bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Impact of Imatinib Therapy on Adult Philadelphia Positive Acute Lymphoblastic Leukaemia (ALL): Early Results from the UKALL12/ECOG 2993 Study.
Authors: Patel Bella , Goldstone Anthony H. , Ross Philip , Richards Sue , Foroni Letizia , Chopra R. , Fielding Adele 
Published: April 2020

Abstract
Modern protocols for the treatment of adults with Philadelphia positive (Ph+ve) ALL produce high complete remission (CR) rates. Despite this, the overall prognosis remains poor. Imatinib, an inhibitor of the BCR-ABL protein tyrosine kinase, may be a useful therapeutic agent for this disease. The arm of the MRC UKALL-XII/ECOG E2993 trial for patients with Ph+ve adult ALL was amended in 2003 to include Imatinib in the treatment protocol. Following induction chemotherapy those in haematological CR went on to receive treatment with Imatinib at 400mg/day, escalated to 600mg/day if tolerated. Those patients with a sibling, matched unrelated donor or related single haplotype match went on to allogeneic transplantation, whilst those with no available donor received an autograft. Chemotherapy alone was given to patients ineligible for a transplant procedure. All patients received Imatinib as maintenance therapy until frank relapse. 30 consecutive patients had a minimum of 12 months follow up. Sufficient data was available in 27 patients. The median age was 45 years (range 15 to 60), 59% were male, 96% were B-lineage, 4% were null lineage. Median white cell count at diagnosis was 24.1 X109/l. Median follow up was 15.6 months. The overall remission rate was 89%. The median time to CR was 28 days (range 19–93 days). Five (19%) patients received an autograft, 15 (56%) received an allograft. and 7 patients (26%) received chemotherapy alone. The event free survival (EFS) and overall survival (OS) at 1 year was 56% and 59% respectively. There were 7 deaths in remission (23%), 6 of which were transplant related. There were 7 relapses, 3 occurred in patients treated with chemotherapy alone, 2 prior to transplantation and 2 following allogeneic transplantation. These results were compared to 236 historic study patients in first CR after the same induction therapy but who did not receive Imatinib. There were no significant differences between the 2 groups with respect to gender, age, WBC or immunophenotype. Four percent received an autograft, 42% received an allograft and 47% received chemotherapy alone. A further 7% received a non-protocol transplant regimen. The EFS and OS of the historic controls was 35% and 56% respectively, with a comparable rate of deaths in remission (22%). Although the superior EFS in the Imatinib treated patients may be confounded by the greater number of allogeneic transplants in that group, the addition of Imatinib, even after achievement of CR does appear to enhance EFS in comparison to that seen in historical controls. Further follow up is needed to confirm an effect on overall survival and an independent anti-leukaemic effect of Imatinib in adult ALL.
Increased Stem Cell Mobilization Proficiency in Aged Mice.
Authors: Geiger Hartmut , Daria Deidre , Nattamai Kalpana J. , Xing Zhenlan 
Published: April 2020

Abstract
The ability of healthy, older individuals to undergo stem cell mobilization in response to granulocyte colony-stimulating factor (G-CSF) has not been specifically investigated. Aging is usually associated with an overall decline in tissue and cellular function. Therefore it is anticipated that the ability to mobilize stem cells in response to G-CSF may be reduced in aged individuals, although whether or not a negative correlation exists between age and mobilization is still under debate. We analyzed the influence of aging on the mobilization proficiency in healthy mice. Young 2–3 month old and aged 20–26 month old, which corresponds to a human age of 70, were mobilized according to standard procedures. The frequency of hematopoietic progenitor cells in peripheral blood (PB) of aged mice was 3- fold elevated over the frequency found in PB of young mice. The aged animals possessed the ability to mobilize increased numbers of primitive hematopoietic cells despite a slight, but significant anemia. This 3-fold difference in stem cell frequency in PB was further confirmed by long-term transplantation experiments. To determine if the increased ability to mobilize is intrinsic to aged hematopoietic stem cells or driven by age-associated, extrinsic changes in the BM microenvironment, a competitive mobilization assay based on the Ly5.2/Ly5.1 mismatch system was used. The genetic origin of the CFCs was determined by flow cytometry. In this assay, as previously reported, aged BM HSCs contribute to only 30% chimerism in PB prior to mobilization, resulting in a 1:2 ratio in favor of young cells in PB chimerism 3 months post-transplant. In contrast, when we analyzed the CFC chimerism of the competitively transplanted animals post-mobilization, 85% of all CFC from PB were derived from cells from old mice, strongly arguing that increased mobilization proficiency is a) not a simple consequence of the increased CFC content in aged BM and b) to a large extent intrinsic to the aged primitive hematopoietic cell, and thus relatively independent from the aged BM microenvironment. These data also imply that the stroma stem cell/interaction might change with age.
Genetic Interaction between SCL and c-Kit in Hematopoietic Cell Survival.
Authors: Lacombe Julie , Krosl Gorazd , Herblot Sabine , Martin Richard , Aplan Peter D. , Begley C.Glenn , Sauvageau Guy , Hoang Trang 
Published: April 2020

