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)

The aberrant activation of tyrosine kinases represents an important oncogenic mechanism, and yet the majority of such events remain undiscovered. Here we describe a bead-based method for detecting phosphorylation of both wild-type and mutant tyrosine kinases in a multiplexed, high-throughput and low-cost manner. With the aim of establishing a tyrosine kinase-activation catalog, we used this method to profile 130 human cancer lines. Follow-up experiments on the finding that SRC is frequently phosphorylated in glioblastoma cell lines showed that SRC is also activated in primary glioblastoma patient samples and that the SRC inhibitor dasatinib (Sprycel) inhibits viability and cell migration in vitro and tumor growth in vivo. Testing of dasatinib-resistant tyrosine kinase alleles confirmed that SRC is indeed the relevant target of dasatinib, which inhibits many tyrosine kinases. These studies establish the feasibility of tyrosine kinome-wide phosphorylation profiling and point to SRC as a possible therapeutic target in glioblastoma.
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PMID:Bead-based profiling of tyrosine kinase phosphorylation identifies SRC as a potential target for glioblastoma therapy. 1909 99

Tyrosine kinases (TKs) are attractive targets for cancer therapy, as quite often their abnormal signaling has been linked with tumor development and growth. Constitutive activated TKs stimulate multiple signaling pathways responsible for DNA repair, apoptosis, and cell proliferation. During the last few years, thorough analysis of the mechanism underlying tyrosine kinase's activity led to novel cancer therapy using TKs blockers. These drugs are remarkably effective in the treatment of various human tumors including head and neck, gastric, prostate and breast cancer and leukemias. The most successful example of kinase blockers is Imatinib (Imatinib mesylate, Gleevec, STI571), the inhibitor of Bcr/Abl oncoprotein, which has become a first-line therapy for chronic myelogenous leukemia. The introduction of STI571 for the treatment of leukemia in clinical oncology has had a dramatic impact on how this disease is currently managed. Others kinase inhibitors used recently in cancer therapy include Dasatinib (BMS-354825) specific for ABL non-receptor cytoplasmic kinase, Gefitinib (Iressa), Erlotinib (OSI-774, Tarceva) and Sunitinib (SU 11248, Sutent) specific for VEGF receptor kinase, AMN107 (Nilotinib) and INNO-406 (NS-187) specific for c-KIT kinase. The following TK blockers for treatment of various human tumors are in clinical development: Lapatinib (Lapatinib ditosylate, Tykerb, GW-572016), Canertinib (CI-1033), Zactima (ZD6474), Vatalanib (PTK787/ZK 222584), Sorafenib (Bay 43-9006, Nexavar), and Leflunomide (SU101, Arava). Herein, we discuss the chemistry, biological activity and clinical potential of new drugs with tyrosine kinase blockers for cancer treatment.
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PMID:Tyrosine kinase blockers: new hope for successful cancer therapy. 1914 83

Glioblastoma is defined by its aggressive invasion, microvascular proliferation, and central necrosis. BMS-354825 (dasatinib) is an ATP-competitive small-molecule inhibitor effective in treating drug-resistant tumors with mutant BCR-ABL, KIT, and epidermal growth factor receptor by blocking tyrosine phosphorylation sites that are critical in tumorigenesis. In studying the action of dasatinib in human glioblastoma, we found that levels of phospho-SRC, AKT, and ribosomal protein S6 were decreased in cell lines treated with low nanomolar concentrations of dasatinib at baseline and following stimulation with epidermal growth factor. Furthermore, an increased sensitivity to dasatinib was noted in glioma cells with functional PTEN. Reduction of invasive potential was observed in vitro at concentrations well below the IC(50) of dasatinib, which was corroborated by immunofluorescence staining showing disruption of paxillin localization to focal adhesions and decreases in focal adhesion kinase autophosphorylation. Cell cycle analysis revealed minimal G(1) arrest but a significant increase in autophagic cell death in glioma cells treated with dasatinib as assessed by acridine orange staining and a concomitant increase in light chain 3 expression and processing. Combination treatment of glioma cells with dasatinib and temozolomide resulted in a significant increase in cell cycle disruption and autophagic cell death. Dasatinib in combination with temozolomide more effectively increased the therapeutic efficacy of temozolomide than when dasatinib was combined with carboplatin or irinotecan. These results strongly support the clinical use of dasatinib in the treatment of glioblastoma and provide a rationale for combination therapy with dasatinib and temozolomide.
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PMID:Dasatinib-induced autophagy is enhanced in combination with temozolomide in glioma. 1919 Jan 19

