bluuebunny/crossref_metadata_2025_split huggingface dataset:
Expression of the Human Concentrative Nucleotide Transporter (hCNT1) Gene Correlates with Clinical Response in Patients Affected by Waldenstrom’s Macroglobulinemia (WM), Undergoing a Combination Treatment with Cladribine (2-CdA) and Rituximab.
Authors: Laszlo Daniele , Rabascio Cristina , Andreola Giovanna , Saronni Luca , Calabrese Liliana , Rigacci Luigi , Fabbri Alberto , Pinto Antonello , Frigeri Ferdinando , Billio Atto , Pinotti Graziella , Sammassimo Simona , Martinelli Giovanni 
Published: October 2019

Abstract
The aim of this prospective multicenter trial was to evaluate the efficacy of the nucleoside analogue 2-CdA in combination with Rituximab and to identify possible genetic factors that could influence the clinical response of the combination. From December 2003 to November 2006, 29 pretreated/newly diagnosed pts affected by WM were enrolled in the study. Pts characteristics included: sex (M/F) 9/19, median age 64 (range 36–75 yrs), a median IgM level before treatment of 2567mg/dL; 16 pts were newly diagnosed. The combination therapy was Rituximab at standard schedule (375 mg/mq) on day 1 followed by 2-CdA 0.1 mg/kg (sc injection) for 5 consecutive days. Each cycle was administered monthly for a total of 4 cycles. Clinical responses were evaluated two months after the end of treatment, according to Response Criteria from the 3rd International Workshop on WM. Expression analysis of the genes involved in the activity of 2-CdA (deoxycytidine kinase, deoxyguanosine kinase, 5′-nucleotidase, ribonucleotide reductase 1 and 2, human equilibrative nucleotide transporter and hCNT1) was performed on bone marrow cells, at baseline in 22 pts. The therapy was well tolerated, except in three patients who discontinued Rituximab due to cardiac toxicity during the first or second infusion. The treatment was delayed in 3 pts because of haematologic toxicity (G3 neutropenia) and in 2 of them the 2-CdA dose was reduced after 2 cycles. The only non-haematological complications observed were late respiratory infections which occurred in 3 pts. At a median follow-up of 21 (13–41) months we observed 17 (59%) CR/PR, 7 (24%) MR, 1 (3%) SD and 4 (14%) PD/NR. Pharmacogenomic analysis showed a statistically significant lower expression of the hCNT1 gene in pts who failed the treatment and who achieved a MR or SD than in those who achieved a CR or a PR (p=0.014) suggesting a possible relationship between reduced hCNT1 levels and a diminished clinical activity of 2-CdA. No significant difference was detected in the expression of the other genes analyzed. Our results suggest that the combination of 2-CDA and Rituximab is safe and active in WM pts; the use of pharmacogenomic analysis might contribute to a better selection of the patients who are more likely to respond to such a combination treatment.
Persistent Monoclonality after Histological Remission in Gastric Mucosa Associated Lymphoid Tissue (MALT) Lymphoma Treated with Chemotherapy and/or Surgery: Influence of t(11;18)(q21;q21).
Authors: Salar Antonio , Santon Almudena , Garcia-Cosio Monica , Bellosillo Beatriz , Rodriguez Patricia , Cristobal Eva , Serrano Sergio , Besses Carlos , Abraira Victor , Montalban Carlos 
Published: October 2019

Abstract
Background: The molecular response in patients with gastric MALT lymphoma achieving histological remission after chemotherapy with or without surgery is not well established.
Patients and Methods: 19 patients with gastric MALT lymphoma achieving complete histological remission after treatment with chemotherapy and/or surgery was studied retrospectively. IgVH gene rearrangements were studied by PCR in gastric biopsies obtained at diagnosis and during follow-up. Presence of t(11;18)(q21;q21) was studied by FISH or PCR. Sequencing analysis of PCR products of patients with t(11;18)(q21;q21) was performed.
