• Journal of Life Science
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• v.28 no.9
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• pp.1016-1021
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• 2018

Clostridium difficile toxin A causes pseudomembranous colitis. The pathogenesis of toxin A-induced colonic inflammation includes toxin A-dependent epithelial cell apoptosis, resulting in the loss of barrier function provided by epithelial cells against luminal pathogens. Toxin A-dependent epithelial cell apoptosis has been linked to toxin A-induced production of reaction oxygen species and subsequent p38MAPK activation; $p21^{CIP1/WAF1}$ upregulation-dependent cell cycle arrest; cytoskeletal disaggregation; and/or the induction of Fas ligand on epithelial cells. However, the molecular mechanisms underlying toxin A-induced apoptosis remain poorly understood. This study tested whether toxin A could block the Wnt signaling pathway, which is involved in gut epithelial cell proliferation, differentiation and antiapoptotic progression. Toxin A treatment of nontransformed human colonocytes (NCM460) rapidly reduced ${\beta}$-catenin protein, an essential component of the Wnt signaling pathway. Exposure of mouse ileum to toxin A also significantly reduced ${\beta}$-catenin protein levels. MG132 inhibition of proteasome-dependent protein degradation resulted in the recovery of toxin A-mediated reduction of ${\beta}$-catenin, indicating that toxin A may activate intracellular processes, such as $GSK3{\beta}$, to promote degradation of ${\beta}$-catenin. Immunoblot analysis showed that toxin A increased active phosphorylation of $GSK3{\beta}$. Because the Wnt signaling pathway is essential for gut epithelial cell proliferation and anti-apoptotic processes, our results suggest that toxin A-mediated inhibition of the Wnt signaling pathway may be required for maximal toxin A-induced apoptosis of gut epithelial cells.

• Biomolecules & Therapeutics
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• v.17 no.4
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• pp.403-411
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• 2009

Thiacremonone, the main component isolated from heated garlic (Allium sativum L.), is interested for using as a cancer preventive or therapeutic agent since garlic has been known to be useful plant in the treatment of cancers. Nuclear factor kappaB (NF-${\kappa}B$) is constitutively activated in the prostate cancer and activation of NF-${\kappa}B$ is implicated in drug resistance in cancer cells. Docetaxel, a semisynthetic analog of paclitaxel, is an antineoplastic drug widely used for advanced various cancer. In previous studies, we found that thiacremonone inhibited activation of NF-${\kappa}B$ in cancer cells and marcrophages. In the present study, we investigated whether thiacremonone could increase susceptibility of prostate cancer cells (PC-3 and DU145) to docetaxel via inactivation of NF-${\kappa}B$. We found that the combination treatment of thiacremonone (50 ${\mu}g$/ml) with docetaxel (5 nM) was more effective in the inhibition of prostate cancer cell growth and induction of apoptosis accompanied with the significant inhibition of NF-${\kappa}B$ activity than those by the treatment of thiacremonone or docetaxel alone. It was also found that NF-${\kappa}B$ target gene expression of Bax, caspase-3 and caspase-9 was much more significantly enhanced, but the expression of Bcl-2 was also much more significantly inhibited by the combination treatment. These results indicate that thiacremonone inhibits NF-${\kappa}B$, and enhances the susceptibility of prostate cancer cells to docetaxel. Thus, thiacremonone could be useful as an adjuvant anti-cancer agent.

• The Korean Journal of Physiology and Pharmacology
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• v.9 no.4
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• pp.239-246
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• 2005

