bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of Lymphocyte Activation Gene 3 (LAG-3/CD223) by Chronic Lymphocytic Leukemia B Cells.
Authors: Chuang Han-Yu , Liu Yu-Tsueng , Rassenti Laura Z. , Huynh Lang , Carson Dennis , Kipps Thomas J. 
Published: April 2020

Abstract
The clinical course of chronic lymphocytic leukemia (CLL) is variable. DNA-microarray studies have shown that the gene-expression patterns of CLL cells with unmutated IgVH genes are similar to those of cells with mutated IgVH genes, but that the patterns of both are distinct from those of other leukemias and lymphomas. Nevertheless, the two subtypes of CLL can be distinguished by the differential expression of a small number of genes, one of which encodes ZAP-70, an intracellular tyrosine kinase with a critical role in T-cell receptor signaling. Further analysis of the mutation status of IgVH genes and ZAP-70 expression revealed that CLL patients with B cells expressing ZAP-70 and unmutated IgVH genes had a more aggressive disease. LAG-3 (CD223) is thought to play a role in immune responses mediated by T and NK cells. LAG-3, a CD4 homolog, is a ligand for MHC class II antigens. Similar to ZAP-70, LAG-3 is selectively expressed on activated T and NK cells and has recently been shown to be expressed on T-cell activated B cells. We compared the gene expression profiles of the B cells purified from 15 CLL patients using the Affymetrix HG-U133 plus 2.0. This analysis revealed LAG-3 and parathymosin differentially expressed at higher levels by the CLL cells expressing ZAP-70 and unmutated IgVH genes. LAG-3 and parathymosin are located on chromosome 12p13 with head-to-tail orientation. To examine for surface expression of LAG-3, we performed flow cytometry on these same 15 CLL samples using an anti LAG-3 mAb (CD223). We found LAG-3 expressed at high levels by the CD5/CD19 B cells of 4/8 (50%) cases that expressed ZAP-70 and unmutated IgVH genes. Conversely, the samples with B cells lacking ZAP-70 and with mutated IgVH genes did not express LAG-3 (0/7). All samples (15/15) expressed high level of MHC class II antigens, as assessed by flow cytometry. LAG-3 may interact with MHC class II molecules expressed by CLL cells to form an autocrine loop that may further enhance the activation of ZAP-70-expressing CLL B cells. Further analysis is needed to delineate the role of LAG-3 in the pathogenesis and/or progression of this disease.
Human Antagonistic Anti-CD40 Antibody, CHIR-12.12, Inhibits CD40-Mediated Survival of Chronic Lymphocytic Leukemia B Cells Leading to Cellular Apoptosis.
Authors: Cherukuri Anu , Kadel Edward , Lee Sang H. , Goldbeck Cheryl , Heise Carla , Luqman Mohammad , Aukerman Sharon L. , Aziz Natasha , O’Brien Susan , Wierda William G. , Jallal Bahija 
Published: April 2020

Abstract
CD40 and CD40 ligand (CD40L) interaction is a key regulator of B-chronic lymphocytic leukemia (CLL) survival. CD40 activation leads to binding with tumor necrosis factor receptor-associated factors (TRAFs) and the subsequent activation of multiple downstream signaling pathways involved in cellular proliferation and survival. We have generated a novel fully human IgG1 anti-CD40 antagonistic monoclonal antibody, CHIR-12.12, using XenoMouse® mice (Abgenix, Inc). CHIR-12.12 blocks CD40L binding to CD40 and inhibits CD40L-induced proliferation/survival of normal human B cells, primary CLL cells, and primary non-Hodgkin’s lymphoma (NHL) cells. We have also demonstrated that it has highly potent antibody-dependent cellular cytotoxicity (ADCC) against primary CLL and non-Hodgkin’s lymphoma cells. We have now investigated its effects on primary CLL cell survival. Soluble human CD40L prolongs primary CLL cell survival in culture, and treatment with CHIR-12.12 inhibits this survival when measured 48–72 hours after addition of CHIR-12.12. CD40L-mediated survival is associated with activation and phosphorylation of Akt, p38 MAPK, ERK, and IkB kinases a and b. Additionally, the anti-apoptotic proteins Mcl-1, Bcl-xl, and XIAP are induced, and markers of apoptosis (cleaved PARP and Caspase-3) are reduced. In contrast, CHIR-12.12 treatment of CD40L-stimulated primary CLL cells ex vivo inhibited downstream phosphorylation of Akt, p38 MAPK, ERK, and IkB kinases (IKK) a and b. Additionally, CHIR-12.12 treatment resulted in induction of cleaved caspase-3 and PARP, and reduction of XIAP, Mcl-1, and Bcl-xl expression, ultimately leading to CLL cell apoptosis. These results demonstrate that CHIR-12.12 inhibits CD40L-mediated signaling pathways and cell survival and could be a potential therapeutic treatment for CLL. CHIR-12.12 is currently in a Phase I clinical study for CLL.
