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)

CD4(+)CD25(+)FOXP3(+) T regulatory cells (T(regs)) prevent autoimmunity by restricting overexuberant immune responses, but the same subpopulation can incur detrimental effects on antitumor responses. In both cases, the suppressor potential of T(regs) appears to be strongly influenced by their compartmentalization. In myelodysplastic syndromes (MDS), immune deregulation and autoimmunity in the early stages might lead to ineffective hematopoiesis and bone marrow (BM) failure, whereas late-stage disease is characterized by the immune escape of the malignant clone. We show that these two stages of MDS are associated with differential T(reg) activity. Specifically, we found that in early stage MDS, compared with normal hematopoiesis and late stage MDS, T(regs) are dysfunctional and their BM homing through the CXCL12/CXCR4 axis is seriously impaired as a result of CXCR4 downregulation. Conversely, in late stage MDS, T(regs) are systemically and locally expanded and retain their function and migratory capacity. Moreover, T(reg) levels follow the disease course and are significantly reduced in treatment responding patients. Our findings indicate T(reg) involvement in the pathophysiology of MDS; defective suppressor function and BM trafficking of T(regs) may be important in the autoimmune process of early MDS, but increased T(reg) activity could favor leukemic clone progression in late stage disease.
Leukemia 2009 Mar
PMID:Kinetics, function and bone marrow trafficking of CD4+CD25+FOXP3+ regulatory T cells in myelodysplastic syndromes (MDS). 1902 May 38

The CXCR4-SDF-1 axis plays a central role in the trafficking and retention of normal and malignant stem cells in the bone marrow (BM) microenvironment. Here, we used a mouse model of acute promyelocytic leukemia (APL) and a small molecule competitive antagonist of CXCR4, AMD3100, to examine the interaction of mouse APL cells with the BM microenvironment. APL cells from a murine cathepsin G-PML-RARalpha knockin mouse were genetically modified with firefly luciferase (APL(luc)) to allow tracking by bioluminescence imaging. Coculture of APL(luc) cells with M2-10B4 stromal cells protected the leukemia cells from chemotherapy-induced apoptosis in vitro. Upon injection into syngeneic recipients, APL(luc) cells rapidly migrated to the BM followed by egress to the spleen then to the peripheral blood with death due to leukostasis by day 15. Administration of AMD3100 to leukemic mice induced a 1.6-fold increase in total leukocytes and a 9-fold increase of circulating APL blast counts, which peak at 3 hours and return to baseline by 12 hours. Treatment of leukemic mice with chemotherapy plus AMD3100 resulted in decreased tumor burden and improved overall survival compared with mice treated with chemotherapy alone. These studies provide a proof-of-principle for directing therapy to the critical tethers that promote AML-niche interactions.
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PMID:Chemosensitization of acute myeloid leukemia (AML) following mobilization by the CXCR4 antagonist AMD3100. 1962 18

