Oxidative stress appears to be implicated in the pathogenesis of various diseases including alcoholic liver injury. In this study we investigated the mechanism of apoptosis induced by tert-butyl hydroperoxide (TBHP) in HepG2 human hepatoblastoma cells. Treatment with TBHP significantly reduced glutathione content and glutathione reductase activity, and increased glutathione peroxidase activity, indicating that TBHP induced oxidative stress in the HepG2 cells. TBHP also induced reduction of cell viability and DNA fragmentation, a hallmark of apoptosis, in a dose-dependent manner. In addition, TBHP induced a sustained increase in intracellular Ca2+ concentration, which was completely prevented by the extracellular Ca2+ chelation with EGTA. TBHP also induced Mn2+ influx. These results indicate that the intracellular Ca2+ increase by TBHP is exclusively due to Ca2+ influx from the extracellular site. Treatment with either an extracellular (EGTA) or an intracellular Ca2+ chelator (BAPTA/AM) significantly suppressed the TBHP-induced apoptosis. Taken together, these results suggest that TBHP induced the apoptotic cell death in the HepG2 cells and that Ca2+ influx may play an important role in the apoptosis induced by TBHP.
Apoptosis/drug effects* ; Calcium Signaling/drug effects* ; Chelating Agents/pharmacology ; Egtazic Acid/pharmacology ; Egtazic Acid/analogs & derivatives ; Hepatoblastoma/pathology* ; Hepatoblastoma/metabolism ; Hepatoblastoma/drug therapy ; Human ; Manganese/metabolism ; Oxidative Stress/drug effects ; Tumor Cells, Cultured ; tert-Butylhydroperoxide/pharmacology*

Apoptosis ; drug effects ; Hep G2 Cells ; Hepatoblastoma ; metabolism ; Humans ; Oligonucleotides, Antisense ; pharmacology ; Proto-Oncogene Proteins c-mdm2 ; genetics

OBJECTIVETo explore the expression and diagnostic significance of glypican-3 (GPC3) in hepatoblastoma.

METHODSFive tissue microarray paraffin blocks were constructed to include 54 cases of hepatoblastoma. The tumor tissue samples were obtained from 3 surgical biopsies, 33 needle biopsies, 5 stage I resection tumors, and 13 stage II resection tumors after transcatheter arterial chemoembolization. Ten samples of non-neoplastic hepatic tissue adjacent to tumor were used as control. Immunohistochemical staining of GPC3 (clone 1G12) was performed. Among the 54 cases of hepatoblastoma, 22 cases were fetal subtype, 24 cases were mixed fetal and embryonal subtype and 8 cases were mixed epithelial and mesenchymal type.

RESULTSGPC3 was positive in fetal epithelial cells (54/54, 100%), but negative or weakly positive in embryonic epithelial cells in all cases of hepatoblastoma. Undifferentiated small cells and all mesenchymal components were negative for the expression. Non-neoplastic hepatocytes adjacent to tumor were negative for GPC3 expression (0/10) .

CONCLUSIONSFetal epithelial components of hepatoblastoma express GPC3 protein detectable by immunohistochemistry. Normal hepatocytes after birth, small cell undifferentiated and embryonic epithelial components of hepatoblastoma do not or weakly express GPC3 protein. Therefore, GPC3 immunohistochemistry offers a valuable aid to the diagnosis of hepatoblastoma in infants and children.

Child ; Child, Preschool ; Diagnosis, Differential ; Epithelial Cells ; metabolism ; Female ; Glypicans ; metabolism ; Hepatoblastoma ; diagnosis ; metabolism ; pathology ; Humans ; Immunohistochemistry ; Infant ; Infant, Newborn ; Liver Neoplasms ; diagnosis ; metabolism ; pathology ; Male

OBJECTIVETelomerase, a complex of ribose and nucleoprotein, is a specific marker of tumor, which expresses in 98% infinite cell lines and 90% malignant tumor organizations and whose function is to maintain the length of telomere. Human telomerase reverse-transcript protein subunit (hTERT) is the key element and rate-limiting factor of telomerase activity. Our study was to investigate the effects of antisense hTERT gene on biological characteristics of hepatoblastoma cell line in vitro.

