• 생명과학회지
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• 제28권9호
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• pp.1016-1021
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• 2018

C. difficile 톡신A에 의한 대장상피세포 자살과정은 위막성대장염(Pseudomembranous colitis)의 주요 원인으로 고려되고 있다. 톡신A는 활성산소 를 증가시켜 세포자살 신호를 유도한다. 또한 톡신A는 미세섬유나 미세소관과 같은 세포골격계 형성을 저해함으로써 자살을 유도한다고 알려져 있다. 하지만 톡신A가 야기하는 소화기 상피세포 자살경로는 아직 불분명하다. 본 연구에서는 소화관 상피세포의 성장과 분화 그리고 기능에 중요하다고 알려져 온 Wnt 신호경로에 대한 톡신A의 영향을 확인해보았다. 이를 위해 비암화-인간대장세포주(NCM460)에 톡신A를 처치하고 Wnt 신호 분자들의 변화를 추적하였다. 또한 톡신A를 주입한 생쥐의 회장 상피세포 속 Wnt 신호경로 변화도 평가하였다. 인간 대장상피세포에서 톡신A는 Wnt 경로의 핵심 신호분자인 ${\beta}$-catenin 단백질의 양을 빠르게 감소시켰다. 이 현상은 생쥐 회장 상피세포에서도 동일하게 확인되었다. 연구자 등은 톡신A가 $GSK3{\beta}$ 활성형 인산화(Thr390)를 증가시킴도 확인하였다. 이는 톡신A가 $GSK3{\beta}$의 활성을 높여서 ${\beta}$-catenin의 인산화시키고 이를 통해 단백질 분해 과정이 촉진되었음을 보여준다. 이 결과들을 종합하면, 톡신A에 의한 소화관 상피세포 자살과정이 상피세포의 성장과 자살을 조절하는 Wnt 신호경로 차단과 밀접하게 연관되어 있음을 보여준다.

• Biomolecules & Therapeutics
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• 제17권4호
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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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• 제9권4호
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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.

• 한국식품영양과학회지
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• 제35권5호
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• pp.516-523
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• 2006

차가버섯(Inonotus obliquus)은 한랭한 삼림지대에서 자라는 자작나무에 자생하는 버섯으로, 항종양 및 항돌연변이 활성이 있는 것으로 보고되고 있으나, 차가버섯의 항암기전에 대해 밝혀진 바가 없어, 본 연구에서는 인체의 대장암에서 유래한 HT-29 세포를 사용하여 차가버섯 물추출물의 대장암세포 증식 억제기전을 밝히고자 하였다. 차가버섯을 열수추출하여 냉동 건조하여 얻은 물추출물을 HT-29 세포 배양액에 여러 농도($0{\sim}100{\mu}g/mL$)로 첨가하여 세포의 증식에 미치는 영향을 조사하였다. 세포의 증식은 차가버섯 추출물 농도가 증가할수록 현저히 감소하였다. 차가버섯 물추출물 처리 농도에 비례하여 세포의 DNA합성은 감소하였고, apoptotic cell의 수는 현저히 증가하였다. Apoptosis의 주요한 조절 인자인 Bcl-2 family 단백질 수준은 차가버섯에 의해 변화하지 않았으나, cleaved caspase-8, -9, -3의 단백질 수준은 차가버섯에 의해 증가하였다. Caspase-8, -9, -3의 활성도 모두 차가버섯에 의해 유의적으로 증가하였다. Caspase-3의 표적 단백질로 세포의 생존에 결정적인 역할을 하는 PARP단백질의 분해도 차가버섯에 의해 현저히 증가하였다. 이 결과로부터 차가버섯 물추출물이 DNA합성을 억제하고 apoptosis를 유도하여 대장암 세포의 증식을 억제하고, caspase 경로의 활성을 증가하므로써 apoptosis를 유도한다는 결론을 내릴 수 있다. 또한 이 결과는 차가버섯 물추출물을 대장암의 예방이나 치료에 사용할 수 있는 가능성을 제시한다.

• Asian Pacific Journal of Cancer Prevention
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• 제15권16호
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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.

• 한국식품영양과학회지
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• 제46권2호
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• pp.161-168
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• 2017

본 연구에서는 산화적 스트레스로 유도한 시신경 세포사멸에 대한 차조기 물 추출물(PFE)의 효과를 확인하였다. Staurosporine으로 분화된 ssdRGC-5 세포에 buthionine과 glutamate(B/G)로 산화적 스트레스를 유도하였으며, LDH release assay, MTT reduction assay를 통하여 PFE가 농도 의존적으로 B/G에 의한 세포사멸을 억제함을 관찰하였다. 세포사멸의 기전을 연구하기 위해 caspase 활성, 세포 내 ROS 생성량, 세포고사 관련 단백질 발현을 관찰한 결과, B/G에 의해 증가한 ROS 생성량, caspase 활성을 PFE가 억제하였고, 세포질로 방출된 cytochrome c와 미토콘드리아로 이동한 Bax도 감소함을 확인하였다. 이상의 결과로부터 차조기는 산화적 스트레스로 유도된 시신경 세포사멸 과정에서 항산화 효과와 미토콘드리아성 세포사멸을 완화함으로써 세포 보호 작용을 나타냄을 확인하였다.

• Tuberculosis and Respiratory Diseases
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• 제75권1호
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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.

• 생명과학회지
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• 제14권5호
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• pp.800-808
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• 2004

Resveratrol은 포도와 같은 식물에서 각종 감염균으로부터 자신의 몸을 보호하기 위하여 생성되는 물질인 phytoalexin의 일종으로 강력한 항산화작용, 암예방 효과 및 항암 작용을 포함한 각종 약리작용을 가진 것으로 보고되어져 오고 있다. 본 연구에서는 resveratrol의 항암작용 기전해석을 위하여 A549 인체폐암세포의 종식에 미치는 resverakol의 영향을 조사하였다. A549 세포의 생존율은 resveratrol의 처리시간 증가에 따라 강력하게 억제되었으며, 이는 암세포의 다양한 형태변형을 동반한 세포주기 C2/M arrest 및 염색질 응축 현상을 동반한 apoptosis 유발에 의한 것임을 알 수 있었다. Resveratrol 처리에 의한 apoptosis 유발은 Bcl-2의 발현변화 없이 Bcl-$X_L$의 발현 감소에 따른 상대적인 Bax의 발현 증가와 Sp-1, PCNA 및 $\beta$-catenin 등과 같은 단백질의 분해 현상과 연관성이 있었다 또한 resveratrol에 의한 A549세포 의 증식억제는 Cdk inhibitor p21의 발현 증가에 따른 Cdks 의 kinase 활성 저하 및 COX-2의 선택적 저해에 따른 PGE2 생성 저하와 관련이 있었다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권8호
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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.

• 대한한의학방제학회지
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• 제25권1호
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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.