pre-B Cell Acute Lymphoblastic Leukemia Research Articles

Abstract 5117: CK2 inhibiton exhibits synergistic effect in acute lymphoblastic leukemia

Abstract Survival for pre-B cell Acute lymphoblastic leukemia (B ALL) has improved greatly, however. High risk (HR) subgroups continue to result in significant mortality and morbidity of pediatric oncology patients. Pediatric T-cell acute lymphoblastic leukemia (T-ALL) is a lethal disease, often associated with high-risk clinical features. T-ALL therapy has made less improvement than B ALL and continues to represent a significant number of high-risk outcomes. Novel treatment strategies are required to overcome chemotherapy resistance and improve morbidity for HR B ALL. The development of treatments that can overcome chemotherapy resistance is essential for improving survival in T-ALL. Deletions of IKZF1, resulting in decreased IKAROS function, are present in High-risk ALL patients. Casein kinase 2 (CK2), a protein kinase upregulated in ALL, phosphorylates IKAROS preventing DNA binding reducing transcriptional regulation in ALL patients. Past studies have shown that pharmacologic inhibition of CK2 with CX-4945 rescues IKAROS function as a transcriptional regulator. Receptor tyrosine kinase c-KIT is transcriptionally regulated by IKAROS and is often upregulated in cancer. The purpose of this study was to determine whether restoration of IKAROS via CX-4945 would act in a synergistic manner with c-KIT inhibitor imatinib in ALL.Methods/results B-ALL Nalm6 cells were treated with imatinib over 72-hours to establish the half-maximal inhibitory concentration (IC50). The IC50 was used to determine the concentration range of imatinib to be used in combination with CX-4945 in a 72-hour synergy analysis of cytotoxicity.. Cell viability was measured using WST-1 cell proliferation assay. The data were analyzed using Calcusyn and synergy was defined as a combination index below 0.85. The study was repeated to determine a more precise range of synergy. The cytotoxicity of single drug c-KIT inhibitor, Imatinib, in Nalm6 B-ALL yielded an IC50 of 25uM while CK2 inhibitor CX-4945 resulted in 4uM. When a combination was administered with a constant dose of CX-4945 at 4uM and varying concentrations of imatinib, synergy was observed at multiple dose combinations. Conclusion: The data shows that CK2 inhibitor, CX-4945, and c-KIT inhibitor, imatinib, exhibit a synergistic therapeutic effect. Imatinib is indicated for use in Philadelphia positive (Ph+) acute lymphoblastic leukemia so future studies will include testing CX-4945/imatinib synergy in Ph+ BALL where we expect to see more potent synergistic effect. Citation Format: Daniel Gary Bogush, Joseph Schramm, Katarina Dovat, Yali Ding, Chingakham Singh, Sinisa Dovat. CK2 inhibiton exhibits synergistic effect in acute lymphoblastic leukemia [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 5117.

Targeting TNF/IL-17/MAPK pathway in hE2A-PBX1 leukemia: effects of OUL35, KJ-Pyr-9, and CID44216842.

t(1;19)(q23;p13) is one of the most common translocation genes in childhood acute lymphoblastic leukemia (ALL) and is also present in acute myeloid leukemia (AML) and mixed-phenotype acute leukemia (MPAL). This translocation results in the formation of the oncogenic E2A-PBX1 fusion protein, which contains a trans-activating domain from E2A and a DNA-binding homologous domain from PBX1. Despite its clear oncogenic potential, the pathogenesis of E2A-PBX1 fusion protein is not fully understood (especially in leukemias other than ALL), and effective targeted clinical therapies have not been developed. To address this, we established a stable and heritable zebrafish line expressing human E2A-PBX1 (hE2APBX1) for high-throughput drug screening. Blood phenotype analysis showed that hE2APBX1 expression induced myeloid hyperplasia by increasing myeloid differentiation propensity of hematopoietic stem cells (HSPCs) and myeloid proliferation in larvae, and progressed to AML in adults. Mechanistic studies revealed that hE2A-PBX1 activated the TNF/IL-17/MAPK signaling pathway in blood cells and induced myeloid hyperplasia by upregulating the expression of the runx1. Interestingly, through high-throughput drug screening, three small molecules targeting the TNF/IL-17/MAPK signaling pathway were identified, including OUL35, KJ-Pyr-9, and CID44216842, which not only alleviated the hE2A-PBX1- induced myeloid hyperplasia in zebrafish but also inhibited the growth and oncogenicity of human pre-B ALL cells with E2A-PBX1. Overall, this study provides a novel hE2A-PBX1 transgenic zebrafish leukemia model and identifies potential targeted therapeutic drugs, which may offer new insights into the treatment of E2A-PBX1 leukemia.