A number of molecular targets have been identified in leukemia, based on the understanding of signaling pathways controlling cell differentiation, proliferation, apoptosis, and malignant transformation. Growth factors and integrins interact with their receptors and activate signaling cascades with intimate interconnections. The specific niches within the bone marrow microenvironment may provide a sanctuary for subpopulations of leukemic cells to escape chemotherapy-induced death and acquire drug resistance. Investigations into bone marrow stroma-leukemia crosstalk may result in the development of strategies against the acquisition of a chemo-resistant phenotype and enhance the efficacy of therapies in leukemia. In recent studies, we proposed novel therapeutic interventions targeting the microenvironment/leukemia interaction focusing on SDF1/CXCR4, ILK/PI3K/Akt, TGF-beta, and Notch signaling. Gene transcriptional activity is regulated by chromatin modification and DNA methylation. Nuclear receptors such as RAR, RXR, and PPARgamma exert histone acetyl transferase activity (HAT). The transcription of target genes is initiated following the ligation of these receptors, recruitment of co-activators, and replacement of repressors. We demonstrated that histone acetylation by the PPARgamma agonist CDDO, RAR/RXR agonist ATRA, and/or histone deacetylase inhibitors (HDACIs) reversed the silenced RARbeta and MDR1 genes in acute promyelocytic leukemia, and that HDACI induced apoptosis with phagocytosis through the induction of Annexin A1 in AML1/ETO-positive acute myelocytic leukemia (AML) cells. The translation of research findings into effective clinical laboratory tests is an important approach. The flow cytometric technique is a powerful tool in the field of clinical laboratory medicine, with its accurate and rapid analysis. We carried out phospho-specific flow cytometry to investigate protein phosphorylation in AML cells and detect ZAP-70 in chronic lymphocytic leukemia cells, including the evaluation of antibodies, staining epitopes, fixing and permeabilizing methods, and analyzing systems. Finally, we emphasize the potential applications of research findings and methods in the fields of clinical medicine, molecular diagnosis, and targeting therapy.
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PMID:[Molecular diagnosis of and molecular targeting therapy for leukemia]. 1931 19

The mechanisms regulating the migration of leukaemic cells between the blood and bone marrow compartments remain obscure, but are of fundamental importance for the dissemination of the disease. This study investigated the in vivo homing of human B cell progenitor acute lymphoblastic leukaemia (ALL) cells to the femoral bone marrow of non-obese diabetic severe combined immunodeficient (NOD/SCID) mice. It was demonstrated that patient ALL cells use the chemokine axis, chemokine (CXC motif) receptor 4 (CXCR4)/ chemokine (CXC motif) ligand 12 (CXCL12), to home to the femoral marrow. CXCL12-mediated signalling through p38 mitogen-activated protein kinase (MAPK) was required for optimal homing. In contrast, the homing of normal peripheral blood CD34(+) cells and the cytokine-dependent CD34(+) cell line Mo7e was independent of p38MAPK, consistent with the dependence of these cells, as well as normal CD34(+) CD19(+) B cell progenitors, on PI-3K/AKT signalling. Altogether, our data provide clarification of the direct role of CXCL12 in the bone marrow homing of ALL cells and demonstrate unique signalling molecule usage that may have therapeutic implications for this disease.
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PMID:CXCR4 mediates the homing of B cell progenitor acute lymphoblastic leukaemia cells to the bone marrow via activation of p38MAPK. 1934 5

Despite Imatinib's remarkable success in chronic myelogenous leukemia treatment, monotherapy frequently causes resistance, underlining the rationale for combination chemotherapy. A potential approach would be interrupting the SDF-1/CXCR4 axis using the selective CXCR4 antagonist Plerixafor (previously AMD3100), as this axis has been reported to provide survival-enhancing effects to myeloid progenitor cells. By efficient CXCR4 blocking in the CXCR4(+)/BCR-ABL(+) cell line BV-173, plerixafor (1-100 muM) significantly inhibits SDF-1alpha-mediated chemotaxis and cell migration toward the murine stroma cell line FBMD-1. Furthermore, plerixafor also significantly (10-100 muM) increased the detachment rate of SDF-1-mediated/VCAM-1-associated cell adherence under shear stress. Using a stroma-dependent coculture assay, plerixafor sensitized BCR-ABL(+) cells toward tyrosine kinase inhibitor therapy. Because the level of cell killing nearly reached that of samples cultured without stroma, a cell-cell interaction disruption seems to improve the efficacy of BCR-ABL-targeting drugs. In addition, we could show that exposure of BCR-ABL(+) cells to Imatinib or Nilotinib induced an increase in surface CXCR4 expression. Our data suggest that for BCR-ABL(+) leukemia, the selective blocking of the SDF-1/CXCR4 axis by plerixafor is a potential mechanism to overcome the protective effect of the bone marrow environment, thereby increasing the therapeutic potency of anti-BCR-ABL drugs and the therapeutic window.
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PMID:Plerixafor inhibits chemotaxis toward SDF-1 and CXCR4-mediated stroma contact in a dose-dependent manner resulting in increased susceptibility of BCR-ABL+ cell to Imatinib and Nilotinib. 1975 19