Abstract
The c-Kit tyrosine kinase receptor and the SCL/Tal1 (Stem Cell Leukemia) transcription factor are crucial to hematopoiesis and are co-expressed by hematopoietic progenitors. In the present study, we directly address the question whether SCL and c-Kit establish a code for the fate of multipotent progenitors in the adult. We therefore proceeded to loss and gain of function experiments, via retroviral mediated gene transfer in primary hematopoietic cells. We show that SCL is functionally required to sustain the survival of c-Kit+ cells in response to Steel Factor (Kit ligand), but not to GM-CSF and IL-3. Interfering with SCL function using a DNA-binding defective SCL mutant (ΔbSCL) caused a 100-fold loss of multipotent progenitors, due to massive apoptotic death in the c-Kit+ fraction, indicating that the DNA binding function of SCL is essential in cell survival. An antisense SCL also caused apoptosis in c-Kit+ cells, which was rescued by co-delivering SCL in the sense orientation. Furthermore, SCL sets threshold for the response of multipotent progenitors to Steel factor without affecting their response to IL-3 or GM-CSF, demonstrating the specificity of SCL for c-Kit-dependent pathway. Moreover, SCL levels in purified hematopoietic progenitors (HSC, CMP, MEP, CLP) were 3.5 to 15-fold decreased in W41 W41 mice that have a hypomorphic c-Kit allele when compared to age-matched wild type controls. Conversely, ectopic SCL expression is sufficient to bypass c-Kit signalling to suppress apoptosis and increase the proliferative potential of multipotent progenitors, as anemia and other hematopoietic defects caused by a hypomorphic c-Kit allele were rescued by introducing an SCL transgene into the W41 W41 background. We conclude that SCL operates within the c-Kit pathway to suppress apoptosis and determine the clonal output of adult multipotent progenitors. To define the pathway through which SCL suppresses apoptosis in hematopoietic progenitors, we performed microarrays analysis on Δb-SCL expressing cells and identified novel survival genes that were confirmed to be direct SCL targets by chromatin immunoprecipitation. Finally, the expression of these target genes was decreased in purified progenitors from W41 W41 mice as assessed by quantitative PCR. Together, this study reveals a new and essential genetic pathway involving SCL downstream of c-Kit signalling for the survival of hematopoietic progenitors.
p210BCR-ABL by down Regulating FLI-1 Reprograms Megakaryocytic Progenitors to the Erythroid Lineage.
Authors: Buet Dorothée , Raslova Hana , Juban Gaëtan , Geay Jean-François , Jarrier Peggy , Turhan Ali G. , Morle François , Vainchenker William , Louache Fawzia 
Published: April 2020

Abstract
Blood cells derive from a common multipotent stem cell that undergoes successive commitment steps with progressive restriction in differentiation ability. A close developmental relationship exists between the erythroid and megakaryocytic (MK) lineages as both lineages derive from a common bipotent progenitor. The nature of the events governing erythroid-specific or MK-specific programming is yet poorly understood. To approach this issue, we used an ectopic expression of the p210 BCR-ABL oncoprotein in adult primary human CD34+ progenitor cells. In culture conditions favoring the development of both erythroid and MK cells, we observed a major expansion of the erythroid lineage occurring at the expense of the MK lineage. The combined use of a p210BCR-ABL tyrosine kinase inhibitor together with single cell cloning experiments on prospectively isolated CD41+CD42− progenitor cells allowed us to identify that a part of MK progenitor cells were reprogrammed by p210BCR-ABL to take an erythroid fate. A similar lineage switching was seen after p210BCR-ABL expression in the human megakaryoblastic MO7e cell line. Microarrays and semi-quantitative RT-PCR studies showed that expression of p210BCR-ABL was associated with a decreased expression of the FLI-1 transcription factor. Moreover, re-expression of FLI-1 in p210BCR-ABL-transduced MO7e cells that had acquired an erythroid phenotype rescued the MK programming. Finally, a partial inhibition of FLI-1 in normal CD41+CD42− progenitor cells with a shRNAi led to an increased erythroid differentiation at the expense of MK differentiation. These results demonstrate that progenitor cells apparently committed to the MK lineage may be re-specified to the erythroid lineage by an ectopic expression of p210BCR-ABL and that the FLI-1 transcription factor is a key factor in the balance between erythroid versus MK commitment.
Protein Phosphatase2A Regulates Stromal Cell- Derived Factor-1 Mediated Responses of CD34+ Cord Blood Cells.
Authors: Basu Sunanda , Graham-Evans Barbara , Broxmeyer Hal E. 
Published: April 2020

