Pediatric AbstractAcute Lymphoblastic Leukemia Research Articles

Abstract 4758: SETD4 transcription levels correlates with leukemic burden and SMYD2 transcription in acute lymphoblastic leukemia

Abstract Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy worldwide. It has a history of great rates of success in treatment, but adults and infants still share a dismal prognosis. This condition makes the development of new prognostic markers linked to effective therapeutic strategies a matter of pressing concern. While cancer has traditionally been viewed as a genetic disease derived from alterations in oncogenes and tumor suppressors, it is well known nowadays that epigenetic changes also play a fundamental role in tumorigenesis. The SET family of lysine methyltransferases (KMT) has been implicated in a number of cancers, and SETD4 is a member that is still poorly characterized. In the present study we used qPCR to analyze the expression pattern of SETD4 among 83 pediatric ALL patients and non-neoplastic bone marrow (BM) samples and investigated the correlation between SETD4 transcription changes with the leukemic burden in ALL patients during chemotherapy. We found that SETD4 transcription levels are significantly upregulated in BM samples derived from ALL patients compared to non-neoplastic BM (8,5-fold higher, p < 0,001) and its expression correlated with leukemic burden. Importantly, levels of SETD4 decreased in patients that responded to chemotherapy treatment. We further investigated whether SETD4 transcription levels associates with that of SMYD2, another KMT previously identified as a prognostic marker in ALL. Transcription levels of SETD4 and SMYD2 were examined on day 15th and 29th of chemotherapy. Surprisingly, a high level of correlation (Spearman r = 0.925, p < 0.01) between both genes was observed in both treatment time points. Finally, survival outcomes were worst in ALL patients with high levels of SETD4 transcription (log-rank test, p < 0,05), evidencing its dysregulated expression is associated with an unfavorable disease prognosis. Together, these results point to SETD4 as a useful prognostic marker, a possible tool to assess response to therapy and an attractive target for drug development. Citation Format: Luis Augusto Muniz Telles, Luis Henrique Sakamoto, Alan Jhones Assis, Doralina de Amaral Rabello, Andrea Barretto Motoyama, Fabio Pittella-Silva. SETD4 transcription levels correlates with leukemic burden and SMYD2 transcription in acute lymphoblastic leukemia. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 4758.

The triponderal mass index as a measure of adiposity in pediatric survivors of acute lymphoblastic leukemia: a cross-sectional study

Acute lymphoblastic leukemia (ALL) is the most common type of childhood cancer. Treatments of ALL predispose survivors to obesity, which increases the risk of cardiovascular disease and diabetes. The hallmark of obesity is excess fat mass, and adiposity is a superior predictor of cardiometabolic risk when compared to Body Mass Index (BMI), yet clinical measures of adiposity in children are lacking. The Tri-Ponderal Mass Index (TMI) (kg/m3) is a more accurate adiposity measure compared to BMI z-score in the general pediatric population. This cross-sectional study aimed to validate TMI as an adiposity measure against DEXA scan-derived adiposity, and to compare it to BMI z-score, in pediatric ALL survivors. This study was a retrospective chart review of pediatric ALL survivors diagnosed between 2004 and 2015 at McMaster Children’s Hospital, a tertiary pediatric center in Ontario, Canada. One hundred and thirteen patients (Female n = 55, 48.70%) were included, and adiposity was measured using DEXA scans. Exploratory partial correlations and linear regression analyses were adjusted for age, sex, ethnicity, and ALL risk status. Both TMI and BMI z-score correlated with the DEXA-measured fat mass percentage (FM%) (partial correlation TMI versus FM% r = 0.56; p value < 0.0001; BMI z-score versus FM% r = 0.55; p value < 0.0001). In regression analyses, the association of TMI was not inferior to BMI z-score in assessing adiposity (TMI versus FM% estimated unstandardized B 0.80, 95% CI 0.56, 1.02; p value < 0.0001; BMI z-score versus FM% (unstandardized B 0.37, 95% CI 0.26, 0.49; p value < 0.0001). The TMI is a useful clinical adiposity-specific measure in survivors of pediatric ALL.

Elevated expression of CDT1 in childhood acute lymphoblastic leukemia promotes cell proliferation, invasion and migration through activation of EMT.

