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)

The study on biological effects of SDF-1/CXCR4 axis composed of stromal cell derived factor-1 (SDF-1) and its receptor CXCR4 is progressing rapidly in the recent years. The SDF-1/CXCR4 axis plays an important role in occurrence and development of tumors and closely correlate with angiogenesis of tumors. This review focuses the progress of study on SDF-1/CXCR4 axis and angiogenesis in leukemia including SDF-1/ and its receptor CXCR4, the expression of SDF-1/CXCR4 axis in leukemic cells, the mechanism of relation between SDF-1/CXCR4 axis and angiogenesis in leukemia, the application of inhibitors against SDF-1/CXCR4 in treatment of angiogenesis and so on.
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PMID:[Advance of research on SDF-1/CXCR4 axis and angiogenesis in leukemia--review]. 1842 84

The chemokine stromal cell-derived factor-1 (SDF-1) and its receptor, CXCR4, participate in the retention of acute myeloblastic leukemia (AML) cells within the bone marrow microenvironment and their release into the circulation. AML cells also constitutively express SDF-1-dependent elastase, which regulates their migration and proliferation. To study the molecular events and genes regulated by the SDF-1/CXCR4 axis and elastase in AML cells, we examined gene expression profiles of the AML cell line, U937, under treatment with a neutralizing anti-CXCR4 antibody or elastase inhibitor, as compared with non-treated cells, using DNA microarray technology. Unsupervised hierarchical clustering analysis demonstrated similar gene expression profiles of anti-CXCR4 antibody or elastase inhibitor-treated cells, as compared with control. Pathway and functional analysis showed a greater tendency toward differentiation in cells under either one of both treatment modalities. Thus given, we further analyzed the effects of CXCR4 inhibition on AML cell growth and differentiation using the antagonist AMD3100. AMD3100 arrested proliferation in AML cell lines and triggered changes that mimicked differentiation, including morphological changes and the expression of myeloid differentiation antigens. Inhibition of elastase also triggered the differentiation of AML cells. Our study defines a new role for the SDF-1/CXCR4 axis in the regulation of leukemic cell survival and differentiation.
Leukemia 2008 Dec
PMID:The CXCR4 antagonist AMD3100 impairs survival of human AML cells and induces their differentiation. 1876 46

It has previously been demonstrated that there are two distinct mechanisms for genetic resistance to human immunodeficiency virus type 1 (HIV-1) conferred by the CCR5Delta32 gene: the loss of wild-type CCR5 surface expression and the generation of CCR5Delta32 protein, which interacts with CXCR4. To analyse the protective effects of long-term expression of the CCR5Delta32 protein, recombinant lentiviral vectors were used to deliver the CCR5Delta32 gene into human cell lines and primary peripheral blood mononuclear cells that had been immortalized by human T-cell leukemia virus type 1. Blasticidin S-resistant cell lines expressing the lentivirus-encoded CCR5Delta32 showed a significant reduction in HIV-1 Env-mediated fusion assays. It was shown that CD4(+) T lymphocytes expressing the lentivirus-encoded CCR5Delta32 gene were highly resistant to infection by a primary but not by a laboratory-adapted X4 strain, suggesting different infectivity requirements. In contrast to previous studies that analysed the CCR5Delta32 protective effects in a transient expression system, this study showed that long-term expression of CCR5Delta32 conferred resistance to HIV-1 despite cell-surface expression of the HIV co-receptors. The results suggest an additional unknown mechanism for generating the CCR5Delta32 resistance phenotype and support the hypothesis that the CCR5Delta32 protein acts as an HIV-suppressive factor by altering the stoichiometry of the molecules involved in HIV-1 entry. The lentiviral-CCR5Delta32 vectors offer a method of generating HIV-resistant cells by delivery of the CCR5Delta32 gene that may be useful for stem cell- or T-cell-based gene therapy for HIV-1 infection.
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PMID:Resistance to human immunodeficiency virus type 1 (HIV-1) generated by lentivirus vector-mediated delivery of the CCR5{Delta}32 gene despite detectable expression of the HIV-1 co-receptors. 1879 31

Berberine plays a prominent role on the control of tumor cell invasion and migration. SDF-1 is a homeostatic chemokine that signals through CXCR4 which is expressed by hematopoietic tumor cells. The SDF-1/CXCR4 axis is involved in the migration process of leukemic cells. In this study, we investigated the effects of berberine on the SDF-1-induced HL-60 cells, primary acute myeloid leukemia (AML) cells and leukemic stem cells (LSCs) migration. Transwell migration chambers (8 microm) were used to assess the role of berberine on leukemic cell migration; Flow cytometry was used to analyze the role of berberine on the CXCR4 expression; SDF-1 protein level secreted by bone marrow stromal cells (BMSCs) was evaluated by ELISA. Results demonstrated that berberine could partly inhibit SDF-1-induced AML cells as well as LSCs migration. Berberine could reduce SDF-1 protein level secreted by BMSCs in the microenvironment but not affect CXCR4 expression on HL-60 cell membrane, and we hypothesized that berberine could inhibit AML cells migration partly by reducing the secreting of SDF-1 by BMSCs and inhibiting HERG1 K(+) channels of leukemic cells. Therefore, it is speculated that berberine might be a potentially effective agent for prevention of leukemia.
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PMID:Berberine inhibits SDF-1-induced AML cells and leukemic stem cells migration via regulation of SDF-1 level in bone marrow stromal cells. 1880 69

