Genetic studies in T-cell acute lymphoblastic leukemia have uncovered a remarkable complexity of oncogenic and loss-of-function mutations. Amongst this plethora of genetic changes, NOTCH1 activating mutations stand out as the most frequently occurring genetic defect, identified in more than 50% of T-cell acute lymphoblastic leukemias, supporting an essential driver role for this gene in T-cell acute lymphoblastic leukemia oncogenesis. In this study, we aimed to establish a comprehensive compendium of the long non-coding RNA transcriptome under control of Notch signaling. For this purpose, we measured the transcriptional response of all protein coding genes and long non-coding RNAs upon pharmacological Notch inhibition in the human T-cell acute lymphoblastic leukemia cell line CUTLL1 using RNA-sequencing. Similar Notch dependent profiles were established for normal human CD34+ thymic T-cell progenitors exposed to Notch signaling activity in vivo. In addition, we generated long non-coding RNA expression profiles (array data) from GSI treated T-ALL cell lines, ex vivo isolated Notch active CD34+ and Notch inactive CD4+CD8+ thymocytes and from a primary cohort of 15 T-cell acute lymphoblastic leukemia patients with known NOTCH1 mutation status. Integration of these expression datasets with publically available Notch1 ChIP-sequencing data resulted in the identification of long non-coding RNAs directly regulated by Notch activity in normal and malignant T-cell context. Given the central role of Notch in T-cell acute lymphoblastic leukemia oncogenesis, these data pave the way towards development of novel therapeutic strategies that target hyperactive Notch1 signaling in human T-cell acute lymphoblastic leukemia. Overall design: CUTLL1 cell lines were treated with Compound E (GSI) or DMSO (solvent control). Cells were collected 12 h and 48 h after treatment. This was performed for 3 replicates. RNA-sequencing was performed on these samples.
The Notch driven long non-coding RNA repertoire in T-cell acute lymphoblastic leukemia.
No sample metadata fields
View SamplesT-cell acute lymphoblastic leukemia (T-ALL) is mostly characterized by specific chromosomal abnormalities, some occurring in a mutually exclusive manner possibly delineating specific T-ALL subgroups. One subgroup, including MLL-rearranged, CALM-AF10 or inv(7)(p15q34) cases, is characterized by elevated expression of HOXA genes. Using a gene expression based clustering analysis of 67 T-ALL cases with recurrent molecular genetic abnormalities and 25 samples lacking apparent aberrations, we identified 5 new cases with elevated HOXA levels. Using array-CGH, a cryptic and recurrent deletion, del(9)(q34.11q34.13), was exclusively identified in 3 of these 5 cases. This deletion results in a conserved SET-NUP214 fusion product, that was also identified in the T-ALL cell line LOUCY. SET-NUP214 binds in the promoter regions of specific HOXA genes, where it may interact with CRM1 and DOT1L leading to the transcriptional activation of HOXA genes. Targeted inhibition of SET-NUP214 by siRNA abolished expression of HOXA genes, inhibited proliferation and induced differentiation in LOUCY but not in other T-ALL lines. We conclude that SET-NUP214 may contribute to the pathogenesis of T-ALL by enforcing T-cell differentiation arrest.
The recurrent SET-NUP214 fusion as a new HOXA activation mechanism in pediatric T-cell acute lymphoblastic leukemia.
