We used microarrays to detail the global programme of gene expression underlying beta catenin activation in embryonic pancreas.
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Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
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Specimen part, Disease, Disease stage
View SamplesThe objective is to generate a robust and validated predictor profile for chemotherapy response in patients with mCRC using microarray gene expression profiles of primary colorectal cancer tissue.
Gene expression profile predictive of response to chemotherapy in metastatic colorectal cancer.
Disease, Disease stage
View SamplesOBJECTIVE: MEIS1, a HOX cofactor, collaborates with multiple HOX and NUP98-HOX fusion proteins to accelerate the onset of acute myeloid leukemia (AML) through largely unknown molecular mechanisms. MATERIALS AND METHODS: To further resolve these mechanisms, we conducted a structure-function analysis of MEIS1 and gene-expression profiling, in the context of NUP98-HOXD13 (ND13) leukemogenesis. RESULTS: We show, in a murine bone marrow transplantation model, that the PBX-interaction domain, the homeodomain, and the C-terminal domain of MEIS1, are all required for leukemogenic collaboration with ND13. In contrast, the N-terminal domain of MEIS1 is dispensable for collaboration with ND13, but is required for Flt3 upregulation, indicating additional roles for MEIS1 in induction of leukemia independent of alterations in Flt3 expression. Gene-expression profiling of a cloned ND13 preleukemic cell line transduced with wild-type or Meis1 mutant forms revealed deregulation of multiple genes, including a set not previously implicated as MEIS1 targets. Chromatin immunoprecipitation revealed the in vivo occupancy of MEIS1 on regulatory sequences of Trib2, Flt3, Dlk1, Ccl3, Ccl4, Pf4, and Rgs1. Furthermore, engineered overexpression of Trib2 complements ND13 to induce AML while Ccl3 potentiates the repopulating ability of ND13. CONCLUSION: This study shows that Meis1-induced leukemogenesis with ND13 can occur in the absence of Flt3 upregulation and reveals the existence of other pathways activated by MEIS1 to promote leukemia.
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Specimen part
View SamplesBACKGROUND: Hox genes are implicated in hematopoietic stem cell (HSC) regulation as well as in leukemia development through translocation with the nucleoporin gene NUP98. Interestingly, an engineered NUP98-HOXA10 (NA10) fusion can induce a several hundred-fold expansion of HSCs in vitro and NA10 and the AML-associated fusion gene NUP98-HOXD13 (ND13) have a virtually indistinguishable ability to transform myeloid progenitor cells in vitro and to induce leukemia in collaboration with MEIS1 in vivo. METHODOLOGY/PRINCIPAL FINDINGS: These findings provided a potentially powerful approach to identify key pathways mediating Hox-induced expansion and transformation of HSCs by identifying gene expression changes commonly induced by ND13 and NA10 but not by a NUP98-Hox fusion with a non-DNA binding homedomain mutation (N51S). The gene expression repertoire of purified murine bone marrow Sca-1+Lin- cells transduced with retroviral vectors encoding for these genes was established using the Affymetrix GeneChip MOE430A. Approximately seventy genes were differentially expressed in ND13 and NA10 cells that were significantly changed by both compared to the ND13(N51S) mutant. Intriguingly, several of these potential Hox target genes have been implicated in HSC expansion and self-renewal, including the tyrosine kinase receptor Flt3, the prion protein, Prnp, hepatic leukemia factor, Hlf and Jagged-2, Jag2. CONCLUSIONS: In conclusion this study has identified several novel Hox downstream target genes and provides important new leads to key regulators of the expansion and transformation of hematopoietic stem cells by Hox.
Candidate genes for expansion and transformation of hematopoietic stem cells by NUP98-HOX fusion genes.
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View SamplesThe molecular mechanism defining susceptibility of normal cells to oncogenic transformation may be a valuable therapeutic target. We characterized the cell of origin and its critical pathways in MN1 leukemias. Common myeloid (CMP), but not granulocyte-macrophage progenitors (CMP) could be transformed by constitutively overexpressed MN1. Complementation studies of CMP-signature genes in GMPs demonstrated that leukemogenicity of MN1 required the MEIS1/abdB-like HOX protein complex. Colocalization studies by ChIP-seq identified common chromatin targets of MN1 and MEIS1 that were associated with open chromatin and transcriptional activation. Transcriptional repression of MEIS1 target sites in established MN1 leukemias had antileukemic activity. As MN1 relies on but can not activate expression of MEIS1/abdB-like HOX proteins, transcriptional activity of these genes determines which cell is the cell of origin in MN1 leukemia.
