Proliferation Of Lymphoblasts Research Articles

Paediatric Acute Lymphoblastic Leukaemia: A Narrative Review of Current Knowledge and Advancements.

This review aims to provide an update on current knowledge regarding paediatric acute lymphoblastic leukaemia (ALL), focusing on recent advancements in diagnosis and treatment, as well as future directions in the field. ALL is the most frequently diagnosed paediatric malignancy, with advances leading to a 90% survival rate. The heterogeneity of childhood ALL requires a precise diagnostic algorithm incorporating morphological, immunophenotypic, and cytogenetic analyses. Research is exploring next-generation sequencing and artificial intelligence-aided techniques for future diagnostic approaches. Despite these advancements, global disparities in healthcare access hinder prompt diagnosis and management. The pathophysiology of ALL involves chromosomal and genetic alterations which disrupt cell-cycle regulation and result in uncontrolled lymphoblast proliferation. Environmental factors also contribute to leukaemogenesis. Risk-stratification based on genetic subtypes has significant implications for risk-based therapy. Chemotherapy is administered in three phases: induction, consolidation, and maintenance, with prophylactic intrathecal chemotherapy considered essential. For high-risk, refractory, or relapsed ALL, haematopoietic stem cell transplantation and novel therapies such as tyrosine kinase inhibitors, chimeric antigen receptor T-cell therapy, and blinatumomab immunotherapy, have improved outcomes. Ongoing clinical trials aim to further improve treatment efficacy, reduce toxicity, and increase survival. Although prevention strategies for ALL exist at three levels, the supporting evidence remains limited, highlighting a need for further research. Continued research and clinical trials are essential to addressing the gaps treatment efficacy and prevention strategies. Efforts to improve global healthcare access and integrate novel diagnostic and therapeutic approaches are crucial for advancing outcomes for paediatric patients with ALL.

Knowledge distillation model for Acute Lymphoblastic Leukemia Detection: Exploring the impact of nesterov-accelerated adaptive moment estimation optimizer

Acute lymphoblastic leukemia (ALL) is a malignancy that primarily affects the bone marrow and bloodstream, characterized by the rapid proliferation of immature lymphoblasts. In the realm of medical diagnosis, the integration of artificial intelligence (AI) presents an opportunity to revolutionize the detection of ALL. This integration has the potential to significantly enhance diagnostic accuracy, streamline the diagnostic process, and mitigate the risk of human error, which is particularly valuable when analyzing data collected from monitoring devices. This paper introduces two novel architectures designed for the detection of ALL. The first approach, known as Knowledge Nevestro Classification (KNC), incorporates the concept of knowledge distillation. This method leverages two teacher models, DenseNet and ResNet (50), which have undergone meticulous optimization employing both the Adam and Nadam optimizers. This dual optimization approach allows for a comprehensive evaluation of their respective outcomes. The second approach introduces the Nevestro DenseNet (50) Attention (DAN) architecture, which represents a variant of the DenseNet with Attention (NDA) architecture. This custom architecture is purpose-built for the specific task of ALL detection and has been meticulously fine-tuned using the Nadam optimizer. The results show impressive metrics, with accuracy, sensitivity, specificity, precision, and F1-Score measures reaching 0.991, 0.9945, 0.9924, 0.9945, and 0.9945, respectively.

Acute l acute lymphoblastic leukemia and CAR-T Cell immunotherapy: a literature review

Introduction: The use of CAR-T cells has shown significant results, representing a transformative new treatment option with potentially lasting and even curative responses. This study aims to comprehend CAR-T cell immunotherapy as an innovation for the treatment of B-lineage acute lymphoblastic leukemia (ALL). Methodology: The research was conducted through a bibliographic search in the Medline, PubMed, and Lilacs databases, using the following descriptors: "Acute lymphoblastic leukemia" OR "CAR-T cells" OR "Immunotherapy" and their respective translations into English, between May 2023 and December 2023. Results: The selected studies demonstrated that ALL is a neoplasia with multifactorial etiology, originating in the bone marrow, leading to uncontrolled proliferation of lymphoblasts. However, chemotherapy, despite being the therapeutic method of choice, is considered nonspecific, as the drugs, besides acting on tumor cells, also compromise normal tissues with a high rate of renewal through mitotic division, such as the bone marrow, resulting in adverse reactions. Conclusion: Based on the obtained results, it was possible to conclude that immunotherapy using CAR-T cells has been showing promising results with satisfactory outcomes.

