bluuebunny/crossref_metadata_2025_split huggingface dataset:
Bone Marrow Endothelial Cell Support of Primitive Hematopoietic Cells
Authors: Zhou Xiaoying , Rosa Dilani , Cunningham Cynthia , Adams Gregor B. 
Published: October 2019

Abstract
Hematopoietic stem cells (HSCs) in the bone marrow (BM) reside in specialized microenvironments known as the stem cell niche. Many reports have found the HSCs to be resident next to the endosteal surface of bone where cells of the osteoblastic lineage are a key component of the so-called endosteal niche. However, HSCs have also been found to reside adjacent to sinusoidal blood vessels. These observations have led to the proposal that HSCs in the adult BM may also reside in a vascular niche. However, the functional role of the vascular niche in hematopoiesis remains to be determined. We wished to evaluate the role that BM endothelial cells (BMECs) play in HSC physiology. To examine this we cultured BMEC-enriched cells in vitro, identified by expression of CD31, Tie-2, VE-cadherin and LDL uptake. We compared these cells to spleen derived ECs and BM stromal cells (BMSCs) in their ability to support primitive hematopoietic cells for extended periods in in vitro culture. We found that BMECs were superior in their ability to support the cobblestone area forming cell activity of VEGF-R1+ HSCs than spleen ECs or BMSCs. We also found that the number of cobblestone area cells was markedly reduced when VEGF-R1− HSCs were cultured on any of the supportive cell layers, however this may be due to an intrinsic difference between these cells as a much higher proportion of VEGF-R1+ HSCs were found to be in the G0 phase of the cell cycle than VEGF-R1− cells. To evaluate the supportive role of BMECs, spleen ECs or BMSCs on hematopoietic progenitor cells (HPC) we cultured purified primitive cells on these supportive layers and the total number of colony-forming unit-culture (CFU-C) cells were examined after 4-days or 7-days co-culture with the feeder cells. The results showed that BMECs or spleen ECs can promote the generation of CFU-C from VEGFR1+ HSCs or VEGFR1− HSCs, yet the tot al number of CFU-C produced from VEGFR1+ HSCs was greater than that from VEGFR1- HSCs. However, both of these cell types were able to support the generation of CFU-Cs to a greater degree than BMSCs. To examine the mechanism of enhanced support of VEGF-R1+ HSCs by the BMECs, we performed real-time PCR analysis for the expression of the VEGF-R1 ligands. Both BMECs and spleen ECs were found to express VEGF-A and –B to similar levels, however the expression of placental growth factor was higher in the BMECs. Whether the increased expression of this factor plays a functional role in the support of the HSCs in currently being evaluated. Our findings suggest that the ECs from BM or spleen can promote the proliferation of hematopoietic progenitor cells, while BMECs can maintain the long-term culture of VEGFR1+ HSCs in vitro. The functional relevance of this in vivo is currently being investigated.
Ajuba Functions as An HDAC-Dependent Co-Repressor for Autoregulation of the Growth Factor Independent-1 Transcription Factor
Authors: Rojas Meghan E. B. , Velu Chinavenmeni S. , Montoya-Durango Diego E. , Kazanjian Avedis , Jay Chris M. , Longmore Gregory D. , Grimes H. Leighton 
Published: October 2019

Abstract
Growth factor independent-1 (Gfi1) is mutated in patients with Severe Congenital Neutropenia. Gfi1 is a zinc finger protein with a SNAG-transcriptional repressor domain. The SCN-associated Gfi1 mutant proteins function as dominant negatives to sequester limiting SNAG-dependent corepressor proteins from the remaining wild type Gfi1 protein, and deregulate a subset of Gfi1 target genes such as CSF1. The identity of the critical Gfi1 SNAG-domain-associated co-repressor proteins is unknown. Ajuba is a LIM-domain protein that shuttles between the cytoplasm and the nucleus. Ajuba functions as a co-repressor for synthetic Gfi1 SNAG-repressor-domain containing constructs, but a role for Ajuba co-repression of the cognate DNA bound Gfi1 protein has not been defined. Coimmunoprecipitation of synthetic and endogenous proteins, and co-elution with gel filtration identified an endogenous Ajuba-Gfi1-HDAC multiprotein complex. Active histone deacetylase activity co-immunoprecipitates with Ajuba or Gfi1, and both proteins depend upon histone deacetylases for full transcriptional repression activity. Ajuba LIM domains directly bind to Gfi1, but the association is not SNAG domain dependent. ChIP analysis and reciprocal knock-down experiments suggest that Ajuba selectively functions as a co-repressor for Gfi1 autoregulation. The data suggest that Ajuba is utilized as a corepressor selectively on a subset of Gfi1 target genes, but is not the critical SNAG-dependent cofactor sequestered by SCN-associated Gfi1 mutant proteins.
