Project description:Background: The transcription factor EVI1 regulates cellular proliferation, differentiation, and apoptosis, and contributes to an aggressive course of disease in myeloid leukemias and other malignancies. Notwithstanding, knowledge about the target genes mediating its biological and pathological functions remains limited. We therefore aimed to identify and characterize novel EVI1 target genes in human myeloid cells. Methods: U937T_EVI1, a previously established human myeloid cell line expressing EVI1 in a tetracycline regulable manner, was subjected to genome wide gene expression microarray analysis. qRT-PCR was used to confirm the regulation of MS4A3 by EVI1. Reporter constructs containing various parts of the MS4A3 upstream region were employed in luciferase assays, and direct binding of EVI1 to the MS4A3 promoter was investigated by chromatin immunoprecipitation. U937 derivative cell lines experimentally expressing EVI1 and/or MS4A3 were generated by retroviral transduction, and tested for their tumorigenicity by subcutaneous injection into severe combined immunodeficient mice. Experimental results were tested for statistical significance using ANOVA and Student's t-test (two-tailed). Results: Gene expression microarray analysis identified 27 unique genes that were up-regulated and 29 that were down-regulated in response to EVI1 induction in the human myeloid cell line, U937. The most strongly repressed gene was membrane-spanning-4-domains subfamily-A member-3 (MS4A3), and its down-regulation by EVI1 was confirmed by qRT-PCR in additional, independent experimental model systems. Reporter gene assays and chromatin immunoprecipitation showed that EVI1 regulated MS4A3 via direct binding to a promoter proximal region. Experimental re-expression of MS4A3 in an EVI1 overexpressing cell line counteracted the tumor promoting effect of EVI1 in a murine xenograft model. Conclusions: Our data reveal MS4A3 as a novel direct target of EVI1 in human myeloid cells, and show that its repression plays a role in EVI1 mediated tumor aggressiveness. Time course of 2 biological replicates, plus 2 control samples; 20 arrays in total
Project description:Background: The transcription factor EVI1 regulates cellular proliferation, differentiation, and apoptosis, and contributes to an aggressive course of disease in myeloid leukemias and other malignancies. Notwithstanding, knowledge about the target genes mediating its biological and pathological functions remains limited. We therefore aimed to identify and characterize novel EVI1 target genes in human myeloid cells. Methods: U937T_EVI1, a previously established human myeloid cell line expressing EVI1 in a tetracycline regulable manner, was subjected to genome wide gene expression microarray analysis. qRT-PCR was used to confirm the regulation of MS4A3 by EVI1. Reporter constructs containing various parts of the MS4A3 upstream region were employed in luciferase assays, and direct binding of EVI1 to the MS4A3 promoter was investigated by chromatin immunoprecipitation. U937 derivative cell lines experimentally expressing EVI1 and/or MS4A3 were generated by retroviral transduction, and tested for their tumorigenicity by subcutaneous injection into severe combined immunodeficient mice. Experimental results were tested for statistical significance using ANOVA and Student's t-test (two-tailed). Results: Gene expression microarray analysis identified 27 unique genes that were up-regulated and 29 that were down-regulated in response to EVI1 induction in the human myeloid cell line, U937. The most strongly repressed gene was membrane-spanning-4-domains subfamily-A member-3 (MS4A3), and its down-regulation by EVI1 was confirmed by qRT-PCR in additional, independent experimental model systems. Reporter gene assays and chromatin immunoprecipitation showed that EVI1 regulated MS4A3 via direct binding to a promoter proximal region. Experimental re-expression of MS4A3 in an EVI1 overexpressing cell line counteracted the tumor promoting effect of EVI1 in a murine xenograft model. Conclusions: Our data reveal MS4A3 as a novel direct target of EVI1 in human myeloid cells, and show that its repression plays a role in EVI1 mediated tumor aggressiveness.
Project description:The EVI1 gene codes for a transcription factor with important roles in development and leukemogenesis. Overexpression of EVI1 in acute myeloid leukemia (AML) is one of the worst prognostic factors in patients with and without 3q26 rearrangements. Evi1 acts in several pathways through the interaction with proteins with important functions in hematopoiesis; however, the role of Evi1 as a transcription factor is not well known, and only some Evi1 target genes have been identified in mice. Our aim was to investigate the pathways and direct target genes of EVI1. Differential expression profiles after EVI1 knockdown allowed us to identify 125 genes involved in cell growth, differentiation and signal transduction that could be related to EVI1. Moreover, we looked for potential EVI1 binding sites within the region 1000 bp upstream of the transcription start sites of all human genes. We selected a total of 70 genes from the bioinformatics search, genes related to EVI1 by literature, and genes differentially expressed in the expression array. ChIP in the TF1 and HEL cell lines with two EVI1 antibodies demonstrated that EVI1 binds to the proximal promoter regions of 18 of these genes, most of them involved in important differentiation and proliferation pathways, confirming the important role of EVI1. Interestingly, EVI1 binds to the proximal region of its promoter, suggesting that it could be regulating its own transcription. Further functional studies are in progress. These data provide a starting point for further studies aimed at uncovering the mechanism for EVI1-induced transformation leukemias. Keywords: Gene expression analysis after transient knockdown of EVI1. 12 samples. Three replicates per experimental condition. Two cell lines (HTB-58, TF-1). Transient EVI1 knockdown using anti-EVI1 siRNA molecules vs. control siRNA.