Acute lymphoblastic leukemia (ALL) is a malignant disease of the hematopoietic system. At present, the mechanism and pathogenesis of ALL have not been fully clarified. This study aimed to illustrate the roles of Cdc10 protein-dependent transcript 1 (CDT1) in ALL. Real-Time Quantitative Polymerase Chain Reaction (RT-qPCR) was performed to examine serum levels of CDT1 in childhood ALL patients and healthy volunteers. The interaction between CDT1 expression and prognosis of childhood ALL was analyzed. Meanwhile, expressions of CDT1 in ALL cell lines were determined. Furthermore, CDT1 knockdown model was constructed in ALL cells, and Cell Counting Kit-8 (CCK-8), and Transwell assays were conducted to analyze the effect of CDT1 on the biological functions of ALL cells. Potential mechanism was further explored through detecting the expressions of Epithelial-to-mesenchymal transition (EMT)-related genes. RT-qPCR results indicated that serum level of CDT1 in childhood ALL patients was remarkably higher than that of healthy volunteers. Childhood ALL patients with high expression of CDT1 had lower overall survival rate compared with those expressing low expression of CDT1. CDT1 knockdown remarkably decreased the proliferation and metastasis abilities of pediatric ALL cells. Results of western blot showed that CDT1 might contribute to the malignant progression of childhood ALL via activating EMT. The findings showed that elevated CDT1 facilitated ALL metastasis by promoting EMT, suggesting that CDT1 played a pivotal role in ALL metastasis and may serve as a novel prognostic biomarker and therapeutic target.

The Earliest T-Precursors in the Mouse Embryo Are Susceptible to Leukemic Transformation.

Acute lymphoblastic leukemia (ALL) is the most common malignancy in pediatric patients. About 10–15% of pediatric ALL belong to T-cell ALL (T-ALL), which is characterized by aggressive expansion of immature T-lymphoblasts and is categorized as high-risk leukemia. Leukemia initiating cells represent a reservoir that is responsible for the initiation and propagation of leukemia. Its perinatal origin has been suggested in some childhood acute B-lymphoblastic and myeloblastic leukemias. Therefore, we hypothesized that child T-ALL initiating cells also exist during the perinatal period. In this study, T-ALL potential of the hematopoietic precursors was found in the para-aortic splanchnopleura (P-Sp) region, but not in the extraembryonic yolk sac (YS) of the mouse embryo at embryonic day 9.5. We overexpressed the Notch intracellular domain (NICD) in the P-Sp and YS cells and transplanted them into lethally irradiated mice. NICD-overexpressing P-Sp cells rapidly developed T-ALL while YS cells failed to display leukemia propagation despite successful NICD induction. These results suggest a possible role of fetal-derived T-cell precursors as leukemia-initiating cells.

Expression of YY1 in pro-B and T phenotypes correlation with poor survival in pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric cancer, constituting 80% of all acute leukemias in minors. Despite the increase in the success of therapies, disease-free survival is over 80% in most cases. For the remaining 20% of patients, new strategies are needed to allow us to know and select those at greatest risk of relapse. We evaluated by immunohistochemistry the expression of the transcription factor YY1 and found that it is overexpressed in peripheral blood leukemia cells of pediatric patients with ALL with Pro-B and T phenotype compared to control samples. Over expression of YY1 was associated with a significantly lower chance of survival. We also evaluated by RT-PCR in bone marrow samples from ALL pediatric patients the association of YY1 expression with the percentage of blasts. High levels of YY1 were present in samples with higher percent of blasts in these patients. In addition, ALL pediatric patients with a poor response to therapy had higher levels at the nuclear level of YY1 than those who responded well to chemotherapy. In conclusion, our data suggest that YY1 could serve in pediatric ALL as markers of evolution and response for this disease, mainly in patients with pro-B and T immunophenotype. It is also suggested that YY1 is implicated in the expanse of blast in these patients.

