Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0023473 (chronic myeloid leukemia)
 18,916 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The Philadelphia chromosome translocation generates a chimeric oncogene, BCR/ABL, which causes chronic myelogenous leukemia (CML). In primary neutrophils from patients with CML, the major novel tyrosine-phosphorylated protein is CRKL, an SH2-SH3-SH3 linker protein which has an overall homology of 60% to CRK, the human homologue of the v-crk oncogene product. Anti-CRKL immunoprecipitates from CML cells, but not normal cells, were found to contain p210BCR/ABL and c-ABL. Several other phosphoproteins were also detected in anti-CRKL immunoprecipitates, one of which has been identified as paxillin, a 68-kDa focal adhesion protein which we have previously shown to be phosphorylated by p210BCR/ABL. Using GST-CRKL fusion proteins, the SH3 domains of CRKL were found to bind c-ABL and p210BCR/ABL, while the SH2 domain of CRKL bound to paxillin, suggesting that CRKL could physically link p210BCR/ABL to paxillin. Paxillin contains three tyrosines in Tyr-X-X-Pro (Y-X-X-P) motifs consistent with amino acid sequences predicted to be optimal for binding to the CRKL-SH2 domain (at positions Tyr-31, Tyr-118, and Tyr-181). Each of these tyrosine residues was mutated to a phenylalanine residue, and in vitro binding assays indicated that paxillin tyrosines at positions 31 and 118, but not 181, are likely to be involved in CRKL-SH2 binding. These results suggest that the p210BCR/ABL oncogene may be physically linked to the focal adhesion-associated protein paxillin in hematopoietic cells by CRKL. This interaction could contribute to the known adhesive defects of CML cells.
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PMID:CRKL links p210BCR/ABL with paxillin in chronic myelogenous leukemia cells. 749 40

Chronic myelogenous leukemia (CML) is characterized by the presence of the Philadelphia (Ph) chromosome in clonally derived hematopoietic precursors and their progeny. The Ph chromosome arises from a translocation that deregulates the c-ABL protein tyrosine kinase, giving it transforming potential and increased kinase activity. We observed a unique 39-kD tyrosine phosphoprotein (pp39), previously reported in blastic CML cell lines, in neutrophils from 50 cases of chronic phase CML. This protein was prominently and constitutively tyrosine-phosphorylated in CML neutrophils and was not phosphorylated in normal neutrophils. Stimulation of normal neutrophils with cytokines and agonists did not induce tyrosine phosphorylation of proteins migrating in the region of pp39, and the phosphorylation state of pp39 in CML neutrophils was not affected by kinase inhibitors known to downregulate the ABL kinase. The pp39 was not phosphorylated in hematopoietic cells from healthy donors or from patients with Ph chromosome-negative myeloproliferative disorders. Using micro amino acid sequencing of purified preparations of pp39, we identified pp39 as CRKL protein, which is consistent with recent immunologic studies in the blastic K562 cell line. Immunoblotting with anti-CRKL antibodies showed the presence of CRKL protein in CML cells and cell lines as well as in antiphosphotyrosine immunoprecipitates from CML cells. Our results suggest that pp39 CRKL in CML neutrophils may be stably tyrosine-phosphorylated by the BCR/ABL kinase at an early stage of myeloid differentiation when the ABL kinase is active. CRK, CRKL, and other SH2 (SRC homology domain)/SH3-containing proteins function as adaptor molecules in nonreceptor tyrosine kinase signalling pathways. Although the CRKL protein is present in normal neutrophils, it is not tyrosine-phosphorylated, and the inability to induce such phosphorylation in normal neutrophils suggests a special role of this phosphoprotein in the pathogenesis of CML. Constitutive phosphorylation of CRKL is unique to CML, indicating that it may be a useful target for therapeutic intervention.
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PMID:Identification of CRKL as the constitutively phosphorylated 39-kD tyrosine phosphoprotein in chronic myelogenous leukemia cells. 752 58

