SDF-1alpha/CXCL12 enhances retroviral-mediated gene transfer into immature subsets of human and murine hematopoietic progenitor cells.

Genetic modification of hematopoietic stem and progenitor cells has the potential to treat diseases affecting blood cells. Oncoretroviral vectors have been used for gene therapy; however, clinical success has been limited in part by low gene transfer efficiencies. We found that the presence of stromal-derived factor 1 (SDF-1alpha)/CXCL12 during retroviral transduction significantly enhanced, in a dose-dependent fashion, gene transfer into immature subsets of high proliferative human and murine hematopoietic progenitor cells.

CD26 is essential for normal G-CSF-induced progenitor cell mobilization as determined by CD26-/- mice.

Objective: In spite of the wide usage of mobilized peripheral blood hematopoietic stem and progenitor cells (HSC/HPC) for transplantation, the mechanism of granulocyte colony-stimulating factor (G-CSF)-induced HSC/HPC mobilization has yet to be fully determined. Our previous studies suggested that that G-CSF-induced mobilization may involve the extracellular peptidase CD26 (DPPIV/dipeptidylpeptidase IV). We set out to establish whether CD26 was an essential component of normal G-CSF-induced mobilization of HSC/HPC.

Distinct requirements for Stat4 and Stat6 in hematopoietic progenitor cell responses to growth factors and chemokines.

Hematopoietic progenitor cell (HPC) homeostasis is critical in maintaining innate immunity and healing processes. Recently, we demonstrated that Th1 cells regulate HPC homeostasis, partly based on altered homeostasis in Stat4- and Stat6-deficient mice. To explore changes in HPC responsiveness in altered T helper cell environments, we directly examined growth factor-stimulated colony formation and chemokine-induced myelosuppression of HPC in Stat4- and Stat6-deficient bone marrow cells.

Importance of predosing of recombinant human thrombopoietin to reduce chemotherapy-induced early thrombocytopenia.

Purpose: Recombinant human thrombopoietin (rhTPO) increases platelets, and the peak response of rhTPO is delayed and is, therefore, not uniformly effective when administered after chemotherapy. The purpose of this study was to identify an effective schedule of rhTPO to best attenuate early thrombocytopenia.

Patients And Methods: Cohorts of six patients with sarcoma (66 assessable patients) were treated sequentially with doxorubicin and ifosfamide (AI), with rhTPO by a fixed dose and varying schedules being administered before and/or after chemotherapy in cycle 2 and subsequent cycles.

Synergistic activation of p70S6 kinase associated with stem cell factor in MO7e cells.

Stem cell factor (SCF) is an early-acting cytokine inducing proliferative synergy with other cytokines in hematopoietic cells. We earlier showed that p21 was synergistically induced in SCF synergy and the p44/42 MAPK pathway was essential for the transcriptional control of p21. SCF synergy accompanies protein synthesis.

Mobilization of hematopoietic progenitor cells in healthy volunteers by AMD3100, a CXCR4 antagonist.

Stromal cell-derived factor 1 (SDF1/CXCL12) and its cognate receptor, CXCR4, play key regulatory roles in CD34+ cell trafficking. We investigated whether AMD3100, a selective CXCR4 antagonist, could mobilize hematopoietic progenitor cells from marrow to peripheral blood in healthy human volunteers. Initially, 10 persons each received a single dose of AMD3100 (80 microsubcutaneously), which induced rapid, generalized leukocytosis associated with an increase in peripheral blood CD34+ cells, representing pluripotent hematopoietic progenitors by in vitro colony-forming unit assays, from 3.

Selective enhancement of multipotential hematopoietic progenitors in vitro and in vivo by IL-20.

In a search for novel growth factors, we discovered that human interleukin-20 (IL-20) enhanced colony formation by CD34+ multipotential progenitors. IL-20 had no effect on erythroid, granulocyte-macrophage, or megakaryocyte progenitors. IL-20 transgenic mice increased the numbers and cell cycling of multipotential but not other progenitors.

Fanconi anemia type C and p53 cooperate in apoptosis and tumorigenesis.

Fanconi anemia (FA) is a recessive genomic instability syndrome characterized by developmental defects, progressive bone marrow failure, and cancer. FA is genetically heterogeneous, however; the proteins encoded by different FA loci interact functionally with each other and with the BRCA1, BRCA2, and ATM gene products. Although patients with FA are highly predisposed to the development of myeloid leukemia and solid tumors, the alterations in biochemical pathways responsible for the progression of tumorigenesis in these patients remain unknown.

