• 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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• 제26권6호
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• pp.584-590
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• 2018

Osteoporosis development is closely associated with oxidative stress and reactive oxygen species (ROS). Taurine has potential antioxidant effects, but its role in osteoblasts is not clearly understood. The aim of this study was to determine the protective effects and mechanisms of actions of taurine on hydrogen peroxide ($H_2O_2$)-induced oxidative stress in osteoblast cells. UMR-106 cells were treated with taurine prior to $H_2O_2$ exposure. After treatment, cell viability, apoptosis, intracellular ROS production, malondialdehyde content, and alkaline phosphate (ALP) activity were measured. We also investigated the protein levels of ${\beta}-catenin$, ERK, CHOP and NF-E2-related factor 2 (Nrf2) along with the mRNA levels of Nrf2 downstream antioxidants. The results showed that pretreatment of taurine could reverse the inhibition of cell viability and suppress the induced apoptosis in a dose-dependent manner: taurine significantly reduced $H_2O_2$-induced oxidative damage and expression of CHOP, while it induced protein expression of Nrf2 and ${\beta}-catenin$ and activated ERK phosphorylation. DKK1, a Wnt/${\beta}-catenin$ signaling inhibitor, significantly suppressed the taurine-induced Nrf2 signaling pathway and increased CHOP. Activation of ERK signaling mediated by taurine in the presence of $H_2O_2$ was significantly inhibited by DKK1. These data demonstrated that taurine protects osteoblast cells against oxidative damage via Wnt/${\beta}-catenin$-mediated activation of the ERK signaling pathway.

• Asian Pacific Journal of Cancer Prevention
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• 제14권5호
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• pp.3093-3099
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• 2013

Background: Phytic acid (PA) is a polyphosphorylated carbohydrate that can be found in high amounts in most cereals, legumes, nut oil, seeds and soy beans. It has been suggested to play a significant role in inhibition of colorectal cancer. This study was conducted to investigate expression changes of ${\beta}$-catenin and cyclooxygenase-2 (COX-2) and cell proliferation in the adenoma-carcinoma sequence after treatment with rice bran PA by immunocytochemistry. Materials and Methods: Seventy-two male Sprague-Dawley rats were divided into 6 equal groups with 12 rats in each group. For cancer induction two intraperitoneal injections of azoxymethane (AOM) were given at 15 mg/kg bodyweight over a 2-weeks period. During the post initiation phase, two different concentrations of PA, 0.2% (w/v) and 0.5% (w/v) were administered in the diet. Results: Results of ${\beta}$-catenin, COX-2 expressions and cell proliferation of Ki-67 showed a significant contribution in colonic cancer progression. For ${\beta}$-catenin and COX-2 expression, there was a significant difference between groups at p<0.05. With Ki-67, there was a statistically significant lowering the proliferating index as compared to AOM alone (p<0.05). A significant positive correlation (p=0.01) was noted between COX-2 expression and proliferation. Total ${\beta}$-catenin also demonstrated a significant positive linear relationship with total COX-2 (p=0.044). Conclusions: This study indicated potential value of PA extracted from rice bran in reducing colonic cancer risk in rats.

• Asian Pacific Journal of Cancer Prevention
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• 제17권7호
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• pp.3551-3558
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• 2016

Colorectal cancer (CRC) is a major cause of morbidity and mortality throughout the world, with chronic inflammation and diet as major causes in its development. Chemopreventive effects of natural dietary products have been the focus of studies for prevention over the past decade. This study was conducted to determine the effects of unpolished Thai rice during precancerous stage through the involvement of ${\beta}$-catenin, cyclooxygenase-2 (COX-2) expression and inflammatory cytokines focusing on azoxymethane (AOM)-induced aberrant crypt foci (ACF)-related to CRC. Male Sprague Dawley rats received two injections of AOM (15 mg/kg body weight) at weeks 4 and 5 while rats were treated with 20% or 70% unpolished Thai rice. The rats were sacrificed at week 38 and the colons removed for aberrant crypt foci (ACF) identification. Histopathologic changes, immunohistochemical analysis of ${\beta}$-catenin and COX-2 expression, and cytokine expression of proinflammatory and anti-inflammatory markers were determined. The administration of unpolished Thai rice significantly and dose dependently decreased the total number of ACF and the percentages of ACF with high-grade dysplasia. Interestingly, unpolished Thai rice suppressed the expression of ${\beta}$-catenin and COX-2. In addition, it also altered proinflammatory (IL-6 and IFN-${\gamma}$) and anti-inflammatory (IL- 10) markers. The results suggested that unpolished Thai rice may provide a promising dietary intake for prevention during precancerous stage of CRC development, through the involvement of ${\beta}$-catenin and COX-2 expression, and also modulate inflammatory cytokines-related to CRC.

