bluuebunny/crossref_metadata_2025_split huggingface dataset:
Anti-CD20 Antibody GA101 in Combination with Chemotherapy or Flavopiridol in Mantle Cell Lymphoma.
Authors: Heinrich Daniel A. , Klein Christian , Decheva Kristina , Weinkauf Marc , Hutter Grit , Zimmermann Yvonne , Weiglein Tobias , Hiddemann Wolfgang , Dreyling Martin H. 
Published: October 2019

Abstract
Abstract 4781

Background
Mantle cell lymphoma (MCL) responds only transiently to conventional chemotherapy resulting in a dismal long-term prognosis. At a molecular level it is characterised by the chromosomal translocation t(11;14)(q13;q32), which leads to constitutive over-expression of the cell cycle regulatory protein cyclin D1. GA101 is a third generation, glycoengineered type II IgG1 anti-CD20 monoclonal antibody with superior direct cell death induction by targeting a type II epitope and enhanced antibody dependent cellular cytotoxicity (ADCC). High efficacy in lymphoma cell lines has led to combination experiments with various chemotherapeutic compounds or the CDK-inhibitor Flavopiridol.

Methods
Using a MCL cell line panel (Granta-519, HBL-2, Jeko-1, Rec-1 and Z-138) and a Diffuse Large B-Cell Lymphoma cell line (Karpas-422) we determined the effect of GA101 (1 μg/ml) monotherapy as well as in combination with Fludarabine (0,25 μg/ml), Bendamustine (5 μg/ml), Mitoxantrone (0,25 and 0,5 μg/ml) and Flavopiridol (100nM) on cell proliferation and viability. Trypan-blue exclusion tests were used to analyze cell viability at 0h, 24h, 48h and 72h. The panel of MCL cell lines was treated to determine potential synergism of agent combinations. Accordingly, fractional product was calculated: synergism > 0,1; additive effect -0,1<x<0,1; antagonism < -0,1.

Results
After mono-exposure with GA101 (1 μg/ml), Granta-519 and Rec-1 showed the highest sensitivity (Granta: 65-75% cell reduction, Rec-1: 30-45%). Intermediate results were achieved for HBL-2 (20-30%), Z-138 and Karpas-422 (10-15%), Jeko-1 (5%). Fludarabine alone resulted in a 20-40% cell reduction. Bendamustine showed a higher efficacy in Jeko-1, Rec-1 and Z-138 (40-90%) than in Granta-519, Karpas-422 and HBL-2 (10%). Mitoxantrone treatment demonstrated a high impact on all cell lines (80-95% cell reduction). Flavopiridol induced a 65-85% cell reduction in Jeko-1, Rec-1 and Karpas-422in comparison to 30-45% in Granta-519, HBL-2 and Z-138. Additional experiments showed additive effects of all GA101 combinations resulting in 40-80% cell reduction (Fludarabine), 30-90% (Bendamustine), 85-95% (Mitoxantrone) and 60-80% (Flavopiridol).

Conclusions
These in vitro results demonstrate that the anti-CD20 monoclonal antibody GA101 alone or in combination with various chemotherapeutical compounds or the CDK-inhibitor (Flavopiridol) show a promising efficacy in MCL cell lines (additive in combination), supporting the clinical evaluation of such an innovative immuno-chemotherapy in mantle cell lymphoma.

Disclosures:
Klein: Roche (Glycart): Employment, Equity Ownership, Patents & Royalties. Weinkauf:Lilly Deutschland GmbH: Research Funding. Hutter:Lilly Deutschland GmbH: Research Funding. Zimmermann:Lilly Deutschland GmbH: Research Funding. Dreyling:Roche: Honoraria, Research Funding.
Protein Tomography Analysis Shows That CD20 Molecules Bound by Different Type I and Type II Anti-CD20 Antibodies Are Organized in Different Protein Complexes.
Authors: Niederfellner Gerhard J , Braennstroem Annika , Lindstrom Frida , Jansson Magnus , Lundin Marika , Schaefer Wolfgang , Mundigl Olaf , Umana Pablo , Klein Christian 
Published: October 2019

