bluuebunny/crossref_metadata_2025_split huggingface dataset:
Viral Infection Sentinel Rig-I Maintains Hematopoietic Stem Cell Function Through Regulating DNA-Damage Response
Authors: Zhang Wu , Ding Meng-Lei , Li Xian-Yang , Guo He-Zhou , Zhang Hong-Xin , Chen Sai-Juan , Zhu Jiang 
Published: October 2019

Abstract
Throughout life hematopoietic stem cells (HSCs) have to cope with various kinds of insults from inflammation to DNA damage constantly to maintain the integrity of stemness. It is possible that certain core factors are commonly implicated in the maintenance of HSC pool and function under discrete physiological and pathological conditions. However, the underlying mechanisms remain largely unexplored. Previous works have demonstrated that retinoic acid inducible gene I (Rig-I) plays an essential role in recognizing viral RNA and activating type I IFN transcription, but whether Rig-I is involved in the core program governing HSCs’ behaviors is unclear. Here, we report that in the steady status Rig-I deficiency significantly increased HSC number by dysregulating the cell-cycling status of HSCs in mice. However, HSCs in Rig-I-/- mice were actually more sensitive to genotoxic treatments such as irradiation as compared to wild type HSCs, causing more Rig-I-/- mice to die of hematopoietic exhaustion. In accordance, HSC transplantation assays showed a significant impact of Rig-I loss on the hematopoietic regeneration capacity. Mechanistically, we found that Rig-I represented a pivotal component of the molecular pathways that mediate DNA-damage response and the repair of DNA lesions. Taken together, these data indicate a crucial role of innate immunity-regulatory factor Rig-I in the maintenance of HSCs.

Disclosures:
No relevant conflicts of interest to declare.
Germline Events In GFI1 In Myelodysplastic Syndrome
Authors: Thota Swapna , McMahon Sarah , Makishima Hideki , Przychodzen Bartlomiej P , Guinta Kathryn M , Dienes Brittney , Hosono Naoko , Sekeres Mikkael A. , Maciejewski Jaroslaw P. 
Published: October 2019

Abstract
Germ line mutations in growth factor independent-1 (GFI1) have been described in a small subset of patients (pts) with severe congenital neutropenia. Subsequently, the GFI136N polymorphism, present in 3-5% of controls, has been found overrepresented (11%) in pts with primary (p) acute myeloid leukemia (AML), conveying 1.6 fold risk of development of AML. Mutant GFI136S and N variants lack affinity to HOXA9 (overrepresented in corresponding AML cases), shows increased proliferative potential in vitro and accelerates RAS-driven myeloproliferative neoplasm (MPN) disease in mice.
Whole exome next generation (WE NGS) technology facilitates comprehensive screens for the presence of both somatic and germ line genetic alteration. In this study, we used NGS to search for germline variants of the GFI1 gene. We screened 140 pts (mean age 66.8 years, range 44-85) with MDS and related disorders (MDS/MPN and secondary (s) AML) for the presence of GFI1 variants. We found non-synonymous variants in 11 cases (8%), including the previously described pathogenic p.S36N (n=8), p.P107A (n=2), or p.L400F (n=1), while the corresponding frequencies for these alterations were .04 and .001, .002 in the general population. This frequency appears comparable or higher to those previously reported for pAML, but our screen of the TCGA AML cohort, perhaps due to very low coverage for this gene, did not reveal any GFI1 polymorphisms. We next focused on the clinical features of altered GFI1 carriers. A significant proportion of GFI1 cases were younger (age<60 years) 45% (5/11) compared to 19% (p=.05) for wild type (WT) and predominantly male (82% vs. 52%, p=.02). MDS and sAML and MDS/MPN were present in 4, 3 and 4 pts, respectively. Normal cytogenetics at presentation was present in 64% vs. 43% (p=0.22). The availability of the somatic mutational profile allowed us to investigate whether specific genes are more commonly mutated in GFI1 variant cases. Among the 100 most commonly mutated genes, somatic PTPN11 (18% vs. 2%, p=.09), ASXL1 (18% vs. 8% p=0.2), SF3B1 (18% vs. 9%, p=0.3) were the most frequently encountered. Response rate to therapy with hypomethylating agents amongst carriers of GFI1 variants was 50% compared to 35% among WT (p=.32). The mean overall survival of the GFI1mutants was also higher compared to WT (40 vs. 33.6m).
In sum, our results demonstrate that potentially pathogenic GFI1 mutations are present in increased frequency in younger pts with MDS and thus may constitute a new predisposing factor for MDS and related myeloid neoplasms.

