bluuebunny/crossref_metadata_2025_split huggingface dataset:
Injury to the Thymic Niche for DN2/DN3 Developing T Cells Impairs Reconstitution.
Authors: Prockop Susan , Nikolopoulos Sotiris , Myers Aaron , Giancotti Filipo , Petrie Howard T. , O’Reilly Richard J. 
Published: April 2020

Abstract
Despite recovery of most hematopoietic functions, prolonged defects in generating functional T lymphocytes is a common occurrence after T cell depleted bone marrow transplant. While the mechanisms of these defects have not all been elucidated, contributing factors include age, T cell depletion of the graft, therapy with radiation and cytotoxic agents, and graft versus host disease (GvHD). We have designed an in vivo functional assessment of the ability of thymic stroma to support de novo T lymphocyte development. Mice deficient for the alpha chain of the IL-7 receptor (IL7Rα−/−) support robust thymic reconstitution after transplant of limited numbers of congenic precursors. We demonstrated that this capacity for reconstitution of immunodeficient strains depends on the paucity of specific endogenous precursors (DN3) cells in the IL7Rα−/− thymus and reflects the presence of functionally normal but empty stromal niches in this immunodeficient strain. We have proceeded to demonstrate that a variety of chemotherapeutic agents as well as aging, impair the ability of IL7Rα−/− thymic stroma to support de novo T cell development. Some agents allow donor chimerism in the thymus, but not rescue of the hypocellularity (eg cyclophosphamide) while others do not affect reconstitution (eg fludarabine). Multi-agent regimens have been administered and in some instances demonstrate an additive detrimental impact on thymic reconstitution. For several agents, damage has been localized to specific stromal niches by isolating changes in lymphoid subsets and stromal keratin expression. Decreased availability of the stromal niche for DN3 progenitors is associated with a decreased frequency of DN3s and an absolute block in recipient IL7Rα−/− T cell development. In addition, RNA from treated and untreated thymic stromal cells has been used to evaluate the gene expression pattern in thymic stroma of IL7Rα−/− mice treated with cytotoxic agents. In one example to be presented we find decreased thymic reconstitution in mice treated with Busulfan with sustained changes in stromal elements. These findings are consistent with sustained damage to thymic stromal cells. Among other changes, busulfan leads to decreased expression of laminin 5 by cortical thymic epithelial cells. The integrin heterodimerα6β4 is a binding partner for laminin 5 and is expressed uniformly by DN2 thymocytes. The significance of laminin 5/α6β4 signaling during T cell development was assessed using mice with a targeted mutation in the integrin β4 signaling domain. In these experiments mutant fetal liver was used to create hematopoietic chimeras and evaluate T cell development. Our studies provide insight into the nature of damage to thymic stroma by cytotoxic regimens and an understanding of the effect of this damage on subsequent immune reconstitution.
Phase III Study of Denileukin Diftitox (ONTAK®) To Evaluate Efficacy and Safety in CD25+ and CD25- Cutaneous T-Cell Lymphoma (CTCL) Patients.
Authors: Negro-Vilar Andres , Dziewanowska Zofia , Groves Eric , Lombardy Elyane , Stevens Victor 
Published: April 2020

Abstract
Denileukin diftitox (ONTAK®) is a genetically engineered fusion protein composed of the enzymatically active domain of diphtheria toxin and the full length sequence of interleukin-2 (IL-2), designed to target malignancies expressing the IL-2 receptor. The drug is approved for the treatment of CTCL in patients expressing the CD-25 component of the IL-2 receptor. L4389-14 is a phase III study designed to further evaluate the efficacy and safety of denileukin diftitox (DD) in distinct subgroups of CTCL patients. The study met its accrual goal of 90 patients and included three subgroups of patients: 1) CD25 (+) patients that crossover from a placebo course of treatment in a companion study (L4389-11) and had progressed or failed to respond during an 8-course placebo treatment (N=34); 2) CD25 (−) patients (N=36) and 3) CD25 (+) patients that had previously been treated with DD, responded, and subsequently relapsed (retreatment group, N=22). Patients entered the study at stages Ia to III and received DD at a dose schedule of 18mcg/Kg/day by IV infusion once daily for 5 days every 3 weeks for up to 8 cycles. Efficacy of treatment was assessed based on tumor burden, lymph nodes, lymphocyte count, and patient status (PGA) at every cycle, beginning on cycle 2. A response assessment required confirmation in two subsequent cycles. Responses were evaluated by an independent Drug Evaluation Review Committee. Assessment of activity of DD across the 3 groups based on an analysis of the data is shown in the table below. Patient demographics were consistent across subgroups and representative of a general CTCL population. Disease status at baseline was Stage IIa or earlier 66% of patients and stage IIb or higher 34% of patients. About 46% of patients presented with mild to severe erythroderma. Adverse events were similar to those previously observed with ONTAK. Serious adverse events of ≥5% incidence were nausea (9%), vomiting (5%), capillary leak syndrome (5%), pyrexia (9%) and infections (10%). The results of this large phase III trial showed very consistent efficacy of denileukin diftitox across treatment-naïve CD25 (+) and CD25 (−) patients, as well as in patients undergoing retreatment with DD. Duration of response and progression free survival were also quite favorable across the different CTCL subgroups.