Chronic myelogenous leukemia (CML) and some acute lymphoblastic leukemias (ALL) are caused by the t(9;22) chromosome translocation, which produces the constitutively activated BCR/ABL tyrosine kinase. When introduced into factor dependent hematopoietic cell lines, BCR/ABL induces the tyrosine phosphorylation of many cellular proteins. One prominent BCR/ABL substrate is p120CBL, the cellular homolog of the v-Cbl oncoprotein. In an effort to understand the possible contribution of p120CBL to transformation by BCR/ABL, we looked for cellular proteins which associate with p120CBL in hematopoietic cell lines transformed by BCR/ABL. In addition to p210BCR/ABL and c-ABL, p120CBL coprecipitated with an 85 kDa phosphoprotein, which was identified as the p85 subunit of PI3K. Anti-p120CBL immunoprecipitates from BCR/ABL-transformed, but not from untransformed, cell lines contained PI3K lipid kinase activity. Interestingly, the adaptor proteins CRKL and c-CRK were also found in these complexes. In vitro binding studies indicated that the SH2 domains of CRKL and c-CRK bound directly to p120CBL, while the SH3 domains of c-CRK and CRKL bound to BCR/ABL and c-ABL. The N-terminal and the C-terminal SH2 and the SH3 domain of p85PI3K bound directly in vitro to p120CBL. The ABL-SH2, but not ABL-SH3, could also bind to p120CBL. These data suggest that BCR/ABL may induce the formation of multimeric complexes of signaling proteins which include p120CBL, PI3K, c-CRK or CRKL, c-ABL and BCR/ABL itself.
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PMID:The proto-oncogene product p120CBL and the adaptor proteins CRKL and c-CRK link c-ABL, p190BCR/ABL and p210BCR/ABL to the phosphatidylinositol-3' kinase pathway. 863 6

The Philadelphia chromosome translocation generates a chimeric oncogene, BCR/ABL which causes chronic myelogenous leukemia. Two different fusion proteins can be produced, p190BCR/ABL and p210BCR/ABL, depending on the location of the breakpoint in BCR. Although the ABL tyrosine kinase activity of the resulting oncoprotein is essential for transformation, the exact functional contribution of BCR to transformation is unclear. A novel oncogene containing ABL is formed by the (9;12) translocation which fuses part of the ets-family member TEL to c-ABL in patients with acute leukemia. In an effort to compare the biological effects of various ABL oncogenes, we transformed two different factor-dependent murine hematopoietic cell lines with cDNA's encoding p210BCR/ABL, p190BCR/ABL, or TEL/ABL. Transfection of each of the three activated ABL oncogenes resulted in rapid emergence of growth factor-independence, and 2-4 sublines from each cell line with each oncogene were further studied. Each oncogene induced an increase in the tyrosine phosphorylation of cellular proteins and autophosphorylation of the oncoprotein itself. Overall, the pattern of increased tyrosine phosphorylation was similar in the cell lines, suggesting that many of the major substrates were identical. We specifically examined a series of proteins known to be p210BCR/ABL substrates, including rasGAP, Shc, SH-PTP2, SH-PTP1, CRK-L, CBL, paxillin, and STATs, and found that each were also tyrosine phosphorylated in response to p190BCR/ABL and TEL/ABL. These results suggest that the function of BCR can be largely replaced by the unrelated protein TEL with regards to transformation of murine hematopoietic cell lines to factor-independence, and support the hypothesis that a major contribution of both fusion partners is to activate the ABL tyrosine kinase.
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PMID:p210BCR/ABL, p190BCR/ABL, and TEL/ABL activate similar signal transduction pathways in hematopoietic cell lines. 880 88

