bluuebunny/crossref_metadata_2025_split huggingface dataset:
PML-RARα Repressed Microrna 126 Mediates Differentiation in Acute Promyelocytic Leukemia By Targeting the Protooncogene C-Myb
Authors: Schödel Cindy , Hartmann Jens-Uwe , Gerloff Dennis , Braeuer-Hartmann Daniela , Katzerke Christiane , Wurm Alexander Arthur , Müller-Tidow Carsten , Tenen Daniel G. , Niederwieser Dietger , Behre Gerhard 
Published: November 2019

Abstract
Almost one tenth of acute myeloid leukemias (AML) are related to t(15;17) translocation. This aberration leads to the PML-RARα fusion protein, which causes a transcriptional block of differentiation and could be resolved by all-trans-retinoic acid (ATRA). MicroRNAs (miRs) are small noncoding RNAs which are ascribed to be important regulators of cell proliferation, development, differentiation and apoptosis. MiR-126 is regarded as tumor suppressor in diverse tissues, but relatively little is known about its functional role in normal and malignant hematopoiesis. In this report, we reveal that oncogenic PML-RARα fusion protein is a repressor of miR-126 expression. Thus, we could demonstrate a significant downregulation of miR-126 expression in presence of the PML-RARα fusion protein in APL versus other AML patient samples and in a PML-RARα Knock in mouse model. We further show that ATRA induced differentiation of APL cell line NB4 comes along with an increase of miR-126 expression. The transient overexpression of miR-126 enhances ATRA stimulated differentiation of myeloid cells, whereas the opposite effect was noticed when endogenous expression of miR-126 was knocked down. Most interestingly, we observed a significant upregulation of miR-126 expression in APL blasts during ATRA treatment of APL patients. C-Myb proto-oncogene was found to be a putative target of miR-126 by analysing the 3’UTR. We could show a reduced c-Myb protein level after enforced expression of miR-126. Further, we reveal that miR-126 leads to a posttransciptional downregulation of c-Myb expression by directly targeting its 3`UTR. Our data suggest miR-126 as an important regulator of differentiation in acute promyelocytic leukemia, targeting the proto-oncogene c-Myb and recommend microRNAs to be potential therapeutic agents.

Disclosures
No relevant conflicts of interest to declare.
A Novel Suppressive Long Noncoding RNA within the IGF1R Gene Locus Is Imprinted in Acute Myelocytic Leukemia
Authors: Sun Jingnan , Hu Jifan , Li Wei , SUN Yunpeng 
Published: November 2019

Abstract
Background：In acute myeloid leukemia (AML) cells, the insulin-like growth factor type I receptor (IGF1R) is one of the most abundantly phosphorylated receptor tyrosine kinases, promoting cell growth and therapeutic resistance through the PI3K/Akt signaling pathway. However, little is known regarding the molecular mechanisms underlying IGF1R gene dysregulation in AML. Long non-coding RNAs have been implicated in a variety of important biological processes by epigenetic mechanisms.
Materials and methods：AML cell lines used in this study, KG-1, KG-1a were purchased from ATCC. The full length of IRAIN lncRNA was characterized by Marathon cDNA Amplification Kit. For qPCR, cDNA samples were amplified using CFX96TM real-time system (BIO-RAD) by SYBR PrimeScript™ RT-PCR Kit (TaKaRa). Both reverse transcription-associated trap (RAT) and chromatin conformation capture (3C) assays were used to examine the chromosome architecture of IGF1R and DNA-RNA interaction. The protocol of AMLpatients bone marrow and peripheral blood cell samples was approved by the Human Medical Ethical Review Committee from Jilin University First Hospital and informed consent was obtained from each AML patient and normal donor.
Results：
1. we discovered a novel intragenic 5366bp long noncoding RNA (lncRNA) within the IGF1R locus, named IRAIN, which is transcribed in an antisense direction from an intronic promoter.
2. we demonstrated IRAIN was expressed exclusively from the paternal allele, with the maternal counterpart being silenced in normal donor and AML patients.
3. we confirmed that IRAIN interacts with IGF1R chromatin DNA and is involved in the formation of an intrachromosomal enhancer/promoter loop. Knockdown of IRAIN lncRNA with shRNA abolishes this intrachromosomal interaction.
4. We demonstrated IRAIN was downregulated both in AML cell lines and high risk AML patients. Furthermore，the expression of IRAIN was dramatical higher in APL patients achieved molecular remission.
Conclusion：Our results identify IRAIN as a new imprinted suppressive lncRNA involved in long range IGF1R DNA interactions in AML. As a putative tumor suppressor and a novel treatment target， further studies are needed to delineate the specific role of this newly identified lncRNA in the uregulation of the IGF pathway in AML.

