• 대한임상검사과학회지
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• 제55권1호
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• pp.37-44
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• 2023

Enterotoxigenic Bacteroides fragilis (ETBF)는 염증성장 질환과 대장암을 유발하며 아연 의존성 metalloprotease인 B. fragilis toxin (BFT)를 분비한다. BFT는 epithelial cell의 E-cadherin을 80 kDa ectodomain과 33 kDa intracellular domain으로 분절을 유도한다. 생성된 E-cadherin intracellular domain은 순차적으로 γ-secretase에 의해 분절되어 28 kDa E-cadherin intracellular fragment은 아직까지 밝혀지지 않는 기작으로 분해된다. 본 연구에서는 BFT 유도 E-cadherin 분절로 인해 생성된 28 kDa E-cadherin intracellular fragment는 proteasome에 의해서 분해된다는 것을 확인하였다. 또한 BFT 유도 E-cadherin 분절 기작이 대장암 세포가 아닌 인간 유방암 세포주 BT-474 세포에서도 동일한 기작으로 일어남을 확인하였다. 마지막으로 staurosporine은 인간 유방암 세포주 MCF7 세포에서 E-cadherin의 분절을 유도하고 γ-secretase에 의한 E-cadherin intracellular domain의 분절이 일어났으나 proteasome에 의한 분해는 일어나지 않았다. 이러한 결과는 ETBF가 서식하는 대장이 아닌 유방에서도 BFT에 의한 E-cadherin 분절이 일어날 수 있으며 ETBF가 대장암 이외의 다른 암에도 관여할 수 있음을 시사한다.

• Toxicological Research
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• 제26권1호
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• pp.29-35
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• 2010

The present study was conducted to investigate the antimutagenic potential of the methanolic extract from the leaves of sweet potato (Ipomea batatas, IB) with the SOS chromotest (umu test) and Salmonella typhimurium TA 98 and TA 100. The anticarcinogenic effects were also studied by calculation of the $IC_{50}$ on human cancer cell lines and investigating the function of gap junction in rat liver epithelial cells. The IB extract inhibited dose-dependently the ${\beta}$-galactosidase activity induced spontaneously at concentration of more than 200 mg/ml in S. typhimurium TA 1535/pSK 1002, and decreased significantly (p < 0.01) the ${\beta}$-galactosidase activities induced by mutagen 6-chloro-9-[3-(2-chloroethylamino)proylamino]-2-methoxyacridine dihydrochloride (ICR) at dose of more than 0.4 mg/0.1 ml. The IB extract showed no effect on the spontaneous reversions of S. typhimurium TA 98 and 100 but benzo(${\alpha}$)pyrene (BaP)-stimulated reversions were decreased dose-dependently (p < 0.01) at the concentration of more than 100 mg/ml. The $IC_{50}$ value of stomach cancer cells was lower than that of normal rat liver epithelial cells, but the values of colon and uterine cancer cell lines were similar to those of normal rat liver epithelial cells. The transfer of dye through gap junctions was not affected by treatment of the IB extracts at any concentration during treatment periods. The simultaneously treatment of IB extract and 12-O-tetradecanoylphorbol-13-acetate (TPA) effectively prevented the inhibition of dye transfer induced by TPA 1 hour after treatment at all exposed concentrations. The number of gap junctions was significantly (p < 0.01) increased by the treatment with IB extract at concentrations of more than 40 ${\mu}g$/ml. The inhibition of the expression of gap junction proteins by TPA (0.01 ${\mu}g$/ml) was recovered dose dependently by the simultaneous treatment of IB extracts. Our data suggest that Ipomea batatas has antimutagenic and anticarcionogenic activity in vitro.

• 약학회지
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• 제54권2호
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• pp.91-96
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• 2010

Berberine, an isoquinoline alkaloid, has a wide range of pharmacological effects, including anti-inflammation. It has been reported that berberine inhibits experimental colitis through inhibition of IL-8, and that inhibitory effect of berberine on inflammatory cytokine expression is mediated through peroxisome proliferator activated receptor (PPAR)-$\gamma$. In this study, we examined the effects and action mechanism of berberine on the tumor necrosis factor (TNF)-$\alpha$-induced monocyte adhesion to HT29 human colonic epithelial cells, which is commonly used as an in vitro model of inflammatory bowel disease (IBD). Berberine significantly inhibited the TNF-$\alpha$-induced monocyte adhesion to HT29, which is similar to the effect of PDTC, a nuclear factor (NF)-$\kappa$B inhibitor. However, ciglitazone and GW, the ligands of PPAR-$\gamma$, did not suppress the TNF-$\alpha$-induced monocyte adhesion to HT29 cells. In addition, TNF-$\alpha$-induced chemokine expression and NF-$\kappa$B transcriptional activity were significantly inhibited by berberine in a concentration-dependent manner. The results suggest that inhibitory effect of berberine on colitis is mediated through suppression of NF-$\kappa$B and NF-$\kappa$B-dependent chemokine expression.

