bluuebunny/crossref_metadata_2025_split huggingface dataset:
Recreating a Human Hematopoietic Stem Cell Niche in Vitro by Unique Stroma Cells from the First Trimester Human Placenta and Fetal Liver
Authors: Magnusson Mattias , Romero Melissa , Prashad Sacha , Van Handel Ben , Aivio Suvi , Huang Andy , Pellegrini Matteo , Mikkola Hanna 
Published: October 2019

Abstract
Expansion of human hematopoietic stem cells (HSCs) ex vivo has been difficult due to limited understanding of their growth requirements and the molecular complexity of their natural microenvironments. To mimic the niches in which human HSCs normally develop and expand during ontogeny, we have derived two unique types of stromal niche cells from the first trimester human placenta and the fetal liver. These lines either support maintenance of multipotential progenitors in culture, or promote differentiation into macrophages. Impressively, the supportive lines facilitate over 50,000-fold expansion of the most immature human HSCs/progenitors (CD34+CD38-Thy1+) during 8-week culture supplemented with minimal cytokines FLT3L, SCF and TPO, whereas the cells cultured on non-supportive stroma or without stroma under the same conditions differentiated within 2 weeks. As the supportive stroma lines also facilitate differentiation of human hematopoietic progenitors into myeloid, erythroid and B-lymphoid lineages, we were able to show that the expanded progenitors preserved full multipotentiality during long-term culture ex vivo. Furthermore, our findings indicate that the supportive stroma lines also direct differentiation of human embryonic stem cells (hESC) into hematopoietic progenitor cells (CD45+CD34+) that generate multiple types of myeloerythroid colonies. These data imply that the unique supportive niche cells can both support hematopoietic specification and sustain a multilineage hematopoietic hierarchy in culture over several weeks. Strikingly, the supportive effect from the unique stromal cells was dominant over the differentiation effect from the non-supportive lines. Even supernatant from the supportive lines was able to partially protect the progenitors that were cultured on the non-supportive lines, whereas mixing of the two types of stroma resulted in sustained preservation of the multipotential progenitors. These results indicate that the supportive stroma cells possess both secreted and surface bound molecules that protect multipotentiality of HSCs. Global gene expression analysis revealed that the supportive stroma lines from both the placenta and the fetal liver were almost identical (r=0.99) and very different from the non-supportive lines that promote differentiation (r=0.34), implying that they represent two distinct niche cell types. Interestingly, the non-supportive lines express known mesenchymal markers such as (CD73, CD44 and CD166), whereas the identity of the supportive cells is less obvious. In summary, we have identified unique human stromal niche cells that may be critical components of the HSC niches in the placenta and the fetal liver. Molecular characterization of these stroma lines may enable us to define key mechanisms that govern the multipotentiality of HSCs.
Poor Outcome for Children and Adolescents with Progressive Disease or Relapse of Lymphoblastic Lymphoma - a Report of the BFM Group
Authors: Burkhardt Birgit , Reiter Alfred , Landmann Eva , Lang Peter J. , Lassay Lisa , Dickerhoff Roswitha , Lakomek Max , Henze Guenter , von Stackelberg Arend 
Published: October 2019

Abstract
Background/Objectives: Little is known about the outcome of pediatric patients with lymphoblastic lymphoma (LBL) who suffer form progressive disease or relapse.
Patients and Methods: We analyzed the pattern of LBL-relapses after current NHL-BFM-frontline therapy between 4/90 and 3/03. Relapse therapy was according to ALL-Relapse-BFM protocols or ALL-BFM protocols for high-risk patients.
Results: 28 of 251 registered T-LBL-patients (11%) and six of 73 pB-LBL-patients (8%) suffered from relapse. Of the 28 T-LBL-patients, one died from infection during relapse-chemotherapy, 18 failed to achieve stable remission and died from disease-progression, and nine reached allogeneic stemcell transplantation (SCT). Two of these nine SCT patients died from transplantation-associated toxicity, three died from disease-progression and four are still alive. The patients are in 2nd remission of their lymphoma for 48, 68, 125 and 131 months respectively after allogeneic SCT. One of the four patients developed colon adenocarcinoma 47 months after SCT. Of the six relapsed pB-LBL patients one died due to toxicity of relapse-chemotherapy, two died from disease-progression after chemotherapy and three received allogeneic SCT. Of these, two died from subsequent disease-progression while one patient is still alive 57 months after allogeneic SCT.