In the central nervous system, nitric oxide (NO) is associated with many pathological diseases such as brain ischemia, neurodegeneration and inflammation. The epigallocatechin gallate (EGCG), a major compound of green tea, is recognized as protective substance against neuronal diseases. This study is aimed to investigate the effect of EGCG on NO-induced cell death in PC12 cells. Administration of sodium nitroprusside (SNP), a NO donor, decreased cell viability in a dose- and time-dependent manner and induced genomic DNA fragmentation with cell shrinkage and chromatin condensation. EGCG diminished the decrement of cell viability and the formation of apoptotic morphologenic changes as well as DNA fragmentation by SNP. EGCG played as an antioxidant that attenuated the production of reactive oxygen species (ROS) by SNP. The cells treated with SNP showed downregulation of Bcl-2, but upregulation of Bax. EGCG ameliorated the altered expression of Bcl-2 and Bax by SNP. The release of cytochrome c from mitochondria into cytosol and expression of voltage -dependent anion channel (VDAC)1, a cytochrome c releasing channel in mitochondria, were increased in SNP-treated cells, whereas were attenuated by EGCG. The enhancement of caspase-9, preceding mitochondria-dependent pathway, caspase-8 and death receptor-dependent pathway, as well as caspase-3 activities were suppressed by EGCG. SNP upragulated Fas and Fas-L, which are death receptor assembly, whereas EGCG ameliorated the expression of Fas enhanced by SNP. These results demonstrated that EGCG has a protective effect against SNP-induced apoptosis in PC12 cells, through scavenging ROS and regulating the mitocondria- and death receptor-mediated signal pathway. The present study suggest that EGCG might be a natural neuroprotective substance.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.5
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• pp.516-523
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• 2006

The mushroom Inonotus obliquue (IO) has been traditionally used for the treatment of gastrointestinal cancer in Russia, Poland, and most of Baltic countries. To explore the possibility that IO has chemoprevention effects, we examined whether or not the aqueous extract of IO inhibits HT-29 cell growth and investigated tile mechanism for this effect. Cells were incubated in the presence of increasing concentrations of the aqueous extract of IO. The extract substantially inhibited the viable HT-29 cell number in a dose-dependent manner and inhibited 5-bromo-2'-deoxyuridine incorporation into DNA of HT-29 cells. Annexin-V staining followed by flow cytometry revealed that the extract induced apoptosis of HT-29 cells in a dose-dependent manner. Western blot analysis of total cell lysates revealed that the extract induced cleavage of caspase-8, -9 and -3 and poly (ADP-ribose) polymerase, but did not affect the protein levels of Bax and Bcl-2. In addition, the extract dose-dependently increased the activity of caspase-8, -9 and -3. We have demonstrated that the aqueous extract of IO inhibits cell proliferation and induces apoptosis in HT-29 cells, which may be mediated by its ability to activate the caspase pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.16
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• pp.6737-6743
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• 2014

It is reported that sinomenine (SIN) and 5-fluorouracil (5-FU) both are effective for colon cancer, but their cooperative suppressive effects and toxicity remain to be clarified in detail. This study aimed to determine suppressive effects and toxicity of sinomenine (SIN) plus 5-fluorouracil (5-FU) on LoVo colon carcinoma cells in vitro and in vivo. CCK-8, Hoechst 33258 staining and an annexin V-FITC/PI apoptosis kit were used to detect suppressive effects. Western blotting was applied to investigate the essential mechanism underlying SIN and 5-FU-induced apoptosis. SIN or 5-FU or both were injected into nude mice, and then suppressive effects and side effects were observed. SIN plus 5-FU apparently inhibited the proliferation of LoVo cells and induced apoptosis. Moreover the united effects were stronger than individually (p<0.05). The results of annexin V-FITC/PI staining and Hoechst 33258 staining showed that the percentage of apoptotic cells induced by SIN and 5-FU combined or alone was significantly higher than the control group (p<0.05). Expression of Bax and Bcl-2 was up-regulated and down-regulated respectively. SIN or 5-FU significantly inhibited effects on the volume of tumour xenografts and their combined suppressive effects were stronger (p<0.05). No obvious side effects were observed. It was apparent that the united effects of SIN and 5-FU on the growth of colorectal carcinoma LoVo cells in vitro and in vivo were superior to those using them individually, and it did not markedly increase the side effects of chemotherapy.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.2
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• pp.161-168
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• 2017

