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.
Tumour initiating cells and IGF/FGF signalling contribute to sorafenib resistance in hepatocellular carcinoma.
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View SamplesHere we present a strategy to adapt hESCs to high-throughput screening (HTS) conditions, resulting in an assay suitable for the discovery of small molecules that drive hESC self-renewal or differentiation. Use of this new assay has led to the identification of several currently marketed drugs and natural compounds promoting short-term hESC maintenance and compounds directing early lineage choice. Global gene expression analysis upon drug treatment reveals overlapping and novel pathways correlated to hESC self-renewal and differentiation. Our results demonstrate feasibility of hESC-based HTS and enhance the available repertoire of chemical compounds for manipulating hESC fate.
High-throughput screening assay for the identification of compounds regulating self-renewal and differentiation in human embryonic stem cells.
No sample metadata fields
View SamplesTranscription factor induced reprogramming of one specialized cell type into another is a promising approach for regenerative medicine. However, the process still remains poorly understood, in large part because of the lack of adequate experimental models. Here we describe a robust cell reprogramming system consisting of a B cell line with an inducible form of C/EBPa that can be converted into macrophages with essentially 100% efficiency in only 2 to 3 days. The conversion involves reciprocal changes in cell surface antigen expression, increase in cell granularity and size, alterations in cellular structures, formation of membrane extensions, acquisition of phagocytic capacity and an increased inflammatory responsiveness as well as migratory activity. Analysis of the transcriptome shows complex reciprocal regulation of B cell and macrophage genes, including transcription factors required for the formation of the two lineages. The fact that the cells become irreversibly committed to a macrophage fate within 1 to 2 days after activation of C/EBPa show that they are truly reprogrammed. The system should be useful to study epigenetic and cell biological mechanisms of transcription factor induced cell reprogramming.
A robust and highly efficient immune cell reprogramming system.
Cell line
View SamplesLittle is known about the immune performance and interactions of CNS microglia/macrophages in glioma patients. Microglia/macrophages were found to be the predominant immune cell infiltrating gliomas (approximately 1% of total cells); others identified are myeloid dendritic cells (DCs), plasmacytoid DCs, and T cells. Using a procedure enriching for CD11b/c+CD45+ glioma-infiltrating microglia/macrophages (GIMs) from postoperative tissue specimens of glioma patients (Hussain et al. Neuro Oncol. 2006 J;8(3):261-79) gene expression profiles were obtained form paired samples. The expression profiles are used to identify expression signatures contributed by GIMs in glioblastoma data sets (Murat et al, submitted).
Modulation of angiogenic and inflammatory response in glioblastoma by hypoxia.
Sex, Specimen part
View SamplesRegulation of homeostasis and development of cardiac muscle tissues is controlled by a core set of transcription factors. The MEF2 family plays a critical role in these processes.
Antagonistic regulation of cell-cycle and differentiation gene programs in neonatal cardiomyocytes by homologous MEF2 transcription factors.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
AF10 regulates progressive H3K79 methylation and HOX gene expression in diverse AML subtypes.
Specimen part, Disease
View SamplesGene expression data from VHL teratomas comparing genes differentially expressed based on apoptotic response to tumor microenvironment.
Pleiotropic effects of the trichloroethylene-associated P81S VHL mutation on metabolism, apoptosis, and ATM-mediated DNA damage response.
Specimen part
View SamplesIn human cells, Staufen1 is double-stranded RNA-binding protein involved in several cellular functions including mRNA localization, translation and decay. We used a genome wide approach to identify and compare the mRNA targets of mammalian Staufen1. The mRNA content of Staufen1 mRNPs was identified by probing DNA microarrays with probes derived from mRNAs isolated from immunopurified Staufen-containing complexes following transfection of HEK293T cells with a Stau1-HA expressor. Our results indicate that 7% of the cellular RNAs expressed in HEK293T cells are found in Stau1-containing mRNPs. There is a predominance of mRNAs involved in cell metabolism, transport, transcription, regulation of cell processes and catalytic activity.
A genome-wide approach identifies distinct but overlapping subsets of cellular mRNAs associated with Staufen1- and Staufen2-containing ribonucleoprotein complexes.
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View SamplesIn human cells, Staufen2 is a double-stranded RNA-binding protein involved in several cellular functions. Although 51% identical to Staufen1, these proteins are nevertheless found in different RNA particles. In addition, differential splicing events generate Staufen2 isoforms that only differ at their N-terminal extremities. We used a genome wide approach to identify and compare the mRNA targets of mammalian Staufen2 isoforms. The mRNA content of Staufen mRNPs was identified by probing DNA microarrays with probes derived from mRNAs isolated from immunopurified Staufen2-containing complexes following transfection of HEK293T cells with Stau2-HA (59kDa) or Stau2-HA (62kDa) expressors. Our results indicate that 11% of the cellular RNAs expressed in HEK293T cells are found in Stau2-containing mRNPs. There is a predominance of mRNAs involved in cell metabolism, transport, transcription, regulation of cell processes and catalytic activity.
A genome-wide approach identifies distinct but overlapping subsets of cellular mRNAs associated with Staufen1- and Staufen2-containing ribonucleoprotein complexes.
No sample metadata fields
View SamplesTo better understand the scale of gene expression changes that occur during the formation of mature adipocytes from preadipocytes, we compared and characterised the transcriptome profile of mesenchymal stromal cells derived from human adipose tissue, otherwise known as adipose-derived stromal cells (ASCs), undergoing adipocyte differentiation on day 1, 7, 14 and 21 (representing the early to late stage process of adipogenesis). Microarray technique was systematically employed to study gene expression in adipose-derived stromal cells during adipogenic differentiation over a 21 day period to identify genes that are important in driving adipogenesis in humans.
Genome-wide analysis of gene expression during adipogenesis in human adipose-derived stromal cells reveals novel patterns of gene expression during adipocyte differentiation.
Sex, Age, Specimen part, Subject
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