• Parasites, Hosts and Diseases
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• v.61 no.4
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• pp.388-396
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• 2023

Entamoeba histolytica is an enteric tissue-invasive protozoan parasite causing amoebic colitis and liver abscesses in humans. Amoebic contact with host cells activates intracellular signaling pathways that lead to host cell death via generation of caspase-3, calpain, Ca²⁺ elevation, and reactive oxygen species (ROS). We previously reported that various NADPH oxidases (NOXs) are responsible for ROS-dependent death of various host cells induced by amoeba. In the present study, we investigated the specific NOX isoform involved in ROS-dependent death of hepatocytes induced by amoebas. Co-incubation of hepatoma HepG2 cells with live amoebic trophozoites resulted in remarkably increased DNA fragmentation compared to cells incubated with medium alone. HepG2 cells that adhered to amoebic trophozoites showed strong dichlorodihydrofluorescein diacetate (DCF-DA) fluorescence, suggesting intracellular ROS accumulation within host cells stimulated by amoebic trophozoites. Pretreatment of HepG2 cells with the general NOX inhibitor DPI or NOX2-specific inhibitor GSK 2795039 reduced Entamoeba-induced ROS generation. Similarly, Entamoeba-induced LDH release from HepG2 cells was effectively inhibited by pretreatment with DPI or GSK 2795039. In NOX2-silenced HepG2 cells, Entamoeba-induced LDH release was also significantly inhibited compared with controls. Taken together, the results support an important role of NOX2-derived ROS in hepatocyte death induced by E. histolytica.

• Biomolecules & Therapeutics
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• v.10 no.4
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• pp.287-292
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• 2002

To find new inhibitory effects from oriental drugs, Albizziae root was extracted in methanol and the extracted was stepwisely fractionated by hexane, chloroform, ethylacetate, butanol and water. In cytotoxic effect of Albizziae root fractions against cancer cell lines including human hepatoma cells(HepG2) were investigated. Expecially the butanol fraction exhibited a inhibition effects on the growth of human hepatoma cells(HepG2). It inhibited of HepG2 cells with the value of IC50. The activities of qutathione after B(a)P treatment were markedly decreased than control, but those levels were increased by the treatment of Albizziae root methanol fraction. The activity of glutathione-S-transferase after B(a)P treatment were markedly decreased than control, but those levels were increased by the treatment of Albizziae root methanol traction. Induction of phase II enzymes is a major mechanism of chemoprevention. The induction levels of quinone reductase(QR) activity in cultured murine hepatoma(Hepa IcIc7)cell by methanol extract of Albizziae root were measured. Among the tested tractions, the extracts of butanol were found to induce QR activities over 2.8 fold than control. These results suggest that Albizziae root has chemopreventive Potential by inducing QR activities and GST levels and increasing GSH

• Archives of Pharmacal Research
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• v.28 no.1
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• pp.73-80
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• 2005

The effect of capsaicin on apoptotic cell death was investigated in HepG2 human hepatoma cells. Capsaicin induced apoptosis in time- and dose-dependent manners. Capsaicin induced a rapid and sustained increase in intracellular $Ca^{2+}$ concentration, and BAPTA, an intracellular $Ca^{2+}$ chelator, significantly inhibited capsaicin-induced apoptosis. The capsaicin-induced increase in the intracellular $Ca^{2+}$ and apoptosis were not significantly affected by the extracellular $Ca^{2+}$ chelation with EGTA, whereas blockers of intracellular $Ca^{2+}$ release (dantrolene) and phospholipase C inhibitors, U-73122 and manoalide, profoundly reduced the capsaicin effects. Interestingly, treatment with the vanilloid receptor antagonist, capsazepine, did not inhibit either the increased capsaicin-induced $Ca^{2+}$ or apoptosis. Collectively, these results suggest that the capsaicin-induced apoptosis in the HepG2 cells may result from the activation of a PLC-dependent intracellular $Ca^{2+}$ release pathway, and it is further suggested that capsaicin may be valuable for the therapeutic intervention of human hepatomas.