In this study, we examined the effect of Perilla frutescens extract (PFE) on oxidative stress-induced cell death in RGC-5 cell lines. Staurosporine-differentiated RGC-5 (ssdRGC-5) cells obtained by treating RGC-5 cells with $1{\mu}M$ staurosporine were incubated with PFE for 30 min and then exposed to buthionine sulfoximine plus glutamate (B/G) for 20 h. Cell death was detected using lactate dehydrogenase release assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide reduction assay. To investigate the mechanism underlying cell death, we determined caspase-3 activity, level of reactive oxygen species (ROS) formation, and expression levels of cytoplasmic cytochrome c and mitochondrial Bax. Treatment of ssdRGC-5 cells with B/G increased intracellular ROS and induced apoptosis with increasing caspase-3 activity. PFE rescued ssdRGC-5 cells from oxidative stress-induced cell death by inhibiting intracellular ROS production and caspase-3 activation and regulating apoptosis-related proteins such as cytochrome c and Bax. These findings suggest that PFE may have a beneficial neuroprotective effect against oxidative stress-induced apoptotic death in ssdRGC-5 cells.

• Tuberculosis and Respiratory Diseases
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• v.75 no.1
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• pp.9-17
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• 2013

Background: In cancer cells, autophagy is generally induced as a pro-survival mechanism in response to treatment-associated genotoxic and metabolic stress. Thus, concurrent autophagy inhibition can be expected to have a synergistic effect with chemotherapy on cancer cell death. Monensin, a polyether antibiotic, is known as an autophagy inhibitor, which interferes with the fusion of autophagosome and lysosome. There have been a few reports of its effect in combination with anticancer drugs. We performed this study to investigate whether erlotinib, an epidermal growth factor receptor inhibitor, or rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, is effective in combination therapy with monensin in non-small cell lung cancer cells. Methods: NCI-H1299 cells were treated with rapamycin or erlotinib, with or without monensin pretreatment, and then subjected to growth inhibition assay, apoptosis analysis by flow cytometry, and cell cycle analysis on the basis of the DNA contents histogram. Finally, a Western blot analysis was done to examine the changes of proteins related to apoptosis and cell cycle control. Results: Monensin synergistically increases growth inhibition and apoptosis induced by rapamycin or erlotinib. The number of cells in the sub-$G_1$ phase increases noticeably after the combination treatment. Increase of proapoptotic proteins, including bax, cleaved caspase 3, and cleaved poly(ADP-ribose) polymerase, and decrease of anti-apoptotic proteins, bcl-2 and bcl-xL, are augmented by the combination treatment with monensin. The promoters of cell cycle progression, notch3 and skp2, decrease and p21, a cyclin-dependent kinase inhibitor, accumulates within the cell during this process. Conclusion: Our findings suggest that concurrent autophagy inhibition could have a role in lung cancer treatment.

• Journal of Life Science
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• v.14 no.5
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• pp.800-808
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• 2004

Resveratrol, a phytoalexin found at high levels in grapes and in grape products such as red wine, has been reported to possess a wide range of biological and pharmacological activities including antioxident, anti-inflammatory, anti-mutagenic, and anti-carcinogenic effects. According to recent studies, this compound is an effective inhibitor of cell growth in general, triggers partial arrest of the cell cycle and induce apoptosis. In this study, the anti-proliferative effects of resveratrol in A549 human lung carcinoma cells were investigated. It is shown that resveratrol induced the growth inhibition in a time-dependent manner and morphological changes of A549 cells, which were associated with induction of S phase arrest of the cell cycle and apoptotic cell death. The Bcl-$X_L$levels were markedly down-regulated in resveratrol treated cells, however, Bax and Bcl-2 were remained unchanged. Resveratrol treatment induced the proteolytic degradation of Sp-l and proliferating cell nuclear antigen protein, and inhibited the expression of $\beta$-catenin protein. Resveratrol treatment also induced a marked up-regulation of cyclin-dependent kinase (Cdk) inhibitor p21 and inhibited the kinase activities of Cdk2 and Cdk4. In addition, resveratrol treatment inhibited the levels of cyclooxygenase (COX)-2 mRNA and protein, and the release of prostagladin E2 without alteration of COX-1 expression. Taken together, these findings suggest that resveratrol may be a potential chemotherapeutic agent for the control of human lung carcinorma cells.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.8
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• pp.3301-3306
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• 2015

