Project description:ERG-related B cell precursor acute lymphoblastic leukemia (BCP ALL) is a recently described childhood ALL subtype characterized by aberrant ERG protein expression and highly recurrent ERG intragenic deletions. Several studies reported a remarkably favourable outcome for ERG-related BCP-ALL despite a high incidence of apparently inauspicious IKZF1 aberrations. In this study we investigated by integrative genomic analysis the main features of the ERG-related group in a cohort of B-others BCP ALL patients enrolled in the AIEOP ALL 2000 therapeutic protocol. We report a specific microRNA and snoRNA signature that characterizes ERG-related patients with up-regulation of the miR-125b-2 cluster on chromosome 21 and several snoRNAs in the Prader-Willi locus at 15q11.2, including the orphan SNORD116 cluster. Given the current lack of parameters for a comprehensive classification we suggest toexploit the noncoding RNAs signature for differential diagnosis of ERG-related patients.
Project description:ERG-related B cell precursor acute lymphoblastic leukemia (BCP ALL) is a recently described childhood ALL subtype characterized by aberrant ERG protein expression and highly recurrent ERG intragenic deletions. Several studies reported a remarkably favourable outcome for ERG-related BCP-ALL despite a high incidence of apparently inauspicious IKZF1 aberrations. In this study we investigated by integrative genomic analysis the main features of the ERG-related group in a cohort of B-others BCP ALL patients enrolled in the AIEOP ALL 2000 therapeutic protocol. We report a specific microRNA and snoRNA signature that characterizes ERG-related patients with up-regulation of the miR-125b-2 cluster on chromosome 21 and several snoRNAs in the Prader-Willi locus at 15q11.2, including the orphan SNORD116 cluster. Given the current lack of parameters for a comprehensive classification we suggest toexploit the noncoding RNAs signature for differential diagnosis of ERG-related patients.
Project description:ERG is a transcription factor that is involved in leukomogenesis and its mRNA overexpression has been associated with poor prognosis in a subset of patients with T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Herein, a genome-wide screen of ERG target genes was conducted by chromatin immunoprecipitation-on-chip (ChIP-chip) in Jurkat cells. 342 significant annotated regions were derived from ChIP-chip experiments. Seventeen candidate promoter regions resulted in at least two-fold enrichment by quantitative PCR. Notably, ERG potential targets included WNT signaling genes: WNT2, WNT9A, WNT11, CCND1, and FZD7. Functionally, expression of WNT11 was downregulated with siRNA ERG knockdown and substantially upregulated in a tet-on ERG-inducible assay in K562 cells. To investigate a role for ERG in WNT signaling, a WNT agonist was used to inhibit glycogen synthase kinase (GSK-3). This treatment resulted in an ERG-dependent proliferative growth advantage in the tet-on ERG-inducible system. Lastly, chromatin immunoprecipitation assays of primary leukemia blasts confirmed WNT11 promoter enrichment dependent on ERG mRNA expression. In conclusion, ERG transcriptional networks in leukemia are revealed. Specifically, WNT11 emerged as a target of ERG. We propose that overexpression of ERG in acute leukemia may lead to a proliferative advantage upon activation of WNT signals. ChIP-chip with ERG antibody C20 and combined C17/20 and nonspecificic IgG in Jurkat
Project description:ERG is a transcription factor that is involved in leukomogenesis and its mRNA overexpression has been associated with poor prognosis in a subset of patients with T-cell acute lymphoblastic leukemia (T-ALL) and acute myeloid leukemia (AML). Herein, a genome-wide screen of ERG target genes was conducted by chromatin immunoprecipitation-on-chip (ChIP-chip) in Jurkat cells. 342 significant annotated regions were derived from ChIP-chip experiments. Seventeen candidate promoter regions resulted in at least two-fold enrichment by quantitative PCR. Notably, ERG potential targets included WNT signaling genes: WNT2, WNT9A, WNT11, CCND1, and FZD7. Functionally, expression of WNT11 was downregulated with siRNA ERG knockdown and substantially upregulated in a tet-on ERG-inducible assay in K562 cells. To investigate a role for ERG in WNT signaling, a WNT agonist was used to inhibit glycogen synthase kinase (GSK-3). This treatment resulted in an ERG-dependent proliferative growth advantage in the tet-on ERG-inducible system. Lastly, chromatin immunoprecipitation assays of primary leukemia blasts confirmed WNT11 promoter enrichment dependent on ERG mRNA expression. In conclusion, ERG transcriptional networks in leukemia are revealed. Specifically, WNT11 emerged as a target of ERG. We propose that overexpression of ERG in acute leukemia may lead to a proliferative advantage upon activation of WNT signals.
Project description:ERG is an Ets-transcription factor required for normal blood stem cell development. High ERG expression in acute myeloid leukemia (AML) and acute T-cell lymphoblastic leukemia (T-ALL) is associated with a stem cell signature and poor prognosis. In murine over-expression models, human ERG is a potent oncogene that induces both T-ALL and AML. However the functional and molecular consequences of high ERG expression in normal hematopoietic stem/progenitors (HSPCs), and how this contributes to leukemia development, are unknown. Here we show that retroviral transduction of ERG into human CD34+ cells and maintenance of ERG at levels present in high ERG AML results in altered myeloid and T cell differentiation and an increase in the self-renewal capacity of transduced progenitors but not the more primitive stem cell compartment. Integrated analysis of genome-wide expression in high ERG CD34+ and ERG binding profiles in HSPCs revealed that these functional characteristics were accompanied by an expression signature that was enriched in normal HSCs, high ERG AMLs, early T-cell precursor (ETP)-ALLs and leukemic stem cell signatures associated with poor clinical outcome. The proliferative advantage of high ERG progenitors may provide a cellular context for the acquisition and propagation of mutations that contribute to the pathogenesis of leukaemia. RNA sequencing in ERG overexpressing human CD34+ cells
Project description:High expression of the ETS family transcription factor ERG is associated with poor clinical outcome in acute myeloid leukemia (AML) and acute T-cell lymphoblastic leukemia (T-ALL). In murine models, high ERG expression induces both T-ALL and AML. However, no study to date has defined the effect of high ERG expression on primary human hematopoietic cells. In the present study, human CD34+ cells were transduced with retroviral vectors to elevate ERG gene expression to levels detected in high ERG AML. RNA sequencing was performed on purified populations of transduced cells to define the effects of high ERG on gene expression in human CD34+ cells. Integration of the genome-wide expression data with other data sets revealed that high ERG drives an expression signature that shares features of normal hematopoietic stem cells, high ERG AMLs, early T-cell precursor-ALLs and leukemic stem cell signatures associated with poor clinical outcome. Functional assays linked this gene expression profile to enhanced progenitor cell expansion. These results support a model whereby a stem cell gene expression network driven by high ERG in human cells enhances the expansion of the progenitor pool, providing opportunity for the acquisition and propagation of mutations and the development of leukemia.
Project description:T-cell lymphoblastic lymphoma T-LBL is a rare aggressive neoplasm of precursor T cells whose pathogenesis is not fully elucidated and it is closely related to acute lymphoblastic leukemia (T-ALL), the most common subtype of cancer in children, although recent studies suggest biological differences between the two entities.