• Molecules and Cells
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• 제24권2호
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• pp.167-176
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• 2007

Peroxisome proliferator-activated receptor-gamma ($PPAR{\gamma}$) is expressed at very high levels in the gastrointestinal epithelium. Many of the functions of $PPAR{\gamma}$ in gastrointestinal epithelial cells have been elucidated in recent years, and a pattern is emerging which suggests that this receptor plays an important role in gastrointestinal physiology. There is also strong evidence that $PPAR{\gamma}$ is a colon cancer suppressor in pre-clinical rodent models of sporadic colon cancer, and there is considerable interest in exploitation of $PPAR{\gamma}$ agonists as prophylactic or chemopreventive agents in colon cancer. Studies in mice and in human colon cancer cell lines suggest several mechanisms that might account for the tumor suppressive effects of $PPAR{\gamma}$ agonists, although it is not in all cases clear whether these effects are altogether mediated by $PPAR{\gamma}$. Conversely, several reports suggest that $PPAR{\gamma}$ agonists may promote colon cancer under certain circumstances. This possibility warrants considerable attention since several million individuals with type II diabetes are currently taking $PPAR{\gamma}$ agonists. This review will focus on recent data related to four critical questions: what is the physiological function of $PPAR{\gamma}$ in gastrointestinal epithelial cells; how does $PPAR{\gamma}$ suppress colon carcinogenesis; is $PPAR{\gamma}$ a tumor promoter; and what is the future of $PPAR{\gamma}$ in colon cancer prevention?

• Parasites, Hosts and Diseases
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• 제33권4호
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• pp.357-364
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• 1995

이질아메바에 의한 장염 환자의 조직 또는 이질아메바를 실험적으로 감염시킨 동물의 조직 검사에서 호중구의 침윤이 특징적으로 관찰된다. 그러나 이와같은 호중구의 침윤을 설명할 수 있는 기전에 대한 연구는 매우 미흡하다. 따라서 본 연구자들은 아메바 감염 초기에 인체 대장상피 세포에서 interleukin-8(IL-8)이 유도되어 호중구 침윤과 같은 염증반응이 유발될 것이라는 가설을 설정하였다. 이를 위하여 인체 대장상피세포주인 HT-29에 이질아메바 영양형을 실험적으로 노출시킨 뒤 발현되는 IL-S mRNA를 역전사 중합효소법(reverse transcriptional polymerase chain reaction, RT-PCR)으로 검사함과 퐁시에 발현된 IL-8 mRNA를 인공적으로 합성시킨 표준 RNA와 RT-PCR법을 이용하여 정량하였다. 실험 결과 이질아메바 영양형에 노출된 30분 후 부터 IL-8 mRAN가 발현되기 시작하였다 그리고 그 발현 분자수는 노출 시간의 증가에 따라 계속 증가하여 3시간 대에는 $3.1{\;}{\times}{\;}10^7{\;}molecules/\mu\textrm{g}$ total RNA를 나타내었다. 동시에 IL-8 mRNA의 발현은 노출시킨 이질아메바 영양형의 수에 비례하였다. 즉 HT-29/아메바 영양형의 비율이 10:1인 경우 IL-8 mRNA의 발현 분자수는 $1.2{\;}{\times}{\;}10^7{\;}molecules/\mu\textrm{g}$ total RNA로 나타났다. 이와같은 IL-8 mRNA의 발현은 IL-8 단백질 분비로 이어짐을 ELISA 검사로 확인할 수 있었다. 한편 이질아메바 파쇄액(Iysate)도 대장상피세포군인 Caco-2에서 IL-8 mRNA발현을 유도하였다. 결론적으로 본 실험은 이질아메바 감염 초기에 대장상피세포로 부터 IL-8이 발현되며, 이에 의하여 염증반응이 촉발될 가능성이 있음을 시사해 준다.

• Biomolecules & Therapeutics
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• 제30권2호
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• pp.137-144
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• 2022

Radiation resistance represents an imperative obstacle in the treatment of patients with colorectal cancer, which remains difficult to overcome. Here, we explored the anti-proliferative and migration-inhibiting properties of the natural product shikonin on a radiation-resistant human colon carcinoma cell line (SNU-C5RR). Shikonin reduced the viability of these cells in a dose-dependent manner; 38 µM of shikonin was determined as the half-maximal inhibitory concentration. Shikonin induced apoptotic cell death, as demonstrated by increased apoptotic body formation and the number of TUNEL-positive cells. Moreover, shikonin enhanced mitochondrial membrane depolarization and Bax expression and also decreased Bcl-2 expression with translocation of cytochrome c from mitochondria into the cytosol. In addition, shikonin activated mitogen-activated protein kinases, and their specific inhibitors reduced the cytotoxic effects of shikonin. Additionally, shikonin decreased the migration of SNU-C5RR cells via the upregulation of E-cadherin and downregulation of N-cadherin. Taken together, these results suggest that shikonin induces mitochondria-mediated apoptosis and attenuates epithelial-mesenchymal transition in SNU-C5RR cells.

