Project description:Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted treatment of childhood ALL, we performed a comprehensive transcriptome analysis yielding a set of genes specifically overexpressed in ALL. Among them we identified MondoA - a transcription factor regulating glycolysis in response to glucose availability. Here, we confirm that MondoA is highly overexpressed ALL, whereas the MondoA paralog, MondoB, is not expressed. Expression studies revealed that MondoA is not regulated by glucose availability in leukemia cells, but by the presence of lactate. An in silico MondoA promoter analysis identified two methylation-prone CpG-islands and four conserved binding sites for runt-related transcription factor 1 (RUNX1). In fact, MondoA and RUNX1 are significantly coexpressed in leukemia and experimental blockage of DNA methylation leads to a further induction of MondoA. In addition, using microarray profiling, gene-set enrichment analysis and RNA interference we provide for the first time evidence that MondoA expression not only increases glucose catabolism, but also maintains a more immature ALL phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data hint to an important contribution of MondoA to leukemia aggressiveness validating MondoA as an attractive candidate for targeted treatment of ALL. Two nonsense shRNA expressing control Nalm6 clones and three MondoA shRNA expressing Nalm6 clones were subjected to microarray analysis.
Project description:Acute lymphoblastic leukemia (ALL) is the most common childhood cancer. To identify novel candidates for targeted treatment of childhood ALL, we performed a comprehensive transcriptome analysis yielding a set of genes specifically overexpressed in ALL. Among them we identified MondoA - a transcription factor regulating glycolysis in response to glucose availability. Here, we confirm that MondoA is highly overexpressed ALL, whereas the MondoA paralog, MondoB, is not expressed. Expression studies revealed that MondoA is not regulated by glucose availability in leukemia cells, but by the presence of lactate. An in silico MondoA promoter analysis identified two methylation-prone CpG-islands and four conserved binding sites for runt-related transcription factor 1 (RUNX1). In fact, MondoA and RUNX1 are significantly coexpressed in leukemia and experimental blockage of DNA methylation leads to a further induction of MondoA. In addition, using microarray profiling, gene-set enrichment analysis and RNA interference we provide for the first time evidence that MondoA expression not only increases glucose catabolism, but also maintains a more immature ALL phenotype, which is associated with enhanced survival and clonogenicity of leukemia cells. These data hint to an important contribution of MondoA to leukemia aggressiveness validating MondoA as an attractive candidate for targeted treatment of ALL.
Project description:MondoA (also known as MLXIP), a member of the MYC interactome, has been described as an example of a metabolic sensor. By assessing patient data sets we found that MondoA overexpression is associated with a worse survival in pediatric common acute lymphoblastic leukemia (B-ALL). Using CRISPR/Cas9 and RNA interference approaches, we observed that MondoA depletion reduces transformational capacity of B-ALL cells in vitro and dramatically inhibits malignant potential in an in vivo mouse model. Interestingly, reduced expression of MondoA in patient data sets correlated with enrichment in metabolic pathways. The loss of MondoA correlated with increased tricarboxylic acid (TCA) cycle activity. Mechanistically, MondoA senses metabolic stress in B-ALL cells by restricting oxidative phosphorylation through reduced PDH activity. Glutamine starvation conditions greatly enhance this effect and highlight the inability to mitigate metabolic stress upon loss of MondoA in B-ALL. CHIPseq revealed a modest but highly significant redistribution of MYC towards binding sites shared with MondoA upon loss of MondoA.
Project description:MondoA (also known as MLXIP), a member of the MYC interactome, has been described as an example of a metabolic sensor. By assessing patient data sets we found that MondoA overexpression is associated with a worse survival in pediatric common acute lymphoblastic leukemia (B-ALL). Using CRISPR/Cas9 and RNA interference approaches, we observed that MondoA depletion reduces transformational capacity of B-ALL cells in vitro and dramatically inhibits malignant potential in an in vivo mouse model. Interestingly, reduced expression of MondoA in patient data sets correlated with enrichment in metabolic pathways. The loss of MondoA correlated with increased tricarboxylic acid (TCA) cycle activity. Mechanistically, MondoA senses metabolic stress in B-ALL cells by restricting oxidative phosphorylation through reduced PDH activity. Glutamine starvation conditions greatly enhance this effect and highlight the inability to mitigate metabolic stress upon loss of MondoA in B-ALL. CHIPseq revealed a modest but highly significant redistribution of MYC towards binding sites shared with MondoA upon loss of MondoA.
Project description:The Iroquois homeodomain transcription factor gene IRX3 is highly expressed in the developing nervous system, limb buds and heart. In adults, expression levels specify risk of obesity. We now report a significant functional role for IRX3 in human acute leukemia. While transcript levels are very low in normal human bone marrow cell populations, high level IRX3 expression is observed in ~30% of patients with acute myeloid leukemia (AML), ~50% of patients with T-acute lymphoblastic leukemia and ~20% of patients with B-acute lymphoblastic leukemia, typically in association with high levels of HOXA9. Expression of IRX3 alone was sufficient to immortalise murine bone marrow stem and progenitor cells, and induce T- and B-lineage leukemias in vivo with incomplete penetrance. IRX3 knockdown induced terminal differentiation of AML cells. Combined IRX3 and Hoxa9 expression in murine bone marrow stem and progenitor cells substantially enhanced the morphologic and phenotypic differentiation block of the resulting AMLs by comparison with Hoxa9-only leukemias, through suppression of a myelomonocytic program. Likewise, in cases of primary human AML, high IRX3 expression is associated with reduced myelomonocytic differentiation. Thus, tissue-inappropriate derepression of IRX3 modulates the cellular consequences of HOX gene expression to enhance differentiation block in human AML.
Project description:Transcription profiling of human T-cell lymphoblastic leukemia, acute mylelogenous leukemia and Diffuse Large Cell Lymphoma cell lines after treatment with aplidin and/or cytarabine
Project description:Transcription profiling of human acute lymphoblastic leukemia (ALL) in vitro models to investigate glucocorticoid-regulated microRNAs and mirtrons in ALL