Results: t(11;18)(q21;q21) was present in 3 patients (15.7%) at diagnosis. Median follow-up was 73 months (13–240). In patients with complete histological remission, monoclonality was demonstrated in 11 out of 19 (58%) and maintained monoclonality in 8 out of 10 (80%) who had sequential studies. All 3 t(11;18)(q21;q21) positive patients had maintained monoclonality and sequencing analyses revealed the presence of the same mutated IgVH alleles in diagnostic and in follow-up samples. In contrast, in 2 cases without t(11;18)(q21;q21) the monoclonal rearrangements corresponded to unrelated alleles. Persistent monoclonality was detected after a median of 49 months (6–134) and did not condition histological relapses, either in negative or positive t(11;18)(q21;q21) patients.
Conclusions: More than half of patients with gastric MALT lymphoma achieving histological response after chemotherapy and/or surgery have long term persistent monoclonality. t(11;18)(q21;q21) determines long term persistence of the initial lymphoma population. However, the presence of maintained monoclonality did not determine relapse.
Cytosolic Phospholipase A2α (cPLA2α) Functions at the Nexus of Bidirectional Integrin Signaling in Platelets.
Authors: Prevost Nicolas , Mitsios John V. , Shimizu Takao , Shattil Sanford J. 
Published: October 2019

Abstract
cPLA2 catalyzes the release of arachidonic acid from the sn-2 position of platelet membrane glycerophospholipids, leading via cyclooxygenase to the production of thromboxane A2 (TXA2), a platelet agonist. One function of TXA2 and other platelet agonists is to activate the fibrinogen-binding function of integrin αIIbβ3 through a series of biochemical steps known as inside-out signaling. While some platelet agonists stimulate cPLA2 activity and TXA2 production during inside-out signaling, others appear to require fibrinogen binding to αIIbβ3 and subsequent outside-in signaling through the integrin to elicit TXA2 production. However, the precise relationship between cPLA2 and αIIbβ3 is unclear. Here we have discovered that cPLA2α, the principal cPLA2 isoform in platelets, interacts with αIIbβ3 and participates in both inside-out and outside-in integrin signaling. A pool of cPLA2α was constitutively associated with αIIbβ3 in human and murine platelets, as determined by co-immunoprecipitation with antibodies to cPLA2α or αIIbβ3. Although the mode of interaction of cPLA2α with αIIbβ3 is unknown, vimentin, an intermediate filament protein known to bind to cPLA2α and integrin β tails, co-immunoprecipitated with both cPLA2 and αIIbβ3 from platelets. Selective induction of fibrinogen binding to platelets by MnCl2 caused a detectable increase in cPLA2 activity in both whole platelet extracts and αIIbβ3 immunoprecipitates. However, this response was not observed in platelets from mice deficient in cPLA2α or in human platelets pre-treated with pyrrophenone, a selective cPLA2α inhibitor. Integrin-dependent activation of cPLA2α had functional consequences. First, thromboxane A2 produced in response to fibrinogen binding to αIIbβ3 was required for the recruitment of activated protein kinase Cβ to the αIIbβ3 signaling complex, an event known to be required for cytoskeletal reorganization and full platelet spreading on fibrinogen. Second, platelets from cPLA2α-deficient mice exhibited reduced spreading on fibrinogen compared to platelets from wild-type littermate controls (P < 0.05). Similarly, human platelets pre-treated with either pyrrophenone or a thromboxane A2 receptor antagonist spread poorly on fibrinogen compared to vehicle-treated control platelets (P < 0.05). Third, cPLA2α-deficient platelets stimulated by the GP VI collagen receptor agonist, CRP, exhibited decreased binding of soluble fibrinogen (P < 0.05). These studies establish that cPLA2α can function in association with αIIbβ3 to produce a pool of TXA2 that promotes integrin-dependent activation of protein kinase Cβ, cytoskeletal reorganization and platelet spreading. Given the previous demonstration of prolonged bleeding times and protection from thromboembolism in cPLA2α-deficient mice, these results imply that normal platelet function requires cPLA2α activation both upstream and downstream of αIIbβ3.
Development of RAD51 as Biomarker for Sensitivity to the Histone Deacetylase (HDAC) Inhibitor PCI-24781 in Lymphoma.
Authors: Balasubramanian Sriram , Adimoolam Shanthi , Sirisawad Mint , Evens Andrew M. , Gordon Leo I. , Miller Richard , Buggy Joseph J. 
