RNA sequencing of 13 T-cell acute lymphoblastic leukemia patients (5 TCRAD-MYC translocated T-ALL_8TAL1-LMO2 T-ALL)
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ABSTRACT:
PROVIDER: PRJNA417699 | ENA |
REPOSITORIES: ENA
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Project description:RNA sequencing analysis revealed a different expression profile between two different T-ALL subgroups, namely MYC-TCRAD translocated T-ALL vs TAL1-LMO2 T-ALL.
2018-07-01 | GSE106699 | GEO
Project description:LMO2 is an oncogenic transcription factor that is frequently overexpressed due to chromosomal abnormalities in T-cell acute lymphoblastic leukemia (T-ALL). In transgenic mouse models, Lmo2 overexpression causes thymocyte self-renewal resulting in T-cell leukemia with long latency. However, the requirement for Lmo2 for leukemia maintenance is poorly understood. To study this, we developed a Tetracycline-regulated knock-in mouse model that reversibly expresses Lmo2 throughout the haematopoietic system. This led to a specific impairment of T-cell development and the development of self-renewing preleukemic stem cells (pre-LSCs) in the thymus, followed by the development of fully penetrant T-lymphoblastic leukemia resembling human T-ALL. In preleukemic mice, repression of Lmo2 overcame the LMO2-induced thymocyte developmental block, reversed Lmo2-induced gene expression changes and eliminated self-renewing pre-LSCs in vivo. In contrast, overt T-lymphoblastic leukemias arising in this model were either immature, Lmo2-dependent leukemias resembling human ETP-ALL, or mature leukemias which were Lmo2-independent. Genomic analyses identified frequent loss of tumour suppressor genes in Lmo2-independent T-ALLs. Deletion of one of these, Ikaros (Ikzf1), was sufficient to transform Lmo2-dependent tumours to Lmo2-independence. Together these results indicate an evolution of oncogene addiction in T-ALL and that loss of Ikaros can promote self-renewal of T-ALL lymphoblasts in the absence of initiating oncogenes.
2020-12-31 | GSE144035 | GEO
Project description:Prolonged or enhanced expression of the proto-oncogene Lmo2 is associated with a severe form of T-cell Acute Lymphoblastic Leukemia (T-ALL), designated Early T-progenitor ALL (ETP-ALL), that is characterized by the aberrant self-renewal and subsequent oncogenic transformation of immature thymocytes. Recent data suggest that Lmo2 may exert these effects by functioning as component of a multi-subunit transcription complex that includes the ubiquitous adapter Ldb1 along with b-HLH and/or GATA family transcription factors. In this study, we investigated the importance of Ldb1 for Lmo2-induced T-ALL by conditional deletion of Ldb1 in thymocytes in a Lmo2 transgenic mouse model of T-ALL. Our results identify a critical requirement for Ldb1 in the induction of thymocyte self-renewal, thymocyte radio-resistance and transition to T-ALL in Lmo2 transgenic mice. Ldb1 was also required for acquisition of the pre-leukemic ETP gene expression signature in immature Lmo2 transgenic thymocytes. Together, these results support a model where Lmo2-induced T-ALL results from failure to down-regulate Ldb/Lmo2 nucleated transcription complexes that normally function to enforce self-renewal in bone marrow hematopoietic progenitors
2020-03-19 | GSE129244 | GEO
Project description:Lmo2 is an oncogenic transcription factor that is a frequent target of chromosomal abnormalities in this T-cell acute lymphoblastic leukemia (T-ALL). In transgenic mouse models, overexpression of Lmo2 causes thymocyte self-renewal leading to T-cell leukemia with long latency. However, the requirement of Lmo2 for maintenance of overt leukemia is poorly understood. We found that Lyl1, a critical cofactor for Lmo2-induced leukemia, is frequently lost in cell lines derived from Lmo2-transgenic mice, raising the possibility that Lmo2 function is dispensable at this stage. To study this, we developed a Tetracycline-repressible knock-in mouse model (Vav-TRE-Lmo2), which expresses Lmo2 throughout the haematopoietic system. This led to specific effects on T-cell development and the development of T-cell leukemia with long latency, preceded by the presence of self-renewing T-cells in the thymus. Repression of Lmo2 overcame the Lmo2-induced thymocyte developmental block at the preleukemic stage and led to elimination of Lmo2-induced thymocyte self-renewal in vivo. In contrast, Lmo2 function was dispensable for the majority of overt Lmo2-induced T-cell leukemias as well as leukemia-derived cell lines, implying an evolution of oncogene addiction in the majority of T-cell leukemias. Lmo2-dependence in T-ALL was associated with an immature gene expression profile, but could not be predicted by immunophenotype or assessment of Notch pathway activation. Thus, Lmo2 can give rise to both Lmo2-depenent and –independent T-cell leukemias. The Vav-TRE-Lmo2 model should be useful to determine the molecular features associated with Lmo2-dependence, as well as the critical components of the Lmo2-induced self-renewal pathways in T-ALL.