• BMB Reports
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• 제50권1호
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• pp.1-2
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• 2017

Acquiring a selective growth advantage by breaking the proliferation barrier established by gatekeeper genes is a centrally important event in tumor formation. Removal of the mammalian Hippo kinase Mst1 and Mst2 in hepatocytes leads to rapid hepatocellular carcinoma (HCC) formation, indicating that the Hippo signaling pathway is a critical gatekeeper that restrains abnormal growth in hepatocytes. By rigorous genetic approaches, we identified an interacting network of the Hippo, Wnt/${\beta}$-catenin and Notch signaling pathways that control organ size and HCC development. We found that in hepatocytes, the loss of Mst1/2 leads to the activation of Notch signaling, which forms a positive feedback loop with Yap/Taz (transcription factors controlled by Mst1/2). This positive feedback loop results in severe liver enlargement and rapid HCC formation. Blocking the Yap/Taz-Notch positive feedback loop by Notch inhibition in vivo significantly reduced the Yap/Taz activities, hepatocyte proliferation and tumor formation. Furthermore, we uncovered a surprising inhibitory role of Wnt/${\beta}$-catenin signaling to Yap/Taz activities, which are important in tumor initiation. Genetic removal of ${\beta}$-catenin in the liver of the Mst1/2 mutants significantly accelerates tumoriogenesis. Therefore, Wnt/${\beta}$-catenin signaling, known for its oncogenic property, exerts an unexpected function in restricting Yap/Taz and Notch activities in HCC initiation. The molecular interplay between the three signaling pathways identified in our study provides new insights in developing novel therapeutic strategies to treat liver tumors.

• 한국식품저장유통학회지
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• 제24권4호
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• pp.524-528
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• 2017

Ricinus communis, belongs to the family Euphorbiaceae, has been known as medicinal plants for treatment of inflammation, tumors, antidiabetic, hepatoprotective and laxative. Compared to many pharmacological studies, the effect of R. communis extract on regulating adipogenesis as therapeutic drug for treating obesity has not been reported. R. communis extract (RCE) was investigated to determine its effects on the adipogenesis by monitoring the status of $Wnt/{\beta}-catenin$ signaling and factors involving the differentiation of adipocytes. The differentiation of 3T3-L1 cells monitored by Oil Red O staining was inhibited in concentration dependent manner by RCE. The luciferase activity of HEK 293-TOP cells containing pTOPFlash with Tcf4 response element-luciferase gene was increased approximately 2-folds by the treatment of RCE at concentrations of $100{\mu}g/mL$ compared to the control. Activation of the $Wnt/{\beta}-catenin$ pathway by RCE was further confirmed by immunocytochemical analysis which shows an increment of nuclear localization of ${\beta}-catenin$. In addition, safety of RCE was verified through performing neural stem cell morphology assay. Among the identified flavonoids in RCE, isoquercitrin was the most abundant. Therefore, these results indicate that the adipocyte differentiation was significantly reduced by isoquercitrin in R. communis. In this study, RCE suppresses the adipogenesis of 3T3-L1 cells via the activation of $Wnt/{\beta}-catenin$ signaling.

