• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.239-244
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• 2014

Several recent studies have showed that the n-myc downstream regulated gene 2 (NDRG2) is a new tumor suppressor gene, and that it plays an important role in tumor suppression in several cancers or cancer cell lines. However, few studies focused on its function in neuroblastoma cells. In the present investigation, we demonstrated that NDRG2 overexpression inhibited their proliferation. Using a cDNA microarray, we found that overexpression of NDRG2 inhibited the expression of cysteine-rich protein 61 (CYR61), a proliferation related gene. From our research, CYR61 may partially hinder NDRG2-mediated inhibition of cell proliferation. Overexpression of NDRG2 resulted in accumulation of cells in the G1 phase, which was accompanied by upregulation of p21 and p27 and downregulation of CDK4 and cyclin D1. Taken together, these data indicate that NDRG2 inhibits the proliferation of neuroblastoma cells partially through suppression of CYR61. Our findings offer novel insights into the physiological roles of NDRG2 in neuroblastoma cell proliferation, and NDRG2 may prove to be effective candidate for the treatment of children with neuroblastoma.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.10
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• pp.4271-4274
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• 2014

The epithelial to mesenchymal transition (EMT) is a key step during embryonic morphogenesis and plays an important role in drug resistance and metastasis in diverse solid tumors. We previously reported that 48 h treatment of anti-cancer drug doxorubicin could induce EMT in human gastric cancer BGC-823 cells. However, the long term effects of this transient drug treatment were unknown. In this study we found that after 48 h treatment with $0.1{\mu}g/ml$ doxorubicin, most cells died during next week, while a minor population of cells survived and formed colonies. We propagated the surviving cells in drug free medium and found that these long term cultured drug survival cells (abbreviated as ltDSCs) retained a mesenchymal-like cell morphology, and expressed high levels of EMT-related molecules such as vimentin, twist and ${\beta}$-catenin. The expression of chromatin reprogramming factors, Oct4 and c-myc, were also higher in ltDSCs than parental cells. We further demonstrated that the protein level of p300 was upregulated in ltDSCs, and inhibition of p300 by siRNA suppressed the expression of vimentin. Moreover, the ltDSCs had higher colony forming ability and were more drug resistant when compared to parental cells. Our results suggested that an epigenetic mechanism is involved in the EMT of ltDSCs.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.3
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• pp.1553-1564
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• 2016

Identification of novel therapeutics in glioblastoma remains crucial due to the devastating and infiltrative capacity of this malignancy. The current study was aimed to appraise effect of arsenic trioxide (ATO) in U87MG cells. The results demonstrated that ATO induced apoptosis and impeded proliferation of U87MG cells in a dose-dependent manner and also inhibited classical NF-${\kappa}B$ signaling pathway. ATO further upregulated expression of Bax as an important proapoptotic target of NF-${\kappa}B$ and also inhibited mRNA expression of survivin, c-Myc and hTERT and suppressed telomerase activity. Moreover, ATO significantly increased adhesion of U87MG cells and also diminished transcription of NF-${\kappa}B$ down-stream targets involved in cell migration and invasion, including cathepsin B, uPA, MMP-2, MMP-9 and MMP-14 and suppressed proteolytic activity of cathepsin B, MMP-2 and MMP-9, demonstrating a possible mechanism of ATO effect on a well-known signaling in glioblastoma dissemination. Taken together, here we suggest that ATO inhibits survival and invasion of U87MG cells possibly through NF-${\kappa}B$-mediated inhibition of survivin and telomerase activity and NF-${\kappa}B$-dependent suppression of cathepsin B, MMP-2 and MMP-9.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7943-7957
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• 2015

Background and Aims: Colorectal cancer is one of the leading causes of death in the world. The aim of this study was to investigate the growth-suppression potentiality of a crude saponin extract (CSENS) prepared from medicinal herb, Nigella sativa, on human colon cancer cells, HCT116. Materials and Methods: HCT116 cells were subjected to increasing doses of CSENS for 24, 48 and 72 h, and then harvested and assayed for cell viability by WST-1. Flow cytometry analyses, cell death detection ELISA, fluorescent stains (Hoechst 33342 and acridine orange/ethidium bromide), DNA laddering and comet assays were carried out to confirm the apoptogenic effects of CSENS. Luciferase reporter gene assays, quantitative reverse transcription-polymerase chain reaction and Western blot analyses were performed to assess the impact of CAERS and CFEZO on the expression levels of key regulatory proteins in HCT116 cells. Results: The results demonstrated that CSENS inhibited proliferation and induced apoptosis. Apoptosis was confirmed by flow cytometry analyses, while CSENS-treated cells exhibited morphological hallmarks of apoptosis including cell shrinkage, irregularity in cellular shape, cellular detachment and chromatin condensation. Biochemical signs of apoptosis, such as DNA degradation, were observed by comet assay and gel electrophoresis. The pro-apoptotic effect of CSENS was caspase-3-independent and associated with increase of the Bax/Bcl-2 ratio. CSENS treatment down-regulated transcriptional and DNA-binding activities of NF-${\kappa}B$ and AP-1 proteins, associated with down-regulation of their target oncogenes, c-Myc, cyclin D1 and survivin. On the other hand, CSENS up-regulated transcriptional and DNA-binding activities of Nrf2 and expression of cytoprotective genes. In addition, CSENS modulated the expression levels of ERK1/2 MAPK, p53 and p21. Conclusions: These findings suggest that CSENS may be a valuable agent for treatment of colon cancer.