Abstract
Abstract 4782
Ramos cells were labeled with Type I (Rituximab and Ocrelizumab) and Type II (B1/H299 and GA101) anti-CD20 antibodies and then fixed and stained with marker gold labeled 2ary antibodies. Protein complexes connected to marker gold were analyzed by Protein TomographyTM at SIDEC and the corresponding 3D-structures visualized (∼100 structures per antibody). Less than 5 % of the refined structures were dimeric. While most (60 – 90%) CD20 molecules were present in tetramers or even higher order defined complexes, a sizeable proportion was also engaged in large protein networks (11 -38%). For the multimeric complexes, we could clearly distinguish between extended (or open) and ring-like (or closed) conformations. Although cells had been labeled with an excess of antibody, as suggested by FACS binding curves, the antibodies bound CD20 monovalently in most refined structures. Bivalent binding was overall more prevalent with Rituximab and Ocrelizumab than with B1 and GA101 (1/3 vs 1/6 structures). The proportion of CD20 molecules present in ringlike complexes was higher for the Type II than for the Type I antibodies. In co-localization experiments, Rituximab-CD20 and GA101-CD20 complexes were also found to only partially colocalize, while a large fraction of the two antibodies were found in separate cell surface compartments. These findings suggest that the different antibodies favor different CD20 conformations that seem to be associated with different protein complexes and might form the basis for initiation of different downstream signaling processes.

Disclosures:
Niederfellner: Roche: Employment. Braennstroem:SIDEC: Employment. Lindstrom:SIDEC: Employment. Jansson:SIDEC: Employment. Lundin:SIDEC: Employment. Schaefer:Roche: Employment. Mundigl:Roche: Employment. Umana:Glycart: Employment, Equity Ownership, Patents & Royalties. Klein:Roche: Employment, Equity Ownership, Patents & Royalties.
Cholesterol Regulation and Statin Therapy in Patients with Waldenstrom's Macroglobulinemia.
Authors: Ioakimidis Thea , Patterson Christopher J , Hunter Zachary , Soumerai Jacob , Manning Robert , Warren Diane L. , Ghobrial Irene , Sheehy Patricia , Treon Steven 
Published: October 2019

Abstract
Abstract 4789
Patients with WM commonly display low cholesterol levels, particularly LDL and VLDL levels. Given these observations, we examined their levels in 110 patients with WM, and observed decreased total cholesterol (<160 mg/dL), LDL (<100 mg/dL) and VLDL (<40 mg/dL) levels in 41 (37.3%), 68 (61.8%) and 90 (81.8%) patients, respectively. Importantly, median serum IgM levels which serve as a surrogate marker for WM disease burden were higher among patients with hypocholesterolemia (3440 vs. 1587 mg/dL; p=0.0004). Longitudinal follow-up of progressing as well as responding patients demonstrated an inverse correlation between serum IgM and cholesterol levels, which was not an artifact of laboratory testing. Importantly, significantly lower serum IgM levels (885 vs. 1960 mg/dL; p=0.004) were observed among those patients who were on a statin lipid-lowering agent. We therefore investigated the in vitro potential of statins to mediate anti-WM activity and showed that simvastatin acted a potent inducer of WM cell apoptosis through inhibition of geranylgeranylated proteins. Given these observations, we investigated the potential of simvastatin to suppress disease progression in WM patients with slowly progressing disease who would otherwise have been on watch and wait.

Patients and Methods
Eighteen patients, 8 of whom were previously untreated, and who were asymptomatic with slowly progressing disease were enrolled in this study. The median age for these patients was 67 (range 42-88 years), median IgM was 2,610 (571-5,880 mg/dL), and median hematocrit was 35.4 (range 30.2-41.4%). Patients received Simvastatin at 20 mg daily for the first week, then dose escalated weekly by 20 mg a day to a maximum of 80 mg daily by week 4. Patients were maintained on therapy until progression.

Results
With a median follow-up of 6 months (range 3-18 months), 7 patients have demonstrated objective disease progression. No objective responses have been observed in any treated patients. Among non-progressing patients, serum IgM levels (2,610 vs. 2545 mg/dL) and hematocrit (35.4% vs. 34.5%) remain stable (p=NS). Grade 2 toxicities included elevation in CPK (n=1), and musculoskeletal pain (n=3). No grade 3 toxicities were observed.

