bluuebunny/crossref_metadata_2025_split huggingface dataset:
Direct Inhibition of Fas Activation by CD74.
Authors: Berkova Zuzana , Garcia Michael , Wang Shu , Wise Jillian Frances , Tao Rong-Hua , Daniluk Urszula , Samaniego Felipe 
Published: October 2019

Abstract
Abstract 3770
Poster Board III-706
Hematopoietic cancers are commonly resistant to Fas-mediated apoptosis that contributes to their resistance to chemotherapy and reversing Fas resistance has become a primary interest in treating chemotherapy-resistant hematopoietic cancers. Wide expression of Fas receptor yet the limited extent of Fas-mediated apoptosis in tissues suggest a strict regulation of Fas signaling. A recently identified tissue-specific modulator of Fas-mediated apoptosis is hepatocyte growth factor (HGF) receptor HGFR/Met. HGFR/Met binds Fas and inhibits Fas signaling at an immediate early step. However, upon binding of ligand HGF to HGFR/Met, Fas is released and Fas signaling is restored. We hypothesized that hematopoietic cancers may express similar inhibitors of Fas, that can be targeted to resensitize cancer cells to Fas and thus also to therapy. We screen lymphoma cells for for such inhibitors. B cell lymphoma-derived BJAB cells and primary patient samples were incubated with Fas agonistic antibody. Upon removal of antibody excess, cell lysates were immuno-depleted of CH-11 antibody-bound and thus activated Fas. The remaining supernatant was then precipitated a second time with anti-Fas antibody B-10 that binds to the intracellular region of Fas. Protein bands present in B-10 precipitates and absent in CH-11 precipitates were excised from silver-stained gel and analyzed by mass-spectroscopy. CD74, also termed the invariant chain of MHC II and known to mediate pro-survival signaling as a receptor for macrophage migration inhibitory factor (MIF), was found to exclusively associate with activation-resistant Fas. Intriguingly, CD74 is known to be overexpressed in 80% to 95% of hematopoietic cancers and also in some solid tumors.
Using RNA interference we showed that CD74 negative cells are more sensitive to Fas-mediated apoptosis and that CD74 overexpression confers resistance to Fas both in vitro and in mouse tissues. Incubation of cells with peptides or anti-CD74 antibody LL1 disrupts the CD74-Fas inhibitory complex and sensitizes CD74-positive cells to Fas-mediated apoptosis. Analysis at the molecular level revealed that CD74 interferes with the immediate early steps in Fas signaling – binding of agonistic CH-11 antibody and subsequent clustering of Fas receptor.
We anticipate that specific disruption of the CD74-Fas interaction by CD74-derived peptides or anti-CD74 antibodies will sensitize cancer cells to Fas-mediated apoptosis. This approach represents a novel strategy for modulation of cell surface death receptors to produce effective treatments for CD74-positive cancers.

Disclosures:
No relevant conflicts of interest to declare.
Discovery and Validation of a Novel Class of Small Molecule Inhibitors of the CDC7 Kinase: Modulation of Tumor Cell Growth in Vitro and In Vivo.
Authors: Frattini Mark G. , Shum David , O'Dwyer Kristen M , Brentjens Renier J. , Maslak Peter , Heaney Mark , Jurcic Joseph G , Djaballah Hakim , Kelly Thomas J 
Published: October 2019

Abstract
Abstract 3771
Poster Board III-707
High throughput screening of compounds comprising the Memorial Sloan Kettering chemical library resulted in several confirmed hits against the recombinant Cdc7:Dbf4 heterodimeric kinase, a key regulator in the initiation of DNA replication and the G1 to S phase transition. Chemoinformatic analysis of the hits revealed an enrichment in one chemical cluster made up of several naturally occurring compounds, of which the most potent compound, CKI-7, was selected for further investigation. First, CKI-7 was found to be a non competitive inhibitor for ATP and prompted us to prolife it against a panel of 200 known kinases in order to assess its selectivity profile. The results were as predicted and very few kinases were specifically affected. Second, CKI-7 cytotoxic activity was assessed against a panel of well established cancer cell lines representing both hematopoietic and solid tumor malignancies as well as against a panel of primary hematopoietic cells derived from leukemia patients (both chemotherapy naïve and relapsed/refractory samples) and was found to be a very effective agent with potencies in the low nanomolar range. Subsequent studies using an isogenic pair of cell lines with one over expressing the Bcl_xL anti-apoptotic protein further confirmed the induction of the intrinsic apoptotic pathway via caspase-3 activation in the absence and attenuation of the activity in the presence of Bcl_xL. This was further demonstrated through standard cell cycle synchronization studies revealing that exposure to the Cdc7 inhibitor results in an S phase arrest, cell cycle dependent caspase-3 activation, and apoptotic cell death. This cell death is the direct result of Cdc7 kinase inhibition by CKI-7 as demonstrated using a Cdc7 substrate biomarker assay. Third, the physicochemical properties of this class of naturally occurring compounds also prompted us to investigate their effect on several multidrug resistence (MDR) over-expressing cell lines. We found that CKI-7 was not a substrate for the efflux pumps demonstrating that this novel compound can overcome a major mechanism of chemotherapy resistence in human tumor cells. Based of the above observations, in vivo dose-dependent anti-tumor activity of CKI-7 was subsequently demonstrated in a SCID-Beige mouse systemic tumor model utilizing a recently isolated Philadelphia chromosome positive acute lymphoblastic leukemia cell line (PhALL3.1). Taken together, our data confirm that Cdc7 is a new promising target for cancer therapy, and that the newly discovered inhibitor CKI-7, a naturally occurring selective small molecule inhibitor of this enzyme, is an equally promising novel cancer therapeutic agent.

