Comparative features and outcomes between paediatric T-cell and B-cell acute lymphoblastic leukaemia

A risk score system for stratifying the risk of relapse in B cell acute lymphocytic leukemia patients after allogenic stem cell transplantation

BACKGROUND

For patients with B cell acute lymphocytic leukemia (B-ALL) who underwent allogeneic stem cell transplantation (allo-SCT), many variables have been demonstrated to be associated with leukemia relapse. In this study, we attempted to establish a risk score system to predict transplant outcomes more precisely in patients with B-ALL after allo-SCT.

METHODS

A total of 477 patients with B-ALL who underwent allo-SCT at Peking University People's Hospital from December 2010 to December 2015 were enrolled in this retrospective study. We aimed to evaluate the factors associated with transplant outcomes after allo-SCT, and establish a risk score to identify patients with different probabilities of relapse. The univariate and multivariate analyses were performed with the Cox proportional hazards model with time-dependent variables.

RESULTS

All patients achieved neutrophil engraftment, and 95.4% of patients achieved platelet engraftment. The 5-year cumulative incidence of relapse (CIR), overall survival (OS), leukemia-free survival (LFS), and non-relapse mortality were 20.7%, 70.4%, 65.6%, and 13.9%, respectively. Multivariate analysis showed that patients with positive post-transplantation minimal residual disease (MRD), transplanted beyond the first complete remission (≥CR2), and without chronic graft-versus-host disease (cGVHD) had higher CIR (P  < 0.001, P = 0.004, and P  < 0.001, respectively) and worse LFS (P  < 0.001, P = 0.017, and P  < 0.001, respectively), and OS (P  < 0.001, P = 0.009, and P  < 0.001, respectively) than patients without MRD after transplantation, transplanted in CR1, and with cGVHD. A risk score for predicting relapse was formulated with the three above variables. The 5-year relapse rates were 6.3%, 16.6%, 55.9%, and 81.8% for patients with scores of 0, 1, 2, and 3 (P  < 0.001), respectively, while the 5-year LFS and OS values decreased with increasing risk score.

CONCLUSION

This new risk score system might stratify patients with different risks of relapse, which could guide treatment.

[Clinical features and prognosis of ETV6-RUNX1-positive childhood B-precursor acute lymphocyte leukemia]

目的

探讨ETV6-RUNX1融合基因阳性儿童急性前体B淋巴细胞白血病（B-ALL）的临床特征及预后。

方法

回顾性分析2011年4月至2020年5月福建医科大学附属协和医院小儿血液科收治的927例初诊B-ALL患儿的临床资料。根据ETV6-RUNX1检测结果，分为ETV6-RUNX1⁺组及ETV6-RUNX1⁻组，对比两组的临床特征及预后；182例ETV6-RUNX1⁺患儿规范治疗，其中144例接受中国儿童白血病协作组（CCLG）-ALL 2008方案治疗（CCLG-ALL 2008方案组），38例接受中国儿童癌症协作组（CCCG）-ALL 2015方案治疗（CCCG-ALL 2015方案组），对比两种方案的疗效、严重不良反应（SAE）发生率及治疗相关死亡（TRM）率。

结果

927例B-ALL患儿中，189例（20.4%）ETV6-RUNX1阳性。ETV6-RUNX1⁺组初诊时有危险因素（年龄≥10岁或<1岁，WBC≥50×10⁹/L）的患者比例均显著低于ETV6-RUNX1⁻组（P值分别为0.000和0.001），而泼尼松诱导试验反应良好、诱导化疗第15天或第19天微小残留病（MRD）<1%，以及诱导化疗第33天或第46天MRD<0.01%的患者比例显著高于ETV6-RUNX1⁻组（P值分别为0.001、0.028和0.004）。ETV6-RUNX1⁺组的5年无事件生存（EFS）及总生存（OS）率均显著高于ETV6-RUNX1⁻组（EFS：89.8%对83.2%，P＝0.003；OS：90.2%对86.3%，P＝0.030）。CCLG-ALL 2008组感染相关SAE发生率显著高于CCCG-ALL 2015组（27.1%对5.3%，P＝0.004），TRM发生率也高于CCCG-ALL 2015组，但差异无统计学意义（4.9%对0，P＝0.348）。

结论

ETV6-RUNX1⁺儿童B-ALL初诊危险因素较少，早期治疗反应较好，复发率低，总体预后良好；适当减低化疗强度，可降低感染相关SAE及TRM发生率，并进一步提高该亚型ALL患儿的OS率。

CDK9 Inhibitor Induces the Apoptosis of B-Cell Acute Lymphocytic Leukemia by Inhibiting c-Myc-Mediated Glycolytic Metabolism