Treatment of High Grade B-Cell Lymphoma with Chemotherapy Plus Rituximab: A Survival Benefit Can Be Demonstrated in the Routine Data of a Regional Cancer Registry
Authors: Krause Stefan W , Andreesen Reinhard , Hofstädter Ferdinand , Gerken Michael 
Published: October 2019

Abstract
Introduction: Combination of standard chemotherapy with Rituximab led to improved disease control in pts. with B-cell lymphoma and a clearcut survival benefit in diffuse large B cell lymphoma (DLBCL) in a multitude of clinical trials. We wanted to know, if a similar benefit could be demonstrated in the routine follow-up data of the regional population-based cancer registry of the Regensburg cancer center (“Tumorzentrum Regensburg”, TUZ). The TUZ spreads evidence-based treatment recommendations, but beyond this, treatments are performed according to the discretion of individual physicians and institutions.
Methods: We searched the registry for B-NHL diagnosed between 1998 and 2005 entered as DLBCL, mantle cell lymphoma (MCL), follicular lymphoma (FL), undefined low grade lymphoma and corresponding terms from the ICD-O3. Furthermore, death certificates were systematically matched to the patient data and additionally searched for the terms C82, 83, 85, 88 of the ICD-10. Using these data, we compared overall survival of patients receiving any first line chemotherapy plus rituximab and patients receiving chemotherapy alone.
Results: Comparing registry data to death certificates an 85% coverage of lymphoma patients within the registry can be estimated. In the high grade lymphoma group, 450 patients have been entered into the registry. Of these, 49 were insufficiently documented, 29 patients had a delayed start of their treatment and 41 received no chemotherapy at all. 122 pts. received rituximab-containing chemotherapy resulting in a 2 year survival of 87%, whereas 209 pts. received chemotherapy alone with a significantly inferior 2 year survival of 70%, p=0,004 by log rank test (fig). 307 pts with low grade lymphoma were found. Of these, 31 were insufficiently documented. 84 pts. did not receive any therapy at all during the observation period and showed the best survival as expected (watch and wait). 69 and 123 pts. received first line chemotherapy with or without Rituximab, respectively. Regarding all low grade NHL together, no significant difference was found, however, FL pts. survived longer, when Rituximab was given (2 year survival 91% vs. 72%, p=0,046).
Conclusions: A survival benefit comparable to the results within clinical trials can be observed in registry data in an unsupervised community setting for patients with DLBCL treated first line with a Rituximab containing chemotherapy. A strong trend for improved survival was also observed for FL. These data confirm the standard use of Rituximab as first line therapy in DLBCL and FL and they support the collection of an extended set of treatment data containing exact descriptions of systemic therapy in cancer registries in order to answer similar questions in the future.
