• Asian Pacific Journal of Cancer Prevention
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• v.15 no.23
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• pp.10397-10400
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• 2015

Stigmalactam, an aristolactam-type alkaloid extracted from Orophea enterocarpa, exerts cytotoxicity against several human and murine cancer cell lines, but the molecular mechanisms remain elusive. The aims of this study were to identify the mode and mechanisms of human cancer cell death induced by stigmalactam employing human hepatocellular carcinoma HepG2 and human invasive breast cancer MDA-MB-231 cells as models, compared to normal murine fibroblasts. It was found that stigmalactam was toxic to HepG2 and MDA-MB-231 cells with $IC_{50}$ levels of $23.0{\pm}2.67{\mu}M$ and $33.2{\pm}4.54{\mu}M$, respectively, using MTT assays. At the same time the $IC_{50}$ level towards murine normal fibroblast NIH3T3 cells was $24.4{\pm}6.75{\mu}M$. Reactive oxygen species (ROS) production was reduced in stigmalactam-treated cells dose dependently after 4 h of incubation, indicating antioxidant activity, measured by using 2',7',-dichlorohydrofluorescein diacetate and flow cytometry. Caspase-3 and caspase-9 activities were increased in a dose response manner, while stigmalactam decreased the mitochondrial transmembrane potential dose-dependently in HepG2 cells, using 3,3'-dihexyloxacarbocyanine iodide and flow cytometry, indicating mitochondrial pathway-mediated apoptosis. In conclusion, stigmalactam from O. enterocarpa was toxic to both HepG2 and MDA-MB-231 cells and induced human cancer HepG2 cells to undergo apoptosis via the intrinsic (mitochondrial) pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6541-6548
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• 2013

Pigmented rice is mainly black, red, and dark purple, and contains a variety of flavones, tannin, polyphenols, sterols, tocopherols, ${\gamma}$-oryzanols, amino acids, and essential oils. The present study evaluated the cytotoxic effects of purple rice extracts (PREs) combined with chemotherapeutic drugs on human cancer cells and mechanisms of cell death. Methanolic (MeOH) and dichloromethane (DCM) extracts of three cultivars of purple rice in Thailand: Doisaket (DSK), Nan and Payao (PYO), were tested and compared with white rice (KK6). Cytotoxicity was determined by 3-(4, 5-dimethyl)-2, 5-diphenyltetrazolium bromide (MTT) assay in human hepatocellular carcinoma HepG2, prostate cancer LNCaP and murine normal fibroblast NIH3T3 cells. MeOH-PYO-PRE was the most cytotoxic and inhibited HepG2 cell growth more than that of LNCaP cells but was not toxic to NIH3T3 cells. When PREs were combined with paclitaxel or vinblastine, they showed additive cytotoxic effects on HepG2 and LNCaP cells, except for MeOH-PYO-PRE which showed synergistic effects on HepG2 cells when combined with vinblastine. MeOH-PYO-PRE plus vinblastine induced HepG2 cell apoptosis with loss of mitochondrial transmembrane potential (MTP) but no ROS production. MeOH-PYO-PRE-treated HepG2 cells underwent apoptosis via caspase-9 and-3 activation. The level of ${\gamma}$-oryzanol was highest in DCM-PYO-PRE (44.17 mg/g) whereas anthocyanin content was high in MeOH-PYO-PRE (5.80 mg/g). In conclusion, methanolic Payao purple rice extract was mostly toxic to human HepG2 cells and synergistically enhanced the cytotoxicity of vinblastine. Human HepG2 cell apoptosis induced by MeOH-PYO-PRE and vinblastine was mediated through a mitochondrial pathway.

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.640-646
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• 2005

This study was performed for the investigation of anticancer effects of Siegesbeckia glabrescens(SG) on HepG2 cells, a human hepatoma cell line. In the previous study, we examined the involvement of nitric oxide (NO) on anti-proliferative and apoptotic efficacy of SG in vascular smooth muscle cells. The possible mechanism of the apoptotic effects of SG was investigated in HepG2 cells. SG showed potent cytotoxic activity in HepG2 but not chang cells, liver normal cells. SG treatment caused morphological change such as cell shrinkage, nuclei condensation and cell blebbing in HepG2 cells. SG also increased the nitrite production of HepG2 cells in a dose-dependent manner. Furthermore, L-NNA treatment inhibited the anti-proliferative effect of SG. From RT-PCR, SG decreased Bcl-2 but no affected on Bax. Western blot for procaspase-3 and COX-2 showed that degradation of procaspase-3 protein level or inhibition of COX-2 protein expression by SG treatment. In addition, the apoptotic effect of SG was also demonstrated by DNA laddering. In conclusion, SG-induced HepG2 cells death can occur via apoptosis which was dose-dependent, and associated with apoptosis-related Bcl-2/Bax gene expressions, COX-2 inhibition, caspase-3 activation and NO pathway. These results suggest that SG is potentially useful as a chemotherapeutic/chemopreventive agent in hepatocellular carcinoma.

