bluuebunny/crossref_metadata_2025_split huggingface dataset:
Rituximab-Mediated Inhibition of the PI3K-Akt Survival Signaling Pathway in B-NHL Cell Lines Leading to Downregulation of Bclxl Expression and Chemosensitization.
Authors: Suzuki Eriko , Jazirehi Ali R. , Bonavida Benjamin 
Published: April 2020

Abstract
Rituximab (chimeric anti-CD20 monoclonal antibody) has been used in the treatment of B-NHL. We have reported in vitro that rituximab treatment signals B-NHL cell lines Ramos and Daudi and inhibits both the ERK 1/2 MAPK and NF-κB signaling pathways leading to selective inhibition of Bclxl expression and sensitization to drug-induced apoptosis. The inhibition of the NF-κB signaling pathway by rituximab was shown to be due, in part, to the induction of the Raf Kinase Inhibitor Protein (RKIP) (Jazirehi, et al., 2005 Cancer Research 65:264–276). The PI3K-Akt signaling pathway is a key regulator of cell survival and aberrant activation of the PI3K-Akt pathway has been implicated in both drug resistance and resistance to apoptosis-inducing stimuli. Akt can promote cell survival by indirectly activating the proximal transcription factor NF-κB through the phosphorylation of I-kappa B kinase (I-κB) (Ozes et. al. Nature401:82–85, 1999). This study investigated whether NF-κB inhibition by rituximab and downregulation of Bclxl expression was also the result of rituximab-mediated inhibition of the PI3K-Akt pathway. Ramos and Daudi B-NHL cell lines were treated with rituximab (20 ug/ml) and cell lysates were prepared and both Akt and phospho-Akt (p-Akt) expression were examined by western blot. The findings demonstrate that both cell lines show constitutively activated p-Akt and treatment with rituximab significantly inhibited p-Akt but not Akt. Time kinetics analysis demonstrated that inhibition of p-Akt was first detected at 3–6 hours following rituximab treatment and inhibition was maintained up to 24 hours. Concomitantlly, a similar time kinetics revealed inhibition of NF-κB activity as assessed by EMSA. Since the inhibition of NF-kB activity resulted in significant downregulation of Bclxl expression, we also examined the role of the Akt pathway in the regulation of Bclxl expression. Tumor cells were treated with the Akt inhibitor LY294002 and analysis of cell lysates showed significant downregulation of Bclxl expression. Rituximab was previously shown to sensitize B-NHL cells to drug-induced apoptosis via inhibition of NF-κB activity and Bclxl expression. We examined if inhibition of the Akt pathway also chemosensitized the cells. Treatment of Ramos cells with the Akt inhibitor LY294002 significantly sensitized the cells to CDDP-induced apoptosis and synergy was achieved. Altogether, these findings demonstrate, for the first time, that rituximab inhibits the Akt pathway and that this pathway is involved in the regulation of tumor- cell resistance to chemotherapeutic drugs. This study also proposes that the Akt pathway is a potential targeting pathway for therapeutic intervention in the treatment of rituximab and drug-resistant B-NHL.
A Very Short Mutational Hot-Spot in the IGH 5′Sμ Region Suggests That the Acquisition of a Class Switch Recombination Defect Is an Important Step Toward Lymphomagenesis.
