• Journal of Microbiology
• /
• v.37 no.2
• /
• pp.90-96
• /
• 1999

The core protein of the hepatitis C virus (HCV) is a multifunctional protein. The HCV core protein was reported to regulate cellular gene expression and transform primary rat embryo fibroblast cells. However, the role of the core protein in the pathogenesis of HCV-associated liver diseases is not well understood. To investigate the functional role of the core protein in cytophathogenicity, we have constructed stable expression systems of full length or truncated HCV core protein lacking the C-terminal hyderophobic domains and established HepG2 cell clones constitutively expressing the core protein. The full length core protein was localized in the cytoplasm and the C-terminal truncated core protein was localized in the nucleus. HepG2 cells expressing nuclear, truncated core protein showed elevated cell death during cultivation compared to untransfected cells and full length core-expressing cells. In the treatment with bleomycin, both cell clones expressing full length or truncated core protein appeared to be more sensitive to blemoycin than the parental HepG2 cells. These results suggest that the core protein may play a role in HCV pathogenesis promoting apoptotic cell death of infected cells.

• Journal of Microbiology and Biotechnology
• /
• v.15 no.6
• /
• pp.1310-1316
• /
• 2005

To evaluate the toxicological properties of human cytochrome P450 2E1 (CYP2E1) induced by ethanol and possible protective effects of various green tea catechins on alcohol-induced toxicity, transfected HepG2 cells that stably and constitutively express human CYP2E1 were established using the recombinant retroviral expression vector. Exposure of the CYP2E1-expressing HepG2 cells to high concentration of ethanol (200 mM) for 5 days resulted in a more than $50\%$ increase of cytotoxicity, assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) reduction, lactate dehydrogenase (LDH) release, and reactive oxygen species (ROS) production, and loss of normal morphology, in comparison with HepG2 cells containing control vector. Treatment of the cells with various catechins increased cell viability by more than 2-fold. (-)-Epicatechin gallate and(-)-catechin gallate at the lowest concentration ($5\;{\mu}M$) attenuated cell death induced CYP2E1 by $60-65\%$. Therefore, the results showed that the catechins, including epimerized catechins, have strong protective effects against alcohol-induced CYP2E1 toxicity, and it is correlated with antioxidant effect.

• KSBB Journal
• /
• v.30 no.4
• /
• pp.175-181
• /
• 2015

Cells proliferate via repeating process that growth and division. This process is G1, S, G2 and M four phases consists. Monitoring the progression of the cell cycle is a specific step that to be a continuous process is repeated to adjust the start of the next step. At this time, this process is called a Checkpoint. Currently, there are three known checkpoints that G1-S phase, G2-M phase, and the M phase. In this study, we confirmed that cell cycle arrest effects by ethanol extracts of Artemisia annua Linne (AAE) in Hep3B liver cancer cells. AAE was regulated proteins which involved in cell cycle such as pAkt, pMDM2, p53, p21, pCDK2 (T14/Y15). AAE induced cell cycle arrest in G1 checkpoint through phosphorylation of CDK2. Akt and p53 upstream is inhibited by AAE and p53 activated by non-activated pMDM2, p53 inhibitor. Thereby, activated p53 is transcript to p21 and activated p21 protein is combined with Cyclin E-pCDK2 complex. Therefore, we confirmed that AAE-induced cell cycle arrest was occurred by p21-Cyclin E-pCDK2 complex by inhibition of pAkt signal. Because of this cell cycle can't pass to S phase from G1 phase.

• Microbiology and Biotechnology Letters
• /
• v.47 no.1
• /
• pp.43-53
• /
• 2019

The anticancer activity of guava (Psidium guajava L.) leaf extract (GLE) occurs via the induction of apoptosis in cancer cells. However, the mechanism behind GLE-induced apoptosis in the human hepatocellular carcinoma cell line HepG2 remains unclear. In the present study, we investigated the apoptotic effects and mechanism of action of GLE in cultured HepG2 cells. The results showed that GLE induced reactive oxygen species (ROS) synthesis and disrupted the mitochondrial membrane potential (${\Delta}{\Psi}m$). Moreover, GLE increased the expression of apoptotic pathway proteins, such as the cleaved forms of caspase-3, -8, and -9; the translocation of Bax and cytochrome c (cyt-c) from the mitochondria to the cytosol; and the downregulation of Bcl-2. In addition, p53 protein expression was increased upon GLE treatment. These observations indicate that the GLE-induced apoptosis in HepG2 cells is mediated by mitochondrial ROS generation, followed by caspase activation and cyt-c release, suggesting that GLE may be a promising candidate for the development of novel drugs for the treatment of liver cancers.

• Journal of Life Science
• /
• v.20 no.6
• /
• pp.877-884
• /
• 2010

We investigated the growth inhibitory effect of internal organs of Aplysia kurodai (AK) on proliferation in cancer cell lines in vitro. The internal organs of AK were extracted with methanol (AKM), which were then further fractionated into four subfractions by using solvent partition method, resulting in hexane (AKMH), methanol (AKMM), butanol (AKMB), and aqueous (AKMA) soluble fractions. We determined the cytotoxic effect of these four fractions in four kinds of cancer cell lines - HepG2, MCF-7, HT29 and B16-F10 - by MTT assay. Among the four subfractions of AKM, AKMM showed the strongest cytotoxic effects on all cancer cell lines which were used. Morphological changes such as membrane shrinking and blebbing of cells were also observed in AKMM treatment in HepG2 cells. In addition, we also observed quinone reductase (QR) induced effect in the methanol layer (AKMM) of HepG2 cells. AKMM showed the highest induction activity of quinone reductase on HepG2 cells among the partition layers. The QR induced effect of AKMM was determined to be 2.4 at $100\;{\mu}g/ml$ level with a control value of 1.0. Although further studies are needed, the present work suggests that internal organs of Aplysia kurodai (AK) may be a chemopreventive agent for the treatment of human cells.