B-cell acute lymphocytic leukemia (B-ALL), a common blood cancer in children, leads to high mortality. Cyclin-dependent kinase 9 inhibitor (CDK9i) effectively attenuates acute myeloid leukemia and chronic lymphoblastic leukemia by inducing apoptosis and inhibiting cell proliferation. However, the effect of CDK9i on B-ALL cells and the underlying mechanisms remain unclear. In this study, we showed that CDK9i induced the apoptosis of B-ALL cells in vitro by activating the apoptotic pathways. In addition, CDK9i restrained the glycolytic metabolism of B-ALL cells, and CDK9i-induced apoptosis was enhanced by co-treatment with glycolysis inhibitors. Furthermore, CDK9i restained the glycolysis of B-ALL cell lines by markedly downregulating the expression of glucose transporter type 1 (GLUT1) and the key rate-limiting enzymes of glycolysis, such as hexokinase 2 (HK2) and lactate dehydrogenase A (LDHA). Moreover, cell apoptosis was rescued in B-ALL cells with over-expressed c-Myc after treatment with CDK9i, which is involved in the enhancement of glycolytic metabolism. In summary, our findings suggest that CDK9 inhibitors induce the apoptosis of B-ALL cells by inhibiting c-Myc-mediated glycolytic metabolism, thus providing a new strategy for the treatment of B-ALL.

Decitabine inhibits the proliferation of human T-cell acute lymphoblastic leukemia molt4 cells and promotes apoptosis partly by regulating the PI3K/AKT/mTOR pathway

T cell acute lymphoblastic leukemia (T-ALL) is a highly aggressive hematological cancer; however, there is a lack of effective chemotherapeutic or targeted drugs for the treatment of T-ALL. Decitabine is a DNA demethylation agent but it has not been used for T-ALL treatment. Therefore, the present study aimed to assess the inhibitory effect of decitabine on T-ALL molt4 cells and determine its regulatory role in the PI3K/AKT/mTOR pathway. Molt4 cells were stimulated with decitabine in vitro, after which cell proliferation, apoptosis and cell cycle analyses were performed to assess cell viability. Subcellular morphology was observed using transmission electron microscopy. Expression levels of phosphate and tension homology (PTEN), genes involved in the PI3K/AKT/mTOR pathway and the corresponding downstream genes were analyzed using reverse transcription-quantitative PCR and western blotting. The results showed that decitabine induced apoptosis, inhibited proliferation and arrested molt4 cells in the G₂ phase. Following decitabine intervention, an increase in the number of lipid droplets, autophagosomes and mitochondrial damage was observed. At concentrations of 1 and 10 µM, decitabine downregulated the expression of PI3K, AKT, mTOR, P70S6 and eukaryotic initiating factor 4E-binding protein 1, which in turn upregulated PTEN expression; however, 50 µM decitabine downregulated PTEN levels. Overall, these results demonstrated that decitabine reduced the viability of molt4 cells partly by inhibiting the PI3K/AKT/mTOR pathway via PTEN, especially at low decitabine concentrations.

Dextromethorphan Administration on Day 0 and Day 7 for Secondary Prevention of Methotrexate-induced Neurotoxicity in Childhood Acute Lymphoblastic Leukemia: A Retrospective Case Series

Acute lymphoblastic leukemia is the most common malignancy in children. Long-term survival exceeds 90%; however, therapy-induced toxicity remains a concern. Methotrexate neurotoxicity (MTX-NT) is common, often necessitating alterations in chemotherapy regimens. Dextromethorphan has been used as an abortive and prophylactic treatment for MTX-NT. The authors report a case series of 7 pediatric patients with acute lymphoblastic leukemia with prior episodes of MTX-NT given a single dose of dextromethorphan (1 to 2 mg/kg) on the day of MTX administration and 7 days later. No subsequent episodes of MTX-NT occurred after 40 intravenous and 81 intrathecal administrations. This specific regimen of secondary prophylaxis may prevent MTX-NT.

BACH2-mediated FOS confers cytarabine resistance via stromal microenvironment alterations in pediatric ALL

Acute lymphoblastic leukemia (ALL) is an aggressive hematological cancer that mainly affects children. Relapse and chemoresistance result in treatment failure, underlining the need for improved therapies. BTB and CNC homology 2 (BACH2) is a lymphoid-specific transcription repressor recognized as a tumor suppressor in lymphomas, but little is known about its function and regulatory network in pediatric ALL (p-ALL). Herein, we found aberrant BACH2 expression at new diagnosis not only facilitated risk stratification of p-ALL but also served as a sensitive predictor of early treatment response and clinical outcome. Silencing BACH2 in ALL cells increased cell proliferation and accelerated cell cycle progression. BACH2 blockade also promoted cell adhesion to bone marrow stromal cells and conferred cytarabine (Ara-C)-resistant properties to leukemia cells by altering stromal microenvironment. Strikingly, we identified FOS, a transcriptional activator competing with BACH2, as a novel downstream target repressed by BACH2. Blocking FOS by chemical compounds enhanced the effect of Ara-C treatment in both primary p-ALL cells and pre-B-ALL-driven leukemia xenografts and prolonged the survival of tumor-bearing mice. These data highlight an interconnected network of BACH2-FOS, disruption of which could render current chemotherapies more effective and offer a promising therapeutic strategy to overcome Ara-C resistance in p-ALL.

