IL-7 Receptor Mutations and Steroid Resistance in Pediatric T cell Acute Lymphoblastic Leukemia: A Genome Sequencing Study

Autor: Ronald van Marion, Andrew P. Stubbs, R.C. Buijsman, Rob Pieters, Eric Vroegindeweij, Guido J.R. Zaman, Willem K. Smits, Kirsten Canté-Barrett, Peter J. van der Spek, Jessica G.C.A.M. Buijs-Gladdines, Roland P. Kuiper, Yunlei Li, Winand N.M. Dinjens, Martin A. Horstmann, Jules P.P. Meijerink
Přispěvatelé: Pediatrics, Pathology, Hematology
Jazyk: angličtina
Rok vydání: 2016
Předmět:
0301 basic medicine
Neuroblastoma RAS viral oncogene homolog
lcsh:Medicine
medicine.disease_cause
Bioinformatics
Pediatrics
Hematologic Cancers and Related Disorders
Signaling Molecules
Database and Informatics Methods
Cell Signaling
Medicine and Health Sciences
Exome
Genome Sequencing
Child
Exome sequencing
Mutation
Genome
Organic Compounds
General Medicine
Hematology
Genomics
Precursor Cell Lymphoblastic Leukemia-Lymphoma
Acute Lymphoblastic Leukemia
Genomic Databases
Gene Expression Regulation
Neoplastic
Chemistry
Oncology
Child
Preschool
Physical Sciences
Lymphoblastic Leukemia
Steroids
Signal transduction
Research Article
Signal Transduction
Cell signaling
Signal Inhibition
Adolescent
Antineoplastic Agents
Biology
Research and Analysis Methods
03 medical and health sciences
Diagnostic Medicine
Leukemias
medicine
Genetics
Humans
Interleukin-7 receptor
Molecular Biology Techniques
Sequencing Techniques
Protein kinase B
Molecular Biology
PI3K/AKT/mTOR pathway
Interleukin-7
Organic Chemistry
lcsh:R
Chemical Compounds
Cancers and Neoplasms
Biology and Life Sciences
Computational Biology
Cell Biology
Sequence Analysis
DNA
Genome Analysis
030104 developmental biology
Biological Databases
Drug Resistance
Neoplasm
Zdroj: PLoS Medicine, Vol 13, Iss 12, p e1002200 (2016)
PLoS Medicine
PLoS Medicine (online), 13(12):e1002200. Public Library of Science
ISSN: 1549-1676
1549-1277
Popis: Background Pediatric acute lymphoblastic leukemia (ALL) is the most common childhood cancer and the leading cause of cancer-related mortality in children. T cell ALL (T-ALL) represents about 15% of pediatric ALL cases and is considered a high-risk disease. T-ALL is often associated with resistance to treatment, including steroids, which are currently the cornerstone for treating ALL; moreover, initial steroid response strongly predicts survival and cure. However, the cellular mechanisms underlying steroid resistance in T-ALL patients are poorly understood. In this study, we combined various genomic datasets in order to identify candidate genetic mechanisms underlying steroid resistance in children undergoing T-ALL treatment. Methods and Findings We performed whole genome sequencing on paired pre-treatment (diagnostic) and post-treatment (remission) samples from 13 patients, and targeted exome sequencing of pre-treatment samples from 69 additional T-ALL patients. We then integrated mutation data with copy number data for 151 mutated genes, and this integrated dataset was tested for associations of mutations with clinical outcomes and in vitro drug response. Our analysis revealed that mutations in JAK1 and KRAS, two genes encoding components of the interleukin 7 receptor (IL7R) signaling pathway, were associated with steroid resistance and poor outcome. We then sequenced JAK1, KRAS, and other genes in this pathway, including IL7R, JAK3, NF1, NRAS, and AKT, in these 69 T-ALL patients and a further 77 T-ALL patients. We identified mutations in 32% (47/146) of patients, the majority of whom had a specific T-ALL subtype (early thymic progenitor ALL or TLX). Based on the outcomes of these patients and their prednisolone responsiveness measured in vitro, we then confirmed that these mutations were associated with both steroid resistance and poor outcome. To explore how these mutations in IL7R signaling pathway genes cause steroid resistance and subsequent poor outcome, we expressed wild-type and mutant IL7R signaling molecules in two steroid-sensitive T-ALL cell lines (SUPT1 and P12 Ichikawa cells) using inducible lentiviral expression constructs. We found that expressing mutant IL7R, JAK1, or NRAS, or wild-type NRAS or AKT, specifically induced steroid resistance without affecting sensitivity to vincristine or L-asparaginase. In contrast, wild-type IL7R, JAK1, and JAK3, as well as mutant JAK3 and mutant AKT, had no