DNA methyltransferase 3A (DNMT3A) is frequently mutated in hematological cancers; however, the underlying oncogenic mechanism remains elusive. Here, we report that DNMT3A mutational hotspot at Arg882 (DNMT3A R882H) cooperates with NRAS mutation to transform hematopoietic stem/progenitor cells and induce acute leukemia development. Mechanistically, DNMT3A R882H directly binds to and potentiates transactivation of stemness genes critical for leukemogenicity including Meis1, Mn1 and Hoxa gene cluster. DNMT3A R882H induces focal epigenetic alterations, including CpG hypomethylation and concurrent gain of active histone modifications, at cis-regulatory elements such as enhancers to facilitate gene transcription. CRISPR/Cas9-mediated ablation of a putative Meis1 enhancer carrying DNMT3A R882H-induced DNA hypomethylation impairs Meis1 expression. Importantly, DNMT3A R882H-induced gene expression programs can be repressed through Dot1l inhibition, providing an attractive therapeutic strategy for DNMT3A-mutated leukemias.
Epigenetic Perturbations by Arg882-Mutated DNMT3A Potentiate Aberrant Stem Cell Gene-Expression Program and Acute Leukemia Development.
Specimen part, Cell line, Treatment, Time
View SamplesDNA Methyltransferase 3A (DNMT3A) is frequently mutated in various hematopoietic malignancies; however, the underlying oncogenic mechanisms remain elusive. Here, we report that DNMT3A mutational hotspot at Arg882 (i.e., DNMT3A-R882H) cooperates with constitutively activated RAS in transforming murine hematopoietic stem/progenitor cells (HSPCs) ex vivo and inducing acute leukemias in vivo. DNMT3A-R882H potentiates aberrant transactivation of stemness gene expression programs, notably transcription factors Meis1, Hox-A, Mn1 and Mycn. Mechanistically, R882-mutated DNMT3A directly binds to cis-regulatory elements of these genes and induces focal CpG hypomethylation reminiscent of what was seen in human leukemias bearing DNMT3A R882 mutation. Furthermore, DNMT3A-R882H induced DNA hypomethylation facilitates gene enhancer/promoter activation and recruitment of Dot1l-associated transcription elongation machineries. Inactivation of Dot1l represses DNMT3AR882H-mediated stem cell gene dysregulation and acute leukemogenicity.
Epigenetic Perturbations by Arg882-Mutated DNMT3A Potentiate Aberrant Stem Cell Gene-Expression Program and Acute Leukemia Development.
Specimen part, Time
View SamplesDNA Methyltransferase 3A (DNMT3A) is frequently mutated in various hematopoietic malignancies; however, the underlying oncogenic mechanisms remain elusive. Here, we report that DNMT3A mutational hotspot at Arg882 (DNMT3A-R882H) cooperates with constitutively activated RAS in transforming murine hematopoietic stem/progenitor cells (HSPCs) ex vivo and inducing acute leukemias in vivo. DNMT3A-R882H potentiates aberrant transactivation of stemness gene expression programs, notably transcription factors Meis1, Hox-A, Mn1 and Mycn. Mechanistically, R882-mutated DNMT3A directly binds to cis-regulatory elements of these genes and induces focal CpG hypomethylation reminiscent of what was seen in human leukemias bearing DNMT3A R882 mutation. Furthermore, DNMT3A-R882H induced DNA hypomethylation facilitates gene enhancer/promoter activation and recruitment of Dot1l-associated transcription elongation machineries. Inactivation of Dot1l represses DNMT3AR882H-mediated stem cell gene dysregulation and acute leukemogenicity.
Epigenetic Perturbations by Arg882-Mutated DNMT3A Potentiate Aberrant Stem Cell Gene-Expression Program and Acute Leukemia Development.
Cell line, Treatment
View SamplesThe ts-p53 E285K protein is a rare p53 mutant with temperature-sensitive (ts) loss of function characteristics. In cancer cells, which express ts-p53 E285K intriniscally, endogenous wild type p53 activity is reconstituted by appropriate cultivation temperature (permissive condition). At non-appropriate cultivation temperature (restrictive condition) this p53 mutant is inactive. The present study took advantage of this mechanism and employed IPH-926 lobular breast cancer cells and BT-474 ductal breast cancer cells, which both harbor endogenous ts-p53 E285K, for the transcriptional profiling of p53-responsive genes. This new approach eliminated the need for genetic modification or cytotoxic stimulation to achive a p53 response in the cells being investigated .
IPH-926 lobular breast cancer cells harbor a p53 mutant with temperature-sensitive functional activity and allow for profiling of p53-responsive genes.
