• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.379-387
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• 2009

We have previously reported that N-ethylmaleimide (NEM) induces apoptosis through activation of $K^+$, $Cl^-$-cotransport (KCC) in HepG2 human hepatoblastoma cells. In this study we investigated the possible role of phospholipase $A_2$ ($PLA_2$)-arachidonic acid (AA) signals in the mechanism of the NEM-induced apoptosis. In these experiments we used arachidonyl trifluoromethylketone ($AACOCF_3$), bromoenol lactone (BEL) and p-bromophenacyl bromide (BPB) as inhibitors of the calcium-dependent cytosolic $PLA_2$ ($cPLA_2$), the calcium-independent $PLA_2$ ($iPLA_2$) and the secretory $PLA_2$ ($sPLA_2$), respectively. BEL significantly inhibited the NEM-induced apoptosis, whereas $AACOCF_3$ and BPB did not. NEM increased AA liberation in a dose-dependent manner, which was markedly prevented only by BEL. In addition AA by itself induced $K^+$ efflux, a hallmark of KCC activation, which was comparable to that of NEM. The NEM-induced apoptosis was not significantly altered by treatment with indomethacin (Indo) and nordihydroguaiaretic acid (NDGA), selective inhibitors of cyclooxygenase (COX) and lipoxygenase (LOX), respectively. Treatment with AA or 5,8,11,14-eicosatetraynoic acid (ETYA), a non-metabolizable analogue of AA, significantly induced apoptosis. Collectively, these results suggest that AA liberated through activation of $iPLA_2$ may mediate the NEMinduced apoptosis in HepG2 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.6 no.4
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• pp.187-191
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• 2002

Tamoxifen, an antiestrogen, has previously been shown to induce apoptosis in HepG2 human hepatoblastoma cells through activation of the pathways independent of estrogen receptors, i.e., intracellular $Ca^{2+}$ increase and generation of reactive oxygen species (ROS). However, the mechanism of tamoxifen to link increased intracellular $Ca^{2+}$ to ROS generation is currently unknown. Thus, in this study we investigated the possible involvement of calmodulin, a $Ca^{2+}$ activated protein, and $Ca^{2+}$/calmodulin-dependent protein kinase II in the above tamoxifen-induced events. Treatment with calmodulin antagonists (calmidazolium and trifluoroperazine) or specific inhibitors of $Ca^{2+}$/calmodulin-dependent protein kinase II (KN-93 and KN-62) inhibited the tamoxifen-induced apoptosis in a dose-dependent manner. In addition, these agents blocked the tamoxifen-induced ROS generation in a concentration-dependent fashion, which was completely suppressed by intracellular $Ca^{2+}$ chelation. These results demonstrate for the first time that, despite of its well-known direct calmodulin-inhibitory activity, tamoxifen may generate ROS and induce apoptosis through indirect activation of calmodulin and $Ca^{2+}$/calmodulin-dependent protein kinase II in HepG2 cells.

• The Journal of Korean Medicine
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• v.39 no.4
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• pp.158-170
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• 2018

Objectives: The objective of this study is Korean mistletoe lectin (Viscum album coloratum agglutinin, VCA) and bee venom (BV) to experimental prove comparative study of VCA and BV on the anti-cancer effect and mechanisms of action. Methods: In this study, it was examined in a human hepatocellular carcinoma cell line, Hep G2 cells. Cytotoxic effects of VCA and BV on Hep G2 cells were determined by 3- (4, 5-dimethylthiazol-2-yl) -2, 5-diphenyltetrazolium bromide (MTT) assay in vitro. VCA and BV killed Hep G2 cells in a time- and dose-dependent manner. Results: The apoptotic cell death was then confirmed by propidium iodide staining and DNA fragmentation analysis. The mechanisms of action was examined by the expression of anti-apoptotic proteins and activation of mitogen-activated protein kinases. Treatment of Hep G2 cells with VCA activated poly (ADP-ribose) polymerase-1 (PARP-1) known as a marker of apoptosis, and mitogen-activated protein kinases signaling pathways including SAPK/JNK, MAPK and p38. BV also activated PARP-1, MAPK, p38 but not JNK. The expression level of anti-apoptotic molecule, Bcl-X, was decreased by VCA treatment but not BV. Finally, the phosphorylation level of ERM proteins involved in the cytoskeleton homeostasis was decreased by both stimuli. Conclusion: We examined the involvement of kinase in VCA or BV - induced apoptosis by using kinase inhibitors. VCA-induced apoptosis was partially inhibited by in the presence.

• Journal of Microbiology and Biotechnology
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• v.9 no.4
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• pp.504-508
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• 1999

This report compares the selective cytotoxic effects of Doenjang fermented by various Bacillus strains (Bacillus sp. SS9, SSA3, and PM3) on human liver cell lines with that of conventional Doenjang (DTY, DTG, and DTK) and commercial Doenjang (DCM, DCD, and DCS). To investigate selective cytotoxic effects of Doenjang extracts, the cell density of HepG2 (Hepatocellular carcinoma) and CCL-13 (cells derived from human normal liver) was estimated after addition of the extracts by using a viable cell counting method. The maximum selectivity ratio ($IC_{50}$value against CCL-13/$IC_{50}$ value aganist HepG2) was observed by PM3 (extracts of Doenjang fermented with Bacillus sp. PM3). As for morphological changes shown by the addition of PM3 into HepG2 and CCL-13 cultures, HepG2 was significantly disrupted, however, CCL-13 was not affected. Also, the growth rate of HepG2 was decreased significantly by the addition of PM3. Consequently, PM3 showed a more detrimental effect on HepG2 than that on CCL-13.