SDF-1alpha/CXCR4 signaling plays a key role in leukemia/bone marrow microenvironment interactions. We previously reported that bone marrow-derived stromal cells inhibit chemotherapy-induced apoptosis in acute myeloid leukemia (AML). Here we demonstrate that the CXCR4 inhibitor AMD3465 antagonized stromal-derived factor 1alpha (SDF-1alpha)-induced and stroma-induced chemotaxis and inhibited SDF-1alpha-induced activation of prosurvival signaling pathways in leukemic cells. Further, CXCR4 inhibition partially abrogated the protective effects of stromal cells on chemotherapy-induced apoptosis in AML cells. Fetal liver tyrosine kinase-3 (FLT3) gene mutations activate CXCR4 signaling, and coculture with stromal cells significantly diminished antileukemia effects of FLT3 inhibitors in cells with mutated FLT3. Notably, CXCR4 inhibition increased the sensitivity of FLT3-mutated leukemic cells to the apoptogenic effects of the FLT3 inhibitor sorafenib. In vivo studies demonstrated that AMD3465, alone or in combination with granulocyte colony-stimulating factor, induced mobilization of AML cells and progenitor cells into circulation and enhanced antileukemic effects of chemotherapy and sorafenib, resulting in markedly reduced leukemia burden and prolonged survival of the animals. These findings indicate that SDF-1alpha/CXCR4 interactions contribute to the resistance of leukemic cells to signal transduction inhibitor- and chemotherapy-induced apoptosis in systems mimicking the physiologic microenvironment. Disruption of these interactions with CXCR4 inhibitors represents a novel strategy of sensitizing leukemic cells by targeting their protective bone marrow microenvironment.
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PMID:Targeting the leukemia microenvironment by CXCR4 inhibition overcomes resistance to kinase inhibitors and chemotherapy in AML. 1952 Aug 13

The CXCR4/SDF-1 axis has been studied extensively because of its role in development and hematopoiesis. In acute myeloid leukemia (AML), elevated expression of CXCR4 has been shown to correlate with shortened survival. Hy-poxia increases CXCR4 in several tumor models, but the impact of reduced O(2) partial pressure (pO(2)) on expression and biologic function of CXCR4 in AML is unknown. We determined pO(2) in bone marrows of AML patients as 6.1% (+/-1.7%). At this pO(2), CXCR4 surface and total expression were up-regulated within 10 hours in leukemic cell lines and patient samples as shown by Western blotting, fluorescence-activated cell sorting, and microscopy. Interestingly, hypoxic cells failed to internalize CXCR4 in response to SDF-1, and upon reoxygenation at 21% O(2), surface and total expression of CXCR4 rapidly decreased independent of adenosine triphosphate or proteasome activity. Instead, increased pO(2) led to alteration of lipid rafts by cholesterol depletion and structural changes and was associated with increased shedding of CXCR4-positive microparticles, suggesting a novel mechanism of CXCR4 regulation. Given the importance of CXCR4 in cell signaling, survival, and adhesion in leukemia, the results suggest that pO(2) be considered a critical variable in conducting and interpreting studies of CXCR4 expression and regulation in leukemias.
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PMID:CXCR4 expression and biologic activity in acute myeloid leukemia are dependent on oxygen partial pressure. 1895 86

Hematopoietic and epithelial cancer cells express CXCR4, a seven-transmembrane G-protein-coupled chemokine receptor. Stromal cells within the bone marrow microenvironment constitutively secrete stromal cell-derived factor-1 (SDF-1/CXCL12), the ligand for CXCR4. Activation of CXCR4 induces leukemia cell trafficking and homing to the marrow microenvironment, where CXCL12 retains leukemia cells in close contact with marrow stromal cells that provide growth and drug resistance signals. CXCR4 antagonists, such as Plerixafor (AMD3100) and T140 analogs, can disrupt adhesive tumor-stroma interactions and mobilize leukemia cells from their protective stromal microenvironment, making them more accessible to conventional drugs. Therefore, targeting the CXCR4-CXCL12 axis is a novel, attractive therapeutic approach that is explored in ongoing clinical trials in leukemia patients. Initially, CXCR4 antagonists were developed for the treatment of HIV, where CXCR4 functions as a co-receptor for virus entry into T cells. Subsequently, CXCR4 antagonists were noticed to induce leukocytosis, and are currently used clinically for mobilization of hematopoietic stem cells. However, because CXCR4 plays a key role in cross-talk between leukemia cells (and a variety of other tumor cells) and their microenvironment, cancer treatment may become the ultimate application of CXCR4 antagonists. Here, we summarize the development of CXCR4 antagonists and their preclinical and clinical activities, focusing on leukemia and other cancers.
Leukemia 2009 Jan
PMID:CXCR4 antagonists: targeting the microenvironment in leukemia and other cancers. 1898 63

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

Normal T cells can mediate antileukemic reactivity after allogeneic stem cell transplantation and T cell targeting immunotherapy is now considered for patients receiving conventional chemotherapy. This antileukemic reactivity is most effective in patients with a low leukemia cell burden, and this burden is expected to be lowest early after transplantation/chemotherapy when patients are cytopenic. Local T cell recruitment will then be essential for the efficiency of the antileukemic response. In this context, the authors compared the chemokine receptor expression for T cells derived from healthy individuals and acute myelogenous leukemia patients with therapy-induced cytopenia after conventional chemotherapy or allogeneic stem cell transplantation. Circulating CD3(+) T cells showed the same chemokine receptor expression for all three groups: CCR1(low), CCR2(low), CCR3(low), CCR4(intermediate), CCR5(intermediate), CCR7(low/intermediate), CXCR2(low), CXCR3(intermediate), and CXCR4(high). Thus, only minor differences between the groups were observed when comparing individual receptors, and we therefore conclude that the chemokine receptor profiles of circulating CD3(+) T cells show no qualitative and only minor quantitative differences for these three groups.
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PMID:Circulating T cells derived from acute leukemia patients with severe therapy-induced cytopenia express a wide range of chemokine receptors. 1905 60


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