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High-Dose Methotrexate and Cytarabine Chemotherapy May Be Effective and Safe in Solid Organ Transplant Recipients with Primary CNS Lymphomas (PCNSL)
Authors: Moise Laura , Matta Clemence , Pilorge Sylvain , Moldovan Marius , Ferme Christophe , Durrbach Antoine , Ribrag Vincent 
Published: October 2019

Abstract
Background: Post transplant lymphoproliferative disorder (PTLD), especially primary CNS lymphoma (PCNSL), is a serious complication of solid organ transplantation. Treatment has proved difficult and includes dose reduction of immune suppression (RIS), combination chemotherapy and radiotherapy. Recently the monoclonal antibody Rituximab, has been added to the therapeutic choice. Chemotherapy used in PCNSL is based on high-dose methotrexate (HDMTX), but need to be carefully monitored in adult patients (pts), especially with renal transplant. HDMTX could be associated with deleterious effects on renal graft function. We report here the results of HDMTX in pts with PCNSL after solid organ transplantation treated at the Institut de Cancérologie Gustave Roussy.
Methods: From February 2000, 18 pts with PTLD were referred to our Institute. 9 of them had PCNSL following renal (6), hepatic (1) or both renal and pancreatic (2) transplants. In all cases, RIS was not associated with PCNSL regression. Except in one case, all pts were treated with chemotherapy with HDMTX in 3-hour infusion. Folinic acid rescue was given IV every 6 hours (50 mg/m2) combined with alkaline hyper-hydration until MTX serum level was below 1 X 10–7 M. Immune suppressive therapy (IST) was reduced to solupred (10 mg/day) during chemotherapy and was reduced for 8 months after chemotherapy. 4 cycles of chemotherapy was planned and efficacy assessed every two cycles. If CR was reached with chemotherapy alone, no radiotherapy was delivered.
Results: From March 2007, 9 pts (4 males) developed PCNSL with a median of 6 years after transplant (1–26 years). Median age was 55 (range 33–70). PS was > 2 in 8/9 and 3 in one case. 8/9 pts had glomerular filtration rate > 60 ml/mn and received HDMTX without renal toxicity. One pt with GFR < 60 ml/mn was treated with 3 cycles of HD cytarabine + rituximab and adryamicin and is alive in complete remission (CR) 31 months after therapy. With a median follow up of 15 months, 4/9 pts are alive and in CR 45, 31, 29 and 7 months after therapy. 3 of them received radiotherapy. 5 pts died, 2 of lymphoma progression, 2 of chemotherapy toxicity (sepsis) and one of a gastric cancer. No graft rejection was observed.
Conclusions: our results suggest HDMTX can be given in pts with PCNSL and long term CR can be reached without graft failure. As chemotherapy regimens used for in those pts are in themselves immunosuppressive, IST may be reduced during chemotherapy without major risk.
Depletion of the C3 Component of Complement Enhances the Ability of Rituximab-Coated Target Cells to Activate Human NK Cells and Improves the Efficacy of Monoclonal Antibody Therapy in An in Vivo Model
Authors: Wang Siao- Yi , Cagley Jeffrey , Fritzinger David , Vogel Carl-Wilhelm , John William St. , Weiner George J 
Published: October 2019

Abstract
Antibody-dependent cellular cytotoxicity (ADCC) is felt to play an important role in mediating the anti-tumor effects of Rituximab (R). We previously reported that C3b deposition on R-coated target cells interferes with the binding of the Fc portion of R to NK cell CD16. This interaction inhibits the activation of NK cells and NK cell-mediated ADCC of 51Cr-labeled R-coated target cells. The current studies were designed to determine whether C3 depletion enhances the ability of mAb-coated targets to activate NK cells in vitro and improves mAb therapy in vivo. Normal human serum inhibited the ability of R-coated lymphoma cells to activate NK cells as previously reported. NK activation was increased when serum was pre-incubated with cobra venom factor (CVF) to deplete C3. Similar results were found when non-malignant ascites or transudative pleural fluid, as a surrogate for extravascular fluid, was used as the source of