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)

Activating mutations in JAK1 have been reported in acute lymphoblastic leukemias, but little is known about the mechanisms involved in their constitutive activation. Here, we studied the ability of JAK1 V658F and A634D to activate the Janus kinase (JAK)/STAT pathway upon ectopic expression in HEK293 cells alone or together with the other components of the interleukin-9 receptor complex (IL-9Ralpha, gammac, and JAK3). Expression of JAK1 mutants alone failed to trigger STAT activation, but co-expression of the IL-9Ralpha chain promoted JAK1 mutant phosphorylation and STAT activation. Mutation of the FERM domain of JAK1, which is critical for cytokine receptor association, or of the single tyrosine of IL-9Ralpha involved in STAT recruitment abolished this activity, indicating that JAK1 mutants need to associate with a functional IL-9Ralpha to activate STAT factors. Several lines of evidence indicated that IL-9Ralpha homodimerization was involved in this process. IL-9Ralpha variants with mutations of the JAK-interacting BOX1 region not only failed to promote JAK1 activation but also acted as dominant negative forms reverting the effect of wild-type IL-9Ralpha. Coimmunoprecipitation experiments also showed the formation of IL-9Ralpha homodimers. Interestingly, STAT activation was partially inhibited by expression of gammac, suggesting that overlapping residues are involved in IL-9Ralpha homodimerization and IL-9Ralpha/gammac heterodimerization. Co-expression of wild-type JAK3 partially reverted the inhibition by gammac, indicating that JAK3 cooperates with JAK1 mutants within the IL-9 receptor complex. Similar results were observed with IL-2Rbeta. Taken together, our results show that IL-9Ralpha and IL-2Rbeta homodimers efficiently mediate constitutive activation of ALL-associated JAK1 mutants.
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PMID:Acute lymphoblastic leukemia-associated JAK1 mutants activate the Janus kinase/STAT pathway via interleukin-9 receptor alpha homodimers. 1913 2

Mutant tyrosine kinases are common in cancer and can be therapeutically targeted with kinase inhibitors. To obtain insight in the contribution of activated kinases to the pathogenesis ofT-cell acute lymphoblastic leukemia (T-ALL), we studied the NUP214-ABL1 fusion gene that is found in 6% of T-ALL and EML1-ABL1 that we identified in one T-ALL patient. NUP214-ABL1 and EML1-ABL1 display constitutive kinase activity and are sensitive to the kinase inhibitor imatinib. Both proteins transform hematopoietic cells and we established mouse models of EML1-ABL1 and NUP214-ABL1 induced T-ALL. Interestingly, whereas EML1-ABL1 activity requires homo-oligomerization via its coiled coil domain, activity of NUP214-ABL1 depends on its cellular localization to the nuclear pore complexes. These results for NUP214-ABL1 delineate a novel mechanism for fusion kinase activation in cancer and provide new options to interfere with NUP214-ABL1 activity. T-ALL development requires accumulation of different mutations. Little is known about the cooperation between the mutations and about their sequence of accumulation. We provide evidence that tyrosine kinase mutations occur late in T-ALL development, suggesting limited potential for kinase inhibitor monotherapy. We therefore combined NUP214-ABL1 inhibition with other therapies and show that inhibition of NUP214-ABL1 and NOTCH1 in vitro can result in synergistic effects. Further validation of these and other combination therapies requires animal models containing several of the mutations in T-ALL and thus reflecting the multistep oncogenic process of human T-ALL genesis. The models for ABL1 fusion induced T-ALL will serve as starting point here.
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PMID:ABL1 fusions in T-cell acute lymphoblastic leukemia. 1916 98

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

Many leukemias could have chromosomic translocations and according to the transcripts formed by the genes involved, the patients present an specific phenotype of the leukemia. We show the first results of the investigation of the gen BCR-ABL using RT-PCR, in order to look for the t(9;22)(q34;q11) in pediatric leukemic children. We studied in total 55 patients, 6 (10.9%) of them were positive for that translocation. Two (3.63%) of the positive children had ALL and the other 4 (7.27%) presented CML, the genotyping analysis of the transcript was studied in these children. With the introduction of this methodology as part of the routine studies, the leukemic children could get in the future an specific diagnosis, that will be important to classify them in prognostic categories and to improve the detection of minimal residual disease.
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PMID:[Molecular detection of the BCR-ABL gen by RT-PCR in Costa Rican children with leukemia]. 1941 69