Emerging molecular subtypes and therapeutic targets in B-cell precursor acute lymphoblastic leukemia

B-cell precursor acute lymphoblastic leukemia (BCP-ALL) is characterized by genetic alterations with high heterogeneity. Precise subtypes with distinct genomic and/or gene expression patterns have been recently revealed using high-throughput sequencing technology. Most of these profiles are associated with recurrent non-overlapping rearrangements or hotspot point mutations that are analogous to the established subtypes, such as DUX4 rearrangements, MEF2D rearrangements, ZNF384/ZNF362 rearrangements, NUTM1 rearrangements, BCL2/MYC and/or BCL6 rearrangements, ETV6-RUNX1-like gene expression, PAX5alt (diverse PAX5 alterations, including rearrangements, intragenic amplifications, or mutations), and hotspot mutations PAX5 (p.Pro80Arg) with biallelic PAX5 alterations, IKZF1 (p.Asn159Tyr), and ZEB2 (p.His1038Arg). These molecular subtypes could be classified by gene expression patterns with RNA-seq technology. Refined molecular classification greatly improved the treatment strategy. Multiagent therapy regimens, including target inhibitors (e.g., imatinib), immunomodulators, monoclonal antibodies, and chimeric antigen receptor T-cell (CAR-T) therapy, are transforming the clinical practice from chemotherapy drugs to personalized medicine in the field of risk-directed disease management. We provide an update on our knowledge of emerging molecular subtypes and therapeutic targets in BCP-ALL.

Prognostic Value and Outcome for ETV6/RUNX1-Positive Pediatric Acute Lymphoblastic Leukemia: A Report From the South China Children's Leukemia Group

PURPOSE

To analyzed the outcome of ETV6/RUNX1-positive pediatric acute B lymphoblastic leukemia (B-ALL) with the aim of identifying prognostic value.

METHOD

A total of 2,530 pediatric patients who were diagnosed with B-ALL were classified into two groups based on the ETV6/RUNX1 status by using a retrospective cohort study method from February 28, 2008, to June 30, 2020, at 22 participating ALL centers.

RESULTS

In total, 461 (18.2%) cases were ETV6/RUNX1-positive. The proportion of patients with risk factors (age <1 year or ≥10 years, WB≥50×10⁹/L) in ETV6/RUNX1-positive group was significantly lower than that in negative group (P<0.001), while the proportion of patients with good early response (good response to prednisone, D15 MRD < 0.1%, and D33 MRD < 0.01%) in ETV6/RUNX1-positive group was higher than that in the negative group (P<0.001, 0.788 and 0.004, respectively). Multivariate analysis of 2,530 patients found that age <1 or ≥10 years, SCCLG-ALL-2016 protocol, and MLL were independent predictor of outcome but not ETV6/RUNX1. The EFS and OS of the ETV6/RUNX1-positive group were significantly higher than those of the negative group (3-year EFS: 90.11 ± 4.21% vs 82 ± 2.36%, P<0.0001, 3-year OS: 91.99 ± 3.92% vs 88.79 ± 1.87%, P=0.017). Subgroup analysis showed that chemotherapy protocol, age, prednisone response, and D15 MRD were important factors affecting the prognosis of ETV6/RUNX1-positive children.

CONCLUSIONS

ETV6/RUNX1-positive pediatric ALL showed an excellent outcome but lack of independent prognostic significance in South China. However, for older patients who have the ETV6/RUNX1 fusion and slow response to therapy, to opt for more intensive treatment.

The genomic landscape of pediatric acute lymphoblastic leukemia and precision medicine opportunities

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer and constitutes approximately 25 % of cancer diagnoses among children under the age of 15 (Howlader et al., 2013) [1]. Overall, about half of ALL cases occur in children and adolescents and it is the most common acute leukemia until the early 20s, after which acute myeloid leukemia predominates. ALL is the most successful treatment paradigm in pediatric cancer medicine as illustrated by the significant survival rate improvement from ∼10 % in the 1960s to >90 % today (Hunger et al., 2015) [2]. This remarkable success stems from the progressive improvement in the efficacy of risk-adapted multiagent chemotherapy regimens with effective central nervous system (CNS) prophylaxis via well-designed randomized clinical trials conducted by international collaborative consortia, enhanced supportive care measures to decrease treatment-related mortality, in-depth understanding of the genetic basis of ALL, and refinement in treatment response assessment through serial minimal residual disease (MRD) monitoring (Pui et al., 2015) [3]. These advances collectively contribute to a decline in mortality rate of 23.5% for children diagnosed with ALL in the US from 2000 to 2010 (Smith et al., 2014) [4]. Nevertheless, outcomes of older adolescents and young adults with ALL still lag behind those of their younger counterparts despite pediatric-inspired chemotherapy regimens (Stock et al., 2019) [5], relapsed/refractory childhood ALL is associated with poor outcomes (Rheingold et al., 2019) [6], and ALL still represents the leading causes of cancer-related deaths (Smith et al., 2010) [7]. The last two decades have witnessed important genomic discoveries in ALL, enabled by advances in next-generation sequencing (NGS) technologies to characterize the landscape of germline and somatic alterations in ALL, some of which have important diagnostic, prognostic and therapeutic implications. Comprehensive genomic analysis of large cohorts of children and adults with ALL has revised the taxonomy of ALL in the molecular era by identifying novel clonal, subtype-defined chromosomal alterations associated with distinct gene expression signatures, thus reducing the proportion of patients previously labelled as "Others" from 25 % to approximately 5 % (Mullighan et al., 2019) [8]. Insights into the genomics of ALL further provide compelling biologic rationale to expand the scope of precision medicine therapies for childhood ALL. Herein, we summarize a decade of genomic discoveries to highlight three different facets of precision medicine in pediatric ALL: 1) inherited predispositions of ALL; 2) relevant molecularly targeted therapies in genomically-defined ALL subtypes; and 3) treatment response monitoring via pharmacogenomics and novel MRD biomarkers.