Conclusions
Simvastatin does not produce objective responses in patients with WM, though may have potential for suppression of disease progression in some patients with WM.

Disclosures:
No relevant conflicts of interest to declare.
ESAP-Lenalidomide - a Highly Active Regimen in Refractory or Relapsed Hodgkin's Lymphoma.
Authors: Tempescul Adrian , Ianotto Jean-Christophe , Guillerm Gaelle , Berthou Christian 
Published: October 2019

Abstract
Abstract 4797
Hodgkin's disease (HD) is a commonly cured lymphoma. Unfortunately between 10 and 20% of patients are refractory or relapse after a first line of treatment. There is evidence that for these patients the best approach is salvage chemotherapy followed by high-dose chemotherapy (HDC) and autologous stem cell transplantation (ASCT). Existing salvage regimens of chemotherapy, mainly based on platines or aracytine, have a response rate between 60-85%. Usually is associated a toxicity resulting in delay of chemotherapy or dose reduction. It is very important to achieve complete remission before HDC/ABSCT.
It has been proved that 18-FDG PET has a predictive value on Hodgkin's lymphoma.
Into the pathophysiology of HD are implicated various cytokines like IL6, IL12, IL13, NFkB and angiogenic factors. Immunomodulatory drugs have an impact on microenvironment, altering cytokine secretion and the expression of adhesion molecules which can result in apoptosis of malignant B-cell.
Lenalidomide, having both immunomodulatory and antiangiogenic activity, proved to be highly active into the treatment of myeloma and some forms of non-Hodgkin's lymphoma. Into a phase two studies, Lenalidomide administrated as a single agent, proves to be also active into the refractory or relapsed Hodgkin's lymphoma.
During a period of one year, we identified eight patients with refractory ore relapsed HD. We have treated these patients with classical salvage chemotherapy regimen – ESAP- in which we associated Lenalidomide, administrated continuously during the whole period of treatment. We evaluate the response by 18-FDG PET, early, after two or three cycles of ESAP-Lenalidomide association. We obtained seven complete remissions and one very good partial remission (minimal residual disease in PET SCAN). The toxicity was essentially hematological, neutropenia and trombocytopenia.
This small study proves that Lenalidomide, a new drug with both immunomodulatory and antiangiogenic effects, associated to a classical salvage regimen of chemotherapy is highly active on refractory or relapsing Hodgkin's lymphoma.

Disclosures:
No relevant conflicts of interest to declare.
The Plant-Derived Agent α-Bisabolol Induces Apoptosis of Leukemic Blasts Ex Vivo.
Authors: Bonifacio Massimiliano , Cavalieri Elisabetta , Rigo Antonella , de Prati Alessandra Carcereri , Pizzolo Giovanni , Vinante Fabrizio , Suzuki Hisanori 
Published: October 2019

Abstract
Abstract 4800

Introduction
α-bisabolol is a small, oily, non-toxic sesquiterpene alcohol that in rats crosses easily the hemato-encephalic barrier, accumulating in brain without substantial neurotoxicity. We have previously demonstated that α-bisabolol exerts strong cytotoxic effect on a number of malignant human and rat cell lines entering cells via lipid-rafts. This makes α-bisabolol a candidate molecule for anti-cancer therapy.

Materials and methods
We tested ex vivo 42 acute leukemias of lymphoid (ALL) or myeloid (AML) lineage (14 Ph-ALL, 14 Ph+ALL, 14 AML) in a 24-hour dose-response sensitivity assay to α-bisabolol (30, 60 125, 250 μM). Viable cells from freshly heparinized peripheral blood or bone marrow of healthy subjects were used as control.