No sample metadata fields
View SamplesT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive type of blood cancer resulting from malignant transformation of T-cell precursors. Several oncogenes, including the 'T-cell leukemia homeobox 1' TLX1 (HOX11) transcription factor, have been identified as early driver events that cooperate with other genetic aberrations in leukemic transformation of progenitor T-cells. The TLX1 controlled transcriptome in T-ALL has been investigated extensively in the past in terms of protein-coding genes, but remains unexplored thus far at the level of long non-coding RNAs (lncRNAs), the latter renown as well-established versatile and key players implicated in various cancer hallmarks. In this study, we present the first extensive analysis of the TLX1 regulated transcriptome focusing on lncRNA expression patterns. We present an integrative analysis of polyA and total RNA sequencing of ALL-SIL lymphoblasts with perturbed TLX1 expression and a primary T-ALL patient cohort (including 5 TLX1+ and 12 TLX3+ cases). We expanded our initially presented dataset of TLX1 and H3K27ac ChIP data in ALL-SIL cells (Durinck et al., Leukemia, 2015) with H3K4me1, H3K4me3, and ATAC-seq data to accurately define (super-) enhancer marked lncRNAs and assigned potential functional annotations to candidate TLX1-controlled lncRNAs through an in silico guilt-by-association approach. Our study paves the way for further functional analysis of selected lncRNAs as potential novel therapeutic targets for a precision medicine approach in the context of T-ALL. Overall design: polyA+ RNA-seq data was generated for a primary T-ALL patient cohort
A comprehensive inventory of TLX1 controlled long non-coding RNAs in T-cell acute lymphoblastic leukemia through polyA+ and total RNA sequencing.
Subject
View SamplesT-cell acute lymphoblastic leukemia (T-ALL) is an aggressive type of blood cancer resulting from malignant transformation of T-cell precursors. Several oncogenes, including the 'T-cell leukemia homeobox 1' TLX1 (HOX11) transcription factor, have been identified as early driver events that cooperate with other genetic aberrations in leukemic transformation of progenitor T-cells. The TLX1 controlled transcriptome in T-ALL has been investigated extensively in the past in terms of protein-coding genes, but remains unexplored thus far at the level of long non-coding RNAs (lncRNAs), the latter renown as well-established versatile and key players implicated in various cancer hallmarks. In this study, we present the first extensive analysis of the TLX1 regulated transcriptome focusing on lncRNA expression patterns. We present an integrative analysis of polyA and total RNA sequencing of ALL-SIL lymphoblasts with perturbed TLX1 expression and a primary T-ALL patient cohort (including 5 TLX1+ and 12 TLX3+ cases). We expanded our initially presented dataset of TLX1 and H3K27ac ChIP data in ALL-SIL cells (Durinck et al., Leukemia, 2015) with H3K4me1, H3K4me3, and ATAC-seq data to accurately define (super-) enhancer marked lncRNAs and assigned potential functional annotations to candidate TLX1-controlled lncRNAs through an in silico guilt-by-association approach. Our study paves the way for further functional analysis of selected lncRNAs as potential novel therapeutic targets for a precision medicine approach in the context of T-ALL. Overall design: Total RNA-seq data was generated for the T-ALL cell line ALL-SIL upon TLX1 knockdown
A comprehensive inventory of TLX1 controlled long non-coding RNAs in T-cell acute lymphoblastic leukemia through polyA+ and total RNA sequencing.
Cell line, Subject
View SamplesJuvenile myelomonocytic leukemia (JMML) is a very rare and aggressive stem cell disease that mainly occurs in young children. RAS activation constitutes the core component of oncogenic signaling. In addition, the leukemic blasts of a quarter of JMML patients present with monosomy 7 (-7), whereas more than half of the patients show enhanced age-adjusted fetal hemoglobin (HbF) levels. Hematopoietic stem cell transplantation is the current standard of care. This results in an event-free survival of 50 - 60%, indicating that novel molecular driven therapeutic options are urgently needed. Using gene expression profiling in an extensive series of 82 patient samples, we aimed at understanding the molecular biology behind JMML and identified a previously unrecognized molecular subgroup characterized by high LIN28B expression.
LIN28B overexpression defines a novel fetal-like subgroup of juvenile myelomonocytic leukemia.
