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.
Aberrant chromatin at genes encoding stem cell regulators in human mixed-lineage leukemia.
No sample metadata fields
View SamplesCD24 is a potential oncogene reported to be overexpressed in a large variety of human malignancies. We have shown that CD24 is overexpressed in 90% of colorectal tumors at a fairly early stage in the multistep process of carcinogenesis. Anti-CD24 monoclonal antibodies (mAb) induce a significant growth inhibition in colorectal and pancreatic cancer cell lines that express the protein. This study is designed to investigate further the effects of CD24 down-regulation using mAb or small interfering RNA in vitro and in vivo. Western blot analysis showed that anti-CD24 mAb induced CD24 protein down-regulation through lysosomal degradation. mAb augmented growth inhibition in combination with five classic chemotherapies. Xenograft models in vivo showed that tumor growth was significantly reduced in mAb-treated mice. Similarly, stable growth inhibition of cancer cell lines was achieved by down-regulation of CD24 expression using short hairpin RNA (shRNA). The produced clones proliferated more slowly, reached lower saturation densities, and showed impaired motility. Most importantly, down-regulation of CD24 retarded tumorigenicity of human cancer cell lines in nude mice. Microarray analysis revealed a similar pattern of gene expression alterations when cells were subjected to anti-CD24 mAb or shRNA. Genes in the Ras pathway, mitogenactivated protein kinase, or BCL-2 family and others of oncogenic association were frequently down-regulated. As a putative new oncogene that is overexpressed in gastrointestinal malignancies early in the carcinogenesis process, CD24 is a potential target for early intervention in the prevention and treatment of cancer.
Targeting CD24 for treatment of colorectal and pancreatic cancer by monoclonal antibodies or small interfering RNA.
Specimen part, Cell line
View SamplesExpression data from LEOPARD Syndrome-iPS clones, BJ-iPS cells and parental Fibroblasts
Patient-specific induced pluripotent stem-cell-derived models of LEOPARD syndrome.
Sex, Specimen part, Subject
View SamplesCompared differentially express genes by sex in mouse for the following tissues: hypothalamus, liver, kidney, ovaries and testis (3 biological x 2 technical replicates for each tissues/sex). We used Affymetrix MOE430A Genechip arrays.
Major molecular differences between mammalian sexes are involved in drug metabolism and renal function.
Sex, Specimen part
View Samples.
AlleleSeq: analysis of allele-specific expression and binding in a network framework.
No sample metadata fields
View SamplesWe examined genome-wide variation in transcription factor binding in different individuals and a chimpanzee using chromatin immunoprecipitation followed by massively-parallel sequencing (ChIP-Seq). The binding sites of RNA Polymerase II (Pol II) as well as a key regulator of immune responses, NFkB, were mapped in ten HapMap lymphoblastoid cell lines derived from individuals of African, European, and Asian ancestry, including a parent-offspring trio. We also mapped gene expression in all ten human cell lines for two treatment conditions: a) no treatment and b) following induction by TNF-alpha. Overall design: Genome-wide comparison of Pol II and NF-KappaB binding in ten individuals. RNA-seq study with no treatment.
Variation in transcription factor binding among humans.
No sample metadata fields
View SamplesWe examined genome-wide variation in transcription factor binding in different individuals and a chimpanzee using chromatin immunoprecipitation followed by massively-parallel sequencing (ChIP-Seq). The binding sites of RNA Polymerase II (Pol II) as well as a key regulator of immune responses, NFkB, were mapped in ten HapMap lymphoblastoid cell lines derived from individuals of African, European, and Asian ancestry, including a parent-offspring trio. We also mapped gene expression in all ten human cell lines for two treatment conditions: a) no treatment and b) following induction by TNF-alpha. Overall design: Genome-wide comparison of Pol II and NF-KappaB binding in ten individuals. RNA-seq study with TNF-alpha treatment.
Variation in transcription factor binding among humans.
No sample metadata fields
View SamplesWe used microarray to detect pathway differences in the various brain regions in a monogenic in mucopolysaccharidosis type VII ( MPS VII ), a mouse model of a lysosomal storage disease
Dysregulation of gene expression in a lysosomal storage disease varies between brain regions implicating unexpected mechanisms of neuropathology.
Specimen part
View SamplesWe used microarray to detect pathway differences in the hippocampus in mucopolysaccharidosis type VII ( MPS VII ), a mouse model of a lysosomal storage disease
Integrated analysis of proteome and transcriptome changes in the mucopolysaccharidosis type VII mouse hippocampus.
Sex, Age, Specimen part
View SamplesThe goal of this study was to investigate the transcriptional regulation in cells grown on Fibronectin when compared to Collagen I
Loss of fibronectin from the aged stem cell niche affects the regenerative capacity of skeletal muscle in mice.
Sex, Age, Specimen part
View Samples