METHODSThe sense and antisense hTERT eukaryotic expression vectors that we had constructed before were transfected into hepatoblastoma cell line HepG2 by using the SuperFect transfection reagent (Qiagen) according to the manufacturer's instructions, then the HepG2-s and HepG2-as of G418-resistant colonies were obtained with G418 and identified for the presence of hTERT insert by PCR with T7 and pcDNA3.1/BGH reverse primers. After that, we have detected the endogenous hTERT mRNA expression and telomerase activity by quantitative real-time RT-PCR and TRAP-silver staining assay in cells from each group. Meanwhile, MTT cellular proliferation assay, soft agar colony formation assay and flow cytometry were employed to analyze if the proliferation capacity of liver cancer cells was affected in vitro and the tumor cells could be induced to apoptosis by antisense hTERT.

RESULTSAntisense hTERT significantly down-regulated the endogenous hTERT mRNA expression (15.35 +/- 1.72/HepG2-as, 43.8 +/- 2.89/HepG2-s, 45.2 +/- 3.46/HepG2) (n = 10, t = 7.61, P < 0.01) and telomerase activity in HepG2, compared to blank control and sense hTERT. After 20 passages of three group cells, a 7-day cell growth curve and the numbers (size) of soft agar colony formation showed the proliferation and the anchorage-independent growth in HepG2-as were significantly suppressed (50.6 +/- 4.8/HepG2-as, 113.52 +/- 8.15/HepG2-s, 119.12 +/- 10.82/HepG2) (n = 10, t = 4.54, P < 0.01 and n = 10, t = 3.96, P < 0.01), compared to HepG2 and HepG2-s. However there was a significant increase in apoptosis percentage of HepG2-as by flow cytometry (n = 10, t = 9.24, P < 0.01 and n = 10, t = 8.37, P < 0.01), compared to control group.

CONCLUSIONSAntisense hTERT could significantly suppress the hepatoblastoma cell growth and reverse its malignant phenotypes in vitro and cause the increase in apoptosis percentage of HepG2, thus it might be applied in malignant tumor gene therapy through the telomerase-targeted molecular mechanism.

Cell Division ; genetics ; Cell Line, Tumor ; DNA-Binding Proteins ; Hepatoblastoma ; genetics ; pathology ; Humans ; RNA, Antisense ; genetics ; RNA, Messenger ; genetics ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; Telomerase ; genetics

BACKGROUNDSodium valproate inhibits proliferation in neuroblastoma and glioma cells, and inhibits proliferation and induces apoptosis in hepatoblastoma cells. Information describing the molecular pathways of the antitumor effects of sodium valproate is limited; therefore, we explored the mechanisms of action of sodium valproate in the human hepatoblastoma cell line, HepG2.

METHODSThe effects of sodium valproate on the proliferation of HepG2 cells were evaluated by the Walsh-schema transform and colony formation assays. Sodium valproate-induced apoptosis in HepG2 cells was investigated with fluorescence microscopy to detect morphological changes; by flow cytometry to calculate DNA ploidy and apoptotic cell percentages; with Western blotting analyses to determine c-Jun N-terminal kinases (JNK), p-JNK, Bcl-2, Bax, and caspase-3 and -9 protein expression levels; and using JC-1 fluorescence microscopy to detect the membrane potential of mitochondria. Statistical analyses were performed using one-way analysis of variance by SPSS 13.0 software.

RESULTSOur results indicated that sodium valproate treatment inhibited the proliferation of HepG2 cells in a dose-dependent manner. Sodium valproate induced apoptosis in HepG2 cells as it: caused morphologic changes associated with apoptosis, including condensed and fragmented chromatin; increased the percentage of hypodiploid cells in a dose-dependent manner; increased the percentage of annexin V-positive/propidium iodide-negative cells from 9.52% to 74.87%; decreased JNK and increased phosphate-JNK protein expression levels; reduced the membrane potential of mitochondria; decreased the ratio of Bcl-2/Bax; and activated caspases-3 and -9.

CONCLUSIONSodium valproate inhibited the proliferation of HepG2 cells, triggered mitochondria-dependent HepG2 cell apoptosis and activated JNK.