Dasatinib, an oral inhibitor of multiple tyrosine kinases, including BCR-ABL, Src, and platelet-derived growth factor receptor, was approved for patients with imatinib-resistant or -intolerant chronic myeloid leukemia (CML) or Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Dasatinib demonstrated efficacy with a well-tolerated safety profile in all phases of CML and Ph+ ALL, which led to its 2006 approval by the U.S. Food and Drug Administration for clinical use. However, although most adverse events are grade 1 or 2, a number of adverse events require management and monitoring to ensure that patients can continue receiving the treatment. This review discusses the appropriate nursing management of key adverse events (cytopenias, fluid retention, bleeding, gastrointestinal toxicity, and cardiotoxicity) to ensure that patients gain maximum benefit from this multitargeted agent.
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PMID:Practical management of dasatinib for maximum patient benefit. 1950 92

Recent work indicates that an Aurora kinase inhibitor MK-0457 (VX-680), a small-molecule inhibitor of Aurora kinases A, B, C and BCR-ABL, FLT-3, JAK-2, can block the progression of cell growth cycle, causing apoptosis in a range of human tumors. MK-0457 has the activity against expressions of wild-type and mutated bcr-abl gene, including the T315I mutant, and can inhibit the activity of FLT-3, JAK-2 and their mutated types as well. Clinical applications suggest that the MK-0457 has therapeutic effect on the highly refractory CML and CML with poor prognosis, Ph(+) ALL with T315I mutant, relapse refractory AML and JAK-2 positive myeloproliferative diseases (MPD). The intensive preclinical studies and the on-going phase II clinical trials will open up a new vista of therapy for some hematological malignancies. This review focuses on the pharmacologic action of MK-0457 and its clinical trial as well as combined application.
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PMID:[Research progress on aurora kinase inhibitor MK-0457 in therapy for some hematological malignancies -- review]. 1954 14

We report 2 novel, cryptic chromosomal abnormalities in precursor B-cell acute lymphoblastic leukemia (BCP-ALL): a translocation, either t(X;14)(p22;q32) or t(Y;14)(p11;q32), in 33 patients and an interstitial deletion, either del(X)(p22.33p22.33) or del(Y)(p11.32p11.32), in 64 patients, involving the pseudoautosomal region (PAR1) of the sex chromosomes. The incidence of these abnormalities was 5% in childhood ALL (0.8% with the translocation, 4.2% with the deletion). Patients with the translocation were older (median age, 16 years), whereas the patients with the deletion were younger (median age, 4 years). The 2 abnormalities result in deregulated expression of the cytokine receptor, cytokine receptor-like factor 2, CRLF2 (also known as thymic stromal-derived lymphopoietin receptor, TSLPR). Overexpression of CRLF2 was associated with activation of the JAK-STAT pathway in cell lines and transduced primary B-cell progenitors, sustaining their proliferation and indicating a causal role of CRLF2 overexpression in lymphoid transformation. In Down syndrome (DS) ALL and 2 non-DS BCP-ALL cell lines, CRLF2 deregulation was associated with mutations of the JAK2 pseudokinase domain, suggesting oncogenic cooperation as well as highlighting a link between non-DS ALL and JAK2 mutations.
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PMID:Deregulated expression of cytokine receptor gene, CRLF2, is involved in lymphoid transformation in B-cell precursor acute lymphoblastic leukemia. 1964 Nov 90