Authors: Ruminy Philippe , Jardin Fabrice , Penther Dominique , Parmentier Françoise , Buchonnet Gérard , Picquenot Jean-Michel , Tilly Hervé , Bastard Christian 
Published: April 2020

Abstract
The t(14;18), which occurs during VDJ joining, is usually seen as the primary genetic event in follicular lymphoma (FL). Pre-lymphoma cells would then migrate to the secondary lymphoid organs and acquire secondary genetic abnormalities. The mechanisms leading to these secondary lesions are unclear, but both somatic hypermutation (SHM) and class switch recombination (CSR) processes may be involved. Surprisingly, while many FL still express an IgM, aberrant switch junctions were reported on both IGH alleles, indicating dysfunctions of CSR during the onset of the neoplasm. Recently, AID mediated point mutations were shown to accumulate in the switch μ (Sμ) regions of stimulated B cells undergoing CSR. To get insights into a possible CSR deregulation in FL, we sequenced the 5′ end of the Sμ region for 73 t(14;18) positive tumours. 152 point mutations and 5 deletions were identified, for a mutation frequency of 0.31/100 bp. Notably, mutations were found for a majority of cases (49/73, 67.1%) rather than being restricted to few tumours. Significant targeting of RGYW motifs (p&lt;10−4) and bias for transitions over transvertions (p&lt;10−4) both suggested the involvement of AID. More importantly, our data showed a highly significant clustering effect, with 22 mutations (13,9%) found on a 4 bp cluster on the GTAA splicing donor site of the Iμ exon (p&lt;10−6). Those 22 mutations were found in different tumors so that 30.1% of the lymphomas in our series had a mutated splicing site. Analysis of whole blood genomic DNA from 14 patients and 20 healthy donors indicated that these mutations are not polymorphisms but are instead acquired by tumor cells. Importantly, allele specific PCR experiments showed no clustering effect on the translocated alleles, while 15/79 (19%) mutations on the functional alleles were found on the Iμ splicing site (p&lt;10−6). Such mutations were also found, but on the translocated alleles, for two additional lymphomas with complex t(3;14;18)(q27;q32;q21) and t(8;14;18)(q24;q32;q21) translocations, suggesting that they may be linked to downstream rearrangements on the IGH locus. Finally, RT-PCR experiments showed that a mutation of the Iμ splicing site leads to the expression of aberrant germline transcripts. Together, our data thus indicate that mutations leading to an incorrect splicing of the germline Sμ transcripts are probably positively selected during lymphomagenesis, and therefore that an acquired perturbation of the CSR process may have a major impact during the onset of the disease, maybe by preventing pre-lymphoma cells from switching their surface immunoglobulin and/or by favouring subsequent genetic lesions.
CD56+ Monomorphic Enteropathy-Type T-Cell Lymphoma Is a Genetically Distinct Entity Characterized by 8q Gains and Lack of 1q and 5q Gains.
Authors: deLeeuw Ronald J. , Zettl Andreas , Trottier Magan , Gascoyne Randy D. , Chott Andreas , Mueller-Hermelink Hans K. , Lam Wan L. 
Published: April 2020

Abstract
Introduction: Enteropathy-type T-cell Lymphoma (ETL) is a highly aggressive extranodal T-cell non-Hodgkin’s lymphoma that is often associated with underlying celiac disease. In this study we used whole genome tiling resolution array comparative genomic hybridization (CGH) to delineate genomic changes that may be critical in disease pathogenesis in 30 well-characterized cases of ETL, among them 14 cases of CD56+ monomorphic small to medium-sized ETL, so-called small cell variant (CD56+smETL).
Experimental Approach: Whole genome tiling array CGH was used to generate high resolution segmental copy number profiles of 30 ETL specimens, the array platform consisting of 26,819 bacterial artificial chromosome (BAC) derived amplified fragment pools spotted in duplicate.
Results: Alignment of these profiles with the human genome map has resulted in the identification of both previously reported and novel regions of recurrent genomic alteration. The most frequently identified recurrent chromosomal gains were 9q34.11-qter (approx. 10.2 Mb; 70%), 9q33.2-q33.2 (6.6 Mb; 67%), 9q31.3-q33.2 (13.8 Mb; 60%), 5q34-q35.2 (6.5 Mb), 7q33-q34 (2.4 Mb, 47% each), 1q25.3-q31.2 (8.4 Mb), 1q32.2-q41 (7.9 Mb), 7q22-q31.1 (5.6Mb), 7q36.1-qter (9.6Mb, 43% each), 8q13.3–8q21.11 (3Mb), and 8q22.1-q24.3 (46.2 Mb, 40% each). Frequent recurrent chromosomal losses were observed on 8p22-p23.2 (15.3Mb, 37%), 10q26.2-q26.3 (5.5Mb, 27%), and 9p21.2-p21.3 (4.9Mb, 23%). Interestingly, the most frequent gains at 9q34.11-qter were inversely correlated with losses at 16q12.1 (2.5Mb, 23%, p=0.0139), suggesting these regions may accomplish similar biological effects. CD56-positive monomorphic small cell ETL were characterized by highly recurrent gains of 8q13.3-q21.11 and 8q22.1-q24.3 (71.4% in CD56+smETL vs 18.8% in non-monomorphic ETL, p=0.0086) and the rare occurrence of gains on 1q25.3-q31.2 and 1q32.2-q41 (21.4% in CD56+smETL vs 62.5% in non-monomorphic ETL, p=0.0329) and 5q34-q35.2 (21.4% in CD56+smETL vs 68.8% in non-monomorphic ETL, p=0.0136) which are common within non-monomorphic ETL.
