bluuebunny/crossref_metadata_2025_split huggingface dataset:
Thrombopoietin-Mediated Activation of the mTOR/S6K/4E-BP Signaling Pathway Is Required for Proliferation in Megakaryocyte Progenitors.
Authors: Drayer Lyndsay , Olthof Sandra , Vellenga Edo 
Published: October 2019

Abstract
Translational regulation plays a central role in cell proliferation, survival and cell differentiation through activation of the target of rapamycin (mTOR) signaling pathway. mTOR controls the phosphorylation status of proteins involved in initiating translational control, including ribosomal S6 kinase (S6K) and eukaryotic translation initiation factor 4E-binding protein (4E-BP). Recently, the mTOR and phosphoinositide 3-kinase (PI3-K) pathways have been linked through the tumor suppressor complex TSC1/2. The PI3-K target PKB inactivates the TSC1/2 complex which acts as a GAP for the Ras homologue Rheb to suppress mTOR signaling. As the regulation of cell number and cell size are important factors during megakaryopoiesis, we investigated the role of mTOR signaling in thrombopoietin (TPO) induced proliferation and differentiation in primary human megakaryocyte progenitors and in megakaryoblastic MO7e cells. Preincubation of isolated CD34+ cells, primary cultured CD61+ cells and MO7e cells with the mTOR inhibitor rapamycin (10 nM) resulted in highly specific inhibition of TPO-mediated 4E-BP1 (S65) phosphorylation, S6K (T389) phosphorylation and its substrate S6 (S235/236), without affecting PKB (S473) phosphorylation. Activation of the mTOR signaling pathway by TPO was dependent on the PI3-K pathway as LY294002 (10 μM) inhibited phosphorylation of 4E-BP1, S6K and S6. Treatment of MO7e cells with rapamycin inhibited TPO-induced proliferation and cell cycling by reducing cells in S-phase and blocking cells in G1. Rapamycin did not induce apoptosis as measured by cells in sub-G0 phase and by Annexin V expression. Suspension cultures of CD34+ cells treated with rapamycin resulted in a 2.3-fold reduction in overall cell proliferation (p=0.01) and a reduction in the percentage of CD61+ megakaryocytic cells (55.2±7.93 vs 35.0±5.42, p=0.08) generated after 7 days. The mean fluorescence intensity of CD61 and CD42 expressing cells was however not decreased. In addition, polyploidisation levels of the CD61 expressing cells cultured in the presence of rapamycin were not decreased, indicating rapamycin inhibited megakaryocyte proliferation, not differentiation. Further analysis revealed that transforming growth factor β1 (TGF-β1), which inhibits proliferation of megakaryocyte progenitors, downregulated TPO-induced S6K/S6 phosphorylation. Concluding, we have shown that the mTOR pathway is activated by TPO and plays a role in regulating proliferation in megakaryocyte progenitors. Part of the effect of the PI3-K/PKB and TGF-β pathways in regulating proliferation may be mediated by the mTOR/S6K/4E-BP1 signaling pathway.
Same Day Dosing of Pegfilgrastim in Elderly Patients Receiving Fractionated Dose Chemotherapy.
Authors: Watt Larry Y. , Redei Istvan , Levin Robert D. , Granick Joel , Neelam Rakhshanda , Musick Robert E. 
Published: October 2019