Disclosures:
Makishima: AA & MDS international foundation: Research Funding; Scott Hamilton CARES grant: Research Funding. Maciejewski:NIH: Research Funding; Aplastic anemia&MDS International Foundation: Research Funding.
In Vivo RNAi Screening Identifies HDAC4 As a Mediator Of Chemoresistance In Acute Myeloid Leukemia
Authors: Lettermann Stephanie , Agelopoulos Konstantin , Rohde Christian , Lindtner Beate , Marek Linda , Hempel Georg , Stelljes Matthias , Berdel Wolfgang E. , Kurz Thomas , Müller-Tidow Carsten 
Published: October 2019

Abstract
The majority of AML patients still relapse, despite intensive chemotherapy. A subset of more chemoresistant leukemia cells might be responsible for this phenomenon. These relapse-initiating cells might differ epigenetically from the more chemosensitive leukemia bulk. Since interaction of leukemic cells with the niche might contribute to chemoresistance, we decided to perform an in vivo RNAi screen for modulators of chemoresistance. We constructed a focussed shRNA library with ∼400 constructs that target 142 genes involved in stem cell functions, leukemogenesis and epigenetic regulation. Myc/Bcl2 induced murine leukemias were retrovirally transduced and injected into sublethally irradiated syngeneic mice. Mice (n=24) were either treated with Cytarabine, Azacytidine, Decitabine, or vehicle. Upon signs of leukemia, DNA was extracted and the shRNA pool was PCR-amplified from bone marrow, spleen and liver of each individual mouse. Overall, 61 libraries were sequenced with more than 500-fold coverage of each construct. Suppression of HDAC4, Pik3r1, Atr, Ccna2 and HDAC1 significantly enhanced sensitivity towards Cytarabine treatment. Histone deacetylase 4 (HDAC4) was identified as a top candidate since it enhanced the efficacy of all three drugs. It was depleted more than sixteen-fold upon Cytarabine treatment. HDAC4 suppression by the specific shRNAs was confirmed by real-time RT-PCR and western blot analysis. In a competitive re-transplantation assay in vivo, HDAC4 suppression inhibited leukemic growth. Further, we analyzed inhibition of HDAC4 by LMK235, a novel and specific inhibitor of HDAC4 and 5 in human HL60 leukemia cells. Synergistic inhibition was demonstrated for LMK235 and Cytarabine in proliferation assays and in colony formation assays. These findings demonstrate that in vivo RNAi screening for therapeutic efficacy is feasible. HDAC4 might be an important target to enhance efficacy of anti-leukemic drugs.

Disclosures:
No relevant conflicts of interest to declare.
Prevention Of Minimal Residual Disease In Ph+ ALL
Authors: Appelmann Iris , DeStanchina Elisa , Carbonetti Gregory , Chen Chong , Lowe Scott W. , Sherr Charles J. 
Published: October 2019