Conclusions: ETL show highly recurrent and characteristic gains and losses of chromosomal material. While gains of chromosome 9q (detected in 70% of ETL) appear to be the hallmark genetic alteration in ETL, ETL, in line with differences in morphology, immunophenotypes and clinical features, seems to be also genetically subdivided into two distinct sub-groups: CD56+monomorphic small to medium sized ETL characterized by gains of 8q and CD56-negative non-monomorphic ETL characterized by gains of 1q and 5q.
The Leukemia Oncogene E2a-Hlf Impairs Checkpoint Activation.
Authors: Porter Christopher C. , DeGregori James V. 
Published: April 2020

Abstract
The E2a-Hlf oncogene results from the translocation of chromosomes 17 and 19. This is a rare translocation found in pro-B cell leukemia cells of older children and adolescents. However, the resulting leukemia has been fatal in all reported cases despite intensive therapy. Evidence suggests that E2a-Hlf contributes to leukemogenesis by impairing apoptosis, but the precise molecular mechanisms of malignant transformation are not well understood. We have observed that E2a-Hlf confers a survival disadvantage relative to un-transduced cells and hypothesize that impaired checkpoints play a major role in genetic instability, malignant transformation, and resistance to therapy. In retrovirally transduced murine pro-B lymphocytes (FL5.12) we have observed that when co-cultured with un-transduced cells, the percentage of E2a-Hlf expressing cells diminishes over time. Furthermore, after retroviral transduction of wild-type primary hematopoietic progenitor cells and transplantation into lethally irradiated recipients, E2a-Hlf expressing cells are undetectable after 2 weeks. In contrast, after transduction and transplantation of replication impaired hematopoietic progenitors (E2F1 and E2F2 mutated), E2a-Hlf expressing cells persist for up to 6 months. We have also observed a survival disadvantage in fibroblasts, indicating that the effect is not tissue specific. When exposed to genotoxic agents such as bleomycin, E2a-Hlf expressing cells have substantially decreased activation of the checkpoint proteins p53, Chk1, and Chk2 as determined by Western blot analysis using phospho-specific antibodies. This effect appears to be downstream of DNA damage focus formation, as levels of ATR and phosphorylated ATM (Western blotting) and gamma-H2AX foci formation (immunofluorescence) are not affected by E2a-Hlf expression. Future studies will be directed at determining how checkpoint activation is inhibited by E2a-Hlf. A better understanding of the molecular mechanisms of E2a-Hlf mediated malignant transformation may lead to targeted and more effective therapy.
Dominant Negative Effect of Kinase-Inactive Bcr-Abl on Cell Survival and DNA Damage Response Pathways in Imatinib-Treated Cells.
Authors: van der Kuip Heiko , Fiesel Fabienne , Moehring Alexandra , Aulitzky Walter E. 