Results
Low-dose α-bisabolol was highly cytotoxic against primary Ph-ALL (IC50=50±23 μM). Also Ph+ALL, including Ph+-cells resistant to imatinib mesylate, and AML cells were effectively killed (IC50=70±17 and 83±12 μM, respectively). Cytotoxicity on normal haematologic cells increased in a dose- and time-dependent manner: 60, 125, and 250 μM α-bisabolol was not cytotoxic, cytotoxic over 24, and cytotoxic over 5 hours, respectively. Normal bone marrow counterpart was less sensitive to α-bisabolol (IC50=145±11 and 95±14 μM, for CD33+ myeloid and CD34+ cells, respectively). To study the mechanism of α-bisabolol-induced apoptosis, we evaluated at single cell level the mitochondrial transmembrane potential (ΔΨm) through the lipophilic cationic fluorochrome JC-1, by comparison between leukemias and a negative control (T-lymphocytes). Microscopy observation revealed that in untreated leukemic cells, well-polarized mitochondria were marked by punctate red fluorescent staining superimposed over diffuse green fluorescence; after 3-hour incubation with 60 μM α-bisabolol this pattern was almost completely replaced by diffuse green fluorescence, thus indicating the ΔΨm disruption and then the starting of the apoptotic process. Flow cytometric analysis confirmed the same phenomenon. By contrast, normal T-lymphocytes, used as negative control, did not suffer any change in their microscopy or cytofluorimetric pattern when exposed to similar α-bisabolol concentration, and stayed vital.

Conclusions
α-bisabolol, acting via dissipation of the mitochondrial membrane potential, is an effective pro-apoptotic agent for primary leukemic cells ex vivo and could be considered as a possible candidate for treatment of both lymphocytic and myeloid acute leukemias. Interestingly, the majority of leukemias have a IC50 lower than that of their putative normal counterpart, represented by CD34+ cells.

Disclosures:
No relevant conflicts of interest to declare.
GRP-78 Secreted by Tumor Cells Blocks the Anti-Angiogenic Activity of Bortezomib.
Authors: Kern Johann , Untergasser Gerold , Zenzmaier Christoph , Sarg Bettina , Gastl Gunther , Gunsilius Eberhard , Steurer Michael 
Published: October 2019

Abstract
Abstract 4805
Anti-angiogenic effects of the proteasome inhibitor bortezomib were analyzed on tumor xenografts in vivo. Bortezomib strongly inhibited angiogenesis and vascularization in the chicken chorioallantoic membrane (CAM). Bortezomib's inhibitory effects on CAM vascularization were abrogated in the presence of distinct tumor xenografts thanks to a soluble factor secreted by tumor cells. Through size-exclusion and ion-exchange chromatography as well as mass spectroscopy we identified GRP-78, a chaperone protein of the unfolded protein response, as being responsible for bortezomib resistance. In fact, a variety of bortezomib-resistant solid tumor cell lines (PC-3, HRT-18), but not myeloma cell lines (U266, OPM-2), were able to secrete high amounts of GRP-78. Recombinant GRP-78 conferred bortezomib resistance to endothelial cells and OPM-2 myeloma cells. Knockdown of GRP78 gene expression in tumor cells and immunodepletion of GRP78 protein from tumor cell supernatants restored bortezomib sensitivity. GRP-78 did not bind or complex bortezomib, but induced prosurvival signals by phosphorylation of ERK and inhibited p53-mediated expression of pro-apoptotic Bok and Noxa proteins in endothelial cells.
From our data we conclude that distinct solid tumor cells are able to secrete GRP-78 into the tumor microenvironment, thus demonstrating a hitherto unknown mechanism of resistance to bortezomib.

Disclosures:
No relevant conflicts of interest to declare.
Synergistic Anti-Cancer Effects of Arsenic Trioxide and Paclitaxel On Human Malignant Lymphocytes.
Authors: Wu Ying-Li , Duan Xu-Fang , Xu Han-Zhang , Chen Guo-Qiang 
Published: October 2019

