Project description:Specific regulation of target genes by transforming growth factor-β (TGF-β) in a given cellular context is determined in part by transcription factors and cofactors that interact with the Smad complex. In the present study, we determined Smad2 and Smad3 (Smad2/3) binding regions in the promoters of known genes in HepG2 hepatoblastoma cells, and compared them to those in HaCaT epidermal keratinocytes to elucidate the mechanisms of cell type- and context-dependent regulation of transcription induced by TGF-β. Our results show that 81% of the Smad2/3 binding regions in HepG2 cells were not shared with those found in HaCaT cells. Hepatocyte nuclear factor 4α (HNF4α) is expressed in HepG2 cells, but not in HaCaT cells, and the HNF4α binding motif was identified as an enriched motif in the HepG2-specific Smad2/3 binding regions. ChIP-sequencing analysis of HNF4A binding regions under TGF-β stimulation revealed that 32.5% of the Smad2/3 binding regions overlapped HNF4A bindings. MIXL1 was identified as a new combinatorial target of HNF4A and Smad2/3, and both the HNF4A protein and its binding motif were required for the induction of MIXL1 by TGF-β in HepG2 cells. These findings generalize the importance of binding of HNF4A on Smad2/3 binding genomic regions for HepG2-specific regulation of transcription by TGF-β, and suggest that certain transcription factors expressed in a cell-type-specific manner play important roles in the transcription regulated by the TGF-β-Smad signaling pathway. HepG2 cells were treated with TGF-beta for 1.5 h or left untreated. anti-HNF4A ChIP-seq was performed. One lane was used for each sample.
Project description:Specific regulation of target genes by transforming growth factor-β (TGF-β) in a given cellular context is determined in part by transcription factors and cofactors that interact with the Smad complex. In the present study, we determined Smad2 and Smad3 (Smad2/3) binding regions in the promoters of known genes in HepG2 hepatoblastoma cells, and compared them to those in HaCaT epidermal keratinocytes to elucidate the mechanisms of cell type- and context-dependent regulation of transcription induced by TGF-β. Our results show that 81% of the Smad2/3 binding regions in HepG2 cells were not shared with those found in HaCaT cells. Hepatocyte nuclear factor 4α (HNF4α) is expressed in HepG2 cells, but not in HaCaT cells, and the HNF4α binding motif was identified as an enriched motif in the HepG2-specific Smad2/3 binding regions. ChIP-sequencing analysis of HNF4A binding regions under TGF-β stimulation revealed that 32.5% of the Smad2/3 binding regions overlapped HNF4A bindings. MIXL1 was identified as a new combinatorial target of HNF4A and Smad2/3, and both the HNF4A protein and its binding motif were required for the induction of MIXL1 by TGF-β in HepG2 cells. These findings generalize the importance of binding of HNF4A on Smad2/3 binding genomic regions for HepG2-specific regulation of transcription by TGF-β, and suggest that certain transcription factors expressed in a cell-type-specific manner play important roles in the transcription regulated by the TGF-β-Smad signaling pathway.
Project description:Specific regulation of target genes by transforming growth factor-β (TGF-β) in a given cellular context is determined in part by transcription factors and cofactors that interact with the Smad complex. In the present study, we determined Smad2 and Smad3 (Smad2/3) binding regions in the promoters of known genes in HepG2 hepatoblastoma cells, and compared them to those in HaCaT epidermal keratinocytes to elucidate the mechanisms of cell-type- and context-dependent regulation of transcription induced by TGF-β. Our results show that 81% of the Smad2/3 binding regions in HepG2 cells were not shared with those found in HaCaT cells. Hepatocyte nuclear factor 4α (HNF4α) is expressed in HepG2 cells, but not in HaCaT cells, and the HNF4α binding motif was identified as an enriched motif in the HepG2-specific Smad2/3 binding regions. ChIP-sequencing analysis of HNF4α binding regions under TGFα stimulation revealed that 32.5% of the Smad2/3 binding regions overlapped HNF4α bindings. MIXL1 was identified as a new combinatorial target of HNF4α and Smad2/3, and both the HNF4α protein and its binding motif were required for the induction of MIXL1 by TGF-β in HepG2 cells. These findings generalize the importance of binding of HNF4α on Smad2/3 binding genomic regions for HepG2-specific regulation of transcription by TGF-β, and suggest that certain transcription factors expressed in a cell-type-specific manner play important roles in the transcription regulated by the TGF-β-Smad signaling pathway.
