• Journal of Life Science
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• v.10 no.2
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• pp.39-44
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• 2000

Trichostatin A (TSA) is a Streptomyces product, which inhibits the enzyme activity of histone deacetylase. It is also known as an inducer of apoptosis in several human cancer cell lines. In this study, we investigated the mechanism of apoptosis induced by TSA in MDA-MB-231 human breast carcinoma cells. The cytotoxicity of TSA on MDA-MB-231 cells was assessed by MTT assay. The cell viability was decreased dose-dependently and the IC\ulcorner value was about 100 ng/ml after 48 h treatment with TSA. Morphological change and DNA ladder formation, the biochemical hallmarks of apoptotic cell death, were observed after treatment of TSA in a concentration-dependent manner, which was accompanied with cleavage of poly(ADP-ribose) polymerase and $\beta$-catenin, and activation of caspase-3. TSA treatment up-regulated the expression of a cyclin-dependent kinase inhibitor p21 (Wafl/Cip1) protein, a key regulatory protein of the cell cycle. However, there is no detectable change of both Bcl-2 and Bax expressions. These results demonstrated that TSA might inhibit cell growth through apoptosis in human breast carcinoma MDA-MB-231 cells.

• Biomolecules & Therapeutics
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• v.19 no.3
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• pp.282-287
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• 2011

Sirt1, a nicotinamide adenine dinucleotide ($NAD^+$)-dependent histone deacetylase, is known to deacetylate a number of proteins that are involved in various cellular pathways such as the stress response, apoptosis and cell growth. Modulation of the stress response by Sirtuin 1 (Sirt1) is achieved by the deacetylation of key proteins in a cellular pathway, and leads to a delay in the onset of cancer or aging. In particular, Sirt1 is known to play an important role in maintaining genomic stability, which may be strongly associated with a protective effect during tumorigenesis and during the onset of aging. In these studies, Sirt1 was generated in stably expressing cells and during the stimulation of DNA damage to examine whether it promotes survival. Sirt1 expressing cells facilitated the repair of DNA damage induced by either ionizing radiation (IR) or bleomycin (BLM) treatment. Fastened damaged DNA repair in Sirt1 expressing cells corresponded to prompt activation of Chk2 and ${\gamma}$-H2AX foci formation and promoted survival. Inhibition of Sirt1 enzymatic activity by a chemical inhibitor, nicotinamide (NIC), delayed DNA damage repair, indicating that promoted DNA damage repair by Sirt1 functions to induce survival when DNA damage occurs.

• Journal of Animal Reproduction and Biotechnology
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• v.35 no.2
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• pp.163-170
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• 2020

Partheno Embryo's research is known to play a very important role in identifying the development of embryonic cells or analyzing the genetic mechanisms of embryonic development, but the information on apoptosis formed during the early stage of development on Partheno Embryo is very little. Therefore, this study analyzed whether the embryonic cell death of unit embryos can be inhibited by adding Scriptaid, one of HDACi, which plays a role in demethylation of histone proteins as a method of regulating the cell cycle in the early embryo development of Partheno Embryo. As a result, the differentiation rate was higher in the group that added Scriptaid and FBS, but the cellular development was higher in the group that added pregnant serum to Scriptaid. As a result of analyzing the expression of the gene through IF and PCR, the group with the addition of gestational serum increased the expression of BCL2 and PCNA, which affects the anti-Casp3 action in cell survival. In addition, it is interpreted that treatment of Scriptaid for 16 hours, rather than 24 h treatment lowers the expression of Casp-3, a representative factor of apoptosis, and also increases embryonic development, thus affecting early embryo development. Therefore, it is concluded that the 16-hour treatment of Scriptaid and the use of gestational serum will inhibit cell death in the early embryonic development and increase the development rate of the embryo.

• The Plant Pathology Journal
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• v.32 no.3
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• pp.182-189
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• 2016

Together with the Fusarium graminearum species complex, F. culmorum is a major member of the causal agents of Fusarium head blight on cereals such as wheat, barley and corn. It causes significant yield and quality losses and results in the contamination of grain with mycotoxins that are harmful to humans and animals. In Korea, F. culmorum is listed as a quarantine fungal species since it has yet to be found in the country. In this paper, we report that two isolates (J1 and J2) of F. culmorum were collected from the air at a rice paddy field in Korea. Species identification was confirmed by phylogenetic analysis using multilocus sequence data derived from five genes encoding translation elongation factor, histone H3, phosphate permease, a reductase, and an ammonia ligase and by morphological comparison with reference strains. Both diagnostic PCR and chemical analysis confirmed that these F. culmorum isolates had the capacity to produce nivalenol, the trichothecene mycotoxin, in rice substrate. In addition, both isolates were pathogenic on wheat heads and corn stalks. This is the first report on the occurrence of F. culmorum in Korea.