Resistance to imatinib in patients with chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) has emerged as a significant clinical issue. Dasatinib is a tyrosine kinase inhibitor that has 325-fold greater in vitro activity against native BCR-ABL (breakpoint cluster region-Abelson leukemia virus) compared with imatinib and can overcome primary (intrinsic) and secondary (acquired) imatinib resistance. Here, we review the clinical profile of dasatinib in imatinib-resistant and -intolerant patients and share clinical approaches for managing adverse events (AEs) to ensure maximum patient benefit. References were obtained through literature searches on PubMed as well as from the Proceedings of Annual Meetings of the American Society of Clinical Oncology, the American Society of Hematology, and European Hematology Association. Phase II and III studies of dasatinib in patients with imatinib-resistant or -intolerant CML in any phase or Ph+ ALL were selected for discussion. Dasatinib is currently indicated for the treatment of patients with imatinib-resistant or -intolerant CML or Ph+ ALL. AEs associated with dasatinib are typically mild to moderate, and are usually resolved with temporary treatment interruption and/or dose adjustments. A Phase III dose optimization study showed that in patients with chronic phase (CP) CML, 100 mg once-daily dasatinib improves the safety profile, particularly pleural effusion and thrombocytopenia, while maintaining efficacy compared with the previously recommended dose of 70 mg twice-daily. Dasatinib has a manageable safety profile. For patients with CP CML, a new recommended starting dose of 100 mg once daily has recently been approved. The recommended dose for patients with advanced CML or Ph+ ALL remains 70 mg twice daily.
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PMID:New dosing schedules of dasatinib for CML and adverse event management. 1923 16

Dasatinib, a tyrosine kinase inhibitor of BCR-ABL, was originally approved for the second-line treatment of any-phase chronic myelogenous leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia at a dosage of 70 mg twice daily. In chronic-phase (CP) CML resistant to first-line imatinib, this regimen is more efficacious than high-dose imatinib. A Phase III study of CP CML has now shown that dasatinib 100 mg once daily is therapeutically noninferior to 70 mg twice daily and has an improved safety profile. Patients receiving dasatinib 100 mg once daily suffered significantly fewer thrombocytopenia (grade 3-4) and pleural effusion (all grades) events than those receiving dasatinib 70 mg twice daily. Fewer patients receiving dasatinib 100 mg once daily also required dose interruption/reduction or discontinuation. The recommended regimen for dasatinib in patients with CP disease and who are resistant or intolerant to primary therapy with imatinib is now 100 mg once daily.
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PMID:New approved dasatinib regimen available for clinical use. 1927 7

Dasatinib was approved in 2006 for the treatment of imatinib-resistant chronic myelogenous leukemia and functions primarily through the inhibition of BCR-ABL and Src kinase. Dasatinib is extensively metabolized in humans by CYP3A4. In this study, we report that the bioactivation of dasatinib by CYP3A4 proceeds through a reactive intermediate that leads to CYP3A4 inactivation with K(I) = 6.3 microM and k(inact) = 0.034 min(-1). The major mechanism of inactivation proceeds through hydroxylation at the para-position of the 2-chloro-6-methylphenyl ring followed by further oxidation, forming a reactive quinone-imine, similar to the reactive intermediates formed by acetaminophen and diclofenac. Formation of a reactive imine-methide was also detected but appears to be a minor pathway. When glutathione was added to human liver microsomal incubations, dasatinib-glutathione adducts were detected. Numerous dasatinib analogs were synthesized in an effort to understand what modifications would block the formation of reactive intermediates during dasatinib metabolism. It is interesting to note that blocking the site of hydroxylation with a methyl group was not effective because a reactive imine-methide was formed, nor was blocking the site with fluorine because the fluorine was removed through an oxidative defluorination mechanism and the reactive quinone-imine was still formed. Numerous analogs are presented that did effectively block the formation of glutathione adducts and prevent the inactivation of CYP3A4.
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PMID:Characterization of dasatinib and its structural analogs as CYP3A4 mechanism-based inactivators and the proposed bioactivation pathways. 1928 95

Dasatinib, a broad-spectrum tyrosine kinase inhibitor (TKI), predominantly targets BCR-ABL and SRC oncoproteins and also inhibits off-target kinases, which may result in unexpected drug responses. We identified 22 patients with marked lymphoproliferation in blood while on dasatinib therapy. Clonality and immunophenotype were analyzed and related clinical information was collected. An abrupt lymphocytosis (peak count range 4-20 x 10(9)/l) with large granular lymphocyte (LGL) morphology was observed after a median of 3 months from the start of therapy and it persisted throughout the therapy. Fifteen patients had a cytotoxic T-cell and seven patients had an NK-cell phenotype. All T-cell expansions were clonal. Adverse effects, such as colitis and pleuritis, were common (18 of 22 patients) and were preceded by LGL lymphocytosis. Accumulation of identical cytotoxic T cells was also detected in pleural effusion and colon biopsy samples. Responses to dasatinib were good and included complete, unexpectedly long-lasting remissions in patients with advanced leukemia. In a phase II clinical study on 46 Philadelphia chromosome-positive acute lymphoblastic leukemia, patients with lymphocytosis had superior survival compared with patients without lymphocytosis. By inhibiting immunoregulatory kinases, dasatinib may induce a reversible state of aberrant immune reactivity associated with good clinical responses and a distinct adverse effect profile.
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PMID:Clonal expansion of T/NK-cells during tyrosine kinase inhibitor dasatinib therapy. 2765 75