Specimen part, Cell line, Treatment
View SamplesHuman solid tumors contain rare cancer side population (SP) cells, which expel the fluorescencent dye H33342 and display cancer stem cell characteristics. Transcriptional profiling of cancer SP cells isolated by H33342 fluorescence analysis is a newly emerging approach to discover cancer stem cell markers and aberrant differentiation pathways. Using Affymetrix expression microarrays this study investigated differential gene expression between SP and non-SP (NSP) cells isolated from the CAL-51 human mammary carcinoma cell line.
Down-regulation of the fetal stem cell factor SOX17 by H33342: a mechanism responsible for differential gene expression in breast cancer side population cells.
Specimen part
View SamplesCase story. A patient with massive infiltration of the visceral adipose tissue depot by BAT in a patient with a catecholamine secreting paraganglioma. BAT tissue was identified by protein expression of UCP1 (western blotting and immunostaining)
Chronic adrenergic stimulation induces brown adipose tissue differentiation in visceral adipose tissue.
Specimen part
View SamplesThe endocytic receptor megalin constitutes the main pathway for clearance of plasma proteins from the glomerular filtrate in the proximal tubules. However, little is know about the mechanisms that control receptor activity. A widely discussed hypothesis states that the intracellular domain (ICD) of megalin, released upon ligand binding, acts as a transcription regulator to suppress receptor expression - a mechanism proposed to safeguard the proximal tubules from protein overload. Here, we have put this hypothesis to the test by generating a mouse model co-expressing the soluble ICD and the full-length receptor. Despite pronounced expression in the proximal tubules, the ICD failed to exert any effects on renal proximal tubular function such as megalin expression, protein retrieval, or renal gene transcription. Thus, our data argue that the ICD does not play a role in regulation of megalin activity in vivo in the proximal tubules.
The soluble intracellular domain of megalin does not affect renal proximal tubular function in vivo.
Sex, Age, Specimen part
View SamplesIn the present in vitro study, interactions between P. aeruginosa (sessile biofilms as well as planktonic cells) and PMNs were analyzed by means of DNA microarray based transcriptomics. We found that the P. aeruginosa wild type biofilms, in contrast to planktonic cultures and quorum sensing (QS) deficient strains, respond to PMN exposure in a rather aggressive manner. The response does not involve protective mechanisms such as those involved in oxidative stress. Rather it is dominated by QS controlled virulence determinants such as those encoded by pqs, phz, rhlAB, all of which are designed to cripple Eukaryotic cells including PMNs and macrophages. Our comparative analysis supports the view that QS plays a major role in mechanisms by which P. aeruginosa evades host defense systems.
Pseudomonas aeruginosa recognizes and responds aggressively to the presence of polymorphonuclear leukocytes.
No sample metadata fields
View SamplesBackground: Maize plants developed typical gray leaf spot disease (GLS) symptoms initiating at the lower leaves and progressing to upper leaves through the season. Leaf material was collected at 77 days after planting, at which stage there were a large number of GLS disease necrotic lesions on lower leaves (8% surface area on average determined by digital image analysis), but very few lesions and only at chlorotic stage on leaves above the ear (average of 0.2% lesion surface area). Method:To collect material that reflected a difference between C.zeina infected B73 leaves and control B73 leaf material, samples were collected from two lower GLS infected leaves (second and third leaf internode below ear) , and two upper leaves with minimal GLS symptoms (second and third internode above ear), respectively. The two lower leaves from each plant were pooled prior to RNA extraction, and the two upper leaves from each plant were pooled prior to RNA extraction. Upper and lower leaf samples from three maize B73 plants were subjected to RNA sequencing individually. The three maize plants were selected randomly as one plant per row from three rows of ten B73 plants each. Result: A systems genetics strategy revealed regions on the maize genome underlying co-expression of genes in susceptible and resistance responses, including a set of 100 genes common to the susceptible response of sub-tropical and temperate maize. Overall design: To collect material that reflected a difference between C.zeina infected B73 leaves and control B73 leaf material, samples were collected from two lower GLS infected leaves (second and third leaf internode below ear) , and two upper leaves with minimal GLS symptoms (second and third internode above ear), respectively. The two lower leaves from each plant were pooled prior to RNA extraction, and the two upper leaves from each plant were pooled prior to RNA extraction. Upper and lower leaf samples from three maize B73 plants were subjected to RNA sequencing individually. The three maize plants were selected randomly as one plant per row from three rows of ten B73 plants each.
Systems genetics reveals a transcriptional network associated with susceptibility in the maize-grey leaf spot pathosystem.
Subject
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Anti-inflammatory properties of alpha- and gamma-tocopherol.
Sex
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