Long-term ovarian reserve and fertility outcomes in female survivors of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood malignancy, yet data regarding long-term ovarian reserve of female survivors are limited. The aim of this study was to investigate whether there is a differential pattern of anti-Mullerian hormone (AMH) levels in female childhood ALL survivors compared with the normal age-matched population. In a cohort of 56 female childhood ALL survivors (median age 29 years; median follow-up 20.6 years), a negative correlation was found between age at leukemia diagnosis and age-adjusted anti-Mullerian hormone (AMH) levels (r = −0.334, p = .031). Despite alkylating agent therapy, AMH levels did not differ significantly from age-related nomograms (age < 30, p = .17; age ≥ 30, p = .94). The mean number of children per fertile woman adjusted for maternal age was similar to the national average (2.76 versus 3.11, p = .19). Our results imply that reproductive outcomes are not significantly hampered in female pediatric ALL survivors. Long-term surveillance of ovarian reserve may enable personalized survivorship counseling.

The emerging role of NOTCH target genes in Egyptian childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL), characterized by overproduction and accumulation of immature lymphoid cells in bone marrow and peripheral blood, is the most common malignancy in children. NOTCH signaling is suggested to be a key event in hematological malignancies and appears to be a major oncogenic trigger in leukemia. Several studies on NOTCH target gene (HES‑1, p21 and c‑Myc) expression evaluated the correlation between these genes in AML (acute myeloid leukemia), but this relationship has not yet been clarified in ALL. Therefore, we aimed to study the expression of these genes in our Egyptian patients with ALL to obtain more information. RNA was extracted from peripheral blood mononuclear cells (PBMNCs) of 91 pediatric ALL patients (49 B-cell acute lymphoblastic leukemia [B-ALL] and 42 T-cell acute lymphoblastic leukemia [T-ALL]) and 52 healthy controls. The expression levels were determined by quantitative real-time polymerase chain reaction (qRT-PCR). Median p21 and HES1 expressions were down regulated, while c‑Myc expression was up-regulated in B‑ALL cases (p < 0.001, p = 0.008, p < 0.001, respectively) and in T‑ALL cases (p = 0.049, p = 0.015, p < 0.001, respectively) when compared to the control group. Median HES1 expression was down regulated, in B‑ALL cases compared to T‑ALL cases (p = 0.002), while P21 and c‑Myc did not differ significantly between B‑ALL and T‑ALL cases. P21 expression showed a significant positive correlation with HES1 expression and c‑Myc showed nonsignificant negative correlations with p21 and HES1, thus, suggesting that HES1 may affect ALL cells through the HES1–p21 pathway. Patients with over expressed c‑Myc had worse survival than patients with low expression which suggested it is a risk predictor.

Characterization of pharmacogenetic markers related to Acute Lymphoblastic Leukemia toxicity in Amazonian native Americans population

Acute Lymphoblastic Leukemia (ALL) is the most common cancer in children. Differences are found among ethnic groups in the results of the treatment of pediatric ALL. In general, children with a high level of native American ancestry tend to respond less positively to ALL treatments, which may be related to specific genomic variants found in native American groups. Despite the evidence, few data are available on the distribution of the pharmacogenomic variants relevant to the treatment of ALL in traditional Amerindian populations, such the those of the Amazon region. Given this, the present study investigated 27 molecular markers related to the treatment of ALL in Amerindians from Brazilian Amazonia and compared the frequencies with those recorded previously on five continents, that are available in the 1,000 Genomes database. The variation in the genotype frequencies among populations was evaluated using Fisher’s exact test. The False Discovery Rate method was used to correct the results of the multiple analyses. Significant differences were found in the frequencies of the majority of markers between the Amerindian populations and those of other regions around the world. These findings highlight the unique genetic profile of the indigenous population of Brazilian Amazonia, which may reflect a distinct therapeutic profile for the treatment of ALL in these populations.

Altered proteome of high-density lipoproteins from paediatric acute lymphoblastic leukemia survivors

Acute lymphoblastic leukemia (ALL) is the most frequent malignancy in children. With the use of more modern, efficient treatments, 5-year survival has reached more than 90% in this population. However, this achievement comes with many secondary and long-term effects since more than 65% of the survivors experience at least one severe complication, including the metabolic syndrome and cardiovascular diseases. The main objective of the present work was to characterize the composition of HDL particles isolated from pediatric ALL survivors. HDLs from 8 metabolically healthy ALL survivors, 8 metabolically unhealthy ALL survivors and 8 age- and gender-matched controls were analyzed. The HDL fraction from the survivors contained less cholesterol than the controls. In addition, proteomic analyses revealed an enrichment of pro-thrombotic (e.g., fibrinogen) and pro-inflammatory (e.g., amyloid A) proteins in the HDLs deriving from metabolically unhealthy survivors. These results indicate an alteration in the composition of lipid and protein content of HDL from childhood ALL survivors with metabolic disorders. Although more work is needed to validate the functionality of these HDLs, the data seem relevant for survivor health given the detection of potential biomarkers related to HDL metabolism and functionality in cancer.

