• Biomolecules & Therapeutics
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• v.23 no.2
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• pp.134-140
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• 2015

Conjugated linoleic acids (CLA) are a family of isomers of linoleic acid. CLA increases growth arrest and apoptosis of human colorectal cancer cells through an isomer-specific manner. ATF3 belongs to the ATF/CREB family of transcription factors and is associated with apoptosis in colorectal cancer. The present study was performed to investigate the molecular mechanism by which t10, c12-CLA stimulates ATF3 expression and apoptosis in human colorectal cancer cells. t10, c12-CLA increased an apoptosis in human colorectal cancer cells in dose dependent manner. t10, c12-CLA induced ATF3 mRNA and luciferase activity of ATF3 promoter in a dose-dependent manner. The responsible region for ATF3 transcriptional activation by t10, c12-CLA is located between -147 and -1850 of ATF3 promoter. mRNA stability of ATF3 was not affected by t10, c12-CLA treatment. t10, c12-CLA increases $GSK3{\beta}$ expression and suppresses IGF-1-stimulated phosphorylation of Akt. The knockdown of ATF3 suppressed expression of $GSK3{\beta}$ and NAG-1 and PARP cleavage. The results suggest that t10, c12-CLA induces apoptosis through ATF3-mediated pathway in human colorectal cancer cells.

• Journal of Life Science
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• v.32 no.3
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• pp.210-221
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• 2022

This study investigated the mechanisms underlying the anti-cancer effects of non-steroidal anti-inflammatory drugs (NSAIDs) in human cancer cells in combination with either N-[N-(3, 5-difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT), a γ-secretase inhibitor, or MHY2245, a new synthetic sirtuin 1 inhibitor. The results showed both DAPT and MHY2245 as novel chemosensitizers of human colon cancer KM12 and human hepatocellular carcinoma SNU475 cells to NSAIDs involving celecoxib and 2, 5-dimethyl celecoxib. The NSAID-induced cytotoxicity of these cells was significantly increased by DAPT and MHY2245 in a cyclooxygenase-2 independent manner. In addition, DAPT and MHY2245 reduced levels of p62, Notch1 intracellular domain, and multiple cancer stemness (CS)-related markers including Notch1, CD44, CD133, octamer-binding transcription factor 4, mutated p53 and c-Myc. However, the level of activating transcription factor 4 (ATF4) was enhanced, probably indicating the down-regulation of multiple CS-related markers by DAPT or MHY2245-mediated autophagy induction. Moreover, the NSAID-mediated reduction of p62/nuclear factor erythroid-derived 2-like 2 and CS-related marker proteins and the up-regulation of C/EBP homologous protein (CHOP)/ATF4 were accelerated by DAPT and MHY2245. As such, the combination of NSAID and either DAPT or MHY2245 resulted in higher cytotoxicity than NSAID alone by accelerating the down-regulation of multiple CS-related markers and PARP activation, indicating that both inhibitors promote NSAID-mediated autophagic cell death, possibly through the CHOP/ATF4 pathway. In conclusion, either combination strategy may be useful for the effective treatment of human cancer cells expressing CS-related markers.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.107-116
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• 2019

The global obesity epidemic and associated metabolic diseases require alternative biological targets for new therapeutic strategies. In this study, we show that a phytochemical sulfuretin suppressed adipocyte differentiation of preadipocytes and administration of sulfuretin to high fat diet-fed obese mice prevented obesity and increased insulin sensitivity. These effects were associated with a suppressed expression of inflammatory markers, induced expression of adiponectin, and increased levels of phosphorylated ERK and AKT. To elucidate the molecular mechanism of sulfuretin in adipocytes, we performed microarray analysis and identified activating transcription factor 3 (Atf3) as a sulfuretin-responsive gene. Sulfuretin elevated Atf3 mRNA and protein levels in white adipose tissue and adipocytes. Consistently, deficiency of Atf3 promoted lipid accumulation and the expression of adipocyte markers. Sulfuretin's but not resveratrol's anti-adipogenic effects were diminished in Atf3 deficient cells, indicating that Atf3 is an essential factor in the effects of sulfuretin. These results highlight the usefulness of sulfuretin as a new anti-obesity intervention for the prevention of obesity and its associated metabolic diseases.

