The estrogen receptor-alpha (ER) determines breast cancer cell phenotype and is a prognostic indicator. A better understanding of the mechanisms controlling ER function may uncover improved strategies for the treatment of breast cancer. Proteasome inhibition was previously reported to regulate estrogen-induced transcription but the mechanisms by which it influences ER function remain controversial. In this study we investigated the transcriptome-wide effects of the proteasome inhibitor Velcade on estrogen-regulated transcription in MCF7 human breast cancer cells and demonstrate a specific global decrease in estrogen-induced transcription.
Estrogen-dependent gene transcription in human breast cancer cells relies upon proteasome-dependent monoubiquitination of histone H2B.
Cell line
View SamplesHere, we examined the role of intestinal epithelial specific tumor suppressive function of 53. We provide evidence that p53 plays a dual role during carcinogen-induced tumorigenesis. At the initiation stage, p53 controls DNA damage and survival of initiated epithelia. In contrast, at later stages, loss of p53 is associated with the formation of an inflammatory microenvironment that is linked to epithelial mesenchymal transition, invasion and metastasis and the activation of NF-kappaB and Stat3. Thus, we propose a novel p53 controlled tumor suppressive function during the progression stage of colorectal cancer that is independent of its well-established role in cell cycle regulation, apoptosis and senescence.
Loss of p53 in enterocytes generates an inflammatory microenvironment enabling invasion and lymph node metastasis of carcinogen-induced colorectal tumors.
Specimen part
View SamplesBCL6 inhibitor induces derepression of BCL6 target genes and shows a similar transcriptional program to BCL6 siRNA Overall design: Genome-wide profiling of mRNA transcript levels in human DLBCL cell line with BCL6 inhibitor and DMSO control.
Rationally designed BCL6 inhibitors target activated B cell diffuse large B cell lymphoma.
Specimen part, Subject
View SamplesRationale: The BCL6 oncogene is constitutively activated by chromosomal translocations and amplification in ABC-DLBCLs, a class of DLBCLs that respond poorly to current therapies. Yet the role of BCL6 in maintaining these lymphomas has not been investigated. BCL6 mediates its effects by recruiting corepressors to an extended groove motif. Development of effective BCL6 inhibitors requires compounds exceeding the binding affinity of these corepressors. Objectives: To design small molecule inhibitors with superior potency vs. endogenous BCL6 ligands for unmet putative therapeutic needs such as targeting ABC-DLBCL. Findings: We used an in silico drug design functional-group mapping approach called SILCS to create a specific BCL6 inhibitor with 10-fold greater potency than endogenous corepressors. The compound, called FX1, binds in such a way as to occupy an essential region of the BCL6 lateral groove. FX1 disrupts BCL6 repression complex formation, reactivates BCL6 target genes, and mimics the phenotype of mice engineered to express BCL6 with lateral groove mutations. This compound eradicated established DLBCLs xenografts at low doses. Most strikingly, FX1 suppressed ABC-DLBCL cells as well as primary human ABC-DLBCL specimens ex vivo. Conclusions: ABC-DLBCL is a BCL6 dependent disease that can be targeted by novel inhibitors able to exceed the binding affinity of natural BCL6 ligands. Overall design: gene expression profiles of DLBCL cases
Rationally designed BCL6 inhibitors target activated B cell diffuse large B cell lymphoma.
Specimen part, Subject
View SamplesActivation-induced cytidine deaminase (AID) is essential for the generation of antibody memory but also targets oncogenes among others. We investigated the transcriptional regulation of the AID gene, Aicda, in the class switchinducible CH12F3-2 cells, and found that the Aicda regulation involves derepression by several layers of positive regulatory elements in addition to the 5 promoter region. The 5 upstream region contains functional motifs for the response to signaling by cytokines, CD40-ligand, or stimuli that activate NF-B. The first intron contains functional binding elements for the ubiquitous silencers c-Myb and E2f and for B cellspecific activator Pax5 and E-box-binding proteins.