Published: April 2020

Abstract
Imatinib inhibits cell proliferation and induces cell death in BCR-ABL positive leukemic cells in the absence of exogenic growth factors in vitro. In this study, we investigated the effects of physiological growth factors on cell survival and DNA damage response in Imatinib treated Bcr-Abl positive and Bcr-Abl negative cells from murine and human origin. To this end, we used 32D and 32D/bcr-abl, BaF3 and BaF3/bcr-abl, and M07 and M07bcr-abl cell lines. All bcr-abl positive cell lines were highly sensitive to Imatinib in the absence of growth factors. mIL3 protected Bcr-Abl transformed murine cell lines from Imatinib-induced cell death but was not capable to restore the Imatinib-dependent blockade of the p53 response to cisplatinum or gamma irradiation in Bcr-Abl positive cells. Despite prolonged pre-incubation with mIL3, Imatinib led to a transient inhibition of PI3K-, MAPK-, and STAT5-pathways selectively in Bcr-Abl positive murine cells. Importantly, this transient blockade of survival pathways by Imatinib was completely abolished after simultaneous siRNA-mediated suppression of Bcr-Abl synthesis. In contrast to the murine cell lines, Bcr-Abl positive human megakaryocytic M07 cells can not be rescued from Imatinib-induced cell death. Imatinib treated cells died even when pre-incubated simultaneously with a growth factor mix consisting of hGM-CSF, hSCF, and hIL3. Suppression of Bcr-Abl synthesis by RNAi using a breakpoint-specific siRNA selectively inhibited Bcr-Abl-dependent growth of M07/bcr-abl cells to an extent comparable to that observed with Imatinib. Importantly, growth factor stimulation enabled survival of M07/bcr-abl cells after suppression of Bcr-Abl synthesis by siRNA but not after Imatinib-mediated inhibition of Bcr-Abl kinase activity.
In summary, our results indicate a dominant negative effect of kinase-inactive Bcr-Abl both on survival and on DNA damage response pathways.
Transplantation of Haplo-Identical Bone Marrow-Derived Mesenchymal Stem Cells Together with Hematopoietic Stem Cells To Promote Engraftment in Children. A Phase I/II Multicenter Study.
Authors: van Velzen-Ball Lynne Margaret , Le Blanc Katarina , Lankester Arjen C. , Roelofs Helene , Egeler Maarten , Frassoni Francesco , Ringdén Olle , Fibbe Willem E. 
Published: April 2020

Abstract
Graft failure or rejection is an identified problem in haplo-identical or second attempt transplantation. In the bone marrow, mesenchymal stem cells (MSCs) have been identified and shown in animal models to enhance hematopoietic stem cell (HSC) engraftment. Advances in techniques and higher quality culture components have allowed the development of an MSC expansion procedure resulting in sufficient MSCs for clinical application. Adult studies have suggested that co-transplantation of MSCs and HSCs in the HLA-identical setting, is feasible and safe.
Here we present the first combined clinical experience within the EBMT MSC expansion consortium with respect to co-transplantation of haplo-identical MSCs in the pediatric allogeneic transplantation setting.
Six weeks before the SCT, 50 cc of bone marrow are sampled under sterile conditions. Density gradient-separated MNCs are plated into tissue culture flasks in low-glucose DMEM supplemented with 10% fetal calf serum and incubated at 370C with 5% CO2. At 70% confluence, the cells are trypsinized and re-plated at 4x103 cells/ cm2 until the target dose of 1–2 x106/kg recipient body weight is obtained. Enrichment and expansion of MSCs is performed under GMP conditions in nationally accredited laboratories. MSCs (either fresh or cryopreserved) are administered i.v. 4 hours before infusion of donor HSCs. To date 4 children have undergone co-transplantation. Patient characteristics are summarized in the table. All toxicities associated with the procedure were documented, as were the engraftment kinetics and immune recovery. The study was carried out with approval of the respective local ethical committees.
The data indicate that expansion and co-transplantation of MSCs is feasible and well tolerated. While the study is ongoing initial engraftment and immune recovery data (compared to historical data) is encouraging and to date there have been no episodes of graft rejection or severe adverse events related to this treatment.
Patient characteristics Patient demographics HSC characteristics MSC characteristics UPN Gender Age Diagnosis Donor CD34 dose (106/kg) Donor Cell dose (106/kg) 1 M 15 ANLL mother-haplo 16 mother 1.5 2 M 2 XLPD father-haplo 20 father 1.9 3 M 2 XLPD father-haplo 18.7 father 1.56 4 M 8 SAA URD (2 loci mismatched) 2.65 mother 1.0
The Role of GM-CSF in Haplo-Identical Transplant Patients Who Do Not Benefit from NK Alloreactivity.
