• Journal of Nutrition and Health
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• v.34 no.2
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• pp.150-157
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• 2001

Intestinal absorption of dietary taurine is one of the regulatory component maintaining taurine homeostasis along with renal reabsorption, bile acid conjugation and secretion, and de nobo synthesis of taurine in mammals. Recent observations of decreased enterocytic levels of taurine in response to trauma, infection and surgical insults, postulate the possibility that intestinal taurine absorption might be impaired in such stressed conditions. The aim of the present study was to evaluate changes in enterocytic taurine transporter activity using the human intestinal colon carcinoma cell line, HT-29, in various stress-induced conditions. Pretreatment of the HT-29 cells with dexamethasone, a stress hormone(0.1,1,10 or 100$\mu$M) for 3 hrs, or with E coli heat-stable enterotoxin(10, 100, or 200nM) for 30 minutes in order to induce the condition of enterotoxigenic infection did not influence taurine uptake as compared to the value found in control cells. In contrast, pretreatment of the cells with cholera toxin(10, 100, 500, or 1000ng/ml)for 3hr or 24hr significantly decreased taurine uptake by HT-29 cells to 40~50% of the value found in untreated control cells. Kinetic studies of the taurine transporter activity were conducted in control and cholera toxin treated HT-29 cells with varying taurine concentrations(2~60$\mu$M) in the uptake medium. Pretreatment of the cells with cholera toxin(100ng/ml) for 3hr did not influence the Vmax, but resulted in a 55% increase in the Michaelis-Menten constant(Km) of the taurine transporter compared to those in control cells. These results suggest that cholera toxin-induced reduction in taurine transporter activity in HT-29 cells is associated with decreased affinity of the taurine transporter without altering the amount of transporter protein. Intestinal taurine absorption appears to be reduced in the condition of water-borne diseases caused by bacteria such as V. cholerae. This might influence the taurine status of infants and young children more readily, an age group in which the prevalence of intestinal infection is high and the role of intestinal absorption is crucial for maintaining the body taurine pool. (Korean J Nutrition 34(2) : 150-157, 2001)

• The Korea Journal of Herbology
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• v.22 no.2
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• pp.65-72
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• 2007

Objectives : In this study, we investigate that Euphorbiae lathyridis Semen extract contributes to growth inhibitory effect and anti-cancer activity on the HT-29 human colon cancer cells. Methods : Euphorbiae lathyridis Semen was extracted from the Semen of the plant using 80% Methanol. The Euphorbiae lathyridis Semen extract was treated to different concentrations for 24 hr, 4Shr or 72hr. Growth inhibitory effect was analyzed by measuring FACS study and MTT assay. Cell apoptosis was confirmed by surveying caspases cascades activation using Westem blot. Results : Exposure to Euphorbiae lathyridis Semen extract (0.4mg/ml) results in an inhibitory effect on cell growth in HT-29 cells. Growth inhibition by Euphorbiae lathyridis Semen extract in HT-29 cells was related with the inhibition of proliferation and induction of apoptosis. The Euphorbiae lathyridis Semen extract induces DNA fragmentation in HT-29 cells. Furthermore, Euphorbiae lathyridis Semen extract induces cell apoptosis through the activation of caspases-3, caspase-9 and PARP cleavage. Conclusion : Euphorbiae lathyridis Semen extract induces apoptosis in human colon cancer cells, therefore, we suggest that Euphorbiae lathyridis Semen extract can be used as a novel class of anti-cancer drugs.

• IMMUNE NETWORK
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• v.24 no.4
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• pp.29.1-29.18
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• 2024

NK cells belong to innate lymphoid cells and able to eliminate infected cells and tumor cells. NK cells play a valuable role in controlling viral infections. Also, they have the potential to shape the adaptive immunity via a unique crosstalk with the different immune cells. Murine models are important tools for delineating the immunological phenomena in viral infection. To decipher the immunological virus-host interactions, two major infection models are being investigated in mice regarding NK cell-mediated recognition: murine cytomegalovirus (MCMV) and lymphocytic choriomeningitis virus (LCMV). In this review, we recapitulate recent findings regarding the multifaceted role of NK cells in controlling LCMV and MCMV infections and outline the exquisite interplay between NK cells and other immune cells in these two settings. Considering that, infections with MCMV and LCMV recapitulates many physiopathological characteristics of human cytomegalovirus infection and chronic virus infections respectively, this study will extend our understanding of NK cells biology in interactions between the virus and its natural host.