TPEN exerts selective anti-leukemic efficacy in ex vivo drug-resistant childhood acute leukemia

Despite some advances in the treatment of acute lymphoblastic (ALL) and myeloid leukemia (AML) in recent years, there is still a prominent percentage of pediatric patients with a reduced overall prognosis. Therefore, other therapeutic approaches are needed to treat those patients. In the present study, we report that the metal chelator TPEN affected ΔΨ_m and DNA content in isolated CD34⁺ refractory cells from bone marrow ALL (n = 7; B-cell, n = 4; T-cell, n = 3) and AML (n = 3) pediatric patients. Furthermore, TPEN induced oxidation of hydrogen peroxide (H₂O₂) sensor protein DJ-1, induced up-regulation of BH3-only pro-apoptotic protein PUMA, transcription factor p53 and activated the executor protease CASPASE-3 as apoptosis markers, and reduced the reactivity of the cellular proliferating marker Ki-67 in all acute leukemic groups, and reduced the phosphorylation of c-ABL protein signal in an AML case. Remarkably, bone marrow cells from non-leukemic patients' cells (n = 2) displayed neither loss of ΔΨ_m nor loss of DNA content when exposed to TPEN. We conclude that TPEN selectively induces apoptosis in acute leukemic cells via reactive oxygen species (ROS) signaling mechanism. Understanding the pathways of TPEN-induced cell death may provide insight into more effective therapeutic ROS-inducing anticancer agents.

Precision medicine in acute lymphoblastic leukemia

The cure rate of childhood acute lymphoblastic leukemia (ALL) has exceeded 90% in some contemporary clinical trials. However, the dose intensity of conventional chemotherapy has been pushed to its limit. Further improvement in outcome will need to rely more heavily on molecular therapeutic as well as immuno-and cellular-therapy approaches together with precise risk stratification. Children with ETV6-RUNX1 or hyperdiploid > 50 ALL who achieve negative minimal residual disease during early remission induction are suitable candidates for reduction in treatment. Patients with Philadelphia chromosome (Ph)-positive or Ph-like ALL with ABL-class fusion should be treated with dasatinib. BH3 profiling and other preclinical methods have identified several high-risk subtypes, such as hypodiplod, early T-cell precursor, immature T-cell, KMT2A-rearranged, Ph-positive and TCF-HLF-positive ALL, that may respond to BCL-2 inhibitor venetoclax. There are other fusions or mutations that may serve as putative targets, but effective targeted therapy has yet to be established. For other high-risk patients or poor early treatment responders who do not have targetable genetic lesions, current approaches that offer hope include blinatumomab, inotuzumab and CAR-T cell therapy for B-ALL, and daratumumab and nelarabine for T-ALL. With the expanding therapeutic armamentarium, we should start focus on rational combinations of targeted therapy with non-overlapping toxicities.

Alantolactone inhibits cell autophagy and promotes apoptosis via AP2M1 in acute lymphoblastic leukemia

Background

Acute lymphoblastic leukemia (ALL) is an aggressive hematopoietic malignancy that is most commonly observed in children. Alantolactone (ALT) has been reported to exhibit anti-tumor activity in different types of cancer. The aim of the present study was to investigate the anti-tumor activity and molecular mechanism of ALT in ALL.

Methods

ALL cell lines were treated with 1, 5 and 10 μM ALT, and cell viability was assessed using an MTT assay and RNA sequencing. Flow cytometry, JC-1 staining and immunofluorescence staining assays were used to measure cell apoptosis and autophagy. Additionally, western blot analysis was used to detect expression of apoptosis and autophagy related proteins. Finally, the effects of ALT on tumor growth were assessed in a BV173 xenograft nude mouse model.

Results

ALT inhibited the proliferation of ALL cells in a dose-dependent manner. Additionally, it was demonstrated that ALT inhibited cell proliferation, colony formation, autophagy, induced apoptosis and reduced tumor growth in vivo through upregulating the expression of adaptor related protein complex 2 subunit mu 1 (AP2M1). Moreover, the autophagy activator rapamycin, attenuated the pro-apoptotic effects of ALT on BV173 and NALM6 cell lines. Overexpression of AP2M1 decreased the expression of Beclin1 and the LC3-II/LC3-1 ratio, and increased p62 expression. Knockdown of Beclin1 increased the levels of bax, cleaved caspase 3 and cytochrome C, and decreased bcl-2 expression.

Conclusions

The present study demonstrated that ALT exerts anti-tumor activity through inducing apoptosis and inhibiting autophagy by upregulating AP2M1 in ALL, highlighting a potential therapeutic strategy for treatment of ALL.

