• Journal of Life Science
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• v.27 no.10
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• pp.1104-1110
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• 2017

SET1A is a histone H3K4 methyltransferase that catalyzes di- and trimethylation of histone H3 at lysine 4 (H3K4). Mono-, di-, and trimethylations on H3K4 (H3K4me1, H3K4me2, and H3K4me3, respectively) are generally correlated with gene activation. Although H3K4 methylation is associated with the stimulation of adipogenesis of 3T3-L1 preadipocytes, it remains unknown whether SET1A plays a role in the regulation of adipogenesis of 3T3-L1 preadipocytes. Here, we investigated whether SET1A regulates 3T3-L1 preadipocytes' adipogenesis and characterized the mechanism involved in this regulation. SET1A expression increased during 3T3-L1 preadipocytes' adipogenesis. Consistent with the increased SET1A expression, the global H3K4me3 level had also increased on day 2 after the induction of adipogenesis in 3T3-L1 adipocytes. SET1A knockdown using siRNA in 3T3-L1 preadipocytes inhibited 3T3-L1 preadipocytes' adipogenesis, as assessed by Oil Red O staining and the expression of adipogenic genes, indicating that SET1A stimulates the adipogenesis of 3T3-L1 preadipocytes. SET1A knockdown inhibited the cell proliferation of 3T3-L1 cells during mitotic clonal expansion (MCE) via down-regulation of the cell cycle gene cyclin E1, as well as the DNA synthesis gene, dihydrofolate reductase. Furthermore, SET1A knockdown repressed peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) expression during the late stage of adipogenesis. These results indicate that SET1A stimulates MCE and $PPAR{\gamma}$ expression, which leads to the promotion of 3T3-L1 preadipocytes' adipogenesis.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.5
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• pp.2915-2918
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• 2013

Background: Recent studies have shown that 3-deazaneplanocin A (DZNep), a well-known histone methyltransferase inhibitor, disrupts polycomb-repressive complex 2 (PRC2), and induces apoptosis, while inhibiting proliferation and metastasis, in cancer cells, including acute myeloid leukemia, breast cancer and glioblastoma. However, little is known about effects of DZNep on ovarian cancer cells. Materials and Methods: We here therefore studied DZNep-treated A2780 ovarian cancer cells in vitro. Proliferation of ovarian cancer cells under treatment of DZNep was assessed by MTT and apoptosis by flow cytometry. Cell wound healing was applied to detect the migration. Finally, we used q-PCR to assess the migration-related gene, E-cadherin. Results: DZNep could inhibit the proliferation of A2780 and induce apoptosis Furthermore, it inhibited migration and increased the expression of E-cadherin (P<0.05). Conclusion: DZNep is a promising therapeutic agent for ovarian cancer cells, with potential to inhibite proliferation, induce apoptosis and decrease migration.

• Molecules and Cells
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• v.38 no.4
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• pp.362-372
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• 2015

Setdb1, an H3-K9 specific histone methyltransferase, is associated with transcriptional silencing of euchromatic genes through chromatin modification. Functions of Setdb1 during development have been extensively studied in embryonic and mesenchymal stem cells as well as neurogenic progenitor cells. But the role of Sedtdb1 in myogenic differentiation remains unknown. In this study, we report that Setdb1 is required for myogenic potential of C2C12 myoblast cells through maintaining the expressions of MyoD and muscle-specific genes. We find that reduced Setdb1 expression in C2C12 myoblast cells severely delayed differentiation of C2C12 myoblast cells, whereas exogenous Setdb1 expression had little effect on. Gene expression profiling analysis using oligonucleotide microarray and RNA-Seq technologies demonstrated that depletion of Setdb1 results in downregulation of MyoD as well as the components of muscle fiber in proliferating C2C12 cells. In addition, exogenous expression of MyoD reversed transcriptional repression of MyoD promoter-driven luciferase reporter by Setdb1 shRNA and rescued myogenic differentiation of C2C12 myoblast cells depleted of endogenous Setdb1. Taken together, these results provide new insights into how levels of key myogenic regulators are maintained prior to induction of differentiation.

• BMB Reports
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• v.52 no.2
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• pp.139-144
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• 2019

Breast cancer (BRC) is the most invasive cancer in women. Although the survival rate of BRC is gradually increasing due to improved screening systems, development of novel therapeutic targets for inhibition of BRC proliferation, metastasis and recurrence have been constantly needed. Thus, in this study, we identified overexpression of SETDB1 (SET Domain Bifurcated 1), a histone methyltransferase, in RNA-seq data of BRC derived from TCGA portal. In Gene Ontology (GO) analysis, cell migration-related GO terms were enriched, and we confirmed down-regulation of cell migration/invasion and alteration of EMT /MET markers after knockdown of SETDB1. Moreover, gene network analysis showed that SMAD7 expression is regulated by SETDB1 levels, indicating that up-regulation of SMAD7 by SETDB1 knockdown inhibited BRC metastasis. Therefore, development of SETDB1 inhibitors and functional studies may help develop more effective clinical guidelines for BRC treatment.