effect. We then performed a functional study to examine the mechanisms underlying steroid resistance and found that, rather than changing the steroid receptor’s ability to activate downstream targets, steroid resistance was associated with strong activation of MEK-ERK and AKT, downstream components of the IL7R signaling pathway, thereby inducing a robust antiapoptotic response by upregulating MCL1 and BCLXL expression. Both the MEK-ERK and AKT pathways also inactivate BIM, an essential molecule for steroid-induced cell death, and inhibit GSK3B, an important regulator of proapoptotic BIM. Importantly, treating our cell lines with IL7R signaling inhibitors restored steroid sensitivity. To address clinical relevance, we treated primary T-ALL cells obtained from 11 patients with steroids either alone or in combination with IL7R signaling inhibitors; we found that including a MEK, AKT, mTOR, or dual PI3K/mTOR inhibitor strongly increased steroid-induced cell death. Therefore, combining these inhibitors with steroid treatment may enhance steroid sensitivity in patients with ALL. The main limitation of our study was the modest cohort size, owing to the very low incidence of T-ALL. Conclusions Using an unbiased sequencing approach, we found that specific mutations in IL7R signaling molecules underlie steroid resistance in T-ALL. Future prospective clinical studies should test the ability of inhibitors of MEK, AKT, mTOR, or PI3K/mTOR to restore or enhance steroid sensitivity and improve clinical outcome.
Jules Meijerink and colleagues study mechanisms of steroid resistance in pediatric T-cell acute lymphoblastic leukemia.
Author Summary Why Was This Study Done? Although modern treatment protocols have drastically increased the cure rate among patients with T cell acute lymphoblastic leukemia (T-ALL), nearly 40% of patients require the most aggressive treatment regimen, significantly increasing the risk of harmful treatment effects later in life. These detrimental effects can include growth defects, bone necrosis, heart failure, and an increased risk of developing secondary malignancies. Moreover, treatment outcome for relapsed T-ALL patients is extremely poor. Steroids are the cornerstone chemotherapeutic drug in the treatment of acute lymphoblastic leukemia (ALL), including T-ALL. However, steroid resistance is common among patients and is associated with poor outcome and an increased risk of relapse. The mechanisms underlying steroid resistance in patients with ALL are poorly understood. Therefore, we performed an unbiased, comprehensive genetic analysis of pediatric T-ALL, as well as in vitro functional analyses to validate associations between the identified mutations and steroid resistance. What Did the Researchers Do and Find? We performed whole genome and targeted exome sequencing in patients with T-ALL and identified mutations in 151 genes, many of which are involved in cytokine signaling, transcriptional regulation, cell death, cell cycle, chromatin modification, and cellular transport. Mutation data were integrated with changes in chromosomal copy number and were correlated with the patients’ clinical features and underlying biological characteristics. Mutations in the IL7R signaling components JAK1 and KRAS were correlated with steroid resistance and poor outcome. Sequencing of IL7R signaling molecules in a larger pediatric T-ALL cohort revealed mutations in 32% of patients. Expressing specific mutant and/or wild-type IL7R signaling molecules in two steroid-sensitive T-ALL cell lines induced steroid resistance via robust downstream signaling through MEK-ERK and AKT, thereby reducing steroid-induced apoptosis. Moreover, treating these cells with inhibitors of IL7R signaling restored steroid sensitivity. Primary T-ALL cells obtained from patients were treated with steroids either alone or in combination with IL7R signaling inhibitors. We found that including these inhibitors significantly enhanced steroid-induced cell death. What Do These Findings Mean? These results should be tested further in prospective patient cohorts, to investigate the possibility that including IL7R signaling inhibitors in treatment regimens could restore or enhance steroid sensitivity in patients with ALL, thereby improving clinical outcomes.
Databáze: OpenAIRE
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