julilili42/papers huggingface dataset:
Outcome of Allogeneic Hematopoietic Cell Transplantation in AML or MDS with a HLA-Mismatched Unrelated Donor: A Single Center Analysis
2014-12-06

Abstract Introduction: In acute myeloid leukemia (AML) and myelodysplastic syndrome (MDS), allogeneic hematopoietic cell transplantation (HCT) can constitute a curative treatment option. Best results are reported using 10/10 HLA-matched donors, and several reports indicated inferior outcomes because of increased graft versus host disease (GVHD) and non-relapse mortality (NRM) if a HLA-mismatched donor is used. Methods: Here we present a single center analyses evaluating all patients (pts) with AML or MDS receiving allogeneic HCT with a mismatch unrelated donors (MMUD) between 2004 and 2014. Results:137 pts were evaluated. Median age was 51 years (range 18-76). For myeloablative conditioning (n=52) the following regimens were used: 12 Gy total body irradiation (TBI) and high-dose cyclophosphamide (n=40), or high-dose busulfan and cyclophosphamide (n=8); for reduced intensity conditioning (n=83) fludarabine with either busulfan (n=27), melphalan (n=6), treosulfan (n=7), cyclophosphamide (=15) or TBI (n=19) was used. Stem cell sources were either peripheral blood (n=134) or bone marrow (n=3). The donor/recipient match was a 9/10 alleleic mismatch in 41% and a 9/10 antigen-mismatch in 59% of cases. All but 21 patients received antithymocyte globuline prior to transplantation for GVHD prophylaxis. Post-transplant immunosuppression consisted of a combination of calcineurine inhibitors with either methotrexate (n=65) or mycophenolate mofetil (n=28). Kaplan-Meier estimated overall survival (OS) for all patients at 1 year was 70% and at 3 years 23%. Cumulative incidence of relapse was 32%. Median follow up of patients alive was 40 months (4-122 month). Engraftment with &gt;500 neutrophils and &gt;25.000 platelets was observed at a median of 20 and 20 days after HCT, respectively. Cumulative incidence of NRM until day 100, 1 year and 3 years was 16%, 27% and 28%, respectively. OS and NRM were not different in pts with allelic or antigen-mismatched donors (OS at 1 year/3 years: 65%/48% versus 48%/33% (p=0,2411), NRM at day 100, 1 year and 3 years: 21%, 24% and 33% versus 20%, 27% and 37% (p=0,6210) ). Acute GvHD mostly occurred at lower grades (grade I 34%, grade II 16%, ≥ grade III 10%). Risk of acute GVHD for patients with an antigen-mismatched donor was not different compared to those with an allelic-mismatched donors (51% versus 42%, p=0,4086). Conclusion: Stem cell treatment with mismatched donors in allogeneic HCT is a valuable and safe option for pts with missing matched stem cell source. Due to optimized pre- and-posttransplant treatment, satisfactory long term survival can be achieved. Disclosures No relevant conflicts of interest to declare.
An Fc-Engineered CD133 Antibody for Induction of NK Cell Reactivity Against Cancer Cells
2014-12-06

Abstract CD133 is expressed in various types of solid tumors where it predicts an unfavourable clinical outcome (e.g. Linuma et al., J Clin Oncol. 2011). Moreover, CD133 has been shown to be preferentially expressed by cancer stem cells (CSC), as e.g. demonstrated by its usability to enrich CSCs containing populations within cancer cell preparations (e.g. Zeppernick et al., Nature 2008). As CSC display marked resistance to chemo- and radiation therapy, great efforts are presently made to develop immunotherapeutic approaches to specifically target CSC without harming healthy tissue. We here report on the preclinical characterization of a monoclonal antibody (mAb) directed towards CD133 for induction of NK cell reactivity against cancer cells. Two different anti-CD133 antibody clones (W6B3 and 293C3) were used to study expression levels of CD133 in different cell lines derived from solid tumors (A172 and U87MG, glioblastoma; CaCo-2, Colo-205, HCT-8, HT-29 and SW48, colorectal cancer; MDA-MB-231, MDA-MB-468 and BT474, breast cancer; WERI-Rb1, retinoblastoma). CD133 was recognized by W6B3 and 293C3 in 4 and 5 out of the 11 cell lines, respectively. The latter mAb was then chosen for the development of chimeric mAbs with either a wildtype human Fc part (293C3-WT) or a variant containing amino acid exchanges (S239D/I332E) to enhance its affinity to the activating Fc receptor CD16 (293C3-SDIE) and thereby its capacity to mediate antibody dependent cellular cytotoxicity (ADCC), an important antibody property that largely contributes to the clinical success of antitumor mAbs. After confirming the binding specificity of both 293C3-WT and 293C3-SDIE we employed cytotoxicity assays to comparatively analyze their ability to induce NK cell ADCC against different solid tumor cell lines. In all cases, profound induction of tumor cell lysis upon application of 293C3-SDIE was observed, and the therapeutic effect of the Fc-optimized mAb clearly exceeded that of its counterpart containing a wild type Fc part. Notably, colony forming unit assays did not reveal any toxicity of 293C3-SDIE at the level of committed hematopoietic progenitor cells. Thus, treatment with 293C3-SDIE constitutes a promising novel strategy for immunotherapy of cancer, in particular considering its ability to preferentially target CSC which is presently under study. Disclosures No relevant conflicts of interest to declare.
High Dose-Chemotherapy Followed By Autologous Peripheral Blood Stem Cell Transplantation for Patients with Refractory or Recurrent Primary Central Nervous System Lymphoma –Results of a Multicenter Study By the Germany Collaborative PCNSL Study Group
2014-12-06