• Journal of Ginseng Research
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• v.39 no.1
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• pp.61-68
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• 2015

Background: Korean Red Ginseng (KRG) is a representative traditional herbal medicine with many different pharmacological properties including anticancer, anti-atherosclerosis, anti-diabetes, and anti-inflammatory activities. Only a few studies have explored the molecular mechanism of KRG-mediated anti-inflammatory activity. Methods: We investigated the anti-inflammatory mechanisms of the protopanaxadiol saponin fraction (PPD-SF) of KRG using in vitro and in vivo inflammatory models. Results: PPD-SF dose-dependently diminished the release of inflammatory mediators [nitric oxide (NO), tumor necrosis factor-${\alpha}$, and prostaglandin $E_2$], and downregulated the mRNA expression of their corresponding genes (inducible NO synthase, tumor necrosis factor-${\alpha}$, and cyclooxygenase-2), without altering cell viability. The PPD-SF-mediated suppression of these events appeared to be regulated by a blockade of p38, c-Jun N-terminal kinase (JNK), and TANK (TRAF family member-associated NF-kappa-B activator)-binding kinase 1 (TBK1), which are linked to the activation of activating transcription factor 2 (ATF2) and interferon regulatory transcription factor 3 (IRF3). Moreover, this fraction also ameliorated HCl/ethanol/-induced gastritis via suppression of phospho-JNK2 levels. Conclusion: These results strongly suggest that the anti-inflammatory action of PPD-SF could be mediated by a reduction in the activation of p38-, JNK2-, and TANK-binding-kinase-1-linked pathways and their corresponding transcription factors (ATF2 and IRF3).

• Journal of Life Science
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• v.25 no.4
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• pp.473-480
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• 2015

The endoplasmic reticulum (ER) in the eukaryotic cells is the first compartment in the secretory pathway. Almost secretory proteins and membrane proteins are secreted through the ER, in which post-translational modifications occur via diverse signals from the ER lumen to the cytoplasm and nucleus. Only then are correctly-folded proteins secreted to the outside cells. Unfolded proteins that accumulate in the ER cause a kind of intracellular stress, ER stress, and activate an unfolded protein response (UPR) system. The 3 major transducers of the UPR are inositol requiring 1 (IRE1), PKR-like ER kinase (PERK) and activating transcription factor 6 (ATF6), all of which are ER transmembrane proteins. Recently, novel types of a new ATF6 family have been identified. Those commonly have an ER-transmembrane domain, a transcription-activation domain and a basic leucine zipper (bZIP) domain―Luman, OASIS, BBF2H7, CREBH and CREB4. Each factor functions by regulating the UPR in specific organs and tissues. Although the detailed molecular mechanisms of OASIS family members are unknown, in this study we comprehensively introduce these molecular signals.

• Journal of Life Science
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• v.22 no.4
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• pp.492-498
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• 2012

To investigate whether phytochemicals affect cancer cell viability, human colorectal HCT116 cells were treated with four different phytochemicals. Among these phytochemicals, curcumin is the strongest inhibitor of cell proliferation. In addition, it decreased cell viability in a dose-dependent manner. To unveil the molecular mechanisms involved in the inhibition of cell proliferation by curcumin, we carried out oligo DNA microarray analysis. We found that 137 genes were up-regulated more than 2-fold, and 141 genes were down-regulated more than 2-fold by 25 ${\mu}M$ curcumin treatment. Among the up-regulated genes, we selected 3 genes (ATF-3, GADD45A, and NR4A1) to confirm microarray data. The results of RT-PCR strongly agreed with those of the microarray data. Among the phytochemicals used in this study, curcumin is the strongest inducer of ATF3 expression, and increased ATF3 expression in a dose-dependent manner. Interestingly, FACS analysis showed that the inhibition of cell growth by curcumin was recovered by ATF3-siRNA transfection. Finally, we detected the changes of gene expression by ectopic expression of ATF3. The results indicated that many up-regulated genes were related to apoptosis. Overall, these results suggest that ATF3 may play an important role in the anti-proliferative activity of curcumin in human colorectal cancer cells.

• Proceedings of the Korea Society of Poultry Science Conference
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• 1999.11a
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• pp.34-50
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• 1999

A cDNA encoding chicken interferon-gamma (chIFN-${\gamma}$) was amplified from P34, a CD4$^{+}$ T-cell hybridoma by reverse transcription-polymerase chain reaction (RT-PCR) and cloned into pUC18. THe sequences of cloned PCR products were determined to confirm the correct cloning. Using this cDNA as probe, chicken genomic library from White Leghorn spleen was screened. Phage clones harboring chicken interferon-gamma (chIFN-${\gamma}$) were isolated and their genomic structure elucidated. The chIFN-${\gamma}$ contains 4 exons and 3 introns spanning over 14 kb, and follows the GT/AG rule for correct splicing at the exon/intron boundaries. The four exons encode 41, 26, 57 and 40 amino acids, respectively, suggesting that the overall structure of IFN-${\gamma}$ is evolutionairly conserved in mammalian and avian species. The 5’-untranslated region and signal sequences are located in exon 1. Several AT-rich sequences located in the fourth exon may indicate a role in mRNA turnover. The 5’-flanking region contains sequences homologous to the potential binding sites for the mammalian transcription factors, activator protein-1(AP-1) activator protein-2(AP-2) cAMP-response element binding protein(CREB), activating transcription factor(ATF), GATA-binding fator(GATA), upstream stimulating factor(USF), This suggests that the mechanisms underlying transcriptional regulation of chicken and mammalian IFN-${\gamma}$ genes may be similar.r.

