Gene expression profiles of peripheral blood samples from C57BL/6 mice exposed with ionizing radiation.
Biological pathway selection through Bayesian integrative modeling.
Sex, Specimen part, Treatment, Time
View SamplesTemporal expression profiling was utilized to define transcriptional regulatory pathways in vivo in a mouse muscle regeneration model. Potential downstream targets of MyoD were identified by temporal expression, promoter data base mining, and gel shift assays; Slug and calpain 6 were identified as novel MyoD targets. Slug, a member of the snail/slug family of zinc finger transcriptional repressors critical for mesoderm/ectoderm development, was further shown to be a downstream target by using promoter/reporter constructs and demonstration of defective muscle regeneration in Slug null mice.
Slug is a novel downstream target of MyoD. Temporal profiling in muscle regeneration.
No sample metadata fields
View SamplesEKLF is a Krppel-like transcription factor identified as a transcriptional activator and chromatin modifier in erythroid cells. EKLF-deficient (Eklf -/-) mice die at day 14.5 of gestation from severe anemia. In this study, we demonstrate that early progenitor cells fail to undergo terminal erythroid differention in Eklf -/- embryos. To discover potential EKLF target genes responsible for the failure of erythropoiesis, transcriptional profiling was performed with RNA from wild type and Eklf -/- early erythroid progenitor cells. These analyses identified significant perturbation of a network of genes involved in cell cycle regulation, with the critical regulator of the cell cycle, E2f2, at a hub. E2f2 mRNA and protein levels were markedly decreased in Eklf -/- early erythroid progenitor cells, which showed a delay in the G1-to-S-phase transition. Chromatin immunoprecipitation analysis demonstrated EKLF occupancy at the proximal E2f2 promoter in vivo. Consistent with the role of EKLF as a chromatin modifier, EKLF binding-sites in the E2f2 promoter were located in a region of EKLF-dependent DNase I sensitivity in early erythroid progenitor cells. We propose a model in which EKLF-dependent activation and modification of the E2f2 locus is required for cell cycle progression preceding terminal erythroid differentiation.
Failure of terminal erythroid differentiation in EKLF-deficient mice is associated with cell cycle perturbation and reduced expression of E2F2.
Age, Specimen part
View SamplesSummary: Astrocytomas can be categorized as either low grade or high grade (glioblastoma). Low grade astrocytomas are not generally aggressive tumors whereas glioblastomas are and in turn have a high mortality rate. The purpose of this experiment is to identify genetic differences between the two types.
Overexpression of the EGFR/FKBP12/HIF-2alpha pathway identified in childhood astrocytomas by angiogenesis gene profiling.
No sample metadata fields
View SamplesPurpose: Gene expression signatures developed to measure the activity of oncogenic signaling pathways have been used to dissect the heterogeneity of tumor samples and to predict sensitivity to various cancer drugs that target components of the relevant pathways, thus potentially identifying therapeutic options for subgroups of patients. To facilitate broad use, including in a clinical setting, the ability to generate data from formalin-fixed, paraffin-embedded (FFPE) tissues is essential. Experimental Design: Patterns of pathway activity in matched fresh-frozen and FFPE xenograft tumor samples were generated using the MessageAmp Premier methodology in combination with assays using Affymetrix arrays. Results generated were compared with those obtained from fresh-frozen samples using a standard Affymetrix assay. In addition, gene expression data from patient matched fresh-frozen and FFPE melanomas were also utilized to evaluate the consistency of predictions of oncogenic signaling pathway status. Results: Significant correlation of pathway activity predictions was observed between paired fresh-frozen and FFPE xenograft tumor samples. In addition, significant concordance of pathway activity predictions was also observed between patient matched fresh-frozen and FFPE melanomas. Conclusion: Reliable and consistent predictions of oncogenic pathway activities can be obtained from FFPE tumor tissue samples. The ability to reliably utilize FFPE patient tumor tissue samples for genomic analyses will lead to a better understanding of the biology of disease progression and, in the clinical setting, will provide tools to guide the choice of therapeutics to those most likely to be effective in treating a patients disease.
A methodology for utilization of predictive genomic signatures in FFPE samples.
Specimen part
View SamplesGenome-wide expression profiling was performed on 50 core needle biopsies from 18 breast cancer patients using Affymetrix GeneChip Human Genome Plus 2.0 Arrays.
Intratumor heterogeneity and precision of microarray-based predictors of breast cancer biology and clinical outcome.
Disease, Disease stage, Subject
View SamplesAbstract from paper - Potti A, et al
A genomic strategy to refine prognosis in early-stage non-small-cell lung cancer.
No sample metadata fields
View SamplesWe investigated the clinical implications of lung developmental transcription factors (TTF-1, NKX2-8, and PAX9) which we recently discovered as cooperating oncogenes activated by way of gene amplification at chromosome 14q13 in lung cancer. Using stable transfectants of human bronchial epithelial cells, RNA expression profiles (signatures) representing activation of the biological pathways defined by each of the three genes were determined and used to risk stratify a non-small cell lung cancer (NSCLC) clinical dataset consisting of ninety-one early stage tumors. Co-activation of the TTF-1 and NKX2-8 pathways identified a cluster of patients with poor survival, representing approximately 20% of patients with early stage NSCLC, whereas activation of individual pathways did not reveal significant prognostic power. Importantly, the poor prognosis associated with co-activation of TTF-1 and NKX2-8 was validated in two other independent clinical datasets. Further, lung cancer cell lines showing co-activation of the TTF-1 and NKX2-8 pathways were shown to exhibit resistance to cisplatin, the standard of care for the treatment of NSCLC. Since TTF-1 and NKX2-8 lack specific inhibitors at the current time, we explored an alternative therapeutic strategy. Using signatures of signaling pathway activation, we identified deregulation of specific oncogenic pathways (Ras and Myc) in the TTF-1/NKX2-8 co-activated cohort.
Characterizing the developmental pathways TTF-1, NKX2-8, and PAX9 in lung cancer.
No sample metadata fields
View SamplesGene expression signatures have the capacity to identify clinically significant features of breast cancer and can predict which individual patients are likely to be resistant to neoadjuvant therapy, thus providing the opportunity to guide treatment decisions.
Gene expression profiles of multiple breast cancer phenotypes and response to neoadjuvant chemotherapy.
Specimen part
View SamplesSignatures of Oncogenic Pathway Deregulation in Human Cancers.
Oncogenic pathway signatures in human cancers as a guide to targeted therapies.
No sample metadata fields
View Samples