Abstract Introduction: Primary central nervous system lymphoma (PCNSL) relapses in up to 60% after conventional chemotherapy. The prognosis of refractory or recurrent PCNSL is very poor with a median survival of up to 5 months. Whole brain radiotherapy may improve survival up to 10 months, but is associated with significant neurotoxicity. High-dose chemotherapy (HDT) and autologous stem-cell transplantation (ASCT) have demonstrated high efficacy in the treatment of newly-diagnosed primary CNS lymphoma (PCNSL) in younger patients (pts.). To evaluate the efficacy of this approach, we initiated a prospective multicenter phase II study with HDT and ASCT for relapsed PCNSL. This trial is registered at ClinicalTrials.gov (NCT 00647049) Patients and Methods: Thirty eight pts. &lt;65 years were treated within the phase II trial, chemotherapy (CHT) consisted of 2 cycles of Rituximab (3,75mg/m2), AraC (2x 3 g/m2) plus thiotepa (TT, 40 mg/m2) followed by rG-CSF and stem-cell-mobilization after the 1st cycle. Conditioning regimen included BCNU (400 mg/m2) and TT (4x5 mg/kgBW) followed by ASCT. Patients not in complete remission after HDT and ASCT underwent WBRT. Results: From 2007 to 2012, 38 pts (18 female, 20 male) with relapsed (n=31) or refractory (n=7) PCNSL from 10 German centers were enrolled and evaluable for analysis (median age 58 years, range 37-66 years). All pts had aggressive B-cell lymphomas (DLBCL). Median Karnofsky performance status at diagnosis was 90% (range 60-100). Patients were intensively pretreated, all pts underwent HD-MTX within the first-line-treatment, 15 of 38 pts were treated within the Bonn protocol. Thirty-one of 38 pts (81,6%) received HDT and ASCT according to protocol. Three pts died before PBSCT, 4 further pts were treated off study due to PD (n=2), refusal of HDT (n=1) and insufficient stem cell harvest (n=1). Regarding the primary endpoint in the intent-to-treat population, 22 pts (57,9%) achieved complete (CR) and and 5 (13,2%) partial remission (PR) after HDT and ASCT, respectively. In patients treated per protocol, the CR and PR-rate rate was 71% and 16,1% respecticely. The overall respinse rate in the per protocol population was 86,1%. Six pts in PR after HDT and ASCT received consolidating WBRT. After a median 39-month follow-up (range 0-48 mo), 1 and 2 years OS was 63% and 57%, respectively. Median survival of the intent-to-treat population was 29 months. Further results will be presented. Conclusion: Sequential systemic application of high-dose cytostatic agents followed by HDT+ASCT is highly effective as salvage therapy for pts. with relapsed or refractory PCNSL. Disclosures Illerhaus: Riemser: Honoraria. Wolf:Bayer: Honoraria; Geo Pharma: Honoraria. Stilgenbauer:Pharmacyclics, Janssen: Honoraria, Research Funding.
ASPP2 Attenuation Is an Early Step in Leukemogenesis Facilitating Acquisition of Mutations
2014-12-06