complement. For in vivo analysis, we utilized a syngeneic, immunocompetent murine model in which ADCC has been previously demonstrated to be a key mechanism of action. CVF or a human C3 derivative with CVF-like functions (HC3-1496) was used to deplete C3 in vivo. In this model, C3H/HeN mice were inoculated with murine 38C13 lymphoma cells (day 0) and treated with 2 doses of CVF or HC3-1496 (day 3 and day 5). Four hours after the initial dose of CVF or HC3-1496, mice were treated with a single dose of an anti-lymphoma mAb directed against the 38C13 idiotype (MS11G6). Untreated mice all developed tumor and died with a median survival of 28 days. All mice treated with mAb alone eventually developed tumor and died with a median survival of 42 days. Survival following treatment with CVF plus mAb was superior to that of mAb alone (Fig 1, p=0.0312) with 50% of mice remaining tumor free. Survival following treatment with HC3-1496 plus mAb was also superior to that of mAb alone (Fig 2, p=0.0002) with 80% of mice remaining tumor free. In summary, depletion of the C3 component of complement enhanced the ability of R-coated target cells to activate human NK cells, and improved the efficacy of mAb therapy in an in vivo model of lymphoma. Furthermore, these studies suggest the inhibitory effects of complement on NK activation and ADCC may be seen in the extravascular compartment such as within involved lymph nodes. We conclude that depletion of complement through use of agents such as CVF or HC3-1496 could be considered as an approach to enhancing the efficacy of R therapy.
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Increased Reactive Oxygen Species Induced by NUP98-HOXD13 Fusion Gene in MDS Mouse Model
Authors: Chung Yang Jo , Aplan Peter D. 
Published: October 2019

Abstract
The myelodysplastic syndromes (MDSs) comprise a group of pre-malignant hematologic disorders characterized by ineffective hematopoiesis, dysplasia, and transformation to acute myeloid leukemia (AML). The causative agents for de novo or therapy-related MDS (t-MDS) include exposure to known genotoxins, such as benzene and other solvents, anti-cancer chemotherapy, and ionizing radiation. It is known that MDS is closely related to chromosomal aberrations including deletions, amplifications, inversions, and translocations, however, the molecular mechanism of disease progression from MDS to AML not been completely elucidated. Recently, several studies have reported that oxidative stress contributes to the disease progression mechanism in MDS. Reactive oxygen species (ROS) play a role in regulating several biologic phenomena involving activation of signaling pathways in response to cytokines, and the gene expression induced by this signaling. ROS is also known to induce oxidative DNA damage which generates DNA base modifications and DNA helix alterations. Therefore, increased intracellular levels of ROS can induce mutations which lead to transformation of MDS to AML. A mouse model for MDS, generated by expressing a NUP98-HOXD13 (NHD13) fusion gene was exploited to investigate ROS levels in this study. Lineage negative (Linneg) bone marrow mononuclear cell (BMNC) from NHD13 mice with MDS had a 7.8±5.6 fold increased level of ROS compared with wild-type (WT) Linneg BMNC, while ROS levels of unfractionated BMNC were similar in NHD13 and WT mice. The increase ROS level in NHD13 Linneg BMNC was associated with an increase in G2/M phase (2 fold). Interleukin 3 (IL-3) dependent NHD13 ‘knock-in’ cell lines also showed an increased level of ROS (3 to 5 fold), in comparison with other IL-3 dependent cell lines, BaF3 and 32D. To determine if the increase in ROS could be generated by an NHD13 fusion, BaF3 and 32D cell were transfected with an NHD13 expression vector. The BaF3 and 32D transfectant showed 2 fold (2.1±0.3 and 1.9±0.6 fold) increase ROS level compared to controls transfected with an empty vector. These findings suggest that expression of an NHD13 fusion gene can induce ROS in hematopoietic progenitor cells, which may contribute to the development of MDS and subsequent disease progression to AML through DNA damages.