The Shaving Reaction. Rituximab/CD20 Complexes Are Removed from Mantle Cell Lymphoma Cells (Z138) and Chronic Lymphocytic Leukemia (CLL) Cells by Monocyte/Macrophages: In Vitro Studies and a SCID Mouse Model.
Authors: Taylor Ronald P. , Beum Paul V. , Li Yongli , Lindorfer Margaret A. , Williams Michael E. 
Published: April 2020

Abstract
Clinical investigations have revealed that infusion of immunotherapeutic monoclonal antibodies directed to normal or tumor cells can lead to loss of targeted epitopes, a phenomenon called antigenic modulation. Recently we reported that Rituximab (RTX) treatment of CLL patients induced substantial loss of CD20 on B cells found in the circulation after RTX infusion, when RTX plasma concentrations were high. Antigenic modulation can severely compromise therapeutic efficacy, and we postulated that B cells had been “shaved” of RTX/CD20 complexes by monocytes or macrophages of the mononuclear phagocytic system (MPS) in a reaction mediated by Fcγ receptors. Our in vitro model is based on reacting RTX-opsonized CD20+ cells with acceptor THP-1 monocytes differentiated to a macrophage-like phenotype. After 45 min at 37°C, ~50–80% of both RTX and CD20 are removed from opsonized cells, and both proteins are demonstrable on acceptor THP-1 cells, as ascertained by flow cytometry, fluorescence microscopy, and immunoblotting. Tests with inhibitors and use of F(ab’)2 fragments of RTX indicate shaving is mediated by Fcγ receptors, and shaving occurs equally well in the presence and absence of complement. We developed a pre-clinical xenograft mouse model to replicate shaving: 5 X 106 Z138 cells were infused iv or sc, into SCID/CB17 mice, and ~25 days later animals were treated with varying doses of RTX. Z138 cells recovered from lungs (iv model) or tumors (sc model) of treated and control mice 30 min to 3 days after RTX infusion were analyzed by flow cytometry. Substantial loss of CD20 was demonstrable on RTX-targeted cells, and this loss was more pronounced at longer times after RTX infusion. Moreover, Z138 cells in untreated mice had moderate to high levels of CD20 and few cell-associated C3 fragments, but in RTX-treated mice the situation was reversed: the Z138 cells were CD20 poor (&lt;20% of the CD20 levels compared to untreated mice) but had significant amounts of deposited C3dg. These findings replicate our earlier studies which demonstrated that treatment of CLL patients with RTX promotes loss of CD20 as well as complement activation and C3 fragment deposition on circulating B cells. It is likely that previously described antigenic modulation, usually reported for conditions of high circulating malignant cell burdens targeted by monoclonal antibodies, was also mediated by cells of the MPS via the shaving reaction. Our findings may have profound implications for the use of monoclonal antibodies in the immunotherapy of cancer.
Pilot Study of Thrice-Weekly Low-Dose Rituximab (RTX) in Chronic Lymphocytic Leukemia (CLL): Decreased CD20 Loss Via “Shaving” and a Novel Strategy for Enhanced Therapeutic Targeting.
Authors: Williams Michael E. , Densmore John J. , Pawluczkowycz Andrew W. , Beum Paul V. , Kennedy Adam D. , Lindorfer Margaret A. , Hamil Susan H. , Petroni Gina R. , Eggleton Jane C. , Taylor Ronald P. 
Published: April 2020

Abstract
Treatment of CLL patients with RTX 375 mg/m2 induces 90% loss of CD20 from circulating cells via “shaving” of RTX-CD20 complexes from B cells, presumably by tissue macrophages (Kennedy, et al, J Immunol, 2004). To reduce CD20 loss and potentially enhance leukemic cell clearance, we investigated frequent low-dose RTX for CLL. Following informed consent, patients were treated 3 times/wk with RTX 20 or 60 mg/m2 x 2 wks (1 pt) or 4 wks (11 pts) with frequent blood sampling during and post-RTX. 9/12 were previously treated (1–4 prior therapies); only 2 had received prior RTX. Cytogenetics by FISH analysis: del 17p13 (6 pts), del 13q14 (5 pts) and trisomy 12 (1 pt).
