Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:2.7.10.2 (focal adhesion kinase)
 44,029 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Protein kinases have emerged as one of the most promising targets for rational drug discovery. In a similar manner to imatinib mesylate (Gleevec), hematological malignancies offer multiple pharmacologic opportunities for manipulation of kinase-induced tumor cell proliferation. Certain kinases have been validated as targets for drug discovery in hematological malignancies (such as BCR-ABL and FLT3); other novel kinases hold considerable interest for targeted intervention: myeloid leukemias (KDR, KIT, CSF-1R, RAS and RAF), lymphoid leukemias (JAK2 fusion protein, TIE-1, CDK modulators), lymphoma (ALK, CDK modulators, mTOR), myeloproliferative disorders (PDGF-R or FGF-R fusion gene products, FGF-R1) and myeloma (FGF-R3, STAT3). Over the past five years, the number of kinase-targeted drug therapies undergoing clinical development has increased exponentially. This review will focus on novel kinase targets currently undergoing preclinical and clinical investigation.
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PMID:Kinases as drug discovery targets in hematologic malignancies. 1630 89

Ribosomal protein S6 kinase (S6K) is activated by an array of mitogenic stimuli and is a key player in the regulation of cell growth. The activation process of S6 kinase involves a complex and sequential series of multiple Ser/Thr phosphorylations and is mainly mediated via phosphatidylinositol 3-kinase (PI3K)-3-phosphoinositide-dependent protein kinase-1 (PDK1) and mTor-dependent pathways. Upstream regulators of S6K, such as PDK1 and protein kinase B (PKB/Akt), are recruited to the membrane via their pleckstrin homology (PH) or protein-protein interaction domains. However, the mechanism of integration of S6K into a multi-enzyme complex around activated receptor tyrosine kinases is not clear. In the present study, we describe a specific interaction between S6K with receptor tyrosine kinases, such as platelet-derived growth factor receptor (PDGFR). The interaction with PDGFR is mediated via the kinase or the kinase extension domain of S6K. Complex formation is inducible by growth factors and leads to S6K tyrosine phosphorylation. Using PDGFR mutants, we have shown that the phosphorylation is exerted via a PDGFR-src pathway. Furthermore, src kinase phosphorylates and coimmunoprecipitates with S6K in vivo. Inhibitors towards tyrosine kinases, such as genistein and PP1, or src-specific SU6656, but not PI3K and mTor inhibitors, lead to a reduction in tyrosine phosphorylation of S6K. In addition, we mapped the sites of tyrosine phosphorylation in S6K1 and S6K2 to Y39 and Y45, respectively. Mutational and immunofluorescent analysis indicated that phosphorylation of S6Ks at these sites does not affect their activity or subcellular localization. Our data indicate that S6 kinase is recruited into a complex with RTKs and src and becomes phosphorylated on tyrosine/s in response to PDGF or serum.
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PMID:Receptor association and tyrosine phosphorylation of S6 kinases. 1664 May 65

Imatinib mesylate (IM), a small molecule that is a selective inhibitor of the ABL, platelet derived growth factor receptor (PDGFR-R) and stem cell ligand receptor (c-kit) tyrosine kinases (TK). IM was also found to inhibit the TK activity of BCR/ABL fusion protein produced in chronic myelogenous leukemia, with marked clinical activity against the disease. Since both PDGF-R and c-kit both having a putative role in tumorigenesis, we investigated the efficacy and safety of the use of IM in patients with endocrine tumors unresponsive to conventional therapies that expressed c-kit and/or PDGF-R (within the framework of a comprehensive phase II multi-center study of IM in patients with solid tumors). IM was initiated at a dose of 400 mg/day, with possible dose escalation within 1 week to 600 mg/day and an option to raise the dose to 800 mg/day in the event of progression and in the absence of safety concerns for a period of up to 12 months. Between September 2002 and July 2003, 15 adult patients with disseminated endocrine tumors were recruited as follows: medullary thyroid carcinoma (MTC, n = 6); adrenocortical carcinoma (ACC, n = 4); malignant pheochromocytoma (pheo, n = 2); carcinoid (non-secreting, n = 2), neuroendocrine tumor (NET, n = 1). No objective responses were observed. MTC--disease progression in 4 patients, and treatment discontinuation in 2 patients due to adverse events; ACC--disease progression in 3 patients, and treatment discontinuation in 1 patient due to severe psychiatric adverse event; Pheo--disease progression in 2 patients; Carcinoid--stable disease in 1 patient (6.5 months), and disease progression in 1 patient; NET--disease progression in 1 patient. IM does not appear to be useful for treatment of malignant endocrine tumors, also causing significant toxicity in this patient population.
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PMID:The role of imatinib mesylate (Glivec) for treatment of patients with malignant endocrine tumors positive for c-kit or PDGF-R. 1672 80