Abstract
Background: We have previously reported that same day dosing (SDD) of pegfilgrastim (PG) did not result in an increased incidence of negative outcomes as compared to filgrastim (G) administered the next day. (Watt et al. Pharmacotherapy. 2003;23:406. #105). Age (≥ 65 years) is known to be a risk factor for febrile neutropenia in patients undergoing myelosuppressive chemotherapy.
Purpose/Methods: This study aims to assess the efficacy and safety of SDD of PG among older cancer patients for severity of neutropenia (grade 4), infection/neutropenia- related hospitalization, incidence of delayed administration (or dose reduction) of chemotherapy or any unplanned MD visits due to leukopenia (table). G administered subsequent to chemotherapy served as the control group. Patients ≥ 65 years with solid tumors who received fractionated dose chemotherapy at our institution between January 2001 and March 2004 were reviewed retrospectively. Patients who received chemotherapy initially at substandard doses were excluded.
Results: Patient demographics indicated that the two groups were evenly matched, with similar mean baseline absolute neutropenic counts (ANC). Distribution of cancer diagnoses is as follows: PG: breast (7), lung (8), GI (18) and others (2); G: breast (5), lung (9), GI (7) and others (4). Twenty-six (87%) and 21 (84%) patients had stage IV cancer in the PG and G groups, respectively. The mean ANC nadirs for PG and G were 2790±2190 cells/mm³ and 1820±1930 cells/mm³, respectively (p=0.01). For the outcome endpoints, although certain trends seemed to favor SDD of PG, none of the odd ratios (OR) performed reached statistical significance. Doses of PG and G were generally well-tolerated by all patients.
Conclusion: Concurrent administration of PG showed safety and efficacy at least comparable to G in elderly patients receiving fractionated dose chemotherapy. Such administration schedule has the potential to further simplify the outpatient management of chemotherapy-induced neutropenia, providing the needed convenience for elderly patients as well as caregivers. However, further prospective study is warranted.
PG G p-value; OR (95% CI) data were analyzed based on cycles No. patients 30 25 No. cycles 59 54 Age (range) 68.8 (65–79) 68.3 (65–72) Gender (female) 18 (60%) 15 (60%) ANC before chemo±SD(cells/mm³) 4530±1850 4790±2600 p=0.539 ANC nadir±SD (cells/mm³) 2790±2190 1820±1930 p=0.01 Severe Neutropenia (grade IV) 9 (15%) 15 (28%) OR=0.47; (0.19, 1.18) Unplanned MD visit 7 (12%) 3 (5.6%) OR=2.28; (0.56, 9.34) Chemo delayed/dose reduced 9 (15%) 11 (20%) OR=0.70; (0.27, 1.86) Hospitalization 7 (12%) 5 (9.3%) OR=1.32; (0.39, 4.44)
Loss of Runx1 Perturbs Adult Hematopoiesis and Is Associated with a Myeloproliferative Phenotype.
Authors: Growney Joseph D. , Shigematsu Hirokazu , Li Zhe , Lee Benjamin H. , Adelsperger Jennifer , Rowan Rebecca , Curley David P. , Akashi Koichi , Williams Ifor R. , Speck Nancy A. , Gilliland D. Gary 
Published: October 2019

Abstract
Homozygous loss of function of Runx1 during murine development results in an embryonic lethal phenotype characterized by a complete lack of definitive hematopoiesis. In light of recent reports of disparate requirements for hematopoietic transcription factors during development as opposed to adult hematopoiesis, we employed a conditional gene targeting strategy to effect loss of Runx1 function in adult mice. In contrast with the critical role of Runx1 during development, Runx1 was not essential for hematopoiesis in the adult hematopoietic compartment, although there were a number of significant hematopoietic abnormalities observed. Runx1 excision had significant lineage specific effects on B- and T-cell maturation, as well as pronounced inhibition of common lymphocyte progenitor production. Runx1 excision also resulted in inefficient platelet production. Of note, Runx1 deficient mice developed a mild myeloproliferative phenotype characterized by an increase in peripheral blood neutrophils, an increase in myeloid progenitor populations, and extramedullary hematopoiesis comprised of maturing myeloid and erythroid elements. These findings indicate that Runx1 deficiency has markedly different consequences during development compared with adult hematopoiesis, and provides insights into the phenotypic manifestations of Runx1 deficiency in hematopoietic malignancies.
Prognostic Significance of CD20 in Children with B-Precursor Acute Lymphoblastic Leukemia.
Authors: Jeha Sima , Cheng Cheng , Sandlund John , Ribeiro Raul , Razzouk Bassem , Rubnitz Jeffrey , Hijiya Nobuko , Howard Scott , Behm Fred , Pui Ching-Hon 
Published: October 2019

Abstract
CD20 expression is associated with inferior survival in adults with ALL. Preliminary reports indicate that regimens incorporating rituximab improve outcome in this subgroup. We analyzed the prognostic impact of CD20 in 353 children with B-cell precursor ALL treated between 12/20/91 and 5/17/99 on three consecutive St. Jude Total Therapy studies. CD20 expression (>20%) was found in 169 patients (48%). Expression was higher in patients between 1 and 10 years (51% of 252 patients), as compared to those less than 1 year of age (7% of 15 patients) or more than 10 year old (43% of 86 patients), p=0.0008. African American patients were more likely to express CD20 (66%), as compared to Caucasians (45%) or other ethnic groups (45%), p=0.047. None of 14 patients with MLL-AF4 expressed CD20. There was no association between CD20 expression and E2A-PBX, TEL-AML1, ploidy, WBC at diagnosis, or gender. In contrast to the experience in adult ALL, our patients with CD20 expression tended to have a better treatment outcome than those without the expression: 5-year EFS 84% ± 2.9% versus 78% ± 3.1% (p=0.08); 5-year overall survival 88% ± 2.5% versus 83% ± 2.8% (p=0.13). This data suggest that CD20 expression is not associated with inferior outcome in pediatric patients treated with contemporary regimens.
Generation and Analysis of Target Genes Libraries of the Erythropoietic Transcription Factor GATA-1.
Authors: Katsantoni Eleni Z. , Horsman Sebastiaan , Moorhouse Michael J. , de Jager Victor C.L. , van der Spek Peter , Grosveld Frank , Strouboulis John 
Published: October 2019

