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)

Imatinib mesylate, also known as STI571 or CGP57148, is a competitive inhibitor of a few 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 300 mg or greater, the vast majority of patients with chronic myeloid leukaemia achieve a haematological response and this is usually associated with limited toxicity. Imatinib also has substantial activity in Philadelphia chromosome-positive acute lymphoblastic leukaemia expressing the BCR-ABL fusion protein. Gastrointestinal stromal tumours (GISTs) have also been evaluated for clinical activity of imatinib. About 90% of malignant GISTs harbour a mutation in c-kit leading to KIT receptor autophosphorylation and ligand-independent activation. According to initial clinical studies, more than 50% of GISTs respond to therapy within a few months, and only about 10-15% progress. The potential for cure and the optimal length of treatment are currently not known. Several other human cancers may over-express KIT or PDGF-R, and clinical trials to evaluate the role of imatinib in the treatment of such cancers are currently ongoing. Imatinib is an example of a specifically designed, highly targeted cancer therapy, which poses novel requirements for both pathology laboratories and clinicians in terms of identifying the major molecular mechanisms involved in tumour growth.
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PMID:Tyrosine kinase inhibitor imatinib (STI571) as an anticancer agent for solid tumours. 1168 Jul 92

The deregulated tyrosine kinase activity of the BCR-ABL fusion protein has been established as the causative molecular event in chronic myelogenous leukaemia. Thus, the BCR-ABL tyrosine kinase is an ideal target for pharmacological inhibition. STI571 (formerly CGP57148B), is an ABL-specific inhibitor of tyrosine kinase that, in preclinical studies, selectively killed BCR-ABL-containing cells in vitro and in vivo. Clinical studies have shown the potential of this specifically targeted therapy, and STI571 is emerging as an important new therapeutic agent for chronic myelogenous leukaemia.
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PMID:STI571: an inhibitor of the BCR-ABL tyrosine kinase for the treatment of chronic myelogenous leukaemia. 1190 36

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal neoplasm of the gastrointestinal tract. Until recently, surgery has been the only effective therapy for GIST. However, even after complete resection of tumor, many patients still eventually die of disease recurrence. Conventional chemotherapy and radiation therapy have been of limited value. Within the last few years, it was discovered that most GISTs have a gain-of-function mutation in the c-kit proto-oncogene. This results in ligand-independent activation of the KIT receptor tyrosine kinase and an unopposed stimulus for cell growth. STI-571 is a small molecule that selectively inhibits the enzymatic activity of the ABL, platelet-derived growth factor receptor, and KIT tyrosine kinases and the BCR-ABL fusion protein and is a landmark development in cancer therapy. Its clinical development marks a new era of rational and targeted molecular inhibition of cancer that emanates from direct collaborations between scientists and clinicians. It provides proof of the principle that a specific molecular inhibitor can drastically and selectively alter the survival of a neoplastic cell with a particular genetic aberration. The advent of STI-571 has markedly altered the clinical approach to GIST. It has proven to be effective in metastatic GIST and is also under investigation as a neoadjuvant and adjuvant therapy.
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PMID:Clinical management of gastrointestinal stromal tumors: before and after STI-571. 1209 71

BCR-ABL fusion oncogene is the molecular hallmark of chronic myelogenous leukemia (CML), a condition characterized by a progression from a chronic to acute phase leukemia because of secondary genetic events, the nature of which remains largely unknown. Here, we report that the expression of the p210 BCR-ABL fusion protein leads to a down-regulation of BRCA1 protein, a gene product involved in the maintenance of genome integrity. BRCA1 protein is nearly undetectable in leukemia cells from patients with CML, both during the chronic phase and in blast crisis. Similarly, stable transfection-enforced expression of p210 protein in established hematopoietic cell lines leads to severe BRCA1 depletion. The lack of significant change in BRCA1 mRNA level in cells expressing p210 supports the hypothesis that the regulation of BRCA1 protein level occurs after transcription. It is abolished on exposure of the cells to STI571 and by mutation in the adenosine triphosphate (ATP) pocket of p210 and thus seems to require the tyrosine kinase activity of BCR-ABL. Cell lines expressing high levels of BCR-ABL display an increased rate of sister chromatid exchange and chromosome aberrations after ionizing radiation. These findings reveal a novel link between the oncoprotein BCR-ABL and the tumor-suppressor protein BRCA1.
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PMID:Down-regulation of BRCA1 in BCR-ABL-expressing hematopoietic cells. 1257 38

