Polymorphisms of methylenetetrahydrofolate reductase (MTHFR) and susceptibility to pediatric acute lymphoblastic leukemia in a German study population

BACKGROUND: Methylenetetrahydrofolate reductase (MTHFR) has a major impact on the regulation of the folic acid pathway due to conversion of 5,10-methylenetetrahydrofolate (methylene-THF) to 5-methyl-THF. Two common polymorphisms (677C>T and 1298A>C) in the gene coding for MTHFR have been shown to reduce MTHFR enzyme activity and were associated with the susceptibility to different disorders, including vascular disease, neural tube defects and lymphoid malignancies. Studies on the role of these polymorphisms in the susceptibility to acute lymphoblastic leukemia (ALL) led to discrepant results. METHODS: We retrospectively evaluated the association of the MTHFR 677C>T and 1298A>C polymorphisms with pediatric ALL by genotyping a study sample of 443 ALL patients consecutively enrolled onto the German multicenter trial ALL-BFM 2000 and 379 healthy controls. We calculated odds ratios of MTHFR genotypes based on the MTHFR 677C>T and 1298A>C polymorphisms to examine if one or both of these polymorphisms are associated with pediatric ALL. RESULTS: No significant associations between specific MTHFR variants or combinations of variants and risk of ALL were observed neither in the total patient group nor in analyses stratified by gender, age at diagnosis, DNA index, immunophenotype, or TEL/AML1 rearrangement. CONCLUSION: Our findings suggest that the MTHFR 677C>T and 1298A>C gene variants do not have a major influence on the susceptibility to pediatric ALL in the German population

Methotrexate-associated toxicity in children with Down syndrome and acute lymphoblastic leukemia during consolidation therapy with high dose methotrexate according to ALL-BFM treatment regimen

Children with Down syndrome (DS) and acute lymphoblastic leukemia (ALL) often suffer from severe toxicities during treatment, especially with high-dose methotrexate (HD-MTX). Systematic data on methotrexate (MTX) toxicity in these patients are rare. We analyzed seven MTX-associated toxicities during consolidation therapy in 103 DS- and 1,109 non-DS-patients (NDS) with ALL (NDS-ALL) enrolled in ALL-Berlin-Frankfurt-Münster (ALL-BFM) trials between 1995-2016 and 1995-2007, respectively. Patients received four courses MTX (5 g/m2 each) plus intrathecal MTX and 6-mercaptopurine (6-MP). From 2004 onwards, a dose of 0.5 g/m2 in the first MTX course has been recommended for DS-patients. DS-patients showed higher rates of grade 3/4 toxicities after the first course with 5 g/m2 MTX compared to NDS-patients (grade 3/4 toxicities 62 in 45 DS-patients vs 516 in 1,089 NDS-patients, P<0.001). The dose reduction (0.5 g/m2) in DS-patients has reduced toxicity (39 in 51 patients, P<0.001) without increasing the relapse risk (reduced dose, 5-year cumulative relapse incidence = 0.09±0.04 vs high dose, 0.10±0.05, P=0.51). MTX dose escalation to 1.0 g/m2 for DS-patients who tolerated 0.5 g/m2 (n= 28 of 51 patients) did not result in an increased rate of grade 3/4 toxicities after the second course (P=0.285). Differences in MTX plasma levels at 42 and 48 hours after the start of the first methotrexate infusion did not explain higher toxicity rates in DS-patients treated with 0.5 g/m2 compared to NDS-patients treated with 5 g/m2 Within the DS cohort a higher MTX plasma level was associated with increased toxicity. In conclusion, dose reduction in the first MTX course reduced severe toxicities without increasing the risk of relapse. (ClinicalTrials.gov identifier: NTC00430118, NCT01117441)

Influence of cranial radiotherapy on outcome in children with acute lymphoblastic leukemia treated with contemporary therapy

Purpose We sought to determine whether cranial radiotherapy (CRT) is necessary to prevent relapse in any subgroup of children with acute lymphoblastic leukemia (ALL). Patients and Methods We obtained aggregate data on relapse and survival outcomes for 16,623 patients age 1 to 18 years old with newly diagnosed ALL treated between 1996 and 2007 by 10 cooperative study groups from around the world. The proportion of patients eligible for prophylactic CRT varied from 0%to 33% by trial and was not related to the proportion eligible for allogeneic stem-cell transplantation in first complete remission. Using a random effects model, with CRT as a dichotomous covariate, we performed a single-arm metaanalysis to compare event-free survival and cumulative incidence of isolated or any CNS relapse and isolated bone marrow relapse in high-risk subgroups of patients who either did or did not receive CRT. Results Although there was significant heterogeneity in all outcome end points according to trial, CRT was associated with a reduced risk of relapse only in the small subgroup of patients with overt CNS disease at diagnosis, who had a significantly lower risk of isolated CNS relapse (4% with CRT v 17% without CRT; P = .02) and a trend toward lower risk of any CNS relapse (7% with CRT v 17% without CRT; P = .09). However, this group had a relatively high rate of events regardless of whether or not they received CRT (32% [95% CI, 26% to 39%] v 34% [95% CI, 19% to 54%]; P = .8). Conclusion CRT does not have an impact on the risk of relapse in children with ALL treated on contemporary protocols