B cell-specific and stimulation-responsive enhancers derepress Aicda by overcoming the effects of silencers.
Specimen part
View SamplesBackground and aims. The etiopathology of inflammatory bowel diseases is still poorly understood. To date, only few little data are available on the microbiota composition in ulcerative colitis (UC), representing a major subform of inflammatory bowel diseases. Currently, one of the main challenges is to unravel the interactions between genetics and environmental factors in the onset or during the progression and maintenance of the disease. The aim of the present study was to analyse twin pairs discordant for UC for both gut microbiota dysbiosis and host expression profiles at a mucosal level and to get insight into the functional genomic crosstalk between microbiota and mucosal epithelium in vivo. Methods. Biopsies were sampled from the sigmoid colon of both healthy and diseased siblings from UC discordant twin pairs but also from healthy twins. Microbiota profiles were assessed by 16S rDNA libraries while mRNA expression profiles were analysed from the same volunteers using Affymetrix microarrays.
Twin study indicates loss of interaction between microbiota and mucosa of patients with ulcerative colitis.
Specimen part, Subject
View SamplesAnalysis of 2 cultured normal lung cell lines, Normal Human Bronchial Epithelial (NHBE) and Human Small Airway Epithelial (SAEC) cells (Lonza, Walkersville, MD), following treatment with 5-aza-dC to induce DNA demethylation. These results provide insight into the role of epigenetic alterations, specifically demethylation, in differential gene expression in various lung neoplasms.
Integrative discovery of epigenetically derepressed cancer testis antigens in NSCLC.
Specimen part, Cell line
View SamplesWhole genome expression profiling of 40 healthy human twins (20 monozygotic, 20 dizygotic)
Genetic control of global gene expression levels in the intestinal mucosa: a human twin study.
Sex, Age
View SamplesSilencing of tumor suppressor genes plays a vital role in head and neck carcinogenesis. Aberrant hypermethylation in the promoter region of some known or putative tumor suppressor genes (TSGs) occurs frequently during the development of various cancers including head and neck squamous cell carcinoma (HNSCC). In this study we used an expanded mRNA expression profiling approach followed by microarray expression analysis to identify epigenetically inactivated genes in HNSCC. Two HNSCC cell lines were treated with 5-aza-2-deoxycytidine followed by microarray analysis to identify epigenetically silenced genes in HNSCC. 1960, 614, and 427 genes were upregulated in HNSCC cell lines JHU-012, JHU-011 and the combination of both cell lines, respectively. HNSCC tumor and normal mucosal samples were used for gene profiling by a 47K mRNA gene expression array and we found, 7140 genes were downregulated in HNSCC tumors compared to normal mucosa as determined by microarray analysis and were integrated with cell line data. Integrative analysis defined 126 candidate genes, of which only seven genes showed differentially methylation in tumors and no methylation in normal mucosa after bisulfite sequencing. After validation by QMSP, one gene, GNG7, was confirmed as being highly methylated in tumors and unmethylated in normal mucosal and salivary rinse samples demonstrating cancer-specific methylation in HNSCC tissues. TXNIP and TUSC2 were partially methylated in tumors and normal salivary rinses but unmethylated in normal mucosa. We concluded GNG7 as a highly specific promoter methylated gene associated with HNSCC. In addition, TXNIP and TUSC2 are also potential biomarkers for HNSCC.
Identification of guanine nucleotide-binding protein γ-7 as an epigenetically silenced gene in head and neck cancer by gene expression profiling.
Sex
View SamplesUsing an siRNA screen we identify a role for GPR65 in the defense against intracellular pathogens. Epithelial cells and macrophages lacking GPR65 exhibited impaired clearance of intracellular bacteria as well as an accumulation of aberrant phagosomes and lysosomes. Transcriptional profiling revealed changes in genes associated with lysosomal function. Overall design: Bone marrow-derived macrophages from WT or Gpr65-/- mice were harvested for RNA analysis.
Genetic Coding Variant in GPR65 Alters Lysosomal pH and Links Lysosomal Dysfunction with Colitis Risk.
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