• Biomolecules & Therapeutics
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• 제18권4호
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• pp.402-410
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• 2010

Although the overproduction of prostaglandin $E_2$ ($PGE_2$) in intestinal epithelial cells has been considered to be highly correlated with the colorectal carcinogenesis, the precise mechanism of action remains poorly elucidated. Accumulating evidence suggests that the PGE receptor (EP)-mediated signal transduction pathway might play an important role in this process. In the present study, we investigated the mechanism of action underlying $PGE_2$-mediated cell proliferation and the effect of resveratrol on the proliferation of human colon cancer cells in terms of the modulating $PGE_2$-mediated signaling pathway. $PGE_2$ stimulated the proliferation of several human colon cancer cells and activated growth-stimulatory signal transduction, including Akt and ERK. $PGE_2$ also increased the phosphorylation of GSK-$3{\beta}$, the translocation of ${\beta}$-catenin into the nucleus, and the expressions of c-myc and cyclin D1. Resveratrol, a cancer chemopreventive phytochemical, however, inhibited $PGE_2$-induced growth stimulation and also suppressed $PGE_2$-mediated signal transduction, as well as ${\beta}$-catenin/T cell factor-mediated transcription in human colon cancer cells. These findings present an additional mechanism through which resveratrol affects the regulation of human colon cancer cell growth.

• BMB Reports
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• 제55권2호
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• pp.87-91
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• 2022

Aurora kinase is a family of serine/threonine kinases intimately associated with mitotic progression and the development of human cancers. Studies have shown that aurora kinases are important for the protein kinase C (PKC)-induced invasion of colon cancer cells. Recent studies have shown that aurora kinase A promotes distant metastasis by inducing epithelial-to-mesenchymal transition (EMT) in colon cancer cells. However, the role of aurora kinase A in colon cancer metastasis remains unclear. In this study, we investigated the effects of aurora kinase A on PKC-induced cell invasion, migration, and EMT in human SW480 colon cancer cells. Treatment with 12-O-tetradecanoylphorbol-13-acetate (TPA) changed the expression levels of EMT markers, increasing α-SMA, vimentin, and MMP-9 expression and decreasing E-cadherin expression, with changes in cell morphology. TPA treatment induced EMT in a PKC-dependent manner. Moreover, the inhibition of aurora kinase A by siRNAs and inhibitors (reversine and VX-680) suppressed TPA-induced cell invasion, migration, and EMT in SW480 human colon cells. Inhibition of aurora kinase A blocked TPA-induced vimentin and MMP-9 expression, and decreased E-cadherin expression. Furthermore, the knockdown of aurora kinase A decreased the transcriptional activity of NF-κB and AP-1 in PKC-stimulated SW480 cells. These findings indicate that aurora kinase A induces migration and invasion by inducing EMT in SW480 colon cancer cells. To the best of our knowledge, this is the first study that showed aurora kinase A is a key molecule in PKC-induced metastasis in colon cancer cells.

• 약학회지
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• 제52권5호
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• pp.402-406
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• 2008

Previously, we have shown that 1-furan-2-yl-3-pyridin-2-yl-propenone (FPP-3) has an anti-inflammatory activity in a rat paw-edema model. In the present study, we investigated an inhibitory effect of FPP-3 on the tumor necrosis factor (TNF)-${\apha}$-induced inflammatory cytokine response in HT-29 human colon epithelial cells. Treatment with FPP-3 significantly prevented the TNF-${\apha}$-induced attachment of leukocytes to HT-29 colon epithelial cells, which is one of the pathologic hallmarks in colon inflammation. The effect of FPP-3 was markedly superior than that of 5-aminosalicylic acid (5-ASA), a commonly used drug for the treatment of inflammatory bowel disease (IBD). The pretreatment with FPP-3 inhibited TNF-${\apha}$- induced monocyte chemoattractant protein (MCP)-1, interleukin (IL)-8 mRNA expressions. In addition, FPP-3 significantly suppressed TNF-${\apha}$-induced nuclear factor (NF)-${\kappa}B$ transcription activity. These results demonstrate that FPP-3 modulates intestinal inflammation via suppressing the NF-${\kappa}B$ dependent expressions of MCP-1 and IL-8, and suggest that FPP-3 may be a valuable agent for the treatment of IBD.