Nucleolin (C23) is an important anti-apoptotic protein that is ubiquitously expressed in exponentially growing eukaryotic cells. In order to understand the impact of C23 in radiation therapy, we attempted to investigate the relationship of C23 expression with the radiosensitivity of human non-small cell lung cancer (NSCLC) cells. We investigated the role of C23 in activating the catalytic subunit of DNA-dependent protein kinase (DNA-PKcs), which is a critical protein for DNA double-strand breaks (DSBs) repair. As a result, we found that the expression of C23 was negatively correlated with the radiosensitivity of NSCLC cell lines. In vitro clonogenic survival assays revealed that C23 knockdown increased the radiosensitivity of a human lung adenocarcinoma cell line, potentially through the promotion of radiation-induced apoptosis and adjusting the cell cycle to a more radiosensitive stage. Immunofluorescence data revealed an increasing quantity of ${gamma}$-H2AX foci and decreasing radiation-induced DNA damage repair following knockdown of C23. To further clarify the mechanism of C23 in DNA DSBs repair, we detected the expression of DNA-PKcs and C23 proteins in NSCLC cell lines. C23 might participate in DNA DSBs repair for the reason that the expression of DNA-PKcs decreased at 30, 60, 120 and 360 minutes after irradiation in C23 knockdown cells. Especially, the activity of DNA-PKcs phosphorylation sites at the S2056 and T2609 was significantly suppressed. Therefore we concluded that C23 knockdown can inhibit DNA-PKcs phosphorylation activity at the S2056 and T2609 sites, thus reducing the radiation damage repair and increasing the radiosensitivity of NSCLC cells. Taken together, the inhibition of C23 expression was shown to increase the radiosensitivity of NSCLC cells, as implied by the relevance to the notably decreased DNA-PKcs phosphorylation activity at the S2056 and T2609 clusters. Further research on targeted C23 treatment may promote effectiveness of radiotherapy and provide new targets for NSCLC patients.

• Herbal Formula Science
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• v.25 no.1
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• pp.51-68
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• 2017

Objectives : Oxidative stress due to excessive accumulation of reactive oxygen species (ROS) is one of the risk factors for the development of several chronic diseases, including neurodegenerative diseases. Methods : In the present study, we investigated the protective effects of cheongnoemyeongsin-hwan (CNMSH) against oxidative stress‑induced cellular damage and elucidated the underlying mechanisms in neuronal-derived SH-SY5Y cells. Results : Our results revealed that treatment with CNMSH prior to hydrogen peroxide (H2O2) exposure significantly increased the SH-SY5Y cell viability, indicating that the exposure of the SH-SY5Y cells to CNMSH conferred a protective effect against oxidative stress. CNMSH also effectively attenuated H2O2‑induced comet tail formation, and decreased the phosphorylation levels of the histone ${\gamma}H2AX$, as well as the number of apoptotic bodies and Annexin V‑positive cells. In addition, CNMSH exhibited scavenging activity against intracellular ROS generation and restored the mitochondria membrane potential (MMP) loss that were induced by H2O2, suggesting that CNMSH prevents H2O2‑induced DNA damage and cell apoptosis. Moreover, H2O2 enhanced the cleavage of caspase-3 and degradation of poly (ADP-ribose)-polymerase, a typical substrate protein of activated caspase-3, as well as DNA fragmentation; however, these events were almost totally reversed by pretreatment with CNMSH. Furthermore, CNMSH increased the levels of heme oxygenase-1 (HO-1), which is a potent antioxidant enzyme, associated with the induction of nuclear factor-erythroid 2-related factor 2 (Nrf2). According to our data, CNMSH is able to protect SH-SY5Y cells from H2O2-induced apoptosis throughout blocking cellular damage related to oxidative stress through a mechanism that would affect ROS elimination and activating Nrf2/HO-1 signaling pathway. Conclusions : Therefore, we believed that CNMSH may potentially serve as an agent for the treatment and prevention of neurodegenerative diseases caused by oxidative stress.