Response Assessment CD25 (+) Placebo Crossover CD25 (−) CD25 (+) Retreatment N = 34 36 22 ORR (CR/CCR/PR) 47.1% 30.6% 36.4% CR/CCR 17.6% 8.3% 9.1% PR 29.4% 22.2% 27.3% SD 29.4% 44.4% 31.8% PD 20.6% 25.0% 31.8% Duration of Response (days) 820 340 274 Progression Free Survival (days) 870 Not reached 429
The Bcl-2 Protein Family Is Essential for Platelet Survival In Vivo.
Authors: Mason Kylie D. , Carpinelli Marina R. , Collinge Janelle E. , Hilton Adrienne A. , Fletcher Jamie I. , Roberts Andrew W. , Metcalf Donald , Huang David C.S. , Kile Benjamin T. 
Published: April 2020

Abstract
Platelets are small, anuclear cytoplasmic fragments that play an essential role in blood clotting and hemostasis. They are produced by megakaryocytes: large, polyploid cells that reside primarily in the bone marrow. Once shed into the blood stream, platelets are consumed either by their participation in hemostatic processes, or their eventual destruction by the reticulo-endothelial system. The latter occurs when platelets have reached the end of their lifespan, which is 9–10 days in human, 4–5 days in mice. Like the other lineages of blood cells, the steady state level of platelets reflects the balance between their production and destruction. Any imbalance can result in bleeding or clotting tendencies, both of which may be life threatening.
We have found that a pro-survival member of the Bcl-2 protein family is essential for the maintainence of platelet survival in vivo. Mutations in the gene encoding this protein dramatically reduce platelet lifespan in a dose-dependent manner, resulting in thrombocytopenia. Strikingly, no effect on platelet production was observed, allowing us to distinguish the molecular control of platelet survival from that of platelet production. In a complementary approach, we employed a specific small molecule antagonist of the pro-survival Bcl-2-like protein. Treatment with this BH3 mimetic agent triggers features of apoptosis in platelets, dramatically reducing their survival both in vivo and in vitro. Platelet death can be prevented if they are pre-treated with a broad-spectrum caspase inhibitor or if platelets are derived from mice lacking an essential downstream mediator of apoptosis. Furthermore, the heritable thrombocytopenia in mice lacking the specific Bcl-2-like protein is corrected when this downstream target is genetically ablated. Thus, the balance between a Bcl-2-like pro-survival protein and its direct downstream pro-apoptotic target critically determines platelet survival, and hence circulating platelet numbers, in vivo.
These findings have notable implications for our understanding of platelet biology, strategies to promote platelet survival, and approaches to remove excess platelets that contribute to pro-thrombotic states.
IVIg-Primed Leukocytes Offer Longer Protection in the Amelioration of ITP Than IVIg.
Authors: Crow Andrew R. , Brinc Davor , Siragam Vinayakumar , Freedman John , Lazarus Alan H. 