• Journal of Nutrition and Health
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• v.37 no.3
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• pp.182-192
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• 2004

Conjugated linoleic acid (CLA) is the mixture of positional and geometric isomers of linoleic acid (LA), which is found abundantly in dairy products and meats. This study was performed to investigate the anticarcinogenic effect of CLA in HepG2 hepatoma cells. HepG2 cell were treated with LA and CLA at the various concentrations of 10, 20, 40, 80 uM each at different incubation times. After each incubation times, cell proliferation, fatty acids incorporation into cell, peroxidation and postaglandin E$_2$ (PGE$_2$) and thromboxane $A_2$ (TXA$_2$) for the eicosanoid metabolism were measured. LA treated HepG2 cells were increased cell growth 6 - 70％ of control whereas CLA increased cell death the half of those in LA group (p 〈 0.001). LA and CLA were incorporated very well into the cellular membranes four times higher than in control according to concentration and longer incubation times. Moreover, LA synthesized significantly arachidonic acids corresponding with LA concentration compared to CLA supplementation. The supplementation with LA increased intracellular lipid peroxides concentration corresponding with LA concentration and five times higher than those in CLA significantly at any incubation times (p 〈 0.001). PGE$_2$ and TXA$_2$ levels were three to twenty times lower in condition of CLA treatments than LA, respectively. Overall, the dietary CLA might change the HepG2 cell growth by the changes of cell composition, production of lipid peroxide. Since CLA have not changed the levels of arachidonic acid of cell membrane, which was sources of eicosanoids, eicosanoid synthesis was not increased in CLA compared to LA. Our results was suggest CLA has a possibility to protect the progress of atherosclerosis because CLA does not produce lipid production and endothelial contraction factors in liver.

• Archives of Pharmacal Research
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• v.27 no.12
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• pp.1245-1252
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• 2004

Although ascorbate (vitamin C) has been shown to have anti-cancer actions, its effect on human hepatoma cells has not yet been investigated, and thus, the exact mechanism of this action is not fully understood. In this study, the mechanism by which ascorbate induces apoptosis using HepG2 human hepatoblastoma cells is investigated. Ascorbate induced apoptotic cell death in a dose-dependent manner in the cells, was assessed through flow cytometric analysis. Contrary to expectation, ascorbate did not alter the cellular redox status, and treatment with antioxidants (N-acetyl cysteine and N,N-diphenyl-p-phenylenediamine) had no influence on the ascorbate-induced apoptosis. However, ascorbate induced a rapid and sustained increase in intracellular $Ca^{2+}$ concentration. EGTA, an extracellular $Ca^{2+}$ chelator did not significantly alter the ascorbate-induced intracellular $Ca^{2+}$ increase and apoptosis, whereas dantrolene, an intracellular $Ca^{2+}$ release blocker, completely blocked these actions of ascorbate. In addition, phospholipase C (PLC) inhibitors (U-73122 and manoalide) significantly suppressed the intracellular $Ca^{2+}$ release and apoptosis induced by ascorbate. Collectively, these results suggest that ascorbate induced apoptosis without changes in the cellular redox status in HepG2 cells, and that the PLC-coupled intracellular $Ca^{2+}$ release mechanism may mediate ascorbate-induced apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.1
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• pp.5-9
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• 2013

Rhomboids were identified as the first intramembrane serine proteases about 10 years ago. Since then, the study of the rhomboid protease family has blossomed. Rhomboid domain containing 1 (RHBDD1), highly-expressed in human testis, contains a rhomboid domain with unknown function. In the present study, we tested the hypothesis that RHBDD1 was associated with proliferation and apoptosis in hepatocellular carcinoma using recombinant lentivirus-mediated silencing of RHBDD1 in HepG2 cells. Our results showed that down-regulation of RHBDD1 mRNA levels markedly suppressed proliferation and colony formation capacity of HepG2 human hepatoma cancer cells in vitro, and induced cell cycle arrest. We also found that RHBDD1 silencing could obviously trigger HepG2 cell apoptosis. In summary, it was demonstrated that RHBDD1 might be a positive regulator for proliferative and apoptotic characteristics of hepatocellular carcinoma.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.2
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• pp.963-967
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• 2014

