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:2.7.10.2 (focal adhesion kinase)
44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Gastrointestinal stromal tumors (GISTs) are rare mesenchymal tumors of the gastrointestinal tract characterized by the expression of a receptor that activates tyrosine kinase called c-kit. Since malignant GISTs are resistant to conventional radiation therapy and chemotherapy, recurrent or malignant GIST has an extremely poor prognosis even after surgical resection. The development of a tyrosine kinase inhibitor, STI571 (imatinib mesylate, Glivec, Gleevec), which inhibits the BCR-ABL, PDGF-R alpha and c-kit receptors, has changed the management of unresectable malignant GIST and has improved the survival of patients with metastatic disease. We report a patient with GIST and diffused peritoneal metastases, whose tumor initially responded to STI571 and eventually became resistant. A 45-year-old woman underwent partial jejunostomy on September 3, 1998, under a diagnosis of submucosal tumor of the jejunum. Pathological examination of the primary tumor revealed a strong c-kit expression and GIST was diagnosed. The patient underwent an excision of peritoneal recurrences on October 31, 2000; April 17, 2001; and August 28, 2001. A treatment with STI571 (400 mg/day) was initiated on October 15, 2001, and she was free from peritoneal masses for 8 months after the fourth operation. However, the patient herself suspended the STI571 therapy for one month and multiple peritoneal metastases developed. Although the treatment with STI571 was restarted at 400 mg/day, the peritoneal masses did not respond this time. She died of liver, lung, and peritoneal metastases after the seventh cytoreductive operation on February 11, 2004. Several mechanisms of the resistance to STI571 have been identified. Amplification or an overexpression of KIT has been proposed to be involved in the resistance development. Several mutations of KIT were also correlated with the clinical outcome. Her tumors showed mutations in exons 9 or 11 of KIT, which had longer event-free and overall survival times than those tumors that had mutations of exons 13 or 17. In this case, an exon 11 mutation of KIT was initially noted. After the interruption of the treatment, an additional point mutation arose in exon 13 that caused a resistance to STI571. Currently STI571 is the first-line therapy for non-resectable GISTs, but a single-agent therapy often leads to tumor resistance. It is our hope that we will be able to design an alternative treatment to overcome such resistance.
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PMID:[A case of metastatic gastrointestinal stromal tumor developing a resistance to STI571 (imatinib mesylate)]. 1555 17

During the past year, crystal structures of the PDK-1, ITK, Aurora-A, c-KIT and FLT-3 protein kinases in complex with several ATP-competitive inhibitors have been determined. Some structures have crystallized in catalytically active conformations, whereas others appear to be in inactive or native conformations. The differences between these two classes of structures provide further understanding of how kinase activity may be self-regulated in the cellular environment and how phosphorylation can modulate signalling at a molecular level. All of these structures provide a basis for designing selective protein kinase inhibitors of use in the treatment of cancer and autoimmune disease.
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PMID:Novel protein kinases and molecular mechanisms of autoinhibition. 1558 94

Imatinib mesylate, an inhibitor of tyrosine kinases including BCR-ABL and KIT, inhibits the growth inhibition of small cell lung cancer (SCLC) cell lines in vitro. However, clinical trials of imatinib mesylate alone in patients with SCLC resulted in unsatisfactory outcomes. Vitamin K2 (menaquinone-4: VK2) induces apoptosis and differentiation in leukemia cells. We recently reported that VK2 also induces apoptosis in lung cancer cell lines. In the present study, we focused on the in vitro combined effects of imatinib mesylate plus VK2 on SCLC cell lines such as LU-139, LU-130, NCI-H69 and NCI-H128. Treatment with imatinib mesylate and VK2 for 96 h resulted in suppression of cell growth in a dose-dependent manner in all cell lines tested. The 50% inhibitory concentration (IC50) for imatinib mesylate ranged from 17-29 microM, whereas the IC50 for VK2 ranged from 16-64 microM. Combined treatment of imatinib mesylate plus VK2 resulted in pronounced inhibition of cell growth. The morphologic features of cells treated with imatinib mesylate and VK2 were typical of apoptosis. Since VK2 is a safe medicine without prominent adverse effects, treatment of patients with SCLC could derive therapeutic benefits from a combination of imatinib mesylate and VK2.
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PMID:Combination of vitamin K2 plus imatinib mesylate enhances induction of apoptosis in small cell lung cancer cell lines. 1558 22

