• Molecular & Cellular Toxicology
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• 제1권4호
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• pp.248-255
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• 2005

To understand the response of cancer cells to anticancer drugs at the gene expression level, we examined the gene expression changes in response to five anticancer drugs, 5-fluorouracil, cytarabine, cisplatin, paclitaxel, and cytochalasin D in NCI-H460 human lung cancer cells. Of the five drugs, 5-fluorouracil had the most distinctive gene expression signature. By clustering genes whose expression changed significantly, we identified three clusters with unique gene expression patterns. The first cluster reflected the up-regulation of gene expression by cisplatin, and included genes involved in cell death and DNA repair. The second cluster pointed to a general reduction of gene expression by most of the anticancer drugs tested. A number of genes in this cluster are involved in signal transduction that is important for communication between cells and reception of extracellular signals. The last cluster represented reduced gene expression in response to 5-fluorouracil, the genes involved being implicated in DNA metabolism, the cell cycle, and RNA processing. Since the gene expression signature of 5-fluorouracil was unique, we investigated it in more detail. Significance analysis of microarray data (SAM) identified 808 genes whose expression was significantly altered by 5-fluorouracil. Among the up-regulated genes, those affecting apoptosis were the most noteworthy. The down-regulated genes were mainly associated with transcription-and translation-related processes which are known targets of 5-fluorouracil. These results suggest that the gene expression signature of an anticancer drug is closely related to its physiological action and the response of caner cells.

• Biomolecules & Therapeutics
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• 제29권6호
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• pp.667-677
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• 2021

The elevated expression of the hyaluronan-mediated motility receptor (HMMR) is known to be highly associated with tumor progression in prostate cancer, but the molecular mechanisms underlying the regulation of HMMR expression remain unclear. Here, we report that mammalian target of rapamycin (mTOR) is a key regulator of HMMR expression, for which its kinase activity is required. Pharmacological inhibitors of mTOR, such as rapamycin and Torin2, markedly suppressed the mRNA level as well as the protein level of HMMR in LNCaP and PC-3 cells. Our data demonstrate that such regulation occurs at the transcription level. HMMR promoter reporter assays revealed that the transcription factor SRF is responsible for the mTOR-mediated transcriptional regulation of HMMR gene. Consistently, the suppression of HMMR expression by Torin2 was noticeably reversed by the overexpression of SRF. Moreover, our findings suggest that the SRF binding sites responsible for the transcriptional regulation of HMMR through the mTOR-SRF axis are located in HMMR promoter sequences carrying the first intron, downstream of the translational start site. Furthermore, the upregulation of HMMR by DHT was abolished by stimulation with rapamycin, prior to DHT treatment, suggesting that mTOR activity is required for the induction of HMMR expression by androgen. Collectively, our study provides new mechanistic insights into the role of mTOR/SRF/AR signaling in HMMR regulation in prostate cancer cells.

• Toxicological Research
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• 제22권2호
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• pp.95-102
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• 2006

Exposure to soluble nickel compound produces toxic effects on immune system, but the mechanism of action remains to be elucidated. Differential gene expression was studied to understand the potential molecular mechanism responsible for acute toxicity induced by nickel acetate in spleen cells. We exposed mouse spleen cells to nickel acetate with a nontoxic dose ($40{\mu}M$) and then extracted total RNA at 6 h and 12 h after exposure. The RNA was hybridized onto 10K mouse oligonucleotide microarrays, and data were analyzed using GeneSpring 7.1. Nickel had a modest effects on expression of many genes, in the range of 1.3-3 fold. The expression profile showed time-dependent changes in expression levels of differentially expressed genes, including some important genes related to cell cycle, apoptosis and DNA repair. In hierarchical cluster analysis of duplicate experiments, 111 genes were screened out. Out of these, 44 genes showing time- dependent up-regulation (>1.5 fold) and 38 genes showing down-regulation (>1.5 fold) at all time points were chosen for further analysis. The change in the expression of three genes (GPX1, GADD45B and FAIM) after nickel treatment was validated using RT-PCR. As a rule, a number of genes appear to be coordinately regulated between cell survival and cell death from nickel toxicity. In conclusion, changes in the gene profile in the spleen after nickel treatment are complex and genes with diverse functions are modulated. These findings will be contributed to the understanding of the complicated biological effects of nickel.

• BMB Reports
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• 제56권9호
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• pp.514-519
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• 2023

Methyltransferase-like 3 (METTL3), a key component of the m⁶A methyltransferase complex, regulates the splicing, nuclear transport, stability, and translation of its target genes. However, the mechanism underlying the regulation of METTL3 expression by alternative splicing (AS) remains unknown. We analyzed the expression pattern of METTL3 after AS in human tissues and confirmed the expression of an isoform retaining introns 8 and 9 (METTL3-IR). We confirmed the different intracellular localizations of METTL3-IR and METTL3 proteins using immunofluorescence microscopy. Furthermore, the endogenous expression of METTL3-IR at the protein level was different from that at the mRNA level. We found that 3'-UTR generation by intron retention (IR) inhibited the export of METTL3-IR mRNA to the cytoplasm, which in turn suppressed protein expression. To the best of our knowledge, this is the first study to confirm the regulation of METTL3 gene expression by AS, providing evidence that the suppression of METTL3 protein expression by IR is an integral part of the mechanism by which 3'-UTR generation regulates protein expression via inhibition of RNA export to the cytoplasm.