Combinatorial targeting of telomerase and DNA-PK induces synergistic apoptotic effects against Pre-B acute lymphoblastic leukemia cells.

Due to the high demand for novel approaches for leukemia-targeted therapy, this study investigates the impact of DNA-PK inhibitor NU7441 on the sensitivity of pre-B ALL cells to the telomerase inhibitor MST-312. The study involved NALM-6 cells treated with MST-312 and NU7441, assessing their viability and metabolic activity using trypan blue and MTT assays. The study also evaluated apoptosis, gene expression changes, and DNA damage using flow cytometry, qRT-PCR, and micronucleus assays. The binding energy of MST-312 in the active site of telomerase was calculated using molecular docking. The study's findings revealed a synergistic decline in both cell viability and metabolic activity in NALM-6 cells when exposed to the combined treatment of MST-312 and NU7441, and this decrease occurred without any adverse effects on healthy PBMC cells. Furthermore, the combination treatment exhibited a significantly higher induction of apoptosis than treatment with MST-312 alone, as observed through flow cytometry assay. qRT-PCR analysis revealed that this enhanced apoptosis was associated with a notable downregulation of Bcl-2 expression and an upregulation of Bax gene expression. Moreover, the combination therapy decreased expression levels of hTERT and c-Myc genes. The micronucleus assay indicated that the combination treatment increased DNA damage in NALM-6 cells. Also, a good conformation between MST-312 and the active site of telomerase was revealed by docking data. The study suggests that simultaneous inhibition of telomerase and DNA-PK in pre-B ALL presents a novel targeted therapy approach.

Chemotherapeutic metabolism presenting as a recalcitrant case of hand-foot syndrome and mucositis.

Mercaptopurine (6MP) and methotrexate (MTX) are commonly used for maintenance chemotherapy for acute lymphoblastic leukemia (ALL). These medications have been associated with various side effects such as myelosuppression, colitis, and thyroiditis in addition to numerous cutaneous adverse events. Cutaneous side-effects most reported include mucositis, alopecia, xerosis, and pruritus. We report an interesting case of hand-foot syndrome to 6MP in a child on maintenance therapy for B-cell ALL from an alteration in medication metabolism. We report a 10-year-old male on maintenance chemotherapy for pre-Bcell ALL who presented to the hospital with worsening oral lesions and erythematous, fissured plaques on the palms and soles. Maintenance therapy consisted of IV vincristine and 5-day pulse of steroids every 12 weeks, daily 6MP, and weekly MTX, which were increased to ≥ 150% of standard dosing due to persistent absolute neutrophil counts > 1500. Metabolites obtained on admission demonstrated elevated 6MMP metabolites at 35,761 (normal < 5700). TPMT and NUDT15 enzyme activity were normal and no alterations in genotyping were discovered. Patient's oral chemotherapy, including both 6MP and MTX, were stopped and allopurinol 100 mg daily was initiated, which lead to overall improvement. Clinical findings of acute mucositis and worsening of hand-foot syndrome, in the setting of inadequate myelosuppression in a child on maintenance therapy for ALL should raise concerns to consider altered metabolism pathway leading to toxic metabolite buildup. Allopurinol can play in improving cutaneous manifestation and chemotherapeutic dosing in patients with altered metabolism.