Disclosures
No relevant conflicts of interest to declare.
Differential Response of Fanconi Anemia Hematopoietic Stem and Progenitor Cells to Oxidative and Oncogenic Stresses
Authors: Du Wei , Amarachintha Surya , Ozlem Erden , Pang Qishen 
Published: November 2019

Abstract
Members of the Fanconi anemia (FA) protein family are involved in DNA damage response. A common damage to DNA in vivo is oxidative stress, and compelling evidence suggests that FA cells are in an in vivo pro-oxidant state. In response to oncogenic activation, normal cells induce genetically encoding programs that prevent deregulated proliferation and thus protect multicellular organisms from cancer progression. How FA cells respond to oxidative DNA damage and oncogenic stress is largely unknown. By employing an in vivo stress-response model expressing the Gadd45b-luciferase transgene, we show here that hematopoietic stem and progenitor cells (HSPCs) from mice deficient for the FA gene Fanca or Fancc differentially responded to oxidative and oncogenic stresses. Compared to wild-type controls, Fanca-/- or Fancc-/- HSPCs exhibited a persistent response to oxidative stress. Mechanistically, we demonstrated that accumulation of unrepaired DNA damage, particularly in oxidative damage-sensitive genes, was responsible for the long-lasting response in FA HSPCs. In contrast, using two inducible models of oncogenic activation (LSL-K-rasG12D and MycER), we identify a short-lived response of FA HSPCs to oncogenic insults both in vitro and in vivo. Mechanistic studies revealed that loss of Fanca or Fancc impaired oncogenic stress-induced senescence (OIS), and genetic correction of Fanca or Fancc deficiency restored OIS in HSPCs. Furthermore, FA deficiency compromised K-rasG12D-induced arginine methylation of p53 mediated by the protein arginine methyltransferase 5 (PRMT5). Finally, forced expression of PRMT5 in HSPCs from LSL-K-rasG12D/CreER-Fanca-/- mice prolonged oncogenic response and delayed leukemia development in recipient mice. Taken together, our study demonstrates differential responses of HSPCs to oxidative and oncogenic stresses and identifies the FA pathway as an integral part of this versatile cellular mechanism.

Disclosures
No relevant conflicts of interest to declare.
Activity of ABT-199 and Acquired Resistance in Follicular Lymphoma Cells
Authors: Bodo Juraj , Zhao Xiaoxian , Smith Mitchell R. , Hsi Eric D. 
Published: November 2019