Abstract
The chemokine stromal cell- derived factor-1(SDF-1) and its receptor, CXCR4, play a major role in migration, retention, and development of hematopoietic progenitors in the bone marrow. During steady-state hematopoiesis, CXCR4/SDF-1 interaction restricts hematopoietic stem progenitor cells in marrow and disruption of the SDF-1/CXCR4 axis leads to their egress into circulation. However, biological responses to SDF-1 are rapidly attenuated by overlapping mechanisms that include peptide degradation by cell surface proteases, receptor uncoupling from heterotrimeric G-proteins and receptor endocytosis. It is known that phosphorylation of G-protein coupled receptors (GPCRs) by several protein kinases including serine-threonine kinase, protein kinase C (PKC), can result in receptor desensitization. This prompted us to investigate whether the role of serine- threonine phosphatase in the regulation of SDF-1 induced responses of CD34+ cord blood (CB) cells. To investigate the role of serine- threonine phosphatase we evaluated the effect of okadaic acid, a specific serine-threonine phosphatase inhibitor, on SDF-1 induced chemotaxis and adhesion of CD34+ cells from cord blood. Pre-incubation of CD34+ CB cells with okadaic acid (100–1000nM) significantly reduced SDF-1 directed chemotaxis and adhesion of CD34+ CB cells. This correlated with an increase in PKC phosphorylation. Although primary SDF-1 induced calcium flux in CD34+CB cells was unaffected by okadaic acid, if the cells were pretreated with SDF-1 and then stimulated with SDF-1, calcium flux was significantly less in CD34+CB cells pretreated with okadaic acid compared to untreated cells. Further, confocal microscopy was used to demonstrate the co-localization of serine threonine phosphatase and PKC. Using antibodies specific to PP2A catalytic subunit (PP2Ac) and various classes of PKC super family, it was observed in unstimulated CD34+ CB cells PP2Ac was mainly localized in nucleus and some phosphor-PKC-delta was detected in the cytoplasm. However, upon SDF-1 stimulation, co-localization of PP2Ac and phospho-PKC-delta was observed on the membrane of CD34+CB cells. These results indicate that serine-threonine phosphatase regulate SDF-1 mediated responses in CD34+CB cells and may play an important role in the ability of hematopoietic stem progenitor cells to continually respond to SDF-1.
LIF-LIF-R and SDF-1-CXCR4 Axes Regulate Overlapping and Complementary Steps of Metastasis of Rhabdomyosarcoma - Implication for Developing Better Antimetastatic Therapies.
Authors: Miekus Kasia , Wysoczynski Marcin , Reca Ryan , Jolanta Gozdzik , Salvatore Bertolone J. , Janowska-Wieczorek Anna , Ratajczak Mariusz Z. 
Published: April 2020