• Natural Product Sciences
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• 제12권1호
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• pp.38-43
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• 2006

Ilekudinol B is one of the flavonoids isolated from Weigela subsessilis (Caprifoliaceae). In the present study, the suppression effect of ilekudinol B on tumor necrosis factor $(TNF)-{\alpha}-induced$ cyclooxygenase-2 (COX-2) expression was investigated in human colon epithelial cell line HT-29. Interleukin-8 (IL-8) production and prostaglandin $E_2\;(PGE_2)$ secretion was measured by enzyme-linked immunosorbent assay (ELISA). COX-2 and nuclear factor $(NF)-{\kappa}B$ expression were determined by Western blot analysis. Ilekudinol B significantly inhibited $TNF-{\alpha}-induced$ secretion of IL-8 and prostaglandin $E_2\;(PGE_2)$ from the human colon epithelial cell line HT-29 in a concentration-dependent manner. In addition, ilekudinol B remarkably diminished $TNF-{\alpha}-induced$ COX-2 expression and $NF-{\kappa}B$ p65 subunit translocation to the nucleus. In conclusion, our results indicate that ilekudinol B may have anti-inflammatory activity on $TNF-{\alpha}-dependent$ colonic inflammation.

• Asian Pacific Journal of Cancer Prevention
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• 제15권7호
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• pp.2987-2991
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• 2014

Connexin 43 is an important gap junction protein in vertebrates and is known for its tumor suppressive properties. Cx43 is abundantly expressed in the human intestinal epithelial cells and muscularis mucosae. To explore the role of Cx43 in the genesis of human colon cancer, we performed the expression analysis of Cx43 in 80 cases of histopathologically confirmed and clinically diagnosed human colon cancer samples and adjacent control tissue and assessed correlations with clinicopathological variables. Western blotting using anti-Cx43 antibody indicated that the expression of Cx43 was significantly down regulated (75%) in the cancer samples as compared to the adjacent control samples. Moreover, immunohistochemical analysis of the tissue samples confirmed the down regulation of the Cx43 in the intestinal epithelial cells. Cx43 down regulation showed significant association (p<0.05) with the histological type and tumor invasion properties of the cancer. Our data demonstrated that loss of Cx43 may be an important event in colon carcinogenesis and tumor progression, providing significant insights about the tumor suppressive properties of the Cx43 and its potential as a diagnostic marker for colon cancer.

• Journal of Ginseng Research
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• 제42권3호
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• pp.288-297
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• 2018

Background: The incidence of colorectal cancer (CRC) is increasing, with metastasis of newly diagnosed CRC reported in a large proportion of patients. However, the effect of Korean Red Ginseng extracts (KRGE) on epithelial to mesenchymal transition (EMT) in CRC is unknown. Therefore, we examined the mechanisms by which KRGE regulates EMT of CRC in hypoxic conditions. Methods: Human CRC cell lines HT29 and HCT116 were incubated under hypoxic (1% oxygen) and normoxic (21% oxygen) conditions. Western blot analysis and real-time PCR were used to evaluate the expression of EMT markers in the presence of KRGE. Furthermore, we performed scratched wound healing, transwell migration, and invasion assays to monitor whether KRGE affects migratory and invasive abilities of CRC cells under hypoxic conditions. Results: KRGE-treated HT29 and HCT116 cells displayed attenuated vascular endothelial growth factor (VEGF) mRNA levels and hypoxia-inducible $factor-1{\alpha}$ ($HIF-1{\alpha}$) protein expression under hypoxic conditions. KRGE repressed Snail, Slug, and Twist mRNA expression and integrin ${\alpha}V{\beta}6$ protein levels. Furthermore, hypoxia-repressed E-cadherin was restored in KRGE-treated cells; KRGE blocked the invasion and migration of colon cancer cells by repressing $NF-{\kappa}B$ and ERK1/2 pathways in hypoxia. Conclusions: KRGE inhibits hypoxia-induced EMT by repressing $NF-{\kappa}B$ and ERK1/2 pathways in colon cancer cells.

• Food Science and Biotechnology
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• 제18권3호
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• pp.749-754
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• 2009

The polysaccharide (BB-pol) extracted from Bifidobacterium bifidum BGN4 showed growth inhibitory effects on several colon cancer cell lines such as HT-29 and HCT-116. To increase the yield of polysaccharide, B. bifidum BGN4 was cultured in various culture media with different compositions. When B. bifidum BGN4 was cultured in modified MRS broth containing phytic acid, the cells showed increased branch formation and enlarged morphology. The content of total carbohydrate and the ability of adhesion to intestinal epithelial cells were also increased by phytic acid. The polysaccharide obtained from the cells grown in the presence of phytic acid inhibited the proliferation of cancer cell lines such as HT-29 and MCF-7 cells but not normal colon cell line, FHC. Taken together, Bifidobacterium grown in the presence of phytic acid may confer enhanced beneficial function for the host.