• Parasites, Hosts and Diseases
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• v.51 no.1
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• pp.61-68
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• 2013

Entamoeba histolytica, which causes amoebic colitis and occasionally liver abscess in humans, is able to induce host cell death. However, signaling mechanisms of colon cell death induced by E. histolytica are not fully elucidated. In this study, we investigated the signaling role of NOX in cell death of HT29 colonic epithelial cells induced by E. histolytica. Incubation of HT29 cells with amoebic trophozoites resulted in DNA fragmentation that is a hallmark of apoptotic cell death. In addition, E. histolytica generate intracellular reactive oxygen species (ROS) in a contact-dependent manner. Inhibition of intracellular ROS level with treatment with DPI, an inhibitor of NADPH oxidases (NOXs), decreased Entamoebainduced ROS generation and cell death in HT29 cells. However, pan-caspase inhibitor did not affect E. histolytica-induced HT29 cell death. In HT29 cells, catalytic subunit NOX1 and regulatory subunit Rac1 for NOX1 activation were highly expressed. We next investigated whether NADPH oxidase 1 (NOX1)-derived ROS is closely associated with HT29 cell death induced by E. histolytica. Suppression of Rac1 by siRNA significantly inhibited Entamoeba-induced cell death. Moreover, knockdown of NOX1 by siRNA, effectively inhibited E. histolytica-triggered DNA fragmentation in HT29 cells. These results suggest that NOX1-derived ROS is required for apoptotic cell death in HT29 colon epithelial cells induced by E. histolytica.

• Food Science and Biotechnology
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• v.16 no.2
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• pp.260-264
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• 2007

Gleditsiae Semen (GS) has been used in both Korea and China as herbal medicine for the treatment of cephalalgia, catharsis, and other diseases. However, the apoptosis of GS against human cancer cells has not previously been investigated. The primary objective of this study was to determine the mechanisms inherent in GS-induced cytotoxicity and apoptosis, using methanolic extract of GS (GSE) in HT-29 human colon carcinoma cells. We found that GSE induced cytotoxicity in HT-29 cells in a dose-dependent manner, and this effect was verified via a lactate dehydrogenase release assay and a colony formation assay. In particular, HT-29 cells showed extensive cell death when treated with $50\;{\mu}g/mL$ of GSE; the calculated $IC_{50}$ value was $20\;{\mu}g/mL$. It induced characteristic apoptotic signs in HT-29 cells, including chromatin condensation and DNA fragmentation, occurring within 6-24 hr when the cells were treated at a concentration of $50\;{\mu}g/mL$. Interestingly, we detected the activation of caspase-3 and -9, but not caspase-8, and apoptotic bodies in GSE-treated HT-29 cells. Collectively, our results indicate that GSE induces apoptosis via a mitochondria-mediated apoptotic pathway, and these findings may be significant with regard to the development of a new drug for the treatment of human colon carcinoma cells.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.8
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• pp.3471-3476
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• 2014

Background: Aberrant expression of the microRNA-29 family is associated with tumorigenesis and cancer progression. As transport carriers, tumor-derived exosomes are released into the extracellular space and regulate multiple functions of target cells. Thus, we assessed the possibility that exosomes could transport microRNA-29c as a carrier and correlations between microRNA-29c and apoptosis of bladder cancer cells. Materials and Methods: A total of 28 cancer and adjacent tissues were examined by immunohistochemistry to detect BCL-2 and MCL-1 expression. Disease was Ta-T1 in 12 patients, T2-T4 in 16, grade 1 in 8, 2 in 8 and 3 in 12. The expression of microRNA-29c in cancer tissues was detected by quantitative reverse transcriptase PCR (QRT-PCR). An adenovirus containing microRNA-29c was used to infect the BIU-87 human bladder cancer cell line. MicroRNA-29c in exosomes was measured by QRT-PCR. After BIU-87 cells were induced by exosomes-derived microRNA-29c, QRT-PCR was used to detect the level of microRNA-29c. Apoptosis was examined by flow cytometry and BCL-2 and MCL-1 mRNA expressions were assessed by reverse transcription-polymerase chain reaction. Western blotting was used to determine the protein expression of BCL-2 and MCL-1. Results: The expressions of BCL-2 and MCL-1 protein were remarkably increased in bladder carcinoma (p<0.05), but was found mainly in the basal and suprabasal layers in adjacent tissues. The expression of microRNA-29c in cancer tissues was negatively correlated with the BCL-2 and MCL-1. The expression level of microRNA-29c in exosomes and BIU-87 cells from the experiment group was higher than that in control groups (p<0.05). Exosome-derived microRNA-29c induced apoptosis (p<0.01). Although only BCL-2 was reduced at the mRNA level, both BCL-2 and MCL-1 were reduced at the protein level. Conclusions: Human bladder cancer cells infected by microRNA-29c adenovirus can transport microRNA-29c via exosomes. Moreover, exosome-derived microRNA29c induces apoptosis in bladder cancer cells by down-regulating BCL-2 and MCL-1.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.4
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• pp.1871-1877
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• 2014