Disclosures:
No relevant conflicts of interest to declare.
Pharmacological Inhibition of Fatty Acid Oxidation as a Novel Therapeutic Concept for Acute Myeloid Leukemia.
Authors: Andreeff Michael , Fiegl Michael , Konopleva Marina , Korchin Borys , Kaluarachchi Kumar , Bornmann William G. , Guthrie Patrick H. , Harmancey Romain , Taegtmeyer Heinrich , Samudio Ismael J. 
Published: October 2019

Abstract
Abstract 3779
Poster Board III-715
Otto Warburg proposed that the origin of cancer cells was closely linked to a permanent respiratory defect that bypassed the Pasteur effect, i.e. the inhibition of anaerobic fermentation by oxygen. We have recently demonstrated in leukemia cells that mitochondrial uncoupling, i.e. the abrogation of ATP synthesis in response to mitochondrial membrane potential (MMP), promotes the Warburg effect, contributes to chemo-resistance and represents a metabolic shift to fatty acid oxidation (FAO). Exposure of leukemic cells to marrow-derived mesenchymal stromal cells (MSC) promotes accumulation of lactate and reduces MMP. Stroma/leukemia co-cultures protect leukemia cells from chemotherapy-induced apoptosis. We found that he decrease in MMP was mediated by mitochondrial uncoupling accompanied by increased expression of mitochondrial uncoupling protein (UCP2) (Cancer Res. 68:5198,2008). We therefore proposed that the Warburg effect may be the result of preferential oxidation of fatty acids in cancer cell mitochondria (Cancer Res.69:2163,2009). Here we demonstrate that leukemia cells uncouple FAO from ATP synthesis, and that pharmacological inhibition of FAO with etomoxir or ranolazine inhibits proliferation and sensitizes leukemia cells – cultured alone or on bone marrow stromal cells – to apoptosis induction by the BH3 mimetic ABT-737 and the MDM-2 antagonist Nutlin 3a. Results suggest that leukemia cells rely, at least in part, on de novo fatty acid synthesis (FAS) to support FAO. Furthermore, treatment with the FAS inhibitor orlistat sensitized leukemia cells to apoptosis induction by ABT-737. Mechanistically, mitochondria derived from etomoxir treated leukemia cells were sensitized to release of cytochrome C and apoptosis-inducing-factor (AIF) upon treatment with ABT-737. Etomoxir (EX) facilitated the formation of Bak oligomers after treatment with ABT-737 suggesting that FAO regulates the activity of Bak-dependent mitochondrial permeability transition. Lastly, we present evidence that EX, in combination with liposomal ABT-737 or cytosine arabinoside (AraC), provides significant therapeutic benefit in a murine model of human leukemia (luciferase/GFP marked MOLT13 cells) as evidenced by reduced in vivo growth kinetics (BLI) and prolonged median survival (ABT-737 vs. EX+ABT-737, p=<0.05; AraC vs.EX+AraC,p<0.0001 ). Conclusions: 1) results support the notion that the Warburg effect may be the result of preferential oxidation of fatty acids by leukemia mitochondria. 2) Inhibition of fatty acid oxidation is proposed as a novel therapeutic concept for hematological malignancies.