Abstract Inactivation of the p53 pathway is an universal event in human cancers. As p53 mutations are rare in de novo acute leukemias, the p53-pathway must be inactivated by other mechanisms instead. The Apoptosis stimulating Protein of p53-2 (ASPP2) is a haploinsufficient tumor suppressor, which we have shown to be attenuated in acute leukemia. We now provide evidence that ASPP2 regulates pathways involved in early hematopoiesis, and attenuated expression perturbs malignant transformation. Gene-chip microarrays were performed on ASPP2+/+ versus +/- mouse embryonic fibroblasts (MEFs) (-/- knockouts are not viable) and pathway analysis was performed using Affimetrix software. ASPP2 expression was silenced in IL3-dependent Ba/F3 pro-B cells and leukemia cell lines using standard siRNA protocols. Cellular proliferation was assessed using XTT-based assays. To evaluate for malignant transformation, long term cell cultures with stably retrovirally silenced Ba/F3 cells (+/- stress inforcement using gamma irradiation, 4x 5Gy) were employed. IL3 weaning was performed as an indicator of autoactivated cellular proliferation, and analysis of chromosomal defects or gene mutations were performed. Microarray mRNA analysis revealed that attenuated ASPP2 expression resulted in significant alterations of pathways involved in mediating cellular growth, proliferation and tissue differentiation. Subanalysis proofed involvement of genes playing a major role in embryogenesis, the development of the hematopoietic system and leukemogenesis (homeobox (HOX) family members, NOTCH, BCL, IRF7 and EGR1). Population doubling times were significantly increased in ASPP2+/- MEFs compared to the parental cells. Modeling ASPP2 attenuation via specific siRNA knockdown in leukemia cell lines (K562 and Kasumi1) resulted in significantly increased cellular proliferation. Similarly, ASPP2-interference in pro-B Ba/F3 cells lead to perturbed proliferation and an increase of polyploid cells with a dramatic change in morphology with megaloid cells, indicating mitotic failure. This effect was even more pronounced after stress induction with daunorubicin. Lentiviral shRNA-ASPP2 stable knock-out was performed in Ba/F3 cells to follow cells in long term cultures for malignant transformation. Again, we confirmed signs of mitotic failure as observed in the siRNA approach. Even more, gamma irradiated ASPP2-lacking strains were successfully IL3 weaned, which indicates autoactivated cellular proliferation. A screen for acquired oncogenic mutations was performed and analyses are ongoing. In summary, we provide evidence that ASPP2 has a pivotal role in early hematopoiesis, and loss of ASPP2 is a driver mechanism to fuel leukemogenesis. Disclosures No relevant conflicts of interest to declare.
Bone Marrow Derived Mesenchymal Cells Secrete Granulopoietic Cytokines upon Danger Signaling
2014-12-06

Abstract Granulopoietic homeostasis is regulated at steady-state to supply sufficient numbers of pooled and circulating neutrophils to maintain barrier function against commensal flora. In addition, upon pathogenic microbial challenge, an increased formation of neutrophils is induced, termed ‘emergency granulopoiesis’. Antibody-mediated reduction of neutrophil numbers in steady-state induces a feedback loop leading to an increase of bone marrow granulopoiesis with expansion of hematopoetic stem and progenitor cells. This feedback loop was demonstrated to depend on TLR4 and TRIF, but not MyD88 signaling (Bugl et al. Blood 2013). In contrast, emergency granulopoiesis was shown to be dependent on MyD88 signaling in endothelial cells (Boettcher et al. Blood 2014). Bone marrow mesenchymal stromal cells (MSC) are niche-forming cells, harboring and regulating hematopoiesis. Upon steady-state neutropenia an increase of niche size was observed. Here we investigated, whether niche-forming MSC act as sensors of pathogen-associated molecular patterns (PAMPs) and induce granulopoietic cytokines to stimulate expansion of adjacent hematopoietic stem and progenitor cells. MSC of C57BL/6 and TLR4-KO mice were cultured in vitro and treated with LPS for 24 hours. Cells were harvested and qRT-PCR for G-CSF, TLR4, MyD88, TRIF, GM-CSF, IL-1β, IL-18 and Casp-1 was performed After treatment with LPS, RNA of granulopoietic cytokines G-CSF and GM-CSF were massively up regulated in MSC of WT mice. Upstream regulating, inflammasome components IL-1ß and caspase-1 RNA levels increased as well, with little changes in IL-18, TLR4, MyD88 and TRIF. Unexpectedly, TLR4-KO MSC up regulated transcription of IL-1β and G-CSF upon LPS stimulation as well, and caspase-1 was found to be strongly up-regulated in unstimulated TLR4-KO compared to WT MSC. In summary, bone marrow stromal cells are found to be PAMP-sensing and secrete cytokines that regulate granulopoiesis. TLR4-independent sensing of LPS by MSC might correspond to the alternative noncanonical inflammasome pathway recently described (Kayagaki et al. Science 2013). Disclosures No relevant conflicts of interest to declare.
The Innate Immune System Favors Emergency Monopoiesis at the Expense of DC Differentiation to Control Bacterial Infections
2014-12-06