Apoptosis ; drug effects ; Blotting, Western ; Cell Proliferation ; drug effects ; Flow Cytometry ; Hep G2 Cells ; Hepatoblastoma ; metabolism ; Humans ; JNK Mitogen-Activated Protein Kinases ; metabolism ; Membrane Potential, Mitochondrial ; drug effects ; Microscopy, Fluorescence ; Mitochondria ; metabolism ; Valproic Acid ; pharmacology

OBJECTIVETo study the mechanism of hepatitis C virus (HCV) gene regulation and the inhibitory effect of antisense RNA on HCV gene expression in vitro.

METHODSThe hepatoblastoma cell line (HepG2) was co-transfected by recombinant plasmid of antisense RNA complementary to HCV 5' untranslated region (5'UTR)and HCV 5' UTR Directed luciferase (luc) gene expression recombinant plasmid. Meanwhile a reversed HCV 5'UTR recombinant plasmid which can not transcribe as antisense RNA in the cell and a recombinant plasmid in which the luc was regulated by simian virus 40 (sv40) 5'UTR were used as controls respectively. The level of luc gene expression was determined by an enzymatic assay.

RESULTSThe antisense RNA which directed to HCV 5'UTRcould obviously knock down the level of luc gene expression and the close-dependent inhibition of antisense RNA was observed at the same time. However the above inhibition was not shown in the cells co-transfected by reversed HCV 5'UTR recombinant plasmid and HCV 5'UTR directed luc gene expression recombinant plasmid. No reduction was observed in luc gene expression level in the cell co-transfected by both antisense RNA recombinant plasmid and SV40 5'UTR directed luc gene expression recombinant plasmid.

CONCLUSIONHCV 5'UTR plays an important role in regulation of viral gene expression. The antisense RNA complementary to HCV 5'UTR could effectively inhibit the gene expression regulated by HCV 5'UTR in vitro.

5' Untranslated Regions ; genetics ; Cell Line, Tumor ; Gene Expression Regulation, Viral ; Genes, Viral ; Hepacivirus ; genetics ; Hepatoblastoma ; pathology ; Humans ; Liver Neoplasms ; pathology ; Luciferases ; genetics ; metabolism ; Plasmids ; RNA, Antisense ; pharmacology ; RNA, Viral ; genetics ; Recombinant Proteins ; genetics ; Transfection

OBJECTIVETo study the effects of Qushi Huayu Decoction (QHD) contained serum on fatty deposition and tumor necrosis factor alpha (TNF-alpha) secretion of hepatic lipotoxicity model in vitro, for further investigating the mechanism of the decoction for preventing and treating fatty liver.

METHODSThe steatosis with TNF-alpha secretion lipotoxic model of HepG2 induced by long-chain free fatty acid (FFA) was duplicated. Groups of normal, model cells and model cells treated with different concentrations of QHD contained serum were set up to test the content of TNF-alpha in culture supernate and triglyceride (TG) in cells, as well as to observe the ultrastructural change of cells by oil-red staining and the protein expression and gene expression of cellular TNF-alpha.

RESULTSAfter being stimulated with FFA for 24 h, marked deposition of lipid with high content of TG presented in the cells of model group. Compared with the normal group, not only TNF-alpha content of culture supernate but also the protein expression and mRNA expression of intracellular TNF-alpha increased significantly. Contrast to the model group, the contents of TG in cells and TNF-alpha in supernate as well as the protein and mRNA expression of TNF-alpha in the model cell group treated with 10% QHD were lower significantly (all P < 0.01).

CONCLUSIONQHD could significantly inhibit the fatty deposition and TNF-alpha secretion in HepG2 cells induced by free fatty acid.

Animals ; Blotting, Western ; Cell Line, Tumor ; Drugs, Chinese Herbal ; pharmacology ; Fatty Acids ; pharmacology ; Hepatoblastoma ; genetics ; metabolism ; pathology ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; Microscopy, Electron, Transmission ; RNA, Messenger ; biosynthesis ; genetics ; Rats ; Rats, Sprague-Dawley ; Reverse Transcriptase Polymerase Chain Reaction ; Serum ; Triglycerides ; metabolism ; Tumor Necrosis Factor-alpha ; genetics ; metabolism

OBJECTIVETo study the expressions and activities of Rho GTPases in hypoxia and its relationship with tumor angiogenesis.

