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: UMLS:C0023418 (leukemia)
93,477 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

One of the important approaches for further prolonging remission duration and eradicating minimal residual disease in acute leukemia is immunotherapy. Four kinds of immunotherapy for acute leukemia are under investigation: (1) monoclonal antibodies, among them, Mylotarg (cytotoxic antibiotic calicheamicin linked to CD33 Mab) is given for the treatment of refractory or relapsed acute myeloid leukemia and molecular relapse in acute promyelocytic leukemia with good results, Campath-1H (antiCD52 Mab) is administered in the treatment of prolymphocytic leukemia and Rituximab (anti-CD20 Mab) in B-PLL with high complete remission rates. Other Mabs under preclinical and clinical trials include anti-IL-2 receptor Mab for the treatment of acute T lymphocytic leukemia, anti-220 kD Mab-6G7 for acute leukemias, recombinant immune toxin BL22 (anti-CD22) for hairy cell leukemia and Mabs labeled with radio-isotopes for different types of acute leukemias; (2) adoptive cellular immunotherapy using cytokine-induced killer cell, alloreactive NK cells, allogeneic or autologous leukemic-specific CD8(+) cytotoxic T lymphocytes, and other immune effector cells; (3) cytokines and other immune modulators comprising IL-2, IL-12, GM-CSF, CD40L, FLT-3L and thalidomide and its derivatives; (4) leukemia vaccines of several different formulations including antigen-specific, leukemia cell-based, leukemia antigen-pulsed dendritic cell (DC) and leukemia-derived DC vaccines, the latter two formulations are more attractive. In conclusion, up to now, the most effective example of immunotherapy in acute leukemia is provided by the administration of Mabs, and the majority of other approaches in immunotherapy for acute leukemia although promising, need further studies.
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PMID:[Present status in studying immunotherapy for acute leukemia and its perspective--Editorial]. 1585 71

The hydroxamic acid (HAA) analogue pan-histone deacetylase (HDAC) inhibitors (HDIs) LAQ824 and LBH589 have been shown to induce acetylation and inhibit the ATP binding and chaperone function of heat shock protein (HSP) 90. This promotes the polyubiquitylation and degradation of the pro-growth and pro-survival client proteins Bcr-Abl, mutant FLT-3, c-Raf, and AKT in human leukemia cells. HDAC6 is a member of the class IIB HDACs. It is predominantly cytosolic, microtubule-associated alpha-tubulin deacetylase that is also known to promote aggresome inclusion of the misfolded polyubiquitylated proteins. Here we demonstrate that in the Bcr-abl oncogene expressing human leukemia K562 cells, HDAC6 can be co-immunoprecipitated with HSP90, and the knock-down of HDAC6 by its siRNA induced the acetylation of HSP90 and alpha-tubulin. Depletion of HDAC6 levels also inhibited the binding of HSP90 to ATP, reduced the chaperone association of HSP90 with its client proteins, e.g. Bcr-Abl, and induced polyubiquitylation and partial depletion of Bcr-Abl. Conversely, the ectopic overexpression of HDAC6 inhibited LAQ824-induced acetylation of HSP90 and alpha-tubulin and reduced LAQ824-mediated depletion of Bcr-Abl, AKT, and c-Raf. Collectively, these findings indicate that HDAC6 is also an HSP90 deacetylase. Targeted inhibition of HDAC6 leads to acetylation of HSP90 and disruption of its chaperone function, resulting in polyubiquitylation and depletion of pro-growth and pro-survival HSP90 client proteins including Bcr-Abl. Depletion of HDAC6 sensitized human leukemia cells to HAA-HDIs and proteasome inhibitors.
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PMID:Inhibition of histone deacetylase 6 acetylates and disrupts the chaperone function of heat shock protein 90: a novel basis for antileukemia activity of histone deacetylase inhibitors. 1593 40