2022-01-01 | GSE125674 | GEO
Project description:Aberrant co-expression of LMO2 and TAL1 is regularly found in T cell acute lymphoblastic leukemia (T-ALL). Here we describe a xenotransplant model for primary T-ALL cells derived from a patient who developed LMO2/TAL1 associated T-ALL after gene therapy for X-SCID (gamma c deficiency) due to insertional activation and a SIL-TAL1 fusion as an additional independent event. We identified a protein complex containing LMO2, TAL1 and E47 in the patient’s T-ALL cells. This complex functions as a transcription regulation complex in undifferentiated hematopoietic cells. However, its role in T-ALL is not fully understood. By comparative gene expression profiling we identified retinaldehyde dehydrogenase (RALDH2) as one of the genes which was highly up regulated in the primary T-ALL cells; the gene product was N-terminally truncated (RALDH2-T), but enzymatically active. To investigate the interference of LMO2 in RALDH2-T expression as well as the role of RALDH2-T in T-ALL development, LMO1 (analogue of LMO2) was down regulated by RNA interference in the T-ALL cell line Jurkat which led to a decrease of RALDH2-T expression and cell viability, indicating that positive regulation of RALDH2-T through an LMO1 or 2 containing transcription regulation complex might be essential for maintaining the T-ALL phenotype. Keywords: Primary human T-ALL cells and CD8 cells of normal donors
2008-12-27 | GSE6920 | GEO
Project description:T-cell acute lymphoblastic leukemia (T-ALL), an aggressive hematological tumor that arises from T-cell precursor cells, is often characterized by T cell receptor (TCR) translocations that drive aberrant activation of specific proto-oncogenes. Here, we performed a detailed molecular genetic characterization of a rare but aggressive genetic subtype of human T-ALL, ie. patients that present with a t(8;14)(q24;q11) translocation, in which high MYC levels are driven by enhancer elements of the TCR a/d locus (TCRAD-MYC). Notably, analysis of an extensive series of primary leukemia samples confirmed that TCRAD-MYC translocation positive T-ALLs represent a NOTCH1 independent subtype of T-cell leukemia characterized by aberrant activation of the TAL1 and/or LMO2 transcription factor oncogenes and frequent activation of the PI3K/AKT signaling pathway. From a therapeutic perspective, in vivo drug treatment experiments using primary patient derived xenografts revealed that TCRAD-MYC positive T-ALLs are sensitive to BET bromodomain inhibition, providing a rationale to develop BRD4 inhibitors as an adjuvant therapy for this rare, but genetically well-defined, high-risk subtype of human leukemia.
2018-07-01 | GSE106939 | GEO
Project description:Somatic mutations within non-coding genomic regions that aberrantly activate oncogenes have remained poorly characterized. Here we describe recurrent activating intronic mutations of LMO2, a prominent oncogene in T-cell acute lymphoblastic leukaemia (T-ALL). Heterozygous mutations were identified in PF-382 and DU.528 T-ALL cell lines, in addition to 3.7% (6/160) of paediatric and 5.5% (9/163) of adult T-ALL patient samples. The majority of indels harbor de novo MYB, ETS1 or RUNX1 consensus binding sites. Analysis of 5’-capped RNA transcripts in mutant cell lines identified the usage of an intermediate promoter site, with consequential monoallelic LMO2 overexpression. CRISPR/Cas9-mediated disruption of the mutant allele in PF-382 cells markedly downregulated LMO2 expression, establishing clear causality between the mutation and oncogene dysregulation. Furthermore, the spectrum of CRISPR/Cas9-derived mutations provide important insights into the interconnected contributions of functional transcription factor binding. Finally, these mutations occur in the same intron as retroviral integration sites in gene therapy induced T-ALL, suggesting that such events occur at preferential sites in the non-coding genome.
2017-03-15 | GSE94000 | GEO
Project description:To identify the binding partner of LMO2 for explanation of STAT3 signal-related protein in human glioblastoma
2022-08-11 | PXD028254 | Pride
Project description:Deregulated expression of oncogenic transcription factors is a common cause of T-cell acute lymphoblastic leukemia (T-ALL). However, the molecular and cellular effects of these transcription factors on developing T-cell progenitors are poorly understood. Here we show that the initial effect of the oncogenic transcription factor Lmo2 is to cause an almost complete block in differentiation at the DN2 stage of T-cell development.
2023-03-09 | GSE188225 | GEO
Project description:T-cell Acute Lymphoblastic Leukaemia (T-ALL) can be classified into a number of subfamilies, including those that overexpress TAL1/LMO, TLX1/3 and HOXA transcription factors. Whilst it has been previously shown in mouse models that TAL1/LMO transcription factors induce thymocyte self-renewal, whether this is the case for other transcription factor subclasses is currently unknown. To address this, we have studied vav-Nup98-HoxD13-transgenic (NHD13-Tg) mice, a model of HOXA-driven T-ALL, which overexpress HOXA transcription factors throughout haematopoiesis and display features of myelodysplastic syndrome in the bone marrow along with T-cell developmental abnormalities in the thymus and subsequent development of T-ALL in approximately 15% of mice. Thymocytes from preleukemic NHD13-Tg mice could engraft long-term in serial transplantation assays, demonstrating that NHD13-Tg thymocytes have acquired self-renewal capacity. Transcriptome analysis showed that NHD13-Tg thymocytes exhibited a Stem Cell like transcriptional program which closely resembled that of Lmo2 transgenic thymocytes, including Lmo2 itself and the critical Lmo2 cofactor Lyl1, suggesting a common mechanism of thymocyte self-renewal in these models. To determine whether Lmo2/Lyl1 are required for NHD13-induced thymocyte self-renewal, NHD13-Tg mice were crossed with Lyl1 knockout mice to generate NHD13-Tg mice lacking Lyl1. This showed that Lyl1 is essential for expression of the stem cell-like gene expression program in NHD13-Tg thymocytes and for thymocyte self-renewal. Surprisingly however, absence of Lyl1 accelerated the onset of T-ALL in NHD13-Tg mice. These studies demonstrate that Lyl1 is essential for self-renewal of NHD13-Tg thymocytes, suggesting that Lmo2 and Lyl1 may mediate thymocyte self-renewal induced by a variety of T-cell oncogenes. However, whilst Lyl1-induced thymocyte self-renewal is essential for Lmo2-driven T-cell leukemia, NHD13 can also promote T-ALL via an alternative pathway.
2019-03-04 | GSE121641 | GEO