Conclusions: Outcome of LBL-patients with relapse during or after current intensive 1st line therapy is poor. More than 50% of these patients failed to achieve remission to intensive 2nd line chemotherapy. Consolidation by allogeneic SCT may offer a cure for those who reach second remission.
Treatment of Primary CNS Lymphoma in the Elderly, a Multicenter Retrospective Analysis
Authors: Bromberg Jacoline E.C. , Doorduyn Jeanette , Schuurmans Macha , Poortmans Philip , Taphoorn Martin J.B. , Seute Tatjana , Dekker Adriaan W. , Enting Roelien H. , van Imhoff Gustaaf , van Norden Yvette , van den Bent Martin 
Published: October 2019

Abstract
Patients with primary CNS lymphoma (PCNSL) are preferably treated with high-dose Methotrexate (HD-MTX)-based chemotherapy followed by consolidation radiotherapy in many centers. As elderly patients have an increased risk of complications with this approach, they are frequently treated with chemotherapy or radiotherapy alone. Little is known about the efficacy and toxicity of either of these treatments in elderly patients outside clinical studies. We analysed all patients aged 60 or above referred with PCNSL to 5 Dutch centers between 1998 and 2007. 110 patients were identified. We excluded: patients who were not treated because of a poor condition (n=25), patients with EBVrelated NHL (n=3), patients with PCNSL confined to the eyes (n=3), and patients with missing information on follow-up (n=5). The remaining 74 patients had a median age of 65 years (range 60–82), and a median KPS of 70% (range 30–100). Twenty-nine of them were treated with radiotherapy only, 19 with chemotherapy only and 26 with both; 19 of these 26 received radiotherapy after failure of chemotherapy. Median KPS was 70 in both single treatment modality groups and 80 in the group receiving both modalities. The response rate (CR or PR) was 69% (20/29) in patients treated with radiotherapy only and 63% (12/19) in patients treated with chemotherapy only. Timing of both response evaluation and radiotherapy after chemotherapy were highly variable in the group treated with both modalities, therefore these patients are only included in the overall survival analyses. Median overall survival (OS) was 20 months: 7 months for patients treated with radiotherapy only, 23 months for those treated with chemotherapy only, and 31 months for combined modality treatment (p=0.01). The KPS was a significant prognostic factor for as well PFS as OS (p<0.001): median PFS and OS were 3 and 4 months respectively in patients with KPS < 70 and 18 and 25 months in patients with a KPS ≥ 70. Forty of the 45 patients receiving chemotherapy were planned for treatment with a MTX dose of 3g/m2. There were 2 toxic deaths. Ten of the 40 patients received delayed or reduced doses, or aborted chemotherapy because of toxicity. Delayed encephalopathy was reported in 15 patients: 7/30 patients after radiotherapy, 1/19 after chemotherapy only and 7/26 after combined treatment. Five died as a consequence of the encephalopathy.
Conclusion: Performance status is the most important single variable determining prognosis in elderly patients. Overall survival after HD-MTX-based treatment for PCNSL in the elderly appears to approach survival obtained in younger patients, provided the performance status is adequate. Treatment related mortality of HD-MTX-based chemotherapy seems not to be increased in older patients.
Inhibition of Cdk4/6 by PD 0332991 Results in Abrogation of Osteoclast Formation
Authors: Feng Rentian , Huang Xiangao , Roodman G. David , Chen-Kiang Selina , Lentzsch Suzanne 
Published: October 2019

Abstract
Multiple myeloma (MM) is characterized by increased osteoclast activity resulting in bone destruction and development of lytic lesions. Despite overall survival achieved by new treatment modalities, new drugs are required to specifically and effectively inhibit bone destruction. PD 0332991 is a selective small molecule inhibitor of cyclin-dependent kinase (Cdk)4 and Cdk6 with oral bioavailability. We have demonstrated recently that inhibition of Cdk4/6 by PD 0332991 effectively controls MM tumor expansion in animal models and sensitizes chemoresistant MM tumor cells to bortezomib killing despite protection by bone marrow stromal cells. Currently clinical phase I/II trials are ongoing to test the efficacy of the combination of PD 0332991 and bortezomib.