Abstract
GATA-1 is essential for the generation of the erythroid, megakaryocytic, eosinophilic and mast cell lineages. It acts as an activator and repressor of different target genes. In erythroid cells it represses cell proliferation and early hematopoietic genes while activating erythroid genes. In order to elucidate further the role of GATA-1 we applied an in vivo tagging methodology for the specific, quantitative biotinylation of this factor in mammalian cells (de Boer et al., 2003). We applied this method for identification of novel target genes of GATA-1 by performing pull-downs of crosslinked chromatin using streptavidin. We have also performed chromatin immunoprecipitations, where crosslinked chromatin was immunoprecipitated with antibodies against GATA-1, thus enriching for sequences bound in vivo by this factor in the immunoprecipitated DNA. Libraries of in vivo bound DNA targets were generated and a number of clones were sequenced. In order to facilitate the bioinformatics analysis of these libraries we generated TF Target Mapper (Transcription Factors Target Mapper). This is a BLAST search tool that allows rapid extraction of annotated information on genes around each hit and combines sequence cleaning/filtering, pattern searching and comparisons of the output list of genes or gene ontology IDs with user implemented lists. This tool was successfully applied to analyze sequences bound in vivo by the transcription factor GATA-1 and efficiently extracted information on genes around ChIPed sequences, thus identifying known and potentially novel GATA-1 gene targets. Using TF Target Mapper, 95 sequences were processed and annotated information on 372 genes 50kb upstream and downstream of each hit was extracted in 27 minutes. Among these genes, known targets of GATA-1, such as α-globin and ζ-globin, were readily identified by comparing to a list of known GATA-1 targets. This work is anticipated to provide a genome wide map of GATA-1 target genes in vivo. The identification of target genes and elucidation of their functions in hematopoiesis will allow the construction of complex transcriptional pathways that control lineage commitment and differentiation decisions.
Ideal (IBW) Rather Than Actual (ABW) Body Weight Should Be Used To Calculate Cell Dose in Allogeneic HSCT.
Authors: Singhal Seema , Evens A. , Frankfurt O. , Gordon L. , Meagher R. , Tallman M. , Williams S. , Winter J. , Grinblatt D. , Kaminer L. , Mehta J. 
Published: October 2019

