Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0023467 (acute myeloid leukemia)
 35,200 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mixed lineage leukemia gene (MLL, also known as HRX, ALL-1 and Htrx) located at 11q23 is involved in translocations with over 40 different chromosomal bands in a variety of leukemia subtypes. Here we report our analysis of a rare but recurring translocation, t(11;15)(q23;q14). This translocation has been described in a small subset of cases with both acute myeloblastic leukemia and ALL. Recent studies have shown that MLL is fused to AF15q14 in the t(11;15). Here we analyse a sample from another patient with this translocation and confirm the presence of an MLL-AF15q14 fusion. However, we have also identified and cloned another fusion transcript from the same patient sample. In this fusion transcript, MLL is fused to a novel gene, MLL partner containing FYVE domain (MPFYVE). Both MLL-AF15q14 and MLL-MPFYVE are in-frame fusion transcripts with the potential to code for novel fusion proteins. MPFYVE is also located on chromosome 15, approximately 170 kb telomeric to AF15q14. MPFYVE contains a highly conserved motif, the FYVE domain which, in other proteins, has been shown to bind to phosphotidyl-inositol-3 phosphate (PtdIns(3)P). The MLL-MPFYVE fusion may be functionally important in the leukemia process in at least some patients containing this translocation.
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PMID:A t(11;15) fuses MLL to two different genes, AF15q14 and a novel gene MPFYVE on chromosome 15. 1261 66

The c-Kit proto-oncogene is a receptor protein-tyrosine kinase associated with several highly malignant human cancers. Upon binding its ligand, stem cell factor (SCF), c-Kit forms an active dimer that autophosphorylates itself and activates a signaling cascade that induces cell growth. Disease-causing human mutations that activate SCF-independent constitutive expression of c-Kit are found in acute myelogenous leukemia, human mast cell disease, and gastrointestinal stromal tumors. We report on the phosphorylation state and crystal structure of a c-Kit product complex. The c-Kit structure is in a fully active form, with ordered kinase activation and phosphate-binding loops. These results provide key insights into the molecular basis for c-Kit kinase transactivation to assist in the design of new competitive inhibitors targeting activated mutant forms of c-Kit that are resistant to current chemotherapy regimes.
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PMID:Structure of a c-kit product complex reveals the basis for kinase transactivation. 1282 76

Stabilization of cell surface antigens and preservation of ultrastructural integrity are important aspects of immunoelectron microscopical studies. In the present study, 4 anti-syndecan-1/CD138 (B-B2, B-B4, MI15, 1D4) monoclonal antibodies (mAbs) were applied in combination with periodatelysine-paraformaldehyde (PLP) fixation and indirect pre-embedding peroxidase electron microscopical immunocytochemistry to analyse the localization and function of these molecules in normal myeloid cells, acute lymphoblastic leukemia (ALL) cells and acute myeloblastic leukemia (AML) cells. One case of normal human bone marrow, 3 cases of untreated AML and 2 cases of untreated ALL were studied. Samples were immediately fixed for 4 h in freshly-prepared PLP fixative in 0.037 mol/L phosphate buffer, pH 7.4, containing 10 mmol/L sodium metaperiodate, 75 mmol/L lysine, and 2% paraformaldehyde. Expression of syndecan-1 was found at the plasma membrane of all cell types. Staining intensity at the membrane of AML cells was stronger than that on the membrane of normal myeloid and ALL cells. We conclude that anti-syndecan-1/CD138 mAbs in combination with the method described here are a suitable tool for detection of cell surface syndecan molecules in cells originating from progenitor cells that can differentiate in both myeloid and lymphoid cells.
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PMID:Syndecan-1/CD138 expression in normal myeloid, acute lymphoblastic and myeloblastic leukemia cells. 1367 14

We examined the involvement of sphingosine kinase-1, a critical regulator of the sphingolipid balance, in susceptibility to antineoplastic agents of either sensitive or multidrug-resistant acute myeloid leukemia cells. Contrary to parental HL-60 cells, doxorubicin and etoposide failed to trigger apoptosis in chemoresistant HL-60/Doxo and HL-60NP16 cells overexpressing MRP1 and MDR1, respectively. Chemosensitive HL-60 cells displayed sphingosine kinase-1 inhibition coupled with ceramide generation. In contrast, chemoresistant HL-60/ Doxo and HL-60/VP16 had sustained sphingosine kinase-1 activity and did not produce ceramide during treatment. Enforced expression of sphingosine kinase-1 in chemosensitive HL-60 cells resulted in marked inhibition of apoptosis that was mediated by blockade of mitochondrial cytochrome c efflux hence suggesting a control of apoptosis at the pre-mitochondrial level. Incubation with cell-permeable ceramide of chemoresistant cells led to a sphingosine kinase-1 inhibition and apoptosis both prevented by sphingosine kinase-1 over-expression. Furthermore, F-12509a, a new sphingosine kinase inhibitor, led to ceramide accumulation, decrease in sphingosine 1-phosphate content and caused apoptosis equally in chemosensitive and chemoresistant cell lines that is inhibited by adding sphingosine 1-phosphate or overexpressing sphingosine kinase-1. F-12509a induced classical apoptosis hallmarks namely nuclear fragmentation, caspase-3 cleavage as well as downregulation of antiapoptotic XIAP, and release of cytochrome c and SMAC/Diablo.
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PMID:Overcoming MDR-associated chemoresistance in HL-60 acute myeloid leukemia cells by targeting sphingosine kinase-1. 1628 Oct 67