Results: In each initial infusion, the first 30 mg of RTX caused a 3 to &gt;10-fold decrease in leukemic cells in 11/12 patients. 60 mg/m2group (n=6): Two hrs after the 1st RTX infusion, cells expressed &lt;20% of baseline CD20 levels; these levels further decreased with subsequent RTX treatments. 2/6 achieved normal lymphocyte counts. One patient achieved CR, ongoing at 9+ mo.; 5 had stable adenopathy and/or splenomegaly (SD) for 3–8 mo.; 3 required subsequent therapy. 20 mg/m2group (n=6): Two hrs after the 1st RTX infusion, cell surface CD20 levels were at ≥50% of initial values (4/6 pts) and were preserved throughout RTX therapy in 5/6 patients. 3/6 achieved normal lymphocyte counts with subsequent RTX infusions. One patient achieved CR lasting 8 mo. There was 1 PR, 3 SD and 1 with no response; 4 required subsequent therapy. The 2 patients with highest cell surface CD20 expression achieved CR, despite the presence of the del 17p13 in both cases. RTX infusion activated Complement (C); large amounts of the C3 activation product C3dg were deposited on targeted cells. However, 70% of deposited C3dg was demonstrable on circulating cells which had lost CD20 and persisted in the circulation.
Toxicity: Treatments were well tolerated, with grade 1–2 infusion reactions and transient neutropenia and thrombocytopenia during initial infusions.
Conclusions: Thrice-weekly low-dose RTX is clinically active and can induce remissions in patients with CLL. Low-dose RTX may promote enhanced cytotoxic attack and clearance of circulating CLL cells via CD20 target preservation; 20 mg/m2 dosing better preserves CD20 levels via decreased shaving vs 60 mg/m2. Our findings suggest that C3dg can serve as a molecular marker for circulating CLL cells which have lost CD20 due to shaving during RTX therapy. These results support further investigation of thrice-weekly low-dose RTX as a novel strategy for improved therapeutic targeting of RTX in CLL.
A Phase 2 Clinical Trial of AP23573, an mTOR Inhibitor, in Patients with Relapsed or Refractory Hematologic Malignancies.
Authors: Rizzieri David A. , Feldman Eric , Moore Joseph O. , Roboz Gail J. , DiPersio John F. , Gabrail Nashat , Stock Wendy , Rivera Victor M. , Albitar Maher , Bedrosian Camille L. , Giles Francis 
Published: April 2020

Abstract
Background: AP23573 is a novel non-prodrug rapamycin analog that inhibits mTOR, a downstream effector of the PI3K/Akt and nutrient-sensing pathways. In phase I clinical trials, AP23573 completely inhibited in vivo mTOR activity in peripheral blood mononuclear cells (PBMCs) as measured by decreased phosphorylation of the mTOR target protein 4E-BP1. Because the mTOR pathway has been implicated in the pathobiology of hematologic malignancies, this study is undertaken in this patient population to determine the safety and efficacy of AP23573 treatment. In addition, correlative studies in PBMC and bone marrow samples will examine if tumoral mTOR pathway status predicts clinical response.
Methods: Eligible patients with relapsed or refractory hematologic malignancies are being enrolled, stratified into 5 disease specific groups and given AP23573 12.5 mg I.V. daily x 5 days (QDx5) every 2 weeks. Enrollment into each group is proceeding according to a Simon’s two-stage design with a minimum of 21 patients per group and an overall maximum enrollment of 205. Efficacy is being assessed according to standard response criteria at the end of each 4-week cycle (leukemia patients) or every two cycles (lymphoma patients). In addition, pharmacodynamic (PD)/biomarker samples for correlative studies are collected during Cycle 1.
Results: At this time, a total of 51 patients have been enrolled. There are 35 males and 16 females with a median age of 61 years (range 31–83). Best or most recent response to treatment by disease cohort is shown below (5 are too early for response evaluation).