The BCR-ABL oncogene is generated by the Philadelphia chromosome (Ph) translocation, fusing the BCR gene to the ABL gene. The BCR-ABL fusion protein has elevated ABL tyrosine kinase activity that is critical for transformation of hematopoietic cells. Chronic myelogenous leukemia (CML) cells transformed by BCR-ABL show reduced growth factor requirements and apoptosis, as well as enhanced viability and altered adhesion. The elevated ABL kinase activity leads to chronic activation of signaling pathways that are required for all aspects of transformation. Progression of the disease from chronic phase to blast crisis correlates with additional cytogenetic alterations that are likely to contribute to the failure of traditional therapy. This review describes molecular mechanisms that are thought to be important for transformation by the BCR-ABL oncoprotein and points at pathways for targeted drug development in the treatment of CML.
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PMID:Molecular mechanisms of transformation by the BCR-ABL oncogene. 1278 68

Molecular targeting therapies for hematological malignant diseases such as monoclonal antibodies and small molecules have been reviewed. Imatinib mesylate (STI571) targets the tyrosine kinase activity of the BCR-ABL fusion protein in CML, and was superior to IFN-alpha plus low-dose cytarabine in newly diagnosed chronic-phase CML in a phase III randomized study. Imatinib induced apoptosis in BCR-ABL-positive cells in vitro, and activates several signaling pathways such as PI3K/Akt, STAT5 and Ras/MAPK. Combination therapies with imatinib and new strategies for downregulation of intracellular BCR-ABL protein levels have also been investigated from the phenomenon of resistance to imatinib. Anti-CD20 (rituximab) became the first monoclonal antibody approved for the treatment of a relapsed/refractory follicular/low-grade NHL and promising results were obtained from a phase III randomized study. Although antibody-dependent cell-mediated cytotoxicity and complement-mediated cytotoxicity are likely to be the major effectors of B-cell depletion in vivo, direct cytotoxicity by CD20 monoclonal antibody on B-cell lines in vitro has been reported. Anti-CD33 (Mylotarg) and FLT3 inhibitors for AML have also been used in clinical trials and signaling pathways induced by these agents are under intensive investigation. Arsenic trioxide, like all-TRANS-retinoic acid (ATRA), downregulates promyelocytic leukemia protein/retinoic acid receptor-alpha (PML/RARalpha) fusion protein and induced apoptosis in APL cells, and promising results were obtained from ATRA-resistant APL patients. Finally we show our promising in vitro and in vivo data of R-etodolac (a non-steroidal anti-inflammatory drug lacking cyclooxygenase inhibitor activity) against chronic lymphocytic leukemia (CLL) cells.
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PMID:Apoptosis induced by molecular targeting therapy in hematological malignancies. 1464 49

Chronic myeloid leukemia (CML) is characterized by a 9:22 translocation resulting in production of a chimeric BCR-ABL fusion protein that has constitutive tyrosine kinase activity and drives leukemic transformation. Imatinib mesylate, a selective inhibitor of BCR-ABL, has been introduced into clinical trials with favorable toxicity and impressive activity at all disease stages. In a phase III study of diagnosed chronic phase CML, imatinib mesylate was superior to interferon plus cytarabine in cytogenetic response, freedom from disease progression, and tolerability. Hematopoietic stem cell transplantation remains the only established cure for CML. Recent reports show continued improvements with survivals after matched sibling grafts greater than 80% at 3 to 5 years. Therefore, recent advances in conventional and transplant therapy have improved treatment options for newly diagnosed patients. Sensitive and specific monitoring techniques developed for CML may help further refine treatment with regard to using these and other emerging therapies.
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PMID:Treatment options for newly diagnosed patients with chronic myeloid leukemia. 1469 51

