scholarly journals Possible mechanisms accounting for the growth factor independence of hematopoietic progenitors from umbilical cord blood

Blood ◽  
1994 ◽  
Vol 84 (11) ◽  
pp. 3679-3684 ◽  
Author(s):  
KR Schibler ◽  
Y Li ◽  
RK Ohls ◽  
NC Nye ◽  
MC Durham ◽  
...  

Hematopoietic progenitors obtained from the bone marrow of healthy adults fail to undergo clonogenic maturation in vitro if a source of hematopoietic growth factors is not included in the culture dishes. In contrast, a fraction of similarly purified progenitors obtained from umbilical cord blood undergo clonogenic maturation even in the absence of added growth factors. We postulated that production of hematopoietic growth factors within the culture dishes containing the progenitors of umbilical cord blood origin might be responsible. We postulated further, that this production might be by non-progenitor cells co- plated along with the progenitors, or alternatively by CD34+ cells themselves, or by cells clonally derived from CD34+ cells. To test these possibilities we first assessed the effect of including in the cultures neutralizing antibody directed against various growth factors. Inclusion of anti-granulocyte macrophage colony-stimulating factor (GM- CSF) and anti-interleukin-3 (IL-3) (but not anti-IL-2) significantly reduced the growth factor independence of cord blood progenitors (P > .005 and P > .01). Inclusion of both anti-GM-CSF and anti-IL-3 almost completely ablated the spontaneous colony growth (P > .001). Inclusion of IL-10 also reduced, in a concentration-dependent fashion, the spontaneous generation of umbilical cord blood-derived colonies. Transcripts for GM-CSF and IL-3 were detected, by reverse transcriptase- polymerase chain reaction (RT-PCR), in the CD34+ cells from cord blood and from adult marrow. When plated without added growth factors, however, the CD34+ cells of adult marrow origin failed to produce colonies, whereas 6% of cord blood CD34+ cells similarly cultured did so. When these growth factor independent colonies were plucked from culture, transcripts for GM-CSF and IL-3 were identified in all. We conclude that production of GM-CSF and IL-3 occurs within culture dishes containing hematopoietic progenitors of umbilical cord origin, and that this explains some of their apparently unique features of in vitro growth.

Transfusion ◽  
2008 ◽  
Vol 48 (10) ◽  
pp. 2235-2245 ◽  
Author(s):  
Eun Jung Baek ◽  
Han-Soo Kim ◽  
Sinyoung Kim ◽  
Honglien Jin ◽  
Tae-Yeal Choi ◽  
...  

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 2479-2479
Author(s):  
Melissa S. Holtz ◽  
Stephen J. Forman ◽  
Ravi Bhatia

Abstract While imatinib mesylate is a highly effective treatment for CML, there is accumulating evidence that it may not adequately target quiescent malignant HSCs. In vitro exposure to imatinib inhibits CML progenitor growth primarily through suppression of abnormally enhanced proliferation. Apoptosis appears to be restricted to dividing cells while quiescent progenitors are resistant to apoptosis. One approach to more effectively enhance the sensitivity of HSCs to imatinib may be to induce them to cycle using hematopoietic growth factors (GF). We have shown that exposure of CML CD34+ progenitors to imatinib (1μM) in high GF conditions (100ng/ml SCF and FL3, 20ng/ml IL6, G-CSF and IL3) reduced the total number of viable, undivided cells compared to control cells cultured in 100-fold lower GF conditions (low GF). High GF treated cells were more proliferative but less sensitive to imatinib-mediated apoptosis (Blood2004, 104:2967). We hypothesized that pre-stimulation with high GF prior to imatinib exposure would further reduce viable, non-dividing CML progenitors. CML CD34+ cells were cultured in high GF for 48 hours and then exposed to imatinib (1μM) for 48 hours in either high or low GF conditions. Compared to cells exposed to imatinib without any pre-stimulation, high GF pre-stimulation significantly reduced imatinib-mediated inhibition of proliferation in both low GF (22±5%, p=0.0009) and high GF (18±3%; p=0.0003). Pre-stimulation decreased imatinib-mediated apoptosis when compared to the same conditions with no pre-stimulation [19±2% for imatinib treatment in low GF (p<0.0001) and 7±3% in high GF (p=0.064)]. However, although overall apoptosis decreased, pre-stimulation resulted in increased apoptosis of undivided cells exposed to imatinib in either low GF (14±5%; p=0.022) or high GF (13±6%, p=0.065). These results are notable since increased apoptosis of undivided cells was not previously observed in any other condition. Importantly, the percent of input cells remaining viable and undivided decreased significantly for pre-stimulated cells exposed to imatinib in low GF (19±3%; p<0.0001) or high GF (7±2%; p=0.016). These results highlight the potential use of GF stimulation to enhance targeting of CML HSC. Additional studies examined whether GF readily available for clinical use (G-CSF and/or GM-CSF) could also enhance imatinib targeting of quiescent CML progenitors. CML CD34+ cells were exposed to 1mM imatinib for 96 hours in a basal low GF cocktail (250pg/ml G-CSF, 10pg/ml GM-CSF, 200pg/ml SCF, 1ng/ml IL6, 200pg/ml MIP1α, 50pg/ml LIF) alone or with the addition of G-CSF (50ng/ml) and/or GM-CSF (10ng/ml). While overall apoptosis decreased, apoptosis of undivided cells significantly increased for cells exposed to imatinib in high concentrations of G-CSF + GM-CSF compared to those in basal GF alone (8.7±1.3%; p=0.007). The percent of input cells remaining viable and undivided in the presence of imatinib significantly decreased with high G-CSF + GM-CSF compared to basal GF alone (7.2%±1.1; p=0.007). In conclusion, pre-stimulation with high concentrations of GF can lead to increased proliferation and enhance reduction of non-dividing CML CD34+ cells by imatinib. These results are of significance because non-dividing primitive cells have previously proven highly resistant to elimination by imatinib and support translational clinical studies to investigate whether intermittent GF administration can enhance elimination of residual CML stem and progenitor cells in patients in remission on imatinib treatment.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 2322-2322
Author(s):  
Takashi Yoshikubo ◽  
Yoshihiro Matsumoto ◽  
Masahiko Nanami ◽  
Takayuki Sakurai ◽  
Hiroyuki Tsunoda ◽  
...  