Previous studies have suggested anti-tumor effects of asiatic acid in some human cancer cell lines. This agent is reported to increase the levels of $p21^{WAF1/CIP1}$ in human breast cancer cell lines. However, the molecular mechanisms have not been established. Here we report that asiatic acid up-regulates $p21^{WAF1/CIP1}$ protein expression but not the level of $p21^{WAF1/CIP1}$ mRNA in HepG2 human hepatoma cells. Furthermore, we found that the asiatic acid induced increase of $p21^{WAF1/CIP1}$ protein was associated with decreased phosphorylation (ser-146) of $p21^{WAF1/CIP1}$. Knockdown of NDR1/2 kinase, which directly phosphorylates $p21^{WAF1/CIP1}$ protein at ser-146 and enhances its proteasomal degradation, increased the levels of $p21^{WAF1/CIP1}$ protein and eliminated the regulation of $p21^{WAF1/CIP1}$ stability by asiatic acid. At the same time, the expression of NDR1/2 kinase decreased during treatment with asiatic acid in HepG2 cells. Moreover, asiatic acid inhibited the proliferation of HepG2 cells, this being attenuated by knockdown of $p21^{WAF1/CIP1}$. In conclusion, we propose that asiatic acid inhibits the expression NDR1/2 kinase and promotes the stability of $p21^{WAF1/CIP1}$ protein through attenuating NDR1/2 dependent phosphorylation of $p21^{WAF1/CIP1}$ in HepG2 cells.

• Korean Journal of Plant Resources
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• v.25 no.5
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• pp.647-651
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• 2012

The objective of this study was to investigate the anticancer effects of the extracts of oriental melon seeds. Various solvent extracts of oriental melon seeds were prepared and their anticancer effects were examined using in vitro MTT and CV assays. The anticancer effects of various extracts of oriental melon seeds were also examined in five human cancer cell lines including A549, AGS, HT-29, MCF-7 and HepG2. The ethanol extract of heated oriental melon seeds showed the potent cytotoxic effects especially against mouse hepatoma cell line(Hepa1c1c7), human hepatoma cell line(HepG2) and human breast cancer cell line(MCF-7). These data suggest that oriental melon seeds can be a promising anticancer agent against human liver and breast cancer.

• Journal of the Korean Society of Food Science and Nutrition
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• v.30 no.2
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• pp.372-376
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• 2001

The effect of garlic extract and vitamin C mixture on the various cancer cell lines in vitro and in vivo have been examined. Proliferation of human colon cancer (HT-29), human rectal cancer (HRT-18) and human hepatoma (HepG2) cells was inhibited by garlic extract and vitamin C, respectively. Based on the cytotoxic activity, mixture of garlic extract and vitamin C was demonstrated to possess a synergistic growth inhibition on HT-29, HRT-18 and HepG2 cancer cells. Mixture of garlic extract and vitamin C significantly arrested G2/M phase cells in the HepG2 cell cycle. Oral administration of mixture of garlic extract and vitamin C to sarcoma-180 tumor-bearing mice prolonged survival time compared to that of control group. These results suggested that addition of vitamin C enhances anticancer activity of garlic extract in vitro, and mixture of garlic extract and vitamin C has antitumor effect in vivo.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.4
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• pp.821-828
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• 2008

Onchungeum, a herbal formula, which has been used for treatment of anemia due to bleeding, discharging blood and skin disease. In the present study, it was examined the effects of extract of Onchungeum (OCE) on the growth of human hepatocarcinoma cell lines Hep3B (p53 null type) and HepG2 (p53 wild type) in order to investigate the anti-proliferative mechanism by OCE. Treatment of Hep3B and HepG2 cells to OCE resulted in the growth inhibition in a dose-dependent manner, however Hep3B cell line exhibited a relatively strong anti-proliferative activity to OEC. Flow cytometric analysis revealed that OCE treatment in Hep3B cells caused G1 phase arrest of the cell cycle, which was associated with various morphological changes in a dose-dependent fashion. RT-PCR and immunoblotting data revealed that treatment of OCE caused the down-regulation of cyclin D1 expression, however the levels of cyclin E expression were not changed by OCE. The G1 arrest of the cell cycle was also associated with the induction of Cdk inhibitor p27 by OCE. Because the p53 gene is null in Hep3B cells, it is most likely that the induction of p21 is mediated through a p53-independent pathway. Moreover, p27 detected in anti-Cdk4 and anti-Cdk2 immunoprecipitates from the OCE-treated cells, suggesting that OCE-induced p27 protein blocks Cdk kinase activities by directing binding to the cyclin/Cdk complexes. Furthermore, OCE treatment potently suppresses the phosphorylation of retinoblastoma proteins and the levels of the transcription factor E2F-1 expression. Taken together, these results indicated that the growth inhibitory effect of OCE in Hep3B hepatoma cells was associated with the induction of G1 arrest of the cell cycle through regulation of several major growth regulatory gene products.