Induction of Sustained Early G1 Arrest by Selective Inhibition of CDK4 and CDK6 Primes Myeloma Cells for Synergistic Killing by Proteasome Inhibitors Carfilzomib and PR-047
Authors: Huang Xiangao , Bailey Kathryn , Di Liberto Maurizio , Parlati Francesco , Niesvizky Ruben , Demo Susan , Chen-Kiang Selina 
Published: October 2019

Abstract
Targeting the cell cycle in combination with cytotoxic killing is a rational approach to cancer therapy. Dysregulation of the cyclin-dependent kinases CDK4 and CDK6 precedes uncontrolled proliferation of myeloma cells in vivo, in particular during relapse and drug resistance. This finding reinforces the critical importance of targeting CDK4/6 in myeloma, but success with broad-spectrum CDK inhibitors has been modest. Using the only known selective inhibitor of CDK4/6, PD 0332991, we have developed a novel approach to prime chemoresistant myeloma cells for synergistic killing by diverse cytotoxic agents. We show that selective inhibition of CDK4/6 by PD 0332991 leads to sustained cell cycle arrest in early G1 in the absence of apoptosis. However, it markedly augments cytotoxic killing by PR-171 (carfilzomib), a selective inhibitor of the chymotrypsin-like activity of the proteasome, or PR-047, an orally bioavailable analog of carfilzomib. Synergistic killing of myeloma cells arrested in early G1 by carfilzomib (or PR-047) is caspase-dependent, and requires only a brief (one hour) exposure to the proteasome inhibitor at concentrations as low as 60 nM. This effect is mediated by synergistic and rapid induction of mitochondrial membrane depolarization and activation of downstream caspase-9 within 6 hours of removal of carfilzomib or PR-047. As PD 0332991 acts as an ATP-competitive inhibitor of the CDK4/6 kinase domain, inhibition of CDK4/6 and the cell cycle by PD 0332991 is reversible. Importantly, targeting CDK4/6 with PD 0332991 in combination with either carfilzomib or PR-047 leads to complete eradication of myeloma cells ex vivo, in contrast to the combination of PD 0332991 with other proteasome inhibitors. Selective inhibition of CDK4/6 in combination with carfilzomib (or PR-047), therefore, not only halts cell proliferation but also potently induces synergistic killing that is likely to eliminate cell cycle reentry and generation of resistant cells. PD 0332991 is a small molecule with bio-availability and proven tumor suppressing activity in both human myeloma xenograft and immunocompetent mouse myeloma models. It is well tolerated in humans as shown by the ongoing Phase I/II clinical trials in myeloma and previous phase I trials in mantle cell lymphoma and solid tumors. Evidence from Phase I trials of carfilzomib indicates that it is also well tolerated, in fact, the peripheral neuropathy that is commonly observed with proteasome inhibitor bortezomib appears to be less severe and possibly less frequent. Mechanism-based targeting of CDK4/6 in combination with selective proteasome inhibitors, like carfizomib and PR-047, thus represents a new and promising therapeutic strategy for multiple myeloma and potentially other hematopoietic malignancies.
Structure of the Notch1 Negative Regulatory Region: Implications for Normal Activation and Pathogenic Signaling in T-ALL
Authors: Gordon Wendy Ryan , Roy Mondeepa , Vardar-Ulu Didem , Garfinkel Megan , Mansour Marc R , Aster Jon C , Blacklow Stephen C 
Published: October 2019

Abstract
Proteolytic resistance of Notch prior to ligand binding depends on the structural integrity of a negative regulatory region (NRR) of the receptor that immediately precedes the transmembrane segment. The NRR includes the three Lin12/Notch repeats and the juxtamembrane heterodimerization domain, the region of Notch1 most frequently mutated in T cell acute lymphocytic leukemia. Here, we report the X-ray structure of the Notch1 NRR determined to 2.0 Å resolution in its autoinhibited conformation. A key feature of the Notch1 structure that maintains its closed conformation is a conserved hydrophobic plug that sterically occludes the metalloprotease cleavage site. Crystal packing interactions involving a highly conserved, exposed face on the third Lin12/Notch repeat suggest that this site may normally be engaged in inter- or intra-molecular protein-protein interactions. The vast majority of known T-ALL-associated point mutations of human Notch1 map to residues in the hydrophobic interior of the NRR. A novel mutation (H1545P), which alters a residue at the crystal-packing interface, leads to ligand-independent increases in signaling in reporter gene assays despite only mild destabilization of the NRR, suggesting that it releases the autoinhibitory clamp on the heterodimerization domain imposed by the Lin12/Notch repeats. The Notch1 NRR structure should facilitate a search for antibodies or compounds that stabilize the autoinhibited conformation.