Disease Cohort (N) PR HI SD PD PR: Partial Response, HI: Hematologic Improvement, SD: Stable Disease, PD: Progressive Disease Cohort 1: AML/MDS (26) 2 6 18 Cohort 2: ALL (2) 2 Cohort 3: AMM (7) 2 3 2 Cohort 4: CLL (9) 4 3 Cohort 5: T-cell Lymphoma (2), MCL (5) 2 2
AP23573 is generally well tolerated with the most prevalent mild or moderate treatment-related adverse events (AEs) being nausea, mucositis, hyponatremia, pruritis, rash, and hypokalemia. Serious, possibly treatment-related AEs include diarrhea, mucositis, hypertriglyceridemia, neutropenic sepsis, dyspnea, syncope, pleural effusion and pneumonia. Analysis of correlative PD/biomarker studies is in progress.
Conclusions: QDx5, every other week administration of AP23573 has an acceptable side-effect profile with potential efficacy in some patients with advanced stage hematologic malignancies. Indications of anti-cancer activity have been observed in 4 of the 5 disease cohorts with 19 of the 46 evaluable patients (41%) showing at least stable disease. Patient enrollment, treatment and correlative biomarker analyses continue.
The Novel Anti-Leukemic Agent LC-1, Is Preferentially Cytotoxic in CLL Cells Derived from Poor Prognostic Subsets.
Authors: Pepper Chris , Fegan Chris , Brennan Paul , Mills Ken , Burnett Alan K. 
Published: April 2020

Abstract
Chronic lymphocytic leukemia (CLL) has a variable clinical course but once treatment is required the development of drug resistance often ensues. Therefore, delineation of the biological mechanisms of drug resistance and the development of novel therapies designed to overcome this is an important goal of research into this condition. We have recently shown that the transcription factor NF-κB plays a central role in regulating CLL cell survival and this is mediated, at least in part, through the transactivation of a number of anti-apoptotic genes including Bcl-2. In this pre-clinical study we evaluated the cytotoxic effects of the novel parthenolide analog, LC-1 (Leuchemix Inc.), in primary tumor cells derived from 49 CLL patients (20 treated, 29 untreated). LC-1 induced apoptosis, as assessed by the Annexin V assay, in a concentration-dependent manner (0.1 – 10 μM) in all the CLL samples tested with a mean LD50 value (the concentration of drug required to kill 50% of the cells) of 2.9 μM. The induction of apoptosis was preceded by a marked loss of NF-κB activity, as evidenced by electrophoretic mobility shift assay, and a down regulation in Bcl-2 protein expression. Caspase-3 activation was a consistent feature of LC-1-induced apoptosis pointing to the involvement of the intrinsic apoptotic pathway. Importantly, CD38+ samples (&gt; 30% expression) and those derived from patients with unmutated VH genes were more sensitive to LC-1 (LD50 values = 2.3 μM versus 3.4 μM and 2.4 μM versus 3.2 μM; P = 0.0003 and 0.01 respectively) suggesting that these CLL cells have a disproportionate reliance on NF-κB activity to maintain their survival and proliferative advantage. Taken together our data clearly demonstrates that LC-1 preferentially targets CLL cells from poor prognostic subsets. This unique cytotoxicity profile warrants further investigation and supports the use of this agent in early clinical trials for patients with CLL.
Reconstitution of the T Cell Repertoire Following Treatment with Alemtuzumab in Patients with B-Cell Chronic Lymphocytic Leukemia (B-CLL).
Authors: Rezvany Mohammad R. , Tehrani Mahmood J. , Karlsson Claes , Lundin Jeanette , Rabbani Hodjattallah , Mellstedt Håkan , Österborg Anders 
Published: April 2020

Abstract
Background and Methods: B-cell chronic lymphocytic leukemia (B-CLL) occurs as a result of clonal accumulation of functionally abnormal B cells. Alemtuzumab is a humanized monoclonal antibody specific for the CD52 antigen, which is highly expressed on both B-CLL cells and normal lymphocytes, but not on hematopoietic (CD34) stem cells. Alemtuzumab has been shown to effectively deplete the blood and bone marrow of lymphocytes, including CD4 and CD8 T cells, which may lead to profound immunosuppression and make patients more susceptible to infections. We and others have previously shown that the CD4 T cells in B-CLL patients may be clonally distinct from the normal population in that they present a more clonal pattern of the T-cell receptor (TCR) repertoire (Rezvany et al, Blood2003;101:1063–1070). It is therefore of interest to study the T cell repertoire following alemtuzumab administration as well as factors affecting T cell reconstitution following CD52 targeted therapy. In this study, we evaluated in depth the T-cell receptor-beta-variable sequence (TCR BV) in CD4 and CD8 T cells by real-time PCR, before and repeatedly after/during long term follow-up, in 5 B-CLL patients who had received alemtuzumab as first-line therapy (Lundin et al, Blood2002;100:768–773). Also, an analysis was conducted of CDR3 length polymorphism to describe changes in the clonality pattern.