• BMB Reports
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• v.55 no.12
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• pp.633-638
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• 2022

Liver regeneration is a well-known systemic homeostatic phenomenon. The N⁶-methyladenosine (m⁶A) modification pathway has been associated with liver regeneration and hepatocellular carcinoma. m⁶A methyltransferases, such as methyltransferase 3 (METTL3) and methyltransferase 14 (METTL14), are involved in the hepatocyte-specific-regenerative pathway. To illustrate the role of METTL14, secreted from non-parenchymal liver cells, in the initiation phase of liver regeneration, we performed 70% partial hepatectomy (PH) in Mettl14 heterozygous (HET) and wild-type (WT) mice. Next, we analyzed the ratio of liver weight to body weight and the expression of mitogenic stimulators derived from non-parenchymal liver cells. Furthermore, we evaluated the expression of cell cycle-related genes and the hepatocyte proliferation rate via MKI67-immunostaining. During regeneration after PH, the weight ratio was lower in Mettl14 HET mice compared to WT mice. The expressions of hepatocyte growth factor (HGF) and tumor necrosis factor (TNF)-α, mitogens derived from non-parenchymal liver cells that stimulate the cell cycle, as well as the expressions of cyclin B1 and D1, which regulate the cell cycle, and the number of MKI67-positive cells, which indicate proliferative hepatocyte in the late G1-M phase, were significantly reduced in Mettl14 HET mice 72 h after PH. Our findings demonstrate that global Mettl14 mutation may interrupt the homeostasis of liver regeneration after an acute injury like PH by restraining certain mitogens, such as HGF and TNF-α, derived from sinusoidal endothelial cells, stellate cells, and Kupffer cells. These results provide new insights into the role of METTL14 in the clinical treatment strategies of liver disease.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.11
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• pp.6393-6398
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• 2013

In this research, we used $GdCl_3$ (gadolinium chloride) to restrain the function of Kupffer cells and assessed effects on hepatocarcinogenesis and metastasis in the Kunming mouse. A 0.25% $GdCl_3$ solution (10 mg/kg b.w.) was infused via the vena caudalis of each mouse 1 week before inoculation of H22 cells and was continued once per three days. Then we observed the follow indexes 3 weeks after injection of H22 cells: tumor weight, histologic characteristics of tumor tissue by light microscopy, ultramicrostructure of Kupffer cells under the electron microscope, distribution and number of Kupffer cells by histochemical staining, and TNF-${\alpha}$ and IFN-${\gamma}$ levels in blood-serum and liver tissue by ELISA and RT-PCR. MMP-2 protein expression was tested by immunohistochemistry. The $GdCl_3$ pretreatment had no effect on the quantity of Kupffer cells, but clearly restrained their functions, with decrease of TNF-${\alpha}$ and IFN-${\gamma}$ levels and elevation of MMP2. Tumor immunity functions were markedly suppressed and tumor growth was accelerated with appearance of metastasis. Furthermore, survival time of trial mice was shortened.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5397-5402
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• 2013

The rates of morbidity and mortality of hepatocellular carcinoma (HCC) have not lessened because of difficulty in treating tumor metastasis. Mongolian Saussurea involucrata (SIE) possesses various anticancer activities, including apoptosis and cell cycle arrest. However, detailed effects and molecular mechanisms of SIE on metastasis are unclear. Thus, the present study was undertaken to investigate antimetastatic effects on HCC cells as well as possible mechanisms. Effects of SIE on the growth, adhesion, migration, aggregation and invasion of the SK-Hep1 human HCC cell line were investigated. SIE inhibited cell growth of metastatic cells in dose- and time-dependent manners. Incubation of SK-Hep1 cells with $200-400{\mu}g/mL$ of SIE significantly inhibited cell adhesion to gelatin-coated substrate. In the migration (wound healing) and aggregation assays, SIE treated cells showed lower levels than untreated cells. Invasion assays revealed that SIE treatment inhibited cell invasion capacity of HCC cells substantially. Quantitative real time PCR showed inhibitory effects of SIE on MMP-2/-9 and MT1-MMP mRNA levels, and stimulatory effects on TIMP-1, an inhibitor of MMPs. The present study not only demonstrated that invasion and motility of cancer cells were inhibited by SIE, but also indicated that such effects were likely associated with the decrease in MMP-2/-9 expression of SK-Hep1 cells. From these results, it was suggested that SIE could be used as potential anti-tumor agent.