Fourier transform infrared (FTIR)-spectroscopy has been found useful for monitoring the effectiveness of drugs during chemotherapy in leukemia patients. In the present work, spectral changes that occurred in the white blood cells (WBC) of an adult acute myeloid leukemia (AML) patient and their possible utilization for monitoring biochemistry of WBC were investigated. The phosphate absorbance from nucleic acids and the lipid-protein ratio in the WBC decreased immediately after treatment and then increased to levels of a control group. Similar observations were recorded in child patients with acute lymphoblastic leukemia (ALL) who were used as test cases. These parameters maybe used as possible markers to indicate successful remission and suggest that FTIR-spectroscopy may provide a rapid optical method for continuous monitoring or evaluation of a WBC population.
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PMID:Continuous monitoring of WBC (biochemistry) in an adult leukemia patient using advanced FTIR-spectroscopy. 1630 98

G-CSFR cytoplasmic tyrosine (Y) residues (Y704, Y729, Y744, and Y764) become phosphorylated upon ligand binding and recruit specific Src homology 2 domain-containing proteins that link to distinct yet overlapping programs for myeloid cell survival, differentiation, proliferation, and activation. The structural basis for recruitment specificity is poorly understood but could be exploited to selectively target deleterious G-CSFR-mediated signaling events such as aberrant Stat3 activation demonstrated in a subset of acute myeloid leukemia patients with poor prognosis. Recombinant Stat3 bound to G-CSFR phosphotyrosine peptide ligands pY704VLQ and pY744LRC with similar kinetics. Testing of three models for Stat3 Src homology 2-pY ligand binding in vitro and in vivo revealed unique determinants for Stat3 recruitment and activation by the G-CSFR, the side chain of Stat3 R609, which interacts with the pY ligand phosphate group, and the peptide amide hydrogen of E638, which bonds with oxygen/sulfur within the + 3 Q/C side chain of the pY ligand when it assumes a beta turn. Thus, our findings identify for the first time the structural basis for recruitment and activation of Stat3 by the G-CSFR and reveal unique features of this interaction that can be exploited to target Stat3 activation for the treatment of a subset of acute myeloid leukemia patients.
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PMID:Unique structural determinants for Stat3 recruitment and activation by the granulocyte colony-stimulating factor receptor at phosphotyrosine ligands 704 and 744. 1649 51

Tumor-associated peptides isolated by acid elution are frequently used for therapeutic immunization against various tumors both in mice and in humans. In acute myeloid leukemia (AML), the frequent accessibility of a large tumor burden allows for extraction of peptides from leukemia cells by using either citrate-phosphate (CP) or trifluoroacetic acid (TFA) buffer. To develop an optimal immunotherapeutic protocol for AML patients, we evaluated both in mice and in humans, the immunogenicity of peptides eluted from leukemia cells with the two acids (TFA or CP). Although ex vivo studies in mice showed that both prophylactic immunizations with mature dendritic cells (DC) loaded with TFA-peptides (DC/TFA), or CP-peptides (DC/CP), were able to stimulate specific antileukemia immune responses, only vaccination with DC/TFA was able to prevent leukemia outgrowth. Moreover, in humans, only DC/TFA generated significant antileukemia CD4(+) and cytotoxic CD8(+) T cell responses in vitro. In summary, these data demonstrate that the choice of the acid elution procedure to isolate immunogenic peptides strongly influences the efficacy of the antileukemia immune responses. These finding raise essential considerations for the development of immunotherapeutic protocols for cancer patients. In our model, our results argue for the use of the TFA elution method to extract immunogenic AML-associated peptides.
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PMID:DC-based vaccine loaded with acid-eluted peptides in acute myeloid leukemia: the importance of choosing the best elution method. 1667 83