Selective inhibition of Cdk4/6 by PD 0332991 leads to sustained G1 arrest but not apoptosis, and this appears to be cell type-specific. Consistent with these findings, PD 0332991 is well tolerated in MM patients. On this basis, we address the possibility that PD 0332991, alone and in combination with bortezomib, may inhibit osteoclastogenesis, by culturing non-adherent mononuclear bone marrow cells from MM patients cultured in the presence of M-CSF and RANKL for three weeks. Treatment of human osteoclast cultures with PD 0332991 for 3 weeks decreased osteoclast formation in a dose-dependent manner with an IC50 50 nM. The combination of PD 0332991 and bortezomib led to synergistic inhibition of osteoclast formation and completely abrogated osteoclastogenesis with low dose PD 0332991 (25 nM) and bortezomib (2 nM). Furthermore, we show in a time course study that treatment with PD 0332991 for the first week, but not the second or third week, was sufficient to inhibit osteoclast formation. PD 0332991 is the only known selective inhibitor of Cdk4 and Cdk6, which at concentration below 5 uM does not cross react with at least 38 kinases or induce apoptosis. Taken together, our data suggest that by inducing G1 arrest and inhibiting progenitor expansion, PD 0332991 is a powerful and selective inhibitor for osteoclastogenesis. We propose that targeting Cdk4/6 with PD 0332291 in combination therapy is a promising therapeutic strategy to improve bone integrity in MM.
Thalidomide + Dexamethasone as Maintenance after Single Autologous Stem Cell Transplantation Improves Progression-Free Survival (PFS) in Advanced Multiple Myeloma. A Prospective Brazilian Randomized Trial
Authors: Maiolino Angelo , Hungria Vania T. , Oliveira-Duarte G. , Oliveira LC , Mercante DR , Miranda Ecm , Quero A. , Peres AL Miguel , Barros Jc , Tanaka P. , Magalhães RP , Rego Eduardo M. , Nucci M. , Lorand-Metze Irene , Lima CSP , Zalcberg I. , Braggio E. , De Souza Carmino 
Published: October 2019

Abstract
Introduction: Autologous stem cell transplantation (ASCT) remains the mainstay of treatment of multiple myeloma (MM) in patients <65 years old. However, most patients relapse after ASCT suggesting that additional treatment is needed. The Brazilian Multiple Myeloma Group designed a study to evaluate the impact of thalidomide maintenance after ASCT.
Methods: From October 2003 to July 2008, 212 untreated patients <70 years old were enrolled in a prospective randomized multicenter study. All patients signed an informed consent and the protocol was approved by the Ethical Committees of each center. The treatment consisted of 3 phases:
induction with 3–5 cycles of VAD; high-dose cyclophosphamide (4g/m2) plus G-CSF for stem cell mobilization;
(3) melphalan 200 mg/m2 and ASCT. On day +60 post ASCT patients were randomized to receive dexamethasone (40 mg/d × 4 days every 28 days) with (arm A) or without (arm B) thalidomide (200 mg daily) for 12 months or until disease progression.
Results: The median age was 55 years (27–70), 52% were male, the median serum beta-2 microglobulin was 3.66 mg/dl, 33% were ISS stage 3, 36% were ISS stage 2 and 24% had deletion of chromosome 13. In July of 2008, 93 patients (44%) were randomized: 54 in arm A and 39 in arm B. Reasons for non-randomization were: treatment related deaths during phases 1–3 (n= 39), disease progression (n= 22), ineligible or refused ASCT (n= 7), SMD after ASCT (n= 1), protocol violation (n= 3), abandoned (n= 19), and still in phases 1–3 (n= 28). Clinical characteristics of each group were similar. The median follow-up from diagnosis was 15 months. PFS in arms A and B were 42% (95% confidence interval [CI] 22–62) and 25% (95% CI 5–45), p= 0.07. A multivariate analysis that included baseline serum beta-2-microglobulin and deletion of chromosome 13 showed that maintenance with thalidomide was significantly associated with better PFS (hazard ratio 2.43, 95% CI 1.10–5.35, p=0.03). Overall survival was 65% in arm A (95% CI 35–95) and 74% in arm B (95% CI 44–100), p= NS.
Conclusions: A high proportion of MM in Brazil has advanced disease at diagnosis, and this explains the high number of patients who did not reach the maintenance phase. This study shows that the addition of thalidomide to dexamethasone improves PFS after a single ASCT.