Abstract
Aggressive Philadelphia chromosome-positive (Ph+) acute lymphoblastic leukemia (ALL) that genetically and phenotypically mimics the human disease can be induced by the introduction of cultured p185 (BCR-ABL)-expressing Arf-null pre/pro-B cells into healthy, unconditioned syngeneic mice. Only 20 polyclonal donor cells are sufficient to induce lethal ALL within 30 days of their IV administration, indicating that BCR-ABL expression and Arf inactivation are sufficient to guarantee leukemogenesis in healthy recipient animals. Leukemic mice enter transient remission in response to treatment with potent second generation tyrosine kinase inhibitors (TKI) such as dasatinib (SprycelTM). However, like human patients with Ph+ ALL, the continuously treated animals ultimately relapse with the emergence of leukemic clones containing clinically relevant BCR-ABL mutations, the nature of which depends upon the intensity of TKI treatment. Premature withdrawal of dasatinib when animals are in remission results in re-emergence of leukemia; surprisingly, leukemic B cells recovered from these animals lack BCR-ABL mutations and remain sensitive to dasatinib ex vivo. Hence, minimal residual disease depends upon salutary signaling within the hematopoietic microenvironment. In agreement, the response to TKI therapy can be significantly improved by abrogating cytokine signaling through a knockdown of the common gamma chain of the cytokine receptor. Administration of the Janus kinase (JAK) inhibitor ruxolitinib (Jakafi™) mimics this response. Although ruxolitinib demonstrated no anti-leukemic activity of its own, the overall survival of leukemic mice inoculated with 200,000 p185+ Arf-/- pre/pro-B cells was significantly extended after administration of a targeted combination therapy of ruxolitinib and dasatinib in comparison with mice treated with dasatinib alone. Addition of dexamethasone further reduced the leukemic burden, prevented CNS relapse, and led to prolonged survival. This implicates prevention of minimal residual disease and relapse by a non-toxic combination of targeted treatments. These studies have provided a rationale for a Phase I/II clinical trial employing these agents, particularly in older patients who are ineligible for bone marrow transplantation or do not tolerate cytotoxic chemotherapy.

Disclosures:
Lowe: Blueprint Medicines: Consultancy; Constellation Pharmaceuticals: Consultancy; Mirimus Inc.: Consultancy.
Treatment With G-CSF Reduces Acute Myeloid Leukemia (AML) Blasts Viability In Presence Of Bone Marrow Stroma
Authors: Nomdedeu Meritxell , Pratcorona Marta , Díaz-Beyá Marina , Calvo Xavier , Lara-Castillo Mari Carmen , Esteban Daniel , Rozman Maria , Costa Dolors , Esteve Jordi , Risueño Ruth M. 
Published: October 2019

Abstract

Background
The simultaneous administration of G-CSF and chemotherapy as a priming strategy has resulted in a clinical benefit in determined subsets of patients diagnosed with acute myeloid leukemia (AML) (Löwenberg et al, NEJM 2003; Pabst T, et al, Blood 2012). However, the mechanism responsible for this anti-leukemic effect is not fully characterized. We hypothesize that the clinical benefit may occur at least partially by the effect of G-CSF on leukemic stem cells (LSC).

Objective
The main goal of this project was to determine the effect of G-CSF on primary AML samples in vitro, especially on LSCs.

Methods and patients
Peripheral blood mononuclear cells (PBMC) from 10 AML patients were treated with G-CSF at increasing doses, alone or in co-culture with HS-5 stroma cells. Cell viability (7-AAD -eBioscience- cell death exclusion and volumetric cell counting) and surface phenotype was determined by flow cytometry (FACSVerse, BD) 72 hours after treatment. Data were analyzed using the FlowJo (Trastar) software. For clonogenicity assays, AML primary samples were treated for 18 hours with G-CSF at increasing concentrations and cultured in H4034 Optimum MethoCult (StemCell Technologies) for 14 days. Colonies were counted based on cellularity and morphology criteria.