Hypoxia induces dichotomous and reversible attenuation of T cell responses through reactive oxygen species-dependent phenotype redistribution and delay in lymphoblast proliferation

As T cells transit between blood, lymphoid organs, and peripheral tissues, they experience varied levels of oxygen/hypoxia in inflamed tissues, skin, intestinal lining, and secondary lymphoid organs. Critical illness among COVID-19 patients is also associated with transient hypoxia and attenuation of T cell responses. Hypoxia is the fulcrum of altered metabolism, impaired functions, and cessation of growth of a subset of T cells. However, the restoration of normal T cell functions following transient hypoxia and kinetics of their phenotype-redistribution is not completely understood. Here, we sought to understand kinetics and reversibility of dichotomous T cell responses under sustained and transient hypoxia. We found that a subset of activated T cells accumulated as lymphoblasts under hypoxia. Further, T cells showed the normal expression of activation markers CD25 and CD69 and inflammatory cytokine secretion but a subset exhibited delayed cell proliferation under hypoxia. Increased levels of reactive oxygen species (ROS) in cytosol and mitochondria were seen during dichotomous and reversible attenuation of T cell response under hypoxia. Cell cycle analysis revealed maximum levels of cytosolic and mitochondrial ROS in dividing T cells (in S, G2, or M phase). Hypoxic T cells also showed specific attenuation of activation induced memory phenotype conversion without affecting naïve and activated T cells. Hypoxia-related attenuation of T cell proliferation was also found to be reversible in an allogeneic leukocyte specific mixed lymphocyte reaction assay. In summary, our results show that hypoxia induces a reversible delay in proliferation of a subset of T cells which is associated with obliteration of memory phenotype and specific increase in cytosolic/mitochondrial ROS levels in actively dividing subpopulation. Thus, the transient reoxygenation of hypoxic patients may restore normal T cell responses.

An unusual pseudolymphoma in the context of necrotizing fasciitis: A case report.

The diagnosis of lymphoma in routine diagnostics can be challenging due to clinical, morphological and immunphenotypical overlap with unusual reactive processes termed "pseudolymphomas." 45-year-old male that underwent surgical debridement for a necrotizing fasciitis of the thigh with concomitant excision of a regional lymph node. The lymph node demonstrated an architecture-effacing activation and proliferation of lymphoblasts and was initially misdiagnosed as an aggressive lymphoma. Only in consideration of the clinical context and with the help of additional immunohistochemical and molecular analyses the final diagnosis of a reactive lymphadenopathy could be made. No further therapy was required after the final diagnosis of a reactive lymphadenopathy was made. The clinical follow-up was unremarkable, with no evidence of residual disease after 6 months. This case report adds the parafollicular activation and proliferation of blasts and plasmablasts in the drainage area of an active infection to the spectrum of "pseudolymphomas" and reiterizes the importance of placing histopathological findings in the proper context.

Augmented Berlin-Frankfurt-Munster versus GRAALL-2003 in young adults with Philadelphia-negative, B-cell acute lymphoblastic leukemia

Background Acute lymphoblastic leukemia (ALL) is a heterogeneous group of diseases characterized by clonal proliferation of lymphoblasts. Improvement in the outcome of ALL in adolescents and young adult (AYA) patients remains one of the challenging problems in ALL treatment. Aim This study was conducted to compare the outcome of polychemotherapy regimens, augmented Berlin-Frankfurt-Munster (ABFM) regimen and GRAALL-2003, in Philadelphia-negative, B-cell ALL in AYA patients. Patients and methods A single-center retrospective study was performed on AYA patients with Philadelphia-negative, B-cell ALL who were diagnosed between 2013 and 2019. Results A total of 37 patients were included (27 males and 10 females) with a mean age of 22.3 years. Complete remission (CR) rate in the ABFM group was 94.1 versus 75% in the GRALL-2003 group (P=0.1). There was no statistically significant difference regarding relapse rate between both regimens (P=0.2). Regarding toxicities, there was no statistically significant difference between the two regimens apart from ICU admission rate, which was statistically significantly higher in the GRAALL-2003 group compared with the ABFM group (P=0.048); however, it had no influence on the overall survival. Conclusion The outcome of both polychemotherapy regimens, ABFM and GRAALL-2003, was comparable regarding CR rate, relapse rate, overall survival, and toxicity profile apart from a noticeable increased rate of ICU admission in GRAALL-2003 regimen, which makes ABFM regimen the more feasible option in treatment.