Published: October 2019

Abstract
Histone deacetylase inhibitors are currently under investigation in the clinic for a variety of malignancies, and one was recently approved for treating cutaneous T-cell lymphoma. We demonstrate here that a novel, orally bioavailable HDAC inhibitor currently in clinical trials, PCI-24781, demonstrates very good activity against lymphoid tumor lines in vitro as well as against primary tumor cells from lymphoma patients cultured ex vivo. Further, we demonstrate the potential of predicting sensitivity to PCI-24781 in lymphoma by measuring expression levels of RAD51, a protein essential for DNA repair by homologous recombination (HR) following exposure to DNA damaging agents. We have recently shown that RAD51 is downregulated by PCI-24781 treatment in solid tumor lines, and this leads to the inhibition of homologous recombination, absence of RAD51 foci and ultimately to apoptosis. However, little is known about the role of RAD51 in lymphoma. In this work, we show that RAD51 is expressed in human lymphoma by immunohistochemical staining of tissue microarrays (TMA) containing over 90 primary tumor sections (50 follicular lymphomas and 40 DLBCL). We found that a majority of these (65%) express significant levels of RAD51. Further, we measured RAD51 protein and mRNA levels in 8 non-Hodgkins lymphoma cell lines, including those derived from B- and T-cell lymphomas, before and after a 24 hour exposure to PCI-24781 at physiologically relevant concentrations. We found that there was a strong correlation between the percentage of apoptotic cells following PCI-24781 treatment as assayed using Annexin V/propidium iodide and the decrease in the level of RAD51 expression, with each of the five cell lines with >70% apoptosis following drug treatment also showing >4 fold decrease in RAD51 mRNA. These cell lines also had the highest pretreatment levels of RAD51. Thus, both the initial level of RAD51 in tumors as well as the fold decrease after treatment are predictive for PCI-24781 activity, and will be used as biomarkers in clinical studies to identify patients most likely to respond to PCI-24781.
Tipifarnib Is Cytotoxic and a Drug Transporter Inhibiting Chemosensitizer in Hodgkin Lymphoma Tumor Cells.
Authors: Boll Boris , Lang Anna , Langendorf Peer , Hansen Hinrich P. , von Strandmann Elke P. , Engert Andreas , von Tresckow Bastian 
Published: October 2019

Abstract
INTRODUCTION: Patients with Hodgkin lymphoma (HL) still suffer from late toxicities and insufficient treatment of relapses. New therapies should therefore be established. Tipifarnib is a farnesyl transferase inhibitor with an excellent toxicity profile and clinical activity in hematologic malignancies. Recently, tipifarnib has also been shown to potentiate the cytotoxicity of anthracyclines in leukemia cells via the inhibition of the multidrug resistance transporter P-glycoprotein. To date, nothing is known about a functional role of drug resistance transporters or the effects of tipifarnib in HL.
METHODS: To test the anti-tumor effects of tipifarnib in HL cell lines, tipifarnib was evaluated in the XTT cytotoxicity assay and the Annexin V binding assay. The combination efficacy of tipifarnib with the anthracycline doxorubicine was monitored using the Chou and Talalay combination index method. Flow cytometry was applied to assess the effects of tipifarnib on drug transporter mediated anthracycline efflux.
RESULTS: First, tipifarnib displayed high single agent toxicity in HL cell lines with an average IC50 of < 0.1 μM. Second, the combination of tipifarnib and doxorubicine was highly synergistic at clinically relevant concentrations (1–3 μM and 0.02–0.2 μM, respectively). Third, measurement of residual doxorubicine after incubation with doxorubicine and tipifarnib indicated a strong inhibition of doxorubicine efflux by tipifarnib suggesting a mechanism for the synergy of the two drugs.
CONCLUSIONS: Since tipifarnib displays high activity in a panel of HL cell lines, the clinical evaluation of tipifarnib in relapsed/refractory patients as single agent is warranted. Interestingly, tipifarnib exhibits a dual targeting mechanism in HL cells: Potent cytotoxicity as single agent and drug transporter dependent chemosensitization leading to a strong synergy with doxorubicine. The synergistic combinations of tipifarnib with doxorubicine correspond to plasma levels of the two drugs in cancer patients. Doxorubicine is one of the most effective but also most toxic drugs in the standard HL polychemotherapies whereas tipifarnib has a very favourable toxicity profile. Consequently, tipifarnib should be evaluated as a combination drug for HL polychemotherapy to save on doxorubicine dose and to lower acute and long-term toxicities. Tipifarnib might also be examined as a chemosensitizer for the combination therapy of patients with refractory disease.