Abstract
Graft CD34+ cell content based on ABW affects outcome after conventional allografts (Singhal et al. BMT2000;26:489–96). Engraftment after autologous (Ali et al. BMT2003;31:861–4) and allogeneic (Cilley et al. BMT2004;33:161–4) HSCT correlates better with CD34+ cell dose based on IBW than ABW. 63 patients (27–66 y, median 52) underwent submyeloablative HSCT from HLA-matched sibling (n=37), 10/10 allele-matched unrelated (n=19), or 1-locus/allele mismatched (n=7) donors for hematologic malignancies after 100 mg/m2 melphalan with (n=42; no prior autograft) or without (n=21; prior autograft) 50 mg/kg cyclophosphamide. GVHD prophylaxis comprised cyclosporine-mycophenolate with HLA-matched sibs and tacrolimus-mycophenolate with the rest. G/GM-CSF were not used. Supportive care was uniform. ABW and IBW values were 45–147 kg (median 79) and 52–85 kg (median 67) respectively. The ABW-IBW difference was −24% to +133% (median +16%); 9 patients were >5% underweight and 41 were >5% overweight. Chemotherapy doses were based on ABW for underweight patients, and adjusted weight for overweight (IBW + 25% of the ABW-IBW difference). The target CD34+ cell dose was 2–8 x106/kg IBW; preferably >6 and ≤ 8 based on prior findings (Singhal et al. ASH 2004). The CD34+ cell dose infused was 1.4–11.8 (median 5) by IBW and 1.2–9.3 (median 4.5) by ABW. The CD3+ cell dose (108/kg) was 0.9–14.9 (median 3) by IBW and 0.7–19.7 (median 2.7) by ABW. The 2-y cumulative incidence of relapse and transplant-related mortality (TRM) was 55% and 24% respectively. The 2-y probabilities of overall (OS) and disease-free (DFS) survival were 35% and 21% respectively.
CD34+ cell dose by IBW CD34+ cell dose by ABW >6 and ≤ 8 (n=11) 6 or >8 (n=52) ≤ P >6 and ≤ 8 (n=8) 6 or >8 (n=55) ≤ P 3-y OS 61% 27% 0.040 31% 25% 0.22 3-y DFS 41% 13% 0.043 0% 14% 0.53 1-y TRM 0% 27% 0.029 0% 25% 0.090 1-y Relapse 45% 48% 0.34 63% 47% 0.70 CD3+ cell dose by IBW CD3+ cell dose by ABW <3 (n=31) 3 (n=32) ≥ P <3 (n=36) 3 (n=27) ≥ P 3-y OS 34% 18% 0.032 27% 24% 0.54 3-y DFS 24% 4% 0.043 18% 7% 0.58 1-y TRM 10% 35% 0.008 17% 30% 0.12 1-y Relapse 52% 44% 0.66 53% 41% 0.67
As the tables show, the CD34+ and CD3+ cell doses by IBW affected OS, DFS and TRM significantly. When ABW was used with the same numeric thresholds, the differences were less marked and not significant. The figures show the effect of the CD34+ cell dose on DFS and the CD3+ cell dose on OS.
Figure Figure Figure Figure
Other cell dose thresholds based on ABW were also not found to be significant (data not shown). Based on these findings and our prior work on engraftment, we suggest using IBW rather than ABW to calculate cell doses for HSCT; for statistical analyses and for clinical practice if a specific cell dose is being targeted.
Culture-Expanded Human Bone Marrow Stromal Stem Cells Organize Functional Bone Marrow Niches In Vivo.
Authors: Miura Yasuo , Gao Zhigang , Miura Masako , Seo Byoung-Moo , Sonoyama Wataru , Chen WanJun , Gronthos Stan , Zhang Li , Shi Songtao 
Published: October 2019

Abstract
Bone marrow stromal stem cells (BMSSCs) are mesenchymal stem cells that are capable of differentiating into osteoblasts, chondrocytes, adipocytes, muscle cells and neural cells. Upon in vivo transplantation, BMSSCs form bone and associated hematopoietic marrow elements. However, the functional role of BMSSC-associated bone marrow is still unknown. In this study, we demonstrated that human BMSSCs organized ectopic bone marrow niche microarchitecture that contained hematopoietic progenitors and multiple lineages of cells including myeloid, lymphoid, erythroid and megakaryocytic cells originated from recipients. Significantly, transplantation of the ectopically generated bone marrow cells can rescue lethally irradiated mice with successful hematopoietic engraftment, suggesting a therapeutic potentiality of human BMSSC-organized hematopoietic progenitor cells. In addition, systemically administrated bone marrow cells derived from long bones of donor mice homed to BMSSC-associated ectopic bone marrow niche microenvironments. These data demonstrate that BMSSC-organized ectopic bone marrow has functional analogy to physiological bone marrow. Mechanistically, platelet-derived growth factor (PDGF)-BB was found to promote hematopoiesis in the BMSSC transplants through an up-regulated expression of β-catenin. Conversely, inhibition of PDGF signaling in BMSSCs by PDGF receptor β siRNA blocked hematopoiesis and osteogenesis in the BMSSC transplants. Moreover, the BMSSC-organized ectopic bone/marrow structure could be utilized as an organ to be re-transplanted into secondary recipient mice to deliver hematopoietic cells in the recipient’s circulation system, implying a therapeutic potential of transplanting bone/marrow organ system containing hematopoietic stem cell niches. In summary, these evidences demonstrate that regeneration of BMSSC-organized functional bone marrow niches contain hematopoietic progenitor/stem cells and therefore provide promise for clinical therapy.
Enhancing the Therapeutic Potential of an Anti-Leukemic Peptide.
Authors: Palermo Christine M. , Wimley William C. , Hemenway Charles S. 
Published: October 2019