Presence of Enteric Fever with Unusual Clinical Scenarios: A Case Series

Salmonella species are associated with bacteraemia, diarrhoea, as well as focal infections. Salmonella Typhi is the most pathogenic species. Salmonella Paratyphi B commonly affects immunocompromised hosts. The present case series showcases six cases of infection caused by typhoidal Salmonellae with unusual clinical scenarios. The first case report explains a case of neonatal meningitis where the causative agent was S. Paratyphi B. A case of lumbar spondylodiscitis is also reported where the aetiology was found to be Salmonella Typhi. Case three reports S. Typhi infection in a patient with Pre-B cell Acute Lymphoblastic Leukemia (ALL). S. Paratyphi B was isolated from a blood culture of a patient on haemodialysis and also from ascitic fluid from a case of Chronic Liver Disease (CLD). S. Typhi was isolated from the pleural fluid of a patient with carcinoma of the prostate.

24 Adaptive Functioning and Academic Achievement in Survivors of Childhood Acute Lymphoblastic Leukemia

Objective:Executive functioning (EF) and socioeconomic status (SES) are associated with functional outcomes (adaptive functioning and academic achievement) in healthy controls and pediatric populations with executive dysfunction. However, these relationships have yet to be investigated in survivors of childhood acute lymphoblastic leukemia (ALL), a population with EF impairment resulting from disease and treatment characteristics. The objective of this study was to examine the associations of functional outcomes with EF and SES (neighborhood-specific variables and academic support) in survivors of childhood ALL.Participants and Methods:Forty-four participants (38.6% female, 72.7% non-Hispanic White, ages 6-17) previously diagnosed with low-risk or standard-risk pre-B cell ALL and treated with chemotherapy-only were included. Participants were evaluated on performance-based measures of EF (cognitive flexibility, verbal fluency, working memory, and processing speed) and academic achievement (word reading and math calculation), and parent-ratings of EF and adaptive functioning. All measures were expressed as T-scores with lower scores indicating better performance. Neighborhood-specific variables were based on participants’ zip codes and census block group, and included area deprivation index (ADI) and child opportunity index (COI). Lower ADI and COI indicate lesser deprivation and greater opportunity. Individualized education plan (IEP) status was used as a proxy of academic support, coded dichotomously as with or without IEP. Percentages of participants showing impairments in functional outcomes were calculated using a cutoff of &gt; 1 SD above the normative mean. Partial correlations were conducted while controlling for age at evaluation, age at diagnosis, sex, and verbal IQ, to examine whether participants with poorer performance-based and parent-rated EF would show reduced functional outcomes. Multiple regression analyses were conducted to evaluate whether neighborhood-specific variables and IEP status would predict functional outcomes while controlling for covariates.Results:Compared to population norms, survivors of childhood ALL showed worse functional outcomes. Within adaptive functioning, 45.5% of participants showed impairment in activities of daily living and leadership. Adaptive functioning was significantly positively correlated with parent-rated, but not performance-based, EF (r=0.694, p&lt;0.001). Compared to female survivors, male survivors were at increased risk for adaptive functioning difficulties (r=-0.401, p&lt;0.05). Impairments for word reading and math calculation were 25% and 41.7%, respectively. Greater math calculation was associated with better verbal fluency (r=0.378, p&lt;0.05) and processing speed (r=0.439, p&lt;0.05). Older participants at evaluation (/3=-0.580, p&lt;0.001) and those without IEP support (ß=0.465, p&lt;0.05) showed better word reading. Lower ADI predicted better verbal fluency (ß=0.282, p=0.041), however, neighborhood-specific variables were not associated with functional outcomes.Conclusions:Prior findings indicate that performance-based measures and parent-ratings assess different constructs of EF. Thus, adaptive functioning may relate more to the behavioral construct of EF than its cognitive construct. Current findings also suggest that male survivors are at increased risk for reduced adaptive functioning, consistent with recent reports that male survivors of ALL are at greater risk for specific neurocognitive outcomes. Overall, functional outcomes may be more strongly related to EF than neighborhood-specific variables. Long-term goals include early screening of adaptive and academic difficulties, targeted intervention, and neuropsychological monitoring to support pediatric survivors’ neurocognitive and psychosocial development.