Lenalidomide as Salvage Therapy after Allogeneic Stem′Cell Transplantation in Multiple Myeloma
Authors: Lehmann Friederike , El-Cheikh Jean , Zabelina Tatjana , Ayuk Francis , Wolschke Christine , Atanackovic Djordje , Bacher Ulrike , Zander Axel R. , Blaise Didier , Mohty Mohamad , Kroeger Nicolaus 
Published: October 2019

Abstract
Lenalidomide is an immunmodulatory drug, orally administered once daily, which is effective in relapsed multiple myeloma (MM). Here, we evaluated the efficacy and toxicity of lenalidomide in 24 MM patients with relapsed disease after allogeneic stem cell transplantation (allo-SCT). Median age was 59 (range, 37–70) years. The series included 8 females and 16 males. Prior to allo-SCT, all patients were heavily pretreated with a median of 6 chemotherapy cycles including autologous and allo-SCT in all patients. Also, prior to lenalidomide, salvage treatment included donor lymphocyte infusions (DLI) in 18 pts,, thalidomide in 11 pts and bortezomib in 13 pts. Lenalidomide was given at 15mg (n=4) or 25 mg (n=20) orally once daily on day 1–21 every 28 days and in 20 patients in combination with dexamethason.. No prophylactic anticoagulation was used. The median number of completed cycles was 5 (range 2–17). Myelotoxicity according NCI criteria was the primarily and major encountered side effect (leukopenia: 4% grade 4, 21% grade 3, 17% grade 2, thrombopenia: 17% grade 3, 29% grade 2) and led to dose reduction in 54% of the patients. Infectious complications were observed in 50%. Non-hematological toxicity consisted of cramps (n=9), fatique (n=5) and constipation (n=2). Thrombembolic complications (cerebral infarction) were observed in one patient, who received concomitant corticosteroid treatment for acute graft-vs.-host disease (GvHD), but neurological symptoms resolved completely. GvHD of the skin under lenalidomide treatment was seen in 3 patients (one grade 2, and 2 grade 1), with one case occurring shortly after an additional DLI.. Objective remission was achieved in 66% of the patients (CR: 8%, VGPR: 8%, PR: 50%) and stable disease (SD) in 13% of the patients, while in 21% progressive disease was noted. Prior treatment with thalidomide or with bortezomib did not influenced the rate of CR/PR. Surprisingly, patients with del 13q14 achieved a higher CR/PR rate than those without del 13q14 (p=0.02). The median time to progression was 9.7 months (95% CI: 7.5–11.9) and the median overall survival was 19.9 months (95% CI: 17.3–22.5). Lenalidomide is effective in relapsed patients with MM after allo-SCT. Major toxicity is myelotoxicity, which required dose reduction in the majority of patients. The optimal dose of lenalidomide after allo-SCT has to be investigated.
In Vitro and in Vivo Inhibition of JAK2 Signaling by Potent and Selective JAK2 Inhibitor
Authors: Markovtsov Vadim , Tonkin Elizabeth , Fang Shuling , Liu Chiang , Gelman Marina , Lang Wayne , Romero Jason , McLaughlin John , Bhamidipati Somasekhar , Clough Jeffrey , Singh Rajinder , Low Caroline , Reitsma Andrea , Taylor Vanessa , Siu Stacey , Park Gary , Sweeney David , Pine Polly , Torneros Allan , Clemens George , Duan Matt , Daniel Ruby , Payan Donald , Holland Sacha , Hitoshi Yasumichi 
Published: October 2019

Abstract
Recent advances in understanding the role of JAK2 V617F mutation in Bcr-Abl negative myeloproliferative (MPD) diseases pathogenesis opened up a possibility to develop highly targeted therapies against these debilitating ailments. We used a Ba/F3 cell line expressing the V617F mutant of JAK2 to screen a focused small molecule library for potential inhibitors of JAK2 V617F-dependent proliferation. Further extensive SAR of initial hits resulted in identification of R723, a potent and selective JAK2 inhibitor. This molecule is strongly antiproliferative (IC50 130–200 nM) against mouse BaF3 cells used for initial screening as well as against human UKE1 and SET2 cell lines harboring the same mutation. On the other hand, R723 has only weak activity in IL2-dependent (i.e. JAK1/JAK3-dependent) proliferation assays performed with human primary T (IC50 1300 nM) and mouse T-cell leukaemia CTLL2 cells (IC50 600 nM). A 10 to 20 fold cell-based selectivity of R723 was further confirmed by measuring inhibition of constitutive STAT5 phosphorylation in SET2 and BaF3 cells versus inhibition of IL-2 