Cell of origin in AML: susceptibility to MN1-induced transformation is regulated by the MEIS1/AbdB-like HOX protein complex.
Specimen part
View SamplesPhysical factors can have major influences on the proliferation and differentiation fate of hematopoietic stem cells in culture. Recently, we demonstrated that cord blood CD34+ cells undergo accelerated and increased megakaryocyte differentiation when incubated at 39C. In this study, we investigated in detail the impacts of mild hyperthermia on the kinetics of megakaryocyte differentiation, maturation, polyploidization and cell viability. The qualitative and quantitative effects on Mk differentiation were found to be rapidly induced, and optimization of the culture length at 39C led to greater Mk yields. Mild hyperthermia did not promote endomitosis of cord blood-derived Mk, but rather led to a small reduction in the proportion of polyploid Mk. Moreover, it had little impact on viability but induced a significant shift in the proportion of cells undergoing apoptosis at 37C to necrosis at 39C. Finally, our results suggest that the effects on megakaryocyte differentiation could be the consequences of aberrant expression of key megakaryocyte transcription factors induced by mild hyperthermia.
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View SamplesIschemia, fibrosis, and remodeling lead to heart failure after severe myocardial infarction (MI). Myoblast sheet transplantation is a promising therapy to enhance cardiac function and induce therapeutic angiogenesis via a paracrine mechanism in this detrimental disease. We hypothesized that in a rat model of MI-induced chronic heart failure this therapy could further be improved by overexpression of the antiapoptotic, antifibrotic, and proangiogenic hepatocyte growth factor (HGF) in the myoblast sheets. We studied the ability of wild type (L6-WT) and human HGF-expressing (L6-HGF) L6 myoblast sheet-derived paracrine factors to stimulate cardiomyocyte, endothelial cell, or smooth muscle cell migration in culture. Further, we studied the autocrine effect of hHGF-expression on myoblast gene expression using microarray analysis. We induced MI in Wistar rats by left anterior descending coronary artery (LAD) ligation and allowed heart failure to develop for four weeks. Thereafter, we administered L6-WT (n=15) or L6-HGF (n=16) myoblast sheet therapy. Control rats (n=13) underwent LAD ligation and rethoracotomy without therapy and five rats underwent sham-operation in both surgeries. We evaluated cardiac function with echocardiography at 2 and 4 weeks after therapy administration. We analyzed cardiac angiogenesis and left ventricular architecture from histological sections 4 weeks after therapy. Paracrine mediators from L6-HGF myoblast sheets effectively induced migration of cardiac endothelial and smooth muscle cells but not cardiomyocytes. Microarray data revealed that hHGF-expression modulated myoblast gene expression. In vivo, L6-HGF sheet therapy effectively stimulated angiogenesis in the infarcted and non-infarcted areas. Both L6-WT and L6-HGF therapies enhanced cardiac function and inhibited remodeling in a similar fashion. In conclusion, L6-HGF therapy effectively induced angiogenesis in the chronically failing heart. Cardiac function, however, was not further enhanced by hHGF-expression.
hHGF overexpression in myoblast sheets enhances their angiogenic potential in rat chronic heart failure.
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View SamplesTo study the effect of myoblast-derived paracrine factors on cardiomyocyte gene expression, microarray analysis was performed from isolated rat fetal cardiomyocyte cultures. These cultures were treated for 24 hours with fresh culture medium (control), skeletal myoblast-conditioned medium, or cardiac fibroblast-conditioned medium.
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Specimen part, Treatment
View SamplesPmr1 is a cis-Golgi Mn/Ca transporter with a key role in protein glycosylation and manganese detoxification.
Manganese redistribution by calcium-stimulated vesicle trafficking bypasses the need for P-type ATPase function.
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