NKG2A discriminates natural killer cells with a suppressed phenotype in pediatric acute leukemia.

Natural killer (NK) cells are important for early tumor immune surveillance. In patients with hematological cancers, NK cells are generally functional deficient and display dysregulations in their receptor repertoires. Acute leukemia is the most common cancer in children, and we here performed a comparative phenotypic profiling of NK cells from B-cell precursor acute lymphoblastic leukemia (BCP-ALL) patients to identify aberrant NK cell phenotypes. NK cell phenotypes, maturation, and function were analyzed in matched bone marrow and blood NK cells from BCP-ALL patients at diagnosis, during treatment, and at end of treatment and compared with age-matched pediatric control subjects. Expression of several markers were skewed in patients, but with large interindividual variations. Undertaking a multiparameter approach, we found that high expression levels of NKG2A was the single predominant marker distinguishing NK cells in BCP-ALL patients compared with healthy control subjects. Moreover, naïve CD57-NKG2A NK cells dominated in BCP-ALL patients at diagnosis. Further, we found dysregulated expression of the activating receptor DNAM-1 in resident bone marrow CXCR6+ NK cells. CXCR6+ NK cells lacking DNAM-1 expressed NKG2A and had a tendency for lower degranulation activity. In conclusion, high expression of NKG2A dominates NK cell phenotypes from pediatric BCP-ALL patients, indicating that NKG2A could be targeted in therapies for this patient group.

Drivers of Differential Time to Diagnosis in Pediatric ALL Tied to Race and Ethnicity.

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, with diagnosis preceded by symptoms that may include fever, weight loss, fatigue, bleeding, and bruising. Timely diagnosis and treatment of ALL may lead to improved outcomes and reduced morbidity from associated complications, including tumor lysis syndrome, hyperviscosity, and stroke. We performed a retrospective cohort analysis of 274 pediatric pre-B cell ALL and acute lymphoblastic lymphoma patients within Montefiore Health System to determine whether there were factors associated with time from symptom onset to diagnosis. The median time to diagnosis for all patients was 11.5 days (interquartile range: 7.8, 14.3). Those with Medicaid insurance (n=189) were diagnosed sooner than those with private/self-pay insurance (n=85) (median of 10 vs. 16 days; P =0.05). English and other language speakers experienced fewer median days from symptom onset to diagnosis date compared with Spanish speakers (11 vs. 7 vs. 14; P =0.05). Insurance status may impact the time to diagnosis to a greater degree in non-Hispanic patients, while the English language and female sex may represent a greater advantage to Hispanic patients. Insurance status and language preference may impact the time to diagnosis of pediatric ALL. There is a further need to confirm our findings and to study possible causes driving these disparities.

Transcriptional signatures associated with persisting CD19 CAR-T cells in children with leukemia

In the context of relapsed and refractory childhood pre-B cell acute lymphoblastic leukemia (R/R B-ALL), CD19-targeting chimeric antigen receptor (CAR)-T cells often induce durable remissions, which requires the persistence of CAR-T cells. In this study, we systematically analyzed CD19 CAR-T cells of 10 children with R/R B-ALL enrolled in the CARPALL trial via high-throughput single-cell gene expression and T cell receptor sequencing of infusion products and serial blood and bone marrow samples up to 5 years after infusion. We show that long-lived CAR-T cells developed a CD4/CD8 double-negative phenotype with an exhausted-like memory state and distinct transcriptional signature. This persistence signature was dominant among circulating CAR-T cells in all children with a long-lived treatment response for which sequencing data were sufficient (4/4, 100%). The signature was also present across T cell subsets and clonotypes, indicating that persisting CAR-T cells converge transcriptionally. This persistence signature was also detected in two adult patients with chronic lymphocytic leukemia with decade-long remissions who received a different CD19 CAR-T cell product. Examination of single T cell transcriptomes from a wide range of healthy and diseased tissues across children and adults indicated that the persistence signature may be specific to long-lived CAR-T cells. These findings raise the possibility that a universal transcriptional signature of clinically effective, persistent CD19 CAR-T cells exists.

