• Journal of Life Science
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• v.17 no.10
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• pp.1447-1451
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• 2007

Through the screening of marine natural compounds that inhibit cancer cell proliferation, we previously reported that pectenotoxin-2 (PTX-2) isolated from marine sponges exhibits selective cytotoxicity against several cell lines in p53-deficient tumor cells compared to those with functional p53. However, the molecular mechanisms of its anti-proliferative action on malignant cell growth are not completely known. To further explore the mechanisms of its anti-cancer activity and to test whether the status of p53 in liver cancer cells correlates with their chemo-sensitivities to PTX-2, we used two well-known hepatocarcinoma cell lines, p53-deficient Hep3B and p53-wild type HepG2. We have demonstrated that PTX-2 markedly inhibits Hep3B cell growth and induces apoptosis whereas HepG2 cells are much more resistant to PTX-2 suggesting that PTX-2 seems to act by p53-independent cytotoxic mechanism. The apoptosis induced by PTX-2 in Hep3B cells was associated with the modulation of DNA fragmentation factor (DFF) family proteins, up-regulation of pro-apoptotic Bcl-2 family members such as Bax and Bcl-xS and activation of caspases (caspase-3, -8 and -9). Blockade of the caspase-3 activity by caspase-3 inhibitor, z-DEVD-fmk, prevented the PTX-2-induced growth inhibition in Hep3B cells. Moreover, treatment with PTX-2 also induced phosphorylation of AKT and extracellular-signal regulating kinase (ERK), but not c-Jun N-terminal kinase (JNK) and p38 mitogen-activated protein kinase (MARK). Specific inhibitors of PI3K inhibitor (LY294002) and ERK1/2 inhibitor (PD98059) significantly blocks PTX-2-induced-anti-proliferative effects, whereas a JNK inhibitor (SP600125) and a p38 MAPK inhibitor (SB203580) have no significant effects demonstrating that the pro-apoptotic effect of PTX-2 mediated through activation of AKT and ERK signal pathway in Hep3B cells.

• Food Science and Biotechnology
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• v.17 no.5
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• pp.1086-1091
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• 2008

The antioxidant activities of the extracts of dangyuja (Citrus grandis Osbeck) leaves were evaluated. The highest phenolic content was obtained from the ethyl acetate fraction (EF) (202.1$\pm$0.8 mg GAE/g dried extract) and it exhibited the highest 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The cytoprotective effects of EF on oxidative damage induced by tert-butyl hydroperoxide (t-BHP) in a human hepatoma cell line, HepG2 cells, were investigated to understand the intracellular antioxidant mechanisms. Treatment of HepG2 cells with EF prior to oxidative stress was found to inhibit reactive oxygen species (ROS) generation, lipid peroxidation, and DNA damage in a dose-dependent manner. Gas chromatography-mass spectrometry (GC-MS) studies on EF resulted in tentative identification of 19 compounds representing 94.3% of the total content. Taken together, these results demonstrated that EF has excellent antioxidant activities and thus dangyuja leaves have great potential as a source for natural antioxidant which can be applied in food products.

• 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.

• Journal of Physiology & Pathology in Korean Medicine
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• v.16 no.4
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• pp.684-692
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• 2002

Cordyceps militaris has been known as a Chinese traditional medicine for the treatment of tuberculosis, asthma, kidney disease, debility and fatigue etc. This study was attempted to investigate the therapeutic effect of C. militaris extract on the cytotoxic activity of HepG2, human hepatocellular carcinoma cells and the liver damage induced by carbon tetrachloride in SD rats. C. militaris extracts inhibited significantly the proliferation of HepG2 cells in vitro. Carbon tetrachloride(CCl₄) caused a significant an increase in liver weight, serum aspartate aminotransferase(AST) and alanine aminotransferase(ALT) activity, alkaline phosphatase(ALP), serum thiobarbituric acid reactive substances (TBARS), microsomal TBARS, and decrease in microsomal detoxification enzymes (cytochrome P-450, P-450 reductase, cytochrome b5, b5 reductase). TBARS and ALP in serum pretreated with C. militaris extracts (300mg/kg/day, 600mg/kg/day) was significantly reduced compared to control group(CCl₄). Cytochrome b5 and b5 reductase activities were significantly increased in CM300 (300 mg/kg/day) and CM600 group(600 mg/kg/day), and cytochrome P-450 reductase was significantly increased in CM300 group. Pretreatment (100, 300, and 600 mg/kg/day for 7 days) of C. militaris with CCl₄ was significantly inhibited the accumulation microsomal TBARS and the significantly increased in the cytochrome P-450 activity. These results suggested that C. militaris (300mg/kg/day for 7 days) has appreciable therapeutic effect on CCl₄ induced hepatotoxicity.