Abstract
Despite ongoing success in the treatment of childhood acute lymphoblastic leukemia (ALL), patients harboring translocations involving the genetic locus 11q23 continue to have a poor prognosis. The majority of 11q23 translocations result in the formation of a functional fusion protein consisting of the N-terminus of MLL fused to the C-terminal portion of one of more than 30 fusion partners. This translocation results in a functional chimeric protein critical for leukemogenesis. Recently, our lab has identified an interaction between two common MLL fusion partners, AF4 and AF9. Through a series of mapping experiments we identified a small region of human AF4 to be sufficient for its interaction with AF9. Based on these studies, a synthetic peptide (PFWT) that mimics the AF9 binding site on AF4 was developed. Treatment of leukemia cells that express the MLL-AF4 protein with PFWT results in apoptosis with no observable affects on CD34+ hematopoietic stem cells, suggesting the AF9-AF4 interaction is a promising chemotherapeutic target. To improve upon the therapeutic potential of PFWT, we developed a high-throughput enzyme-linked colorimetric assay to identify peptidomimetics that block the AF9-AF4 interaction. A combinatorial peptide library was synthesized in which each position of the 10-mer sequence was substituted with either the α- or corresponding β-amino acid. β-Amino acids which are similar to α-amino acids but contain an additional carbon in their backbone were chosen because of their resistance to proteases (210= 1024 possible unique sequences). To date, 30 of the peptides screened compare favorably with PFWT for disrupting the AF4-AF9 interaction. Sequencing of the peptides by MS/MS revealed substitutions at the N- and C-terminal ends are well tolerated. In addition, peptides can incorporate as many as three β-amino acids and still retain biological activity. These data are important for establishing a sequence with improved pharmacokinetic properties as compared to PFWT and serve as the first step in our design towards an optimal peptide sequence for drug development. They also validate the utility of a high-throughput assay system for drug screening. Future studies for the identified peptides include determining their biological half-lives, AF9 binding affinities, and ability to induce apoptosis in leukemia cells.
Dexmethasone Down-Regulates Stromal Cell-Derived Factor-1 Production in Bone Marrow Stromal Cells: Implications in Myeloma Cell Biology.
Authors: Kim Seong-Woo , Hwang Jin-Hee , Yun Hwan-Jung , Kim Samyong , Jo Deog-Yeon 
Published: October 2019

Abstract
Stromal cell-derived factor-1 (SDF-1) plays a role in the homing of myeloma cells to bone marrow. In addition, SDF-1 modestly enhances the proliferation of myeloma cells and inhibits Dexmethasone (Dex)-induced apoptosis of the cells. Dex is currently used to treat multiple myeloma, based on its apoptic effects. In this study, we investigated the regulatory effects of Dex on SDF-1 production in bone marrow stromal cells (BMSCs) and on CXCR4 expression in myeloma cells. As previously reported, it was evident that primary myeloma cells (CD138+ cells obtained from patients with multiple myeloma) and Dex-resistant myeloma cell line RPMI8226 expressed CXCR4 and responded to SDF-1, resulting in chemotaxis. SDF-1 modestly stimulated the proliferation of primary myeloma cells and RPMI8226 cells and protected the cells from Dex-induced apoptosis. Human umbilical vein endothelial cells transduced with the SDF-1 gene using adenoviral vectors better supported the formation of cobblestone areas of primary myeloma cells and RPMI8226 cells in co-culture, similar to hematopoietic progenitor cells; this was blocked by pretreating the myeloma cells with pertussis toxin, indicating that SDF-1 plays a critical role not only in migration of the cells underneath the SDF-1-producing stromal cells but also in proliferation of the cells in contact. Dex up-regulated CXCR4 expression in RPMI8226 cells; however, its regulatory effects on CXCR4 in primary myeloma cells differed among patients. RT-PCR and Northern blot analyses revealed that Dex down-regulated SDF-1 mRNA expression in both primary BMSCs and murine stromal MS-5 cells in a dose-dependent manner. Western blot analysis and ELISA assay confirmed that Dex inhibited SDF-1 production in BMSCs. Furthermore, Dex inhibited cobblestone area formation of RPMI8226 cells in co-culture with MS-5. Interestingly, Dex up-regulated CXCR4 mRNA expression and cytoplasmic CXCR4 in BMSCs. These results indicate that Dexamethasone induces the down-regulation of SDF-1 production in BMSCs, which might mediate, at least in part, its anti-myeloma effects in vivo.