Reactive Alterations in Thymic Lymphocytopoiesis to Short-Term Decrease in Deuterium Content in the Body

We studied changes in thymic lymphocytopoiesis induced by a short-term decrease in deuterium content in the body. The experiment was performed on adult male Wistar rats receiving water with lower deuterium content [D]=10 ppm. Increased relative weight of thymus was found after 24 h of consumption. Flow cytometry revealed higher percentage of undifferentiated cells and mature T cells, especially cytotoxic T cells. Hence, lymphocytopoiesis in the thymus is highly sensitive to short-term decrease in deuterium body content. A decrease in the content of deuterium stimulates proliferation of lymphoblasts in the thymus and slows down migration of differentiated T cells. Enhanced generation of cytotoxic T cells under these conditions attests to the role of deuterium in selection of double-positive thymocytes. The revealed shifts are reactive, and their pattern can change later, which requires further research.

Two Hematopoietic Transcription Factors, RUNX1 and FUBP1, Control the Expression of KIT Oncogene in Pre-B Lymphoblasts

Hematopoiesis involves an elaborate network of transcription factors articulated with transcriptional cooperators. RUNX1 geneencodes a transcription factor playing a key role in hematopoiesis. Abnormal functions of RUNX1 protein are implicated in blood cancer, notably in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). To unravel the mechanisms behind the modulation of the transcriptional activity of RUNX1, we performed experiments of RUNX1-specific chromatin immunoprecipitation (ChIP) followed by mass spectrometry, and identified Far Upstream Element Binding Protein 1 (FUBP1) as a potential functional cooperator of RUNX1. The helicase and transcriptional regulator FUBP1 has recently been described to be essential for expansion and self-renewal of hematopoietic stem cells and to function as a potential cancer driver gene in lymphoblastic leukemia. Our goals were to validate the protein interaction between RUNX1 and its putative cooperator FUBP1, to identify gene(s) transcriptionally controlled by both RUNX1 and FUBP1, and finally to demonstrate the biological consequence of the cooperation between RUNX1 and its cooperator FUBP1.Co-immunoprecipitation and colocalization experiments demonstrate that RUNX1 colocalizes with FUBP1 in pre-B cell lines, in pre-B lymphoblasts isolated from BCP-ALL patients, and more generally in other hematopoietic progenitors. To characterize some target genes directly regulated by FUBP1 and RUNX1, we performed ChIP combined with sequencing (ChIP-seq) for FUBP1 and RUNX1. Those binding signals were compared to different histone marks and reveal that a subset of FUBP1 and RUNX1 binding signals are enriched within primed enhancer regions characterized by histone H3K4me1 marks. Our data show that RUNX1 signal is also enriched within FUBP1 regions, demonstrating that they are often retrieved on same chromatin regions, bound by FUBP1. Interestingly, FUBP1 is widely distributed in the genome, therefore only a subset of RUNX1 binding signals overlaps with FUBP1 binding signals. To go further, using qPCR, we investigated the expression level of several potential target candidate genes in pre-B cells overexpressed for FUBP1 or RUNX1. We found that both FUBP1 and RUNX1 positively regulate KIT transcript. KIT is a tyrosine kinase receptor expressed on hematopoietic progenitors cell surface and is an oncogene overexpressed notably in different types of leukemia. With the comparison of data from FUBP1 and RUNX1 ChiP-seq, we found that FUBP1 and RUNX1 share two common DNA binding regions on KIT gene, including one overlapping with histone H3K4me1 mark. ChIP-qPCR analyses confirm the binding of FUBP1 and RUNX1 on the KIT enhancer. Moreover, using reporter gene assay, we demonstrated that they can both activate this enhancer. With supervised and unsupervised approaches, we were able to determine FUBP1 and RUNX1 binding motifs that are functionally important for the enhancer activation. Finally, we demonstrated that FUBP1 overexpression in a pre-B cell line increases the expression of KIT protein and exacerbates one of the KIT downstream pathways. FUBP1 overexpression increases also cell proliferation by promoting cell cycle progression in vitro . Concordantly, in vivo, xenografted immunodeficient mice injected with overexpressed FUBP1 cells present a shorter survival time than control mice.To conclude, we demonstrate a regulatory network involving RUNX1 and FUBP1 for the control of a KIT enhancer. Indeed, FUBP1 and RUNX1 can colocalize on chromatin, regulate KIT transcription by binding to a common region in a KIT enhancer, and promote cell cycle progression. These findings suggest a new mechanism for the control of the proliferation of pre-B lymphoblasts. Because FUBP1 and KIT are overexpressed in some types of leukemia, abnormalities in this regulatory network could participate in the onset or the maintenance of RUNX1-related leukemia.This work is supported by Ligue Régionale Contre le Cancer, Région Bretagne, Rennes Métropole, French Research Ministry, Société Française de lutte contre les Cancers et les leucémies de l'Enfant et de l'adolescent, Fédération Enfants et Santé, Société Française de Biochimie et Biologie Moléculaire, Société Française d'Hématologie, Mrs. M-Dominique Blanc-Bert and the Marie Curie Actions of the European Union FP7 under REA grant agreement n°291851. DisclosuresNo relevant conflicts of interest to declare.