Abstract
Abstract 4809
Arsenic trioxide (ATO), an effective drug in the treatment of acute promyelocytic leukemia (APL), and its combination with other chemotherapeutic drugs have been shown to present some activities in other malignant cells besides APL. Increasing reports showed that ATO produces mitotic arrest possibly through targeting to tubulins before apoptosis induction in human tumor cells. Aberrations in the control of cell cycle progression occur in the majority of human malignancies; hence, tubulins are promising targets for anticancer therapy. Here, we define the cellular effects with ATO, alone or in association with paclitaxel, the first identified microtubules stabilizing agent, with respect to inhibition of cell proliferation and cell cycle progression and induction of apoptosis in malignant lymphocytic cell lines Jurkat, Raji, and NAMALWA as well as fresh acute lymphocytic leukemic (ALL) cells. Our results showed that the co-treatment of ATO and PTX at their lower concentrations could significantly induce mitotic arrest followed by growth inhibition and apoptosis in these cell lines. The combined treatment of ATO with PTX also synergistically decreased the cell viability in primary ALL cells. In vivo and in vitro experiments showed that the combination treatment did not increase the microtubules polymerization compared to ATO or PTX treatment alone. Instead, this synergistic action was attributed to the increase of phosphorylation of cyclin-dependent kinase 1 (Cdk1) on Thr161 and the promotion of the dysregulated activation of Cdk1. Furthermore, we found that the ATO/PTX combination significantly enhanced the activation of spindle checkpoint by inducing the formation of the inhibitory checkpoint complex BubR1/Cdc20. These results provide a rational basis for clinical trials of the combined regimen of ATO and PTX in the treatment of lymphocytic neoplasm.

Disclosures:
No relevant conflicts of interest to declare.
The Tyrosine Kinase Inhibitor Dasatinib Enhances Glucocorticoid-Induced Apoptosis and Sensitizes Chronic Lymphocytic Leukemia Cells to Dexamethasone.
Authors: Harr Michael W , Caimi Paolo F. , McColl Karen , Zhong Fei , Patel Shilen N , Barr Paul , Distelhorst Clark W. 
Published: October 2019

Abstract
Abstract 4811
Glucocorticoid hormones are frequently used as part of front-line therapy to treat lymphoid neoplasms. However, relative to acute lymphoblastic leukemia and many types of B cell lymphoma, chronic lymphocytic leukemia (CLL) cells are intrinsically resistant to glucocorticoids and the mechanism governing this resistance has not been fully investigated. Here we report that that the Src inhibitor dasatinib enhances glucocorticoid-induced apoptosis in lymphoid cells and sensitizes primary CLL cells to dexamethasone. This finding evolved from the observation that the Src kinase Lck was downregulated by dexamethasone in glucocorticoid sensitive T cells in order to suppress immunoreceptor activation and signaling. In contrast, aberrantly expressed Lck was not downregulated by dexamethasone in CLL cells. However, inhibition of Lck phosphorylation by dasatinib significantly enhanced cell killing to nanomolar concentrations of dexamethasone. Collectively, these data indicate that dasatinib sensitizes primary CLL cells to glucocorticoids, and thus, the combination of these agents may have therapeutic efficacy in patients with aggressive or refractory CLL.

Disclosures:
No relevant conflicts of interest to declare.
Identification of Target Molecules and Anti-Leukemic Effects of Novel Phospha Sugar Derivative, TMPP.
Authors: Nakamura Satoki , Yamashita Mitsuji , Takemura Tomonari , Yokota Daisuke , Hirano Isao , Ono Takaaki , Shigeno Kazuyuki , Shibata Kiyoshi , Fujie Michio , Fujisawa Shinya , Shinjo Kaori , Ohnishi Kazunori 
Published: October 2019

Abstract
Abstract 4814

Background and Aims
We synthesized two phospha sugar derivatives, 2,3,4-tribromo-3-methyl-1-phenylphospholane 1-oxide (TMPP) by reacting 3-methyl-1-phenyl-2-phospholene 1-oxide with bromine, and we has reported their potential as an antileukemic agent in cell lines. In this study, we have investigated that TMPP have antileukemic effects as shown in various leukemia cell lines as well as primary AML patient specimens. Moreover, we have identified the target molecules of TMPP by using docking simulation.