Authors: Lewalle Philippe , Delforge Alain , Nowak Berengere , Misplon Virginie , Bennani Jalil , Bron Dominique , Martiat Philippe 
Published: April 2020

Abstract
Haplo-identical transplant is now established as a procedure of choice for patients who lack a compatible donor. It might even be the best choice for AML, provided there is a GvH NK allo-reactivity. However, patients are still referred too late, heavily pre-treated, at very advanced stages. We initiated a three-step phase I study trying improve transplant related mortality, relapse rate and immunity:
: G-CSF + DLI, : GM-CSF + DLI, : patient and disease adapted strategy.
Thirty-six consecutive leukemia patients, aged 18–55, were investigated (20 very poor risk, 12 poor risk and 4 better risk). GvH type NK alloreactivity was chosen when possible (21/36) and balanced across the 3 groups. In the first 9 patients, G-CSF was used pot-transplant and prophylactic DLI were given at month 1, 2 and 3. The use of G-CSF and 1 to 3 DLI (10exp4 CD3/kg) was found safe. It resulted in faster CD4 recovery and a low rate of infections. However, it was insufficient to induce a protective GVL effect. In the next 12 patients, GM-CSF was used plus 1 DLI (104 CD3/kg) at day 30 unless aGVHD (3 pts). The comparison between the 2 first groups can be summarized as follows: G-CSF + DLI: TRM at day 100: 0, RR: 6/9, severe aGVHD:0. GM-CSF + 1 DLI group: RR: 1/12, TRM at day 100: 3, aGVHD grade 2 or more: 9/12; price to pay: GVHD resulting in 5 deaths in total. Median time to relapse in the 21 first patients was 6 months range (4 – 9). Step 3 (17 patients) consists of a patient adapted strategy: no more aspecific DLI (selected anti-CMV and aspergillus DLI planned in all patients); in myeloid disorders with NK allo-reactivity: no GF. In the other cases, GM-CSF (at a reduced total dose of 500 mcg) is given from day 5 to day 9. The follow-up of patients alive in CCR (12), although promising (3 relapses), is currently short (median 8 months), compared to the median of relapse in the 2 first groups (6 months). Overall, TRM at day 100 is 2/29, reflecting the good tolerance of the conditioning in a heavily pre-treated population (median age: 43). Overall relapse rate for all patients treated with GM-CSF, without the benefit of NK-alloreactivity, is 6/16 (median FU: 15 months). We conclude that the third strategy might improve the outcome and the relapse rate without exposing patients to unnecessary severe GVHD. These data will be updated with 6 months more follow-up and 3 more patients.
Outcome of Non-T-Cell-Depleted Hematopoietic Stem Cell Transplantation between HLA-Haploidentical Non-Inherited Maternal Antigen (NIMA)-Mismatched Family Members in Childhood.
Authors: Yoshihara Takao , Okada Keiko , Yabe Hiromasa , Kobayashi Michihiro , Kikuta Atsushi , Kato Koji , Adachi Naoto , Kikuchi Akira , Hirota Yasuzou , Kuroda Hiroshi , Nagatoshi Yoshihisa , Inukai Takeshi , Koike Kazutoshi , Kigasawa Hisato , Tanaka Ryuhei , Watanabe Arata 
Published: April 2020

Abstract
Sporadic cases of successful non-T-cell-depleted (TCD) hematopoietic stem cell transplantation (SCT) from HLA-haploidentical family members mismatched for noninherited maternal antigens (NIMAs) have been reported over the last few years. This kind of SCT is based on the hypothesis that long-term feto-maternal microchimerism is associated with acquired immunologic hyporesponsiveness to NIMA or inherited paternal antigens (IPAs). To confirm the effectiveness and safety of NIMA-mismatched SCT in a large cohort, we retrospectively surveyed the outcomes of 76 children (44 boys, 32 girls; median age 7 years, range, 0–18) with either advanced non-malignant disorders (n=10), hematological malignancies (n=62) or solid tumors (n=4) who underwent T-cell-replete HLA-2-loci- or HLA-3-loci incompatible SCT from NIMA-mismatched donors (mother, n=53; NIMA-mismatched sibling, n=12) or other family donors (father/NIPA-mismatched sibling) (n=11) between 01/2000 and 12/2004. Disease status