Abstract Dendritic cells (DCs) are critical in host defense against infection, bridging the innate and adaptive immune system. Patients with sepsis display reduced circulating and splenic DCs and impaired DC function that may contribute to prolonged immune suppression and exacerbation of infection. However, the mechanisms of pathogen-induced DC depletion remain poorly understood. Here, a mouse model of systemic bacterial infection was employed to analyze the impact of different bacterial pathogens on DC development in vivo. We found that the numbers of bone marrow (BM) hematopoietic progenitors committed to the DC lineages were reduced following systemic infection with different Gram-positive and Gram-negative bacteria. In parallel, a TLR4-dependent increase of committed monocyte progenitors in the BM as well as mature monocytes in the spleen was observed. In line, adoptively transferred FLT3+ myeloid progenitors (MPs) developed preferentially to monocytes at the expense of DCs in infected animals. Analyses performed on mixed BM chimeras suggested that both the reduction of DC progenitors and the induction of monopoiesis following infection were dependent on extrinsic TLR4 signaling driving the secretion of IFN-g regulated chemokines. Consistently, these effects were completely abrogated by suppression of IFN-g signaling. Elevated monocyte numbers in the spleen triggered by infection were due to a CCR2-dependent egress from the BM. In CCR2-deficient mice, in which monocytosis reportedly is abrogated, we observed a significantly increased bacterial load in the spleen and a reduced survival rate, highlighting the importance of monocytes for bacterial clearance. Together, our data provide evidence for a general response of myeloid progenitors upon bacterial infection to enhance monocyte production, thereby increasing the availability of innate immune cells as a first line of defense against invading pathogens. Concomitantly the development of DCs is impaired, which may be responsible for transient immunosuppression in e.g. bacterial sepsis. Disclosures No relevant conflicts of interest to declare.
Activation-Induced Release of the TNF-Family Member BAFF By NK Cells Facilitates Resistance of Chronic Lymphoid Leukemia Cells to Direct and Rituximab-Induced NK Lysis
2014-12-06

Abstract NK cells are cytotoxic lymphocytes that play an important role in the immunosurveillance of leukemia and, due to their ability to mediate antibody-dependent cellular cytotoxicity (ADCC), substantially contribute to the therapeutic benefit of antitumor antibodies like Rituximab. Available data indicate that the ability of NK cells to mediate ADCC is compromised in Chronic Lymphoid Leukemia (CLL), but the underlying mechanisms are still unclear. The TNF family member B cell activating factor (BAFF) was described to be aberrantly produced in mature B cell malignancies and contributes to disease pathophysiology e.g. by acting as a growth and survival signal for CLL cells. Here we report that NK cells express and release BAFF, and NK cell activation, notably including FcγRIIIa stimulation by Rituximab, results in increased secretion of BAFF (but not its close relative APRIL). Expression on the cell surface was neither detectable in resting nor in activated state. NK cell-derived BAFF enhanced the metabolic activity of primary CLL cells and protected CLL cells from chemotherapy-induced cell death. Moreover, exposure to BAFF profoundly diminished direct and Rituximab-induced lysis of primary CLL cells by allogeneic and autologous NK cells, while NK activation and degranulation per se remained unaffected. Notably, sensitivity of CLL cells to both chemotherapeutic treatment as well as direct lysis and Rituximab-induced ADCC of NK cells could be restored by the anti-BAFF antibody Belimumab (Benlysta®), which is approved for the treatment of systemic lupus erythematosus. Thus, our data provide evidence for the involvement of BAFF in the resistance of CLL cells to chemotherapy. Moreover, our results offer a functional explanation for the reportedly compromised ability of NK cells to combat lymphoid as compared to myeloid leukemias as well as their impaired ability to mediate ADCC upon Rituximab treatment in CLL patients. Our findings point to a possible benefit of combinatory approaches employing Rituximab and Belimumab for chemo-immunochemotherapy of B cell malignancies. Disclosures No relevant conflicts of interest to declare.
Brain–machine interfaces in neurorehabilitation of stroke
2014-12-07