Interactions Between Pseudomonas Immunotoxins and the Plasma Membrane: Implications for CAT-8015 Immunotoxin Therapy.

Acute Lymphoblastic Leukemia (ALL) remains the most frequent cause of cancer-related mortality in children and novel therapies are needed for the treatment of relapsed/refractory childhood ALL. One approach is the targeting of ALL blasts with the Pseudomonas immunotoxin CAT-8015. Although CAT-8015 has potent anti-leukemia activity, with a 32% objective response rate in a phase 1 study of childhood ALL, haemolytic-uremic syndrome (HUS) and vascular leak syndrome (VLS), major dose-limiting toxicities, have limited the use of this therapeutic approach in children. Investigations into the pathogenesis of CAT-8015-induced HUS/VLS are hindered by the lack of an adequate model system that replicates clinical manifestations, but damage to vascular endothelial cells (ECs) and blood cells are believed to be major initiating factors in both syndromes. Since there is little evidence that murine models replicate human HUS/VLS, and CAT-8015-induced HUS/VLS predominantly affects children, we developed human models and used novel methodologies to investigate CAT-8015 interactions with red blood cells (RBCs) from pediatric ALL patients and ECs of excised human mesenteric arteries. We provide evidence that CAT-8015 directly interacts with RBCs, mediated by Pseudomonas toxin. We also show correlation between the electrical properties of the RBC membrane and RBC susceptibility to CAT-8015-induced lysis, which may have clinical implication. Finally, we provide evidence that CAT-8015 is directly cytototoxic to ECs of excised human mesenteric arteries. In conclusion, the human models we developed constitutes the first, and very important, step in understanding the origins of HUS/VLS in immunotoxin therapy and will allow further investigations of HUS/VLS pathogenesis.

Molecular Pathways in Childhood Acute Lymphoblastic Leukemia: From the Bench to the Bedside

Acute lymphoblastic leukemia (ALL) is the most common cancer in childhood, originating from a neoplastic deviation of B or T lymphocyte. Cytogenetic, cytofluorimetric, and genomic analyses clearly defined several subtypes of ALL. However, the leukemogenic process is characterized by different pathways' alteration which are still to be determined, in the attempt to identify specific targets to be druggable. In this review, we explore the main molecular pathways, which are commonly shared between different subtypes of pediatric ALL. These cell-signaling pathways affect many functions, including cell proliferation, apoptosis, migration, and differentiation. The PI3K/AKT/mTOR pathway is one of the most studied, with higher expected promises of being targetable. RAS pathway is also widely studied in all types of cancer. The Wnt/Beta catenin has been recently studied in ALL. Finally, CXCL12/CXCL4 axis has a crucial role in regulating hematopoietic stem cell and bone marrow niche. The complete characterization of these pathways will allow us to design a specific patient–disease profile associated with a tailored treatment, with the highest grade of efficacy and the lowest grade of toxicity.

Polymorphism in IKZF1 gene affects age at onset of childhood acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer, characterized by a peak of incidence between 2 and 5 years. Since recently conducted genome-wide association (GWA) studies revealed that the common low-penetrance susceptibility allele at 7p12.2 (IKZF1 gene) confers an increased risk of pediatric ALL, we investigated whether the risk allele at rs4132601 also coexists with well-established prognostic factors, among 508 Polish pediatric patients with newly diagnosed ALL. Additionally, to verify whether the risk allele is favored by somatic tumor evolution, we examined the incidence of IKZF1 deletions in leukemic clones derived from 153 previously genotyped cases of pediatric ALL. Results of the analysis provide statistically significant support for an association between the rs4132601 polymorphic site and age at diagnosis of childhood ALL (p = 0.04). No association between allele variant and occurrence of IKZF1 deletions was found. These data provide further evidence of a biological role of gene variants in the development of ALL.

