DNA methyltransferase inhibitor zebularine inhibits human hepatic carcinoma cells proliferation and induces apoptosis.
ABSTRACT: Hepatocellular carcinoma is one of the most common cancers in world wide. During tumorigenesis, tumor suppressor and cancer-related genes are commonly silenced by aberrant DNA methylation in their promoter regions. Zebularine [1-(β-ᴅ-ribofuranosyl)-1,2-dihydropyrimidin-2-one] acts as an inhibitor of DNA methylation and exhibits chemical stability and minimal cytotoxicity both in vitro and in vivo. In this study, we explore the effect and possible mechanism of action of zebularine on hepatocellular carcinoma cell line HepG2. Here, we demonstrated that zebularine exhibited antitumor activity on HepG2 cells by inhibiting cell proliferation and inducing apoptosis. Zebularine treatment down-regulated CDK2 and phosphorylation of retinoblastoma protein (RB), and up-regulated p21WAF/CIP1 and p53. We also found that zebularine treatment up-regulated phosphorylation of p44/42 MAPK. These results suggest that p44/42 MAPK pathway play a role in zebularine induced cell cycle arrest by regulating activity of p21WAF/CIP1 and Rb. Furthermore, we found that zebularine induced apoptosis. Although proapoptotic protein Bax levels were not affected, antiapoptotic protein Bcl-2 level was down-regulated with zebularine treatment. The data in the present study suggest that the action of the double-stranded RNA-dependent protein kinase (PKR) is involved in inducing apoptosis with zebularine. These results provide a novel mechanism of zebularine-induced cell growth arrest and apoptosis in hepatocellular carcinoma. Three each independent batches of zebuluarine-treated and control HepG2 cells were subjected to illumina Human methylation 450K Beadchip analysis.
Project description:Investigation of whole genome gene expression level changes in hepatocellular carcinoma cell line hepG2 in regular culture, hepG2-slug in regular culture and hepG2-slug on Matrigel. Whole genome gene expression level changes have been compared in hepatocellular carcinoma cell line hepG2 in regular culture, hepG2-slug in regular culture and hepG2-slug on Matrigel. Roche NimbleGen micro-array analysis was employed to assess global genome expression in HepG2 in regular culture, HepG2-slug in regular culture and HepG2-slug on Matrigel. The results demonstrated that the up-regulated genes and the down-regulated genes increased significantly when HepG2-slug cells with VM forming ablity were cultured on Matrigel and formed VM.
Project description:Viscum coloratum (Kom.) Nakai is a variety of biological activities of medicinal plants, and the active component such as polysaccharides or alkaloids, also proved to have the effect of anti-tumor, anti-virus, anti-radiation, anti-oxidation and anti-infection. In this study, we examined the inhibition of three polysaccharide fractions from Viscum coloratum (Kom.) Nakai on HepG2 cells growth in a dose-dependent manner using CCK-8 kit assay, and flow cytometry analysis showed that VCP2 delayed cell cycle in G1 phase and induced apoptosis in HepG2 cells which may due to overexpressed p21Wafl/Cip1 and Cyclin D and decreased expressions of Cyclin E and CDK4, and the upregulated Bad, Smac and Caspase-3 and the downregulated Bcl-XL and XIAP may be one of reasons for inducing apoptosis in VCP2-treated HepG2 cells, but these effects may be not obviously related to Bad. Using iTRAQ and 2D-LC-MSMS, 113 differentially expressed proteins identified in normal and VCP2-treated HepG2 cells. Among them, the expressions of 59 proteins were upregulation, and the expressions of 54 proteins were downregulation. GO, pathways and PPI of differentially expressed proteins further analyzed in polysaccharides-treated HepG2 cells by bioinformatic approach. These findings widen our understanding the anti-tumor mechanisms of mistletoe polysaccharide and provide new clues for screening potent responsive protein to polysaccharides.
Project description:APRIL (TNFSF13) is a ligand of the TNF superfamily which binds to two receptors, BCMA and TACI. We have found that APRIL and its receptor BCMA are specifically enhanced in hepatocellular carcinoma, as compared to non-cancerous liver tissue. We further identified that HepG2 cells present the same ligand/receptor pattern as human hepatocellular carcinomas. We investigated the role of APRIL in HepG2 gene expression in a time course study. 24 hour serum starved HepG2 cells were treated with 200ng/ml of APRIL and RNA was collected at 0, 2, 6, and 12h. The collected RNA was used for hybridization on commercially available Affymetrix Human Genome U133 Plus 2.0 Arrays
Project description:Analysis of DDX20 knockdown - hepatocellular carcinoma cells. The expression levels of genes driven by NF-kB and related with carcinogenesis, were significantly enhanced in DDX20-knockdown cells. One condition experiment, HepG2 vs. HepG2-DDX20 knockdown cells
Project description:This experiment series addresses the role of coactivator SRC-1/NcoA-1 for the induction of interleukin-6 (IL-6) target genes in HepG2 cells. For that purpose, HepG2 human hepatocellular carcinoma cells were manipulated to stably express an shRNA that knocks down SRC-1 expression yielding the HepG2-∆Src1 cells. Either unmanipulated HepG2 or HepG2-∆Src1 cells were then treated for various periods with IL-6. Experiment Overall Design: HepG2 or HepG2-∆Src1 (with silenced SRC-1/NcoA-1 expression) cells were either left untreated or treated with 10 ng/ml IL-6 for 1 or 4 hours. Every experiment was carried out in replicate.
