The cellular response to genotoxic stress is mediated by a well-characterized network of DNA surveillance pathways. The contribution of posttranscriptional gene regulatory networks to the DNA damage response (DDR) has not been extensively studied. Here, we systematically identified RNA-binding proteins differentially interacting with polyadenylated transcripts upon exposure of human breast carcinoma cells to ionizing irradiation (IR). Interestingly, more than 260 proteins including many nucleolar proteins showed increased binding to poly(A) RNA in IR-exposed cells. The functional analysis of DDX54, a candidate genotoxic stress responsive RNA helicase, revealed that this protein is an immediate-to-early DDR regulator required for the splicing efficacy of its target IR-induced pre-mRNAs. Upon IR exposure, DDX54 acts by increased interaction with a well defined class of pre-mRNAs which harbor introns with weak acceptor splice sites, as well as by protein-protein contacts within components of U2 snRNP and spliceosomal B complex, resulting in lower intron retention and higher processing rates of its target transcripts. Since DDX54 promotes survival after exposure to IR its expression and/or mutation rate may impact DDR-related pathologies. Our work indicates the relevance of many uncharacterized RBPs potentially involved in the DDR. Overall design: Gene expression profiling of MCF-7 cells upon DDX54 knockdown exposed to ionizing radiation
DDX54 regulates transcriptome dynamics during DNA damage response.
Specimen part, Cell line, Subject, Time
View SamplesRCC cells (786-O) were transfected with VHL. The parental cell line should be compared to the transfectant (+VHL) under nomoxia as well as under hypoxia conditions.
Distinct von Hippel-Lindau gene and hypoxia-regulated alterations in gene and protein expression patterns of renal cell carcinoma and their effects on metabolism.
Cell line
View SamplesWe cultured tumor cells from 22 GBM under medium conditions favoring the growth of neural stem cells. 11 out of 15 primary GBM contained a significant CD133+ subpopulation that comprised cells showing all hallmarks of neural stem cells. Cell lines derived from these CD133+ GBM showed a neurosphere-like, non-adherent growth pattern. In contrast, 4 out of 15 cell lines derived from primary GBM grew adherent in vitro and were driven by CD133- tumor cells that fulfilled stem cell criteria. In vivo, these GBM were characterized by a significantly lower proliferation index but similar GFAP staining as compared to CD133+ GBM. Gene arrays from 2x3 representative cells lines are given.
CD133(+) and CD133(-) glioblastoma-derived cancer stem cells show differential growth characteristics and molecular profiles.
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View SamplesAll living cells rely on the communication with other cells to ensure their function and survival. Molecular signals are sent among cells of the same cell type and from cells of one cell type to another. In cancer, not only the cancer cells themselves are responsible for the malignancy, but also stromal (non-cancerous) cells and the molecular signals they send to cancer cells are important factors that determine the severity and outcome of the disease. Therefore, the identification of stromal signals and their influence on cancer cells is important when looking for novel treatment strategies.
Causal Modeling of Cancer-Stromal Communication Identifies PAPPA as a Novel Stroma-Secreted Factor Activating NFκB Signaling in Hepatocellular Carcinoma.
Specimen part
View SamplesCancer cells alter their metabolism to support their malignant properties. By transcriptomic analysis we identified the glucose-transforming polyol pathway (PP) gene aldo-keto-reductase-1-member-B1 (AKR1B1) as strongly correlated with epithelial-to-mesenchymal transition (EMT). This association was confirmed staining samples from lung cancer patients and from an EMT-driven colon cancer mouse model with p53 deletion. In vitro, mesenchymal-like cancer cells showed increased AKR1B1 levels and AKR1B1 knockdown was sufficient to revert EMT. An equivalent level of EMT suppression was measured by targeting the downstream enzyme sorbitol-dehydrogenase (SORD), further pointing at the involvement of the PP. Comparative RNA sequencing profiling confirmed a profound alteration of EMT in PP-deficient cells, revealing a strong repression of TGF-Beta signature genes. Mechanistically, excess glucose was found to promote EMT through autocrine TGF-Beta stimulation, while PP-deficient cells were refractory to glucose-induced EMT. PP represents a molecular link between glucose metabolism and cancer differentiation and aggressiveness, and a novel potential therapeutic target. Overall design: 3x3 biological replicated samples; 2 groups of samples with shRNA-mediated specific gene inhibition and scrambled control cells
Polyol Pathway Links Glucose Metabolism to the Aggressiveness of Cancer Cells.
Cell line, Treatment, Subject
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