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Title: The genomic landscape of pediatric T-cell acute lymphoblastic leukemia reveals novel X-linked somatic mutations associated with apoptosis resistance. [RNA-Seq]      
dateReleased:
03-02-2016
description:
Background. T-cell acute lymphoblastic leukemia (T-ALL) is an aggressive hematological malignancy with a dismal prognosis. It represents 15% of pediatric ALL and has a threefold higher incidence among males. T-cell transformation is a multi-step process involving cooperating events leading to altered T-cell signaling, proliferation, differentiation and survival. Many recurrent alterations have been identified and help define molecular subgroups of T-ALL, however the full range of events involved in driving transformation remain to be defined. Results. Using an integrative approach combining genomic and transcriptomic data, we performed comprehensive molecular characterization of 30 pediatric T-ALLs. We identified common T-ALL targets and confirmed the overall poor outcome of early immature cases. We also showed that deletion of the CDKN2A locus is associated with lower risk of relapse. In addition, we identified novel T-ALL drivers including a member of the spliceosome machinery U2AF1 as well as novel X-linked tumor suppressors MED12 and USP9X, that had never been associated to T-ALL before. Interestingly, almost 60% of these events were found in early immature cases which represented only 35% of the cohort. Functional validations further demonstrated the putative role of these novel T-ALL genes in driving transformation by demonstrating the aberrant splicing provoked by U2AF1 p.R35L and the protective effect against apoptosis of MED12 and USP9X repression. Conclusions. This study highlights the underlying genomic complexity of pediatric T-ALL, and the need for larger integrative studies to decipher the mechanisms that contribute to its various subtypes and provide opportunities to refine patient stratification and treatment. Total RNA was extracted from bone marrow samples at diagnosis for patients 432, 437, 547, 693, 716, 743, 744, 748, 791 and 849 using the mirVana Isolation kit (Ambion) according to the manufacturer’s protocol. The Allprep DNA/RNA Mini kit (Qiagen) was used for relapse samples in patients 791 and 879. For patient 744, mature RNA was also purified using the Ambion's MicroPoly(A)Purist kit (Small Scale mRNA Purification Kit P/N AM1919). Following a DNAse I treatment, total or mature RNA samples were quantified by NanoDrop ND1000 (Thermo-Fisher Scientific) and RNA quality was assessed using the Agilent 2100 Bioanalyzer (Agilent). Ribosomal ribonucleic acid (rRNA) were depleted using the Invitrogen RiboMinus Eukaryote kit (Life Technologies). cDNA libraries were prepared using the SOLiD Total RNA-seq kit (diagnosis samples) and the Illumina TruSeq Stranded Total RNA kit (relapse samples) based on manufacturer’s protocol and sequenced on the Life Technologies SOLiD 5500 System or the Illumina HiSeq 2500 System.
privacy:
not applicable
aggregation:
instance of dataset
ID:
E-GEOD-78785
refinement:
raw
alternateIdentifiers:
78785
keywords:
functional genomics
dateModified:
03-05-2016
availability:
available
types:
gene expression
name:
Homo sapiens
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-78785/E-GEOD-78785.raw.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ebi.ac.uk/arrayexpress/files/E-GEOD-78785/E-GEOD-78785.processed.1.zip
storedIn:
ArrayExpress
qualifier:
gzip compressed
format:
TXT
accessType:
download
authentication:
none
authorization:
none
accessURL: https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE78785
storedIn:
Gene Expression Omnibus
qualifier:
not compressed
format:
HTML
accessType:
landing page
primary:
true
authentication:
none
authorization:
none
abbreviation:
EBI
homePage: http://www.ebi.ac.uk/
ID:
SCR:004727
name:
European Bioinformatics Institute
homePage: https://www.ebi.ac.uk/arrayexpress/
ID:
SCR:002964
name:
ArrayExpress

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