MAP3K7 is recurrently deleted in pediatric T-lymphoblastic leukemia and affects cell proliferation independently of NF-κB

Background: Deletions of 6q15–16.1 are recurrently found in pediatric T-cell acute lymphoblastic leukemia (T-ALL). This chromosomal region includes the mitogen-activated protein kinase kinase kinase 7 (MAP3K7) gene which has a crucial role in innate immune signaling and was observed to be functionally and prognostically relevant in different cancer entities. Therefore, we correlated the presence of MAP3K7 deletions with clinical parameters in a cohort of 327 pediatric T-ALL patients and investigated the function of MAP3K7 in the T-ALL cell lines CCRF-CEM, Jurkat and MOLT-4. Methods: MAP3K7 deletions were detected by multiplex ligation-dependent probe amplification (MLPA). T-ALL cell lines were transduced with adeno-associated virus (AAV) vectors expressing anti-MAP3K7 shRNA or a non-silencing shRNA together with a GFP reporter. Transduction efficiency was measured by flow cytometry and depletion efficiency by RT-PCR and Western blots. Induction of apoptosis was measured by flow cytometry after staining with PE-conjugated Annexin V. In order to assess the contribution of NF-κB signaling to the effects of MAP3K7 depletion, cells were treated with TNF-α and cell lysates analyzed for components of the NF-κB pathway by Western blotting and for expression of the NF-κB target genes BCL2, CMYC, FAS, PTEN and TNF-α by RT-PCR. Results: MAP3K7 is deleted in approximately 10% and point-mutated in approximately 1% of children with T-ALL. In 32 of 33 leukemias the deletion of MAP3K7 also included the adjacent CASP8AP2 gene. MAP3K7 deletions were associated with the occurrence of SIL-TAL1 fusions and a mature immunophenotype, but not with response to treatment and outcome. Depletion of MAP3K7 expression in T-ALL cell lines by shRNAs slowed down proliferation and induced apoptosis, but neither changed protein levels of components of NF-κB signaling nor NF-κB target gene expression after stimulation with TNF-α. Conclusions: This study revealed that the recurrent deletion of MAP3K7/CASP8AP2 is associated with SIL-TAL1 fusions and a mature immunophenotype, but not with response to treatment and risk of relapse. Homozygous deletions of MAP3K7 were not observed, and efficient depletion of MAP3K7 interfered with viability of T-ALL cells, indicating that a residual expression of MAP3K7 is indispensable for T-lymphoblasts

MAP3K7 is recurrently deleted in pediatric T-lymphoblastic leukemia and affects cell proliferation independently of NF-κB

Background: Deletions of 6q15–16.1 are recurrently found in pediatric T-cell acute lymphoblastic leukemia (T-ALL). This chromosomal region includes the mitogen-activated protein kinase kinase kinase 7 (MAP3K7) gene which has a crucial role in innate immune signaling and was observed to be functionally and prognostically relevant in different cancer entities. Therefore, we correlated the presence of MAP3K7 deletions with clinical parameters in a cohort of 327 pediatric T-ALL patients and investigated the function of MAP3K7 in the T-ALL cell lines CCRF-CEM, Jurkat and MOLT-4. Methods: MAP3K7 deletions were detected by multiplex ligation-dependent probe amplification (MLPA). T-ALL cell lines were transduced with adeno-associated virus (AAV) vectors expressing anti-MAP3K7 shRNA or a non-silencing shRNA together with a GFP reporter. Transduction efficiency was measured by flow cytometry and depletion efficiency by RT-PCR and Western blots. Induction of apoptosis was measured by flow cytometry after staining with PE-conjugated Annexin V. In order to assess the contribution of NF-κB signaling to the effects of MAP3K7 depletion, cells were treated with TNF-α and cell lysates analyzed for components of the NF-κB pathway by Western blotting and for expression of the NF-κB target genes BCL2, CMYC, FAS, PTEN and TNF-α by RT-PCR. Results: MAP3K7 is deleted in approximately 10% and point-mutated in approximately 1% of children with T-ALL. In 32 of 33 leukemias the deletion of MAP3K7 also included the adjacent CASP8AP2 gene. MAP3K7 deletions were associated with the occurrence of SIL-TAL1 fusions and a mature immunophenotype, but not with response to treatment and outcome. Depletion of MAP3K7 expression in T-ALL cell lines by shRNAs slowed down proliferation and induced apoptosis, but neither changed protein levels of components of NF-κB signaling nor NF-κB target gene expression after stimulation with TNF-α. Conclusions: This study revealed that the recurrent deletion of MAP3K7/CASP8AP2 is associated with SIL-TAL1 fusions and a mature immunophenotype, but not with response to treatment and risk of relapse. Homozygous deletions of MAP3K7 were not observed, and efficient depletion of MAP3K7 interfered with viability of T-ALL cells, indicating that a residual expression of MAP3K7 is indispensable for T-lymphoblasts