Abstract
Rhabdomyosarcoma (RMS) and skeletal muscle-derived tumors frequently infiltrate bone marrow (BM). We have demonstrated that the stromal-derived factor (SDF)-1-CXCR4 receptor (Blood2002;100:2597) and Leukemia Inhibitory Factor (LIF)-LIF- receptor (LIF-R) axes play a pivotal role in RMS metastasis to BM. In this study performed on primary patient material (n=23) and human alveolar and embryonal RMS cell lines, we compared various prometastatic effects of both axes. First, we found that both motomorphogens (LIF and SDF-1) and their corresponding receptors (LIF-R and CXCR4) are upregulated in hypoxic conditions. Second, both functional receptors were expressed on RMS cells; however, the expression of LIF-R in contrast to CXCR4 was PAX3-FKHR-independent and did not correlate with the alveolar rhabdomyosarcoma (ARMS) phenotype. Both ligands stimulated similar signaling pathways (MAPKp42/44 and AKT) in RMS cells and similarly stimulated directional chemotaxis. However, SDF-1 affected the spontaneous motility of RMS cells to a higher degree than LIF and strongly upregulated the secretion of MMPs and VEGF. In contrast, LIF enhanced the resistance of RMS cells to cytostatics (e.g., etoposide). To compare the biological effects of both axes we focused on the ARMS cell line RH30 (highly responsive to SDF-1 and LIF) and selected cells that responded to SDF-1 but not LIF (RH30-S) and to LIF but not SDF-1 (RH30-L) by using repetitive chemotaxis to SDF-1 or LIF. We found that RH30-L cells, as compared to RH30-S cells, responded worse in chemotactic assay to BM-derived conditioned media; however, they adhered much better to BM stroma. When both cell populations (RH30-S and RH30-L), together with the parental RH30 cells, were tested in vivo for their seeding potential in various organs in RAG2 immunodeficient mice, we found that RH30-L cells seeded better to BM, liver and lymph nodes than RH30-S cells. More important, the metastatic potential of RH30 cells was significantly reduced only when the inhibitors of both receptors, (T140 for LIF-R and gp130 blocking antibody for CXCR4) were employed together. Hence, since RMS cells respond to more than one chemoattractant, strategies aimed at targeting a single factor-receptor axis would be ineffective. Targeting of the LIF-LIF-R axis, along with the SDF-1-CXCR4 axis, could thus become a new, more effective antimetastatic strategy to inhibit RMS metastasis.
Sodium Nitrite Increases Regional Blood Flow in Patients with Sickle Cell Disease.
Authors: Mack A. Kyle , Machado Roberto F. , Sachdev Vandana , Gladwin Mark T. , Kato Gregory J. 
Published: April 2020

Abstract
Patients with sickle cell disease have decreased nitric oxide bioavailability, and studies from several groups have confirmed a blunted response to various NO donors in humans and mice with sickle cell disease. Recently published studies show that nitrite induces vasodilation in humans, apparently mediated by conversion of nitrite to NO.
This study is designed to determine the potential therapeutic effect of intra-arterial nitrite infusion to restore nitric oxide dependent blood flow in the forearms of patients with sickle cell disease.
Venous occlusion strain gauge plethysmography is used to measure the change of forearm blood flow in patients with sickle cell disease, before and after sequential brachial artery infusions of increasing doses of sodium nitrite. In addition, NO responsiveness before and after nitrite infusion is measured by test doses of the NO donor sodium nitroprusside (SNP). Six patients have completed the study and enrollment is continuing.
These data indicate that nitrite promotes regional blood flow in patients with sickle cell disease, albeit with a blunted response compared to our healthy control subjects, in whom we previously have found increased blood flow up to 187% with comparable dosing. The significant but blunted response is consistent with the state of nitric oxide resistance to NO donors that has been seen by several groups in patients and mice with SCD. Additionally, we find in these patients that nitrite partially restores SNP responsiveness, with baseline maximal SNP responses more than doubling on average following nitrite infusion, although this finding is preliminary. No adverse effects of nitrite were seen in these six patients.
Our early results support a role for nitrite as an NO donor effective in restoring NO-dependent blood flow in patients with sickle cell disease. Additional translational studies are warranted to evaluate the therapeutic effects of systemic nitrite dosing.
Table 1. Forearm Blood Flow Response to Nitrite Infusion Nitrite Dose (micromole/min) Sickle Cell Disease Historical Controls P&lt; .0001 (ANOVA) 0.4 5 +/−7.2% N=6 22 +/−3.2% N=10 4 15 +/− 11% N=6 Not infused 40 49 +/− 8.9% N=6 187 +/− 16%N=18 Table 2. Nitrite Effect on Nitroprusside Responsiveness SNP Dose (micrograms/min) Pre-Nitrite Post-Nitrite P= .02 (RM-ANOVA) N=6 0.8 +21 +/− 5.6% +33 +/− 8.3% 1.6 +15 +/− 5.9% +62 +/− 15.1% 3.2 +29 +/− 6.3% +67 +/− 11.5%
Berkeley Sickle Mice Demonstrate CD8- and NK1.1-Dependent Increased Rejection of Allogeneic Hematopoietic Stem Cell Transplants.
Authors: Kean Leslie , Hamby Kelly , Perry Jennifer , Larsen Christian , Archerq David 
Published: April 2020