• Environmental Mutagens and Carcinogens
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• v.17 no.2
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• pp.78-91
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• 1997

Peroxisome is a single membrane-bounded organelle found in hepatic parenchymal cells and kidney tubular epithelial cells. A number of enzymes exist in peroxisome contributing to anabolic and catabolic peroxisomal functions. Extramitochontriai $\beta$-oxidation of fatty acid is a major function of peroxisome. Peroxisomes can be proliferated by many structually unrelated compounds such as hypolipidemic drugs, plasticizers, pesticides, some pharmaceutical agents and high fat diet. These chemicals, called peroxisome proliferators, act via the peroxisome proliferator activated receptor, to induce peroxisome proliferation, hepatomegaly and hepatocellular carcinoma in rodent. The clear mechanisms of peroxisome proliferator-induced hepatocarcinogenesis have been not demonstrated. Since they are not genotoxic, biochemical changes or changes in gene expressions may be involved. A free radical theory has been suggested based on the finding of oxidative damages of macromolecules by hydrogen peroxide released in the peroxisomal $\beta$-oxidation of fatty acid. Increased cell proliferation by a peroxisome proliferator has been also thought to be an important factor in the hepatocarcinogenesis as suggested in other cases of nongenotoxic carcinogenesis. The alternation of eicosanoid concentrations by peroxisome proliferators may be important in the peroxisome proliferator-induced hepatocarcinogenesis since peroxisome proliferators decrease the concentration of eicosanoids, and the peroxisome proliferator ciprofibrate-eicosanoid combination is comitogenic and costimulates some mitogenic signals in hepatocytes. All of proposed mechanisms should be considered in the peroxisome prolifrator-induced hepatocarcinogenesis.

• Biomolecules & Therapeutics
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• v.13 no.2
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• pp.113-117
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• 2005

Organosulfur compounds have been shown to exert an anti-cancer activity. In an attempt to develop novel chemopreventive and anti-cancer agents for liver cancer, we synthesized allylthiopyridazine derivatives. We have previously shown that allylthiopyridazine derivatives exert inhibitory effects on proliferation, invasion and migration of SK-Hep-1 hepatocarcinoma cells in vitro. The in vivo anti-tumor effect of 3-methvl-6-allylthiopy-ridazine, named as K6, was also reported. In this study, we further investigated the preclinical anti-cancer efficacy of K6 for hepatocarcinoma using nude mice xenografted with Hep-G2 hepatocellular carcinoma cells. K6(20-100 mg/kg, orally administered everyday for 30 days) markedly decreased the tumor volume of Hep-G2 cell-transplanted nude mice as evidenced by ultrasonographic and plethysmogranhic analyses. The inhibitory effect on tumor volume was lower than that exerted by doxorubicin (2 mg/kg), intravenously injected) which was used as a positive control. This study shows that K6 efficiently suppresses xenograft tumor growth, revealing K6 as apotential anti-cancer agent for suppressing in vivo progression of liver cancer. Given that hepatocarcinoma is among the most prevalent and lethal malignancies and there is no effective treatment to date, our study may contribute to the potential drug development for liver cancer.

• Molecular & Cellular Toxicology
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• v.4 no.1
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• pp.22-30
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• 2008

Malachite Green (MG), a toxic chemical used as a dye, topical antiseptic and antifungal agent for fish, is highly soluble in water, cytotoxic to various mammalian cells and also acts as a liver tumor promoter. In view of its industrial importance and possible exposure to human beings, MG possesses a potential environmental health hazard. So, we performed with HepG2, a human hepatocellular carcinoma cell line, to identify the differentially expressed genes (DEGs) related to toxicity of MG. And we compared gene expression between control and MG treatment to identify genes that are specifically or predominantly expressed by employing annealing control primer (ACP)-based $GeneFishing^{TM}$ method. The cytotoxicity $(IC_{20})$ of MG was determined above the $0.867{\mu}M$ in HepG2 cell for 48 h treatment. And the DEGs of MG were identified that 5 out of 6 DEGs were upregulated and 1 out of 6 DEGs was down-regulated by MG. Also, MG induced late apoptosis and necrosis in a dose dependent in flow cytometric analysis. Through further investigation, we will identify more meaningful and useful DEGs on MG, and then can get the information on mechanism and pathway associated with toxicity of MG.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.20
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• pp.9039-9043
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• 2014

There is a continuing need for innovative alternative therapies for liver cancer. DNA vaccines for hormone/growth factor immune deprivation represent a feasible and attractive approach for cancer treatment. We reported a preventive effect of a DNA vaccine based on six copies of the B cell epitope GRP18-27 with optimized adjuvants against H22 hepatocarcinoma. Vaccination with pCR3.1-VS-HSP65-TP-GRP6-M2 (vaccine) elicited much higher level of anti-GRP antibodies and proved efficacious in preventing growth of transplanted hepatocarcinoma cells. The tumor size and weight were significantly lower (p<0.05) in the vaccine subgroup than in the control pCR3.1-VS-TP-HSP65-TP-GRP6, pCR3.1-VS-TP-HSP65-TP-M2 or saline subgroups. In addition, significant reduction of tumor-induced angiogenesis associated with intradermal tumors of H22 cells was observed. These potent effects may open ways towards the development of new immunotherapeutic approaches in the treatment of liver cancer.