Abstract
ABT-199, a platelet-sparing pro-apoptotic BH3 mimetic shows promise in the treatment of B-cell malignancy such as chronic lymphocytic leukemia (CLL). Given the central role of BCL2 expression in follicular lymphoma (FL), we studied the effects of ABT-199 on proliferation, induction of apoptosis, and signaling pathways in the t(14;18)+ FL cell lines WSU-FSCCL and FC-TxFL2 and in primary FL cells. We also developed an ABT-199-resistant FC-TxFL2 cell line by continuous treatment with ABT-199.
The growth of tested cell lines and primary FL cells was significantly inhibited with nanomolar concentrations of ABT-199. FC-TxFL2 cells (IC50 = 7 nM) were more sensitive to ABT-199 treatment than WSU-FSCCL cells (IC50 = 110 nM). The increased sensitivity was associated with higher levels of BIM pro-apoptotic protein. ABT-199 induced rapid phosphorylation of JNK kinase and substantial decrease of mitochondrial potential in FC-TxFL2 cells. Inhibition of JNK activation further augmented the apoptosis induced with ABT-199. All other tested anti-apoptotic (such as BCL-2, BCL-xL, MCL-1) and pro-apoptotic proteins (such as Bax, Puma, Bak, Bad, Noxa, Bid, Bok) were similarly expressed in both cell lines and did not change upon ABT-199 treatment. Surprisingly, cleavage of Bid was observed, which points also to activation of extrinsic apoptotic pathway. In cells with acquired resistance after continuous ABT-199 exposure, we identified increased levels of MCL-1, and elevated phosphorylation of BCL-2 on T56 and of AKT on S473, but also evidence for increased autophagy, as assessed by LC3BI/II expression, compared to parental cells. These cells remained resistant several weeks after omitting ABT-199 from culture medium.
In a FL murine xenograft model, ABT-199 showed anti-tumor activity. Treatment significantly decreased tumors volumes compared to untreated mice. Subsequently isolated xenograft FC-TxFL2 cells previously exposed to ABT-199 showed increased resistance to ABT-199. However, unlike in vitro exposed cells, the resistance quickly diminished after cultivation without ABT-199. Next, the ability to overcome ABT-199 resistance with epigenetic modifiers such as decitabine and vorinostat was tested. A strong synergistic effect in potentiation of apoptosis with these therapeutics was observed.
Despite the theoretic rationale for BH3 mimetic activity in FL, activity in patients with FL has not been as dramatic as has been observed for CLL. Relatively easily acquired resistance observed in our model may explain this failure. Therefore, combinations that can prevent resistance acquisition should be intensively studied and moved quickly to clinical trials.

Disclosures
Smith: Abbvie: Research Funding.
Reactive Oxygen Species Produced By Myeloid Cells Block CD20-Antibody Dependent NK Cell-Mediated Cytotoxicity Against Chronic Lymphocytic Leukemia Cells
Authors: Werlenius Olle , Aurelius Johan , Simpanen Maria , Riise Rebecca E , Akhiani Ali A , Martner Anna , Andersson Per-Ola , Hellstrand Kristoffer , Thorén Fredrik B 
Published: November 2019

Abstract
Introduction:
The addition of the anti-CD20 antibodies rituximab or ofatumumab to chemotherapy has improved the outcome for patients with chronic lymphocytic leukemia (CLL), but the efficacy of anti-CD20 monoclonal antibodies (mAbs) as single agents is limited. Immunosuppressive reactive oxygen species (ROS), produced by myeloid cells, including monocytes, may be a limiting factor for the efficacy of ADCC-dependent therapy. With the aim of reducing a potentially inhibitory role of ROS on mAb-dependent NK cell cytotoxicity against CLL cells, we performed in vitro cytotoxicity experiments in the presence of monocytes and the ROS formation inhibitor histamine dihydrochloride (HDC).
Methods:
After informed consent, blood samples were collected from Binet stage A CLL patients seen at Sahlgrenska University Hospital, Gothenburg, Sweden. NK cells, monocytes and CLL cells were isolated from PBMCs by immunomagnetic negative selection or flow cytometry. ROS production by monocytes was assessed by isoluminol-enhanced chemiluminescense upon stimulation with the chemotactic peptide fMLF in the presence or absence of CLL cells, rituximab (Roche), ofatumumab (GSK), HDC or the NADPH oxidase inhibitor DPI. NK cell death was assessed by flow cytometry after over-night culture of monocytes and lymphocytes. Autologous ADCC assays were performed with NK cells, monocytes and CFSE-labeled CLL cells in the presence or absence of rituximab, ofatumumab, HDC, catalase and interleukin-2 (IL-2). CLL cell death was determined by flow cytometry after live/dead staining. The study was approved by the local ethical review board of Gothenburg, and conducted in accordance with the declaration of Helsinki.
Results:
Rituximab and ofatumumab both triggered extracellular ROS production by monocytes. ROS production was blocked by the NADPH oxidase inhibitor DPI. Furthermore, monocytes induced ROS-dependent apoptosis in adjacent NK cells. In the cytotoxicity experiments, rituximab-mediated NK cell dependent cytotoxicity against CLL cells was significantly inhibited by the presence of autologous monocytes. This suppression, as well as the induction of NK cell apoptosis, were dependent on ROS, since both HDC and catalase significantly increased cytotoxicity and rescued NK cells from monocyte-induced apoptosis. Expectedly, IL-2 augmented NK cell-mediated ADCC.
Conclusion:
The results imply that CLL patients harbor immunosuppressive myeloid cells that reduce CD20-antibody dependent NK cell-mediated cytotoxicity against leukemic cells by producing ROS. We propose that treatment with HDC, preferably in conjunction with NK cell stimulatory cytokines, may improve anti-CD20-based immunotherapy in CLL.