Vascular endothelial growth factor (VEGF) and its associated molecule, placenta growth factor (PlGF) are now known to support normal hematopoiesis, and leukemia cell growth. In this study, expression of VEGF and PlGF in acute lymphoblastic leukemia (ALL) cells was examined by real time reverse transcription-polymerase chain reaction in 20 patient samples. Expression of PlGF was more intense in Philadelphia chromosome positive (Ph(+)) ALL than in Ph(-) ALL cases. On the other hand, expression level of VEGF was not different between Ph(+) and Ph(-) cases. Then, PlGF was added to the two ALL cell lines, CRL1929 (Ph(+)), and Nalm6 (Ph(-)). The PlGF stimulated the growth of CRL1929 in time- and dose-dependent manners, although the growth of Nalm6 was not affected by PlGF. The growth stimulation of CRL1929 by PlGF was confirmed by the increase of S phase cells. And the growth promoting effect of PlGF on CRL1929 was cancelled by simultaneous addition of VEGFR1/Fc (which binds to PlGF and abrogates its function), but was not cancelled by VEGFR2/Fc (which does not bind to PlGF). Then, addition of VEGFR1/Fc to the simple culture of CRL1929 demonstrated growth inhibitory effect. These observations demonstrated that PlGF stimulates the growth of Ph(+) ALL cells by both autocrine and paracrine pathways. Finally, PlGF-VEGFR1 loop might be a therapeutic target to improve the prognosis of Ph(+) ALL.
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PMID:Placenta growth factor stimulates the growth of Philadelphia chromosome positive acute lymphoblastic leukemia cells by both autocrine and paracrine pathways. 1614 32

The presence of persistent circulating leukemia cells, or engrafted into extramedullary tissues, is a bad prognostic factor for patients with acute leukemia. However, little is known about the mechanisms that regulate the exit of leukemia cells from the bone marrow (BM) microenvironment. We reveal that vascular endothelial growth factor receptor 1 (FLT-1) modulates acute leukemia distribution within the BM, along VEGF and PlGF gradients, regulating leukemia survival and exit into the peripheral circulation. FLT-1 activation on acute lymphoblastic leukemia (ALL) cells results in cell migration and proliferation in vitro, whereas in vivo FLT-1-overexpressing cells accumulate in the BM epiphysis of nonobese diabetic-severe combined immunodeficient (NOD-SCID) recipients and are detected in circulation 2 weeks after inoculation. In turn, FLT-1 neutralization affects leukemia localization (now in the BM diaphysis), increases leukemia apoptosis, and impedes the exit of ALL cells, prolonging the survival of inoculated mice. We demonstrate further that FLT-1-induced cell migration involves actin polymerization and lipid raft formation. Taken together, we show that FLT-1 regulates the BM localization of ALL cells, determining their survival and exit into the circulation and ultimately the survival of inoculated recipients. FLT-1 targeting on subsets of acute leukemias may delay the onset of extramedullary disease, which may be advantageous in combinatorial therapeutic settings.
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PMID:VEGFR-1 (FLT-1) activation modulates acute lymphoblastic leukemia localization and survival within the bone marrow, determining the onset of extramedullary disease. 1624 83

PTK787/ZK 222584 (PTK/ZK) is an oral angiogenesis inhibitor targeting vascular endothelial growth factor (VEGF) receptor tyrosine kinases, including VEGFR-1/Flt-1, VEGFR-2/KDR, VEGFR-3/Flt-4, the platelet-derived growth factor receptor tyrosine kinase and the c-kit protein tyrosine kinase. The objective of this Phase I study was to evaluate the safety, tolerability, biologic activity and pharmacologic profile of PTK/ZK administered orally, twice daily, on a continuous dosing schedule in patients with primary refractory or relapsed acute myeloid leukemia (AML), secondary AML, poor-prognosis de novo AML or advanced myelodysplastic syndrome (MDS). Acute myeloid leukemia patients for whom PTK/ZK monotherapy was ineffective could receive PTK/ZK combined with standard induction chemotherapy. Sixty-three patients received PTK/ZK at doses of 500-1000 mg orally b.i.d. Safety and pharmacokinetic data were collected. Responses were evaluated according to standard bone marrow and peripheral blood criteria. At 1000 mg b.i.d., dose-limiting toxicities of lethargy, hypertension, nausea, emesis and anorexia were observed. Other adverse events related to PTK/ZK were dizziness, weakness, fatigue, diarrhea and pruritus; these were generally mild and reversible. Pharmacokinetic data showed that steady state was reached by day 14, there was no accumulation with repeat dosing and there was no significant increase in exposure at steady state beyond the maximum tolerated dose (MTD). Complete remission was observed in five of 17 AML patients treated with PTK/ZK combined with chemotherapy. In conclusion, the MTD of PTK/ZK is 750 mg orally b.i.d. The drug is generally well tolerated and can be given in combination with chemotherapy for patients with MDS and AML.
Leukemia 2006 Jun
PMID:Phase 1 study of PTK787/ZK 222584, a small molecule tyrosine kinase receptor inhibitor, for the treatment of acute myeloid leukemia and myelodysplastic syndrome. 1661 23