• BMB Reports
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• v.42 no.6
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• pp.344-349
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• 2009

Angiogenesis is crucial for solid tumor growth. By secreting angiogenic factors, tumor cells induce angiogenesis. However, targeting these angiogenic factors for cancer therapy is not always successful, suggesting that other factors may be involved in tumor angiogenesis. This work shows that 25 protein spots were differentially expressed by two-dimensional gel electrophoretic analysis when HepG2 cells induced endothelial cell differentiation to tube in vitro, and most of them were upregulated. Twenty-one proteins were identified with MALDITOF-MS, and the other four were identified by LTQ-MS/MS. Keratins were identified as one class of these upregulated proteins. Further study indicated that the expression of keratin 17 in cultured endothelial cells is likely microenvironment regulated, because its expression can be induced by HepG2 cells and bFGF as well as serum in culture media. Increased expression of keratins in endothelial cells, such as keratin 17, may contribute to the angiogenesis induced by HepG2 cells.

• Toxicological Research
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• v.20 no.3
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• pp.205-211
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• 2004

Concern that some chemicals in our environment may affect human health by disrupt-ing normal endocrine function has prompted a research on interactions of environmental contaminants with steroid hormone receptor. Toxaphene and chlordane are among the 12 persistent organic pollutants identified by the United Nations Environment Programme as requiring urgent attention. We compared the estrogenic activity of two organochlorine pesticides, toxaphene and chlordane, at estrogen receptor a (ER$\alpha$) and estrogen receptor $\beta$ (ER$\beta$). Human hepatoma cells (HepG2) were transiently transfected with rat ER$\alpha$ or ER$\beta$ plus an estrogen-responsive complement C3-luciferase (C3-Luc) reporter gene. After transfection, cells were treated with various concentrations of toxaphene and chlordane to investigate agonism or antagonism of these chemicals. Both toxaphene and chlordane were potent agonists in HepG2 cells for ER$\alpha$. In contrast, these chemicals had a minimal agonist activity with ER$\beta$ and almost abolished 17$\beta$-estradiol-induced ER$\beta$-mediated activity. Therefore, toxaphene and chlordane behaved as an ER$\alpha$ agonist and an ER$\beta$ antagonist with estrogen-responsive reporter plasmid C3-Luc, and exposure to these organochlorine pesticides could have a crictical effect on normal endocrine function.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7137-7141
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• 2013

Several studies have shown that nemo-like kinase (NLK) plays a vital role in apoptosis of cancer cells. The present research concerned effects and mechanisms of Taxol on NLK knockdown human laryngeal cancerHep-2 cell lines in vitro. Using RNAi, methyl-thiazoltetrazolium (MTT) assays, real-time RT-PCR, Western blotting and flow cytometry analysis, growth and the cell cycle progression of NLK knockdown Hep-2 cells and expression of downstream molecules were observed. Cell growth was obviously suppressed in the Taxol treated group (P<0.001, 48 hours). Cell numbers of combined Taxol-based chemotherapy with lentivirus mediated RNAi treatment group (Lv-shNLK+Taxol goup) were significantly different from NLK-specific siRNA lentivirus infected group (Lv-shNLK group) (p<0.001). Flow cytometry analysis revealed that Lv-shNLK+Taxol caused the G0/G1-phase DNA content to decrease from 44.1 to 3.33% (p<0.001) and the S-phase DNA content to increase from 38.4 to 82.0% (p<0.001), in comparison with the Lv-shNLK+Taxol group. Immunoblot analysis showed that knockdown of NLK led to significant reduction in the levels of cyclin D1, PCNA and PARP, whereas cyclin B1 was elevated in. Cell growth was also obviously suppressed in the Hep-2 cell line, knockdown of NLK making them more sensitive to Taxol treatment. NLK is expected to become a target of new laryngeal cancer gene therapies.