Imatinib mesylate and rituximab are molecularly targeted drugs against the BCR-ABL fusion protein and the CD20 antigen, respectively. Although these drugs have excellent anticancer effects, a major concern is drug resistance. We have investigated the case of a patient with Philadelphia chromosome-positive and CD20+ acute lymphocytic leukemia who acquired resistance to imatinib and rituximab. Imatinib therapy resulted in prompt cytogenetic remission, but resistance developed shortly thereafter. Sequencing of the kinase domain of the ABL gene and allele-specific polymerase chain reaction analysis revealed a point mutation resulting in an E255V substitution that was present before the therapy. After the patient received mild chemotherapy followed by rituximab administration, hematologic and cytogenetic remission was sustained for 5.5 months. The recurrent leukemic cells after the rituximab therapy showed not only the E255V mutation in the ABL gene but also loss of the CD20 antigen due to impaired transcription of the CD20 gene. The results of 2-color flow cytometry analysis showed that a small population of CD20(-) leukemic cells existed before the imatinib therapy. These results suggest that leukemic subclones carrying a genetic perturbation of the targeted molecules for both imatinib and rituximab were present before the therapies. The preexistence of primary resistant clones suggests the inability of combination therapy with 2 molecularly targeted drugs to overcome drug resistance in leukemia.
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PMID:Existence of leukemic clones resistant to both imatinib mesylate and rituximab before drug therapies in a patient with Philadelphia chromosome-positive acute lymphocytic leukemia. 1529 70

In the last twenty years, using all-trans retinoic acid (ATRA) as a differentiation inducer, Shanghai Institute of Hematology has achieved an important breakthrough in the treatment of acute promyelocytic leukemia (APL), which realized the theory of reversing phenotype of cells and provided a successful model of differentiation therapy in cancers. Our group first discovered in the world the variant chromosome translocation t(11;17)(q23;q21) of APL, and cloned the PML-RAR alpha, PLZF-RAR alpha and NPM-RAR alpha fusion genes corresponding to the characterized chromosome translocations t(15;17); t(11;17) and t(5;17) in APL. Moreover, establishment of transgenic mice model of APL proved their effects on leukemogenesis. The ability of ATRA to modify the recruitment of nuclear receptor co-repressor with PML-RAR alpha but not PLZF-RAR alpha caused by the variant chromosome translocation elucidated the therapeutic mechanism of ATRA from the molecular level and provides new insight into transcription-modulating therapy. Since 1994, our group has successfully applied arsenic trioxide (As(2)O(3)) in treating relapsed APL patients, with the complete remission rate of 70% - 80%. The molecular mechanism study revealed that As(2)O(3) exerts a dose-dependent dual effect on APL. Low-dose As(2)O(3) induced partial differentiation of APL cells, while the higher dose induced apoptosis. As(2)O(3) binds ubiquitin like SUMO-1 through the lysine 160 of PML, resulting in the degradation of PML-RAR alpha. Taken together, ATRA and As(2)O(3) target the transcription factor PML-RAR alpha, the former by retinoic acid receptor and the latter by PML sumolization, both induce PML-RAR alpha degradation and APL cells differentiation and apoptosis. Because of the different acting pathways, ATRA and As(2)O(3) have no cross-resistance and can be used as combination therapy. Clinical trial in newly diagnosed APL patients showed that ATRA/As(2)O(3) in combination yields a longer disease-free survival time. With the median survival of 18 months, none of the 20 cases in combination treatment relapsed, whereas 7 relapsed in 37 cases in mono-treatment. This is the best clinical effect achieved in treating adult acute leukemia to this day, possibly making APL the first adult curable leukemia. Based on the great success of the pathogenetic gene target therapy in APL, this strategy may extend to other leukemias. Combination of Gleevec and arsenic agents in treating chronic myeloid leukemia has already make a figure both in clinical and laboratory research, aiming at counteracting the abnormal tyrosine kinase activity of ABL and the degradating BCR-ABL fusion protein. In acute myeloid leukemia M(2b), using new target therapy degradating AML1-ETO fusion protein and reducing the abnormal tyrosine kinase activity of c-kit will also lead to new therapeutic management in acute leukemias.
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PMID:[Basic and clinical studies of the gene product-targeting therapy based on leukemogenesis--editorial]. 1574 26

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


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