Vascular endothelial growth factor (VEGF) and VEGF receptor-1 (VEGFR-1/Flt-1) were shown to be involved in pathological angiogenesis, particularly rheumatoid arthritis (RA). However, the molecular basis of their actions is not fully understood. Here we report that in a murine model of RA, deletion of the tyrosine kinase (TK) domain of VEGFR-1 decreased the incidence and clinical symptoms of RA. Pathological symptoms, such as synovial hyperplasia, inflammatory infiltrates, pannus formation, and cartilage/bone destruction, became milder in Vegfr-1 tk(-/-) mice compared with wild-type (Wt) mice in the human T-cell leukemia virus-1 (HTLV-1) pX-induced chronic models. VEGFR-1 TK-deficient bone marrow cells showed a suppression of multilineage colony formation. Furthermore, macrophages induced to differentiate in vitro showed a decrease in immunologic reactions such as phagocytosis and the secretion of interleukin-6 (IL-6) and VEGF-A. Treatment of this RA model with a small molecule inhibitor for VEGFR TK, KRN951, also attenuated the arthritis. These results indicate that the VEGFR-1 TK signaling modulates the proliferation of bone marrow hematopoietic cells and immunity of monocytes/macrophages and promotes chronic inflammation, which may be a new target in the treatment of RA.
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PMID:Signaling of vascular endothelial growth factor receptor-1 tyrosine kinase promotes rheumatoid arthritis through activation of monocytes/macrophages. 1670 27

We studied antitumor effects of receptor tyrosine kinase inhibitor sunitinib (formerly SU11248) against a variety of hematologic malignancies including the following leukemias: eosinophilic (EOL-1), acute myeloid (THP-1, U937, Kasumi-1), biphenotypic (MV4-11), acute lymphoblastic (NALL-1, Jurkat, BALL-2, PALL-1, PALL-2), blast crisis of chronic myeloid (KU812, Kcl-22, K562), and adult T-cell (MT-1, MT-2, MT-4), as well as non-Hodgkin's lymphoma (KS-1, Dauji, Akata) and multiple myeloma (U266). Thymidine uptake studies showed that sunitinib was active against EOL-1, MV4-11, and Kasumi-1 cells, which possessed activating mutations of the PDGFRalpha, FLT-3, and c-KIT genes, respectively, with IC(50)s of <30 nmol/L. In addition, sunitinib inhibited the proliferation of freshly isolated leukemia cells from patients possessing mutations in FLT3 gene. Annexin V staining showed that sunitinib induced apoptosis of these cells. Sunitinib inhibited phosphorylation of FLT3 and PDGFRalpha in conjunction with blockade of mammalian target of rapamycin signaling in MV4-11 and EOL-1 cells, respectively. Interestingly, rapamycin analogue RAD001 enhanced the ability of sunitinib to inhibit the proliferation of leukemia cells and down-regulate levels of mammalian target of rapamycin effectors p70 S6 kinase and eukaryotic initiation factor 4E-binding protein 1 in these cells. Taken together, sunitinib may be useful for treatment of individuals with leukemias possessing activation mutation of tyrosine kinase, and the combination of sunitinib and RAD001 represents a promising novel treatment strategy.
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PMID:The antitumor effects of sunitinib (formerly SU11248) against a variety of human hematologic malignancies: enhancement of growth inhibition via inhibition of mammalian target of rapamycin signaling. 1704 Oct 96