METHODSThree tumor cell lines were used in this study: gastric cancer cell lines AGS, SGC7901 and hepatocellular carcinoma cell line HepG2. Expression level of Rac1 mRNA was detected by semi-quantitative RT-PCR. Activity of Rac1 was determined by pull-down assay and expression of HIF-1alpha, VEGF, p53 and PTEN protein was detected by Westernblot.

RESULTSThe expression level of Rac1 mRNA was significantly increased in hypoxia compared to normoxia. Pull-down assay showed that hypoxia-induced activity of Rac1 was elevated in a time-dependent manner and climaxed at 3 hours. The expressions of HIF-1alpha and VEGF protein were up-regulated, while those of PTEN and p53 protein were down-regulated.

CONCLUSIONThese results indicate that hypoxia enhances Rac1 expression which might be involved in tumor angiogenesis by reacting with hypoxia-responsive genes.

Cell Hypoxia ; Cell Line, Tumor ; Hepatoblastoma ; blood supply ; metabolism ; pathology ; Humans ; Hypoxia-Inducible Factor 1, alpha Subunit ; biosynthesis ; genetics ; Liver Neoplasms ; blood supply ; metabolism ; pathology ; Neovascularization, Pathologic ; PTEN Phosphohydrolase ; biosynthesis ; genetics ; RNA, Messenger ; biosynthesis ; genetics ; Stomach Neoplasms ; blood supply ; metabolism ; pathology ; Tumor Suppressor Protein p53 ; biosynthesis ; genetics ; Vascular Endothelial Growth Factor A ; biosynthesis ; genetics ; rac1 GTP-Binding Protein ; biosynthesis ; genetics ; rho GTP-Binding Proteins ; biosynthesis ; genetics

Fucoidan is one of the main bioactive components of polysaccharides. The current study was focused on the anti-tumor effects of fucoidan on human heptoma cell line HepG2 and the possible mechanisms. Fucoidan treatment resulted in cell cycle arrest and apoptosis of HepG2 cells in a dose-dependent manner detected by MTT assay, flow cytometry and fluorescent microscopy. The results of flow cytometric analysis revealed that fucoidan induced G2/M arrest in the cell cycle progression. Hoechst 33258 and Annexin V/PI staining results showed that the apoptotic cell number was increased, which was associated with a dose-dependent up-regulation of Bax and down-regulation of Bcl-2 and p-Stat3. In parallel, the up-regulation of p53 and the increase in reactive oxygen species were also observed, which may play important roles in the inhibition of HepG2 growth by fucoidan. In the meantime, Cyclin B1 and CDK1 were down-regulated by fucoidan treatment. Down-regulation of p-Stat3 by fucoidan resulted in apoptosis and an increase in ROS in response to fucoidan exposure. We therefore concluded that fucoidan induces apoptosis through the down-regulation of p-Stat3. These results suggest that fucoidan may be used as a novel anti-cancer agent for hepatocarcinoma.
Antineoplastic Agents ; pharmacology ; Apoptosis ; drug effects ; Blotting, Western ; CDC2 Protein Kinase ; genetics ; metabolism ; Cyclin B1 ; genetics ; metabolism ; Dose-Response Relationship, Drug ; Down-Regulation ; drug effects ; Flow Cytometry ; G2 Phase Cell Cycle Checkpoints ; genetics ; Gene Expression Regulation, Neoplastic ; drug effects ; Hep G2 Cells ; Hepatoblastoma ; genetics ; metabolism ; pathology ; Humans ; Liver Neoplasms ; genetics ; metabolism ; pathology ; Microscopy, Fluorescence ; Polysaccharides ; pharmacology ; Proto-Oncogene Proteins c-bcl-2 ; genetics ; metabolism ; Reactive Oxygen Species ; metabolism ; Reverse Transcriptase Polymerase Chain Reaction ; STAT3 Transcription Factor ; genetics ; metabolism ; Tumor Suppressor Protein p53 ; genetics ; metabolism ; bcl-2-Associated X Protein ; genetics ; metabolism