The Philadelphia chromosome translocation generates a chimeric oncogene, BCR/ABL, which causes chronic myelogenous leukemia (CML). In primary leukemic neutrophils from patients with CML, the major tyrosine phosphorylated protein is CRKL, an SH2-SH3-SH3 adapter protein which has an overall homology of 60% to CRK, the human homologue of the v-crk oncogene. In cell lines transformed by BCR/ABL, CRKL was tyrosine phosphorylated, while CRK was not. We looked for changes in CRK- and CRKL-binding proteins in Ba/F3 hematopoietic cell lines which were transformed by BCR/ABL. Anti-CRK II or anti-CRKL immunoprecipitates were probed by far Western blotting with CRK II- or CRKL-GST fusion proteins to display CRK- and CRKL-coprecipitating proteins. There was a striking qualitative difference in the proteins coprecipitating with CRKL and CRK II. In untransformed cells, three major proteins coprecipitated with CRKL, identified as C3G, SOS and c-ABL. Each of these proteins was found to interact with the CRKL-SH3 domains, but not the SH2 domain. After BCR/ABL transformation, the CRKL SH3-domain binding proteins did not change, with the exception that BCR/ABL now coprecipitated with CRKL. Compared to CRKL, very few proteins coprecipitated with CRK II in untransformed, quiescent cells. After BCR/ABL transformation, both the CRKL- and CRK-SH2 domains bound to a new complex of proteins of approximate molecular weight 105-120 kDa. The major protein in this complex was identified as p120CBL. Thus, in these hematopoietic cell lines, CRKL is involved to a greater extent than CRK II in normal signaling pathways that involve c-ABL, C3G and SOS. In BCR/ABL-transformed cells, CRKL but not CRK II, appears to form complexes which potentially link BCR/ABL, c-ABL, C3G, and SOS to the protooncoprotein, p120CBL.
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PMID:The BCR/ABL oncogene alters interaction of the adapter proteins CRKL and CRK with cellular proteins. 906 77

CRKL is a 39 kDa adapter protein, originally cloned in proximity to the BCR gene on chromosome 22, which has a key regulatory role in hematopoietic cells. CRKL has one SH2 and two SH3 domains, with 60% homology to CRK II. CRKL is a prominent substrate of the BCR/ABL oncoprotein in chronic myelogenous leukemia and binds to both BCR/ABL and c-ABL. CRKL has been shown to be tryosine phosphorylated in response to normal hematopoietic growth factor receptor signaling with ligands such as thrombopoietin, erythropoietin or steel factor. Additionally, CRKL is involved in signaling initiated by crosslinking of beta integrins, and B cell or T cell receptors. Structurally, the amino-terminal SH3 domain of CRKL has been shown to bind proteins such as C3G, SOS, PI3-K, c-ABL or BCR/ABL. The SH2 domain of CRKL can bind to tyrosine phosphorylated proteins such as CBL, HEF1, CAS or paxillin. This review summarizes the current knowledge on the function of this unique adapter protein in normal hematopoietic and leukemic cell signaling.
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PMID:Role of the adapter protein CRKL in signal transduction of normal hematopoietic and BCR/ABL-transformed cells. 959 59

CRKL (CRK-like) is an adapter protein predominantly phosphorylated in cells that express the tyrosine kinase p210(BCR-ABL), the fusion product of a (9;22) chromosomal translocation causative for chronic myeloid leukemia. It has been unclear, however, whether CRKL plays a functional role in p210(BCR-ABL) transformation. Here, we show that CRKL is required for p210(BCR-ABL) to support interleukin-3-independent growth of myeloid progenitor cells and long-term outgrowth of B-lymphoid cells from fetal liver-derived hematopoietic progenitor cells. Furthermore, a synthetic phosphotyrosyl peptide that binds to the CRKL SH2 domain with high affinity blocks association of endogenous CRKL with the p210(BCR-ABL) complex and reduces c-MYC levels in K562 human leukemic cells as well as in mouse hematopoietic cells transformed by p210(BCR-ABL) or the imatinib-resistant mutant T315I. These results indicate that the function of CRKL as an adapter protein is essential for p210(BCR-ABL)-induced transformation.
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PMID:A specific need for CRKL in p210BCR-ABL-induced transformation of mouse hematopoietic progenitors. 2080 13