MYC in T-cell acute lymphoblastic leukemia: functional implications and targeted strategies.

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological cancer that frequently occurs in children and adolescents, which results from the transformation of immature T-cell progenitors. Aberrant cell growth and proliferation of T-ALL lymphoblasts are sustained by activation of strong oncogenic drivers. Mounting evidence highlights the critical role of the NOTCH1-MYC highway toward the initiation and progression of T-ALL. MYC has been emphasized as a primary NOTCH1 transcriptional target impinging in leukemia-initiating cell activity particularly responsible for disease onset and relapse. These findings lay a foundation of T-ALL as an ideal disease model for studying MYC-mediated cancer. The biology of MYC deregulation in T-ALL supports innovative strategies for therapeutic targeting of MYC. To summarize the relevant literature and data in recent years, we here provide a comprehensive overview of the functional importance of MYC in T-ALL development, and the molecular mechanisms underlying MYC deregulation in T-ALL. Finally, we illustrate the innovative MYC-targeted approaches that have been evaluated in pre-clinical models and shown significant efficacy. Given the complexity of T-ALL molecular pathogenesis, we propose that a combination of anti-MYC strategies with conventional chemotherapies or other targeted/immunotherapies may provide the most durable response, especially for those patients with relapsed and refractory T-ALL.

The Association of PRKRAP1 Pseudogene with Acute Lymphoblastic Leukemia Risk

Acute Lymphoblastic Leukemia (ALL) consists of excessive proliferation of lymphoblasts. The frequency of Human Leukocyte Antigen (HLA)-DR53 (DRB4) homozygosity and allele was found to be higher in male childhood ALL cases. The aim of this study was to identify the HLA-DR53 allele frequency; interferon-inducing double chain ribonucleic acid binding protein kinase A pseudogene 1 (PRKRAP1) positivity; rs2395185 allele and genotype frequencies in ALL patients.

