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:The goal of the project was to discover proteines expressed in Extracellular Vesicles secreted by T-ALL or B-ALL (Acute Lymphoblastic Leukemia) cancer cells, when cells were amplified in vivo in Patient Derived Xenotransplanted (PDX) mice.
Project description:Proteogenomic analysis and genomic profiling, RNA-sequencing, and mass spectrometry-based analysis of High hyperdiploid childhood acute lymphoblastic leukemia.
Project description:Dysregulation of kinase signaling pathways via mutations favors tumor cell survival and resistance to therapy and it is common in cancer. Here, we reveal a novel mechanism of post-translational regulation of kinase signaling and nuclear receptor activity via deubiquitination in acute leukemia. We observed that the ubiquitin specific protease 11 (USP11) is highly expressed in lymphoblastic leukemia and associates with poor prognosis in this disease. USP11 ablation inhibits leukemia growth in vitro and in vivo, sparing normal hematopoiesis and thymus development, suggesting that USP11 could be a therapeutic target in leukemia. USP11 forms a complex with USP7 to deubiquitinate the oncogenic lymphocyte cell-specific protein-tyrosine kinase (LCK). Deubiquitination of LCK controls its activity, thereby altering T cell receptor signaling. Impairment of LCK activity leads to increased expression of the glucocorticoid receptor transcript, culminating into transcriptional activation of pro-apoptotic target genes, and sensitizes cells to glucocorticoids in primary T cell leukemia patient samples. The transcriptional activation of pro-apoptotic target genes, such as BCL2L11, is orchestrated by the deubiquitinase activity and mediated via an increase in enhancer-promoter interaction intensity. Pharmacological inhibition of USP7 or genetic knockout of USP7 in combination treatment of glucocorticoid displayed improved anti-T-ALL efficacy in vivo. Our data unveil how dysregulated deubiquitination controls signaling pathways, leading to cancer cell survival and drug non-response, and suggest novel therapeutic combinations towards targeting leukemia.