MLL-AF4 fusion is a hallmark genetic abnormality in infant B-acute lymphoblastic leukemia (B-ALL) known to arise in utero. The cellular origin of leukemic fusion genes during human development is difficult to ascertain. The bone marrow (BM) microenvironment plays an important role in the pathogenesis of several hematological malignances. BM mesenchymal stem cells (BM-MSC) from 38 children diagnosed with cytogenetically different acute leukemias were screened for leukemic fusion genes. Fusion genes were absent in BM-MSCs of childhood leukemias carrying TEL-AML1, BCR-ABL, AML1-ETO, MLL-AF9, MLL-AF10, MLL-ENL or hyperdiploidy. However, MLL-AF4 was detected and expressed in BM-MSCs from all cases of MLL-AF4(+) B-ALL. Unlike leukemic blasts, MLL-AF4(+) BM-MSCs did not display monoclonal Ig gene rearrangements. Endogenous or ectopic expression of MLL-AF4 exerted no effect on MSC culture homeostasis. These findings suggest that MSCs may be in part tumor-related, highlighting an unrecognized role of the BM milieu on the pathogenesis of MLL-AF4(+) B-ALL. MLL-AF4 itself is not sufficient for MSC transformation and the expression of MLL-AF4 in MSCs is compatible with a mesenchymal phenotype, suggesting a differential impact in the hematopoietic system and mesenchyme. The absence of monoclonal rearrangements in MLL-AF4(+) BM-MSCs precludes the possibility of cellular plasticity or de-differentiation of B-ALL blasts and suggests that MLL-AF4 might arise in a population of prehematopoietic precursors.
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PMID:Bone marrow mesenchymal stem cells from infants with MLL-AF4+ acute leukemia harbor and express the MLL-AF4 fusion gene. 1999 53

Copy number losses in chromosome arm 9p are well-known aberrations in malignancies, including leukemias. The CDKN2A gene is suggested to play a key role in these aberrations. In this study overviewing 9p losses in hematologic neoplasias, we introduce the term focal 9p instability to indicate multiple areas of copy number loss or homozygous loss within a larger heterozygous one in 9p. We have used microarray comparative genomic hybridization to study patients with acute lymphoblastic leukemia (ALL, n = 140), acute myeloid leukemia (n = 50), chronic lymphocytic leukemia (n = 20), and myelodysplastic syndromes (n = 37). Our results show that 9p instability is restricted to ALL. In total, 58/140 (41%) patients with ALL had a loss in 9p. The 9p instability was detected in 19% of the patients with ALL and always included homozygous loss of CDKN2A along with loss of CDKN2B. Other possibly important genes included MTAP, IFN, MLLT3, JAK2, PTPLAD2, and PAX5. 13/27 (48%) patients with the instability had the BCR/ABL1 fusion gene or other oncogene-activating translocation or structural aberrations. Two patients had homozygous loss of hsa-mir -31, a microRNA known to regulate IKZF1. IKZF1 deletion at 7p12.1 was seen in 10 (37%) patients with the 9p instability. These findings suggest that, in ALL leukemogenesis, loss of CDKN2A and other target genes in the instability region is frequently associated with BCR/ABL1 and IKZF1 dysfunction. The multiple mechanisms leading to 9p instability including physical or epigenetic loss of the target genes, loss of the microRNA cluster, and the role of FRA9G fragile site are discussed.
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PMID:Focal 9p instability in hematologic neoplasias revealed by comparative genomic hybridization and single-nucleotide polymorphism microarray analyses. 2001 97

The BCR-ABL inhibitor imatinib revolutionized the treatment of chronic myeloid leukemia (CML). However, resistance and intolerance to imatinib have emerged as substantial clinical issues. The mechanisms underlying resistance are multifactorial and may include mutations in the kinase domain of BCR-ABL, increased production of BCR-ABL, or activation of BCR-ABL-independent pathways. Two second-line BCR-ABL inhibitors are now approved for treatment of patients with resistance or intolerance to imatinib. Dasatinib is a dual BCR-ABL/Src-family kinase (SFK) inhibitor approved for patients with imatinib-resistant and -intolerant CML in any phase and Ph+ ALL. Nilotinib, an analogue of imatinib, is approved for the treatment of imatinib-resistant or -intolerant patients with chronic or accelerated phase CML. Both agents have shown significant clinical activity in patients with imatinib-resistant or -intolerant CML, and their approval represents a major advancement in the treatment options available. Choosing the most appropriate treatment after imatinib failure may be critical in attaining the best possible long-term prognosis. The presence of certain disease characteristics (e.g. specific BCR-ABL mutations) or patient comorbidities may facilitate more effective treatment. In this review, we discuss mechanisms of imatinib resistance and preclinical and clinical data with dasatinib and nilotinib which may have potential use for guiding second-line treatment decisions.
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PMID:Use of dasatinib and nilotinib in imatinib-resistant chronic myeloid leukemia: translating preclinical findings to clinical practice. 2003 31


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