Homo sapiens
Ontology highlight
ABSTRACT:
PROVIDER: PRJNA172840 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:MLL-AF4 is a hallmark genomic aberration which arises prenatally in high-risk infant acute lymphoblastic leukemia (ALL). In human embryonic stem cells (hESCs), MLL-AF4 skewed hemato-endothelial specification but was not sufficient for transformation. Additional cooperating genetic insults seem required for MLL-AF4-mediated leukemogenesis. FLT3 is highly expressed in MLL-AF4+ ALL through activating mutations (FLT3-TKD or FLT3-ITD) or increased transcriptional expression, being therefore considered a potential cooperating event in MLL-AF4+ ALL. Here, we explored the developmental impact of FLT3 activation on its own or in cooperation with MLL-AF4 in the hematopoietic fate of hESCs. FLT3 activation did not impact specification of CD45-CD31+ hemogenic precursors but significantly enhanced the formation of CD45+CD34+ and CD45+ blood cells and blood progenitors with clonogenic potential. Importantly, FLT3 activation through FLT3 mutations or FLT3-WT overexpression completely abrogated hematopoietic differentiation from MLL-AF4-expressing hESCs, indicating that FLT3 activation cooperates with MLL-AF4 to inhibit human embryonic hematopoiesis. Cell cycle/apoptosis analyses suggest that FLT3 activation directly impacts hESC specification rather than selective proliferation/survival of hESC-emerging hematopoietic derivatives. Transcriptional profiling supported the limited impact of FLT3 activation on hESC specification towards CD45-hemogenic precursors and the enhanced hematopoiesis upon FLT3 activation, and inhibited hematopoiesis upon MLL-AF4 expression in FLT3-activated hESCs which was associated to large transcriptional changes and regulation of master early hematopoietic genes. Also, although FLT3 activation and MLL-AF4 cooperate to inhibit embryonic hematopoiesis the underlying molecular/genetic mechanisms differ depending on how FLT3 activation is achieved. Finally, FLT3 activation did not cooperate with MLL-AF4 to immortalize/transform hESC-derived hematopoietic cells. 18 samples were analyzed. CD45- hemogenic precursors EV, 2 biological rep CD45- hemogenic precursors FLT3-TKD, 2 biological rep CD45- hemogenic precursors FLT3-WT, 2 biological rep CD45- hemogenic precursors FLT3-TKD/MLLAF4, 2 biological rep CD45- hemogenic precursors FLT3-WT/MLLAF4, 2 biological rep CD45+ blood cells EV, 1 biological rep CD45+ blood cells FLT3-TKD, 2 biological rep CD45+ blood cells FLT3-WT, 2 biological rep CD45+ blood cells FLT3-TKD/MLLAF4, 2 biological rep CD45+ blood cells FLT3-WT/MLLAF4, 1 biological rep
2013-06-04 | E-GEOD-40103 | biostudies-arrayexpress
Project description:MLL-AF4 is a hallmark genomic aberration which arises prenatally in high-risk infant acute lymphoblastic leukemia (ALL). In human embryonic stem cells (hESCs), MLL-AF4 skewed hemato-endothelial specification but was not sufficient for transformation. Additional cooperating genetic insults seem required for MLL-AF4-mediated leukemogenesis. FLT3 is highly expressed in MLL-AF4+ ALL through activating mutations (FLT3-TKD or FLT3-ITD) or increased transcriptional expression, being therefore considered a potential cooperating event in MLL-AF4+ ALL. Here, we explored the developmental impact of FLT3 activation on its own or in cooperation with MLL-AF4 in the hematopoietic fate of hESCs. FLT3 activation did not impact specification of CD45-CD31+ hemogenic precursors but significantly enhanced the formation of CD45+CD34+ and CD45+ blood cells and blood progenitors with clonogenic potential. Importantly, FLT3 activation through FLT3 mutations or FLT3-WT overexpression completely abrogated hematopoietic differentiation from MLL-AF4-expressing hESCs, indicating that FLT3 activation cooperates with MLL-AF4 to inhibit human embryonic hematopoiesis. Cell cycle/apoptosis analyses suggest that FLT3 activation directly impacts hESC specification rather than selective proliferation/survival of hESC-emerging hematopoietic derivatives. Transcriptional profiling supported the limited impact of FLT3 activation on hESC specification towards CD45-hemogenic precursors and the enhanced hematopoiesis upon FLT3 activation, and inhibited hematopoiesis upon MLL-AF4 expression in FLT3-activated hESCs which was associated to large transcriptional changes and regulation of master early hematopoietic genes. Also, although FLT3 activation and MLL-AF4 cooperate to inhibit embryonic hematopoiesis the underlying molecular/genetic mechanisms differ depending on how FLT3 activation is achieved. Finally, FLT3 activation did not cooperate with MLL-AF4 to immortalize/transform hESC-derived hematopoietic cells.