Incidence, risk factors and outcome of extramedullary relapse after allogeneic hematopoietic stem cell transplantation in patients with adult acute lymphoblastic leukemia

Extramedullary relapse (EMR) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) continues to remain a clinical challenge. The data on EMR in acute lymphoblastic leukemia (ALL) are currently limited. Herein, a retrospective analysis of 268 adult ALL patients who underwent allo-HSCT in our center between March 2008 and December 2017 was performed to analyze post-HSCT EMR. Ninety patients (33.58%) experienced relapse; 51(19.03%) experienced bone marrow relapse (BMR), whereas 39 (14.55%) experienced EMR. The 5-year cumulative EMR incidence (CEMRI) revealed that matched sibling donor (MSD)-HSCTs were more likely to develop EMR than unrelated donor (URD)- and haploidentical-related donor (HRD)-HSCTs (CEMRI: 24.02%, 7.69%, and 14.69% for MSD, URD, and HRD, respectively). Notably, MSD-HSCTs (URD vs MSD hazard ratio (HR) = 0.26, p = 0.015; HRD vs MSD HR = 0.46, p = 0.032), history of extramedullary disease (EMD) (HR = 2.45, p = 0.041), and T cell ALL (HR = 2.80, p = 0.012) were independent risk factors for EMR in the multivariate analysis. The median overall survival (OS) for all patients was 15.23 months. However, the OS of EMR patients was significantly longer (19.50 months) than that of BMR patients (12.90 months) (p = 0.003). Multivariate analyses revealed that the leading risk factors for post-relapse deaths were shorter intervals between HSCT and relapse (> 12 months vs ≤ 12 months, HR = 0.30, p < 0.001) and BMR (HR = 0.41, p = 0.002). In conclusion, EMR patients have better survival than BMR patients. ALL patients with allo-HSCT from MSDs, a history of EMD, and the T cell type were significantly associated with EMR.

Clinical Characteristics and Treatment Results of Childhood Acute Lymphoblastic Leukemia in North Macedonia

BACKGROUND

Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. This study was designed to determine the clinical, biological features and outcomes among children with ALL treated at the only pediatric hematology-oncology center in North Macedonia.

PATIENTS AND METHODS

Seventy four consecutive children age 1 to 14 years, diagnosed with ALL between January 1, 2010 and October 31, 2017 and treated according to ALL IC BFM 2002 protocol were retrospectively evaluated.

RESULTS

The median age at diagnosis was 5 years and males were predominant (60.8%). Precursor B-cell ALL was diagnosed in 81.1% of patients, while 18.9% had T cell ALL. CNS involvement at the time of diagnoses was present in 6.8% of patients. Complete remission was achieved in 93.2% of patients. The induction death rate was 5.4%. The rate of death during first complete remission was 4.1%. Relapse occurred in 13.5% of patients. After a median observation time of 44 months, the 5-year overall survival (OS) and event-free survival (EFS) rates (± standard error) were 79.4% ± 5.2% and 74% ± 5.7%, respectively. The 5-year EFS rate for patients categorized as standard risk by NCI criteria was significantly higher than for high risk patients (83.3% versus 46.7%; P<0.001). Patients with precursor B-cell ALL and negative minimal residual disease (MRD) status at the end of induction had the best prognoses.

CONCLUSION

Our study demonstrated that the treatment results of childhood ALL in North Macedonia are comparable to those obtained in the ALL IC BFM 2002 trial.

Advantages and Limitations of SNP Array in the Molecular Characterization of Pediatric T-Cell Acute Lymphoblastic Leukemia

T-cell acute lymphoblastic leukemia (T-ALL) is a highly heterogeneous disease, and numerous genetic aberrations in the leukemic genome are responsible for the biological and clinical differences among particular ALL subtypes. However, there is limited knowledge regarding the association of whole-genome copy number abnormalities (CNAs) in childhood T-ALL with the course of leukemia and its outcome. The aim of this study was to identify the pattern of whole-genome CNAs in 86 newly diagnosed childhood T-ALL cases using a high-density single-nucleotide polymorphism array. We analyzed the presence of whole-genome CNAs with respect to immunophenotype, clinical features, and treatment outcomes. A total of 769 CNAs, including trisomies, duplications, deletions, and segmental loss of heterozygosity, were detected in 86 analyzed samples. Gain or loss of chromosomal regions exceeding 10 Mb occurred in 46 cases (53%), including six cases (7%) with complex chromosomal alterations. We observed that microdeletions in selected genes (e.g., FIP1L1 and PDGFRB) were related to the clinical features. Interestingly, 13% of samples have a duplication of the two loci (MYB and AIH1—6q23.3), which never occurred alone. Single-nucleotide polymorphism array significantly improved the molecular characterization of pediatric T-ALL. Further studies with larger cohorts of patients may contribute to the selection of prognostic CNAs in this group of patients.