Results
G-CSF treatment showed no effect on cell viability of the bulk leukemic population or on the CD34 + immature subpopulation. A dose-dependent increase in CXCR4 surface expression was observed, reaching a 1.4-fold of change at the highest concentration of G-CSF (100 μg/mL). In contrast, treatment of leukemia cells with G-CSF in the presence of stroma cells reduced the overall cell viability. Thus, a 32% decrease of cell viability was measured at the highest concentration used (p = 0.0006), while no significant changes in the frequency of each leukemic subpopulations were observed. Clonogenic capacity was significantly reduced in a dose-dependent manner upon treatment with G-CSF, achieving a 41% reduction at the highest G-CSF concentration (100 μg/mL).

Conclusions
G-CSF reduces the viability of leukemic cells when these cells are in co-culture with the HS-5 stroma cell line, suggesting that the presence of stroma cells is required for the cytotoxical effect of G-CSF on the blast population. Interestingly, G-CSF treatment decreased the clonogenic capacity of AML samples, therefore suggesting that G-CSF exerts its effect at least partially on LSCs. Our findings support the design of studies to explore new strategies of chemotherapy priming in AML patients.

Disclosures:
No relevant conflicts of interest to declare.
Clinical Efficacy and Safety Of Dasatinib For Newly Diagnosed Chronic Myeloid Leukemia In Chronic Phase In Japan
Authors: Yamaguchi Kohei , Murai Kazunori , Ito Shigeki , Akagi Tomoaki , Ogawa Kazuei , Meguro Kuniaki , Inomata Mitsue , Watanabe Reiko , Miyagishima Takuto , Wakasa Kentaro , Shindo Motohiro , Tsukushi Yasuhiko , Kubo Kohmei , Ishida Yoji 
Published: October 2019

Abstract

Background
Dasatinib is a second-generation BCR-ABL inhibitor that has a 325-fold higher potency than imatinib and a 16-fold higher potency than nilotinib in vitro. The previous report from the global DASISION trial showed dasatinib resulted in significantly higher and faster rates of complete cytogenetic response (CCyR) and major molecular response (MMR) compared with imatinib. We conducted a phase II study to evaluate the efficacy and safety of dasatinib in patients with newly diagnosed chronic-phase chronic myeloid leukemia (CML-CP) in Japan.

Methods
Eighty newly diagnosed CML-CP patients were include in this study. Patients received dasatinib 100mg once daily. Treatment was continued until disease progression or unacceptable toxicity. Primary end point was the rate of major molecular response (MMR) by 12 months. MMR defined as a BCR-ABL transcript level of 0.1% or lower on the International scale by means of a real-time quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) in peripheral blood. Secondary end points were the rate of complete cytogenetic response (CCyR) by 12 months, the rate of MR4.5 (either (i) detectable disease with <0.0032% BCR-ABL1 IS or (ii) undetectable disease in cDNA with >32,000 ABL1 transcripts in the same volume of cDNA used to test for BCR-ABL1) by 12 months and adverse events of dasatinib (UMIN #000006358).

Results
Eighty newly diagnosed CML-CP patients were included in this study. All except one patient administered dasatinib 100 mg once daily. One patient was withdrawal before administration of dasatinib. So far, there were 71 patients with 6 months follow-up and 51 patients with 12 months follow-up. The estimated MMR rates were 69.5 % (95%CI, 58.7-80.3 %) by 6 months and 82.7% (95%CI, 73.0-92.4 %) by 12 months. The estimated MR4.5 rates were 27.1 % (95%CI, 16.7-37.5 %) by 6 months and 48.9% (95%CI, 36.0-61.7 %) by 12 months. Only 6 patients were withdrawal because of adverse event (5 patients) and ineffectiveness (1 patient).

Conclusion
Dasatinib treatment results in higher rates of molecular responses in newly diagnosed CML-CP patients in Japan. Dasatinib as the first-line agent might be acceptable for CML-CP patients because of better clinical efficacy and less toxicity.