2013-06-04 | GSE40103 | GEO
Project description:The MLL-AF4 fusion gene is a hallmark genomic aberration in high-risk acute lymphoblastic leukemia in infants. Although it is well-established that MLL-AF4 arises pre-natally during human development, its effects on hematopoietic development in utero remains unexplored. We have created a human-specific in vitro system to study early hemato-endothelial development in MLL-AF4-expressing human embryonic stem cells (hESCs). Differentiation and functional studies as well as clonal analyses and gene expression profiling reveal that expression of MLL-AF4 in hESCs has a phenotypic, functional and gene expression impact. It enhances the specification of hemogenic precursors from hESCs and impairs further hematopoietic commitment of these precursors in favour of the endothelial cell fate. Similar to that reported in cord blood CD34+ hematopoietic stem/progenitor cells (HSPCs), MLL-AF4 expression is not sufficient to transform hESC-derived hematopoietic cells in vitro or in vivo, indicating that additional events may be required to initiate leukemogenesis or that embryonic hematopoiesis is not the appropriate human cellular target for MLL-AF4-mediated leukemogenesis. This work illustrates how hESCs can provide unique insights into human development and further our understanding of how leukemic fusion genes known to arise pre-natally regulate human embryonic hematopoietic specification. MLL is involved in transcriptional regulation and most MLL translocations appear to result in increased expression of Hox genes and hematopoietic genes. We therefore assessed the impact of MLL-AF4 expression on the transcriptome of hESCs. Gene expression profiling performed in MLL-AF4 hESCs revealed that MLL-AF4 preferentially activates transcription. 1826 out of the 3001 genes (61%) expressed were up-regulated in MLL-AF4 hESCs. Human ESC samples were collected during the exponential cell growth phase and stabilized in RNA later. 500 ng of each total RNA sample was labelled with Cy3 using the Quick-Amp Labelling kit and hybridized with the Gene Expression Hybridization kit to a Whole Human Genome Oligo Microarray (Agilent Technologies) following the Manufacturer’s instructions. Each cell line was analyzed as independent duplicates. NEO-expressing (empty lentivector) hESC line was used as the baseline.
2011-06-09 | E-GEOD-29869 | biostudies-arrayexpress
Project description:The MLL-AF4 fusion gene is a hallmark genomic aberration in high-risk acute lymphoblastic leukemia in infants. Although it is well-established that MLL-AF4 arises pre-natally during human development, its effects on hematopoietic development in utero remains unexplored. We have created a human-specific in vitro system to study early hemato-endothelial development in MLL-AF4-expressing human embryonic stem cells (hESCs). Differentiation and functional studies as well as clonal analyses and gene expression profiling reveal that expression of MLL-AF4 in hESCs has a phenotypic, functional and gene expression impact. It enhances the specification of hemogenic precursors from hESCs and impairs further hematopoietic commitment of these precursors in favour of the endothelial cell fate. Similar to that reported in cord blood CD34+ hematopoietic stem/progenitor cells (HSPCs), MLL-AF4 expression is not sufficient to transform hESC-derived hematopoietic cells in vitro or in vivo, indicating that additional events may be required to initiate leukemogenesis or that embryonic hematopoiesis is not the appropriate human cellular target for MLL-AF4-mediated leukemogenesis. This work illustrates how hESCs can provide unique insights into human development and further our understanding of how leukemic fusion genes known to arise pre-natally regulate human embryonic hematopoietic specification.
2011-06-09 | GSE29869 | GEO
Project description:The tumorigenesis capacity of MLL-AF4 alone is insufficient for causing leukemia. Based on the finding that an Flt3 gene mutation in the tyrosine kinase domain (TKD) was observed in approximately 15% of MLL leukemia, we investigated synergistic leukemogenesis effects of the two genes in vitro. In a mouse IL3-dependent cell line, 32Dc, the expression of MLL-AF4 and Flt3 TKD was induced using a lentiviral vector. We performed gene expression profiling in the MLL-AF4 and the Flt3 TKD+MLL-AF4 expressing 32Dc cells. The enhancement of Hox genes expression was not identified. However, instead, the expression of S100A6, which was involved in the control of cell proliferation, was synergistically enhanced in the presence of both MLL-AF4 and Flt3 TKD genes. We performed gene expression profiling: 32Dc vs. MLL-AF4 expressing 32Dc, 32Dc vs. Flt3 TKD+MLL-AF4 expressing 32Dc, and MLL-AF4 expressing 32Dc vs. Flt3 TKD+MLL-AF4 expressing 32Dc. A single sample for each expressing cells was analyzed.