Methods
In human leukemia cell lines (HL60, NB4, U937, NOMO-1, CEM, MOLT4, SUP-B15, and YRK2 cells), the anti-leukemic effects were elevated by cell proliferation assay, Cell cycle analysis, Western blotting. In AML cells derived from AML patients and normal hematopoietic progenitor cells derived from healthy volunteers, the changes of viability by treatment with TMPP were evaluated. By using docking simulation, the target molecules were identified in leukemia cells treated with TMPP.

Results
TMPP showed inhibitory effects on leukemia cell proliferation, with mean IC50 values of 10.2 nmol/L for TMPP, indicating that inhibition appeared to be dependent on the number of bromine atoms in the structure. Further, TMPP at 8.4 nmol/L induced G2/M cell cycle block in leukemia cells, and TMPP at 17.3 nmol/L induced apoptosis in these cells. TMPP treatment reduced cell cycle progression signals (FoxM1, KIS, Cdc25B, Cyclin D1, Cyclin A, and Aurora-B) and tumor cell survival (Bcl-2, p27Kip1 and p21Cip1). Further, treatment with TMPP significantly reduced the viability of AML specimens derived from AML patients, but only slightly reduced the viability of normal ALDHhi progenitor cells. We also found that TMPP showed the strong activity against Aurora kinase B and Bcl-2 by using docking simulation.

Conclusion
We demonstrate that TMPP inhibits Aurora kinase B and Bcl-2 and shows a dominant Aurora B kinase inhibition-related cell cycle arrest and the induction of mitochondrial potential catastrophe-related apoptosis in acute leukemia cells. Moreover, we identified Aurora kinase B and Bcl-2 as the target molecules of TMPP. We conclude that TMPP has great therapeutic potential in anticancer therapy in a wide range of cancers.

Disclosures:
No relevant conflicts of interest to declare.
Effect of PDMP, a Glucosylceramide Synthase Inhibitor, On Resistance to Daunorubicin in Human Leukemia Cell Line K562/A02.
Authors: Chen Bao-An , Yin Li , Cheng Jian , Ding Jia-hua , Gao Chong , Zhao Gang , Wang Jun , Xia Guo-hua , Chen Ning-Na , Pei Xiao-Ping 
Published: October 2019

Abstract
Abstract 4821

Objective
Previous studies showed inhibition of glucosylceramide synthase (GCS) increased sensitivity to doxorubicin toxicity in multidrug-resistant cancer cells. This study was purposed to investigate the reversal effect of D, L-threo-1-phenyl-2- -decanoylamino-3-morpholino-1-propanol (PDMP), a glucosylceramide synthase inhibitor, on daunorubicin (DNR) resistance in K562/A02 cells.

Material and methods
The cytotoxicity and reversal effect were analyzed by MTT method. Flow cytometry was used to test DNR accumulation and apoptosis percentage. The expressions of GCS and mdr1 genes of K562 and K562/A02 cells were measured by RT-PCR and Western blot.

Results
The inhibition rates of PDMP (≤20μmol/l) on the proliferation of K562 and K562/A02 cells were below 10%. The IC50 of DNR for K562 and K562/A02 cells were 0.23±0.02μg/ml and 7.15±0.24μg/ml, respectively. PDMP increased sensitivity of K562/A02 cells to DNR toxicity in a dose-dependent manner (the IC50 was decreased to 2.76±0.25μg/ml by 20μM PDMP and to 4.23±0.08μg/ml by 10μM PDMP), but it had no effect on K562 cells. Both 10μM and 20μM PDMP increased DNR induced apoptosis compared with DNR alone (the apoptosis percentage were 8.93%±0.83%, 18.33% ± 0.86%and 5.43% ± 0.70% respectively). The mean fluorescence intensity of DNR in K562/A02 cells increased from 1550 treated by DNR alone to 1631 incubating with 10μM PDMP and higher to 1998 by 20μM PDMP. The expression of GCS gene was down-regulated by 20μM PDMP and blocking GCS also showed a dramatic decrease in mdr1 expression.

Conclusion
PDMP can increase the sensitivity to DNR toxicity in K562/A02 cells by enhancing cell apoptosis rate, intracellular DNR concentration, and down-regulating expressions of both GCS and mdr1 genes.

Disclosures:
No relevant conflicts of interest to declare.