Enhancing of radioresponsiveness of tumors by using radiosensitizers is a promising approach to increase the efficacy of radiation therapy. Recently, the ethanolic extract of the medicinal plant, Derris scandens Benth has been identified as a potent radiosensitizer of human colon cancer HT29 cells. However, cell death mechanisms underlying radiosensitization activity of D scandens extract have not been identified. Here, we show that treatment of HT-29 cells with D scandens extract in combination with gamma irradiation synergistically sensitizes HT-29 cells to cell lethality by apoptosis and mitotic catastrophe. Furthermore, the extract was found to decrease Erk1/2 activation. These findings suggest that D scandens extract mediates radiosensitization via at least two distinct modes of cell death and silences pro-survival signaling in HT-29 cells.

• Journal of Microbiology and Biotechnology
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• v.17 no.12
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• pp.2042-2045
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• 2007

The effect of chitosan oligosaccharide (COS, 1 kDa${\gamma}$, 10 ng/ml IL-$1{\alpha}$, and 25 ng/ml TNF-${\alpha}$) in HT-29 cells. Inducible nitric oxide synthase (iNOS) expression induced by these cytokines was inhibited by COS. COS pretreatment inhibited the invasiveness of cytokines-treated HT-29 cells through Matrigel-coated membrane in a dose-dependent manner. COS also inhibited cytokines-induced matrix metalloproteinase (MMP)-2 activity. This study shows that proinflammatory cytokines induce NO production, iNOS expression, and invasiveness of human colorectal adenocarcinoma HT-29 cells. COS pretreatment inhibited cytokines-mediated NO production, iNOS expression, and invasiveness of HT-29 cells. These results provide sufficient information for the further development of COS as an antitumor metastatic agent for the treatment of colon cancer.

• Journal of Life Science
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• v.22 no.1
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• pp.55-61
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• 2012

Akt is known to play an important role in cell proliferation and differentiation, and is also over-expressed in several types of cancer cells. In this study, we explored the anti-proliferative effects of selenium in HT-29 colon cancer cells, mediated through effects on Akt and COX-2. Selenium treatments at different concentrations and for different durations inhibited proliferation of HT-29 colon cancer cells and increased apoptotic cell death. Selenium treatment decreased Akt phosphorylation and COX-2 expression. Treatment with LY294002 (an Akt inhibitor) decreased proliferation of HT-29 cells, while a combined treatment with LY294002 and selenium resulted in even further decreases in cell proliferation. Inactivation of Akt by Akt siRNA treatment abolished these inhibitory effects on cell growth. COX-2 expression decreased in Akt transfected cells compared to non-transfected cells. These results suggest that selenium induced both anti-proliferative and apoptotic effects by inhibiting Akt phosphorylation and COX-2 expression. Selenium treatment also appeared to induce synergistic anti-proliferative effects by inhibition of Akt in HT-29 colon cancer cells.

• Food Science and Biotechnology
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• v.14 no.6
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• pp.866-870
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• 2005

The 14 lactic acid bacteria (LAB) have been evaluated to determine the binding capacity to HT29 cell and Aflatoxin $B_1$ ($AFB_1$). The interaction of LAB to HT29 cells has been further investigated to identify the possibility of competing the binding sites with $AFB_1$. Of 14 LAB strains, Lactobacillus casei KCTC 3260 demonstrated the higher adhesiveness to HT29 and $AFB_1$ with the rate of 19.6% and 46.3%, respectively. In competitive analysis for binding sites, the adhesion of L. casei KCTC 3260 to HT29 cells was reduced with 100 nmol $AFB_1$ by 31.2%. The protoplast of L. casei KCTC 3260 showed no binding capacity to HT29 cells with increment of $AFB_1$ concentration, indicating that cell wall components might serve as a critical factor for the binding. To discriminate the major component influencing on L. casei KCTC 3260 binding to HT29 cells and $AFB_1$, four different pre-treatments (lipase, pronase E, sodium m-periodate, and urea) were employed. Of those, sodium m-periodate treatment caused the lower adhesion of L. casei KCTC 3260 to HT29 cells with the increment of $AFB_1$ concentration. These results indicated that carbohydrate moiety on the cell wall of L. casei KCTC 3260 might be the most critical component in binding to both HT29 cells and $AFB_1$.