Disclosures:
No relevant conflicts of interest to declare.
Engineering VSV-IFN-NIS for the Treatment of Multiple Myeloma.
Authors: Naik Shruthi , Nace Rebecca A. , Hadac Elizabeth A. , Dingli David , Federspiel Mark , Barber Glen N. , Russell Stephen J. 
Published: October 2019

Abstract
Abstract 378
The need for new and more effective long-term treatments for Multiple Myeloma (MM) has led to the utilization and engineering of replication competent (oncolytic) viruses as potential therapies. Vesicular stomatitis virus (VSV) is a potent oncolytic agent with several features that make it a favorable choice as a potential myeloma therapy. Specifically, (i) VSV replicates rapidly and can be grown to high titers (for effective clinical use) (ii) VSV undergoes transcription and replication exclusively in the cytoplasm avoiding host genome integration (iii) there is low/absent pre-existing immunity against VSV among the general population, (iv) naturally occurring human VSV infections are generally asymptomatic or result in minimal flu-like symptoms, (v) VSV is not easily transmitted between individuals (natural transmission is by hematophagous insects). Previously we showed weak oncolytic efficacy with an attenuated strain of VSV coding for the sodium iodide symporter (NIS) gene, VSV-D51-NIS, in the immune competent 5TGM1 syngeneic MM mouse model (C57Bl/KalwRijHsd) (Goel at. al. Blood. 2007 Oct 1;110(7):2342-50). Since VSV replication is strongly inhibited by IFN-induced innate immune responses in normal cells, but not in myeloma cells and IFN has known anti-myeloma activity, we hypothesized that the IFN-coding VSVs would be safer and more potent than previously tested VSV recombinants. We therefore constructed and tested the efficacy of VSVs coding for b-Interferon (VSV-IFN) or b-IFN and NIS (VSV-IFN-NIS). Interestingly, all of the newly constructed viruses, including VSV-IFN-NIS, showed greatly superior replication kinetics compared to the previously reported VSV-D51-NIS virus. Furthermore, compared to VSV-D51-NIS, VSV-IFN-NIS vectors induced higher NIS expression in vitro. In vivo therapy studies showed that a single intravenous dose of each of the IFN-coding VSVs promoted tumor regression and significantly prolonged survival of immunocompetent mice bearing subcutaneous or orthotopic 5TGM1 myeloma tumors. Tc-99m imaging studies conducted in mice treated with VSV-IFN-NIS, showed tumor specific virus mediated NIS expression and radio-isotope uptake that increased concurrently with intratumoral viral spread. Most importantly, there was no evidence of neurotoxicity following treatment with the IFN-coding VSVs. These studies indicate that VSV-IFN-NIS has potential as a novel therapeutic agent for multiple myeloma that can be combined with radio-isotopes for both non-invasive imaging of viral biodistribution and radiovirotherapy. A phase I clinical study is currently planned.

Disclosures:
No relevant conflicts of interest to declare.
Azacitidine Is Effective in Patients with Low / Intermediate-1 Risk Myelodysplastic Syndrome Managed in Community Based Practice: Preliminary Data From the Spanish Compassionate Use Registry.
Authors: Garcia Regina , de Miguel Dunia , Bernal Maria-Teresa , Tormo Mar , Sanz Guillermo , de Paz Raquel , Figueredo Antonio , Amutio Maria E , Guzmán José L. 
Published: October 2019

Abstract
Abstract 3801
Poster Board III-737

Background
Myelodysplastic syndrome (MDS) is comprised of a group of heterogeneous hematological disorders. Although the decision regarding treatment of a patient with MDS is based on performance status, age, patient preference and concomitant illnesses, NCCN-recommended treatment approaches vary according to IPSS risk score. Azacitidine (AZA) is a hypomethylating agent recently approved in Europe for the treatment of MDS. AZA was available in Spain under compassionate use before its regulatory approval and marketing authorization from the Spanish Medicines Agency in May 2009.

Material and Methods
We present the preliminary analysis of the clinical data from a longitudinal, multicenter Spanish patient registry. Data on the disease course and management of patients with MDS treated with AZA under compassionate use conditions were retrospectively collected from community-based hematology clinics. As of August 1, 2009, data from 90 patients MDS diagnosed according to WHO criteria had been collected with low / intermediate-1 International Prognostic Scoring System (IPSS) risk score.

Results
At baseline, the median age was 70 years, the male/female ratio was 69/31, and the majority of patients had primary MDS (80 patients; 90%) and an ECOG performance status of 0-1 (62 patients; 69%). The most frequent initial dose of AZA administered was 75 mg/m2 (77 patients, 86%). Almost all patients followed one of the following three schedules: days 1-7 (31%), days 1-5 and 8-9 (29%) or days 1-5 (37%) in a 28-day cycle. AZA was administered mostly subcutaneously (71 patients, 79%). The mean number of cycles administered was 7 (range 2-25). The overall treatment response was 61% (International Working Group 2006 criteria): 21% complete response, 11% complete bone marrow response, 3% partial response, 27% hematological response. In addition, 12% had stable disease. AZA was generally well tolerated. Grade 3/4 adverse events documented in these patients, regardless of their relationship to the active treatment, were neutropenia (48%), thrombocytopenia (36%), anemia (26%), febrile neutropenia (12%), rash (3%), injection site reaction (2%), asthenia (1%), septic shock (1%), constitutional symptoms (1%), and hypotension (1%).