Project description:Hepatocellular carcinoma (HCC) is a frequent cancer with poor prognosis and with limited possibilities for anti-cancer treatment. Evidence has recently accumulated suggesting that multiple signaling pathways are activated in human cancer. It has been recently shown by exosome sequencing of HCC that 161 putative driver genes are associated with 11 recurrently altered pathways, suggesting that we need to inhibit these multiple pathways for HCC therapy. THOC5, a member of transcription/export (TREX) complex, that plays a role in less than 1% of mRNA processing in normal cells such as fibroblasts or macrophages, is not required for maintenance of mature hepatocytes. In this study, we have examined the role of THOC5 in human HCC. Enhanced THOC5 expression was not observed in differentiation grading 1 (G1) human HCC, but 78% of G2 and G3 exhibited increased levels of THOC5. Furthermore, the 50% depletion of THOC5 in hepatocellular carcinoma cell lines, Huh7 and HepG2 causes lipid accumulation and apoptosis. Transcriptome analysis using THOC5 depleted Huh7 and HepG2 cells revealed that 1049 and 837 genes were downregulated upon depletion of THOC5 in Huh7 and HepG2 cells, respectively. Among these genes, 396 were commonly downregulated in both cell lines. Some of these, such as tissue inhibitor of metalloproteinase 3 (TIMP3), tripartite motif containing 24 (TRIM24), ribosomal protein S6 kinase polypeptide 3 (RPS6KA3) and transmembrane emp24-like trafficking protein 10 (TMED10) are known to be fine tuners for several signal transduction pathways. The expression of these proteins was correlated with the THOC5 expression level in HCC. To inhibit multiple signaling pathways we are currently examining the effects of a combination of siRNAs against THOC5 target genes in HCC cell lines. Our data suggest that THOC5, which controls a set of genes that are involved in HCC malignancy can be a potential biomarker for HCC. In addition, THOC5 target gene, TMED10 may also be a novel biomarker of HCC. Furthermore, the suppression of the THOC5 gene per se or multiple THOC5 target genes may represent a novel strategy for cancer therapy. Huh7 and HepG2 cells were infected with lentiviral THOC5 and control shRNAs. Five days after infection, total RNAs were isolated and subjected to microarray analysis.
Project description:Single cell genome, DNA methylome, and transcriptome sequencing has been achieved separately. However, to analyze the regulation of RNA expression by genetic and epigenetic factors within an individual cell, it is necessary to analyze these omics simultaneously from the same single cell. Here we developed a single cell triple omics sequencing technique- scTrio-seq, to analyze the genome, DNA methylome, and transcriptome concurrently of a mammalian cell. 6 single human HepG2 cell line cells were sequenced using the newly developed scTrio-seq, other 2 HepG2 cells were sequenced using scRNA-seq and other 2 HepG2 cells were sequenced using scRRBS as technique control. 6 single mouse embryonic stem cells (mESCs) were sequenced using the newly developted scTrio-seq. Meanwhile, two scRNA-seq and two scRRBS were also completed using two mESCs separately. 26 single cells from hepatocellular carcinoma were sequenced using scTrio-seq to analyze the regulation relations between three omics of cancer cells.
