The p53 protein is a cell-autonomous tumor suppressor that restricts malignant transformation by triggering cell cycle exit or apoptosis. p53 also promotes cellular senescence, a program that triggers a stable cell cycle arrest and can modify the tissue microenvironment through its effect on cell membrane and secretory proteins. Here we show that specific ablation of p53 in hepatic stellate cells, which undergo a process of proliferation and senescence in the fibrogenic response to liver damage, enhances liver cirrhosis, reduces survival and increases the malignant transformation of adjacent epithelial cells into hepatocellular carcinoma. This p53-dependent senescence program involves the release of secreted proteins which skew macrophages into a tumor-inhibiting M1-state that can eliminate senescent stellate cells. In contrast, p53-deficient stellate cells secrete factors that promote M2 polarization, which is pro-tumorigenic. Our study reveals that p53 can exert a non-cell-autonomous tumor suppressor response and suggests that this occurs, in part, by its ability to influence macrophage polarization.
Non-cell-autonomous tumor suppression by p53.
Specimen part, Treatment
View SamplesCellular senescence is a homeostatic program associated with tumor suppression, wound healing, and certain age related pathologies. Senescent cells display a repressive chromatin configuration thought to stably silence proliferation-promoting genes, while at the same time activate an unusual form of immune surveillance involving a secretory program referred to as the senescence-associated secretory phenotype (SASP). Here we demonstrate that senescence also involves a global remodeling of the enhancer landscape with recruitment of the chromatin reader BRD4 to newly activated super-enhancers adjacent to key SASP genes. Transcriptional profiling and functional studies indicate that BRD4 is required for the SASP and downstream paracrine signaling. Consequently, BRD4 inhibition disrupts immune cell-mediated targeting and elimination of premalignant senescent cells in vitro and in vivo. Our results identify a critical role for BRD4-bound super-enhancers in senescence immune surveillance and in the proper execution of a tumor-suppressive program. Overall design: Analysis of RNA isolated from human fibroblasts (IMR90) in proliferating, quiescent or senescent (HrasV12) conditions upon knockdown of Brd4, p65, p53, p53/RB, p16/21 or Vehicle and JQ1 treatment
BRD4 Connects Enhancer Remodeling to Senescence Immune Surveillance.
No sample metadata fields
View SamplesGene fusions arising from chromosomal translocations are key oncogenic drivers in soft tissue sarcomas but little is known about how they exert their oncogenic effects. Our study explores the molecular mechanisms by which the SS18-SSX fusion oncoprotein subverts epigenetic mechanisms of gene regulation to drive synovial sarcoma. Using functional genomics, we identify KDM2B – a histone demethylase and core component of a non-canonical Polycomb Repressive Complex 1 (PRC1.1) – as selectively required for sustaining synovial sarcoma cell transformation. SS18-SSX physically interacts with PRC1.1 and co-associates with SWI/SNF and KDM2B complexes on unmethylated CpG islands genome-wide. Via KDM2B, SS18-SSX binds and aberrantly activates expression of a series of developmentally regulated transcription factors that would otherwise be targets of polycomb-mediated repression, which is restored upon KDM2B depletion leading to irreversible mesenchymal differentiation. Thus, SS18-SSX de-regulates developmental programs to drive transformation by hijacking a transcriptional repressive complex to aberrantly activate gene expression. Overall design: RNA-Seq of human synovial sarcoma cells (HS-SY-II) in control cells (Ren.173) and upon knockdown of SS18-SSX1 (SS18.273 and SSX.1274) or of KDM2B (KDM2B. 4395 and KDM2B.4835) in duplicates.
The SS18-SSX Oncoprotein Hijacks KDM2B-PRC1.1 to Drive Synovial Sarcoma.
Subject
View SamplesCell polarity is crucial for the maintenance of epithelial cell function and its loss may have an im-portant role in the development and progression of cancer. We here show that overexpression and cytoplasmic enrichment of the baso-lateral polarity complex protein Scribble (Scrib) correlates with poor prognosis of hepatocellular cancer (HCC) patients. Expression of the cytoplasmic ScribP305L in hepatocellular cells induces epithelial to mesenchymal transition (EMT) and supports HCC cell invasion in comparison to cells expressing membrane-localized ScribWT. ScribP305L induces AKT signalling through destabilization of the phosphatases phosphatase and tensin homolog (PTEN) and PH domain and leucine rich repeat protein phosphatase 1 (PHLPP1). Moreover, cytoplasmic ScribP305L stimulates the expression of secreted protein acidic and cysteine rich (SPARC) de-pending on the AP1 constituents ATF2 and JunB, which drives HCC cell invasiveness. In vivo, combined hydrodynamic delivery of ScribP305L but not ScribWT and c-MYC initiates tumour for-mation in hepatocytes and cytoplasmic Scrib correlates with AKT phosphorylation, and AP1 ex-pression in human HCC tissues. Together, overexpression and mislocalization of Scrib represents an early event involved in the initiation and progression of liver cancer.
Cytoplasmic localization of the cell polarity factor scribble supports liver tumor formation and tumor cell invasiveness.
Cell line
View SamplesMost lung adenocarcinoma deaths are related to metastases, indicating the necessity of detecting and inhibiting tumor cell dissemination. We have identified that overexpression of miRNAs located on 14q32 was associated with metastasis in lung adenocarcinoma patients. For functional analysis, we utilized CRISPR activation technology to increase levels of miRNAs clustered on 14q32 in a coordinated manner, and the results showed that 14q32 miRNA overexpression promoted tumor cell migratory and invasive properties. Whole transcriptome microarray analysis of the miRNA-overexpressing cells was performed to define the underlying molecular mechanisms.