2009-03-31 | E-GEOD-14236 | biostudies-arrayexpress
Project description:MLL-fusion proteins are potent inducers of cancer in hematopoietic cells, where they are known to cause changes in global gene expression. How MLL-fusion proteins interact with the genome has not been established, so we have limited understanding of the pathway by which these proteins generate aberrant gene expression programs. Here we describe how the MLL-AF4 protein occupies the genome in human leukemia cells and its striking effects on chromatin states. We find that the MLL-AF4 fusion protein selectively occupies regions of the genome that contain developmental regulatory genes important for hematopoietic stem cell identity and self-renewal. These MLL-AF4 bound regions have grossly altered chromatin structure, with histone modifications catalyzed by Trithorax Group (TrxG) proteins and Dot1 extending across unusually large domains. This indicates that a key feature of MLL-associated leukemogenesis is aberrant targeting of chromatin modifiers to regions of the genome controlling hematopoietic development. Our results define the direct targets of the MLL-fusion protein, reveal the global role of epigenetic misregulation in leukemia, and identify new targets for therapeutic intervention in human cancer. Keywords: cell type comparison This dataset includes expression data for two replicates each of SEM and REH leukemia cell lines and ChIP-chip data targeting RNAP2, H3K4me3, H3K79me2, ENL, AF4-C, and MLL-N in SEM and REH leukemia cell lines.
2008-12-14 | E-GEOD-13313 | biostudies-arrayexpress
Project description:MLL-fusion proteins are potent inducers of cancer in hematopoietic cells, where they are known to cause changes in global gene expression. How MLL-fusion proteins interact with the genome has not been established, so we have limited understanding of the pathway by which these proteins generate aberrant gene expression programs. Here we describe how the MLL-AF4 protein occupies the genome in human leukemia cells and its striking effects on chromatin states. We find that the MLL-AF4 fusion protein selectively occupies regions of the genome that contain developmental regulatory genes important for hematopoietic stem cell identity and self-renewal. These MLL-AF4 bound regions have grossly altered chromatin structure, with histone modifications catalyzed by Trithorax Group (TrxG) proteins and Dot1 extending across unusually large domains. This indicates that a key feature of MLL-associated leukemogenesis is aberrant targeting of chromatin modifiers to regions of the genome controlling hematopoietic development. Our results define the direct targets of the MLL-fusion protein, reveal the global role of epigenetic misregulation in leukemia, and identify new targets for therapeutic intervention in human cancer. This dataset includes expression data for two replicates each of SEM and REH leukemia cell lines, ChIP-chip data targeting RNAP2, H3K4me3, H3K79me2, ENL, AF4-C, and MLL-N in SEM and REH leukemia cell lines, and ChIP-Seq data of H3K79me2, H3K4me3, ans WCE in SEM and REH cell lines. This Series contains the ChIP-Seq data only. The expression and ChIP-chip data are provided in GEO Series GSE13313.
2012-05-31 | E-GEOD-38338 | biostudies-arrayexpress
Project description:The tumorigenesis capacity of MLL-AF4 alone is insufficient for causing leukemia. Based on the finding that an Flt3 gene mutation in the tyrosine kinase domain (TKD) was observed in approximately 15% of MLL leukemia, we investigated synergistic leukemogenesis effects of the two genes in vitro. In a mouse IL3-dependent cell line, 32Dc, the expression of MLL-AF4 and Flt3 TKD was induced using a lentiviral vector. We performed gene expression profiling in the MLL-AF4 and the Flt3 TKD+MLL-AF4 expressing 32Dc cells. The enhancement of Hox genes expression was not identified. However, instead, the expression of S100A6, which was involved in the control of cell proliferation, was synergistically enhanced in the presence of both MLL-AF4 and Flt3 TKD genes.
2009-03-31 | GSE14236 | GEO
Project description:MLL-fusion proteins are potent inducers of cancer in hematopoietic cells, where they are known to cause changes in global gene expression. How MLL-fusion proteins interact with the genome has not been established, so we have limited understanding of the pathway by which these proteins generate aberrant gene expression programs. Here we describe how the MLL-AF4 protein occupies the genome in human leukemia cells and its striking effects on chromatin states. We find that the MLL-AF4 fusion protein selectively occupies regions of the genome that contain developmental regulatory genes important for hematopoietic stem cell identity and self-renewal. These MLL-AF4 bound regions have grossly altered chromatin structure, with histone modifications catalyzed by Trithorax Group (TrxG) proteins and Dot1 extending across unusually large domains. This indicates that a key feature of MLL-associated leukemogenesis is aberrant targeting of chromatin modifiers to regions of the genome controlling hematopoietic development. Our results define the direct targets of the MLL-fusion protein, reveal the global role of epigenetic misregulation in leukemia, and identify new targets for therapeutic intervention in human cancer.
2012-05-31 | GSE38338 | GEO
Project description:MLL/AF4 fusion transcript knock-down time course in the MLL/AF4-positive B-cell precursor ALL cell line SEM using MLL/AF4 fusion site-specific siRNAs (siMLL/AF4). The aim was to identify genes responsive to MLL/AF4 expression modulation.
2018-07-21 | GSE71140 | GEO