Disclosures:
No relevant conflicts of interest to declare.
Deferasirox In The Treatment Of Iron Overload During Myeloproliferative Neoplasms (MPN)
Authors: Latagliata Roberto , Montagna Chiara , Porrini Raffaele , Leonetti Sabrina Crescenzi , Niscola Pasquale , Ciccone Fabrizio , Spadea Antonio , Breccia Massimo , Rago Angela , Spirito Francesca , Cedrone Michele , De Muro Marianna , Montanaro Marco , Andriani Alessandro , Bagnato Antonino , Montefusco Enrico , Cimino Giuseppe , Alimena Giuliana 
Published: October 2019

Abstract

Background
Deferasirox is an oral iron chelator widely employed in the treatment of iron overload during thalassemic syndromes and myelodysplastic syndromes.

Aim
At present, very few data are available on the efficacy and safety of a treatment with deferasirox in patients with Ph- Myeloproliferative Neoplasms (MPN) and transfusional requirement.

Methods
To address this issue, we report here on 23 patients (M/F 17/6) with MPN and iron overload secondary to transfusional requirement enrolled in the database of our regional cooperative group who received a treatment with deferasirox. Of them, 20 had a primary Myelofibrosis, 2 a post Essential Thrombocythemia myelofibrotic phase and 1 a post Polycythemia Vera myelofibrotic phase.

Results
The main features of the patients at diagnosis and at baseline of deferasirox treatment are reported in the Table:
Treatment with deferasirox was started after a median interval from diagnosis of 9.8 months (IR 6.7 – 21.7) and from transfusion requirement of 7.3 months (IR 5.7 – 15.3). Starting deferasirox dose was 1,500 mg/day in 11 patients, 1,250 mg/day in 4 patients, 1,000 mg/day in 7 patients and <1,000 mg/day in 1 patient. All patients were evaluable for toxicity: extra-hematological toxicity was reported in 12/23 patients and consisted of gastro-intestinal symptoms in 6 patients, renal impairment in 4 patients and skin reactions in 2 patients. A dose reduction/temporary discontinuation was needed in 11 cases, but only 1 patient went off treatment due to recurrent renal toxicity. Eighteen patients were considered evaluable for response (≥ 6 months of treatment) and 5 were too early. As to the iron overload decrement, after a median treatment period of 14.4 months (IR 7.1 – 21.3) 2 patients achieved ferritin levels < 500 ng/ml, 7 patients ferritin levels < 1,000 ng/ml and 9 patients did not have any ferritin reduction. As to hematological improvement, 5/18 patients showed an unexpected and persistent rise of Hb levels > 1.5 g/dl, with disappearance of transfusional requirement in 3 cases.

Conclusions
Treatment with deferasirox is feasible and effective in MPN with iron overload. Moreover, also in this setting an hematological improvement can occur in a sizeable rate of patients.

Disclosures:
No relevant conflicts of interest to declare.
T-Cell Engineering For “off-The-shelf” Adoptive Immunotherapy
Authors: Poirot Laurent , Schiffer-Mannioui Cécile , Philip Brian , Derniame Sophie , Gouble Agnes , Chion-Sotinel Isabelle , Le Clerre Diane , Lemaire Laetitia , Grosse Stéphanie , Cheung Gordon , Arnould Sylvain , Smith Julianne , Pule Martin , Scharenberg Andrew 
Published: October 2019

Abstract
Adoptive T-cell therapies, where exogenous expression of a chimeric antigen receptor (CAR) confers cancer recognition, have shown significant promise in initial clinical trials. However, present adoptive immunotherapy Methods are limited by the need for manipulation of autologous patient T-cells. To permit such an approach in an allogeneic context, Transcription Activator-Like Effector Nucleases (TALENTM) have been used to simultaneously inactivate the endogenous T cell receptor and CD52, a cellular target for a lymphodepleting treatment. This approach reduces the risk of GVHD while permitting proliferation and activity of the introduced T lymphocytes in the presence of the immunosuppressive drug alemtuzumab. Electroporation of primary T cells with mRNA coding for the appropriate TALENTM result in double knock-out (dKO) frequencies of up to 70%. Furthermore, functional characterization demonstrates that the dKO cells are resistant to complement dependent lysis or in vivo depletion by alemtuzumab, and show no apparent potential for TCR-mediated activation. Finally, endowing the dKO cells with a CD19 CAR supports their capacity to kill CD19+ tumor targets as efficiently as unedited T-cells both in vitro and in vivo.