Stem cell factor (SCF) and its receptor, KIT, are essential to the migration and differentiation of melanocytes during embryogenesis. We previously demonstrated that apoptosis is induced by blocking survival function of the SCF/KIT interaction in a mouse neural crest cell (NCC) primary culture. Using the NCCmelb4 cell line, we investigated the occurrence of apoptosis in the cultured cells when KIT receptors were blocked by the monoclonal anti-KIT antibody (ACK2). Apoptosis following treatment with ACK2 was detected by DNA fragmentation assay, in situ apoptosis detection, and electron microscopy. We noted a decrease in extracellular signal-related kinase (ERK) and ribosomal S6 kinase (RSK) protein expression following ACK2 incubation. Western blot analysis and real-time quantitative RT-PCR revealed an apparent time-dependent reduction in Bcl-2 protein levels with respect to ACK2 within the NCCmelb4 cells. In terms of Bax expression, a difference was not found. Fas and caspase8 proteins increased time-dependently in proportion to ACK2 incubation. We noted apoptotic cell death upon addition of ACK2, with evidence of possible involvement of Bcl-2 and Fas in the induction of apoptosis. In contrast, no significant correlation between Fas ligand (Fas-L) expression and ACK2 was found. Fas activation appears to occur independent of Fas-L during ACK2-induced cell death. Therefore, we propose that Fas-L expression in NCCmelb4 cells does not play a major role in facilitating apoptosis. Furthermore, we hypothesize that these molecules combined with SCF/KIT play an important role in regulating the induction of vertebrate NCC apoptosis during embryogenesis.
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PMID:Bcl-2 reduced and fas activated by the inhibition of stem cell factor/KIT signaling in murine melanocyte precursors. 1565 78

A study was undertaken to develop an acute myeloid leukaemia (AML) screening panel to uncover novel recurring gene mutations. Analysis was performed on six genes known to be mutated in AML (RUNX1, FLT3, KIT, CEBPA, PTPN11 and NRAS) and an additional two candidate genes (CCND3 and FES) in a panel of 175 primary human AML samples that included all French-American-British types except M3, and all cytogenetic risk groups. One hundred and fifteen mutations were identified in 97 (55%) patients comprising 81 patients (46%) with one mutation, 14 patients (8%) with two mutations and two patients (1%) with three mutations. Fifty-five of 88 (63%) patients with normal karyotype AML had at least one mutation. Correlation was observed between KIT mutation and 'favourable risk' cytogenetics (P <0.001), CEBPA mutation and 'intermediate risk' cytogenetics (P=0.045), and PTPN11 mutation and 'poor risk' disease (P <0.001). The frequency of individual gene mutation was in accordance with previously published studies. Three novel mutations of FLT3 were detected (Y589D, D839G, Y842H) that would have been overlooked by conventional gel electrophoresis. A 51-bp deletion was detected in CCND3 in a patient with normal karyotype AML. This validated panel now provides an important tool to evaluate other candidate genes in the genesis of myeloid malignancy.
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PMID:Development of a human acute myeloid leukaemia screening panel and consequent identification of novel gene mutation in FLT3 and CCND3. 1566 33

Imatinib mesylate is a potent and specific tyrosine kinase inhibitor against c-ABL, BCR-ABL, and c-KIT, and has been demonstrated to be highly active in chronic myeloid leukemia and gastrointestinal stromal tumors. We examined the antifibrotic effects of imatinib using a bleomycin-induced lung fibrosis model in mice because imatinib also inhibits tyrosine kinase of platelet-derived growth factor receptors (PDGFRs). Imatinib inhibited the growth of primary murine lung fibroblasts and the autophosphorylation of PDGFR-beta induced by PDGF. Administration of imatinib significantly prevented bleomycin-induced pulmonary fibrosis in mice, partly by reducing the number of mesenchymal cells incorporating bromodeoxyuridine. Analysis of bronchoalveolar lavage cells demonstrated that imatinib did not suppress early inflammation on Days 7 and 14 caused by bleomycin. These results suggest that imatinib has the potential to prevent pulmonary fibrosis by inhibiting the proliferation of mesenchymal cells, and that imatinib might be useful for the treatment of pulmonary fibrosis in humans.
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PMID:Imatinib as a novel antifibrotic agent in bleomycin-induced pulmonary fibrosis in mice. 1573 62