Epigenetically Regulated Chromosome 14q32 miRNA Cluster Induces Metastasis and Predicts Poor Prognosis in Lung Adenocarcinoma Patients.
Specimen part, Cell line
View SamplessiRNA-mediated inhibition compared to untreated cells and cells transfected with nonsense siRNA.
Yes-associated protein up-regulates Jagged-1 and activates the Notch pathway in human hepatocellular carcinoma.
Cell line, Treatment
View SamplesAutophagy is a mechanism that regulates cellular metabolism and clearance of damaged macromolecules and organelles. Impaired degradation of modified macromolecules contributes to cellular dysfunction and is observed in aged tissue and senescent cells. We have inactivated Atg7, an essential autophagy gene, in murine keratinocytes and have found in an earlier study that this resulted in increased baseline oxidative stress and reduced capacity to degrade crosslinked proteins after oxidative ultraviolet stress. To investigate whether autophagy deficiency would promote cellular aging, we studied, how Atg7 deficient (KO) and Atg7 bearing cells (WT) would respond to stress induced by Paraquat (PQ), an oxidant drug commonly used to induce cellular senescence.
Autophagy deficient keratinocytes display increased DNA damage, senescence and aberrant lipid composition after oxidative stress in vitro and in vivo.
No sample metadata fields
View SamplesPurpose: The phosphoinositide 3-kinase (PI3K) pathway is fundamental for cell proliferation and survival and is frequently altered and activated in neoplasia, including carcinomas of the lung. In this study we investigated the potential of targeting the catalytic class IA PI3K isoforms in small cell lung cancer (SCLC), which is the most aggressive of all lung cancer types. Experimental Design: The expression of PI3K isoforms in patient specimens was analyzed. The effects on SCLC cell survival and downstream signaling were determined following PI3K isoform inhibition by selective inhibitors or down-regulation by small interfering RNA. Results: Over-expression of the PI3K isoforms p110 and p110 was shown by immunohistochemistry in primary SCLC tissue samples. Targeting the PI3K p110 with RNA interference (RNAi) or selective pharmacological inhibitors resulted in strongly affected cell proliferation of SCLC cells in vitro and in vivo, while targeting p110 was less effective. Inhibition of p110 also resulted in increased apoptosis and autophagy, which was accompanied by decreased phosphorylation of Akt and components of the mammalian target of rapamycin (mTOR) pathway, such as the ribosomal S6 protein, and the eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). A DNA microarray analysis revealed that p110 inhibition profoundly affected the balance of pro- and anti-apoptotic Bcl-2 family proteins. Finally, p110 inhibition led to impaired SCLC tumor formation and vascularization in vivo. Conclusion: Together our data demonstrate the key involvement of the PI3K isoform p110 in multiple tumor-promoting processes in SCLC.
Targeting the phosphoinositide 3-kinase p110-α isoform impairs cell proliferation, survival, and tumor growth in small cell lung cancer.
Cell line, Treatment
View SamplesExosomes, endosome-derived membrane microvesicles, contain a specific set of RNA transcripts that are involved in cell-cell communication and hold a great potential as disease biomarkers. To systemically characterize exosomal RNA profiles, we performed RNA sequencing analysis using three human plasma samples and evaluated efficacies of small RNA library preparation protocols from 3 manufacturers. Overall design: We tested the six samples (A1 and A2, B1 and B2, C1 and C2) using two small RNA library preparation kits: NEBNext Multiplex Small RNA library Prep Set from New England Biolab (NEB) and NEXTflex Small RNA Sequencing Kit from Bioo Scientific (BS). We also tested Illumina’s TrueSeq Small RNA Sample Preparation Kit (ILMN) in sample A1 and A2. Together, we tested these plasma samples by sequencing 14 indexed libraries. This study allowed direct comparison of current small RNA library preparation protocols and identified the most suitable strategy for future exosomal RNA sequencing analysis.
Characterization of human plasma-derived exosomal RNAs by deep sequencing.
Specimen part
View SamplesLong wavelength Ultraviolet (UVA-1) radiation causes oxidative stress that leads to the formation of noxious substances within the skin. As a defensive mechanism skin cells produce detoxifying enzymes and antioxidants when they detect modified molecules. We have recently shown that UVA-1 irradiation oxidizes the abundant membrane phospholipid 1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine (PAPC), which then induced the synthesis of the stress response protein heme oxygenase 1 (HO-1) in dermal fibroblasts. Here we examined the effects of UVA-1 and (UV-) oxidized phospholipids on the global gene expression in human dermal fibroblasts. We identified a cluster of genes that were co-induced by UVA-1-oxidized PAPC and UVA-1 radiation. The cluster included HO-1, glutamate-cysteine ligase modifier subunit (GCLM), aldo-keto reductases-1-C1 and -C2 (AKR1C1, AKR1C2), and interleukin 8 (IL8). These genes are members of the cellular stress response system termed antioxidant response or Phase II detoxification. Accordingly, the regulatory regions of all these genes contain binding sites for NF-E2-related factor 2 (Nrf2), a major regulator of the antioxidant response.
NF-E2-related factor 2 regulates the stress response to UVA-1-oxidized phospholipids in skin cells.
No sample metadata fields
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