Project description:To elucidate the gene profile of anti-fibroproliferative effects of cyclosporine, we added TGF-b and/or CsA to MRC5 (fetal human lung fibroblast) cell line. After 24 hours serum starvation, fibroblasts were treated with 3 ng/ml TGF-β1 and were treated with or without 2μg/ml Cyclosporine and effects were examined at 48 hours after treatment. Expression of three genes (IGFBP3, ID1 and PPARG) from this signature was quantified in the same RNA samples by real-time PCR. TGF-β and cyclosporine induced gene expression data was measured in MRC5 (fetal human fibroblast cell line) at 48h after treatments. The dose of TGF-β was 3 ng/ml and cyclosporine was 2 μg/ml. The comparison was done between four groups (control, TGF-β, cyclosporine and TGF-β plus cyclosporine).Three independent experiments were performed at each treatments using different samples for each experiment.
Project description:Smad2/3 are transcription factors that engage in TGF-beta-induced transcription. We determined and analyzed HepG2 and Hep3B-specific Smad2/3 binding sites by ChIP-chip. We used expression microarrays to compare the Smad2/3 and HNF4alpha binding sites identified by ChIP-chip or ChIP-seq, respectively, to TGF-beta-induced gene expressions. HepG2 cells were transfected with control or HNF4A siRNAs and treated with 3 ng/ml TGF-beta for 0, 1.5 and 24 h (6 samples in total, no replicates). Total RNA was extracted and expression microarray analysis was performed as described in the protocols.
Project description:TGF-beta treatment of Panc-1 pancreatic adenocarcinoma cell line on Affymetrix HG_U133_plus_2 arrays; triplicate experiments. The goal of the experiment is to profile temporal gene expression changes during TGF-beta-induced epithelial-mesenchymal transition (EMT). During EMT cancer cells lose their epithelial specifc proteins and gain mesenchymal proteins to acquire migratory and invasive phenotype essential for metastasis. Human Panc-1 pancreatic adenocarcinoma cell line was treated with 5 ng/mL TGF-beta for 48 h to induce EMT. The experiment was repeated 3 times. Samples were assayed using Affymetrix HG_U133_plus_2 arrays with 54675 probe-sets, using standard techniques. Human Panc-1 pancreatic adenocarcinoma cell line was treated with 5 ng/mL TGF-beta for 48 h. The experiment was repeated 3 times. Samples were assayed using Affymetrix HG_U133_plus_2 arrays with 54675 probe-sets, using standard techniques.
Project description:Advanced ovarian cancer is the most lethal gynecologic malignancy in the United States. Ovarian cancer cells are known to have diminished response to TGF-beta, but it remains unclear whether TGF-beta can modulate ovarian cancer cell growth in an indirect manner through cancer-associated fibroblasts (CAFs). Using transcriptome profiling analyses on TGF-beta-treated ovarian fibroblasts, we identified a TGF-beta-responsive gene signature in ovarian fibroblasts. Identifying TGF-beta-regulated genes in the ovarian microenvironment helps in understanding the role of TGF-beta in ovarian cancer progression. The human telomerase-immortalized ovarian fibroblast line NOF151 was treated with 5ng/mL of either TGF-beta-1 or TGF-beta-2. Total RNA was isolated from control samples and TGF-beta-treated fibroblasts samples at 48 hours post-treatment, followed by cDNA synthesis, IVT and biotin labeling. Samples were then hybridized onto Affymetrix Human Genome U133 Plus 2.0 microarrays. For each treatment group, three independent samples were prepared for the microarray experiment.