A novel tumor-bearing humanized mouse model for evaluating the efficacy and predictive safety of bispecific T cell engager

Abstract Bispecific T cell engager (BiTE) is one of the most promising therapeutic approaches for treatment of various malignancies. Humanized mice engrafted with human peripheral blood mononuclear cells (PBMCs) have currently become the preclinical platform for evaluating the effectiveness of various cancer immunotherapies including BiTE. However, the wide application of this humanized animal model is limited by a strong xenoreaction of human T cells against the mouse tissues. In this study, we used humanized murine major histocompatibility class I and class II double knock-out NSG mice (referred to DKO) to evaluate the antitumor effect of BiTE. The DKO mice were implanted with human pre-B acute lymphoblastic leukemia cell line (Nalm6). Five days later, the mice were reconstituted with PBMCs. Following CD19xCD3 BiTE treatment whole-body tumor burden was quantified by a in vivo imaging system. Our data demonstrated that the mice developed consistent clinical signs of leukemia-related body weight loss and hind-limb paralysis within 4 weeks. With serial dose of CD19xCD3 BiTE treatment, the tumor cell growing was significantly suppressed. A lower incidence of hind-limb paralysis with prolonged survival were observed in BiTE-treated mice compared with controls. In addition, after treatment with CD19xCD3 BiTE, the humanized mice exhibited elevated serum levels of human IFN-γ, TNF-a, IL-6, IL-10, IL-2, and IL-4. The cytokine production was dose-dependent and associated with the increase of CD19xCD3 BiTE effectiveness. This tumor-bearing humanized model provides a promising preclinical platform for evaluating the efficacy, toxic cytokine release, and dosing requirements of any T cell-based immunotherapies for cancer treatment.

Synergistic Anti-Cancer Effects of Second-Generation Proteasome Inhibitor Carfilzomib with Doxorubicin and Dexamethasone Via p53-Mediated Apoptosis in Pre-B Acute Lymphoblastic Leukemia Cells

Background: The ubiquitin-proteasome system (UPS) plays a crucial role in regulating the levels and functions of a large number of proteins in the cell, which are important for cancer cell growth and survival. The proteasome is highly activated in B-cell precursor acute lymphoblastic leukemia (BCP-ALL), which is the most common malignancy in children. The attempt to inhibit proteasome as a therapeutic strategy has been successful for some malignancies.&#x0D; Materials and Methods: In this experimental study, human BCP-ALL cell lines NALM-6 and SUP-B15 were treated with carfilzomib with and without the chemotherapeutic agents. The XTT assay evaluated the viability of the cells. Cell cycle analysis and apoptosis assay were assessed by flow cytometry. RQ-PCR and western blotting evaluated the expression of pro-/anti-apoptotic signals. A drug combination study for synergistic or additive effects of carfilzomib with doxorubicin or dexamethasone was performed.&#x0D; Results: We observed that carfilzomib alone induced G2/M cell cycle arrest and caspase-dependent apoptosis in the human BCP-ALL cells (NALM-6 and SUP-B15). Gene and protein expression analysis indicated the upregulation of pro-apoptotic as well as downregulation of the cell survival and proliferative signals (P-value&lt;0.05). The synergy of carfilzomib with doxorubicin or dexamethasone was revealed in BCP-ALL cells.&#x0D; Conclusion: Our results indicated that proteasome inhibition induces p53-mediated apoptosis in BCP-ALL cells. Since carfilzomib has a synergistic effect with anti-leukemic agents doxorubicin and dexamethasone in BCP-ALL cells, this combined-modality approach might be befitting for patients who do not respond well to conventional chemotherapy.