Results: A decline in most of BV genes either in CD4 or CD8 T cells was observed shortly after alemtuzumab treatment, which was followed by a gradual increase in most of the BV genes during long-term follow up. CDR3 length polymorphism analysis shortly after treatment revealed an even more highly restricted pattern in CD4 T cells compared to baseline with a shift towards a monoclonal/oligoclonal pattern regardless of increased or decreased BV usage. Furthermore, in the analysis of the clonal spectrum that was expressed shortly after alemtuzumab therapy, the number of peaks was significantly reduced in CD4 (P &lt;0.01) but not in CD8 T cells, which was followed by a gradual increase in diversity towards a polyclonal repertoire during long-term follow up.
Conclusions: These results indicate that perturbations in the T cell repertoire following alemtuzumab are complex, and are not reflected by changes in CD4/CD8 T cell numbers only. The restricted CDR3 pattern present prior to therapy became even more restricted after end of treatment, followed by a normalization of CDR3 patterns in CD4 T-cells during long-term follow-up. These results further suggest a regulatory role for T cells in relation to the malignant B cell clone in patients with B-CLL.
Pivotal Role of Survivin in Leukemogenesis by E2A-HLF Chimeric Transcription Factor.
Authors: Okuya Mayuko , Kurosawa Hidemitsu , Matsunaga Takayuki , Eguchi Mitsuoki , Furukawa Yusuke , Inukai Takeshi , Matsui Hirotaka , Look A. Thomas , Inaba Toshiya 
Published: April 2020

Abstract
The E2A-HLF fusion transcription factor generated by the t(17;19)(q22;p13) translocation is found in a small population of pro-B cell ALL. Patients associated with this chimera share distinct clinical features such as hypercalcemia, coagulopathy and very poor prognosis due to resistance to intensive chemotherapy including aggressive conditioning for BMT, all of which are unusual for this type of ALL. We have previously demonstrated that inhibition of the trans-activation potential of the E2A-HLF chimera by the dominant negative mutant results in apoptosis in t(17;19)+ ALL cells but does not affect cell cycle. Moreover, E2A-HLF blocks apoptosis induced by cytokine deprivation in IL-3-dependent cells, suggesting that this fusion protein contributes to leukemogenesis by substituting for the anti-apoptotic function of cytokines. The present study shows that survivin is a downstream target molecule of E2A-HLF. Four t(17;19)+ ALL cell lines expressed survivin at high levels and down-regulation of E2A-HLF function by the dominant negative mutant suppressed survivin expression. In addition, forced expression of E2A-HLF in Nalm-6, a t(17;19)− ALL cell line, up-regulated survivin expression. Survivin is known to be expressed predominantly in the G2/M phase. Indeed, separation of the fractions enriched for in each phase of the cell cycle using a counterflow centrifugal elutriator revealed G2/M phase-dominant survivin expression in t(17;19) − ALL cells including Nalm-6. In t(17;19)+ ALL cells, however, survivin was expressed throughout the cell cycle. Moreover, Nalm-6 cells forced to express E2A-HLF showed cell cycle-independent survivin expression. Reporter assay revealed that E2A-HLF induced luciferase activity by transfecting with each reporter construct containing the survivin promoter at a different length from the initial ATG, suggesting that E2A-HLF induces survivin expression at the transcriptional level, but not by direct binding of E2A-HLF to the survivin promoter. To test whether survivin plays anti-apoptotic roles in t(17:19)+ cells, we used a survivin mutant lacking a phosphorylation site (T34A-survivin) and considered to inhibit survivin function in a dominant negative manner. T34A-survivin induced massive apoptosis throughout the cell cycle in t(17;19)+ cells. In contrast, T34A-survivin in t(17;19) − cells induced cell death in only a small population in G2/M phase. In addition to caspase-dependent pathways, T34A-survivin induced apoptosis in t(17;19)+ ALL cells through caspase-independent pathways, in which apoptosis-inducing factor (AIF) translocated from cytoplasm to the nucleus. These results indicate that cell cycle-independent up-regulation of survivin by the E2A-HLF chimera is indispensable for the survival of t(17;19)+ ALL cells, and that inhibition of survivin may offer an effective therapeutic strategy against this refractory ALL.