Megakaryoblastic leukemia 1 (MAL) is a transcriptional coactivator of serum response factor (SRF). In acute megakaryoblastic leukemia, the MAL gene is translocated and fused with the gene encoding one twenty-two (OTT). Herein, we show that MAL expression increases during the late differentiation steps of neonate and adult human megakaryopoiesis and localized into the nucleus after Rho GTPase activation by adhesion on collagen I or convulxin. MAL knockdown in megakaryocyte progenitors reduced the percentage of cells forming filopodia, lamellipodia, and stress fibers after adhesion on the same substrates, and reduced proplatelet formation. MAL repression led to dysmorphic megakaryocytes with disorganized demarcation membranes and alpha granules heterogeneously scattered in the cytoplasm. Gene expression profiling revealed a marked decrease in metalloproteinase 9 (MMP-9) and MYL9 expression after MAL inhibition. Luciferase assays in HEK293T cells and chromatin immunoprecipitation in primary megakaryocytes showed that the MAL/SRF complex directly regulates MYL9 and MMP9 in vitro. Megakaryocyte migration in response to stromal cell-derived factor 1, through Matrigel was considerably decreased after MAL knockdown, implicating MMP9 in migration. Finally, the use of a shRNA to decrease MYL9 expression showed that MYL9 was involved in proplatelet formation. MAL/SRF complex is thus involved in platelet formation and megakaryocyte migration by regulating MYL9 and MMP9.
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PMID:MAL/SRF complex is involved in platelet formation and megakaryocyte migration by regulating MYL9 (MLC2) and MMP9. 1989 23

Tumor microenvironment has a major role in cancer progression and resistance to treatment. The bone marrow (BM) is a dynamic network of growth factors, cytokines and stromal cells, providing a permissive environment for leukemogenesis and progression. Both BM stroma and leukemic blasts promote angiogenesis, which is increased in acute lymphoblastic leukemia and acute myeloid leukemia. Growth factors like vascular endothelial growth factor (VEGF), basic fibroblast growth factor and angiopoietins are the main proangiogenic mediators in acute leukemia. Autocrine proleukemic loops have been described for VEGF and angiopoietin in hematopoietic cells. Interactions of stromal cells and extracellular matrix with leukemic blasts can also generate antiapoptotic signals that contribute to neoplastic progression and persistence of treatment-resistant minimal residual disease. High expression of CXC chemokine ligand 4 (CXCR4) by leukemic blasts and activation of the CXCR4-CXCL12 axis is involved in leukemia progression and disruption of normal hematopoiesis. Leukemia-associated bone microenvironment markers could be used as prognostic or predictive indicators of disease progression and/or treatment outcome. Studies related to bone microenvironment would likely provide a better understanding of the treatment resistance associated with leukemia therapy and design of new treatments.
Leukemia 2009 Dec
PMID:Contribution of bone microenvironment to leukemogenesis and leukemia progression. 1972 27