Disclosures
No relevant conflicts of interest to declare.
Myeloid Dysfunction in Sickle Cell Disease
Authors: Romano Alessandra , Parrinello Nunziatina Laura , Conticello Concetta , Rosso Rossellina , Caterina Perrotta , Colletta Grazia , Ximenes Benedetta , La Cava Piera , Meli Carmela RITA , Di Raimondo Francesco 
Published: November 2019

Abstract
Background
In sickle cell disease (SCD), profound anaemia and severe hemosiderosis cause functional and physiological abnormalities in various organ systems, including immune system. Infectious complications are common, constitute the second most common cause of mortality and a main cause of morbidity. During the haemolytic crisis, large amount of arginase (s-Arg-1) are released, potentially acting as immunosuppressor molecule.
Despite its clinical impact, only a few is known about myeloid dysregulation in SCD.
Aim Detecting immunological impairment at the steady state evaluating myeloid and lymphoid cells in peripheral blood of SCD patients.
Material and Methods
Between May and June 2014,peripheral blood obtained from 30 consecutive SCD patients at the steady state plus 30 healthy subjects was studied for evaluation of myeloid subpopulations and lymphoid paresis.
Myeloiddys function was evaluated as percentage and absolute count of circulating myeloid suppressor cells (MDSC) in peripheral blood assessed by flow cytometry as follows: im-MDSC (CD34+/CD11b+/CD13+/CD14-/ HLA-DR-/CD45+), neutrophilic-like N-MDSC (CD11b+/CD13+/CD15+/CD14-/HLA-DR-/Lin-) and monocytic-likemo-MDSC (CD14+/HLA-DRlow/-), phagocytic activityof granulocytes using a commercially available kit (Phagotest R), amount of Arg-1 expressed in mature granulocytes by RT-PCR and circulating s-Arg-1 using a commercially available ELISA kit (Biovendor).
Results
The capability of phagocytosis of granulocytes wassignificantly reduced compared to healthy subjects (p=0.001). G-MDSC subset was not increased, while mo-MDSC subpopulation was increased in SCD (p=0.001) but not in thalasso-SCD.
s-ARG-1 was increased in both SCD and thalasso-SCD (respectively 203±3 ng/mL and 248±6ng/mL, p=0.003) and positively correlated with the amount of HbS (r=0.7, p=0.002). Arg-1 expression in granulocytes was increased (20 times higher than healthy controls, p=0.002)
Conclusion
SCD and thalasso-SCD caucasian patients exhibiti mmunosuppressive myeloid markers including reduced phagocytosis, increased amount of mo-MDSC, Arg-1 expression in granulocytes and circulating s-Arg-1. Further analysis are ongoing to detect if the same myeloid impairment occurs during vase occlusive crisis and in a different genetic background, like in Afro-Americans.

