• Food Science of Animal Resources
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• v.32 no.5
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• pp.612-617
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• 2012

The antioxidant, antimicrobial, and cytotoxic activities of ovotransferrin were investigated in vitro. The antioxidant capacity of ovotransferrin was evaluated using the 2,2-Diphenyl-1-picryl hydrazyl (DPPH) radical scavenging method, antimicrobial effects using the agar well diffusion method, and cytotoxicity using the 3-(4,5-dimethylthizol-2-yl)-2,5-diphenylatetetrazolium bromide (MTT) assay. The DPPH radical-scavenging capacity of ovotransferrin at 1 mg/mL level reached approximately 60% after 48 h of reaction. The antimicrobial effects of ovotransferrin against common food-borne pathogens, Staphylococcus aureus KCCM 32395, Bacillus cereus KCCM 40935, Listeria monocytogenes ATCC 15313, Escherichia coli O157:H7 ATCC 43895, and Helicobacter pylori HpKCTC 26695 were dose dependant. Gram-positive bacteria was more sensitive to ovotransferrin than gram-negative bacteria. Ovotransferrin showed stronger antimicrobial effect against L. monocytogenes than other gram-positive bacteria tested. The cytotoxicity of ovotransferrin was evaluated in human cancer cell lines, various tissue origins, including the larynx (Hep-2), stomach (AGS), lung (SK-MES-1), liver (HepG2), breast (MCF-7), cervix (HeLa), and colon (HT-29). Ovotransferrin displayed relatively high cytotoxicity (${\leq}60%$ inhibition effects) at 40 mg/mL. At lower concentrations (${\leq}10mg/mL$), however, ovotransferrin cytotoxic effects were not significant in all cancer cell lines tested. These results indicated that ovotransferrin has potential to be used as an antioxidant or antimicrobial agent in foods or a pharmaceutical agent against cancers.

• Korean Journal of Medicinal Crop Science
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• v.18 no.1
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• pp.34-39
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• 2010

Machilus thunbergii was an important medicinal resource and distributed widely in China. In this study, the bioactivities of dichloromethane fraction (DF) and water fraction (AF) from Machilus thunbergii methanol extract were investigated. Total phenolic contents of DF and AF were 57.90 mg Gal/g and 189.92 mg Gal/g, and total flavonoid contents were 17.34 mg Que/g and 58.38 mg Que/g respectively. The $EC_{50}$ for DPPH radical scavenging activity of DF and AF were $24.37\;{\mu}g/m{\ell}$ and $2.10\;{\mu}g/m{\ell}$. Reducing power and hydroxyl radical scavenging activities of AF were higher than those of DF. The $\alpha$-glucosidase inhibitory activity of AF ($IC_{50}\;=\;1.13\;{\mu}g/m{\ell}$) was higher than that of DF ($IC_{50}\;=\;5.34\;{\mu}g/m{\ell}$). The cell viability was showed that only the DF had anti-proliferation effect on human cancer cell HT-29. These results suggested that both the DF and AF extract of Machilus thunbergii were potential materials for anti-diabetes and functional food for their radical scavenging activity.

• Ocean and Polar Research
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• v.38 no.2
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• pp.129-137
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• 2016

This study aimed to isolate and characterize sulfated polysaccharides (SPs) from Iridaea cordata and evaluate their anticancer activity. SPs of the Antarctic red seaweed were obtained by $CaCl_2$ (SP1) and ethanol precipitations (SP2) following diluted acid extraction at room temperature. Yields of SP1 and SP2 were approximately 14% and 23%, respectively, of the dry weight of red seaweed. The average molecular mass of the SP1 and SP2 was estimated about $1.84{\times}10^3$ and $1.42{\times}10^3kDa$, respectively, by size-fractionation High-Performance Liquid Chromatography (HPLC). From the High-Performance Anion-Exchange Chromatography-Pulsed Amperometric Detection (HPAEC-PAD) analysis, the main monosaccharide was galactose with glucose and fucose as minor components. The sulfate content of SP2 (40.4%) was slightly higher than that of SP1 (33.8%). The FT-IR spectra also showed characteristic band of carrageenan-like sulfated polysaccharides. Taken together the SPs are thought to be carrageenan-like sulfated galactan. The polysaccharides (SPs) from I. cordata exhibited weak antitumor activity against PC-3 (prostate cancer), HeLa (cervical cancer), and HT-29 (human colon adenocarcinoma). To our knowledge, this is the first data on biological activity of the Antarctic red seaweed I. cordata.