• Biomedical Science Letters
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• v.26 no.1
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• pp.37-41
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• 2020

The hemolymph of Korean rhinoceros Allomyrina dichotoma consists of blood and lymph in which various kinds of proteins function physiologically. We have previously demonstrated that A. dichotoma hemolymph has the potential to treatment and prevent diabetes through activating transcription factor 3-gene (ATF3) regulation. In this study, we investigate the expression of Kruppel-like factor 4 (KLF4) in A. dichotoma hemolymph-treated INS-1 pancreatic β-cells. The new findings show that A. dichotoma hemolymph, which upregulates KLF4 gene expression in a dose-dependent and time-dependent manner. In addition, hemolymph combine with mild endoplasmic reticulum (ER) stress, which also differentially regulates KLF4 gene expression. These results may provide insights to KLF4 gene-related disease therapies through KLF4 gene regulation.

• Journal of Life Science
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• v.28 no.5
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• pp.615-620
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• 2018

Epigallocatechin-3-gallate (EGCG), one of catechins of green tea, has been known to possess anti-oxidation, anti-inflammation, and anti-cancer effects. The present study analyzed global gene expression changes in EGCG-treated HCT116 cells and p53-null HCT116 cells by oligo DNA microarray analysis. Among the differentially expressed genes in EGCG-treated HCT116 cells, four were selected that are known as tumor suppressor genes (activating transcription factor 3 [ATF3], cyclin dependent kinase inhibitor 1A [CDKN1A], DNA damage-inducible transcript 3 [DDIT3] and non-steroidal anti-inflammatory drug activated gene [NAG-1]) and their expression was compared to the expression of genes in p53-null HCT116 cells. We found that the expression of these genes was not dependent on their p53 status except for NAG-1, which was only up-regulated in HCT116. The results of RT-PCR and Western blot analysis showed that ATF3 up-regulation by EGCG was not affected by the presence of p53, whereas NAG-1 expression was not induced in p53-null HCT116 cells. We also detected ATF3 and NAG-1 expression changes through genistein and resveratrol treatment. Interestingly, genistein could not up-regulate ATF3 regardless of p53 status, but genistein could induce NAG-1 only in HCT116 cells. Resveratrol could significantly induce NAG-1 as well as ATF3 independent of p53 presence. These results indicate that EGCG, genistein and resveratrol may have different anti-cancer effects. Overall, the results of this study may help to increase our understandings of molecular mechanisms on anti-cancer activities mediated by EGCG, genistein and resveratrol in human colorectal cancer cells.

• Journal of Life Science
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• v.30 no.3
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• pp.285-290
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• 2020

Foot-and-mouth disease virus (FMDV), a member of the genus Aphthovirus in the Picornaviridae family, affects wild and domesticated ruminants and pigs. FMDV causes various clinical symptoms, including severe inflammation in infected tissue. Genome RNA of FMDV shows a positive single-strand chain approximately 8.3 kb long and encodes a single long open reading frame (ORF). The ORF is translated into structural and non-structural proteins by viral proteases. The FMDV 2C protein is one of the non-structural proteins encoded by FMDV and plays a critical role in FMD pathogenesis, including inflammation, apoptosis, and viral replication. In this study, we examined whether FMDV 2C induces intracellular expression of pro-inflammatory cytokine tumor necrosis factor alpha (TNFα). FMDV 2C expression in pig IBRS-2 cells increased mRNA and protein expression of TNFα at the transcriptional level via activation of TNFα promoter. Treatment with 4-phenylbutyric acid, an endoplasmic reticulum (ER) stress reducer, decreased TNFα expression induced by FMDV 2C. Activating transcription factor 4 (ATF4), a transcription factor mediating ER stress response, induced transactivation of TNFα promoter and expression of mRNA and protein of TNFα. However, the dominant negative mutant of ATF4 did not induce FMDV 2C-mediated TNFα expression. The results indicate that FMDV 2C protein increases clinical inflammation via ATF4-mediated TNFα expression and is associated with ER stress induction.