• Biomolecules & Therapeutics
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• v.27 no.3
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• pp.283-289
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• 2019

Brain aging induces neuropsychological changes, such as decreased memory capacity, language ability, and attention; and is also associated with neurodegenerative diseases. However, most of the studies on brain aging are focused on neurons, while senescence in astrocytes has received less attention. Astrocytes constitute the majority of cell types in the brain and perform various functions in the brain such as supporting brain structures, regulating blood-brain barrier permeability, transmitter uptake and regulation, and immunity modulation. Recent studies have shown that SIRT1 and SIRT2 play certain roles in cellular senescence in peripheral systems. Both SIRT1 and SIRT2 inhibitors delay tumor growth in vivo without significant general toxicity. In this study, we investigated the role of tenovin-1, an inhibitor of SIRT1 and SIRT2, on rat primary astrocytes where we observed senescence and other functional changes. Cellular senescence usually is characterized by irreversible cell cycle arrest and induces senescence- associated ${\beta}$-galactosidase (SA-${\beta}$-gal) activity. Tenovin-1-treated astrocytes showed increased SA-${\beta}$-gal-positive cell number, senescence-associated secretory phenotypes, including IL-6 and IL-$1{\beta}$, and cell cycle-related proteins like phospho-histone H3 and CDK2. Along with the molecular changes, tenovin-1 impaired the wound-healing activity of cultured primary astrocytes. These data suggest that tenovin-1 can induce cellular senescence in astrocytes possibly by inhibiting SIRT1 and SIRT2, which may play particular roles in brain aging and neurodegenerative conditions.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.64 no.4
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• pp.384-394
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• 2019

We have investigated the effects of ambient temperature on the growth of wheat in Korea. The differences in the growth phase of wheat were compared according to the temperature treatment. The productive tiller number and dry weight were decreased in a plot under a higher temperature treatment. We found that the growth of Jinpum was different from that of the alternative wheat cultivars, which were bred in Korea, at 50 days after treatment. While the Jinpum wheat grown at 17℃ showed vegetative stage growth, that grown in the 23℃ growth chamber entered the heading and flowering stage. The differences in the expression of 16 genes known to be involved in high-temperature responses were checked by using Jinpum wheat 50 days after two temperature treatments (17℃ and 23℃), which showed apparent differences in expression between the higher and lower temperatures during the growth phase. In the 23℃ treatment samples, the genes with increased expression were HSP70, HSP101, VRN2, ERF1, TAA1, YUCCA2, GolS, MYB73, and Histone H2A, while the genes with decreased expression were VRN-A1, DREB2A, HsfA3, PIF4, PhyB, HSP17.6CII, rbcL, and MYB73. YUCCA2, HSP101, ERF1, and VRN-A1 showed a significant difference in gene expression between lower- and higher-temperature conditions. Overall, combining the means of the expression of various genes involved in thermosensing, vernalization, and abiotic stresses, it is possible to conclude that different sets of genes are involved in vernalization and summer depression of wheat under long term, high ambient temperature conditions.

• Molecules and Cells
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• v.41 no.9
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• pp.868-880
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• 2018

Pancreatic cancer (PC) is one of the most aggressive cancers presenting with high rates of invasion and metastasis, and unfavorable prognoses. The current study aims to investigate whether EZH2/miR-139-5p axis affects epithelial-mesenchymal transition (EMT) and lymph node metastasis (LNM) in PC, and the mechanism how EZH2 regulates miR-139-5p. Human PC and adjacent normal tissues were collected to determine expression of EZH2 and miR-139-5p, and their relationship with clinicopathological features of PC. Human PC cell line was selected, and treated with miR-139-5p mimics/inhibitors, EZH2 vector or shEZH2 in order to validate the regulation of EZH2-mediated miR-139-5p in PC cells. Dual-luciferase report gene assay and chromatin immunoprecipitation assay were employed to identify the relationship between miR-139-5p and EZH2. RT-qPCR and Western blot analysis were conducted to determine the expression of miR-139-5p, EZH2 and EMT-related markers and ZEB1/2. Tumor formation ability and in vitro cell activity were also analyzed. Highly-expressed EZH2 and poorly-expressed miR-139-5p were detected in PC tissues, and miR-139-5p and EZH2 expressions were associated with patients at Stage III/IV, with LNM and highly-differentiated tumors. EZH2 suppressed the expression of miR-139-5p through up-regulating Histone 3 Lysine 27 Trimethylation (H3K27me3). EMT, cell proliferation, migration and invasion were impeded, and tumor formation and LNM were reduced in PC cells transfected with miR-139-5p mimics and shEZH2. MiR-139-5p transcription is inhibited by EZH2 through up-regulating H3K27me3, thereby down-regulation of EZH2 and up-regulation of miR-139-5p impede EMT and LNM in PC. In addition, the EZH2/miR-139-5p axis presents as a promising therapeutic strategy for the treatment of PC.