EVI1 Blocks Apoptosis in DA-1 Myeloid Leukemia Cells Via Enhanced Transcription of the Prosurvival Gene Bcl2a1 (A1)
Authors: Perkins Archibald S. , del Campo Jacob J. , Xiao Ying-Yi , Zhang Yi , Lin Sharon J. , Dudley Jonathan , Tuck David , Yatsula Bogdan 
Published: October 2019

Abstract
Retroviral insertion at the Evi1 locus causes high level of expression of the gene in myeloid neoplasms in mice and in nonmalignant expansions of myeloid cells in humans and monkeys. In these settings, it is suggested that EVI1 confers a survival advantage on myeloid cells. Here, we investigate the survival phenotype in DA-1 cells, a leukemic cell line with provirally activated Evi1. We report that short hairpin-mediated suppression of Evi1 in DA-1 cells induces apoptosis via the intrinsic/mitochondrial pathway: DNA fragmentation and histone release are both induced, as is reduction in mitochondrial membrane potential. In addition, procasapses 3 and 9, but not caspase 8 or Bid, are cleaved following Evi1 knockdown; phosphoAKT remains unchanged. Furthermore, mRNA expression profiling following Evi1 suppression show transcriptional changes in several apoptotic regulators, including a 3.5-fold decrease in Bcl2a1 (bfl/A1), a prosurvival member of the Bcl-2 family. To assess whether EVI1 regulates Bcl2a1 expression in a cell type other than DA-1 cells, we transduced primary murine Lin-/Sca-1+/c-Kit+ cells with EVI1 via retroviral vector, and then assessed the expression of Bcl2a1. This revealed that EVI1 induced a more than five-fold increase in Bcl2a1 mRNA expression, as measured by quantitative PCR. Furthermore, transduction of primary murine bone marrow cells with retroviruses bearing either Bcl2a1 or Evi1 resulted in a significant decrease in spontaneous apoptosis, as assessed by the activity of caspases 3 and 7. To further test if Bcl2a1 is necessary for leukemic transformation by Evi1, we assessed the ability of Evi1 to confer serial replating ability on primary bone marrow cells from Bcl2a1−/− mice. Bone marrow was harvested from Bcl2a1−/− and C57BL6 mice and transduced with retrovirus containing either no gene or Evi1. While in C57BL6 mice, Evi1 induced a significant increase in colonies, bone marrow from Bcl2a1−/− mice were resistant to transformation by Evi1. To show that this was due to the lack of Bcl2a1, the gene was added back via retrovirus. While Bcl2a1 by itself did not induce significant number of colonies over vector, when introduced into Bcl2a1−/− cells together with Evi1, there was a significant increase in colony formation. These data indicate that transformation of bone marrow cells by Evi1 depends on the presence of the Bcl2a1 gene. We further show EVI1 can transcriptionally upregulate a BCL2A1::luc reporter that harbors 1.37 kb of the human BCL2A1 upstream sequence. Our analysis of the Bcl2a1 promoter indicates that the effect of EVI1 is likely indirect. Based on our findings, we propose that EVI1 acts to block apoptosis in DA-1 cells by transcriptionally activating Bcl2a1.