Unknown,Transcriptomics,Genomics,Proteomics

Dataset Information

Epigenetic Reprogramming Modulates Malignant Properties of Human Liver Cancer Cells

ABSTRACT: Reversal of DNA hypermethylation and associated gene silencing is an emerging cancer therapy approach. In this context we have addressed the impact of epigenetic alterations and local microenvironment on the functional and transcriptional reprogramming of hepatic cancer stem cells. (CSCs) using the DNMT1 inhibitor Zebularine (ZEB). We show for the first time that cellular context is a critical determinant in the response to DNMT1 inhibition resulting in either a long term epigenetically driven malignant reprogramming or an effective antitumor therapeutic reprogramming. Furthermore, permanent reduction of DNMT1 protein level renders the HCC cell lines insensitive to both DNMT1 inhibition and cellular context. These results emphasize the importance of decoding the mechanisms involved in therapeutic application of DNA demethylating agents. Huh7 and PLC treated with ZEB, and Huh7 depleted for DNMT1

ORGANISM(S): Homo sapiens

SUBMITTER: Snorri Thorgeirsson

PROVIDER: E-GEOD-47932 | biostudies-arrayexpress |

REPOSITORIES: biostudies-arrayexpress

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Epigenetic reprogramming modulates malignant properties of human liver cancer.

Raggi Chiara C Factor Valentina M VM Seo Daekwan D Holczbauer Agnes A Gillen Matthew C MC Marquardt Jens U JU Andersen Jesper B JB Durkin Marian M Thorgeirsson Snorri S SS

Hepatology (Baltimore, Md.) 20140501 6

<h4>Unlabelled</h4>Reversal of DNA hypermethylation and associated gene silencing is an emerging cancer therapy approach. Here we addressed the impact of epigenetic alterations and cellular context on functional and transcriptional reprogramming of hepatocellular carcinoma (HCC) cells. Our strategy employed a 3-day treatment of established and primary human HCC-derived cell lines grown as a monolayer at various cell densities with the DNMT1 inhibitor zebularine (ZEB) followed by a 3D culture to ...[more]

PMID: 24449497

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Project description:Background: HGF/c-Met signaling plays a pivotal role in hepatocyte survival and tissue remodeling during liver regeneration. Treatment with HGF has been shown to accelerate resolution of fibrotic liver lesions in experimental animal models. To formally address the importance of c-Met signaling in hepatocytes in the context of chronic liver injury, we have used hepatocyte-specific Metfl/fl;Alb-Cre+/- conditional knockout mice (KO) and a model of liver fibrosis. Methods: CCl4 was administrated biweekly over a period of 4 weeks (injury phase), and the animals were followed over the next 4 weeks (healing phase). Macroscopic and microscopic changes during the injury and healing phases were monitored by IHC. Deposition of ECM was assessed by Sirius red staining and hydroxiproline content. Activation of hepatic stellate cells (HSC) was estimated by a-SMA using WB and IHC. Expression levels of the selected key fibrotic molecules were evaluated by RT-qPCR and WB. Time-dependent global transcriptomic changes from whole livers and isolated hepatocytes were examined using gene expression microarrays. Results: Loss of HGF/c-Met signaling in hepatocytes altered the hepatic microenvironment and dramatically aggravated hepatic fibrogenesis. Increased liver damage was associated with decreased hepatocyte proliferation, progressive accumulation of HSCs, and delayed fibrinolysis causing increased collagen deposit. Dystrophic calcification of necrotic areas impaired phagocytosis, resulting in sustained inflammatory and fibrogenic signaling further augmenting severity of fibrogenesis. Global gene-expression analysis demonstrated upregulation of key fibrogenic molecules, such as Tgf-Ã¢ and Pdgf-Ã¢, paralleled by a decreased expression of genes important for cell cycle, stress response and regeneration, which could be attributed to the c-Met deficiency in hepatocytes. Additionally, key chemotactic and inflammatory cytokines, including Ccl2, SDF1/Cxcr4 and Spp1, were upregulated in Metfl/fl;Alb-Cre+/- hepatocytes. However, the major pro-fibrotic signaling originated from the non-parenchymal cell compartments, as revealed by cell type-specific gene expression signatures. Conclusion: These results indicate that lack of c-Met signaling in hepatocytes disrupts the balance between extracellular matrix production and degradation and establish a protective role for c-Met against adverse microenvironment leading to the development of fibrotic liver disease. In the present study, we reported a detailed and comprehensive dynamic characterization of the cellular and molecular alterations involved in fibrosis in the liver of c-Met transgenic mice. Liver samples from female animals were collected at various time-points after fibrosis induction using CCL4 ranging from 0 weeks to 3 weeks. Tissue samples were divided into two parts; one was fixed in 10% formalin for histological evaluation and the other was used for RNA analysis.

Project description:Recent studies suggested that embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) may represent different pluripotent states as defined by gene expression profiles and differentiation potential. Here we addressed a contribution of a lineage stage-specific donor cell memory in modulating the functional properties of iPSCs. iPSCs were generated from hepatic lineage cells at an early (hepatoblast-derived, HB-iPSCs) and end stage (adult hepatocyte, AH-iPSCs) of hepatocyte differentiation as well as from mouse fetal fibroblasts (MEF-iPSCs) using a lentiviral vector encoding four pluripotency-inducing factors Oct4, Sox2, Klf4, and c-Myc. All resulting iPS cell lines acquired iPSCs phenotype as judged by the accepted criteria including morphology, expression of pluripotency markers, silencing of transducing factors, capacity of multilineage differentiation in teratoma assay and normal diploid karyotype. However, hepatoblasts were more susceptible to reprogramming than either AH or MEF, and HB-iPSCs were more efficient in directed differentiation towards hepatocytic lineage as compared to AH-iPSCs, MEF-iPSCs or mESCs. Extensive comparative transcriptome analyses of the early passage iPSCs, donor cells and mESCs revealed that despite global similarities in gene expression patterns between generated iPSCs and mESCs, HB-iPSCs retained a transcriptional memory (7 up- and 20 down-regulated genes) typical of the original cells. Continuous passaging of HB-iPSCs abolished most of these differences including a superior capacity of hepatic re-differentiation. These results suggest that retention of lineage stage-specific donor memory in iPSCs may facilitate differentiation into donor cell type. The identified gene set may be helpful to improve hepatic differentiation for therapeutic application in liver disease modeling. A total of 200 ng RNA from four independent biological replicates of MACS-sorted mESC and iPSC were linearly amplified according to manufactures’ specification (Ambion, Austin, Tx,). For in vitro transcription (IVT), reactions were incubated for 16 h at 37ºC. The efficiency of the single round amplification was measured by NanoDrop (ND1000, Thermo Scientific). Hybridization, washing, detection (Cy3-streptavidin, Amersham Biosciences, GE Healthcare), and scanning were performed on an illumina iScan system (Illumina) using reagents and following protocols supplied by the manufacturer. The biotinylated cRNA (750 ng/sample) was hybridized on Sentrix beadchips human Ref-8v3 for 18 h at 58ºC while rocking (5 rpm).

Dataset Information

Epigenetic Reprogramming Modulates Malignant Properties of Human Liver Cancer Cells

Publications

Epigenetic reprogramming modulates malignant properties of human liver cancer.

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