity, because PDGFRalpha is not activated in T1 cells and these cells do not express c-kit, c-ABL or PDGFRbeta. Caspase cascade activation and mitochondria also play a key role in the imatinib-mediated sensitization of melanoma cells to the proapoptotic action of TRAIL.
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PMID:Imatinib enhances human melanoma cell susceptibility to TRAIL-induced cell death: Relationship to Bcl-2 family and caspase activation. 1698 47

The phenylaminopyrimidine-derivate Imatinib mesylate has been developed for targeted inhibition of the Abelson kinase (c-ABL), which is constitutively activated when translocated to the genetic locus of the breakpoint cluster region (leading to the BCR/ABL fusion gene), thereby forming the causative pathogenetic event for the development of chronic myeloid leukemia (CML). Of note, due to its physico-chemical properties, kinase specificity of Imatinib is limited. Despite of its well documented clinical efficacy mediated by inhibition of constitutively activated tyrosine kinases such as BCR/ABL in CML, PDGF-RA in HES and mutated c-kit in GIST patients, other tyrosine kinases such as Flt-3, Lck and mitogen-activated kinases (MAPK) are affected as well. Accordingly, it has recently been shown that therapeutic doses of Imatinib also target a variety of immune cells, e.g. by modulating the differentiation of dendritic cells (DC) as well as by impeding proper T-cell and macrophage function. In contrast, combining Imatinib with Interleukin 2 (IL-2) potently activates NK-cells and led to the description of a new subclass of DC, so-called IK-DC. The latter mediate Imatinib/IL-2-induced regression of tumors in pre-clinical animal models via production of high amounts of IFN-gamma and the death receptor ligand TRAIL. Thus, Imatinib exerts potent immuno-modulatory effects in vitro and in vivo, which will be discussed together with their clinical relevance in detail throughout this review.
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PMID:The kinase inhibitor imatinib--an immunosuppressive drug? 1750 22