Synergy of the Purine-Scaffold HSP90 Inhibitor, PU-H71, with Doxorubicin in Non-Hodgkin’s Lymphoma Cell Lines.
Authors: Varticovski Lyuba , Wright Mollie H. , Caldas-Lopes Eloisi , Chiosis Gabriela , Robles Ana I. 
Published: October 2019

Abstract
For over 30 years CHOP (cyclophosphamide-doxorubicin-vincristine-prednisolone) has been the standard therapy for Diffuse Large B-cell Lymphoma (DLBCL). Although DLBCL is one of the most chemotherapy-responsive human malignancies, less than 50% of newly diagnosed patients are cured with the conventional anthracycline-based chemotherapy. Novel strategies are sought out to improve the survival of these patients. Heat Shock protein 90 (HSP90) is a molecular chaperone critical for correct conformational folding of many cellular proteins. Many of those proteins are signal-transducing regulators of cell growth, DNA damage response, and survival. Cancer cells are particularly dependent on these regulators for maintenance of the transformed phenotype. Thus, HSP90 is an attractive target for cancer therapy. HSP90 inhibitors block the ATP-binding pocket and inhibit an essential ATPase activity, altering the function of the HSP90 complex and leading to destabilization and eventual degradation of mis-folded proteins. Inhibitors of HSP90 have shown promise alone or in combination with chemotherapy or radiation in preclinical studies, and are currently undergoing PhaseI/II clinical trials. Future clinical trials on their efficacy will likely explore if any additional benefit is apparent from their combination with conventional therapies. We recently demonstrated that schedule of administration of 17DMAG following Doxorubicin (DOX) ia critical for in vitro sensitivity of DLBCL cells. We examined whether the newly developed purine-scaffold HSP90 inhibitor, PU-H71, could similarly enhance the toxicity of cells to DOX when applied 24 hours after exposure to DOX. We found that sequential addition of PU-H71 to DOX resulted in reduction of DOX IC50, from 400 nM to 75 nM. To evaluate the role of schedule of drug exposure as a determinant of the overall response, we analyzed the interaction of DOX and PU-H71 on cell survival. We applied standard criteria for synergy: the median effect/Combination Index (CI) method using an equimolar (1:1) ratio of DOX:PU-H71. Addition of PU-H71 to cells pretreated with DOX for 24 hours was consistently synergistic over the entire range of drug doses, with CI = 0.75 at Fa = 0.5. Although addition of PU-H71 prior to DOX was synergistic with CI = 0.7 at Fa = 0.5, this was only evident for higher doses. Only additive-to-antagonistic effects were observed at lower drug concentrations (Fa < 0.3). These results raise the question on whether synergy between PU-H71 and DOX will be observed at the concentrations achievable clinically. Conclusions: our observations provide a rationale for further preclinical testing and stress the need to consider schedule of exposure as a critical determinant of the overall response when designing clinical trials that combine HSP90 inhibitors with DNA damaging agents.
The Proteasome Inhibitor BSc2118 Causes Growth Inhibition, Cell Cycle Arrest and Cyclin D1 Degradation in Mantle Cell Lymphoma Cell Lines.