inducible STAT5 phosphorylation in human primary T and mouse CTLL2 cells using FACS-based approach. Compound R723 has low nonspecific antiproliferative activity against JAK2-independent MOLT4, A549 and H1299 cell lines with an IC50 ranging from 4 to 6 uM. The molecule has been also proven to be potent (IC50 of 2 nM against JAK2 in biochemical assay) and highly selective (window of more than 500 fold over JAK1 and 10 fold over JAK3) inhibitor of JAK2 kinase in vitro. Moreover, when tested in biochemical assay against a panel of more than 200 kinases at a concentration of 20 nM (IC90 for JAK2), R723 inhibited none of them. The selectivity of R723 was further confirmed using a variety of cell-based assays probing T-, B- and mast cell activation. Compound R723 was further evaluated in a stress-induced erythropoiesis mouse model, where kinetics of EPO-dependent hematocrit recovery from phenylhydrazine-induced anemia was assessed. Significant delay in recovery was observed at doses of 75 and 100 mg/kg bid indicating strong compound effect on EPOR signaling in vivo. The result could not be attributed to general toxicity effects as 14 day toxicology study did not identify any abnormalities at doses tested. As a result, R723 could become the basis for next generation of potent and selective compounds targeting JAK2-dependent myeloproliferative diseases.
Differential Biological Properties and Signaling Effects of Different JAK2 Alleles
Authors: Mohi M. Golam , Yan Dongqing , Zou Haiying 
Published: October 2019

Abstract
JAK2, a member of the Janus family of non-receptor protein tyrosine kinases, acts as an important mediator of cytokine receptor signaling and plays a critical role in hematopoiesis. Somatic mutations in JAK2 have been identified in a spectrum of myeloproliferative disorders (MPD). A specific point mutation (V617F) in the pseudokinase domain (JH2) of JAK2 has been identified in most patients with polycythemia vera (PV) and 50–60% patients with essential thrombocythemia (ET) and primary myelofibrosis (PMF). Although JAK2V617F is the predominant allele associated with PV, ET and PMF, other activating alleles of JAK2 also have been identified in distinct MPD. Somatic mutations in the exon 12 (linker region between JH2 and JH3) of JAK2 are associated with a distinct type of PV characterized by isolated erythrocytosis. Another activating mutation (T875N) in the kinase domain (JH1) of JAK2 has been identified in a cell line derived from acute megakaryoblastic leukemia (AMKL) patient, and expression of JAK2T875N in murine bone marrow induces a MPD with features of AMKL. Thus, different activating JAK2 alleles are associated with different disease phenotypes. The basis for the differences in the in vivo effects of different JAK2 alleles remains unclear. To understand the biological and signaling effects of these JAK2 mutants, we have generated Ba/F3-EpoR cell lines expressing JAK2WT, JAK2V617F, JAK2 exon 12 mutant K539L or JAK2T875N. Expression of JAK2V617F, JAK2K539L or JAK2T875N in Ba/F3-EpoR cells resulted in IL-3 independence, whereas JAK2WT failed to grow in absence of IL-3. We observed significantly increased proliferation of JAK2T875N expressing cells compared to cells expressing either JAK2V617F or JAK2K539L in the absence of cytokine. Moreover, expression of JAK2T875N caused increased transformation of Ba/F3-EpoR cells in a colony assay. Biochemical analysis revealed that the kinase activity of JAK2K539L was higher than JAK2V617F but comparable to JAK2T875N. More importantly, significant differences in signaling downstream of these JAK2 mutants were observed. Expression of JAK2T875N resulted in increased phosphorylation of Stat3, Stat5, Gab2, Akt, and Erk/MAPK and induction of Pim1 and Pim2 compared to JAK2V617F and JAK2K539L mutants. Although JAK2K539L exhibited more kinase activity than JAK2V617F but it was less potent in activation of downstream signaling molecules, such as Stat5, Gab2, Erk/MAPK. Variable association of mutant JAK2 with EpoR was also observed, with JAK2K539L being the most and JAK2T875N being the least associated with EpoR. These results strongly suggest that the biological properties and signaling effects of JAK2 alleles are different, and they may interact differentially with cytokine receptor, which might contribute to the differences in the disease phenotype.