The SIOPE strategic plan: a European cancer plan for children and adolescents

Cancer in young people is rare, but it is still a major health issue in Europe. Each year, more than 6,000 young people in Europe die of cancer. There are more than 300,000 European childhood cancer survivors (in 2020, they will be nearly half a million): two-thirds of them have some late side effects of treatment, that are severe and impact on the daily life of half of those affected. Within the European Network for Cancer research in Children and Adolescents (ENCCA), SIOPE and the European paediatric haematology-oncology community have established a longterm sustainable Strategic Plan to increase the cure rate and the quality of survivorship for children and young people with cancer over the next ten years. The ultimate goal is to increase the disease- and late-effect- free survival after 10 years from the disease, and beyond. Seven medical and scientific objectives have been set up to achieve these goals: 1. Innovative treatments: to introduce safe and effective innovative treatments (i.e. new drugs, new technologies) into standard care; 2. Precision cancer medicine: to use improved risk classification as well as biological characteristics of both the tumour and patient (such as molecular and immunological factors) to help guide decisions on which therapies to use; 3. Tumour biology: to increase knowledge of tumour biology and speed up translation from basic research to clinical care to benefit patients; 4. Equal access: to bring about equal access across Europe to standard care (in both diagnosis and treatment), expertise and clinical research; 5. TYA: to address the specific needs of teenagers and young adults (TYA), in cooperation with adult oncology; 6. Quality of survivorship: to address the consequences of cancer treatment such as long-term side effects, to better understand the genetic background/risk of an individual, and to improve quality of life of childhood cancer survivors; 7. Causes of cancer: to understand the causes of paediatric cancers and to address prevention wherever possible

Repurposing anthelmintic agents to eradicate resistant leukemia

Despite rapid progress in genomic profiling in acute lymphoblastic leukemia (ALL), identification of actionable targets and prediction of response to drugs remains challenging. To identify specific vulnerabilities in ALL, we performed a drug screen using primary human ALL samples cultured in a model of the bone marrow microenvironment combined with high content image analysis. Among the 2487 FDA-approved compounds tested, anthelmintic agents of the class of macrocyclic lactones exhibited potent anti-leukemia activity, similar to the already known anti-leukemia agents currently used in induction chemotherapy. Ex vivo validation in 55 primary ALL samples of both precursor B cell and T-ALL including refractory relapse cases confirmed strong anti-leukemia activity with IC50 values in the low micromolar range. Anthelmintic agents increased intracellular chloride levels in primary leukemia cells, inducing mitochondrial outer membrane depolarization and cell death. Supporting the notion that simultaneously targeting cell death machineries at different angles may enhance the cell death response, combination of anthelmintic agents with the BCL-2 antagonist navitoclax or with the chemotherapeutic agent dexamethasone showed synergistic activity in primary ALL. These data reveal anti-leukemia activity of anthelmintic agents and support exploiting drug repurposing strategies to identify so far unrecognized anti-cancer agents with potential to eradicate even refractory leukemia

Hedgehog pathway mutations drive oncogenic transformation in high-risk T-cell acute lymphoblastic leukemia.

The role of Hedgehog signaling in normal and malignant T-cell development is controversial. Recently, Hedgehog pathway mutations have been described in T-ALL, but whether mutational activation of Hedgehog signaling drives T-cell transformation is unknown, hindering the rationale for therapeutic intervention. Here, we show that Hedgehog pathway mutations predict chemotherapy resistance in human T-ALL, and drive oncogenic transformation in a zebrafish model of the disease. We found Hedgehog pathway mutations in 16% of 109 childhood T-ALL cases, most commonly affecting its negative regulator PTCH1. Hedgehog mutations were associated with resistance to induction chemotherapy (P = 0.009). Transduction of wild-type PTCH1 into PTCH1-mutant T-ALL cells induced apoptosis (P = 0.005), a phenotype that was reversed by downstream Hedgehog pathway activation (P = 0.007). Transduction of most mutant PTCH1, SUFU, and GLI alleles into mammalian cells induced aberrant regulation of Hedgehog signaling, indicating that these mutations are pathogenic. Using a CRISPR/Cas9 system for lineage-restricted gene disruption in transgenic zebrafish, we found that ptch1 mutations accelerated the onset of notch1-induced T-ALL (P = 0.0001), and pharmacologic Hedgehog pathway inhibition had therapeutic activity. Thus, Hedgehog-activating mutations are driver oncogenic alterations in high-risk T-ALL, providing a molecular rationale for targeted therapy in this disease