• Journal of Microbiology and Biotechnology
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• v.22 no.2
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• pp.170-175
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• 2012

Clostridium difficile toxin A glucosylates Rho family proteins, resulting in actin filament disaggregation and cell rounding in cultured colonocytes. Given that the cellular toxicity of toxin A is dependent on its receptor binding and subsequent entry into the cell, we herein sought to identify additional colonocyte proteins that might bind to toxin A following its internalization. Our results revealed that toxin A interacted with ERK1 and ERK2 in two human colonocyte cell lines (NCM460 and HT29). A GST-pulldown assay also showed that toxin A can directly bind to ERK1 and ERK2. In NCM460 cells exposed to PMA (an ERK1/2 activator), the phosphorylation of ERK1/2 did not affect the interaction between toxin A and ERK1/2. However, an in vitro kinase assay showed that the direct binding of toxin A to ERK1 or ERK2 inhibited their kinase activities. These results suggest a new molecular mechanism for the cellular toxicity seen in cells exposed to toxin A.

• Korean Journal of Food Science and Technology
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• v.49 no.4
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• pp.377-382
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• 2017

The objective of this study was to isolate and characterize lactic acid bacteria (LAB) exhibiting cholesterol-lowering activity from the Korean traditional fermented food, kimchi. The previously isolated LAB strains were assessed for cholesterol-lowering efficacy in the presence of 0.1% cholesterol. All LAB strains tested in this study were able to assimilate cholesterol at varying levels, ranging from 35.0 to 99.4%. Among them, the Lactobacillus plantarum FMB 31 strain exhibited the highest cholesterol-lowering effect with 99.4% cholesterol removal efficiency. The strain was stable in the presence of acid, bile, and salt stress, and showed high adherence on HT-29 cells, a human colon line. In addition, the LAB strain showed no pathogenic properties such as the production of hemolysin and biogenic amines. Thus, this study suggests that the L. plantarum FMB 31 strain isolated from kimchi can be a potential source of probiotic products with strong cholesterol-lowering effect.

• Nutrition Research and Practice
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• v.16 no.2
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• pp.161-172
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• 2022

BACKGROUND/OBJECTIVES: Colorectal cancer (CRC) is the third most common cancer worldwide and has a high recurrence rate, which is associated with cancer stem cells (CSCs). β-carotene (BC) possesses antioxidant activity and several anticancer mechanisms. However, no investigation has examined its effect on colon cancer stemness. MATERIALS/METHODS: CD133⁺CD44⁺ HCT116 and CD133⁺CD44⁺ HT-29 cells were isolated and analyzed their self-renewal capacity by clonogenic and sphere formation assays. Expressions of several CSCs markers and Wnt/β-catenin signaling were examined. In addition, CD133⁺CD44⁺ HCT116 cells were subcutaneously injected in xenograft mice and analyzed the effect of BC on tumor formation, tumor volume, and CSCs markers in tumors. RESULTS: BC inhibited self-renewal capacity and CSC markers, including CD44, CD133, ALDH1A1, NOTCH1, Sox2, and β-catenin in vitro. The effects of BC on CSC markers were confirmed in primary cells isolated from human CRC tumors. BC supplementation decreased the number and size of tumors and delayed the tumor-onset time in xenograft mice injected with CD133⁺CD44⁺ HCT116 cells. The inhibitory effect of BC on CSC markers and the Wnt/β-catenin signaling pathway in tumors was confirmed in vivo as well. CONCLUSIONS: These results suggest that BC may be a potential therapeutic agent for colon cancer by targeting colon CSCs.

• The Korean Journal of Physiology and Pharmacology
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• v.28 no.3
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• pp.265-273
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• 2024

This study aims to explore possible effect of RNA polymerase I subunit D (POLR1D) on proliferation and angiogenesis ability of colorectal cancer (CRC) cells and mechanism herein. The correlation of POLR1D and Yin Yang 1 (YY1) expressions with prognosis of CRC patients in TCGA database was analyzed. Quantitative realtime polymerase chain reaction (qRT-PCR) and Western blot were applied to detect expression levels of POLR1D and YY1 in CRC cell lines and CRC tissues. SW480 and HT-29 cells were transfected with si-POLR1D or pcDNA3.1-POLR1D to achieve POLR1D suppression or overexpression before cell migration, angiogenesis of human umbilical vein endothelial cells were assessed. Western blot was used to detect expressions of p38 MAPK signal pathway related proteins and interaction of YY1 with POLR1D was confirmed by dual luciferase reporter gene assay and chromatin immunoprecipitation (ChIP). TCGA data showed that both POLR1D and YY1 expressions were up-regulated in CRC patients. High expression of POLR1D was associated with poor prognosis of CRC patients. The results showed that POLR1D and YY1 were highly expressed in CRC cell lines. Inhibition or overexpression of POLR1D can respectively suppress or enhance proliferation and angiogenesis of CRC cells. YY1 inhibition can suppress CRC progression and deactivate p38 MAPK signal pathway, which can be counteracted by POLR1D overexpression. JASPAR predicted YY1 can bind with POLR1D promoter, which was confirmed by dual luciferase reporter gene assay and ChIP. YY1 transcription can up-regulate POLR1D expression to activate p38 MAPK signal pathway, thus promoting proliferation and angiogenesis ability of CRC cells.