Abstract
While hematopoietic stem cell transplantation (HSCT) represents the only curative therapy for sickle cell disease, sickle patients undergoing HSCT face many complications, including an increased risk of graft rejection compared to non-sickle patients.
We have used the Berkeley sickle mouse model to study the potential mechanisms underlying this increased risk of rejection. Using a CD28/CD40 costimulation-blockade-based non-myeloablative HSCT regimen, we transplanted Berkeley sickle mice with fully allogeneic SJL bone marrow. While the vast majority (&gt;85%, n=25) of control C57BL/6 animals became stably chimeric and immunologically donor-tolerant with this transplant regimen, sickle mice were much more prone to reject the transplant (~20% graft acceptance, n=25). Both CD8+ cells and NK1.1+ cells were found to contribute to this rejection, as depletion of either of these cell populations led to a marked increase in the percent of engrafted mice (&gt;85% graft acceptance, n=15–25), while depletion of CD4+ cells led to the opposite effect, with 0% (n=25) animals engrafted in this depletion cohort.
The increased propensity of HSCT rejection in the Berkeley sickle mice may, in part, be explained by the presence of increased numbers of donor-reactive T cells (5–10-fold compared to C57BL/6 controls) in naïve sickle mice, despite their lack of exposure to donor antigens, and their housing in a Specific-Pathogen-Free environment. We speculate that these increased numbers of anti-donor T cells may occur as a result of heightened inflammation in the context of active sickle cell disease, which could lead to increased expansion and persistence of a T cell repertoire containing anti-donor heterologous T cell immunity. This heterologous immunity may have a profound effect on the success of HSCT for sickle cell disease, especially when non-myeloablative regimens are employed.
Electron Paramagnetic Resonance Study of Cell-Free Hemoglobin in Sickle Cell Disease: Potential Antioxidant Role of Haptoglobin.
Authors: Piknova Barbora , Gladwin Mark T. , Hillery Cheryl A. , Hogg Neil 
Published: April 2020

Abstract
It has previously been shown that red blood cell-free oxyhemoglobin (oxyHb) can affect endothelial function in Sickle Cell Disease (SCD) by virtue of its NO scavenging properties (Reiter et al, Nat Med, 2002). This reaction may have down-stream consequence via formation of metHb which has been demonstrated to have pro-oxidant properties and can oxidize low-density lipoprotein in vitro. In this study we have examined the fate of metHb in SCD vs normal plasma by examining the characteristic single line EPR signature of metHb in the g = 6 region. We show that the EPR signature of metHb differs in SCD compared with normals and exhibits a split EPR line indicative of a more rhombic heme geometry (See Figure).
Figure Figure
Addition of purified metHb to SCD plasma results in a conversion of the single line EPR spectrum to the rhombic form. By addition of hemin and hemoglobin to plasma constituents we have determined that the rhombic EPR spectrum is consistent with heme bound to serum albumin. In addition, immunoprecipitation of serum albumin from SCD plasma with EPR analysis of the IP fraction revealed the presence of albumin associated metHb. Interestingly, the transfer of heme from metHb to albumin is accelereated by the presence of low-density lipoprotein and inhibited by the addition of haptoglobin suggesting that plasma components can modulate heme release from metHb and that the lack of haptoglobin in SCD plasma allowed the transfer of heme from metHb to albumin. To confirm this we added metHb to SCD plasma in the presence and absence of haptoglobin and observed that the addition of haptoglobin prevented conversion of the metHb spectrum to the albumin associated split (rhombic) species. From these studies we conclude that plasma haptoglobin not only binds hemoglobin but also limits heme release from metHb. To examine potential oxidative consequences of this effect, we incubated LDL with metHb in the presence and absence of haptoglobin. Haptoglobin inhibited LDL oxidation in a dose-dependent manner. Interestingly, the 1-1 isoform of haptoglobin was much more effective than the 2-2 isoform, in agreement with published studies on the efficacy of hemoglobin binding to the two haptoglobin varieties. Additionally, we have measured levels of 8-isoprostanes in the plasma of SCD patients as an index of lipid oxidation and show that 8-isoprostane levels are significantly elevated in SCD patients (295 209 pg/ml, mean S.D., n= 13, vs. 69 37 pg/ml, mean S.D. n= 5 for normal controls). In conclusion, these studies provide evidence that the saturation of the haptoglobin clearance mechanisms in hemolytic disorders such as SCD can not only affect the NO-axis of endothelial function due to increases in cell-free hemoglobin, but can also lead to altered heme metabolism leading to lipid oxidation and formation of pro-inflammatory lipids which have the potential to alter both endothelial and red cell function.