Combination therapy of BCR-ABL-positive B cell acute lymphoblastic leukemia by tyrosine kinase inhibitor dasatinib and c-JUN N-terminal kinase inhibition

Background

The Philadelphia chromosome (Ph), which leads to the creation and expression of the fusion gene product BCR-ABL, underlines the pathogenesis of chronic myelogenous leukemia (CML) and a fraction of adult and pediatric acute B-lymphoblastic leukemia (B-ALL). The BCR-ABL tyrosine kinase inhibitors (TKIs) have shown a remarkable clinical activity in patients with CML, but their efficacy in treating Ph⁺ B-ALL is limited. Identifying additional therapeutic targets is important for the effective treatment of Ph⁺ B-ALL.

Methods

Activation of the JNK signaling pathway in human and mouse BCR-ABL⁺ B-ALL cells with or without dasatinib treatment was analyzed by Western blotting. JNK was inhibited either by RNA interference or chemical inhibitors, such as JNK-IN-8. The effect of JNK inhibition with or without BCR-ABL TKI dasatinib on BCR-ABL⁺ B-ALL cells was analyzed by the CellTiter-Glo® Luminescent Cell Viability Assay. The in vivo effects of JNK-IN-8 and dasatinib alone or in combination were tested using a BCR-ABL induced B-ALL mouse model.

Results

We found that the c-JUN N-terminal kinase (JNK) signaling pathway is abnormally activated in both human and mouse BCR-ABL⁺ B-ALL cells, but the BCR-ABL TKI does not inhibit JNK activation in these cells. Inhibition of JNK, either by RNAi-mediated downregulation or by JNK inhibitors, could significantly reduce viability of Ph⁺ B-ALL cells. JNK inhibition by RNAi-mediated downregulation or JNK inhibitors also showed a synergistic effect with the BCR-ABL TKI, dasatinib, in killing Ph⁺ B-ALL cells in vitro. Furthermore, a potent JNK inhibitor, JNK-IN-8, in combination with dasatinib markedly improved the survival of mice with BCR-ABL induced B-ALL, as compared to the treatment with dasatinib alone.

Conclusions

Our findings indicate that simultaneously targeting both BCR-ABL and JNK kinase might serve as a promising therapeutic strategy for Ph⁺ B-ALL.

Personalized therapy in pediatric high-risk B-cell acute lymphoblastic leukemia

Although cure rates for pediatric acute lymphoblastic leukemia (ALL) have now risen to more than 90%, subsets of patients with high-risk features continue to experience high rates of treatment failure and relapse. Recent work in minimal residual disease stratification and leukemia genomics have increased the ability to identify and classify these high-risk patients. In this review, we discuss this work to identify and classify patients with high-risk ALL. Novel therapeutics, which may have the potential to improve outcomes for these patients, are also discussed.

Cannabinoid CP55940 selectively induces apoptosis in Jurkat cells and in ex vivo T-cell acute lymphoblastic leukemia through H2O2 signaling mechanism

T-cell acute lymphoblastic leukemia (T-ALL) is a highly heterogeneous malignant hematological disorder arising from T-cell progenitors. This study was aimed to evaluate the cytotoxic effect of CP55940 on human peripheral blood lymphocytes (PBL) and on T-ALL cells (Jurkat). PBL and Jurkat cells were treated with CP55940 (0-20 μM), and morphological changes in the cell nucleus/ DNA, mitochondrial membrane potential (ΔΨm), and intracellular reactive oxygen species levels were determined by fluorescence microscopy and flow cytometry. Cellular apoptosis markers were also evaluated by western blotting, pharmacological inhibition and immunofluorescence. CP55940 induced apoptotic cell death in Jurkat cells, but not in PBL, in a dose-response manner with increasing fragmentation of DNA, arrest of cell cycle and damage of ΔΨm. CP55940 increased dichlorofluorescein fluorescence (DCF) intensity, increased DJ-1 Cys¹⁰⁶- sulfonate, a marker of intracellular stress, induced the up-regulation of p53 and phosphorylation of transcription factor c-JUN. It increased the expression of BAX and PUMA, up-regulated mitochondrial proteins PINK1 and Parkin, and activated CASPASE-3. Antioxidant NAC, pifithrin-α, and SP600125 blocked CP55940 deleterious effect on Jurkat cells. However, the potent and highly specific cannabinoid CB1 and CB2 receptor inverse agonist SR141716 and SR144528 were unable to blunt CP55940-induced apoptosis in Jurkat cells. Conclusively CP55940 provokes cell death in Jurkat through CBR-independent mechanism. Interestingly, CP55940 was also cytotoxic to ex vivo T-ALL cells from chemotherapy-resistant pediatric patients. In conclusion, CP55940 selectively induces apoptosis in Jurkat cells through a H₂O₂-mediated signaling pathway. Our findings support the use of cannabinoids as a potential treatment for T-ALL cells.

