This SuperSeries is composed of the SubSeries listed below.
Role of SWI/SNF in acute leukemia maintenance and enhancer-mediated Myc regulation.
Specimen part, Cell line, Treatment
View SamplesEpigenetic pathways regulate gene expression by controlling and interpreting chromatin modifications. Cancer cells are characterized by altered epigenetic landscapes and commonly exploit the chromatin regulatory machinery to enforce oncogenic gene expression programs. While chromatin alterations are, in principle, reversible and often amendable to drug intervention, the promise of targeting such pathways therapeutically has been hampered by our limited understanding of cancer-specific epigenetic dependencies. Here we describe a non-biased approach to probe epigenetic vulnerabilities in acute myeloid leukemia (AML) an aggressive hematopoietic malignancy often associated with aberrant chromatin states. By screening a custom shRNA library targeting known chromatin regulators in a genetically defined AML mouse model, we identify the bromodomain-containing protein Brd4 as a critical requirement for disease maintenance. Suppression of Brd4 using shRNAs or the small-molecule inhibitor JQ1 led to robust anti-leukemic effects in vitro and in vivo, accompanied by terminal myeloid differentiation. Extensive evaluation of JQ1-sensitivity in primary human leukemia samples and in established cell lines revealed a broad activity of this compound against diverse AML subtypes. These effects are, at least in part, due to a requirement for Brd4 in maintaining Myc expression and promoting aberrant self-renewal. Together, our results indicate that Brd4 is a promising therapeutic target in AML and identify a small molecule that efficiently targets Myc. These findings also highlight the utility of RNAi screening as a discovery platform for revealing epigenetic vulnerabilities for direct pharmacologic intervention in cancer.
RNAi screen identifies Brd4 as a therapeutic target in acute myeloid leukaemia.
Cell line, Treatment
View SamplesThe transcriptional activating and repressive functions performed by Trithorax and Polycomb group complexes, respectively, are critical for to maintain cellular fates in ontogeny and in cancer. Here we report that leukemias initiated by a Trithorax-related oncogene, MLL-AF9, depend upon the Polycomb Repressive Complex 2 (PRC2) to sustain a transformed cellular state. RNAi mediated suppression of PRC2 subunits is sufficient to inhibit proliferation of MLL-AF9 leukemias, with little impact on growth of non-transformed cells. This requirement is partly due to PRC2-mediated transcriptional repression of several anti-self-renewal regulators, including Cdkn2a. These results suggest that, unlike the classical antagonism generally observed between Polycomb and Trithorax group proteins during development, the activities of these two pathways can cooperate to promote myeloid neoplasia.
The Polycomb complex PRC2 supports aberrant self-renewal in a mouse model of MLL-AF9;Nras(G12D) acute myeloid leukemia.
No sample metadata fields
View SamplesCancer cells frequently depend on chromatin regulatory activities to maintain a malignant phenotype. Here, we show that leukemia cells require the mammalian SWI/SNF chromatin remodeling complex for their survival and aberrant self-renewal potential. While Brg1, an ATPase subunit of SWI/SNF, is known to suppress tumor formation in several cancer types, we found that leukemia cells instead rely on Brg1 to support their oncogenic transcriptional program, which includes Myc as one of its key targets. To account for this context-specific function, we identify a cluster of lineage-specific enhancers located 1.7 megabases downstream of Myc that are occupied by SWI/SNF, as well as the BET protein Brd4. Brg1 is required at these distal elements to maintain transcription factor occupancy and for long-range chromatin looping interactions with the Myc promoter. Notably, these distal Myc enhancers coincide with a region that is focally amplified in 3% of acute myeloid leukemia. Together, these findings define a leukemia maintenance function for SWI/SNF that is linked to enhancer-mediated gene regulation, providing general insights into how cancer cells exploit transcriptional coactivators to maintain oncogenic gene expression programs
Role of SWI/SNF in acute leukemia maintenance and enhancer-mediated Myc regulation.
Specimen part, Cell line
View SamplesWe have established that BMP6 is an important endogenous regulator of human osteoblast differentiation. Our preliminary experiment showed that 8 hour BMP6 treatment induced early osteoblast markers in hMSC.
GAGE: generally applicable gene set enrichment for pathway analysis.
No sample metadata fields
View SamplesEzh2 encodes for the catalyc unit of the PRC2 complex. RNAi-mediated suppressing of Ezh2 by two independent shRNAs promotes Em-myc lymphomagenesis in vivo.
No associated publication
Specimen part, Treatment
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Identification of tumor suppressors and oncogenes from genomic and epigenetic features in ovarian cancer.
Sex, Disease, Disease stage, Treatment
View SamplesWeve undertaken a genome-wide approach to identify and test genes in fibroblasts that are both induced upon interaction with basal breast cancer cells in culture and upregulated in stromal cells from primary human breast cancers. Several of the upregulated genes encode secreted growth factors or cytokines. Using RNAi and a co-injection tumorigenicity assay, we determined that the majority of secreted factors selected for functional validation played significant, yet functionally diverse, roles in promoting tumorigenicity. Rather than a single major mediator, these results indicate multiple points of intervention to prevent fibroblasts from supporting basal breast cancer. Additionally, we show that breast cancer subtypes differ markedly in the expression of these and other stromally secreted proteins using data from microdissected stromal samples.
System-wide analysis reveals a complex network of tumor-fibroblast interactions involved in tumorigenicity.
No sample metadata fields
View SamplesThe identification of genetic and epigenetic alterations from primary tumor cells has become a common method to identify genes critical to the development and progression of cancer. We provide a bioinformatic analysis of copy number variation and DNA methylation covering the genetic landscape of ovarian cancer tumor cells. We individually examined the copy number variation and DNA methylation for 44 primary ovarian cancer samples and 7 ovarian normal samples using our MOMA-ROMA technology and Affymetrix expression data as well as 379 tumor samples analyzed by The Cancer Genome Atlas. We have identified 346 genes with significant deletions or amplifications among the tumor samples. Utilizing associated gene expression data we predict 156 genes with significantly altered copy number and correlated changes in expression. We identify changes in DNA methylation and expression for all amplified and deleted genes. We predicted 615 potential oncogenes and tumor suppressors candidates by integrating these multiple genomic and epigenetic data types.
Identification of tumor suppressors and oncogenes from genomic and epigenetic features in ovarian cancer.
Sex, Disease, Disease stage
View SamplesThe assembly of neural circuits involves multiple sequential steps such as the specification of cell types, their migration to proper brain locations, morphological and physiological differentiation, and the formation and maturation of synaptic connections. This intricate and often prolonged process is guided by elaborate genetic mechanisms that regulate each developmental event. Evidence from numerous systems suggests that each cell type, once specified, is endowed with a genetic program that directs its subsequent development. This cell intrinsic program unfolds in respond to, and is regulated by, extrinsic signals, including cell-cell and synaptic interactions. To a large extent, the execution of this genetic program is achieved by the expression of specific sets of genes that support distinct developmental processes. Therefore, a comprehensive analysis of the developmental progression of gene expression in synaptic partners of neurons may provide a basis for exploring the genetic mechanisms regulating circuit assembly.
Developmental Coordination of Gene Expression between Synaptic Partners During GABAergic Circuit Assembly in Cerebellar Cortex.
Sex, Specimen part
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