Imatinib mesylate (IM), is a selective and competitive inhibitor of tyrosine kinases, including BCR-ABL, ABL, KIT, and the platelet-derived growth factor receptors (PDGF-R). It binds to the ATP-binding site of the target kinase and prevents the transfer of phosphate from ATP to the tyrosine residues of various substrates. At oral doses of 200-600 mg, the majority of patients with chronic myeloid leukaemia, Philadelphia chromosome-positive acute lymphoblastic leukemia expressing the BCR-ABL fusion protein and gastrointestinal stromal tumours (GIST) achieve a bio-molecular and clinical response, frequently complete, associated with limited toxicity. Several other human cancers, as small-cell lung carcinoma, melanoma, seminoma, some sarcomas, and adenoid cystic carcinomas may over-express KIT or PDGF-R, and clinical trials to evaluate the role of IM in the treatment of such cancers are currently ongoing. We determined c-KIT with Dako CD 117 antibody in 5 cases of advanced ocular melanoma (OM) and we found positive immuno-reactivity for CD 117 in three patients. We treated all patients with palliative-use IM at the oral dose of 400 mgr daily. We obtained in expressing positive immuno-reactivity for CD 117 patients: a reduction of malignant ascites in one, a partial remission in the neck nodes in another, and progression of liver metastases in the third. Evidences of progression has been reported in the other two patients expressing negative immuno-reactivity for CD 117. We conclude that the effect of IM should be assessed only in OM with positive immuno-histochemical c-kit (CD 117) expression. IM might be a potential therapeutic strategy for these patients.
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PMID:Tyrosine kinase inhibitor imatinib mesylate as anticancer agent for advanced ocular melanoma expressing immunoistochemical C-KIT (CD 117): preliminary results of a compassionate use clinical trial. 1676

The renin-angiotensin system is a central component of the physiological and pathological responses of cardiovascular system. Its primary effector hormone, angiotensin II (ANG II), not only mediates immediate physiological effects of vasoconstriction and blood pressure regulation, but is also implicated in inflammation, endothelial dysfunction, atherosclerosis, hypertension, and congestive heart failure. The myriad effects of ANG II depend on time (acute vs. chronic) and on the cells/tissues upon which it acts. In addition to inducing G protein- and non-G protein-related signaling pathways, ANG II, via AT(1) receptors, carries out its functions via MAP kinases (ERK 1/2, JNK, p38MAPK), receptor tyrosine kinases [PDGF, EGFR, insulin receptor], and nonreceptor tyrosine kinases [Src, JAK/STAT, focal adhesion kinase (FAK)]. AT(1)R-mediated NAD(P)H oxidase activation leads to generation of reactive oxygen species, widely implicated in vascular inflammation and fibrosis. ANG II also promotes the association of scaffolding proteins, such as paxillin, talin, and p130Cas, leading to focal adhesion and extracellular matrix formation. These signaling cascades lead to contraction, smooth muscle cell growth, hypertrophy, and cell migration, events that contribute to normal vascular function, and to disease progression. This review focuses on the structure and function of AT(1) receptors and the major signaling mechanisms by which angiotensin influences cardiovascular physiology and pathology.
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PMID:Angiotensin II cell signaling: physiological and pathological effects in the cardiovascular system. 1687 Aug 27

Imatinib (Gleevec/STI-571/CGP57148B, Novartis) is a small-molecule, tyrosine kinase inhibitor developed to target BCR-ABL, c-Kit, and PDGF-R. Through inhibition of these oncogenic kinases, imatinib is effective in the treatment of BCR-ABL-positive leukemia, gastrointestinal stromal tumor, and hypereosinophilic syndrome, respectively. However, clinical success of imatinib is hampered by acquired resistance that may occur through several mechanisms including kinase domain mutation, target amplification, and activation of alternate signaling pathways. Strategies to overcome resistance have included targeting BCR-ABL stability and downstream signaling pathways important for tumor growth. Additional work has shown that new BCR-ABL kinase inhibitors with increased potency or alternate conformation-binding properties can target imatinib resistance. This review focuses on the mechanisms of imatinib resistance and the strategies currently being developed to overcome clinical resistance.
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PMID:Treating imatinib-resistant leukemia: the next generation targeted therapies. 1690 25