Harnessing immunotherapy for pediatric T-cell malignancies

Pediatric T-cell hematologic malignancies are a diverse group of rare cancers. The most common pediatric T-cell malignancies include T-cell acute lymphoblastic leukemia (T-ALL) and anaplastic large cell lymphoma (ALCL). Although the overall survival rates have improved markedly in recent years, children with relapsed T-ALL and ALCL have very low rates of cure and few salvage therapies exist. Current treatment regimens rely on toxic chemotherapies with significant short- and long-term morbidity. Immunotherapies, including antibodies and adoptive cellular therapies, have revolutionized the treatment of B-cell malignancies in pediatrics. The adaptation of these therapies to T-cell malignancies has been slower because of challenges implicit in the design and implementation of immunotherapies for T-cell malignancies, including the potential risks of fratricide, immunosuppression, and graft versus host disease (GVHD). We present a review of current challenges in the development of immunotherapies for T-cell hematologic malignancies, potential solutions and therapies under investigation. We include a particular focus on T-ALL and ALCL. Immunotherapies offer promising strategies to improve outcomes in children with T-cell malignancies, particularly in the setting of relapse. Optimizing efficacy, mitigating toxicity, and safely integrating with conventional therapies are key considerations as immunotherapies are translated into the clinic.

The Unfolded Protein Response: A Novel Therapeutic Target in Acute Leukemias

The unfolded protein response (UPR) is an evolutionarily conserved adaptive response triggered by the stress of the endoplasmic reticulum (ER) due, among other causes, to altered cell protein homeostasis (proteostasis). UPR is mediated by three main sensors, protein kinase RNA-like endoplasmic reticulum kinase (PERK), activating transcription factor 6α (ATF6α), and inositol-requiring enzyme-1α (IRE1α). Given that proteostasis is frequently disregulated in cancer, UPR is emerging as a critical signaling network in controlling the survival, selection, and adaptation of a variety of neoplasias, including breast cancer, prostate cancer, colorectal cancer, and glioblastoma. Indeed, cancer cells can escape from the apoptotic pathways elicited by ER stress by switching UPR into a prosurvival mechanism instead of cell death. Although most of the studies on UPR focused on solid tumors, this intricate network plays a critical role in hematological malignancies, and especially in multiple myeloma (MM), where treatment with proteasome inhibitors induce the accumulation of unfolded proteins that severely perturb proteostasis, thereby leading to ER stress, and, eventually, to apoptosis. However, UPR is emerging as a key player also in acute leukemias, where recent evidence points to the likelihood that targeting UPR-driven prosurvival pathways could represent a novel therapeutic strategy. In this review, we focus on the oncogene-specific regulation of individual UPR signaling arms, and we provide an updated outline of the genetic, biochemical, and preclinical therapeutic findings that support UPR as a relevant, novel target in acute leukemias.

How I treat newly diagnosed T-cell acute lymphoblastic leukemia and T-cell lymphoblastic lymphoma in children

T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive malignancy that has historically been associated with a very poor prognosis. Nevertheless, despite a lack of incorporation of novel agents, the development of intensified T-ALL-focused protocols has resulted in significant improvements in outcome in children. Through the use of several representative cases, we highlight the key changes that have driven these advances including asparaginase intensification, the use of induction dexamethasone, and the safe omission of cranial radiotherapy. We discuss the results of recent trials to explore key topics including the implementation of risk stratification with minimal residual disease measurement and how to treat high-risk subtypes such as early T-cell precursor ALL. In particular, we address current discrepancies in treatment between different cooperative groups, including the use of nelarabine, and provide rationales for current treatment protocols for both T-ALL and T-lymphoblastic lymphoma.

Measurable Residual Disease Assessed by Flow-Cytometry Is a Stable Prognostic Factor for Pediatric T-Cell Acute Lymphoblastic Leukemia in Consecutive SEHOP Protocols Whereas the Impact of Oncogenetics Depends on Treatment

Robust and applicable risk-stratifying genetic factors at diagnosis in pediatric T-cell acute lymphoblastic leukemia (T-ALL) are still lacking, and most protocols rely on measurable residual disease (MRD) assessment. In our study, we aimed to analyze the impact of NOTCH1, FBXW7, PTEN, and RAS mutations, the measurable residual disease (MRD) levels assessed by flow cytometry (FCM-MRD) and other reported risk factors in a Spanish cohort of pediatric T-ALL patients. We included 199 patients treated with SEHOP and PETHEMA consecutive protocols from 1998 to 2019. We observed a better outcome of patients included in the newest SEHOP-PETHEMA-2013 protocol compared to the previous SHOP-2005 cohort. FCM-MRD significantly predicted outcome in both protocols, but the impact at early and late time points differed between protocols. The impact of FCM-MRD at late time points was more evident in SEHOP-PETHEMA 2013, whereas in SHOP-2005 FCM-MRD was predictive of outcome at early time points. Genetics impact was different in SHOP-2005 and SEHOP-PETHEMA-2013 cohorts: NOTCH1 mutations impacted on overall survival only in the SEHOP-PETHEMA-2013 cohort, whereas homozygous deletions of CDKN2A/B had a significantly higher CIR in SHOP-2005 patients. We applied the clinical classification combining oncogenetics, WBC count and MRD levels at the end of induction as previously reported by the FRALLE group. Using this score, we identified different subgroups of patients with statistically different outcome in both Spanish cohorts. In SHOP-2005, the FRALLE classifier identified a subgroup of high-risk patients with poorer survival. In the newest protocol SEHOP-PETHEMA-2013, a very low-risk group of patients with excellent outcome and no relapses was detected, with borderline significance. Overall, FCM-MRD, WBC count and oncogenetics may refine the risk-stratification, helping to design tailored approaches for pediatric T-ALL patients.