• Asian-Australasian Journal of Animal Sciences
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• 제18권5호
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• pp.747-754
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• 2005

Nutritional regulation of gene expression associated with growth and feeding behavior in avian species can become an important technique to improve poultry production according to the supply of nutrients in the diet. Insulin-like growth factor-I (IGF-I) found in chickens has been characterized to be a 70 amino acid polypeptide and plays an important role in growth and metabolism. Although it is been well known that IGF-I is highly associated with embryonic development and post-hatching growth, changes in the distribution of IGF-I gene expression throughout early- to late-embryogenesis have not been studied so far. We revealed that the developmental pattern of IGF-I gene expression during embryogenesis differed among various tissues. No bands of IGF-I mRNA were detected in embryonic liver at 7 days of incubation, and thereafter the amount of hepatic IGF-I mRNA was increased from 14 to 20 days of incubation. In eyes, a peak in IGF-I mRNA levels occurred at mid-embryogenesis, but by contrast, IGF-I mRNA was barely detectable in the heart throughout all incubation periods. In the muscle, no significant difference in IGF-I gene expression was observed during different stages of embryogenesis. After hatching, hepatic IGF-I gene expression as well as plasma IGF-I concentration increases rapidly with age, reaches a peak before sexual maturity, and then declines. The IGF-I gene expression is very sensitive to changes in nutritional conditions. Food-restriction and fasting decreased hepatic IGF-I gene expression and refeeding restored IGF-I gene expression to the level of fed chickens. Dietary protein is also a very strong factor in changing hepatic IGF-I gene expression. Refeeding with dietary protein alone successfully restored hepatic IGF-I gene expression of fasted chickens to the level of fed controls. In most circumstances, IGF-I makes a complex with specific high-affinity IGF-binding proteins (IGFBPs). So far, four different IGFBPs have been identified in avian species and the major IGFBP in chicken plasma has been reported to be IGFBP-2. We studied the relationship between nutritional status and IGFBP-2 gene expression in various tissues of young chickens. In the liver of fed chickens, almost no IGFBP-2 mRNA was detected. However, fasting markedly increased hepatic IGFBP-2 gene expression, and the level was reduced after refeeding. In the gizzard of well-fed young chickens, IGFBP-2 gene expression was detected and fasting significantly elevated gizzard IGFBP-2 mRNA levels to about double that of fed controls. After refeeding, gizzard IGFBP-2 gene expression decreased similar to hepatic IGFBP-2 gene expression. In the brain, IGFBP-2 mRNA was observed in fed chickens and had significantly decreased by fasting. In the kidney, IGFBP-2 gene expression was observed but not influenced by fasting and refeeding. Recently, we have demonstrated in vivo that gizzard and hepatic IGFBP-2 gene expression in fasted chickens was rapidly reduced by intravenous administration of insulin, as indicated that in young chickens the reduction in gizzard and hepatic IGFBP-2 gene expression in vivo stimulated by malnutrition may be, in part, regulated by means of the increase in plasma insulin concentration via an insulin-response element. The influence of dietary protein source (isolated soybean protein vs. casein) and the supplementation of essential amino acids on gizzard IGFBP-2 gene expression was examined. In both soybean protein and casein diet groups, the deficiency of essential amino acids stimulated chickens to increase gizzard IGFBP-2 gene expression. Although amino acid supplementation of a soybean protein diet significantly decreased gizzard IGFBP-2 mRNA levels, a similar reduction was not observed in chickens fed a casein diet supplemented with amino acids. This overview of nutritional regulation of IGF-I and IGFBP-2 gene expression in young chickens would serve for the establishment of the supply of nutrients to diets to improve poultry production.

• 한국환경성돌연변이발암원학회지
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• 제22권4호
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• pp.274-278
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• 2002

Phthalates, suspected endocrine disruptor, are plasticizer and solvent used in industry, and some phthalates are known as potential carcinogen. Most common human exposure to this compounds may occur with contaminated food. It may migrate into food from plastic wrap or may enter food from general environmental contamination, and it has become widespread environmental pollutants, thus leading to a variety of phthalates that possibly threaten the public health. Dibutyl phthalate (DBP) may playa part of cell proliferator, which mediates changes in gene expression and the metabolism of xenobiotics. An understanding of the role of DBP in modulating gene regulation should provide insight regarding mechanisms of DBP induced xenoestrogenic impact. To elucidate the type of genes that are associated with estrogenic activity induced by DBP at the dose (10$^{-8}$ M) appeared proliferating effects, the pattern of gene expression in MCF7 cells was compared between 17$\beta$-estradiol and DBP exposure in the cDNA microarray. From the results, it showed some differences of gene expression patterns between MCF7 cells treated with 17$\beta$-estradiol and DBP, and also DBP shows estrogenic potential with changes in estrogen-related gene expression levels.