• BMB Reports
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• v.46 no.10
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• pp.513-518
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• 2013

We investigated the protective effects of Gymnaster koraiensis against oxidative stress-induced hepatic cell damage. We used two different cytotoxicity models, i.e., the administration of tert-butyl hydroperoxide (t-BHP) and acetaminophen, in HepG2 cells to evaluate the protective effects of G. koraiensis. The ethyl acetate (EA) fraction of G. koraiensis and its major compound, 3,5-di-O-caffeoylquinic acid (DCQA), exerted protective effects in the t-BHP-induced liver cytotoxicity model. The EA fraction and DCQA ameliorated t-BHP-induced reductions in GSH levels and exhibited free radical scavenging activity. The EA fraction and DCQA also significantly reduced t-BHP-induced DNA damage in HepG2 cells. Furthermore, the hexane fraction of G. koraiensis and its major compound, gymnasterkoreayne B (GKB), exerted strong hepatoprotection in the acetaminophen-induced cytotoxicity model. CYP 3A4 enzyme activity was strongly inhibited by the extract, hexane fraction, and GKB. The hexane fraction and GKB ameliorated acetaminophen-induced reductions in GSH levels and protected against cell death.

• Journal of Life Science
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• v.25 no.9
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• pp.984-992
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• 2015

Sanguinarine is a benzophenanthridine alkaloid originally isolated from the roots of Sanguinaria canadensis. It has multiple biological activities (e.g., antioxidant and antiproliferative) and immune-enhancing potential. In this study, we explored the proapoptotic properties and modes of action of sanguinarine in human hepatocellular carcinoma HepG2 cells. Our results revealed that sanguinarine inhibited HepG2 cell growth and induced apoptosis in a dose-dependent manner. The induction of apoptosis by sanguinarine was associated with the up-regulation of Fas and Bax, the release of cytochrome c from the mitochondria to the cytosol, and the loss of the mitochondrial membrane potential. In addition, sanguinarine activated caspase-9 and -8, initiator caspases of the intrinsic and death extrinsic pathways, respectively, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose) polymerase. Sanguinarine also triggered the generation of reactive oxygen species (ROS). The elimination of ROS by N-acetylcysteine reversed sanguinarine-induced apoptosis. Furthermore, sanguinarine induced the dephosphorylation of Akt and the phosphorylation of mitogen-activated protein kinases, including extracellular signal-regulated kinase (ERK), c-jun N-terminal kinase (JNK), and p38. The growth inhibition was enhanced by the combined treatment of sanguinarine with a phosphatidylinositol 3'-kinase (PI3K) inhibitor and an ERK inhibitor but not JNK and p38 inhibitors. Overall, our data indicate that the proapoptotic effects of sanguinarine in HepG2 cells depend on ROS production and the activation of both intrinsic and extrinsic signaling pathways, which is mediated by blocking PI3K/Akt and activating the ERK pathway. Thus, our data suggest that sanguinarine may be a natural compound with potential for use as an antitumor agent in liver cancer.

• Korean Journal of Food Science and Technology
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• v.43 no.6
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• pp.787-790
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• 2011

The objective of this study was to investigate the anticancer effects of Acer tegmentosum M. extracts. HepG2 hepatocarcinoma cells were treated with ethanol, chloroform, ethylacetate, butanol, aqueous fraction and hot water extract. The antiproliferative effect was evaluated by trypan blue exclusion, MTT-based viability assay and morphology. The trypan blue test showed that anticancer effect of the A. tegmentosum M. extracts on HepG2 cells increased gradually in proportion to the increasing concentration of the fractions. The butanol fraction showed the highest anticancer activity against HepG2 cells (p<0.05). The MTT assay indicated that the growth inhibition by the butanol fraction was dose-dependent. These results suggest that A. tegmentosum M. has the potential to inhibit the growth of hepatocarcinoma cells.