Acute Lymphoblastic Leukemia: Age and Biology

Acute lymphoblastic leukemia (ALL) is the most frequent neoplasm in children, while being relatively rare in adults. The outcome of children with ALL is far superior than that observed in adults, whose survival rates generally do not exceed 40%. A retrospective analysis recently carried out on a large series of cases enrolled in the AIEOP and GIMEMA protocols for the treatment of pediatric and adult ALL has documented specific differences among the various age cohorts examined, particularly in terms of incidence of molecular rearrangements, with the BCR/ABL rearrangement being detected in more than half of patients in the 6th decade of life. These findings highlight the importance of a precise diagnostic screening at all ages, since elderly patients might benefit more from targeted approaches, that are associated with less toxic effects. Furthermore, extended biologic approaches aimed at identifying novel therapeutic targets should be regarded as a main goal to refine our therapeutic armamentarium.Finally, the introduction of pediatric-like protocols is progressively changing the outcome of young adult patients, although an important caveat is represented by the comorbidities and toxic effects associated with more aggressive chemotherapy; therefore, patients' fitness should always be carefully considered.

Therapeutic Antibody Targeting of CD47 Eliminates Human Acute Lymphoblastic Leukemia

Acute lymphoblastic leukemia (ALL) is the most common pediatric malignancy and constitutes 15% of adult leukemias. Although overall prognosis for pediatric ALL is favorable, high-risk pediatric patients and most adult patients have significantly worse outcomes. Multiagent chemotherapy is standard of care for both pediatric and adult ALL, but is associated with systemic toxicity and long-term side effects and is relatively ineffective against certain ALL subtypes. Recent efforts have focused on the development of targeted therapies for ALL including monoclonal antibodies. Here, we report the identification of CD47, a protein that inhibits phagocytosis, as an antibody target in standard and high-risk ALL. CD47 was found to be more highly expressed on a subset of human ALL patient samples compared with normal cell counterparts and to be an independent predictor of survival and disease refractoriness in several ALL patient cohorts. In addition, a blocking monoclonal antibody against CD47 enabled phagocytosis of ALL cells by macrophages in vitro and inhibited tumor engraftment in vivo. Significantly, anti-CD47 antibody eliminated ALL in the peripheral blood, bone marrow, spleen, and liver of mice engrafted with primary human ALL. These data provide preclinical support for the development of an anti-CD47 antibody therapy for treatment of human ALL.

Tumor proliferative compartment, multidrug resistance gene product and apoptosis regulatory p53 and bcl-2 proteins in pediatric acute lymphoblastic leukemia

Acute lymphoblastic leukemia (ALL) is the most frequent childhood tumor. Although the cure rate has increased dramatically over the past few years, the molecular and cellular biology of this disease is still not fully understood. Important factors affecting prognosis include age, leucocyte count, cytogenetic abnormalities, immunophenotype and sex. However, the role of cell kinetics, tumor associated genes and drug resistance have rarely been investigated in pediatric ALL. This preliminary study looks at these aspects in this disease. Immunocytochemical analysis of the tumor suppressor protein p53, the anti apoptotic protein bcl-2, the multidrug resistance (MDR) gene product P-glycoprotein and the proliferation marker, Ki-67 were done using appropriate monoclonal antibodies. A total of 88 previously untreated children with confirmed ALL diagnosis and 40 age matched controls were included in the study. Ki-67 was expressed in 81% and P-glycoprotein in 68% of all cases. P53 expression was observed in 68% and Bcl-2 in 50% of cases. Fifty percent of all cases also showed concomitant expression of bcl-2 and p53. Since wild-type p53 is known to negatively regulate the expression of bcl-2, the co-expression of these two proteins having contrasting functions suggests that the p53 may be of a mutant variety. In addition, the expression of p53 also correlates to the presence of the multidrug gene product P-glycoprotein. Control samples were negative for all the four markers. P53, bcl-2 and P-glycoprotein can all influence chemotherapy resistance, the first two by regulating programmed cell death and the third by influencing intracellular drug levels. All patients are now being followed up to assess treatment response and to study the prognostic significance of the analyzed markers.