Project description:Phosphoproteomic analysis of EGF stimulated MCF7 cells. This dataset is the basis for the development of modeling of signaling networks. A fundamental challenge in biology is to delineate the signaling pathways that govern cellular responses to genetic and environmental cues. Phosphoproteomics is an emerging technology that provides key data on activity levels of proteins under conditions of interest. However, the interpretation of these data is hampered by the lack of methods that can translate site-specific information into global maps of active proteins and signaling networks. To meet this challenge, we propose PHOTON, a method for integrating phosphorylation data with protein-protein interaction networks to identify active proteins and pathways and pinpoint functional phosphosites. We demonstrate the utility of PHOTON by applying it to interpret existing and novel phosphoproteomic datasets related to EGF and insulin responses. PHOTON substantially outperforms the widely-used cutoff approach, providing highly reproducible predictions that are more in line with current biological knowledge
Project description:ELK1 is a well-known target of the ERK branch (EGF-responsive) of the MAP kinase pathway. This transcription profiling experiment studied the effects of ELK1 depletion by siRNA and subsequent EGF stimulation.
Project description:OBJECTIVE: Sorafenib is effective in hepatocellular carcinoma (HCC), but patients ultimately present disease progression. Molecular mechanisms underlying acquired resistance are still unknown. Herein, we characterize the role of tumor-initiating cells (T-ICs) and signaling pathways involved in sorafenib resistance. DESIGN: HCC xenograft mice treated with sorafenib (n=22) were explored for responsiveness (n=5) and acquired resistance (n=17). Mechanism of acquired resistance were assessed by: 1) Role of T-ICs by in vitro sphere formation and in vivo tumorigenesis assays using NOD/SCID mice, 2) Activation of alternative signaling pathways and 3) Efficacy of anti-FGF and anti-IGF drugs in experimental models. Gene expression (microarray, qRT-PCR) and protein analyses (immunohistochemistry, western blot) were conducted. A novel gene signature of sorafenib resistance was generated and tested in 2 independent cohorts. RESULTS: Sorafenib-acquired resistance tumors showed significant enrichment of T-ICs (164 cells needed to create a tumor) vs. sorafenib-sensitive tumors (13400 cells) and non-treated tumors (1292 cells), p<0.001. Tumors with sorafenib-acquired resistance were enriched with IGF and FGF signaling cascades (FDR<0.05). In vitro, cells derived from sorafenib-acquired resistant tumors and two sorafenib-resistant HCC cell lines were responsive to IGF or FGF inhibition. In vivo, FGF blockade delayed tumor growth and improved survival in sorafenib-resistant tumors. A sorafenib-resistance 175-gene signature was characterized by enrichment of progenitor-cell features, aggressive tumoral traits and predicted poor survival in 2 cohorts (n=442 HCC patients). CONCLUSION: Acquired resistance to sorafenib is driven by tumor initiating cells with enrichment of progenitor markers and activation of IGF and FGF signaling. Inhibition of these pathways would benefit a subset of patients after sorafenib progression. Transcriptomic profile of subcutaneous Huh7 cells-derived tumors treated with sorafenib that developed acquired resistance to the drug (n=4), remain responsive to sorafenib (n=3) or were treated with brivanib after development of resistance (n=3). Gene profiling of hepatospheres generated from tumors with acquired resistance to sorafenib (n=3) and non-treated tumors (n=3) was also analyzed.
Project description:Viral infections of the CNS are of increasing concern, especially among immunocompromised populations. Rodent models are often inappropriate for studies of CNS infection, as many viruses, including JC Virus (JCV) and HIV, cannot replicate in rodent cells. Consequently, human fetal brain-derived multipotential CNS progenitor cells (NPCs) that can be differentiated into neurons, oligodendrocytes, or astrocytes, have served as a model for CNS studies. NPCs can be non-productively infected by JCV, while infection of progenitor-derived astrocytes (PDAs) is robust. We profiled cellular gene expression at multiple times during differentiation of NPCs to PDAs. Several activated transcription factors show commonality between cells of the brain in which JCV replicates and lymphocytes in which JCV is likely latent. Bioinformatic analysis determined transcription factors that may influence the favorable transcriptional environment for JCV in PDAs. This study attempts to provide a framework for understanding the functional transcriptional profile necessary for productive JCV infection. 19 Human samples: 4 Human Fetal Brain NPC 0h, 4 Human Fetal Brain NPC in Serum 1h, 4 Human Fetal Brain NPC in Serum 1d, 4 Human Fetal Brain NPC in Serum 7d, 3 Human Fetal Brain NPC in Serum 30d.
Project description:Combining genome-wide microarray and functional analyses, we found that EGFR activation abrogates barrier function, increasing transepidermal water loss (TEWL) and transepithelial permeability of water-soluble ions and higher molecular weight dextrans, in part by disrupting the expression of tight junction proteins. EGF decreases certain lipid matrix free fatty acids and ceramides by its actions to repress the expression of specific biosynthetic enzymes. Activation of EGFR inhibits cornified envelope formation by regulating the expression of 59 percent of the known contributing genes. EGF-responsiveness enriches more than 100 genes known to be associated with skin diseases. These data are used to obtain 2,676 density-dependent genes that are differentially expressed in response to EGF treatment. The 16 microarrays were preprocessed using the 5th percentile of region method in dChip. Genes with at least a 1.5 fold difference between the untrated samples at 50% and 100% confluent cell density were exported for further analysis. Two-way ANOVA was used to identify differentially expressed genes by either density or treatment factors using JMP Genomics 4.1 (SAS). Multiple hypothesis testing was corrected by Benjamini-Hochberg false discovery rate control at the 0.05 level. Pair-wise comparisons were performed using the TukeyM-bM-^@M-^Ys Honestly Significant Difference test.
Project description:Results of growing MCF10A cells continuously in serum free media supplemented with EGF (MCF10A) or AREG (MCF10A+AREG) followed by 24 hours of ligand withdrawl and measuring gene expression provides information as to what genes are regulated by AREG and EGF in a normal mammary epithelial cell model MCF10A cells continuously in serum free media supplemented with 10ng/ml of EGF (MCF10A) or 20ng/ml of AREG (MCF10A+AREG) followed by 24 hours of ligand withdrawl. Total RNA was collected and genome-wide analysis of expression was performed on RNA from each cell line.
Project description:We used microarrays to assess gene expression differences between proliferating adult NSCs/neural progenitors with and without active SIRT1. Adult NSCs/neural progenitors were isolated from 8 week old Sirt1lox/lox and NestinCre;Sirt1lox/lox mice (129SV strain), cultured for one passage in growth factors (EGF and bFGF) before isolation at early passage 2 for RNA extraction and hybridization on Affymetrix microarrays. Gene expression data were adjusted for background and normalized using RMA.