P-selectin enhances generation of CD14+CD16+ dendritic-like cells and inhibits macrophage maturation from human peripheral blood monocytes.

Endothelial cells play a critical role in monocyte differentiation. Platelets also affect terminal maturation of monocytes in vitro. P-selectin is an important adhesion molecule expressed on both endothelial cells and activated platelets.

Stromal cell-derived factor-1/CXCL12 directly enhances survival/antiapoptosis of myeloid progenitor cells through CXCR4 and G(alpha)i proteins and enhances engraftment of competitive, repopulating stem cells.

Stromal cell-derived factor-1 (SDF-1/CXCL12) enhances survival of myeloid progenitor cells. The two main questions addressed by us were whether these effects on the progenitors were direct-acting and if SDF-1/CXCL12 enhanced engrafting capability of competitive, repopulating mouse stem cells subjected to short-term ex vivo culture with other growth factors. SDF-1/CXCL12 had survival-enhancing/antiapoptosis effects on human bone marrow (BM) and cord blood (CB) and mouse BM colony-forming units (CFU)-granulocyte macrophage, burst-forming units-erythroid, and CFU-granulocyte-erythroid-macrophage-megakaryocyte with similar dose responses.

NF-kappaB promotes breast cancer cell migration and metastasis by inducing the expression of the chemokine receptor CXCR4.

Metastasis of cancer cells is a complex process involving multiple steps including invasion, angiogenesis, and trafficking of cancer cells through blood vessels, extravasations, organ-specific homing, and growth. While matrix metalloproteinases, urokinase-type plasminogen activator, and cytokines play a major role in invasion and angiogenesis, chemokines such as stromal derived factor-1alpha (SDF-1alpha) and their receptors such as CXCR4 are thought to play a critical role in motility, homing, and proliferation of cancer cells at specific metastatic sites. We and others have previously reported that the extracellular signal-activated transcription factor NF-kappaB up-regulates the expression of matrix metalloproteinases, urokinase-type plasminogen activator, and cytokines in highly metastatic breast cancer cell lines.

Effect of leukotactin-1 on the protection in vivo of myeloid progenitor cells against cytotoxic chemotherapeutics.

Leukotactin-1 (Lkn-1) is a human CC chemokine that induces chemotaxis of neutrophils, monocytes, eosinophils, and lymphocytes and suppresses colony formation of myeloid progenitor cells in vitro. Present studies evaluated the myeloprotective capabilities of Lkn-1 in vivo against Ara-C and 5-fluorouracil (5-FU). The effect of Lkn-1 on myelopoiesis was first assessed in vivo by injecting recombinant Lkn-1 in C3H/HeJ mice.

Osteoprotegerin inhibits proliferation of myeloid progenitor cells.

Osteoprotegerin (OPG) and decoy receptor 3 (DcR) are soluble members of the tumor necrosis factor receptor (TNFR) superfamily. Because the proteins are found in the circulation, their effect on hematopoietic progenitor cells was examined. OPG suppressed colony formation by all myeloid progenitor cells stimulated with one or more growth factors.

Profiling of differentially expressed apoptosis-related genes by cDNA arrays in human cord blood CD34+ cells treated with etoposide.

Objective: Understanding the molecular events that contribute to survival of and drug-induced apoptosis in hematopoietic stem and progenitor cells (HSC/P) can have impact on more rational approaches to blood cancer therapeutic design, as well as on strategies to minimize toxic side effects of chemotherapeutic drugs. Here we sought to systematically evaluate the basic molecular components and main pathways that govern and mediate cellular response initiated within human CD34(+) cells to etoposide-induced apoptosis.

Materials And Methods: Human CD34(+) cells were isolated from umbilical cord blood (CB) and expanded in vitro.

Src kinase, but not the src kinase family member p56lck, mediates stromal cell-derived factor 1alpha/CXCL12-induced chemotaxis of a T cell line.

Stromal cell-derived factor 1 (SDF-1/CXCL12) is believed to mediate migration of leukocytes. To explore potential mechanisms, we evaluated the signal transduction pathways activated by SDF-1 in the Jurkat T cell line. Src kinase was phosphorylated and mitogen-activated protein kinase/extracellular signal-regulated kinase (MAPK/ERK) activated in a time-related fashion after SDF-1 stimulation.

4-1BB ligand stimulation enhances myeloid dendritic cell maturation from human umbilical cord blood CD34+ progenitor cells.