• Journal of Applied Biological Chemistry
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• 제61권2호
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• pp.119-124
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• 2018

두충(Eucommia ulmoides Oliver)잎 아세톤 추출물의 in vitro 항암 및 항산화 활성을 조사하였다. 두충잎 아세톤 추출물의 수율은 $1.13{\pm}0.033%$ (w/w)이었고, 총 페놀성 화합물 함량은 $36.7{\pm}1.96mg$ gallic acid equivalents/g-추출물로 나타났다. 세포증식을 절반 억제하는 추출물의 농도인 $GI_{50}$값은 사람의 암세포인 비소세포폐암세포(A549)에서 $53.4{\mu}g/mL$, 결장암세포(SNU-C4)에서 $53.8{\mu}g/mL$ 및 자궁경부암세포(HeLa)에서 $88.3{\mu}g/mL$이었고, 사람의 정상세포인 배아 폐 상피세포(L132)에서는 $153.9{\mu}g/mL$로 나타났다. 두충잎 아세톤 추출물은 사람의 정상세포에는 낮은 독성을 나타내면서 농도에 비례하여 사람의 비소세포폐암세포(A549)와 결장암세포(SNU-C4)의 증식을 효과적으로 억제하였다. DPPH 유리라디칼을 절반 소거하는 추출물의 농도인 $EC_{50}$값은 2 mg/mL 정도로 높게 나타났고, 환원력의 $EC_{50}$값은 $275.8{\mu}g/mL$, 지질과산화를 절반 저해하는 농도인 $EC_{50}$값은 $257.9{\mu}g/mL$이었다. 유근피 아세톤 추출물은 농도에 비례하여 우수한 환원력 및 지질과산화 억제활성을 보여주었다.

• Asian Pacific Journal of Cancer Prevention
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• 제16권11호
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• pp.4781-4786
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• 2015

Siberian ginseng (Eleutherococcus senticosus) is used primarily as an adaptogen herb and also for its immune stimulant properties in Western herbal medicine. Another closely related species used in East Asian medicine systems i.e. Kampo, TCM (Manchuria, Korea, Japan and Ainu of Hokkaido) and also called Siberian ginseng (Acanthopanax senticosus) also displays immune-stimulant and anti-cancer properties. These may affect tumour growth and also provide an anti-fatigue effect for cancer patients, in particular for those suffering from lung cancer. There is some evidence that a carbohydrate in Siberian ginseng may possess not only immune stimulatory but also anti-tumour effects and also display other various anti-cancer properties. Our study aimed to determine the inhibitory and also proliferative effects of a methanol plant extract of Siberan ginseng (E. senticosus) on various cancer and normal cell lines including: A-549 (small cell lung cancer), XWLC-05 (Yunnan lung cancer cell line), CNE (human nasopharyngeal carcinoma cell line), HCT-116 (human colon cancer) and Beas-2b (human lung epithelial). These cell lines were treated with an extract from E. senticosus that was evaporated and reconstituted in DMSO. Treatment of A-549 (small cell lung cancer) cells with E. senticosus methanolic extract showed a concentration-dependent inhibitory trend from $12.5-50{\mu}g/mL$, and then a plateau, whereas at 12.5 and $25{\mu}g/mL$, there is a slight growth suppression in QBC-939 cells, but then a steady suppression from 50, 100 and $200{\mu}g/mL$. Further, in XWLC-05 (Yunnan lung cancer cell line), E. senticosus methanolic extract displayed an inhibitory effect which plateaued with increasing dosage. Next, in CNE (human nasopharyngeal carcinoma cell line) there was a dose dependent proliferative response, whereas in Beas-2 (human lung epithelial cell line), an inhibitory effect. Finally in colon cancer cell line (HCT-116) we observed an initially weak inhibitory effect and then plateau.