Effects of N‐oleoylethanolamide on Lymphoblasts Deficient in Tafazzin

Barth Syndrome (BTHS) is a rare X-linked genetic disorder caused by mutations in the TAZ gene that encodes for the cardiolipin remodelling enzyme, Tafazzin. This syndrome is characterized by cardiac and skeletal myopathies, as well as immunological deficits that cause significant morbidity and mortality. Study of the molecular pathology of BTHS thus provides insight into the role of cardiolipin and mitochondria in cellular physiology, while addressing a clinically relevant disease. Current treatment options for BTHS are limited, but a recent trial suggests that PPARα activation may be therapeutic. The objective of this study was to quantitatively examine the growth properties and mitochondrial physiology of B-lymphoblasts derived from five donors with BTHS, as well as effects of treatment with oleoylethanolamide (OEA), a bioactive N-acylethanolamine. Cyclic neutropenia is a well-recognized aspect of the pathology of BTHS. We hypothesized that deficits in lymphoblast proliferation would also be evident, and that OEA, which activates receptors including PPARα, would demonstrate therapeutic benefit. One million B-lymphoblasts derived from BTHS donors and age- and sex-matched healthy controls were seeded on day 0 and counted daily for 4 days. On day 4, there were 27.7 ± 4.6% fewer BTHS B-lymphoblasts than control cells (P<0.05), indicating that lymphopenia is likely also a component of BTHS. Treatment of B-lymphoblasts with 1 μM OEA caused no significant effect on control cell numbers, but significantly improved deficits in each of the five BTHS lymphoblast lines, raising the mean cell number on day 4 from 3.74 × 106 to 4.25 × 106 cells, although a full rescue of growth was not achieved. Analysis of electron micrographs of samples from two distinct BTHS B-lymphoblast donors indicated that cells had larger mitochondria as compared with healthy controls (mean of 0.67 ± 0.07 µM2 versus 0.27 ± 0.16 µM2, respectively). OEA decreased mitochondrial size by 53.0 ± 10.9%, while increasing the total mitochondrial number per cell by 92.6 ± 58.6%. OEA reduced the elevated expression of the enzyme CDS1 in BTHS B-lymphoblasts to healthy control levels, suggesting improved cardiolipin levels may play a role. However, an initial donor pair comparison did not show an effect of OEA on cardiolipin content, suggesting other mechanisms should be explored. Higher immunodetectable levels of OPA1, a biomarker of mitochondrial fusion, were found in lymphoblasts from children with BTHS, and were attenuated by OEA. Results from this study newly identify lymphopenia as a probable immunological deficit in BTHS, and suggest that therapies targeting aberrant fission/fusion of the mitochondrial network, rather than cardiolipin content, per se, and may have clinical utility for treatment of this disease.

ALL-394: Hyper-CVAD vs. BFM-Like Regimens in Adult Patients with Philadelphia-Negative Acute Lymphoblastic Leukemia: A Single-Center Experience

Context Acute lymphoblastic leukemia (ALL) is a heterogeneous group of diseases characterized by clonal proliferation of lymphoblasts. Improvement in the outcome of ALL in adult patients still has unfulfilled needs. Objective This study was conducted to compare outcome of the polychemotherapy regimens BFM-like chemotherapy and hyperCVAD in adult ALL patients. Design Retrospective study applied to 77 adult ALL patients who were diagnosed between 2011 and January 2019. Setting The study was conducted at Oncology Center Mansoura University. Patients or other participants Study applied to 77 adult Philadelphia-negative ALL patients: 49 (63.6%) patients were male and 28 (36.4%) patients were female, with a mean age of 28 years (range: 16–60). Interventions The study consisted of 2 arms for polychemotherapy regimens; BFM-like and hyper-CVAD. Main outcome measures Complete response (CR) rate and overall survival (OS). Results Among the 77 patients that were included, 48 patients (62.3%) had B-cell ALL, and 29 patients (37.7%) had T-cell ALL. Fifty-one patients (66.2%) were treated by BFM-like chemotherapy, and 26 patients (33.8%) were treated by hyper-CVAD. Complete remission rate was 90.2% and 73.1% in BFM-like chemotherapy and hyper-CVAD, respectively (p=0.05). There was no statistically significant difference in relapse rate between both regimens. Both regimens were comparable regarding different toxicities, ICU admission rate, and therapy-related deaths. Patients who received BFM-like chemotherapy showed a significant OS than who received hyper-CVAD (median; 28 vs. 12 month p=0.008). Moreover, in subset analysis; younger patients ( Conclusions A BFM-like regimen appears to be appropriate for young adult patients with ALL. Both BFM-like regimen and hyper CVAD seem to be equally safe and effective in adult patients ≥ 30 years.

BCR-ABL1-like B-lymphoblastic leukemia/lymphoma: Review of the entity and detection methodologies.

BCR-ABL1-like B-lymphoblastic leukemia/lymphoma (BCR-ABL1-like ALL or Ph-like ALL) is a neoplastic proliferation of lymphoblasts that has a gene expression profile similar to that of B-ALL with t(9;22)(q34.1;q11.2) BCR-ABL1, but lacks that gene fusion. It is associated with poor prognosis and is seen in 10%-20% of pediatric cases and 20%-30% of adult cases of ALL. It is included as a provisional entity in the revised 4th edition of the WHO Classification. A variety of different genetic abnormalities are identified in this entity, but they all converge on pathways that are potentially responsive to the addition of targeted therapy to conventional chemotherapy. Thus, it is important to screen for BCR-ABL1-like ALL, particularly in adults and pediatric patients with high-risk clinical features. Here, we provide a brief overview of the genetic profile and clinical features of BCR-ABL1-like ALL and review laboratory methodologies for routine identification of this genetically heterogeneous entity.