• Development and Reproduction
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• v.20 no.2
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• pp.141-147
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• 2016

Rad51 is a key component of homologous recombination (HR) to repair DNA double-strand breaks and it forms Rad51 recombinase filaments of broken single-stranded DNA to promote HR. In addition to its role in DNA repair and cell cycle progression, Rad51 contributes to the reprogramming process during the generation of induced pluripotent stem cells. In light of this, we performed reprogramming experiments to examine the effect of co-expression of Rad51 and four reprogramming factors, Oct4, Sox2, Klf4, and c-Myc, on the reprogramming efficiency. Co-expression of Rad51 significantly increased the numbers of alkaline phosphatase-positive colonies and embryonic stem cell-like colonies during the process of reprogramming. Co-expression ofRad51 significantly increased the expression of epithelial markers at an early stage of reprogramming compared with control cells. Phosphorylated histone H2AX (${\gamma}H2AX$), which initiates the DNA double-strand break repair system, was highly accumulated in reprogramming intermediates upon co-expression of Rad51. This study identified a novel role of Rad51 in enhancing the reprogramming efficiency, possibly by facilitating mesenchymal-to-epithelial transition and by regulating a DNA damage repair pathway during the early phase of the reprogramming process.

• Journal of Nutrition and Health
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• v.30 no.8
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• pp.987-994
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• 1997

To investigate the effects of n-3 fatty acids on breast cancer, MDA-MB231 human breast cancer cells were cultured in the presence of $\alpha$-linolenic (LNA), eicosapentaenoic(EPA), and docosahexaenoic acid (DHA) at a concentration of 0.5$\mu\textrm{g}$/ml in serum -free IMM medium. Cell growth was monitored and thiobarbituric acid reactive substances (TBARS), $\alpha$-tocopherol contents, and oncogene expression were measured. To compare the effects of n-3 fatty acids with other types of fatty acid, steraic (STA), olieic(OA). linoleic acid(LA) were used. After one day , cell growth was retarded most highly when DHA was in the medium. Cellular TBARS level measured after three days of culture was the highest with DHA in the medium and was also increased by LNA and EPA, compared with STA, OA and LA. Alpha-tocoopherol contents of cells were decreased by DHA but only modestly. There was non significant difference in $\alpha$-tocopherol contents in cells cultured in the presence of the other fatty acids. northern blot hybridization carried out with cells cultured during 24 hours showed that levels of erbB-2 mRNA were not altered by six different fatty acids in the medium but those of c-myc were transiently decreased in the early period by both n-6 and n-3 polyunsaturated fatty acids. The level of tumor suppressor gen p53 mRNA , however, was increased by DHA with time. It is concluded that the cytotoxicity of lipid peroxide and increased expression of tumor suppressor gene p53 are at least partly responsible for the inhibitory effect of DHA on growth of breast cancer cells.

• Journal of Physiology & Pathology in Korean Medicine
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• v.22 no.2
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• pp.377-384
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• 2008

The root of Vitis labrusca, is used as a source of health promoting drug in Korean traditional medicine. It has been reported that root of Vitis labrusca has antioxidant, anti lipid peroxidation and anti-reactive nitrogen species (RNS) activities. The aim of this study was to elucidate the molecular changes of apoptotic signaling pathways in phorbol 12-myristate 13 acetate (PMA)-induced human hepatocellular carcinoma cell line (Hep G2). The root of Vitis labrusca, ethanol extract (RVLEE) was tested for cell viability on Hep G2 cell using the MTT assay. RVLEE exhibited weak cytotoxic activity. However, treatment of Hep G2 cells with RVLEE suppressed PMA-induced cell proliferation. Also, dramatic changes of cell death signals in cellular molecules such as Chk2/Cds1, CIDE-B, CLIMP-63, Bax, Bcl-xL, C-myc, Bcl-2, Bric-5, NIP-3, TRAF2 and BAR but not CIDE-B and DR4. Futhermore, our results showed that the treatment of Hep G2 cells with 25 and $50\; {\mu}g/ml$ of RVLEE suppressed PMA-induced COX-2 gene activity. These data suggest that RVLEE have inhibitory effect of cell proliferation, induction of apoptosis and, thus, may offer therapeutic potential in Hep G2.