• 생명과학회지
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• 제17권1호
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• pp.110-115
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• 2007

Tumor suppressor 유전자로알려진 early growth response gene 1 (EGR-1)에 있어 항산화 천연물인 apigenin과 그대사물인 isovitexin에 의한 장관 상피성 종양세포에 대하여 항종양 역할을 규명하였다. Apigenin 과 isovitexin은 대장암세포에서의 EGR-1 단백질의 발현을 9-12시간의 노출에 의해 농도 의존적으로 증가하였다. 또한 신호전달측면에서 이런 apigenin에 의한 EGR-1 유전자의 유도가 U0126 화합물에 의해 완벽하게 저해 받는 것으로 보아 ERK1/2 MAP kinase pathway의 이 신호전달계에서의 관여를 보여주었다. 본 연구에서 apigenin에 의해 농도 의존적으로 대장암세포의 세포활성의 저해를 MTT assay를 통해 보였고, 또한 EGR-1 siRNA를 transfectien한 세포의 경우 이런 apigenin에 의한 세포활성의 저해효과를 완화하였다. 따라서 apigenin에 의한 항종암세포 세포활성 억제에 있어 EGR-1의 중요성을 보여 준다. 이런 EGR-1에 의해 유도되는 유전자중 대표적으로 NAG-1 유전자의 경우 apigenin과 isovitexin에 의해 24-48시간에 발현이 증가하였다. 결론적으로 암세포 증식억제활성이 있고 apoptosis 유도효과가 있는 NAG-1의 유도에 의해 대장암 세포의 세포활성이 억제된 것으로 의미되고 향후 apigenin 유도의 NAG-1유전자에 의한 암세포증식의 억제기전에 대한 명확한 연구가 요구된다.

• Journal of Applied Biological Chemistry
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• 제59권2호
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• pp.133-136
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• 2016

유근피 아세톤 추출물의 항산화 및 암세포 증식억제 활성을 확인하였다. 유근피 아세톤 추출물의 농도에 비례하여 유리라디칼 소거활성($EC_{50}=36.7{\mu}g/mL$)과 환원력($EC_{50}=53.2{\mu}g/mL$)이 증가하였다. 유근피 아세톤 추출물은 정상 세포인 인체 배아 폐상피세포(L132)에는 독성이 낮으면서 농도에 비례하여 인체 폐암세포(A549, $GI_{50}=74.3{\mu}g/mL$)와 대장암세포(SNU-C4, $GI_{50}=92.8{\mu}g/mL$)의 증식을 효과적으로 억제하였다.

• Asian Pacific Journal of Cancer Prevention
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• 제13권12호
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• pp.6403-6407
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• 2012

Detoxifying enzymes are present in most epithelial cells of the human gastrointestinal tract where they protect against xenobiotics which may cause cancer. Induction of examples such as glutathione S-transferase (GST) and its thiol conjugate, glutathione (GSH) as well as NAD(P)H: quinoneoxidoreductase (NQO1) facilitate the excretion of carcinogens and thus preventing colon carcinogenesis. Pterostilbene, an analogue of resveratrol, has demonstrated numerous pharmacological activities linked with chemoprevention. This study was conducted to investigate the potential of pterostilbene as a chemopreventive agent using the HT-29 colon cancer cell line to study the modulation of GST and NQO1 activities as well as the GSH level. Initially, our group, established the optimum dose of 24 hours pterostilbene treatment using MTT assays. Then, effects of pterostilbene ($0-50{\mu}M$) on GST and NQO1 activity and GSH levels were determined using GST, NQO1 and Ellman assays, respectively. MTT assay of pterostilbene ($0-100{\mu}M$) showed no cytotoxicity toward the HT-29 cell line. Treatment increased GST activity in the cell line significantly (p<0.05) at 12.5 and $25.0{\mu}M$. In addition, treatment at $50{\mu}M$ increased the GSH level significantly (p<0.05). Pterostilbene also enhanced NQO1 activity significantly (p<0.05) at $12.5{\mu}M$ and $50{\mu}M$. Hence, pterostilbene is a potential chemopreventive agent capable of modulation of detoxifiying enzyme levels in HT-29 cells.

• Journal of Microbiology and Biotechnology
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• 제22권12호
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• pp.1629-1635
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• 2012

Previously, we demonstrated that the erythropoietin receptor (EpoR) is present on fibroblasts, where it regulates focal contact. Here, we assessed whether this action of EpoR is involved in the reduced cell adhesion observed in colonocytes exposed to Clostridium difficile toxin A. EpoR was present and functionally active in cells of the human colonic epithelial cell line HT29 and epithelial cells of human colon tissues. Toxin A significantly decreased activating phosphorylations of EpoR and its downstream signaling molecules JAK-2 (Janus kinase 2) and STAT5 (signal transducer and activator of transcription 5). In vitro kinase assays confirmed that toxin A inhibited JAK 2 kinase activity. Pharmacological inhibition of JAK2 (with AG490) abrogated activating phosphorylations of EpoR and also decreased focal contacts in association with inactivation of paxillin, an essential focal adhesion molecule. In addition, AG490 treatment significantly decreased expression of occludin (a tight junction molecule) and tight junction levels. Taken together, these data suggest that inhibition of JAK2 by toxin A in colonocytes causes inactivation of EpoR, thereby enhancing the inhibition of focal contact formation and loss of tight junctions known to be associated with the enzymatic activity of toxin A.