In humans, at least two subsets of dendritic cells (DCs) are identified on the basis of differential surface expression of CD11c antigens. CD11c(+) and CD11c(-) cells are respectively of myeloid and lympholoid origin and functionally distinct, eliciting inflammatory and tolerant T cell responses. We investigated whether 4-1BB ligand (4-1BBL), a member of the tumor necrosis factor (TNF) family, is involved in the maturation process to mature myeloid DCs during in vitro DC differentiation from immature DCs derived from human umbilical cord blood (CB) CD34(+) progenitor cells.

Cell surface peptidase CD26/DPPIV mediates G-CSF mobilization of mouse progenitor cells.

CXC ligand 12 (CXCL12; also known as stromal cell-derived factor 1alpha/SDF-1alpha) chemoattracts hematopoietic stem and progenitor cells (HSCs/HPCs) and is thought to play a crucial role in the mobilization of HSCs/HPCs from the bone marrow. CD26 (dipeptidylpeptidase IV [DPPIV]) is a membrane-bound extracellular peptidase that cleaves dipeptides from the N-terminus of polypeptide chains. CD26 has the ability to cleave CXCL12 at its position-2 proline.

High-efficiency recovery of functional hematopoietic progenitor and stem cells from human cord blood cryopreserved for 15 years.

Transplanted cord blood (CB) hematopoietic stem cells (HSC) and progenitor cells (HPC) can treat malignant and nonmalignant disorders. Because long-term cryopreservation is critical for CB banking and transplantation, we assessed the efficiency of recovery of viable HSCHPC from individual CBs stored frozen for 15 yr. Average recoveries (+/- 1 SD) of defrosted nucleated cells, colony-forming unit-granulocyte, -macrophage (CFU-GM), burst-forming unit-erythroid (BFU-E), and colony-forming unit-granulocyte, -erythrocyte, -monocyte, and -megakaryocyte (CFU-GEMM) were, respectively, 83 +/- 12, 95 +/- 16, 84 +/- 25, and 85 +/- 25 using the same culture conditions as for prefreeze samples.

Transgenic expression of stromal cell-derived factor-1/CXC chemokine ligand 12 enhances myeloid progenitor cell survival/antiapoptosis in vitro in response to growth factor withdrawal and enhances myelopoiesis in vivo.

Hemopoiesis is regulated in part by survival/apoptosis of hemopoietic stem/progenitor cells. Exogenously added stromal cell-derived factor-1 ((SDF-1)/CXC chemokine ligand (CXCL)12) enhances survival/antiapoptosis of myeloid progenitor cells in vitro. To further evaluate SDF-1/CXCL12 effects on progenitor cell survival, transgenic mice endogenously expressing SDF-1/CXCL12 under a Rous sarcoma virus promoter were produced.

Cell surface peptidase CD26/dipeptidylpeptidase IV regulates CXCL12/stromal cell-derived factor-1 alpha-mediated chemotaxis of human cord blood CD34+ progenitor cells.

CD26/dipeptidylpeptidase IV (DPPIV) is a membrane-bound extracellular peptidase that cleaves dipeptides from the N terminus of polypeptide chains. The N terminus of chemokines is known to interact with the extracellular portion of chemokine receptors, and removal of these amino acids in many instances results in significant changes in functional activity. CD26/DPPIV has the ability to cleave the chemokine CXCL12/stromal cell-derived factor 1alpha (SDF-1alpha) at its position two proline.

P21waf-1-Chk1 pathway monitors G1 phase microtubule integrity and is crucial for restriction point transition.

Microtubule-disruption (MTD) is often thought to arrest the mammalian cell cycle only during mitosis. However, MTD has also been demonstrated to arrest cells during interphase at a G(1)-phase point we call G(1)MTA. Microtubule integrity is now shown to be required for progression past G(1)MTA and the mammalian restriction-point.

Down-regulation of the myeloid homeobox protein Hex is essential for normal T-cell development.

The haematopoietic homeobox gene Hex (also called Prh) is expressed in myeloid cells and B cells but not T cells. To investigate whether Hex levels might play a role in myeloid versus T-cell development, two types of transgenic mouse lines were constructed, each with ectopic expression of Hex in T cells (CD11a/Hex and Lck/Hex). Both these types of transgenic mouse had the same defects in T-cell maturation, indicating that proper T-cell development may be dependent not just on the up-regulation of lymphoid-specific transcriptional regulators but also on the co-ordinated down-regulation of myeloid-specific transcriptional regulators such as Hex.