of malignant disease at SCT was as follows: CR1/CR2/CP in 19 and chemorefractory in 47. Types of grafts were bone marrow in 40 and peripheral blood stem cells in 35. Feto-maternal michrochimerism was detected in 32 out of 35 mothers tested and 8 out of 8 NIMA-mismatched sibling donors. GVHD prophylaxis consisted of tacrolimus-based regimen in 73. All but two patients achieved sustained neutrophil engraftment at median of 16.5 days (range, 10–29). Grade II to IV acute GVHD occurred in 36 of 73 evaluable patients (49%) between days 7 and 36 (median, 17). In non-malignant disorders, no severe (grade III/IV) acute GVHD was observed, while in malignant disorders, severe acute GVHD occurred in 21 (32%) of 65 evaluable patients. Twenty-two out of 41 evaluable patients (54%) who survived more than 6 months had extensive chronic GVHD. As of 04/2005, in non-malignant disorders, all 9 patients who obtained engraftment were alive. In malignant disorders, twenty-nine out of 66 patients (44%) were alive and 25 of them were disease-free with median follow-up of 25 (range, 4 to 57) months. Death were due to disease progression (n=22), infection (n=6), GVHD (n=4) and others (n=4). These results suggest that pediatric patients who lack immediate access to a conventional stem cell source can obtain successful results with non-TCD transplants from an HLA-haploidentical NIMA-mismatched donor.
Dexamethasone Induces Apoptosis “Ex Vivo” in Chronic Lymphocytic Leukemia Cells with Either Unmutated IgVH Genes or High ZAP-70 Expression.
Authors: Muntanola Ana , Crespo Marta , Gine Eva , Villamor Neus , Montserrat Emili , Bosch Francesc 
Published: April 2020

Abstract
Patients with chronic lymphocytic leukemia (CLL) and unmutated IgVH genes or high ZAP-70 expression have poorer prognosis than those with mutated IgVH genes or low ZAP-70 levels. This is in part related to the resistance of unmutated and ZAP-70 positive cases to treatment agents that induce apoptosis in a p53-dependent manner. It has been suggested that corticosteroids are active in CLL through p53-independent pathways. The aim of this study was to analyze the “ex vivo” response to dexamethasone in CLL cells according to the IgVH mutational status and ZAP-70 expression. Frozen lymphocytes from 60 patients with CLL were analyzed for ZAP-70 expression and IgVH mutational status (n=44). Cells were cultured and treated using fludarabine (5μgr/ml), mitoxantrone (0.5μgr/ml), FCM (fludarabine 1μgr/ml, maphosphamide 1μgr/ml and mitoxantrone 0.5 μgr/ml), and dexamethasone (5.2 μg/mL). Cell viability and apoptosis were determined by annexinV/PI staining and FACscan analysis at three different time points and conditions (0h and 24h without treatment, and 24h with treatment). The expression of glucocorticoid receptor (GR) isoforms alpha, beta and gamma was analyzed by Quantitative RT-PCR in 20 cases. Dexamethasone-induced apoptosis was significantly higher in patients with unmutated IgVH and/or high ZAP-70 expression (≥20%) than in those with mutated IgVH and/or low ZAP-70 expression (median cell viability 65% vs. 81%, respectively; p&lt;0.001). In contrast, mitoxantrone induced higher cell toxicity in patients with IgVH mutations or low ZAP-70 expression (p=0.009). No differences in cell viability were found according to ZAP-70 expression or IgVH mutational status after “ex vivo” treatment with fludarabine or FCM (p=0.649 and p=0.055, respectively). Expression of different GR isoforms was similar in corticosteroid-responders and non-responders. In conclusion, in this study CLL cells with unmutated IgVH genes or high ZAP-70 expression showed a higher cell mortality after “ex vivo” exposure to dexamethasone than those with mutated IgVH genes or low ZAP-70 expression, with no relationship with the expression of the different GR isoforms. These data give conceptual support to trials aimed at determining the role of dexamethasone in the treatment of patients with CLL and poor prognostic features or resistant to fludarabine.
Figure Figure