Disease
View SamplesPurpose: The purpose of this study is to identify functionally inter-connected group of miRNAs whose reduced expression promotes leukemia development in vivo. We searched for relevant target genes of these miRNAs that are upregulated in T-ALL relative to controls. Methods: In order to examine the global gene expression, we generated 9 T-ALL patients and 4 normal controls by deep sequencing using Illumina Hi-Seq sequencer. The sequence reads that passed quality filters were analyzed using Spliced Transcripts Alignment to a Reference aligner (STAR) followed by differential gene expression analysis using DESeq. Results: Using an optimized data analysis workflow, we mapped reads per sample to the human genome (build hg19) and identified transcripts in both patient and controls with STAR workflow. We applied a machine learning approach to eliminate targets with redundant miRNA-mediated control. This strategy finds a convergence on the Myb oncogene and less prominent effects on the Hpb1 transcription factor. The abundance of both genes is increased in T-ALL and each can promote T-ALL in vivo. Conclusion: Our study reveals a Myc regulated network of tumor suppressor miRNAs in T-ALL. We identified a small number of functionally validated tumor suppressor miRNAs. These miRNAs are repressed upon Myc activation and this links their expression directly to Myb a key oncogenic driver in T-ALL. Overall design: Examination of global gene expression in 9 T-ALL patients and 4 normal controls using total RNA sequencing. BaseMeanA in DESeq_results.xlsx is the control.
Characterization of a set of tumor suppressor microRNAs in T cell acute lymphoblastic leukemia.
No sample metadata fields
View SamplesGenetic studies have shown that human T-ALLs can be divided into subgroups that are characterized by unique gene expression signatures and relate to stages of T-cell differentiation at which the leukemic cells arrest. Each molecular subgroup has characteristic genetic abnormalities that cause aberrant activation of specific T-ALL transcription factor oncogenes, including LYL1/MEF2C, HOXA, TLX1, TLX3 and TAL1/LMO2. Notably, the recently described Early T-cell Precursor ALL (ETP-ALL) patients have leukemic cells that show an early block in T-cell differentiation and significantly overlap with LYL1-positive T-ALL and MEF2C-dysregulated immature T-ALL. We studied the gene expression profiles of 64 primary T-ALL samples and found a high BCL-2 expression in immature T-ALL patients compared to patients belonging to other subgroups.
ABT-199 mediated inhibition of BCL-2 as a novel therapeutic strategy in T-cell acute lymphoblastic leukemia.
Specimen part
View SamplesEarly immature T-cell acute lymphoblastic leukemias (T-ALLs) account for about 5-10% of pediatric T-ALLs and are associated with poor prognosis. However, the genetic defects that drive the biology of these tumors remain largely unknown. Analysis of microarray gene expression signatures in adult T-ALL demonstrated a high prevalence of early immature leukemias and revealed a close relationship between these tumors and myeloid leukemias. Consistently, adult immature T- ALLs showed characteristic mutations in myeloid specific oncogenes and tumor suppressors including IDH1, IDH2, DNMT3A, FLT3 and NRAS. Moreover, we identified ETV6 mutations as a novel genetic lesion uniquely present in immature adult T-ALL. All together, our results demonstrate that early immature adult T- ALL represents a heterogeneous category of leukemias characterized by the presence of overlapping myeloid and T-ALL characteristics and highlight the role of ETV6 mutations in these tumors.
ETV6 mutations in early immature human T cell leukemias.
Specimen part
View SamplesTransgenic expression of TLX1 induces T-cell leukemias in mice.
The TLX1 oncogene drives aneuploidy in T cell transformation.
No sample metadata fields
View SamplesTo identify novel oncogenic pathways in T-cell acute lymphoblastic leukemia (T-ALL), we combined expression profiling of 117 pediatric patient samples and detailed molecular cytogenetic analyses including the Chromosome Conformation Capture on Chip (4C) method. Two T-ALL subtypes were identified that lacked rearrangements of known oncogenes. One subtype associated with cortical arrest, expression of cell cycle genes and ectopic NKX2-1 or NKX2-2 expression for which rearrangements were identified. The second subtype associated with immature T-cell development and high expression of the MEF2C transcription factor as consequence of rearrangements of MEF2C, transcription factors that target MEF2C or MEF2C-associated cofactors. We propose NKX2-1, NKX2-2 and MEF2C as T-ALL oncogenes that are activated by various rearrangements.
Integrated transcript and genome analyses reveal NKX2-1 and MEF2C as potential oncogenes in T cell acute lymphoblastic leukemia.
Specimen part
View Samples