Published: April 2020

Abstract
Using a murine model of ITP, we have previously demonstrated that both IVIg and a monoclonal antibody which reacts with red cells (TER-119), ameliorates thrombocytopenia. We have also recently demonstrated that passive transfer of IVIg-primed splenic leukocytes can completely recapitulate the effects of standard IVIg therapy in the amelioration of murine ITP, and further showed that CD11c+ dendritic cells were the primary cell mediating IVIg functions (Nat Med2006;12:688–692). However, the duration of action of IVIg, TER-119 and IVIg-primed leukocytes in the inhibition of murine ITP has not been evaluated. Herein, we have evaluated the efficacy and duration of action of IVIg-primed leukocytes compared with standard therapeutic delivery of IVIg and TER-119. On day 1, mice were pre-treated with 50 ug TER-119 or 50 mg IVIg, or with only 106 leukocytes that had been primed for 30 minutes with IVIg, followed by extensive washing to remove all extraneous IVIg. Alternatively, leukocytes were also primed as above with BSA as a negative control. On days 2, 5, 8 and 11, mice from each group were injected with an antibody directed to integrin αIIβ to induce immune thrombocytopenia and bled the following day for platelet enumeration. On days 3 and 6, platelet counts revealed that mice receiving IVIg-primed leukocytes, IVIg or TER-119 were all protected from thrombocytopenia to the same extent. Mice that were pre-treated with leukocytes primed with BSA were not protected, as expected. However, at day 9, mice that received IVIg-primed leukocytes were still completely protected from thrombocytopenia, while mice receiving IVIg or TER-119 were not protected. By day 12, none of the treatment regimens conferred protection from thrombocytopenia. We are currently repeating these experiments with IVIg-primed bone marrow-derived dendritic cells and these results will also be presented. These data confirm that in the treatment of murine immune thrombocytopenia, pre-treatment of mice with IVIg-primed leukocytes offers up to 50% longer duration of protection from thrombocytopenia than standard therapies with IVIg or TER-119.
A SERPINE1 (PAI-1) Single Nucleotide Polymorphism Predicts Osteonecrosis in Children Treated for Acute Lymphoblastic Leukemia: Results of the Children’s Oncology Group (COG) Study AALL03B2.
Authors: Hamilton Leo H. , Mattano Leonard A. , Sather Harland N. , Relling Mary V. 
Published: April 2020

Abstract
As intensity of glucocorticoid use has increased, osteonecrosis has become an increasingly frequent complication of modern intensive chemotherapy for pediatric patients with acute lymphoblastic leukemia (ALL). Although patient age &gt; 10 years is a well-known risk factor, other host risk factors that may predispose to this complication are not well described. We tested whether 12 polymorphisms in 11 candidate genes were associated with osteonecrosis among up to 344 patients ≥ 10 years old treated on the Children’s Cancer Group protocol CCG 1882 for newly diagnosed high-risk ALL, adjusting for gender, age, and treatment arm (augmented versus standard treatment). Genes tested (TYMS, ER, MTHFR, ABCB1, BGLAP (osteocalcin), ACP5, LRP5, ESR, SERPINE1, VDR, PTH, and PTHR) were chosen because they are candidates based on the putative mechanisms underlying osteonecrosis risk, including involvement in antifolate pharmacodynamics, drug pharmacokinetics, thrombosis risk, and possible hormonal influence on glucocorticoid effects. All children received dexamethasone during the delayed intensification phase of therapy, with doses varying by treatment arm (one dexamethasone pulse in the standard chemotherapy arm vs. two dexamethasone pulses in the augmented chemotherapy arm). Of the 11 candidate polymorphisms, a single nucleotide polymorphism (dbSNP rs6092) in the SERPINE1 gene (plasminogen activator inhibitor type 1 or PAI-1) was the only polymorphism associated with an increased risk of osteonecrosis in both univariate (p=0.0039) and multivariate (p=0.0019) analyses (adjusting for gender, age, and treatment arm), with an odds ratio of 2.51 (95% CI 1.32 to 4.74). Overall, 23.9% of the 88 children heterozygous or homozygous for the SERPINE1 T allele, versus 11.1% of the 234 children homozygous for the C allele, developed osteonecrosis. The combined CT or TT genotypes were present in a greater percentage (27%) of whites than in blacks (12%, p = 0.016), consistent with a higher risk (p = 0.003) of osteonecrosis in whites than blacks that was originally reported for CCG-1882 (J Clin Oncol18:3262–72, 2000). In a multivariate analysis, only the SERPINE1 polymorphism and sex predicted AVN, with the incidence of osteonecrosis lower in boys (odds ratio 0.49, 95% confidence interval 0.25 to 0.96, p = 0.034). No statistically significant gene-gene interactions between SERPINE1 and any other tested genotype were noted. SERPINE1 polymorphisms and PAI-1 serum levels have previously been associated with a clinical pro-thrombotic state. We conclude that polymorphisms in SERPINE1 may contribute to the risk of osteonecrosis in patients treated with glucocorticoids.