Disclosures:
Poirot: CELLECTIS THERAPEUTICS: Employment. Schiffer-Mannioui:CELLECTIS THERAPEUTICS: Employment. Philip:UCL Cancer Institute, London, United Kingdom: Employment. Derniame:CELLECTIS THERAPEUTICS: Employment. Gouble:CELLECTIS THERAPEUTICS: Employment. Chion-Sotinel:CELLECTIS THERAPEUTICS: Employment. Le Clerre:CELLECTIS THERAPEUTICS: Employment. Lemaire:CELLECTIS THERAPEUTICS: Employment. Grosse:CELLECTIS THERAPEUTICS: Employment. Cheung:UCL Cancer Institute, London, United Kingdom: Employment. Arnould:CELLECTIS THERAPEUTICS: Employment. Smith:CELLECTIS THERAPEUTICS: Employment. Pule:UCL Cancer Institute, London, United Kingdom: Employment. Scharenberg:CELLECTIS THERAPEUTICS: Employment.
The Pan-PIM Kinase Inhibitor LGH447 Shows Activity In PIM2-Dependent Multiple Myeloma and In AML Models
Authors: Garcia Pablo D , Langowski John L , Holash Jocelyn , Burger Matthew , Zang Richard , Zavorotinskaya Tatiana , Fanton Christie , Saci Abdel , Growney Joseph , Vanasse K. Gary 
Published: October 2019

Abstract

Background
PIM1, PIM2, and PIM3 are a closely related family of constitutively active serine/threonine kinases. PIM kinases were first identified as common integration sites in MMLV-induced murine T-cell lymphomas, with these viral insertions resulting in transcriptional activation and expression of the kinase. Similar unbiased insertional mutagenesis screens were used to demonstrate that the three kinases could substitute for each other in this oncogenic process, indicating that inhibition of all three PIM kinases may be necessary to achieve a therapeutic benefit. In human cancers, increased expression and activity of PIM kinases has been detected in many hematopoietic malignancies and solid tumors (prostate, lung, liver) and it is thought that this contributes to cancer cell survival and proliferation in these malignancies.

Methods & Results
We have developed a potent and specific pan-PIM inhibitor, LGH447, and shown that it is active in PIM2-dependent Multiple Myeloma (MM) cell lines by inhibiting proliferation, mTOR-C1 signaling and phosphorylation of BAD. In addition, LGH447 inhibited proliferation of several AML cell lines. Furthermore, we demonstrated that LGH447 inhibits tumor growth in several mouse subcutaneous xenograft models of MM and AML, where modulation of the pharmacodynamic marker phospho-S6 Ribosomal Protein was used to predict efficacy. We have also determined that LGH447 significantly reduced the bone tumor burden in a disseminated orthotopic human xenograft model of MM. Finally, we have demonstrated increased activity of LGH447 in combination with the PI3K inhibitor BYL719 in a MM model and with Cytarabine in an AML model.

Summary
Our Results have supported the clinical development of LGH447, a Pan-PIM inhibitor, in relapsed, refractory MM, and further suggest that it may be effective in the treatment of AML and other hematological malignancies, either as a single agent or in combination with other select therapeutic agents.

Disclosures:
Garcia: Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Langowski:Novartis Institutes for Biomedical Research: Employment. Holash:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Burger:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Zang:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Zavorotinskaya:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Fanton:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Saci:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Growney:Novartis Institutes for Biomedical Research: Employment, Equity Ownership. Vanasse:Novartis Pharmaceuticals Corporation: Employment.