Potential of &amp;lt;i&amp;gt;Syzygium aromaticum&amp;lt;/i&amp;gt; (Clove) Leaf Extract on Immune Proliferation Response in Balb/c Mice Infected with &amp;lt;i&amp;gt;Salmonella typhimurium&amp;lt;/i&amp;gt;

Background and Objective: Syzygium aromaticum is an immunomodulator with the main active compound eugenol which can stimulate the function of lymphocyte proliferation and macrophage production. Lymphocytes play an important role for body protection against infection. This study aims to analyze the effect of S. aromaticum extract to increase proliferation of lymphocytes, lymphoblasts and macrophage production in Balb/c mice infected with Salmonella typhimurium. Methodology: Mice strain Balb/c were divided into 4 groups: treatment group infected with S. typhimurium and control group (without treatment) to tested the activity of peritoneal macrophages. The treatment group was administrated by S. aromaticum leaf extract (15 mg, 75 mg, 150 mg/kgbw) for 12 days. Results: S. aromaticum leaf extract increased the proliferation activity (p < 0.001) at dose of 15, 75, and 150 mg/kgbw, increased lymphocytes at dose 150 mg/kgbw (p < 0.05), increased the activity of macrophage ROI secretion at dose of 150 mg/kgbw (p < 0.05), and increased in lymphoblast (p < 0.05). Conclusion: Administration of S. aromaticum leaf extract increased the proliferation activity of lymphocytes, lymphoblasts and ROI secretion of macrophagesin Balb/c mice infected with S. typhimurium.

Paclitaxel induces Stathmin 1 phosphorylation, microtubule stability and apoptosis in acute lymphoblastic leukemia cells.

Acute lymphoblastic leukemia (ALL) is a hematological malignancy characterized by abnormal proliferation and accumulation of lymphoblasts in the hematopoietic system. Stathmin 1 is a proliferation marker for normal lymphocytes, which has been described as highly expressed in ALL patients and functionally important for leukemia phenotype. In the present study, we expand our previous observations and aim to investigate Stathmin 1 expression and its impact on laboratory features and clinical outcomes in an independent cohort of ALL patients, and to verify the effects of paclitaxel treatment on Stathmin 1 phosphorylation and cell viability in ALL cell lines. In ALL patients, Stathmin 1 expression was significantly increased, associated with lower age onset and positively correlated with white blood cell counts, but did not impact on clinical outcomes. Functional assays revealed that paclitaxel induces Stathmin 1 phosphorylation at serine 16 (an inhibitory site), microtubule stability and apoptosis in Jurkat and Namalwa cell lines. Paclitaxel treatment did not modulate cell viability of normal peripheral blood leukocytes. In conclusion, our data confirm increased levels of Stathmin 1 in ALL patients and that therapeutic doses of paclitaxel inhibits Stathmin 1 function and promote microtubule stability and apoptosis in ALL cells.

Two hematopoietic transcription factors, RUNX1 and FUBP1, control the expression of KIT oncogene in pre-B lymphoblasts