Abstract Thrombopoietin (TPO, the ligand for c-mpl) is a key factor for megakaryopoiesis. Several clinical trials of TPO have been conducted for thrombocytopenia without much success due to, in part, the production of neutralized antibodies against endogenous TPO, which causes thrombocytopenia. To overcome this problem, we previously demonstrated that mouse type minibody against c-mpl, with an amino acid sequence totally different from TPO, showed megakaryopoiesis and increased platelet numbers in monkey. This time, using CDR grafting, we generated a humanized sc(Fv)2VB22B minibody (huVB22B) against c-mpl for therapeutic use. The new minibody showed almost the same activity in vitro as TPO and the mouse type minibody, confirmed by both a human megakaryocyte cell (CD41+) differentiation assay and a proliferation assay with TPO-dependent cell line, M-07e. Single sc or iv administration of huVB22B to cynomolgus monkeys showed a dose-dependent increase in platelet numbers. Pharmacokinetic analysis showed that the plasma half-life (T1/2) of huVB22B at iv and sc administration to cynomolgus monkeys was 7–8 h and 11–16 h, respectively. After administration of huVB22B, the platelets of these monkeys increased and showed functional aggregation in response to ADP in vitro. Repeated administration of huVB22B (0.2, 2 and 20mg/kg/week) revealed that the increase in platelet level in cynomolgus monkeys was maintained for a month. Very slight reticular fibers in bone marrow were detected in a high dose group (20mg/ kg). No overt changes were detected by toxicity evaluations including clinical pathology and histopathology in 0.2 and 2mg/kg groups. No neutralized activities in plasma were observed during these experiments. Next, we examined the activities of huVB22B on human bone marrow-derived CD34-positive cells (BM-CD34+) and umbilical cord blood-derived CD34-positive cells (UCB-CD34+) in vitro. BM-CD34+ and UCB-CD34+ cells were cultured with huVB22B in serum free medium. HuVB22B induced differentiation of CD41+ cells from BM-CD34+ or UCB-CD34+ cells in a similar dose-dependent manner. However, UCB-CD34+ cells showed greater proliferation in response to huVB22B compared to BM-CD34+ cells. We then examined the in vivo activities of huVB22B on UCB CD34+ cells by treating NOD/SCID mice transplanted with human UCB-CD34+ cells with huVB22B and examining the bone marrow cells of the mice. The results showed that, compared with the control, administration of huVB22B showed an increase in the number of human hematopoietic progenitor cells (CD34+), lymphoid lineage cells (CD19+), and myeloid lineage cells (CD33+) in addition to human CFU-Meg cells (CD41+). These results suggest that c-mpl stimulation in vivo after transplantation might increase engraftment of progenitor cells in the bone marrow microenvironment and subsequently induce differentiation to multilineage cells. Umbilical cord blood transplantation faces frequent complications including a low-level stem/progenitor cell engraftment and delayed platelet recovery. Our results suggest that c-mpl stimulation might be used to increase the engraftment of UCB stem/progenitor cells and shorten the time of platelet recovery following UCB transplantation.


Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1534-1545 ◽  
Author(s):  
R O'Connor ◽  
A Cesano ◽  
B Lange ◽  
J Finan ◽  
PC Nowell ◽  
...  

Cells from 10 cases of childhood acute T-lymphoblastic leukemia (T-ALL) were cultured in the presence of recombinant human interleukins (rhIL) or colony-stimulating factors (CSF) to analyze their growth factor requirements and differentiative potential. Although cells from most leukemic samples displayed a short-term proliferative response to several hematopoietic growth factors, only the ones featuring chromosomal translocations could be established as permanent cell lines. Two cell lines could be initiated only in the presence of IL-3 (TALL-103 and TALL-106), one in granulocyte-macrophage CSF (GM-CSF) (TALL-101), and one in IL-2 (TALL-104); only one cell line (TALL-105) was originated in the absence of growth factors. The TALL-101 and TALL- 103 cell lines, derived from very immature T-ALL cases, underwent growth factor-dependent phenotypic conversion (lymphoid to myeloid). However, the T-cell receptor rearrangement and karyotype of the original leukemic clones were retained. In contrast, the TALL-104, - 105, and -106 cell lines which originated from more mature T-ALL cases, maintained a T-lymphoblastic phenotype regardless of the growth factors in which they were expanded. These data demonstrate in vitro the aggressive nature of T-ALL cases bearing chromosomal abnormalities, and indicate that the lineage commitment of the malignant clone depends on its stage of maturation in T-cell ontogeny.


Blood ◽  
1991 ◽  
Vol 77 (7) ◽  
pp. 1534-1545 ◽  
Author(s):  
R O'Connor ◽  
A Cesano ◽  
B Lange ◽  
J Finan ◽  
PC Nowell ◽  
...  

Abstract Cells from 10 cases of childhood acute T-lymphoblastic leukemia (T-ALL) were cultured in the presence of recombinant human interleukins (rhIL) or colony-stimulating factors (CSF) to analyze their growth factor requirements and differentiative potential. Although cells from most leukemic samples displayed a short-term proliferative response to several hematopoietic growth factors, only the ones featuring chromosomal translocations could be established as permanent cell lines. Two cell lines could be initiated only in the presence of IL-3 (TALL-103 and TALL-106), one in granulocyte-macrophage CSF (GM-CSF) (TALL-101), and one in IL-2 (TALL-104); only one cell line (TALL-105) was originated in the absence of growth factors. The TALL-101 and TALL- 103 cell lines, derived from very immature T-ALL cases, underwent growth factor-dependent phenotypic conversion (lymphoid to myeloid). However, the T-cell receptor rearrangement and karyotype of the original leukemic clones were retained. In contrast, the TALL-104, - 105, and -106 cell lines which originated from more mature T-ALL cases, maintained a T-lymphoblastic phenotype regardless of the growth factors in which they were expanded. These data demonstrate in vitro the aggressive nature of T-ALL cases bearing chromosomal abnormalities, and indicate that the lineage commitment of the malignant clone depends on its stage of maturation in T-cell ontogeny.


Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 4218-4218
Author(s):  
Nicholas J. Greco ◽  
Brandon Eilertson ◽  
Jason J. Banks ◽  
Paul Scheid ◽  
Marcie Finney ◽  
...  