In acute myeloid leukemia (AML), autocrine or paracrine activation of receptor tyrosine kinases such as c-kit and FLT3 contributes to proliferation and apoptosis resistance of leukemic blasts. This provided the rationale for a multicenter clinical trial in patients with refractory AML with SU5416, a small molecule kinase inhibitor which blocks phosphorylation of c-kit, FLT3, VEGFR-1, VEGFR-2 (KDR) and VEGFR-3. The levels of VEGF mRNA expression were investigated in peripheral blood leukemic blasts taken from AML patients before and during treatment with SU5416. Rapid down regulation of VEGF was observed in AML blasts from 72% (13 of 18) of patients analysed. Patients initially expressing high VEGF-levels had a stronger downregulation and a higher clinical response rate (mean 865-fold, n = 10, P = 0,01) than patients initially expressing low VEGF-levels (mean four-fold, n = 8). These results suggest that abnormal high VEGF expression is downregulated by SU5416 treatment, and furthermore that decreases in VEGF mRNA levels may provide an early marker of therapeutic response with anti-angiogenic therapy. Additionally, protein expression of STAT5 and AKT was assessed by western blotting in these patient samples, as well as in the leukemia cell line, M-07e, treated in vitro with SU5416 as a model system. In the AML patient samples, parallel downregulation of both STAT5 and AKT was observed in several cases (STAT5 in four of 15; AKT in three of six examined patients). These effects were confirmed with the cell line M-07e after incubation with SU5416 in vitro using concentrations that are achievable in patients. In summary, our data show suppression of the expression of VEGF and key signal transduction intermediates in AML blasts during treatment with SU5416.
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PMID:Downregulation of VEGF-A, STAT5 and AKT in acute myeloid leukemia blasts of patients treated with SU5416. 1716 5

The annual incident rate of pediatric acute myeloid leukemia (AML) is now 10 per million in Japan, against 5 to 9 per million in the USA and Europe. Overall long-term survival has now been achieved for more than 50% of pediatric patients with AML in the USA and in Europe. The prognostic factors of pediatric AML were analyzed,and patients with AML were classified according to prognostic factors. The t(15;17), inv(16) and t(8;21) have emerged as predictors of good prognosis in children with AML. Monosomy 7, monosomy 5 and del (5 q) abnormalities showed a poor prognosis. In addition to chromosomal deletions, FLT 3/ITD identifies pediatric patients with a particularly poor prognosis. Clinical trials of AML feature intensive chemotherapy with or without subsequent stem cell transplantation. Risk group stratification is becoming increasingly important in planning AML therapy. APL can be distinguished from other subtypes of AML by virtue of its excellent response and overall outcome as a result of differentiation therapy with ATRA. Children with Down syndrome and AML have been shown to have a superior prognosis to AML therapy compared to other children with AML. The results of the Japan Cooperative Study Group protocol ANLL 91 was one of the best previously reported in the literature. With the consideration of quality of life (QOL), risk-adapted therapy was introduced in the AML 99 trial conducted by the Japanese Childhood AML Cooperative Study Group. A high survival rate of 79% at 3 years was achieved for childhood de novo AML in the AML 99 trial. To evaluate the efficacy and safety of the treatment strategy according to risk stratification based on leukemia cell biology and response to the initial induction therapy in children with AML, the Japanese Pediatric Leukemia/Lymphoma Study Group (JPLSG) has organized multi-center phase II trials in children with newly diagnosed AML.
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PMID:[Acute myeloid leukemia]. 1730 20

Leukemia cell motility and transendothelial migration into extramedullary sites are regulated by angiogenic factors and are considered unfavorable prognostic factors in acute leukemias. We have studied cross talk among (1) the vascular endothelial growth factor receptor-1, FLT-1; (2) the human eag-related gene 1 (hERG1) K(+) channels; and (3) integrin receptors in acute myeloid leukemia (AML) cells. FLT-1, hERG1, and the beta(1) integrin were found to form a macromolecular signaling complex. The latter mostly recruited the hERG1B isoform of hERG1 channels, and its assembly was necessary for FLT-1 signaling activation and AML cell migration. Both effects were inhibited when hERG1 channels were specifically blocked. A FLT-1/hERG1/beta(1) complex was also observed in primary AML blasts, obtained from a population of human patients. The co-expression of FLT-1 and hERG1 conferred a pro-migratory phenotype to AML blasts. Such a phenotype was also observed in vivo. The hERG1-positive blasts were more efficient in invading the peripheral circulation and the extramedullary sites after engraftment into immunodeficient mice. Moreover, hERG1 expression in leukemia patients correlated with a higher probability of relapse and shorter survival periods. We conclude that in AML, hERG1 channels mediate the FLT-1-dependent cell migration and invasion, and hence confer a greater malignancy.
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PMID:VEGFR-1 (FLT-1), beta1 integrin, and hERG K+ channel for a macromolecular signaling complex in acute myeloid leukemia: role in cell migration and clinical outcome. 1742 Feb 87


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