Recent studies in Cdc42 knockout mouse embryonic stem (ES) cells and ES-derived fibroblastoid cell lines raise concern on a body of literature derived by dominant mutant expression approach in a variety of cell lines implicating mammalian Cdc42 as a key regulator of filopodia induction, directional migration and cell cycle progression. To resolve the physiological function of mammalian Cdc42, we have characterized the Cdc42(-/-) and Cdc42GAP(-/-) primary mouse embryonic fibroblasts (MEFs) produced by gene targeting as the Cdc42 loss- or gain-of-activity cell model. The Cdc42(-/-) cells were defective in filopodia formation stimulated by bradykinin and in dorsal membrane ruffling stimulated by PDGF, whereas the Cdc42GAP(-/-) cells displayed spontaneous filopodia. The Cdc42 loss- or gain-of-activity cells were defective in adhesion to fibronectin, wound-healing, polarity establishment, and migration toward a serum gradient. These defects were associated with deficiencies of PAK1, GSK3beta, myosin light chain, and FAK phosphorylation. Furthermore, Cdc42(-/-) cells were defective in G1/S-phase transition and survival, correlating with deficient NF-kappaB transcription and defective JNK, p70 S6K, and ERK1/2 activation. These results demonstrate a different requirement of Cdc42 activity in primary MEFs from ES or ES-derived clonal fibroblastoid cells and suggest that Cdc42 plays cell-type-specific signaling roles.
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PMID:Gene targeting of Cdc42 and Cdc42GAP affirms the critical involvement of Cdc42 in filopodia induction, directed migration, and proliferation in primary mouse embryonic fibroblasts. 1691 16

STI571 (imatinib; Gleevec) was developed as the first molecularly targeted therapy. It was the result of an extensive search for molecules to block the aberrant activity of Abl kinase in the fusion protein Bcr-Abl. In addition, it can specifically inhibit the activity of c-Kit and PDGF receptors. This orally bioavailable drug has a low toxicity profile. It is approved to treat the patients with chronic myelogenous leukemia (CML) or gastrointestinal stromal tumor (GIST). It produces hematological, cytogenetic, and molecular remission with significant efficacy, particularly in patients with chronic-phase CML. However, there is well-documented proof of primary and secondary resistance to STI571 with progression of leukemia. More evidence indicates that this single drug may not be sufficient to completely eradicate BCR-ABL-positive stem cells. A variety of strategies has already been developed to improve the effectiveness of CML treatment, including targeting the expression or stability of the Bcr-Abl kinase itself, targeting signaling pathways activated by this kinase, as well as designing novel Abl inhibitors. In this review the molecular mechanisms of STI571 action, its effectivenes against CML, GIST, and melanoma, as well as new approaches to improve its efficacy, mainly by overcoming STI571 resistance, are discussed.
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PMID:[STI571: a summary of targeted therapy]. 1724 18

Gastrointestinal stromal tumors GIST are rare mesenchymal tumors of the gastrointestinal tract characterized by expression of a receptor that activates tyrosine kinase called C- kit. Since malignant GIST has an extremely poor prognosis even after surgical resection. The developement of a tyrosine kinase inhibitor, STI571/imatinib mesylate/Gleevec, Glivec 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 metastaic disease. We report a 32 year old male patient with subcardiale gastric GIST and massive gastrointestinale bleeding. The patient underwent total gastrectomy, D2 lymphadenestomy, distal pancreatectomy and splenectomy on 02.02. 2004. Histopathology examination of the primary tumor revealed a strong C-Kit expression and CD 34 +++, Ki67 20 and so called "Pure GIST" was approved Liver metastasis was detected on ultrasound and CT 12 months later and segmentectomy S7 was performed on 23.03.2005. Postoperative course was uneventfull. HP examination--malignant 35 x 30 mm sarcoma like tumor of mesenchymal origin. The patient received adjuvant imatinib-mesylate Gleevec Novartis Pharma Basel 400 mg a day. The initial complete response to treatment continued to 24 monts postoperatively Imatinib is a recent and very promising tretemenextirpation remains the only curative treatment of malignant GIST as evideneced by our patient.
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PMID:[Gastrointestinal gastric tumor (GIST) as a cause of massive hemorrhage from the upper digestive tract]. 1763 80

Imatinib mesilate, which efficiently inhibits BCR-ABL,and KIT as well as platelet-derived growth factor receptor (PDGF-R) kinases, is highly effective for clinical treatment of CML, Ph+ALL, and advanced GIST with good tolerability, respectively. Acquired resistance to the drug,however, becomes an clinically emerging problem with long-standing use. Meanwhile, sunitinib malate,which inhibits three VEGF-Rs and FLT 3 in addition to KIT as well as PDGF-R, was clinically evaluated in the phase II clinical trials for imatinib-resistant or intolerant GIST, and advanced renal cell carcinoma in Japan. Sunitinib is therapeutically effective for both on imatinib-resistant GIST and advanced renal cell carcinoma with modest tolerability, and is now under review for approval in Japan.
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PMID:[Imatinib . Sunitinib]. 1768 1


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