Abstract Hematopoiesis involves an elaborate network of transcription factors articulated with transcriptional cooperators. RUNX1 geneencodes a transcription factor playing a key role in hematopoiesis. Abnormal functions of RUNX1 protein are implicated in blood cancer, notably in pediatric B-cell precursor acute lymphoblastic leukemia (BCP-ALL). To unravel the mechanisms behind the modulation of the transcriptional activity of RUNX1, we performed experiments of RUNX1-specific chromatin immunoprecipitation (ChIP) followed by mass spectrometry, and identified Far Upstream Element Binding Protein 1 (FUBP1) as a potential functional cooperator of RUNX1. The helicase and transcriptional regulator FUBP1 has recently been described to be essential for expansion and self-renewal of hematopoietic stem cells and to function as a potential cancer driver gene in lymphoblastic leukemia. Our goals were to validate the protein interaction between RUNX1 and its putative cooperator FUBP1, to identify gene(s) transcriptionally controlled by both RUNX1 and FUBP1, and finally to demonstrate the biological consequence of the cooperation between RUNX1 and its cooperator FUBP1. Co-immunoprecipitation and colocalization experiments demonstrate that RUNX1 colocalizes with FUBP1 in pre-B cell lines, in pre-B lymphoblasts isolated from BCP-ALL patients, and more generally in other hematopoietic progenitors. To characterize some target genes directly regulated by FUBP1 and RUNX1, we performed ChIP combined with sequencing (ChIP-seq) for FUBP1 and RUNX1. Those binding signals were compared to different histone marks and reveal that a subset of FUBP1 and RUNX1 binding signals are enriched within primed enhancer regions characterized by histone H3K4me1 marks. Our data show that RUNX1 signal is also enriched within FUBP1 regions, demonstrating that they are often retrieved on same chromatin regions, bound by FUBP1. Interestingly, FUBP1 is widely distributed in the genome, therefore only a subset of RUNX1 binding signals overlaps with FUBP1 binding signals. To go further, using qPCR, we investigated the expression level of several potential target candidate genes in pre-B cells overexpressed for FUBP1 or RUNX1. We found that both FUBP1 and RUNX1 positively regulate KIT transcript. KIT is a tyrosine kinase receptor expressed on hematopoietic progenitors cell surface and is an oncogene overexpressed notably in different types of leukemia. With the comparison of data from FUBP1 and RUNX1 ChiP-seq, we found that FUBP1 and RUNX1 share two common DNA binding regions on KIT gene, including one overlapping with histone H3K4me1 mark. ChIP-qPCR analyses confirm the binding of FUBP1 and RUNX1 on the KIT enhancer. Moreover, using reporter gene assay, we demonstrated that they can both activate this enhancer. With supervised and unsupervised approaches, we were able to determine FUBP1 and RUNX1 binding motifs that are functionally important for the enhancer activation. Finally, we demonstrated that FUBP1 overexpression in a pre-B cell line increases the expression of KIT protein and exacerbates one of the KIT downstream pathways. FUBP1 overexpression increases also cell proliferation by promoting cell cycle progression in vitro . Concordantly, in vivo, xenografted immunodeficient mice injected with overexpressed FUBP1 cells present a shorter survival time than control mice. To conclude, we demonstrate a regulatory network involving RUNX1 and FUBP1 for the control of a KIT enhancer. Indeed, FUBP1 and RUNX1 can colocalize on chromatin, regulate KIT transcription by binding to a common region in a KIT enhancer, and promote cell cycle progression. These findings suggest a new mechanism for the control of the proliferation of pre-B lymphoblasts. Because FUBP1 and KIT are overexpressed in some types of leukemia, abnormalities in this regulatory network could participate in the onset or the maintenance of RUNX1-related leukemia. This work is supported by Ligue Regionale Contre le Cancer, Region Bretagne, Rennes Metropole, French Research Ministry, Societe Francaise de lutte contre les Cancers et les leucemies de l'Enfant et de l'adolescent, Federation Enfants et Sante, Societe Francaise de Biochimie et Biologie Moleculaire, Societe Francaise d'Hematologie, Mrs. M-Dominique Blanc-Bert and the Marie Curie Actions of the European Union FP7 under REA grant agreement n°291851. Disclosures No relevant conflicts of interest to declare.

Multiple Osteolytic Lesions Causing Hypercalcemia: A Rare Presentation of Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia is characterized by unchecked proliferation of malignant lymphoblasts which replaces the normal bone marrow culminating in anemia due to red blood cells inadequacy as well as in easy bruising/bleeding secondary to insufficient platelets production. Even the white blood cells which are produced excessively are immature and abnormal. ALL is the most common hematological malignancy in children. Most commonly, patients present with lymphadenopathy, recurrent infections, bleeding, fatigue, and bone pains. Bone pains, often particularly involving long bones, occur in about 21–38% of cases and are due to overcrowding of bone marrow with malignant cells. Vast majority of children with ALL have thrombocytopenia and/or anemia with a normal or mildly elevated white blood cells count with the presence of lymphoblasts on peripheral smear. About 50% of children present with bleeding while about 75% of patients have platelet count 100,000/microL. Visceromegaly is not uncommon but osteolytic lesions and hypercalcemia are rather uncommon. We present a 22-year-old gentleman with generalized fatigue and bone pains without visceromegaly. There was severe hypercalcemia with normal parathyroid levels but multiple osteolytic lesions. Peripheral smear showed anemia without blasts, whereas a bone marrow biopsy revealed > 30% blasts with interspersed CD 10 positive cells.