Conclusion
These preliminary results demonstrate that, in a community-based setting, patients with low / intermediate-1 IPSS risk MDS respond to treatment with AZA, with an acceptable safety profile. More data derived from this registry and from the clinical trials are awaited.

Disclosures:
No relevant conflicts of interest to declare.
Efficacy of ICT with Deferasirox in Transfusional Iron Overloaded Patients with MDS or AA.
Authors: Cheong June-Won , Kim Hyeoung-Joon , Lee Kyoo-Hyung , Yoon Sung-Soo , Lee Jae Hoon , Park Hee-Sook , Kim Jin Seok , Kim Ho Young , Shim Hyeok , Seung Chu-Myung , Kim Chul Soo , Chung Jooseop , Hyun Myung Soo , Jo Deog-Yeon , Jung Chul Won , Sohn Sang Kyun , Yoon Hwi-Joong , Kim Byung Soo , Joo Young-Don , Park Chi-Young , Min Yoo-Hong 
Published: October 2019

Abstract
Abstract 3810
Poster Board III-746

PURPOSE
Transfusion-related iron overload and its consequences are emerging challenges in chronically transfused patients with myelodysplastic syndromes (MDS) or aplastic anemia (AA). The clinical data on specific benefits of deferasirox in transfusion-related iron overload patients with MDS or AA has been limited. METHODS: We have prospectively investigated the efficacy of deferasirox by serial measurement of s-ferritin level and LIC by R2-MRI in transfusional iron overload patients with MDS or AA. RESULTS: A total of 79 patients with de novo MDS (n = 29) or idiopathic AA (n = 50) showing serum ferritin level over 1,000ng/ml were enrolled from 23 institutes. Mean value of s-ferritin level in enrolled patients was 4,788 ng/ml in MDS and 4,188 ng/ml in AA at the time of deferasirox initiation. Mean value of LIC was 24.4 mg Fe/g dry weight in MDS and 22.4 mg Fe/g dry weight in AA. Deferasirox was given orally at a dose of 20 mg/kg/day for at least 6 months to all patients and was withheld If the s-ferritin falls below 500 ng/ml. Over the study period, patients with MDS or AA received a mean of 3.7 and 2.7 units RBC per month, respectively. After 12 months of medication, s-ferritin level significantly decreased by 1824.0 ng/ml form baseline values, a reduction of 38.1% for patients with MDS (p<0.0001) and significantly decreased by 3559.1 ng/ml (85.0%) for patients with AA (p<0.0001). LIC decreased by 11.2 mg Fe/g dry weight, a reduction of 35.7% for patients with MDS, and significantly decreased by 8.1 mg Fe/g dry weight, a reduction of 27.6% for patients with AA (p=0.0028). The patients with lower transfusional requirements (<4 units/month) during the study showed significantly more reduction of LIC level than those with higher requirements (≥4 units/month) (35.7% vs. 2.8%; p<0.0001). The most common drug-related adverse events (AE) were gastrointestinal disturbances and non-progressive increase in s-creatinine, however, AE were transient and mild-to-moderate in severity. All death was ascribed to disease-related causes including cytopenia in nine (11.4%) and disease progression in one (1.3%). CONCLUSION: Deferasirox is effective in reducing LIC and s-ferritin level in transfusional iron overload patients with MDS or AA, even with ongoing transfusion requirement, and well tolerated.

Disclosures:
No relevant conflicts of interest to declare.
Initial Evaluation of a 48-h Continuous Intravenous Infusion Weekly Regimen of ON 01910.Na in Advanced Myelodysplastic Syndrome (MDS).
Authors: Raza Azra , Galili Naomi , Ali Muhammad Shahzad , Ali Fahad , Goodman Alyssa , Qasim Samir Ahmed , Wilhelm Francois 
Published: October 2019