• 한국영양학회:학술대회논문집
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• 한국영양학회 1995년도 추계학술대회 초록
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• pp.11-34
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• 1995

Growth hormone (GH) plays a key role in regulating postnatal growth and can stimulate growth of animals by acting directly on specific receptors on the plasma membrane of tissues or indirectly through stimulating insulin-like growth factor (IGF)-I synthesis and secretion by the liver and other tissues. IGF-I and IGF-Ⅱ are polypeptides with structural similarity with proinsulin that stimulate cell proliferation by endocrine, paracrine and autocrine mechanisms. The initial event in the metabolic action of IGFs on target cells appears to be their binding to specific receptors on the plasma membrane. Current evidence indicates that the mitogenic actions of both IGFs are mediated primarily by binding to the type I IGF receptors, and that IGF action is also mediated by interactions with IGF-binding proteins (IGFBPs). Six distinct IGFBPs have been identified that are characterized by cell-specific interaction, transcriptional and post-translational regulation by many different effectors, and the ability to either potentiate or inhibit IGF actions. Nutritional deficiencies can have their devastating consequence during growth. Although IGF-I is the major mediator of GH's action on somatic growth, nutritional status of an organism is a critical regulator of IGF-I and IGFBPs. Various nutrient deficiencies result in decreased serum IGF-I levels and altered IGFBP levels, but the blood levels of GH are generally unchanged or elevated in malnutrition. Effects of protein, energy, vitamin C and D, and zinc on serum IGF and IGFBP levels and tissue mRNA levels were reviewed in the text. Multiple factors are involved in the regulation of intestinal epithelial cell growth and differentiation. Among these factors the nutritional status of individuals is the most important. The intestinal epithelium is an important site for mitogenic action of the IGFs in vivo, with exogenous IGF-I stimulating mucosal hyperplasia. Therefore, the IGF system appears to provide and important mechanism linking nutrition and the proliferation of intestinal epithelial cells. In order to study the detailed mechanisms by which intestinal mucosa is regulated, we have utilized IEC-6 cells, an intestinal epithelial cell line and Caco-2 cells, a human colon adenocarcinoma cell line. Like intestinal crypt cells analyzed in vivo or freshly isolated intestinal epithelial cells, IEC-6 cells and Caco-2 cells possess abundant quatities of both type Ⅰ and type Ⅱ IGF receptors. Exogenous IGFs stimulate, whereas addition of IGFBP-2 inhibits IEC-6 cell proliferation. To investigate whether endogenously secreted IGFBP-2 inhibit proliferation, IEC-6 cells were transfected with a full-length rat IGFBP-2 cDNA anti-sense expression construct. IEC-6 cells transfected with anti-sense IGFBP-2 protein in medium. These cells grew at a rate faster than the control cells indicating that endogenous IGFBP-2 inhibits proliferation of IEC-6 cells, probably by sequestering IGFs. IEC-6 cells express many characteristics of enterocyte, but do not undergo differentiation. On the other hand, Caco-2 cells undergo a spontaneous enterocyte differentiation. On the other hand, Caco-2 cells undergo a spontaneous enterocyte differentiation after reaching confluency. We have demonstrated that Caco-2 cells produce IGF-Ⅱ, IGFBP-2, IGFBP-3, and an as yet unidentified 31,000 Mr IGFBP, and that both mRNA and peptide secretion of IGFBP-2 and IGFBP-3 increased, but IGFBP-4 mRNA and protein secretion decreased after the cells reached confluency. These changes occurred in parallel to and were coincident with differentiation of the cells, as measured by expression of sucrase-isomaltase. In addition, Caco-2 cell clones forced to overexpress IGFBP-4 by transfection with a rat IGFBP-4 cDNA construct exhibited a significantly slower growth rate under serum-free conditions and had increased expression of sucrase-isomaltase compared with vector control cells. These results indicate that IGFBP-4 inhibits proliferation and stimulates differentiation of Caco-2 cells, probably by inhibiting the mitogenic actions of IGFs.