Abstract To assess in vitro angiogenesis, cellular co-culture assays have been utilized to study adherence, spreading, differentiation and proliferation, and migration of endothelial cells. Formation of tubule or capillary-like networks is influenced by the presence of vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF) but other factors provided by cell sources and/or direct contact with multiple cell types may facilitate this formation. The hypothesis of this study is that umbilical cord blood (UCB)-derived endothelial precursor cells (EPCs) may influence the formation of human umbilical vein endothelial cell (HUVEC) tubule structures during angiogenesis. Methods: UCB-derived EPCs were isolated from CD133negative cells after a 7-day culture on human fibronectin in EGM-2 media. Tubule formation was evaluated (passage 1–2, 20 x 103 or 2 x 103 cells) by adding HUVECs without or with EPCs to cultures of human bone marrow-derived mesenchymal stromal cells (MSCs) under normoxic (20%) conditions (37°C, 5% CO2, containing VEGF, epidermal growth factor, FGF, insulin-like growth factor, heparin, hydrocortisone, and ascorbic acid in EGM-2 medium) for a 2-week period. HUVECs were added to cultures without or with labeling with Vybrant® CM-DiI which allows the temporal observation of tubule formation progress and cellular incorporation. Final tubule formation was confirmed using a primary anti-CD31 (PECAM) antibody followed by a FITC-conjugated secondary antibody for signal amplification. Results: After 2–4 days, linear aggregates of labeled HUVECs (2-D arrangement) were observed. After 14 days, there was remodeling of HUVECs into the development of a 3D network of linear and branched tubule structures. EPCs facilitated the formation of tubules affecting both the extent of tubule formation and also enhanced proliferation of HUVEC cells. A minority (< 5%) of EPCs were incorporated into developing tubules (estimated using CM-Dil-labeled EPCs). To quantify tubule formation, digital pictures of representative areas of culture wells (2–4/well) were acquired. Using Image Pro Plus software, tubules were quantified using multi-parameter analysis with respect to length, area, and perimeter. The presence of EPCs (equal to the number of added HUVECs) significantly enhanced all parameters. In comparison to control samples, the presence of EPCs increased the area, perimeter and size by 15.2-fold, 3.4-fold, and 3.2-fold, respectively. Confocal microscopy revealed that the co-cultures formed anatamoses, indicating the formation of a connected network. Conclusions: Taken together, these results suggest that the presence of cord blood-derived EPCs facilitate tubule formation and development via a heterotypic cell-cell interaction without integrating into the angiogenic structures. Further studies will evaluate the secretion of cytokines and growth factors.


2005 ◽  
Vol 14 (2) ◽  
pp. 223-230 ◽  
Author(s):  
Rui Jun Su ◽  
Karen Li ◽  
Xiao Bing Zhang ◽  
Patrick Man Pan Yuen ◽  
Chi Kong Li ◽  
...  

Blood ◽  
2006 ◽  
Vol 108 (11) ◽  
pp. 4213-4213
Author(s):  
Alexander Kiani ◽  
Hanna Kuithan ◽  
Friederike Kuithan ◽  
Satu Kyttaelae ◽  
Ivonne Habermann ◽  
...  

Abstract NFAT (Nuclear Factor of Activated T cells) transcription factors are a family of five proteins that are primarily known for their central role in the regulation of inducible gene expression in activated T cells. It is now clear that NFAT proteins are also expressed in various non-immune cell types, where they regulate the expression of genes involved in such diverse cellular processes as proliferation, apoptosis and differentiation. We have previously shown that NFATc2 is strongly expressed in human CD34+ cells and megakaryocytes, but not in purified peripheral blood neutrophil granulocytes and monocytes. Furthermore, granulocytic differentiation of CD34+ cells in vitro was paralleled by the rapid and profound suppression of NFATc2 mRNA and protein. The function of NFATc2 in CD34+ cells, however, is unknown, and no information exists on the expression or regulation of other NFAT family members in CD34+ cells or during heamtopoietic differentiation. To provide a systematic basis for further functional analysis, we established in the present study a comprehensive expression profile of all five NFAT family members in CD34+ cells and during their in vitro differentiation into neutrophil, eosinophil, erythroid and megakaryocytic lineages. CD34+ cells were purified from umbilical cord blood and cultured in the presence of cytokines or cytokine combinations inducing differentiation of the respective lineages. At several time-points during the culture, the efficacy and specificity of the differentiation was monitored by morphological examination of cytospin preparations as well as by analysis of lineage-specific cell surface markers. By quantitative RT-PCR, NFATc3 and NFAT5 were the NFAT family member found to be most prominently expressed in CD34+ cells of both peripheral blood and umbilical cord blood, as well as in the immature CD34+CD38− subpopulation of cells. NFAT expression during the differentiation of umbilical cord blood CD34+ cells into the diverse hematopoietic lineages followed a family member- and lineage-specific pattern. Neutrophil differentiation was accompanied by a rapid suppression of transcript level for all NFAT family members. In contrast, eosinophil, erythrocyte and megakaryocyte differentiation was paralleled by an upregulation of NFATc3, NFATc1/NFATc3 and NFATc1 mRNA, respectively. The most obvious lineage-specific pattern was observed for NFATc4, where transcript levels were low in CD34+ cells and either not or only transiently increased in neutrophil, eosinophil and erythrocyte differentiation; in contrast, they were specifically upregulated about 10-fold in the megakaryocytic lineage. The expression profile of NFAT family members in developing hematopoietic cells of diverse lineages presented here will allow predicting and directly assessing the role of individual NFAT family members in hematopoietic differentiation.


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