Disclosures
No relevant conflicts of interest to declare.
Clinical and Laboratory Evaluation of Patients with Familial Hemophagocytic Lymphohistiocytosis in a Single Center; Striking the Importance of Central Nervous System and Hepatic Involvement
Authors: Beken Burcin , Aytac Selin , Kuskonmaz Barýs , Balta Gunay , Cetin Mualla , Gurgey Aytemiz , Uckan Cetinkaya Duygu , Gumruk Fatma 
Published: November 2019

Abstract
Familial hemophagocytic lymphohistiocytosis (FHL) is an autosomal recessive, life-threatening condition characterized by deficient immune response. The major underlying defect in FHL is impaired Natural Killer (NK) cell and T lymphocyte degranulation and/or cytotoxicity, and the only curative treatment is hematopoetic stem cell transplantation (HSCT).
In this retrospective study, 57 patients who were diagnosed with FHL at Hacettepe University Ýhsan Dogramacý Children’s Hospital Pediatric Hematology Department, between November 1994 and December 2012 were evaluated for their clinical and laboratory findings, factors affecting the response to treatment, prognosis and survival.
Median age of these patient’s was 18 months (0.16-226 months). Mutation analysis were performed in 37 patients and of these, 11 had UNC13D, 10 had PRF1 and three had STX11 gene mutation. Fourty four persent of the patients had central nervous system (CNS) involvment on admission and spinal cord involvement was also seen on five patients. The median age of the patients who had spinal cord involvement was 11 years (7.5-14 years) and all of these have neurological symptoms, positive cerebrospinal fluid (CSF) and brain MRI findings related to FHL. One of the patients had spinal cord involvement on admission, the other four patients developed spinal cord involvement at follow up and all of these four patients were died despite HSCT.
Remission was achieved in 24 patients with the treatment protocols, HLH-1994 and HLH-2004, in a median time of 76 days (min-max:15-705 days). When factors affecting the remission time were evaluated, remission time was prolonged 3.1 times in patients with ferritin level ≥1500 mg/dL. The five year overall survival was 25% and HSCT was performed in 18 patients (32%) and five year survival rate was 44% in the transplant group.
When patients were grouped according to their ages [Group 1 (0-24 months) and Group 2 (>24 months)]; there were 33 patients below two years and 24 patients above two years. Patients in Group 1 had higher ferritin (p=0.001) and AST (p=0.043) levels whereas lower fibrinogen (p=0.023) levels on admission, survival rate was also lower in these patients (p=0.017). When we analyze the patients in Group 1, we found that patients with hepatic involment had poor prognosis (p=0.002).
In conclusion, FHL is a disease with high mortality rates and the only curative treatment is HSCT. When FHL is suspected, genetic studies should be done and not only CNS but also spinal cord imaging should be performed as well. Treatment must be started immediately in patients who has poor prognostic factors including, age below two years, ferritin level above 1500 mg/dL, and spinal cord, bone marrow or hepatic involvement.

Disclosures
No relevant conflicts of interest to declare.
Unusual Presentation for Unusual Infection: Disseminated Mycobacterium Avium-Intracellulare complex (MAC) in Patient with Sickle Cell Anemia Mimicking Blood Transfusion Reaction
Authors: Edrees Nayf , Howard Thomas H. 
Published: November 2019