Project description:EVI1 is one of the famous poor prognostic markers for a chemotherapy-resistant acute myeloid leukemia (AML). To identify molecular targets on the surface of leukemia cells with EVI1high expression, we compared the gene expression profiles of several AML cell lines by DNA microarray To search for novel molecular targets in refractory myeloid leukemia with high EVI1 expression, we initially analyzed the gene expression profiles of 12 human myeloid cell lines. Four cell lines with chromosome 3q26 abnormalities (UCSD/AML1, HNT-34, Kasumi-3 and MOLM-1) expressed EVI1High, and eight myeloid cell lines without chromosome 3q26 abnormalities (HEL, HL-60, K052, THP-1, FKH-1, K051, NH and OIH-1) expressed low levels of EVI1 (EVI1Low)
Project description:We studied the variations of mRNA amounts after Flag-EVI1, Flag-EVI1?324, or Flag expression in HeLa cells. Despites EVI1 discovery in 1988, its recognized role as a dominant oncogene in myeloid leukemia and more recently in epithelial cancers, only a few target genes were known and it was not clear why EVI1 was involved in cancer progression. Here we obtained the genomic binding occupancy and expression data for EVI1 in human cells. We identified numerous EVI1 target cancer genes and genes controlling cell migration and adhesion. Moreover, we characterized a transcriptional cooperation between AP1 and EVI1 that regulated proliferation and adhesion through a feed-forward loop. This study provides human genome-wide mapping and expression analyses for EVI1 that will be useful for the research community. 12 samples were collected. Each condition was done in 4 replicates, collected 24 hours after transfection (for mild expression of EVI1 or EVI1?324). Transfections with Flag-expressing vector were used as controls.
Project description:We studied the variations of mRNA amounts after Flag-EVI1 or Flag expression in HeLa cells. Despites EVI1 discovery in 1988, its recognized role as a dominant oncogene in myeloid leukemia and more recently in epithelial cancers, only a few target genes were known and it was not clear why EVI1 was involved in cancer progression. Here we obtained the genomic binding occupancy and expression data for EVI1 in human cells. We identified numerous EVI1 target cancer genes and genes controlling cell migration and adhesion. Moreover, we characterized a transcriptional cooperation between AP1 and EVI1 that regulated proliferation and adhesion through a feed-forward loop. Furthermore, this study provides human genome-wide mapping and downstream analyses for EVI1 that will be useful for the research community. 8 samples were collected. Each condition was done in 4 replicates, collected 24 hours after transfection (for mild expression of EVI1). Transfections with Flag-expressing vector were used as controls.
Project description:We studied the variations of mRNA amounts after Evi1 knockdown or Flag-Evi1 overexpression in SKOV-3 cells. Despites Evi1 discovery in 1988, its recognized role as a dominant oncogene in myeloid leukemia and more recently in epithelial cancers, only a few target genes were known and it was not clear why Evi1 was involved in cancer progression. Here we obtained the genomic binding occupancy and expression data for Evi1 in human ovarian carcinoma cells. We identified numerous Evi1 target cancer genes and genes controlling cell migration and adhesion. Moreover, we characterized a transcriptional cooperation between AP1 and Evi1 that regulated proliferation and adhesion through a feed-forward loop. Furthermore, this study provides human genome-wide mapping and downstream analyses for Evi1 that will be useful for the research community. 16 samples were collected. Each condition was done in 4 replicates, collected 65 hours after transfection. Transfections with control siRNA or Flag-expressing vector were used as controls.
Project description:The EVI1 gene codes for a transcription factor with important roles in development and leukemogenesis. Overexpression of EVI1 in acute myeloid leukemia (AML) is one of the worst prognostic factors in patients with and without 3q26 rearrangements. Evi1 acts in several pathways through the interaction with proteins with important functions in hematopoiesis; however, the role of Evi1 as a transcription factor is not well known, and only some Evi1 target genes have been identified in mice. Our aim was to investigate the pathways and direct target genes of EVI1. Differential expression profiles after EVI1 knockdown allowed us to identify 125 genes involved in cell growth, differentiation and signal transduction that could be related to EVI1. Moreover, we looked for potential EVI1 binding sites within the region 1000 bp upstream of the transcription start sites of all human genes. We selected a total of 70 genes from the bioinformatics search, genes related to EVI1 by literature, and genes differentially expressed in the expression array. ChIP in the TF1 and HEL cell lines with two EVI1 antibodies demonstrated that EVI1 binds to the proximal promoter regions of 18 of these genes, most of them involved in important differentiation and proliferation pathways, confirming the important role of EVI1. Interestingly, EVI1 binds to the proximal region of its promoter, suggesting that it could be regulating its own transcription. Further functional studies are in progress. These data provide a starting point for further studies aimed at uncovering the mechanism for EVI1-induced transformation leukemias. Keywords: Gene expression analysis after transient knockdown of EVI1.