The antihypertensive drug amiloride is being considered as a tactic to improve cancer therapy including that for chronic myelogenous leukemia. In this study, we show that amiloride modulates the alternative splicing of various cancer genes, including Bcl-x, HIPK3, and BCR/ABL, and that this effect is not mainly related to pH alteration, which is a known effect of the drug. Splice modulation involved various splicing factors, with the phosphorylation state of serine-arginine-rich (SR) proteins also altered during the splicing process. Pretreatment with okadaic acid to inhibit protein phosphatase PP1 reversed partially the phosphorylation levels of SR proteins and also the amiloride-modulated yields of Bcl-xs and HIPK3 U(-) isoforms. Genome-wide detection of alternative splicing further revealed that many other apoptotic genes were regulated by amiloride, including APAF-1, CRK, and SURVIVIN. Various proteins of the Bcl-2 family and MAPK kinases were found to be involved in amiloride-induced apoptosis. Moreover, the effect of amiloride on mRNA levels of Bcl-x was demonstrated to translate to the protein levels. Cotreatment of K562 and BaF3/Bcr-AblT315I cells with amiloride and imatinib induced more loss of cell viability than either agent alone. Our findings suggest that amiloride may offer a potential treatment option for chronic myelogenous leukemia either alone or in combination with imatinib.
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PMID:Amiloride modulates alternative splicing in leukemic cells and resensitizes Bcr-AblT315I mutant cells to imatinib. 2122 52

The signaling adapter protein CRK is an indispensable molecule involved in regulating the malignant potential of human cancers. CRK-like (CRKL) is a hematopoietic cell-dominant homologue of CRK that is reported to be phosphorylated by BCR-ABL tyrosine kinase in chronic myelogenous leukemia patients, but its biological function in non-hematopoietic tumors remains unclear. In this study, we explored the tumorigenic role of CRKL in head and neck squamous cell carcinoma (HNSCC) in vitro and in vivo. Immunoprecipitation analysis of HNSCC cell line, HSC-3 cells, showed that the dominant binding partner for C3G was CRKL, not CRK. To clarify the molecular function of CRKL, we established lentiviral shRNA-mediated CRKL-knockdown HNSCC cell lines. In CRKL-knockdown HSC-3 and HSC-4 cells, cell growth and motility were diminished compared to control cells. Cell adhesion assays showed that cell attachment onto both fibronectin- and collagen-coated dishes was significantly suppressed in CRKL-knockdown HSC-3 cells, while no significant change was observed for poly-l-lysine-coated dishes. Immunofluorescence staining revealed that focal adhesion was reduced in CRKL-knockdown HSC-3 cells. With a pulldown assay, CRKL-knockdown HSC-3 cells showed decreased amounts of active Rap1 compared to control cells. Moreover, in an in vivo assay, tumor formation of CRKL-knockdown HSC-3 cells in nude mice was significantly abrogated. Our results indicate that CRKL regulates HNSCC-cell growth, motility, and integrin-dependent cell adhesion, suggesting that CRKL plays a principal role in HNSCC tumorigenicity.
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PMID:CRKL plays a pivotal role in tumorigenesis of head and neck squamous cell carcinoma through the regulation of cell adhesion. 2224 89

Chronic myeloid leukemia (CML) is a severe problem throughout the world and requires identification of novel targets for its treatment. This multifactorial disease accounts for about 15% of the all diagnosed leukemia cases. Mitogen-activated protein kinase (MAPK) signaling pathway is crucial for the cell survival and its dysregulation is being implicated in various types of cancers. In here, we have discussed the potential role of various miRNAs that are found involved in regulating the proteins cascades of MAPK signaling pathway associated with CML. An emphasis has been paid to summarize the influence of various miRNAs in elevating or suppressing the expression level of significant proteins such as miR-203, miR-196a, miR-196b, miR-30a, miR-29b, miR-138 in BCR-ABL tyrosine kinase; miR-126, miR-221, miR-128, miR-15a, miR-188-5p, miR-17 in CRK family proteins; miR-155, miR-181a with SOS proteins; miR-155, miR-19a, with KRAS proteins; miR-19a with RAF1 protein; and miR-17, miR-19a, miR-17-92 cluster with MAPK/ERK proteins. In light of ever-increasing importance and ever-widening regulatory roles of miRNAs in cells, we have reviewed the recent progress in the field of miRNAs and have tried to suggest them as controlling targets for various protein cascades of MAPK signaling pathway. An understanding of the supervisory mechanism of MAPK by miRNAs might provide novel targets for treating CML.
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PMID:MicroRNAs mediated regulation of MAPK signaling pathways in chronic myeloid leukemia. 2696 56


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