• 생약학회지
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• 제44권4호
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• pp.384-390
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• 2013

This study was conducted to evaluate the effect of wheat bran on the promotion of hair growth. When rat vibrissa follicles were treated with n-hexane fraction of wheat bran, the hair-fiber lengths of the vibrissa follicles significantly increased. Moreover, n-hexane fraction of wheat bran was found to significantly induce the telogen-anagen transition in C57BL/6 mice. The fraction increased the proliferation of immortalized vibrissa dermal papilla cells (DPCs) in a dose dependent manner. To elucidate the molecular mechanisms in relation to proliferation of DPCs by the fraction of wheat bran, we examined the expression of cell cycle proteins and wnt/${\beta}$-catenin signaling components. Western blot analysis revealed that the proliferation of DPC by n-hexane fraction of wheat bran was accompanied by increased the level of cyclin D1, cyclin E, phospho-CDK2 and phospho-pRB. In addition, the fraction of wheat bran increased the level of phospho(ser552)-${\beta}$-catenin, phospho(ser675)-${\beta}$-catenin and phospho(ser9)-GSK$3{\beta}$. These results suggest that the hair growing potential of wheat bran mediated by proliferation of DPCs via the regulation of cell cycle proteins and Wnt/${\beta}$-catenin signaling.

• 생약학회지
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• 제47권2호
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• pp.143-149
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• 2016

Grateloupia elliptica has been reported to have the proliferation effect of dermal papilla cells (DPCs), which play important roles in the regulation of hair cycle. In the present study, we examined in vitro and in vivo hair growth-promoting effect of Grateloupia elliptica. When isolated rat vibrissa follicles were treated with extract of G. elliptica, the hair-fiber lengths of the vibrissa follicles significantly increased. Furthermore, the G. elliptica extract accelerated the telogen-angen transition in C57BL/6 mice. To investigate the molecular mechanisms of the G. elliptica extract on the proliferation of DPCs, we examined the activation of $wnt/{\beta}$-catenin signaling which is known to regulate hair follicle development, differentiation and hair growth. The G. elliptica extract activated $wnt/{\beta}$-catenin signaling via the increase of ${\beta}$-catenin and phospho-$GSK3{\beta}$. In addition, the G. elliptica extract increased the level of cyclin E and CDK2, while the level of $p27^{kip1}$ was decreased. These results suggest that the the G. elliptica extract may induce hair growth by proliferation of DPCs via cell-cycle progression and the activation of $Wnt/{\beta}$-catenin signaling.

• Experimental and Molecular Medicine
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• 제50권11호
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• pp.12.1-12.12
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• 2018

Drugs targeting the epidermal growth factor receptor (EGFR), such as cetuximab and panitumumab, have been prescribed for metastatic colorectal cancer (CRC), but patients harboring KRAS mutations are insensitive to them and do not have an alternative drug to overcome the problem. The levels of ${\beta}$-catenin, EGFR, and RAS, especially mutant KRAS, are increased in CRC patient tissues due to mutations of adenomatous polyposis coli (APC), which occur in 90% of human CRCs. The increases in these proteins by APC loss synergistically promote tumorigenesis. Therefore, we tested KYA1797K, a recently identified small molecule that degrades both ${\beta}$-catenin and Ras via $GSK3{\beta}$ activation, and its capability to suppress the cetuximab resistance of KRAS-mutated CRC cells. KYA1797K suppressed the growth of tumor xenografts induced by CRC cells as well as tumor organoids derived from CRC patients having both APC and KRAS mutations. Lowering the levels of both ${\beta}$-catenin and RAS as well as EGFR via targeting the $Wnt/{\beta}$-catenin pathway is a therapeutic strategy for controlling CRC and other types of cancer with aberrantly activated the $Wnt/{\beta}$-catenin and EGFR-RAS pathways, including those with resistance to EGFR-targeting drugs attributed to KRAS mutations.

• Asian Pacific Journal of Cancer Prevention
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• 제15권3호
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• pp.1075-1079
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• 2014

MicroRNA expression is a research focus in studies of tumors. This article concentrates attention on potential links between tumors caused by mouse mammary tumor virus (MMTV) and human breast cancer, in order to provide theoretical basis for using mouse model to search for miRNA effects mediated by Wnt/beta-catenin signaling in human breast cancer. By analyzing interactions between miRNAs and the Wnt/beta-catenin signaling pathway in breast cancer, we hope to casts light on more biological functions of miRNAs in the process of tumor formation and growth and to explore their potential value in cancer diagnosis, prognosis and treatment. Our endeavor aimed at providing theoretical basis for finding safer, more effective methods for treatment of human breast cancer at the miRNA molecular level.