Abstract
Nontuberculous mycobacteria (NTM) are ubiquitous free living soil and water– borne organisms that cause numerous clinical syndromes including lymphadenitis, skin, soft tissue and pulmonary infections, however disseminated infection is almost exclusively in patient with severe immunocompromise (i.e:HIV, Hematological malignancy, and bone marrow transplant).
Mycobacterium avium complex (MAC) is hard to diagnose as it is considered slow grower NTM.
We describe a case of disseminated Mycobacterium avium-intracellulare complex infection in teenager with sickle hemoglobinopathy with unique presentation mimicking pRBCs transfusion reaction.
Patient presented on three different occasions with tachycardia, hypotension and fever within 2-24 hours following pRBCs pheresis, all three episodes were investigated and were negative for transfusion reactions.
Patient had central venous catheter (CVC), frequent admissions for vaso-occlusive painful episode, on hydrocortisone for adrenal insufficiency and off Hydroxyurea for two months.
Diagnosis of mycobacterium avium complex bacteremia was confirmed by two positive blood cultures, whole body CT scan showed liver nodules, spleen nodules and lung nodules. Pulmonary dissemination was confirmed by Biopsy and culture, Lymphocyte markers showed severe lymphopenia with absolute CD4 count of 64.
Patient underwent treatment with three month of four antibiotics followed by 9 months of three antibiotics with removal of the central line, follow up scan showed decrease size and numbers of nodules, patient started tolerating pheresis within one month of the antibiotics initiation.
NTM infection should be added to the list of pathogens in sickle cell patients with CVCs and fever and should be considered in frequent pRBC transfusion like reaction with negative workup.
Routine blood culture can identify rapid growing NTM but specific mycobacterial blood culture is required in case of other NTM species (slow grower). As dissemination almost always occurs in those with impaired cellular immunity, HIV testing and lymphocyte markers should be performed
Removal of involved CVCs is essential for the treatment as well as appropriate antimicrobial medications.

Disclosures
No relevant conflicts of interest to declare.
A Novel Notch/NRF2 Mechanism Mediates Reductive Stress in Acute Myeloblastic Leukemia (AML): A Therapeutic Strategy to Overcome Chemoresistance
Authors: Kannan Sankaranarayanan , Zweidler-McKay Patrick A. 
Published: November 2019

Abstract
Background: Chronic oxidative stress (COS) is the consequence of prolonged elevation of reactive oxygen species (ROS). In the context of AML, COS leads to sustained induction of antioxidant pathways to compensate for COS. The presence of abundant antioxidants may contribute to chemoresistance in AML. NRF2 is a master regulator of the antioxidant response, is induced by oxidative stress and functions as a cyto-protective mechanism in acute oxidative stress. In AML, sustained NRF2-activation can be viewed as a pathological maladaptation as it leads to elevated reductive metabolite formation, termed reductive stress (RS). In this study we describe a novel link between NRF2-induced reductive stress and the Notch pathway in AML.
Approach: Redox balance was measured in AML patient samples in the setting of Notch activation (via DLL1 ligand) and/or NRF2 inhibition (via Brusatol).
Results: AML samples demonstrate increased reductive metabolites (i.e. reductive stress) compared to controls and Notch activation decreases aberrant reductive metabolite levels to control baseline (GSH/GSSG ratio, panel A). Mechanistically, Notch signaling induced increased ROS formation, decreased NRF2 protein levels, and decreased expression of multiple NRF2-responsive antioxidants (data not shown). Importantly, Notch activation also enhanced the efficacy of an NRF2 inhibitor Brusatol (from *P≤0.05 to **P≤0.01) in combination with ROS-producing chemotherapeutic doxorubicin, eradicating >98% of AML cells within 48 hours (** P≤0.01; panel B).
Conclusions: We describe the aberrant accumulation of reductive metabolites in human AML as a potential cytoprotective maladaptation, i.e. reductive stress. Furthermore, we demonstrate a novel mechanism whereby Notch activation regulates the antioxidant response via suppression of the master regulator NRF2. These data establish the pivotal role of Notch/NRF2 in the regulation of antioxidant responses in AML, which have potential clinical significance for ROS-inducing chemotherapies.
Figure 1. Figure 1.

Disclosures
No relevant conflicts of interest to declare.