Project description:Molecular targeted therapy has shown promise as a treatment for advanced hepatocellular carcinoma (HCC). Sorafenib, a multikinase inhibitor, recently received FDA approval for the treatment of advanced HCC. However, although sorafenib is well tolerated, concern for its safety has been expressed. Celecoxib (Celebrex®) is a selective cyclooxygenase-2 (COX-2) inhibitor wich exhibits antitumor effects in human HCC cells. The present study examined the interaction between celecoxib and sorafenib in two human liver tumor cell lines HepG2 and Huh7. Our data showed that each inhibitor reduced cell growth and the combination of celecoxib with sorafenib synergistically inhibited cell growth and increased apoptosis. To better understand the molecular mechanisms underlying the synergistic antitumor activity of combination, we investigated the expression profile of the combination-treated liver cancer cell lines, using microarray analysis. Combination treatment significantly altered expression levels of 1,986 and 2,483 transcripts in HepG2 and Huh7 cells, respectively. Genes, functionally involved in cell death, signal transduction and regulation of transcription were predominantly up-regulated, while genes implicated in metabolism, cell cycle control and DNA replication and repair were mainly down-regulated upon treatment. However, combination-treated HCC cell line displayed specificity in the expression and activity of crucial factors involved in hepatocarcinogenesis. The altered expression of some of these genes was confirmed by semiquantitative and quantitative RT-PCR and by Western blotting. Many novel genes emerged from our transcriptomics analyses, and further functional analyses may determine whether these genes can serve as potential molecular targets for more effective anti-HCC strategies. To identify new potential mechanisms of combined action of celecoxib and sorafenib, their effects on global gene expression in both cell lines were investigated and compared using the DNA microarray technology. Agilent 44K Human Whole Genome Oligonucleotide Microarrays (containing ~44,000 genes) were used to identify global gene expression changes in the HepG2 and Huh7 hepatocellular carcinoma (HCC) cell lines, following simultaneous treatment with 50 µM celecoxib and 7.5 µM sorafenib for 48 hours. All microarray experiments (a total of four) were performed in duplicates applying dye-swaps to avoid labeling bias.
Project description:Cholangiocarcinoma (CCA) is a cancer arising from the neoplastic transformation of cholangiocytes. During tumorigenesis, tumor suppressor and cancer-related genes are commonly silenced by aberrant DNA methylation in their promoter regions. Zebularine (1-(β-D-ribofuranosyl)-1,2-dihydropyrimidin-2-one) acts as an inhibitor of DNA methylation and exhibits chemical stability and minimal cytotoxicity both in vitro and in vivo. In this study, we explore the effect and possible mechanism of action of zebularine on CCA cells. We demonstrate that zebularine exerts an antitumor effect on CCA cells. Zebularine treatment decreased the concentrations of DNA methyltransferase (DNMT) proteins, and DNMT1 knockdown led to apoptotic cell death in the CCA cell lines TFK-1 and HuCCT1. DNA methylation analysis demonstrated that zebularine induced DNA demethylation, and the GO Biological Process terms “hemophilic cell adhesion”, “regulation of transcription, DNAdependent” and “Wnt signaling pathway” were found to be significantly enriched in association with demethylated genes. Furthermore, we observed that zebularine treatment decreased β-catenin protein levels in TFK-1 and HuCCT1 cells. These results suggest that zebularine alters DNA methylation status, and that some aspect of DNA demethylation by zebularine induces suppression of the Wnt signaling pathway, which leads to apoptotic cell death in CCA. We previously reported a novel mechanism of zebularine-induced cell growth arrest and apoptosis in hepatocellular carcinoma via a DNA methylation-independent pathway. Together, our present and previous studies indicate that zebularine could function as both a DNMT inhibitor and a non-DNMT inhibitor reagent, and that, while the optimal usage of zebularine may depend on cancer type, zebularine may be useful for chemotherapy against cancer. Overall design: DNA methylation profiles of cholangiocarcinoma-derived cell lines, TFK1 and HuCCT1, treated with or without zebularine were obtained in triplicate using Infinium HumanMethylation450 BeadChips (Illumina).
Project description:Increased α-fetoprotein (AFP) levels have been reported to predict a poor prognosis in hepatocellular carcinoma (HCC). We assessed the mechanism of AFP involvement in the progression of HCC and determined whether AFP could be a molecular target. We used human HCC cell lines to assess proliferation and apoptosis response to exogenous AFP. We introduced AFP small interfering RNA (siRNA) into HCC cell lines to examine whether it could inhibit cell proliferation and anti-apoptotic properties. The effects of systemically introduced AFP siRNA were assessed using a tumor xenotransplantation model. The effects of AFP on gene expression in HCC cell lines and human HCC specimens were examined. Exogenous AFP induced cell proliferation dose-dependently and inhibited apoptosis induced by 5-fluorouracil (5-FU) in all cell lines examined. AFP siRNA inhibited the proliferation of AFP-producing HCC cell lines and induced apoptosis in co-cultures with 5-FU. Tumor sizes in mice treated with AFP siRNA were significantly smaller than those in controls. AFP siRNA administration in mice induced a low proliferation index and a high apoptosis index in tumors. cDNA microarray analysis, reverse transcription-polymerase chain reaction (RT-PCR), and Western blot using HepG2 and HLE cells with AFP showed that AFP reduced expression of genes related to apoptosis (DFFB) and tumor suppression (NDRG2). Expression of these molecules was also suppressed in human HCC tissues that overexpress AFP. AFP is not only a passive tumor marker, but also an active tumor stimulator through several mechanisms. AFP siRNA introduction may be of possible therapeutic use for HCC. Keywords: Genetic modification Two-condition experiment, Control vs. AFP-stimulated cells.