Authors: Jakob Christian , Sterz Jan , von Metzler Ivana , Kuckelkorn Ulrike , Braun Hannes A. , Rötzer Susanne , Kaiser Martin , Heider Ulrike , Rademacher Jessica , Kloetzel Peter M. , Sezer Orhan 
Published: October 2019

Abstract
The ubiquitin-proteasome complex has recently been identified as a novel therapeutic target, particularly in hematological malignancies. An increased proteasome activity has been described in certain types of malignant cells including mantle cell lymphoma (MCL). The proteasome inhibitor bortezomib has shown in vitro activity in MCL cell lines and also clinical efficacy in patients with refractory or relapsed MCL. We previously described a novel tripeptide compound, BSc2118 which inhibits all three proteolytic activities of the 20S proteasome and has anti-tumor activity in melanoma and multiple myeloma (Cancer Res2006; 66: 7598–7605). We investigated the anti-tumor effects of BSc2118 in the MCL cell lines HBL-2, JeKo-1 and Granta-519 and studied its effects on cell cycle progression and the expression of the cell cycle regulatory proteins p21, p27 and cyclin D1. Furthermore the inhibition of intracellular proteasome and NF-kappa B activity was analyzed in MCL cells. In MCL cell lines HBL-2, JeKo-1 and Granta-519, BSc2118 caused a time- and dose-dependent growth inhibition, an induction of apoptosis and a dose-dependent inhibition of intracellular proteasome activity. After 24 and 48 hours of incubation with 40 – 260 nM BSc2118 we found a time- and dose-dependent cell cycle arrest in G2/M phase in all three MCL cell lines. Furthermore we could demonstrate a dose-dependent stabilization of p21 and a degradation of cyclin D1 in western blot analysis. No significant changes could be seen in p27 expression under proteasome inhibition with BSc2118. After TNF-alpha stimulation we found a low NF-kappa B activity also in untreated MCL cells, which could be partially inhibited by preincubation with BSc2118. In this study we show the effects of the novel proteasome inhibitor BSc2118 on cell cycle and growth inhibition in MCL cells lines and furthermore demonstrate that inhibition of proteasome activity, cyclin D1 degradation and p21 stabilization are crucial mechanisms of action for this compound in MCL. Since recent trials have shown a clinical efficacy of proteasome inhibition in MCL, our preclinical data suggest to consider BSc2118 as a novel agent in drug development against MCL.
Identification of Pleiotrophin as a Novel Growth Factor for Hematopoietic Stem and Progenitor Cells.
Authors: Himburg Heather , Muramoto Garrett , Meadows Sarah , Salter Alice , Zi Ningyi , Chao Nelson J. , Chute John P. 
Published: October 2019

Abstract
Hematopoietic stem and progenitor cells have been demonstrated to reside in association with bone marrow sinusoidal endothelial cells in vivo but the mechanisms through which the BM vascular niche regulates hematopoiesis remains incompletely defined. In an attempt to identify candidate soluble growth factors for hematopoietic stem cells (HSCs) which are produced by endothelial cells (Ecs), we have performed comparative genome-wide expression analysis of a primary human brain-derived Ecs which we have previously demonstrated to support a 10-fold expansion of human SCID-repopulating cells (SRCs) in non-contact cultures. This analysis revealed that pleiotrophin (PTN), a heparin binding growth factor, was 32-fold overexpressed in HUBECs that supported human HSC expansion as compared to non-supportive EC lines. Pleiotrophin has anti-apoptotic, mitogenic and transforming activities, suggesting a role in tumorigenesis. No role for pleiotrophin in hematopoiesis has been described. In order to determine if PTN contributes to the demonstrated HSC-supportive activity of HUBECs, the activity of PTN was blocked by adminstration of a neutralizing anti-PTN mAb to the coculture model. Three doses of PTN neutralizing antibody (5, 25, and 50 ug/ml) were added to non-contact cocultures of HUBECs with human cord blood CD34+CD38-lin- HSCs. The anti-PTN treatment caused a decrease in the numbers of phenotypic HSCs in culture in a dose dependent manner. Relative to control HUBEC cultures, the % and expansion of CD34(+) progenitors decreased signficantly at the two higher doses of anti-PTN (p<0.05, respectively). Additionally, CD34(+)CD38(−) lin(−) progenitors were decreased by 33% at the highest dose of anti-PTN compared to control HUBEC cultures (p<0.05). Transplantation studies of anti-PTN treated versus control HUBEC-cultured progeny into NOD/SCID mice are ongoing to confirm the central role of PTN in the expansion of human HSCs in culture. In a correlative study, the addition of recombinant PTN to cultures of human HSCs with thrombopoietin, SCF and flt-3 ligand was shown to significantly increase CD34+ cell content and CD34+CD38- cell content compared to cytokines alone, again in a dose-dependent manner. Taken together these results suggest that PTN, a growth factor with no previously ascribed hematopoietic activity, is a soluble growth factor for human hematopoietic progenitor cells. Since blockade of PTN activity significantly inhibits the soluble activity of HUBECs to support human HSC proliferation and expansion, PTN is also a candidate growth factor for further study in the context of understanding the function of the BM vascular niche.