Subchronic exposure to deoxynivalenol exerts slight effect on the immune system and liver morphology of growing rabbits

As the most common grain contaminant worldwide, deoxynivalenol is of high importance despite its low toxicity compared to other trichothecene mycotoxins. Data on the effects of deoxynivalenol in rabbits are scarce. Thus, the aim of this study was to investigate the effects of dietary deoxynivalenol fed at a high level (10 mg/kg of feed) on the productive performance, blood indices, immunological variables, histopathological changes, and genotoxicity in rabbits. Forty-eight Pannon White rabbits were exposed to contaminated diets for three weeks. Despite its high concentration, deoxynivalenol did not affect the feed intake, body weight, and body weight gain. Liver and kidney function was not affected, as shown by the clinical chemistry indices. Conversely, in two rabbits the toxin caused mild fibrosis of the liver, without degenerative changes of the hepatocytes. No genotoxicity could be observed either. Gut cytokines and the phagocytic activity of the macrophages did not differ significantly. The percentage of neutrophils was significantly lower, whereas that of eosinophils was significantly higher in the toxin-fed group. Deoxynivalenol did not cause significant changes in gut and villus morphology. In 4 out of the 6 deoxynivalenol-treated animals, the ratio of lymphoblast proliferation and simultaneous apoptosis shifted towards apoptosis in the gut-associated lymphoid tissue. In the central part of the lymphoid follicles of the spleen, lymphocyte depletion and follicular atrophy could be detected. It can be concluded that rabbits are less sensitive to deoxynivalenol, but the findings confirm that this Fusarium toxin is capable of modulating the immune response.

Epstein–Barr virus super-enhancer eRNAs are essential for MYC oncogene expression and lymphoblast proliferation

Epstein-Barr virus (EBV) super-enhancers (ESEs) are essential for lymphoblastoid cell (LCL) growth and survival. Reanalyses of LCL global run-on sequencing (Gro-seq) data found abundant enhancer RNAs (eRNAs) being transcribed at ESEs. Inactivation of ESE components, EBV nuclear antigen 2 (EBNA2) and bromodomain-containing protein 4 (BRD4), significantly decreased eRNAs at ESEs -428 and -525 kb upstream of the MYC oncogene transcription start site (TSS). shRNA knockdown of the MYC -428 and -525 ESE eRNA caused LCL growth arrest and reduced cell growth. Furthermore, MYC ESE eRNA knockdown also significantly reduced MYC expression, ESE H3K27ac signals, and MYC ESEs looping to MYC TSS. These data indicate that ESE eRNAs strongly affect cell gene expression and enable LCL growth.

Site-Specific Phosphorylation of Ikaros Induced by Low-Dose Ionizing Radiation Regulates Cell Cycle Progression of B Lymphoblast Through CK2 and AKT Activation

To determine how low-dose ionizing radiation (LDIR) regulates B lympho-proliferation and its molecular mechanism related with Ikaros, transcription factor. Splenocytes and IM-9 cells were uniformly irradiated with various doses of a (137)Cs γ-source, and cell proliferation was analyzed. To determine the LDIR-specific phosphorylation of Ikaros, immunoprecipitation and Western blot analysis were performed. To investigate the physiologic function of LDIR-mediatied Ikaros phosphorylation, Ikaros mutants at phosphorylation sites were generated, and cell cycle analysis was performed. First, we found that LDIR enhances B lymphoblast proliferation in an Ikaros-dependent manner. Moreover, we found that LDIR elevates the phosphorylation level of Ikaros protein. Interestingly, we showed that CK2 and AKT are involved in LDIR-induced Ikaros phosphorylation and capable of regulating DNA binding activity of Ikaros via specific phosphorylation. Finally, we identified LDIR-specific Ikaros phosphorylation sites at S391/S393 and showed that the Ikaros phosphorylations at these sites control Ikaros's ability to regulate G1/S cell cycle progression. Low-dose ionizing radiation specifically phosphorylates Ikaros protein at Ser 391/393 residues to regulate cell cycle progression in B lymphoblast.