Mitotic recombinatory evolution in acute leukemia

A cohort of leukemia cases is presented with ancillary testing that includes microarray studies, karyotyping, FISH, and RNA sequencing to illustrate clonal evolution. Common evolution etiology with each case is apparent homologous mitotic recombination (HMR). The cohort includes: four cases of Pre B-cell acute lymphoblastic leukemia (B-ALL) with a single translocation derivative (19)t(1;19)(q23.3;p13.3), an acute myelogenous leukemia (AML) case with a paracentric inversion of 11q13.3q23 in both homologues confirmed as a rare KMT2A-MAML2 gene fusion, and a transplant patient in AML relapse with a t(6;11)(6q27;q23) and evolution to an additional derivative 6 chromosome. The PBX1-TCF3 fusion in the t(1;19) B-ALL subgroup has long been associated with clones that show either the balanced translocation (∼25%) or the unbalanced single derivative 19 (∼75%). Evidence from the CMAs and FISH is consistent with HMR initiating at either the PBX1 translocation breakpoint or at a more proximal long arm site that mediates the evolution to the unbalanced form. This is contrary to the previous assumptions of either nondisjunction duplication of the normal homologue with loss of the translocation derivative 1 or an original trisomy 1 that loses the translocation derivative 1. Relapse from an unrelated transplant donor created unique allele dosage ratios in the microarray of the AML patient with the t(6;11) KMT2A-AFDN fusion. An HMR-based evolution initiation site proximal to the 6q27 AFDN fusion gene is evident in the microarray of chromosome 6, the known oncogenic fusion derivative. The HMR selection driver in both AML cases is very likely associated with the DNA doubling of the oncogenic fusions in 6q and 11q, respectively. Since the oncogenic derivatives in the 1;19 cases are clearly the retained derivative 19, selection for the HMR clonal evolution in 1q is apparently based on the known proliferative advantage of extra copies of 1q in B-ALL and other malignancies. Although selection-based HMR can effectively initiate at any site proximal to a driver gene fusion, it appears that the translocation breaksite is common for many translocations. In addition, evidence from HMR evolution related distal 11q mutations, numerous unbalanced CCND1/IGH translocations, and the double MAML2/KMT2A presented in this study suggest that a recombinatorial "hot spot" exists near the CCND1 gene in many rearrangements or mutations within 11q.

Characterization of mesenchymal stem cells in pre-B acute lymphoblastic leukemia.

Components of the bone marrow microenvironment (BMM) have been shown to mediate the way in which leukemia develops, progresses and responds to treatment. Increasing evidence shows that leukemic cells hijack the BMM, altering its functioning and establishing leukemia-supportive interactions with stromal and immune cells. While previous work has highlighted functional defects in the mesenchymal stem cell (MSC) population from the BMM of acute leukemias, thorough characterization and molecular profiling of MSCs in pre-B cell acute lymphoblastic leukemia (B-ALL), the most common cancer in children, has not been conducted. Here, we investigated the cellular and transcriptome profiles of MSCs isolated from the BMM of an immunocompetent BCR-ABL1+ model of B-ALL. Leukemia-associated MSCs exhibited reduced self-renewal capacity in vitro and significant changes in numerous molecular signatures, including upregulation of inflammatory signaling pathways. Additionally, we found downregulation of genes involved in extracellular matrix organization and osteoblastogenesis in leukemia-associated MSCs. This study provides cellular and molecular insights into the role of MSCs during B-ALL progression.

Acute complications observed during intensive chemotherapy in pediatric patients with acute lymphoblastic leukemia: Single-center experience.

In childhood acute lymphoblastic leukemia (ALL), very promising results were obtained thanks to the developments in treatment strategies in recent years. However, acute complications during treatment continue to be the important causes of mortality and morbidity. In this study, acute complications that develop during the treatment of ALL in childhood were evaluated. Medical records of 47 patients treated according to (ALL Intercontinental Berlin-Frankfurt-Münster) 2009 protocol between 2016 and 2021 were evaluated retrospectively. Of 47 patients, 28 (59.6%) were male and 19 (40.4%) were female. The mean age at diagnosis was 5.9±4.2 years. Forty-four patients (93.6%) were pre-B cell ALL, 3 patients (6.4%) were pre-T cell ALL. Of 47 patients, 9 (19.1%) were high risk, 32 (68.1%) were intermediate risk, and 6 (12.8%) were standard risk. Acute complications developed in 38 patients (80.8%). Among these complications, infectious complications are the most common and these were followed by gastrointestinal complications, drug-related reactions, thrombotic, neurological, and endocrine/metabolic complications, respectively. In terms of complications that may develop, the threshold of suspicion should be kept low, and patients should be treated with the same medical team in fully equipped centers with a multidisciplinary approach. Inpatient treatment strategies should be applied especially in the early stages of treatment. The importance of inpatient treatment strategy, especially in the early stages of treatment, is emphasized.