We evaluated efficacy and toxicity profiles of fludarabine, Ara-C, idarubicin, and G-CSF (Ida-FLAG) combination chemotherapy in 56 refractory and/or relapsed acute leukemia patients. Patients were treated with fludarabine phosphate 25 mg/m2/d (d1-5), Ara-C 2 g/m2/d (d1-5), idarubicin 12 mg/m2/d (d1-3), G-CSF was given subcutaneously from sixth day until absolute neutrophil count (ANC) >500/microL. One third of the acute myeloblastic leukemia (AML) and 45% of acute lymphoblastic leukemia (ALL) cases were primary refractory disease. In AML patients, complete remission (CR) was achieved in 15 cases (53.6%). One case showed partial remission (PR) (3.6%) and 12 cases (42.8%) had resistant to this regimen (RD). Grade IV hematologic toxicity occurred in all AML cases. Leukocyte recovery time was 16 days. Nonhematologic complications were mild to moderate nausea, vomiting, and mucositis and could be controlled by routine measures. Stem cell transplantation was performed in 5 patients and all achieved CR, 2 autologous and 3 allogeneic. In ALL patients, CR and PR were obtained in 8 (42.2%) and 2 (10.5%) of 22 cases; disease was resistant to Ida-FLAG in 9 (47.3%) cases. Grade IV hematologic toxicity occurred in all ALL cases. Leukocyte recovery time was 17 days. Nonhematologic toxicity consisted of nausea, vomiting, and mucositis and could be controlled by supportive therapy. Autologous transplantation was performed in 1 patient, but relapse disease occurred after 5 weeks. There was no correlation between response rate and leukemia subtype (AML versus ALL), leukocyte count, age, sex, disease status (de novo versus secondary), and RFS (early versus late relapse) (P > 0.05). Median survival was 16 weeks in all cases (22 weeks in AML versus 13 weeks). At present, only 3 patients are alive and 2 of these are in continuous remission. The rest of the patients died. In conclusion, Ida-FLAG is a good choice in cases with refractory/relapsing acute leukemia for salvage chemotherapy. High efficacy and a low-toxicity profile are preferable properties of this regimen, and this regimen has been found to be useful for cytoreduction, especially in candidates for allo-SCT.
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PMID:IDA-FLAG regimen for the therapy of primary refractory and relapse acute leukemia: a single-center experience. 1698 32

Tumor lysis syndrome is an oncologic emergency that is characterized by severe electrolyte abnormalities. The syndrome occurs in patients with lymphoproliferative malignancies, most often after chemotherapy, but also spontaneously. The pathophysiology involves tumor cell lysis resulting in the release of potassium, phosphate and uric acid. The deposition of uric acid and calcium phosphate crystals in the renal tubules may lead to acute renal failure. The treatment consists in hydration, correction of the acidosis and hyperkalemia, use of allopurinol and recombinant urate oxidase (rasburicase) for preventing urate nephropathy and haemodialysis. The authors report a case of a patient with acute myeloid leukemia, who developed severe tumor lysis syndrome after chemotherapy.
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PMID:[The pathophysiology, clinical signs and therapy of urate nephropathy]. 1743 51

Adhesion of leukemic cells to vascular cells may confer resistance to chemotherapeutic agents. We hypothesized that disruption of leukemic cell cytoskeletal stability and interference with vascular cell interactions would promote leukemic cell death. We demonstrate that low and nontoxic doses of microtubule-destabilizing agent combretastatin-A4-phosphate (CA4P) inhibit leukemic cell proliferation in vitro and induce mitotic arrest and cell death. Treatment of acute myeloid leukemias (AMLs) with CA4P leads to disruption of mitochondrial membrane potential, release of proapoptotic mitochondrial membrane proteins, and DNA fragmentation, resulting in cell death in part through a caspase-dependent manner. Furthermore, CA4P increases intracellular reactive oxygen species (ROS), and antioxidant treatment imparts partial protection from cell death, suggesting that ROS accumulation contributes to CA4P-induced cytotoxicity in AML. In vivo, CA4P inhibited proliferation and circulation of leukemic cells and diminished the extent of perivascular leukemic infiltrates, prolonging survival of mice that underwent xenotransplantation without inducing hematologic toxicity. CA4P decreases the interaction of leukemic cells with neovessels by down-regulating the expression of the adhesion molecule VCAM-1 thereby augmenting leukemic cell death. These data suggest that CA4P targets both circulating and vascular-adherent leukemic cells through mitochondrial damage and down-regulation of VCAM-1 without incurring hematologic toxicities. As such, CA4P provides for an effective means to treat refractory organ-infiltrating leukemias.
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PMID:The microtubule-targeting agent CA4P regresses leukemic xenografts by disrupting interaction with vascular cells and mitochondrial-dependent cell death. 1802 94


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