Src family kinases (SFKs) are commonly deregulated in cancer cells. Among other functions, SFKs are critical for cellular migration and invasion. SFK inhibitors are being studied as targeted cancer drugs, but there are no biomarkers for noninvasive assessment of SFK inhibition. The aim of this study was to evaluate whether imaging of alpha(V)beta(3) integrin activity with positron emission tomography (PET) and [(64)Cu]DOTA-cyclo-(Arg-Gly-Asp-dPhe-Lys) {[(64)Cu]DOTA-c(RGDfK)} can be used for monitoring response to the SFK inhibitor dasatinib. Severe combined immunodeficient mice bearing U87MG xenografts were gavaged daily over 72 hours with 72 or 95 mg/kg of dasatinib or vehicle. Tumor uptake of [(64)Cu]DOTA-c(RGDfK) was measured by small-animal PET. In parallel, fluorodeoxyglucose (FDG) scans were performed to assess tumor metabolism in response to dasatinib treatment. Dasatinib significantly (P<0.0001) reduced [(64)Cu]DOTA-c(RGDfK) uptake by up to 59% in U87MG xenografts [2.10+/-0.14% injected dose/gram (ID/g) in the 95 mg/kg group and 3.12+/-0.18% ID/g in the 72 mg/kg group, versus 5.08+/-0.80% ID/g in controls]. In contrast, tumor FDG uptake showed no significant reduction with dasatinib therapy (8.13+/-0.45% ID/g in treated versus 10.39+/-1.04% ID/g in controls; P=0.170). Histologically, tumors were viable at the time of the follow-up PET scan but showed inhibition of focal adhesion kinase. Continued dasatinib treatment resulted in a significant inhibition of tumor growth (tumor size on day 10 of therapy: 21.13+/-2.60 mm(2) in treated animals versus 122.50+/-17.68 mm(2) in controls; P=0.001). [(64)Cu]DOTA-c(RGDfK) may provide a sensitive means of monitoring tumor response to SFK inhibition in alpha(V)beta(3)-expressing cancers early in the course of therapy.
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PMID:Noninvasive imaging of alphaVbeta3 function as a predictor of the antimigratory and antiproliferative effects of dasatinib. 1931 69

Dasatinib is the most potent BCR-ABL inhibitor, with 325-fold higher potency than imatinib against unmutated BCR-ABL in vitro. Studies have demonstrated the benefits of dasatinib 70 mg twice daily in patients with accelerated-phase chronic myeloid leukemia intolerant or resistant to imatinib. A phase 3 study compared the efficacy and safety of dasatinib 140 mg once daily with the current twice-daily regimen. Here, results from the subgroup with accelerated-phase chronic myeloid leukemia (n = 317) with a median follow-up of 15 months (treatment duration, 0.03-31.15 months) are reported. Among patients randomized to once-daily (n = 158) or twice-daily (n = 159) treatment, rates of major hematologic and cytogenetic responses were comparable (major hematologic response, 66% vs 68%; major cytogenetic response, 39% vs 43%, respectively). Estimated progression-free survival rates at 24 months were 51% and 55%, whereas overall survival rates were 63% versus 72%. Once-daily treatment was associated with an improved safety profile. In particular, significantly fewer patients in the once-daily group experienced a pleural effusion (all grades, 20% vs 39% P < .001). These results demonstrate that dasatinib 140 mg once daily has similar efficacy to dasatinib 70 mg twice daily but with an improved safety profile. This trial is registered at www.clinicaltrials.gov as #CA180-035.
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PMID:Phase 3 study of dasatinib 140 mg once daily versus 70 mg twice daily in patients with chronic myeloid leukemia in accelerated phase resistant or intolerant to imatinib: 15-month median follow-up. 1994 22

Dasatinib is a tyrosine kinase inhibitor (including BCR-ABL and the SRC family) that is effective in patients with chronic myeloid leukemia. Dasatinib has pH-dependent solubility and is bioavailable as an oral formulation. The effect of gastric pH modifiers on dasatinib pharmacokinetics is evaluated in an open-label, randomized, 3-period, 3-treatment crossover study. Twenty-four healthy subjects receive treatment A (2 doses of dasatinib 50 mg separated by 12 hours), treatment B (famotidine 40 mg given 2 hours after dasatinib 50 mg and 10 hours before another dose of dasatinib 50 mg), and treatment C (30 mL of an antacid containing aluminum/magnesium hydroxides given 2 hours before dasatinib 50 mg and concomitantly with dasatinib 50 mg 12 hours after the previous dasatinib dose); a 7-day washout separates each treatment period. When famotidine is administered 2 hours after dasatinib, dasatinib exposure is similar to dasatinib administered alone. However, dasatinib exposure is reduced by approximately 60% when famotidine is administered 10 hours before dasatinib dosing. In contrast, dasatinib exposure is unchanged when antacid (Maalox) is administered 2 hours before dasatinib; but when the antacid is coadministered with dasatinib, dasatinib exposure is reduced by approximately 55% to 58%. This indicates that H(2)-receptor antagonists should not be coadministered with dasatinib. Dasatinib may be administered with acid-neutralizing antacids if the doses are temporally separated by at least 2 hours.
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PMID:Phase I study of the effect of gastric acid pH modulators on the bioavailability of oral dasatinib in healthy subjects. 1939 85


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