Improved CNS Control of Childhood Acute Lymphoblastic Leukemia Without Cranial Irradiation: St Jude Total Therapy Study 16

PURPOSE

Despite contemporary treatment, up to 10% of children with acute lymphoblastic leukemia still experience relapse. We evaluated whether a higher dosage of PEG-asparaginase and early intensification of triple intrathecal therapy would improve systemic and CNS control.

PATIENTS AND METHODS

Between 2007 and 2017, 598 consecutive patients age 0 to 18 years received risk-directed chemotherapy without prophylactic cranial irradiation in the St Jude Total Therapy Study 16. Patients were randomly assigned to receive PEG-asparaginase 3,500 U/m2 versus the conventional 2,500 U/m2. Patients presenting features that were associated with increased risk of CNS relapse received two extra doses of intrathecal therapy during the first 2 weeks of remission induction.

RESULTS

The 5-year event-free survival and overall survival rates for the 598 patients were 88.2% (95% CI, 84.9% to 91.5%) and 94.1% (95% CI, 91.7% to 96.5%), respectively. Cumulative risk of any-isolated or combined-CNS relapse was 1.5% (95% CI, 0.5% to 2.5%). Higher doses of PEG-asparaginase did not affect treatment outcome. T-cell phenotype was the only independent risk factor for any CNS relapse (hazard ratio, 5.15; 95% CI, 1.3 to 20.6; P = . 021). Among 359 patients with features that were associated with increased risk for CNS relapse, the 5-year rate of any CNS relapse was significantly lower than that among 248 patients with the same features treated in the previous Total Therapy Study 15 (1.8% [95% CI, 0.4% to 3.3%] v 5.7% [95% CI, 2.8% to 8.6%]; P = .008). There were no significant differences in the cumulative risk of seizure or infection during induction between patients who did or did not receive the two extra doses of intrathecal treatment.

CONCLUSION

Higher doses of PEG-asparaginase failed to improve outcome, but additional intrathecal therapy during early induction seemed to contribute to improved CNS control without excessive toxicity for high-risk patients.

Childhood T-cell acute lymphoblastic leukemia in a single Latin American center: impact of improved treatment scheme and support therapy on survival

Background and objective

T-cell acute lymphoblastic leukemia (T-ALL) in children represents a high-risk disease. There is a lack of studies assessing the outcome of T-ALL in Hispanic populations, in which it is a rare malignancy. We report the characteristics and results of treatment for childhood T-cell ALL in children over 14 years at a Latin American reference center.

Material and methods

From January 2005 to December 2018, there occurred the analysis of twenty patients ≤ 16 years of age from a low-income open population diagnosed at a university hospital in Northeast Mexico. Clinical and laboratory characteristics, treatment regimens and outcomes were assessed by scrutinizing clinical records and electronic databases. Diagnosis was confirmed by flow cytometry, including positivity for CD-2, 5, 7 and surface/cytoplasmic CD3. Survival rates were assessed by the Kaplan-Meier method.

Results

There was a male preponderance (70 %), with a 2.3 male-to-female ratio (p =  .074), the median age being 9.5 years. Leucocytes at diagnosis were ≥ 50 × 10⁹/L in 13 (65 %) children, with CNS infiltration in 6 (30 %) and organomegaly in 10 (50 %). The five-year overall survival (OS) was 44.3 % (95 % CI 41.96–46.62), significantly lower in girls, at 20.8 % (95 % CI 17.32–24.51) vs. 53.1 % (95 % CI 50.30–55.82), (p = .035) in boys; there was no sex difference in the event-free survival (EFS) (p = .215). The survival was significantly higher after 2010 (p = .034).

Conclusion

The T-cell ALL was more frequent in boys, had a higher mortality in girls and the survival has increased over the last decade with improved chemotherapy and supportive care.

Immunotherapy in pediatric acute lymphoblastic leukemia

The 5-year survival rate for children and adolescents with acute lymphoblastic leukemia (ALL) has improved to more than 90% in high-income countries. However, further increases in the intensity of conventional chemotherapy would be associated with significant adverse effects; therefore, novel approaches are necessary. The last decade has seen significant advances in targeted therapy with immunotherapy and molecular therapeutics, as well as advances in risk stratification for therapy based on somatic and germline genetic analysis and monitoring of minimal residual disease. For immunotherapy, the approval of antibody-based therapy (with blinatumomab in 2014 and inotuzumab ozogamicin in 2017) and T cell-based therapy (with tisagenlecleucel in 2017) by the US Food and Drug Administration has significantly improved the response rate and outcomes in patients with relapsed/refractory B-ALL. These strategies have also been tested in the frontline setting, and immunotherapy against a new ALL-associated antigen has been developed. Incorporating effective immunotherapy into ALL therapy would enable the intensity of conventional chemotherapy to be decreased and thereby reduce associated toxicity, leading to further improvement in survival and quality of life for patients with ALL.