Cytomegalovirus Reactivation in Patients With Acute Lymphoblastic Leukemia in Non-transplant Setting.

Acute lymphoblastic leukemia is predominately a childhood disease and around two third of cases are of B-cell phenotype. Cytomegalovirus is an important cause of morbidity and mortality in allogeneic hematopoietic progenitor cell transplant; however, it is rare in patients with B-cell acute lymphoblastic leukemia in non-transplant settings. In this study, we evaluated 72 patients of acute precursor (pre) B-cell acute lymphoblastic leukemia at Shaukat Khanum Memorial Cancer Hospital and Research Center, out of which three were positive for Cytomegalovirus.

Paediatric pre-B acute lymphoblastic leukaemia-derived exosomes regulate immune function in human T cells.

Exosomes derived from solid tumour cells are involved in immune suppression, angiogenesis and metastasis; however, the role of leukaemia‐derived exosomes has less been investigated. Hence, changes in immune response‐related genes and human T cells apoptosis co‐incubated with exosomes isolated from patients' pre‐B cell acute lymphoblastic leukaemia were evaluated in this in vitro study. Vein blood sample was obtained from each newly diagnosed acute lymphoblastic leukaemia (ALL) patient prior any therapy. ALL serum exosomes were isolated by ultrafiltration and characterized using Western blotting and transmission electron microscopy. Exosomes were then co‐incubated with T lymphocytes and the gene expressions, as well as functions of human T cells were quantified by qRT‐PCR. Apoptosis and caspase‐3 and caspase‐9 protein expression were also evaluated by flowcytometry and Western blotting analysis, respectively. Exosomes isolated from ALL patients affected T lymphocytes and elevated the apoptosis. Moreover, these exosomes altered the T cells profile into regulatory type by increasing the expression of FOXP3 and Tregs‐related cytokines, including TGF‐B and IL‐10. The expression level of Th17‐related transcription factors (RoRγt) and interleukins (IL‐17 and IL‐23) decreased after this treatment. According to our findings, exosomes derived from ALL patients' sera carry immunosuppressive molecules, indicating the possible effect of exosomes as liquid biomarkers for cancer staging.

COVID-19 Related Myositis in a Patient Recently Diagnosed with Pre B Cell Acute Lymphoblastic Leukemia

Myositis is not a common finding in patients diagnosed with COVID-19. Up to now, a few cases of COVID-19 associated with myositis have been reported.&#x0D; A 26-year-old man was referred to the hematology clinic due to leukocytosis and bicytopenia in his lab tests. The patient had no symptoms at the visit session. Following the evaluation, he was hospitalized with the diagnosis of pre-B cell Acute Lymphoblastic Leukemia (ALL) and was considered a chemotherapy regimen consisting of vincristine, methotrexate, cytarabine, and prednisolone. Prior to initiating the treatment, he was diagnosed with COVID-19 with manifestations of fever and dyspnea on the 20th day of hospitalization. The positive Polymerase Chain Reaction (PCR) test confirmed the diagnosis. On the 8th day of COVID-19 related clinical and paraclinical manifestations, the patient was complaining about a vague severe pain in the pelvic region predominantly around his hips. A pelvic MRI was performed to rule out critical etiologies and perimuscular and intramuscular edema was revealed. Creatine Phosphokinase (CPK) and Lactate Dehydrogenase (LDH) were elevated in the lab tests.&#x0D; His pain was diminished in few days spontaneously and diagnosis of myositis was confirmed.&#x0D; Myositis can be one of the extra-pulmonary manifestations of COVID-19. Therefore, finding out the association between myositis and COVID-19 can be beneficial for the early diagnosis and prevention of misleading.