• Molecules and Cells
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• v.44 no.9
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• pp.658-669
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• 2021

Enhancers have been conventionally perceived as cis-acting elements that provide binding sites for trans-acting factors. However, recent studies have shown that enhancers are transcribed and that these transcripts, called enhancer RNAs (eRNAs), have a regulatory function. Here, we identified putative eRNAs by profiling and determining the overlap between noncoding RNA expression loci and eRNA-associated histone marks such as H3K27ac and H3K4me1 in hepatocellular carcinoma (HCC) cell lines. Of the 132 HCC-derived noncoding RNAs, 74 overlapped with the eRNA loci defined by the FANTOM consortium, and 65 were located in the proximal regions of genes differentially expressed between normal and tumor tissues in TCGA dataset. Interestingly, knockdown of two selected putative eRNAs, THUMPD3-AS1 and LINC01572, led to downregulation of their target mRNAs and to a reduction in the proliferation and migration of HCC cells. Additionally, the expression of these two noncoding RNAs and target mRNAs was elevated in tumor samples in the TCGA dataset, and high expression was associated with poor survival of patients. Collectively, our study suggests that noncoding RNAs such as THUMPD3-AS1 and LINC01572 (i.e., putative eRNAs) can promote the transcription of genes involved in cell proliferation and differentiation and that the dysregulation of these noncoding RNAs can cause cancers such as HCC.

• Journal of Life Science
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• v.28 no.12
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• pp.1397-1405
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• 2018

Mitochondria have multiple functions in cells: providing chemical energy, storing cellular $Ca^{2+}$, generating reactive oxygen species, and regulating apoptosis. Through these functions, mitochondria are also involved in the maintenance, proliferation, and differentiation of stem/progenitor cells. In the brain, the subventricular zone (SVZ) is one of the neurogenic regions that contains neural stem cells (NSCs) throughout a lifetime. However, reports on the role of mitochondria in SVZ NSCs are scarce. Here, we show that rotenone, a complex I inhibitor of mitochondria, inhibits the proliferation and differentiation of SVZ NSCs in different ways. In proliferating NSCs, rotenone decreases mitosis as measured through phosphorylated histone H3 detection; moreover, apoptosis is not induced by rotenone at 50 nM. In differentiating NSCs, rotenone blocks neurogenesis and oligodendrogenesis while glial fibrillary acidic protein-positive astrocytes are not affected. Interestingly, in this study there were more cells in the differentiating NSCs treated with rotenone for 4-6 days than in the vehicle control group which was a different effect from the reduced number of cells in the proliferating NSCs. We examined both apoptosis and mitosis and found that rotenone decreased apoptosis as detected by staining cleaved caspase-3 but did not affect mitosis. Our results suggest that functional mitochondria are necessary in both the proliferation and differentiation of SVZ NSCs. Furthermore, mitochondria might be involved in the mitosis and apoptosis that occur during those processes.

• Molecules and Cells
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• v.43 no.4
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• pp.331-339
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• 2020

Genetic modifications in noncoding regulatory regions are likely critical to human evolution. Human-accelerated noncoding elements are highly conserved noncoding regions among vertebrates but have large differences across humans, which implies human-specific regulatory potential. In this study, we found that human-accelerated noncoding elements were frequently coupled with DNase I hypersensitive sites (DHSs), together with monomethylated and trimethylated histone H3 lysine 4, which are active regulatory markers. This coupling was particularly pronounced in fetal brains relative to adult brains, non-brain fetal tissues, and embryonic stem cells. However, fetal brain DHSs were also specifically enriched in deeply conserved sequences, implying coexistence of universal maintenance and human-specific fitness in human brain development. We assessed whether this coexisting pattern was a general one by quantitatively measuring evolutionary rates of DHSs. As a result, fetal brain DHSs showed a mixed but distinct signature of regional conservation and outlier point acceleration as compared to other DHSs. This finding suggests that brain developmental sequences are selectively constrained in general, whereas specific nucleotides are under positive selection or constraint relaxation simultaneously. Hence, we hypothesize that human- or primate-specific changes to universally conserved regulatory codes of brain development may drive the accelerated, and most likely adaptive, evolution of the regulatory network of the human brain.