The Effect of Low Molecular Weight Heparin (LMWH) on Cancer Survival. A Systematic Review and Meta-Analysis (MA) of Randomized Trials.
Authors: Lazo-Langner Alejandro , Goss Glenwood D. , Spaans Johanna N. , Rodger Marc A. 
Published: April 2020

Abstract
Several studies have supported the existence of an antitumor effect of anticoagulants and several MA of studies comparing unfractionated heparin and LMWH for treatment of venous thromboembolism have suggested that the risk of mortality in the subgroup of cancer patients receiving LMWH might be reduced; however other authors have reported contrary findings. We conducted a systematic review and MA of randomized trials comparing LMWH with placebo/no intervention studying as the main outcome the impact on survival in cancer patients. Data sources were Medline, EMBASE, HEALTHstar, Cochrane Library, and grey literature. Data extraction was done by one reviewer and verified by a second reviewer. Discrepancies were resolved by consensus. Main outcomes were death at 1 year and major bleeding episodes. Secondary outcome was death at 2 years. A MA was done using a DerSimonian and Laird random-effects model with odds ratio (OR) and relative risk (RR) as summary statistics. We conducted a MA of survival rates using censored end-points and a MA of hazard ratios (HR). If not reported, HR were extracted from the survival curves and pooled using the generic inverse variance method (random effects model). 283 potential references were identified and 7 were fully evaluated. Four studies which enrolled 898 patients with solid malignancies (the majority with extensive disease) were included; 3 of the 4 studies included previously treated patients. OR and RR of death are shown in the table.
Mortality in cancer patients receiving LMWH versus placebo/no treatment All Patients Patients with advanced disease OR 95% CI P OR 95% CI P OR odds ratio; CI confidence interval; RR relative risk 1-year mortality 0.70 0.49, 1.00 0.05 0.75 0.57, 0.99 0.04 2-year mortality 0.57 0.34, 0.96 0.03 0.59 0.42, 0.84 0.004 RR 95% CI P RR 95% CI P 1-year mortality 0.87 0.77, 0.99 0.04 0.89 0.80, 0.99 0.03 2-year mortality 0.90 0.84, 0.97 0.007 0.92 0.86, 0.98 0.02
The results of the survival meta-analysis showed that the pooled survival proportions at 1 and 2 years were 0.43 and 0.19 for the LMWH and 0.35 and 0.11 for the control group, respectively; differences were statistically significant (1 year p=0.018, 2 year p=0.001). The MA of HR is shown in the figure.
Figure Figure
There was no increase in major bleeding episodes. Sensitivity analyses including only patients with advanced disease did not modify the findings; an analysis according to tumor type was not conducted due to a lack of information. LMWH improves overall survival in cancer patients independent of the stage. Additional trials are required to define the tumor types, disease stages, and dosing schedules most likely to derive the greatest survival benefit. Since the majority of patients included were previously treated, exploring the benefit of LMWH in newly diagnosed patients is necessary.
Immunomagnetic Depletion of CD25-Expressing T Cells from Donor Blood Removes a Mixed Population of Regulatory and Effector T Cells - Implications for Graft Engineering.