AMG-232, a New Inhibitor of MDM-2, Enhance Doxorubicin Efficiency in Pre-B Acute Lymphoblastic Leukemia Cells.

Doxorubicin (DOX)-induced cardiotoxicity appears to be a growing concern for extensive use in acute lymphoblastic leukemia (ALL). The new combination treatment strategies, therefore might be an effective way of decreasing its side effects as well as improving efficacy. AMG232 (KRT-232) is a potential MDM-2 inhibitor, increasing available p53 through disturbing p53-MDM-2 interaction. In this study, we examined the effects of AMG232 on DOX-induced apoptosis of NALM-6 cells. The anti-leukemic effects of Doxorubicin on NALM-6 cells, either alone or in combination with AMG232, were confirmed by MTT assay, Annexin/PI apoptosis assay, and cell cycle analysis. Expression of apoptosis and autophagy-related genes were further evaluated by Real time-PCR method. To investigate the effect of AMG232 on NALM-6 cells, the activation of p53, p21, MDM-2, cleaved Caspase-3 proteins was evaluated using western blot analysis. The results showed that AMG232 inhibition of MDM-2 enhances Doxorubicin-induced apoptosis in NALM-6 cells through caspase-3 activation in a time and dose-dependent manner. Furthermore, co-treatment of AMG232 with Doxorubicin hampered the transition of NALM-6 cells from G1 phase through increasing p21 protein. In addition, this combination treatment led to enhanced expression of apoptosis and autophagy-related genes in ALL cell lines. The results declared that AMG232 as an MDM-2 inhibitor could be an effective approach to enhance antitumor effects of Doxorubicin on NALM-6 cells as well as an effective future treatment for ALL patients.

Identification of new ETV6 modulators through a high-throughput functional screening

SummaryETV6 transcriptional activity is critical for proper blood cell development in the bone marrow. Despite the accumulating body of evidence linking ETV6 malfunction to hematological malignancies, its regulatory network remains unclear. To uncover genes that modulate ETV6 repressive transcriptional activity, we performed a specifically designed, unbiased genome-wide shRNA screen in pre-B acute lymphoblastic leukemia cells. Following an extensive validation process, we identified 13 shRNAs inducing overexpression of ETV6 transcriptional target genes. We showed that the silencing of AKIRIN1, COMMD9, DYRK4, JUNB, and SRP72 led to an abrogation of ETV6 repressive activity. We identified critical modulators of the ETV6 function which could participate in cellular transformation through the ETV6 transcriptional network.

Targeting eIF4F translation complex sensitizes B-ALL cells to tyrosine kinase inhibition

The mechanistic target of rapamycin (mTOR) is a kinase whose activation is associated with poor prognosis in pre-B cell acute lymphoblastic leukemia (B-ALL). These and other findings have prompted diverse strategies for targeting mTOR signaling in B-ALL and other B-cell malignancies. In cellular models of Philadelphia Chromosome-positive (Ph+) B-ALL, mTOR kinase inhibitors (TOR-KIs) that inhibit both mTOR-complex-1 (mTORC1) and mTOR-complex-2 (mTORC2) enhance the cytotoxicity of tyrosine kinase inhibitors (TKIs) such as dasatinib. However, TOR-KIs have not shown substantial efficacy at tolerated doses in blood cancer clinical trials. Selective inhibition of mTORC1 or downstream effectors provides alternative strategies that may improve selectivity towards leukemia cells. Of particular interest is the eukaryotic initiation factor 4F (eIF4F) complex that mediates cap-dependent translation. Here we use novel chemical and genetic approaches to show that selective targeting of either mTORC1 kinase activity or components of the eIF4F complex sensitizes murine BCR-ABL-dependent pre-B leukemia cells to dasatinib. SBI-756, a small molecule inhibitor of eIF4F assembly, sensitizes human Ph+ and Ph-like B-ALL cells to dasatinib cytotoxicity without affecting survival of T lymphocytes or natural killer cells. These findings support the further evaluation of eIF4F-targeted molecules in combination therapies with TKIs in B-ALL and other blood cancers.