• Journal of Microbiology and Biotechnology
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• 제28권2호
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• pp.181-189
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• 2018

Candida albicans is a major pathogenic fungus in humans, and meets at first the innate immune cells, such as macrophages, in its host. One important strategy of the host cell to kill C. albicans is to produce reactive oxygen species (ROS) by the macrophages. In response to ROS produced by the macrophages, C. albicans operates its defense mechanisms against them by expressing its oxidative stress response genes. Although there have been many research studies explaining the specific transcription factors and the expression of the oxidative stress genes in C. albicans, the regulation of the oxidative stress genes by chromatin structure is little known. Epigenetic regulation by the chromatin structure is very important for the regulation of eukaryotic gene expression, including the chromatin structure dynamics by histone modifications. Among various histone modifications, histone acetylation is reported for its direct relationship to the regulation of gene expression. Recent studies reported that histone acetyltransferases regulate genes to respond to the oxidative stress in C. albicans. In this review, we introduce all histone acetyltransferases that C. albicans contains and some papers that explain how histone acetyltransferases participate in the oxidative stress response in C. albicans.

• 한국발생생물학회지:발생과생식
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• 제15권1호
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• pp.25-30
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• 2011

Embryonic stem (ES) cells can self-renew maintaining the undifferentiated state. Self renewal requires many factors such as Oct4, Sox2, FoxD3, and Nanog. NF-${\kappa}B$ is a transcription factor involved in many biological activities. Expression and activity of NF-${\kappa}B$ increase upon differentiation of ES cells. Reportedly, Nanog protein directly binds to NF-${\kappa}B$ protein and inhibits its activity in ES cells. Here, we found a potential binding site of NF-${\kappa}B$ in the human Nanog promoter and postulated that NF-${\kappa}B$ protein may regulate expression of the Nanog gene. We used human embryonic carcinoma (EC) cells as a model system of ES cells and confirmed decrease of Nanog and increase of NF-${\kappa}B$ upon differentiation induced by retinoic acid. Although deletion analysis on the DNA fragment including NF-${\kappa}B$ binding site suggested involvement of NF-${\kappa}B$ in the negative regulation of the promoter, site-directed mutation of NF-${\kappa}B$ binding site had no effect on the Nanog promoter activity. Furthermore, no direct association of NF-${\kappa}B$ with the Nanog promoter was detected during differentiation. Therefore, we conclude that NF-${\kappa}B$ protein may not be involved in transcriptional regulation of Nanog gene expression in EC cells and possibly in ES cells.

• BMB Reports
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• 제32권5호
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• pp.456-460
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• 1999

The promoter of the HSV-1 VP16 gene contains binding sites for the cellular transcription factors such as USF, CTF, and Sp1, each of which affects basal level expression of the VP16 gene. Transcription of the VP16 gene was induced by viral immediate-early proteins, ICP0 and ICP4, in a synergistic manner but repressed by ICP22. To gain further insight into the role of ICP0 in the expression of the VP16 gene during virus infection, several mutants with deletions in each of their transcriptional regulatory elements were generated. According to transient gene expression assays of these mutants using the CAT gene as a reporter, the USF and CTF binding sites were necessary for efficient induction of the promoter in the presence of transfected ICP0 or during virus infection, whereas the Sp1 binding site had little effect on ICP0-mediated VP16 expression. These results indicate that the immediate early proteins of HSV-1 regulate expression of the VP16 gene during virus infection by modulating the activities of cellular transcription factors such as USF and CTF.

• 약학회지
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• 제56권5호
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• pp.326-332
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• 2012

Mast cells play pivotal pathologic roles in allergic disease involving T helper 2 (Th2) cytokine such as interleukin (IL)-4 and IL-13. Fisetin has been known as an anti-allergic agent having inhibitory effects on the IL-4 and IL-13 gene expressions in inflammatory immune cells. However, its molecular mechanisms for suppressive effects of fisetin on IL-4 and IL-13 in activated mast cells have been incompletely elucidated. In this study we found that fisetin significantly inhibited the phorbol 12-myristate 13-acetate (PMA) and ionomycin (PI)-induced production of IL-4 and IL-13 in mast cells. The levels of mRNA were dramatically decreased by fisetin, indicating the suppression might be regulated at the transcriptional levels. Western blot analysis of the nuclear expression of various transcription factors involved in the promoter activation indicated that suppression of c-Fos was prominent together with significant down-regulation of nuclear factor of activated T-cell (NF-AT) and NF-${\kappa}B$, but not c-Jun. Furthermore, the nuclear expression of GATA binding protein 2 (GATA-2) transcription factor was significantly down-regulated by fisetin. Taken together, our study indicated fisetin has suppressive effects on IL-4 and IL-13 gene expression through the regulation of selective transcription factors.