Authors: Melenhorst J. Joseph , Lu Jun , Sosa Edgardo , Hensel Nancy F. , Barrett A. John 
Published: April 2020

Abstract
CD4+CD25+FOXP3+ regulatory T cells (TR) control proliferative CD4 and CD8 T cell responses to self and foreign antigens such as cytomegalovirus (CMV) and tumor-specific antigens. Thus, depletion of CD25-expressing cells from a resting population of T cells prior to antigen stimulation could boost the generation of antigen-specific T cells for adoptive transfer to treat viral infection or tumors. We depleted peripheral blood mononuclear cells (PBMC) from nine CMV seropositive donors using Miltenyi CD25 microbeads (20 μl/107 cells). CD25-depleted or unmanipulated PBMC were stimulated with CMV pp65-expressing antigen presenting cells for 10–14 days with low dose IL-2, and intracellular interferon-gamma (IFNγ) production by flow cytometry was compared between CD25-depleted and -undepleted cultures. An absolute increase in antigen-specific CD4+ and CD8+ T cells was seen after CD25 depletion in 4/8 and 5/8 cultures respectively. However, in other cultures there was a decrease or no change in IFNγ+ CD4+ T cells in CD25-depleted cultures, suggesting that the pp65-specific precursor cells had also been removed. We then used 4 μl beads per 107 PBMC to selectively remove only the CD25bright (predominantly Treg) population in nine donors and confirmed by flow cytometry that only CD25bright cells had been removed from the starting population. However, real-time quantitative PCR (Q-PCR) showed that even though the CD25+ fraction was enriched in FOXP3-expressing cells, a substantial proportion of the CD25-depleted PBMC still expressed FOXP3. Flow cytometric analysis of FOXP3 expression by CD25+ and CD25-negative CD4+ T cells showed that a substantial proportion of CD25- cells expressed FOXP3, confirming that CD25 is not a suitable single marker for depletion of Tregs. Again no reproducible augmentation of antigen-specific T cell responses was observed: one and five donors showing an increase in CD4 and CD8+ antigen-specific T cells, respectively, while the remainder showed a decrease or no change in CD4+ and CD8+ IFNγ-producing cells. These results suggest that removal of CD25+ cells from PBMC using CD25 microbeads removes both Treg and pp65-specific effector CD4+ and CD8+ T cells. Further, since FOXP3 is induced in responder cells as confirmed by FOXP3 Q-PCR, depletion of Treg at the start of the cultures may only transiently alleviate the negative regulation of the antigen response. Thus, CD25 depletion using microbeads is not a reliable method to boost antigen specific T cell expansions because of the inadvertent removal of a portion of the memory response to the antigen. Since it recently has been demonstrated that Treg act as an IL-2 sink, the addition of this cytokine should functionally silence the Tregs while preserving the inflammatory response.
Modulating AML1-ETO with Signature-Based Small Molecule Library Screening.
Authors: Stegmaier Kimberly , Corsello Steven M. , Ross Kenneth N. , Golub Todd R. 
Published: April 2020

Abstract
We sought to develop a strategy to pharmacologically modulate AML1-ETO, the most common gene rearrangement associated with acute myeloblastic leukemia (AML). Like many other oncogenic transcription factors associated with the acute leukemias, AML1-ETO has been considered undruggable. In principle, these well-characterized somatic mutations identified in the acute leukemias represent unique, tumor-specific therapeutic targets. In practice, acute leukemia therapy continues to focus on nonspecific cytotoxic agents. In order to address this challenge, we developed a genomic, signature-based small molecule library screening approach, Gene Expression-based High-throughput Screening (GE-HTS). This approach uses gene expression signatures as surrogates for different biological states in a small molecule library screen. We focused our initial efforts on identifying modulators of AML1-ETO. First, a 25-gene signature for AML1-ETO abrogation was defined by transcriptional profiling of t(8;21) Kasumi-1 cells with and without AML1-ETO-directed RNA interference and with a U937 inducible model of AML1-ETO. The signature was confirmed in microarray data from t(8;21)-containing primary patient leukemias (p &lt; 0.001). Next, the ability of 2,600 FDA-approved drugs and bioactive agents to induce this abrogation signature was evaluated by ligation mediated amplification (LMA) and bead-based fluorescence detection. The screen identified 16 hits confirmed on repeat testing, including seven corticosteroids. Five hits were selected for further study based on their chemical diversity, ability to induce a robust expression signature, and potential for clinical translation: 5-aza-deoxycytidine, floxuridine, methotrexate, methylprednisolone, and pyrimethamine. Next, whole genome effects of these compounds with microarray-based expression profiling were evaluated. Using Gene Set Enrichment Analysis (GSEA), we determined that all five compounds induce both whole genome effects consistent with AML1-ETO knockdown and a whole genome program consistent with neutrophil maturation. In a subset of these compounds, we also see changes in cell surface markers and morphological features consistent with myeloid maturation. Intriguingly, two of the hits are well-characterized DNA methyltransferase inhibitors, and two of the hits are dihydrofolate reductase inhibitors that increase S-adenosylhomocysteine, an inhibitor of methyltransferases. Thus, reversal of AML1-ETO-mediated gene silencing by demethylation may overcome its repressive effects. This application of knockdown-derived expression signatures to small molecule library screening should enable the targeting of nearly any oncogenic transcription factor.