The hallmark characteristics of cancer include an unrestrained proliferation involving activation of growth signals, loss of negative regulation and dysfunctional apoptotic pathways. Targeting abnormal cell signalling pathways should provide a more selective approach to cancer treatment than conventional cytotoxic chemotherapy. Tyrosine kinases play an essential role in the signalling pathways involved in the control of cellular proliferation and growth. Imatinib is a small-molecule tyrosine kinase inhibitor of the ABL fusion gene, platelet derived growth factor receptors (PDGFR) and KIT. This agent has demonstrated considerable activity in chronic myeloid leukaemia (CML) by inhibiting the BCR-ABL fusion protein and gastrointestinal stromal tumours (GISTs), which are predominantly driven by activating mutations in KIT. A number of other rare conditions are also responsive, for example, dermatofibrosarcoma protuberans, which is driven by a chromosomal translocation involving PDGF-B and Col1A1, resulting in overexpression of PDGF-B, and hypereosinophillic syndrome, which can be caused by activating PDGFR mutations. The pivotal registration study for newly diagnosed CML was a large randomised trial comparing 400 mg/day of imatinib to a combination of IFN-alpha and cytarabine, which demonstrated a significantly higher complete haematological and cytogenetic response rate in the imatinib arm. In the case of GIST a randomised study in patients with inoperable or metastatic disease explored doses of 400 - 600mg and reported a response rate of > 50% in each arm plus disease stabilisation and an improvement in performance status. Large randomised trials have subsequently been performed, comparing 400 with 800mg/day. The first to report indicates that the larger dose is associated with improved progression-free survival, although it is not yet known whether or not this will translate into a difference in overall survival. The most common KIT mutation involves exon 11 and is associated with a statistically significant better response and prognosis compared with other mutations or no detectable mutations. Mutational analysis is likely to become increasingly important in the selection of patients for neoadjuvant and adjuvant treatment and in helping to understand the nature of acquired resistance.
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PMID:The development and application of imatinib. 1579 12

Conventional chemotherapeutic drugs are ineffective in treatment of gastrointestinal stromal tumors (GISTs). Imatinib (STI571, Gleevec, Glivec; Novartis Pharmaceuticals, East Hanover, NJ), a selective inhibitor of KIT, ABL, BCR-ABL, PDGFRA, and PDGFRB, represents a new paradigm of targeted cancer therapy and has revolutionized the treatment of patients with chronic myelogenous leukemia and GISTs. Unfortunately, imatinib resistance has emerged. The reported mechanism of imatinib resistance in GISTs involves missense mutation in the kinase domain of KIT, including Thr670Ile, Tyr823Asp, and Val654Ala. The established mechanisms and potential mechanisms of imatinib resistance in GISTs, the imaging studies indicative of early development of imatinib resistance, and the management of imatinib-resistant GISTs are discussed.
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PMID:Imatinib resistance in gastrointestinal stromal tumors. 1594 89

Oncogenic mutations of the receptor tyrosine kinase KIT are encountered in myeloid leukemia and various solid tumors, including gastrointestinal stromal tumors. We previously identified the human oncogenic germ line mutant KIT(K642E), a substitution in the tyrosine kinase 1 domain (TK1D) in a familial form of gastrointestinal stromal tumors. The effects of oncogenic KIT mutants on cell signaling and regulation are complex. Cellular models are valuable basic tools to tailor novel strategies on specific cellular and molecular bases for tumors expressing KIT oncogenic mutants. Murine KIT(WT) and the murine homologues of human KIT oncogenic mutants, further referred to as KIT(K641E) and KIT(del559), a point deletion in the juxtamembrane domain (JMD), were stably expressed in IL-3-dependent Ba/F3 cells. Major differences in the constitutively activation of Akt/PKB, MAP kinases and STATs pathways were observed between KIT(K641E) and KIT(del559), whereas KIT ligand elicited responses in both mutants. Noteworthy, the protein level of the phosphoinositide phosphatase SHIP1, but not SHIP2 and PTEN, was reduced in KIT(K641E) only while inhibition of KIT phosphorylation reversibly raised SHIP1 level in both JMD and TK1D oncogenic mutants, unraveling the control of SHIP protein level by KIT phosphorylation.
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PMID:Differences in signaling pathways and expression level of the phosphoinositide phosphatase SHIP1 between two oncogenic mutants of the receptor tyrosine kinase KIT. 1599 Feb 78

Oncogenic conversion of receptor protein tyrosine kinases (RTK) is a frequent feature of malignant cells. This knowledge has fostered efforts to develop target-specific low molecular weight therapeutics able to obstruct RTK signalling. The clinical efficacy of the ABL- and KIT-inhibitors are paradigmatic of the power of this approach. Here, we focus on small-molecule inhibitors for RTKs involved in human cancer. In particular, we examine the KIT, MET and RET receptors that are targeted by genetic alterations in both sporadic and familial human tumours.
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PMID:Receptor tyrosine kinases as targets for anticancer therapeutics. 1602 46


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