• Journal of Life Science
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• v.28 no.8
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• pp.885-891
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• 2018

Clostridium difficile (C. difficile) toxin A is known to cause acute gut inflammation in humans and animals by triggering cytoskeletal disorganization in gut epithelial cells. In human colonocytes, toxin A blocks microtubule assembly by directly increasing the enzymatic activity of histone deacetylase-6 (HDAC-6), a tubulin-specific deacetylase, thereby markedly decreasing tubulin acetylation, which is essential for microtubule assembly. Microtubule assembly dysfunction-associated alterations (i.e., toxin A-exposed gut epithelial cells) are believed to trigger barrier dysfunction and gut inflammation downstream. We recently showed that potassium acetate blocked toxin A-induced microtubule disassembly by inhibiting HDAC-6. Herein, we tested whether acetic acid (AA), another small acetyl residue-containing agent, could block toxin A-induced tubulin deacetylation and subsequent microtubule assembly. Our results revealed that AA treatment increased tubulin acetylation and enhanced microtubule assembly in an HT29 human colonocyte cell line. AA also clearly increased tubulin acetylation in murine colonic explants. Interestingly, the AA treatment also alleviated toxin A-induced tubulin deacetylation and microtubule disassembly, and MTT assays revealed that AA reduced toxin A-induced cell toxicity. Collectively, these results suggest that AA can block the ability of toxin A to cause microtubule disassembly-triggered cytoskeletal disorganization by blocking toxin A-mediated deacetylation of tubulin.

• Biomolecules & Therapeutics
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• v.28 no.6
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• pp.561-568
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• 2020

We examined the anticancer effects of a novel sirtuin inhibitor, MHY2256, on HCT116 human colorectal cancer cells to investigate its underlying molecular mechanisms. MHY2256 significantly suppressed the activity of sirtuin 1 and expression levels of sirtuin 1/2 and stimulated acetylation of forkhead box O1, which is a target protein of sirtuin 1. Treatment with MHY2256 inhibited the growth of the HCT116 (TP53 wild-type), HT-29 (TP53 mutant), and DLD-1 (TP53 mutant) human colorectal cancer cell lines. In addition, MHY2256 induced G0/G1 phase arrest of the cell cycle progression, which was accompanied by the reduction of cyclin D1 and cyclin E and the decrease of cyclin-dependent kinase 2, cyclin-dependent kinase 4, cyclin-dependent kinase 6, phosphorylated retinoblastoma protein, and E2F transcription factor 1. Apoptosis induction was shown by DNA fragmentation and increase in late apoptosis, which were detected using flow cytometric analysis. MHY2256 downregulated expression levels of procaspase-8, -9, and -3 and led to subsequent poly(ADP-ribose) polymerase cleavage. MHY2256-induced apoptosis was involved in the activation of caspase-8, -9, and -3 and was prevented by pretreatment with Z-VAD-FMK, a pan-caspase inhibitor. Furthermore, the autophagic effects of MHY2256 were observed as cytoplasmic vacuolation, green fluorescent protein-light-chain 3 punctate dots, accumulation of acidic vesicular organelles, and upregulated expression level of light-chain 3-II. Taken together, these results suggest that MHY2256 could be a potential novel sirtuin inhibitor for the chemoprevention or treatment of colorectal cancer or both.

• Journal of the Korean Society of Food Science and Nutrition
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• v.37 no.2
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• pp.148-153
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• 2008

We investigated the growth inhibitory effect of Salicornia herbacea L. (SH) on human cancer cell lines in vitro. SH was extracted with methanol (SHM), followed by further fractionation into four subfractions according to polarity: hexane (SHMH), methanol (SHMM), butanol (SHMB), and aqueous (SHMA) soluble fractions. We determined the growth inhibitory effect of these fractions against human cancer cell lines using MTT assay. Among the four subfractions of SHM, the SHMM showed the strongest cytotoxic effects on cancer cell lines. We also observed quinone reductase (QR)-inducing effect of methanol layer (SHMM) on HepG2 cells and it was determined to be 3.00 at $100\;{\mu}g/mL$ level compared to the control value of 1.0. The SHMM showed the highest induction activity of quinone reductase on HepG2 cells among the partition layers. The present work suggests that SH merits further study to confirm its chemopreventive potential.