• Biomolecules & Therapeutics
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• v.20 no.6
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• pp.513-519
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• 2012

Although the immense efforts have been made for cancer prevention, early diagnosis, and treatment, cancer morbidity and mortality has not been decreased during last forty years. Especially, lung cancer is top-ranked in cancer-associated human death. Therefore, effective strategy is strongly required for the management of lung cancer. In the present study, we found that novel daphnane diterpenoids, yuanhualine (YL), yuanhuahine (YH) and yuanhuagine (YG) isolated from the flower of Daphne genkwa (Thymelaeaceae), exhibited potent anti-proliferative activities against human lung A549 cells with the $IC_{50}$ values of 7.0, 15.2 and 24.7 nM, respectively. Flow cytometric analysis revealed that the daphnane diterpenoids induced cell-cycle arrest in the G0/G1 as well as G2/M phase in A549 cells. The cell-cycle arrests were well correlated with the expression of checkpoint proteins including the up-regulation of cyclin-dependent kinase inhibitor p21 and p53 and down-regulation of cyclin A, cyclin B1, cyclin E, cyclin dependent kinase 4, cdc2, phosphorylation of Rb and cMyc expression. In the analysis of signal transduction molecules, the daphnane diterpenoids suppressed the activation of Akt, STAT3 and Src in human lung cancer cells. The daphnane diterpenoids also exerted the potent anti-proliferative activity against anticancer-drug resistant cancer cells including gemcitabine-resistant A549, gefitinib-, erlotinib-resistant H292 cells. Synergistic effects in the growth inhibition were also observed when yuanhualine was combined with gemcitabine, gefitinib or erlotinib in A549 cells. Taken together, these findings suggest that the novel daphnane diterpenoids might provide lead candidates for the development of therapeutic agents for human lung cancers.

• Biotechnology and Bioprocess Engineering:BBE
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• v.11 no.1
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• pp.7-12
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• 2006

Telomerase activation is detected in most cancerous cells; hence, telomerase is a highly selective target for cancer therapy, which plays an important role in the apoptotic process. We have previously reported that the ginseng saponin metabolite, Compound K (20-O-D-glucopyranosyl-20(S)-protopanaxadiol, IH901), inhibits cell proliferation by inducing apoptosis and cell cycle arrest at the $G_1$ phase. The present study investigated the regulation of telomerase activity in Compound K treated U937 cells. Compound K treatment caused a reduction in telomerase activity and down-regulated the human telomerase reverse transcriptase (hTERT) gene, resulting in the decreased expressions of its protein, and of the c-Myc and Spl proteins (transcription factors of hTERT). These results indicate that the anticancer activity of Compound K could be mediated by inhibition of the telomerase activity.

• The Journal of Korean Medicine
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• v.23 no.1
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• pp.24-36
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• 2002

Objectives: The chemotherapeutic potential of Gagamgilgyung-tang for the treatment of human lung cancer, the antitumorigenic effects of Gagamgilgyung-tang on the proliferation and apoptosis of human lung cancer cell line A427 were investigated using molecular biological approaches, Methods: To determine Gagamgilgyung-tang concentrations which do not evoke cytotoxic damage to the cell line, cell viability was examined by MTT assay. To prove Gagamgilgyung-tang's antitumorigenic potential to human lung cancer, [3H]thymidine incorporation assay, trypan blue exclusion and Cpp32 protease activity assays and quantitative RT-PCR analysis were examined. Results: While A427 cells treated with $0.1-2.0{\mu\textrm{g}}/ml$ of Gagamgilgyung-tang showed no recognizable effect, marked reductions of cell viability were detected at concentrations over $5.0{\;}\mu\textrm{g}/ml$. DNA replication of A427 cells was inhibited by Gagamgilgyung-tang in a dose-dependent manner and Gagamgilgyung-tang induced the G1 cell cycle arrest through inhibition of DNA replication. Gagamgilgyung-tang triggered apoptotic cell death of A427 and enhanced the apoptotic sensitivity of the cells that were injured by a DNA damage-inducing chemotherapeutic drug etoposide. Gagamgilgyung-tang induces expression of growth-inhibiting genes such as p53 and p21/Wafl whereas it inhibited expression of growth-promoting genes such as c-Myc and Cyclin D1. Expression of a representative apoptosis-inducing gene Bax was also found to be induced by Gagamgilgyung-tang while apoptosis-suppressing Bcl-2 expression was not changed. Conclusions: Gagamgilgyung-tang could suppress the abnormal growth of tumor cells by suppressing the survival of genetically altered cells via induction of apoptosis. This study suggests that Gagamgilgyung-tang might have an antitumorigenic potential to human lung cancer cells, which might be associated with its growth-inhibiting and apoptosis-inducing properties.