• Journal of Physiology & Pathology in Korean Medicine
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• v.24 no.3
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• pp.457-462
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• 2010

The purpose of this study is to investigate the effect of water extract from Artemisiae Argi Folium Fermented with Lactobacillus pentosus (AFL) on viability of human hepatocyte HepG2 cells treated with hepatotoxicants such as EtOH, gallic acid, nicotine, acetaminophen, acetaldehyde, and lipopolysaccharide. AFL (0~400 ug/mL) was treated with EtOH, gallic acid, nicotine, acetaminophen, acetaldehyde, and lipopolysaccharide. And the viability of HepG2 cells was measured by MTT assay. AFL at the high concentration such as 400 ug/mL showed to increase significantly viabilities of HepG2 cells compared with hepatotoxicants (EtOH, gallic acid, nicotine, acetaminophen, and lipopolysaccharide) only (p<0.05). AFL could be supposed to have the hepatoprotective effect against hepatotoxicants such as gallic acid, EtOH, nicotine, acetaminophen, and lipopolysaccharide at the high concentration.

• Korean Journal of Pharmacognosy
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• v.48 no.4
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• pp.273-279
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• 2017

The aim of this study was to investigate the mechanisms underlying apoptosis induced by a broussochalcone B (BCB) from Broussonetia papyrifera in HepG2 cells. The results showed that BCB treatment for 24 hr significantly inhibited cell viability in a dose-dependent manner, and induced apoptosis in HepG2 cells. More so, BCB treatment triggered the cleavage of caspase-8, -9, -3, poly (ADP-ribose) polymerase (PARP), increase of Bax level, and decrease of Bcl-2 expression. A general caspase inhibitor (z-VAD-fmk) blocked BCB-induced cell death. Furthermore, BCB treatment caused reactive oxygen species (ROS) production in a dose-dependent manner. In addition, an antioxidant N-acetylcysteine (NAC) blocked BCB-induced ROS production and cell death. Therefore, these results indicate that BCB-induced apoptosis is mediated by a caspase dependent pathway and ROS production in HepG2 cells.

• BMB Reports
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• v.46 no.12
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• pp.611-616
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• 2013

Luteolin-7-O-glucoside (LUT7G), a flavone subclass of flavonoids, has been found to increase anti-oxidant and anti-inflammatory activity, as well as cytotoxic effects. However, the mechanism of how LUT7G induces apoptosis and regulates cell cycles remains poorly understood. In this study, we examined the effects of LUT7G on the growth inhibition of tumors, cell cycle arrest, induction of ROS generation, and the involved signaling pathway in human hepatocarcinoma HepG2 cells. The proliferation of HepG2 cells was decreased by LUT7G in a dose-dependent manner. The growth inhibition was due primarily to the G2/M phase arrest and ROS generation. Moreover, the phosphorylation of JNK was increased by LUT7G. These results suggest that the anti-proliferative effect of LUT7G on HepG2 is associated with G2/M phase cell cycle arrest by JNK activation.

• Molecular & Cellular Toxicology
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• v.4 no.3
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• pp.183-191
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• 2008

Volatile organic compounds (VOCs) are common constituents of cleaning and degreasing agents, paints, pesticides, personal care products, gasoline and solvents. And VOCs are evaporated at room temperature and most of them exhibit acute and chronic toxicity to human. Benzene is the most widely used prototypical VOC and the toxic mechanisms of them are still unclear. The multi-step process of toxic mechanism can be more fully understood by characterizing gene expression changes induced in cells by toxicants. In this study, DNA microarray was used to monitor the expression levels of genes in HepG2 cells and HL-60 cells exposed to the benzene on IC20 and IC50 dose respectively. In the clustering analysis of gene expression profiles, although clusters of HepG2 and HL-60 cells by benzene were divided differently, expression pattern of many genes observed similarly. We identified 916 up-regulated genes and 1,144 down-regulated genes in HepG2 cells and also 1,002 up-regulated genes and 919 down-regulated genes in HL-60 cells. The gene ontology analysis on genes expressed by benzene in HepG2 and HL-60 cells, respectively, was performed. Thus, we found some principal pathways, such as, focal adhesion, gap junction and signaling pathway in HepG2 cells and toll-like receptor signaling pathway, MAPK signaling pathway, p53 signaling pathway and neuroactive ligand-receptor interaction in HL-60 cells. And we also found 16 up-regulated and 14 down-regulated commonly expressed total 30 genes that belong in the same biological process like inflammatory response, cell cycle arrest, cell migration, transmission of nerve impulse and cell motility in two cell lines. In conclusion, we suggest that this study is meaningful because these genes regarded as strong potential biomarkers of benzene independent of cell type.

• 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.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.1
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• pp.137-142
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• 2016

We investigated the anti-proliferative effects of solar salt and purified salt (PS) on HepG2 human hepatocellular cancer cells as well as their effects on mRNA and protein expression of apoptosis- and cell cycle-related genes, including Bcl-2, Bax, p53, and p21. Each salt sample suppressed cancer cell proliferation when treated at a concentration of 0.5% or 1%. Especially solar salt from T salt field (SS-T) and solar salt from Y salt field (SS-Y) significantly suppressed proliferation of cancer cells in comparison with PS. Treatment of HepG2 cells with salt samples at a concentration of 1% suppressed expression of Bcl-2 and promoted expression of Bax, p53, and p21 at the mRNA and protein levels in comparison with the control group. Inductively coupled plasma optical emission spectrometry (ICP-OES) showed that SS-T and SS-Y had higher concentrations of Ca, Mg, S, and K than PS, and SS-T contained higher concentrations of these minerals than SS-Y. It seems that Na and mineral contents in solar salt may contribute to regulation of the genes. Taken together, salt, especially mineral rich solar salt, inhibits cancer cell growth by regulating apoptosis and cell cycle-related genes.