Abstract
Abstract 3815
Poster Board III-751
Following initial promising clinical results reported at ASH 2008 (Shenoy et al) in RAEB MDS and AML patients treated with the new investigational agent ON 01910.Na, we have initiated a phase 1/2 single arm escalating dose study in advanced MDS patients with a shorter schedule of administration of ON 01910.Na. The first 13 patients enrolled in our ongoing trial (6 high risk, 1 Intermediate-2 and 5 Intermediate-1 according to IPSS classification; 7 females/6 males, age range: 47-83ys), most of them having failed prior MDS therapies were administered ON 01910.Na as a 48 h continuous intravenous infusion weekly for 3 weeks of a 4-week cycle. Ten patients were treated at the 800 mg/m2/day dose level and 3 at the 1500 mg/m2/day dose level for 4 to 27+ weeks (1 to 6 four-week cycles). Most patients had grade 3 or 4 cytopenias at baseline. Overall the therapy was well tolerated and a few patients reported improvements of well being and pain relief. The most frequently reported adverse events were thrombocytopenia, neutropenia, anemia, fatigue and nausea. Serious adverse events were typical of this patient population and none of them was related to ON 01910.Na except for one case of neutropenia. Bone marrow blastic response was evaluated by bone marrow morphology. Five patients had a pretreatment blast count lower than 5% and no worsening of blast count was observed in the 3 patients who had follow-up bone marrow examination. Another six patients had more than 5% pretreatment bone marrow blasts. Among these patients, two had significant decreases in blast counts compared to pre-treatment values, while two showed stabilization and two progressed. Two patients had hematological improvements (neutrophil and erythroid responses). These results are encouraging and the trial is continuing.
Patient Bone Marrow Blasts Hematological Improvement Pre-Treatment 4-8 week Follow-up 1 <2% 2% 2 10-13% Death end 1st cycle 3 1-2% Not Done (Platelet =4) 4 20-30% 30% N wk 10-18 5 <5% 3% 6 3% Death end 2nd cycle 7 <5% 1-2% 8 25% 11% 9 10-13% 15%* E wk 1-13 10 35% Discontinued mid 2nd cycle (transplant) 11 9% 5% 12 10% 2% 13 15% 20% * 16 week Follow-up: 25% blasts

Disclosures:
Wilhelm: Onconova: Employment.
Lenalidomide Modulates the Phenotype and Function of Human Mesenchymal Stromal Cells From Healthy Donors and MDS Patients.
Authors: Wobus Manja , Dünnebier Gwendolin , Feldmann Silvia , Ehninger Gerhard , Bornhauser Martin , Platzbecker Uwe 
Published: October 2019

Abstract
Abstract 3816
Poster Board III-752

Introduction
Recent studies in patients with MDS have clearly demonstrated the clinical efficacy of lenalidomide. However, its exact mechanisms of action have not been elucidated yet. Myelosuppression is the most common adverse event and seems to be dependent on dose as well MDS subtype, being rather infrequent in patients other than del5q. The aim of this study was to investigate whether lenalidomide affects the bone marrow microenvironment. Therefore, we analyzed in-vitro characteristics of isolated mesenchymal stromal cells (MSCs) from MDS patients and from healthy controls.

Methods
Bone marrow samples were collected from healthy donors (n=5) and patients with MDS (del5q MDS n=3, RA n=2, RAEB1/2 n=3). MSCs were isolated according to the standard adhesion protocol and cultured in the presence or absence of lenalidomide.

Results
Lenalidomide treatment of MSCs caused no morphological changes but proliferation was slightly increased. Typical surface molecules as CD73, CD90, CD105 and CD166 were expressed in MSCs from MDS patients at comparable levels to healthy controls. Lenalidomide treatment caused an upregulation of CD29 by 17.8 ± 4.4% and of CD73 by 24 ± 5.7% (mean fluorescence intensity). Investigating the cytokine production, we found lower IL-8 mRNA and protein levels in MSCs from MDS patients (mean in MDS MSC: 138.1 pg/ml vs. mean in healthy MSC: 1177 pg/ml). Interestingly, the IL-8 production can be increased by approximately 40% under lenalidomide treatment. MDS MSCs retained the capacity for adipogenic and osteogenic differentiation as well as their supportive function towards hematopoietic cells in long term culture-initiating assays (LTC-IC). However, the LTC-IC frequency was lower on MSC which had been preincubated with lenalidomide compared to controls. Lenalidomide also slightly accelerated osteogenic differentiation because mineralization started as early as on day 5 with lenalidomide whereas in the control cells first calcium deposits were visible after 7 days. Other samples showed augmented lipid vacuoles after adipogenic differentiation under lenalidomide treatment.

Conclusion
In conclusion, lenalidomide modulates the phenotype of MSC and leads to an increase of their IL-8 secretion by a yet unknown mechanism. Whether these in-vitro effects are associated with the clinical efficacy of this compound in patients with MDS remains to be investigated.

Disclosures:
Platzbecker: Celgene: Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.