• Korean Journal of Food Science and Technology
• /
• v.34 no.4
• /
• pp.688-693
• /
• 2002

The anticarcinogenic effects of various food components have received much attention in recent years. However mechanism of anticarcinogens in food materials on cancer cells have rarely been investigated. This study was performed to investigate the effects on the cytotoxicity and quinone reductase (QR) activity of Allium tuberusum (AT) on the human cancer cells. The six partition layers which are methanol (ATM), hexane (ATMH), ethylether (ATMEE), ethylacetate (ATMEA), butaonl (ATMB) and aqueous (ATMA) of Allium tuberusum were screened for their cytotoxic effects on HepG2, MCF-7, HeLa and SK-N-MC cells by the MTT assay. Among the six partition layers, ATMEE had the strongest cytotoxic effect at concentration of $150\;{\mu}g/mL$ which resulted over 95% on HepG2, HeLa, MCF-7 and SK-N-MC cell lines. The ATMEA also showed significant cytotoxic effect on HepG2 and SK-N-MC cell lines. The ATMB showed the highest induction activity of QR on HepG2 cells among the other partition layers. QR activity of HepG2 cells, grown in the presence of ATMB at the concentration of $50\;{\mu}g/mL$, was increased by 3.9 times, compared to the control value of 1.0. Based on these results, the ATMEE and ATMB may have potentially anticarcinogenic and chemopreventive activities.

• Biomolecules & Therapeutics
• /
• v.27 no.6
• /
• pp.540-552
• /
• 2019

To determine the chemopreventive potential of alyssin and iberin, the in vitro anticancer activities and molecular targets of isothiocyanates (ITCs) were measured and compared to sulforaphane in hepatocellular carcinoma cell HepG2. The SR-FTIR spectra observed a similar pattern vis-a-vis the biomolecular alteration amongst the ITCs-treated cells suggesting a similar mode of action. All of the ITCs in this study cause cancer cell death through both apoptosis and necrosis in concentration dependent manner ($20-80{\mu}M$). We found no interactions of any of the ITCs studied with DNA. Notwithstanding, all of the ITCs studied increased intracellular reactive oxygen species (ROS) and suppressed tubulin polymerization, which led to cell-cycle arrest in the S and $G_2/M$ phase. Alyssin possessed the most potent anticancer ability; possibly due to its ability to increase intracellular ROS rather than tubulin depolymerization. Nevertheless, the structural influence of alkyl chain length on anticancer capabilities of ITCs remains inconclusive. The results of this study indicate an optional, potent ITC (viz., alyssin) because of its underlying mechanisms against hepatic cancer. As a consequence, further selection and development of effective chemotherapeutic ITCs is recommended.

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

• Food Science and Biotechnology
• /
• v.17 no.6
• /
• pp.1332-1336
• /
• 2008

The water extract of Saururus chinensis was investigated for oxygen radical absorbance capacity (ORAC), reducing capacity, metal chelating activity, and intracellular antioxidant activity using HepG2 cell. When 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH) was used for the generation of peroxyl radicals in vitro, S. chinensis extract (SC-E) showed the strong and concentration-dependent scavenging activity through donating protons which could be explained by its reducing property. When hydroxyl radicals were generated in vitro through the addition of $Cu^{2+}$ and $H_2O_2$, SC-E demonstrated the antioxidant activity depending on its concentration. In HepG2 cell model, most of intracellular oxidative stress generated by AAPH was efficiently removed by SC-E. However, when $Cu^{2+}$ without $H_2O_2$ was used as an oxidant in the intracellular assay, SC-E partially reduced the oxidative stress caused by $Cu^{2+}$ in cellular antioxidant activity assay system. These results indicate that SC-E could be utilized for the development of functional foods as antioxidant resource in the near future.

• Asian Pacific Journal of Cancer Prevention
• /
• v.14 no.3
• /
• pp.1829-1832
• /
• 2013

In the present study, investigations were carried out to screen the anticancer activities of fenugreek seed oil against cancer cell lines (HEp-2, MCF-7, WISH cells), and a normal cell line (Vero cells). Cytotoxicity was assessed with MTT and NRU assays, and cellular morphological alterations were studied using phase contrast light microscopy. All cells were exposed toi 10-1000 ${\mu}g/ml$ of fenugreek seed oil for 24 h. The results show that fenugreek seed oil significantly reduced the cell viability, and altered the cellular morphology in a dose dependent manner. Among the cell lines, HEp-2 cells showed the highest decrease in cell viability, followed by MCF-7, WISH, and Vero cells by MTT and NRU assays. Cell viability at 1000 ${\mu}g/ml$ was recorded as 55% in HEp-2 cells, 67% in MCF-7 cells, 75% in WISH cells, and 86% in Vero cells. The present study provides preliminary screening data for fenugreek seed oil pointing to potent cytotoxicity against cancer cells.