Stroke is among the leading causes of long-term disabilities leaving an increasing number of people with cognitive, affective and motor impairments depending on assistance in their daily life. While function after stroke can significantly improve in the first weeks and months, further recovery is often slow or non-existent in the more severe cases encompassing 30–50% of all stroke victims. The neurobiological mechanisms underlying recovery in those patients are incompletely understood. However, recent studies demonstrated the brain's remarkable capacity for functional and structural plasticity and recovery even in severe chronic stroke. As all established rehabilitation strategies require some remaining motor function, there is currently no standardized and accepted treatment for patients with complete chronic muscle paralysis. The development of brain–machine interfaces (BMIs) that translate brain activity into control signals of computers or external devices provides two new strategies to overcome stroke-related motor paralysis. First, BMIs can establish continuous high-dimensional brain-control of robotic devices or functional electric stimulation (FES) to assist in daily life activities (assistive BMI). Second, BMIs could facilitate neuroplasticity, thus enhancing motor learning and motor recovery (rehabilitative BMI). Advances in sensor technology, development of non-invasive and implantable wireless BMI-systems and their combination with brain stimulation, along with evidence for BMI systems' clinical efficacy suggest that BMI-related strategies will play an increasing role in neurorehabilitation of stroke.
Improving Collaboration by Standardization Efforts in Systems Biology
2014-12-08

Collaborative genome-scale reconstruction endeavors of metabolic networks would not be possible without a common, standardized formal representation of these systems. The ability to precisely define biological building blocks together with their dynamic behavior has even been considered a prerequisite for upcoming synthetic biology approaches. Driven by the requirements of such ambitious research goals, standardization itself has become an active field of research on nearly all levels of granularity in biology. In addition to the originally envisaged exchange of computational models and tool interoperability, new standards have been suggested for an unambiguous graphical display of biological phenomena, to annotate, archive, as well as to rank models, and to describe execution and the outcomes of simulation experiments. The spectrum now even covers the interaction of entire neurons in the brain, three-dimensional motions, and the description of pharmacometric studies. Thereby, the mathematical description of systems and approaches for their (repeated) simulation are clearly separated from each other and also from their graphical representation. Minimum information definitions constitute guidelines and common operation protocols in order to ensure reproducibility of findings and a unified knowledge representation. Central database infrastructures have been established that provide the scientific community with persistent links from model annotations to online resources. A rich variety of open-source software tools thrives for all data formats, often supporting a multitude of programing languages. Regular meetings and workshops of developers and users lead to continuous improvement and ongoing development of these standardization efforts. This article gives a brief overview about the current state of the growing number of operation protocols, mark-up languages, graphical descriptions, and fundamental software support with relevance to systems biology.
Loss of Heterozygosity at the CYP2D6 Locus in Breast Cancer: Implications for Germline Pharmacogenetic Studies
2014-12-08

LOH at the CYP2D6 locus is common in breast cancer, resulting in potential misclassification of germline CYP2D6 genotypes. Tumor DNA should not be used to determine germline CYP2D6 genotype without sensitive techniques to detect low frequency alleles and quality control procedures appropriate for somatic DNA.
Growth of Competing Crystal Phases of α-Sexithiophene Studied by Real-Time in Situ X-ray Scattering
2014-12-08

We report on a real-time <em>in situ</em> study of the growth of <em>α</em>-sexithiophene on silicon oxide substrates. Synchrotron-based X-ray diffraction experiments were performed during and directly after the growth in order to monitor the growth process. We observed a coexistence of two different crystal phases for different substrate temperatures. For films prepared at 233 and 308 K a disordered phase (<em>β</em>-phase) seems to be dominant compared to films prepared at 373 K where the so-called low-temperature bulk crystal phase (LT-phase) is dominant. From real-time measurements during growth we observed a temperature and film thickness dependent effect on the fraction of both phases in one sample. At 373 K the film growth begins primarily in the <em>β</em>-phase, and above a certain thickness the film growth proceeds mainly in the LT-phase. However, at 308 K the film growth is dominated by the <em>β</em>-phase for the entire thickness. We show that for kinetically limited growth conditions (high deposition rate and/or low substrate temperature) substrate induced growth effects are dominant.