As the induction of contact hypersensitivity is the result of a series of cellular processes, including maturation and migration of epidermal dendritic cells (Langerhans cells (LC)), a battery of assays based on these in vivo events might provide a robust in vitro predictability model for distinguishing sensitizers from non-sensitizers. Therefore, assays with read-out for changes in CD86 expression and CXCL8 secretion were compared with a novel functional assay based on the in vitro migratory behaviour of LC. In all three assays LC derived from the human myeloid-leukaemia-cell-line MUTZ-3 (MUTZ-LC) were used. Exposure of MUTZ-LC to a panel of five sensitizers and three non-sensitizers resulted in increased CD86 expression in only 3/5 sensitizers, but also in 1/3 non-sensitizers. In contrast, CXCL8 secretion was uniformly increased after exposure to all sensitizers, but not after exposure to non-sensitizers. In a transwell migration assay, preferential migration of sensitizer-exposed MUTZ-LC towards CXCL12 was observed (5/5 sensitizers), whereas non-sensitizer-exposed MUTZ-LC only migrated towards CCL5 (3/3 non-sensitizers). In conclusion, the novel MUTZ-LC migration assay and analysis of CXCL8 secretion proved to be more successful than analysis of CD86 in predicting sensitizers from non-sensitizers and therefore warrant further investigation in the field of in vitro assay development.
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PMID:Comparison of a novel CXCL12/CCL5 dependent migration assay with CXCL8 secretion and CD86 expression for distinguishing sensitizers from non-sensitizers using MUTZ-3 Langerhans cells. 1987 16

Disseminated Mycobacterium avium complex (MAC) infection is a rare but severe disease mostly seen in patients with AIDS. It has been previously described in patients suffering from other kinds of immunodeficiency (e.g. primary immunodeficiency diseases in children or hairy cell leukaemia). We report two cases of disseminated MAC disease in young women with extended granulomatosis that revealed a new form of severe immunodeficiency syndrome. Both clinical observations initially appeared to be very similar to WHIM syndrome (Warts, Hypogammaglobulinemia, Infection, Myelokathexis), a rare immunodeficiency disease correlated with CXC chemokine receptor 4 (CXCR4) mutation leading to an impaired internalization of the receptor upon its ligand CXCL12. We investigated the CXCR4 status of the lymphocytes in both patients and found a severe defect in CXCL12-promoted internalization but no mutation of its gene. Moreover, myelokathexis was not noted in bone marrow biopsies and therefore a diagnosis of WHIM syndrome could not be assessed. This immunodeficiency syndrome associated with CXCR4 dysfunction was responsible for severe MAC infection in our patients, with a fatal outcome in one case. It may be possible that these patients would have benefited from early antimycobacterial infection or azythromycin prophylaxis.
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PMID:Two cases of disseminated Mycobacterium avium infection associated with a new immunodeficiency syndrome related to CXCR4 dysfunctions. 2014 20

Homing of chronic lymphocytic leukemia (CLL) cells to sites favoring growth, a critical step in disease progression, is principally coordinated by the CXCL12/CXCR4 axis. A cohort of 62 CLL patients was divided into migrating and nonmigrating subsets according to chemotaxis toward CXCL12. Migrating patients phosphorylated extracellular signal-regulated kinase 1/2 (ERK1/2) proteins more than nonmigrating patients (P<0.0002). CD38 expression was the parameter most strongly associated with heightened CXCL12 signaling (P<0.0001), confirmed by independent statistical approaches. Consistent with this observation, CD38(-) CLL cells in samples with bimodal CD38 expression responded less to CXCL12 than the intact clone (P=0.003). Furthermore, lentivirus-induced de novo expression of CD38 was paralleled by increased responses to CXCL12, as compared with cells infected with a control virus. CD38 ligation with agonistic monoclonal antibodies (mAbs) enhanced CXCL12 signaling, whereas blocking anti-CD38 mAbs inhibited chemokine effects in vitro. This is attributed to physical proximity on the membrane between CD38 and CXCR4 (the CXCL12 receptor), as shown by (i) coimmunoprecipitation and (ii) confocal microscopy experiments. Blocking anti-CD38 mAbs significantly compromised homing of CLL cells from blood to lymphoid organs in a mouse model. These results indicate that CD38 synergizes with the CXCR4 pathway and support the working hypothesis that migration is a central step in disease progression.
Leukemia 2010 May
PMID:CD38 increases CXCL12-mediated signals and homing of chronic lymphocytic leukemia cells. 2022 Jul 74


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