• BMB Reports
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• v.55 no.11
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• pp.541-546
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• 2022

The repair of DNA double-strand breaks (DSBs) by homologous recombination (HR) is crucial for maintaining genomic integrity and is involved in numerous fundamental biological processes. Post-translational modifications by proteins play an important role in regulating DNA repair. Here, we report that the methyltransferase SET7 regulates HR-mediated DSB repair by methylating TIP60, a histone acetyltransferase and tumor suppressor involved in gene expression and protein stability. We show that SET7 targets TIP60 for methylation at K137, which facilitates DSB repair by promoting HR and determines cell viability against DNA damage. Interestingly, TIP60 demethylation is catalyzed by LSD1, which affects HR efficiency. Taken together, our findings reveal the importance of TIP60 methylation status by SET7 and LSD1 in the DSB repair pathway.

• Korean Journal of Microbiology
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• v.52 no.4
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• pp.487-494
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• 2016

In Saccharomyces cerevisiae, Paf1 complex consists of five proteins, and they are structurally and functionally well conserved in yeast, fruit fly, plants, and human. With binding to RNA polymerase II from transcription start site to termination site, Paf1 complex functions as a platform for recruiting many types of transcription factors to RNA polymerase II. Paf1 complex contributes to H2B ubiquitination and indirectly influences on H3K4 di- and tri-methylation by histone crosstalk. But the individual effects of five components in Paf1 complex on these two histone modifications including H2B ubiquitination and H3K4 methylation largely remained to be identified. In this study, we constructed the single-gene knockout mutants of each Paf1 complex component and observed H3K4 mono-, di-, and trimethylation as well as H2B ubiquitination in these mutants. Interestingly, in each ${\Delta}paf1$, ${\Delta}rtf1$, and ${\Delta}ctr9$ strain, we observed the dramatic defect in H3K4 monomethylation, which is independent of H2B ubiquitination, as well as H3K4 di- and trimethylation. However, the protein level of Set1, which is methyltransferase for H3K4, was not changed in these mutants. This suggests that Paf1 complex may directly influence on H3K4 methylation by directly regulating the activity of Set1 or the stability of Set1 complex in an H2B ubiquitination independent manner.

• Reproductive and Developmental Biology
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• v.37 no.4
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• pp.269-279
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• 2013

Low efficiency of somatic cell nuclear transfer (SCNT) is attributed to incomplete reprogramming of transfered nuclei into oocytes. Trichostatin A (TSA), histone deacetylase inhibitor and 5-aza-2'deoxycytidine (5-aza-dC), DNA methylation inhibitor has been used to enhance nuclear reprogramming following SCNT. However, it was not known molecular mechanism by which TSA and 5-aza-dC improve preimplantation embryo and fetal development following SCNT. The present study investigates embryo viability and gene expression of cloned porcine preimplantation embryos in the presence and absence of TSA and 5-aza-dC as compared to embryos produced by parthenogenetic activation. Our results indicated that TSA treatment significantly improved development. However 5-aza-dC did not improve development. Presence of TSA and 5-aza-dC significantly improved total cell number, and also decreased the apoptotic and autophagic index. Three apoptotic-related genes, Bak, Bcl-xL, and Caspase 3 (Casp3), and three autophagic-related genes, ATG6, ATG8, and lysosomal-associated membrane protein 2 (LAMP2), were measured by real time RT-PCR. TSA and 5-aza-dC treatment resulted in high expression of anti-apoptotic gene Bcl-xL and low pro-apoptotic gene Bak expression compared to untreated NT embryos or parthenotes. Furthermore, LC3 protein expression was lower in NT-TSA and NT-5-aza-dC embryos than those of NT and parthenotes. In addition, TSA and 5-aza-dC treated embryos displayed a global acetylated histone H3 at lysine 9 and methylated DNA H3 at lysine 9 profile similar to the parthenogenetic blastocysts. Finally, we determined that several DNA methyltransferase genes Dnmt1, Dnmt3a and Dnmt3b. NT blastocysts showed higher levels Dnmt1 than those of the TSA and 5-aza-dC blastocysts. Dnmt3a is lower in 5-aza-dC than NT, NTTSA and parthenotes. However, Dnmt3b is higher in 5-aza-dC than NT and NTTSA. These results suggest that TSA and 5-aza-dC positively regulates nuclear reprogramming which result in modulation of apoptosis and autophagy related gene expression and then reduce apoptosis and autophagy. In addition, TSA and 5-aza-dC affects the acetylated and methylated status of the H3K9.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.47 no.2
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• pp.107-121
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• 2021

Skin hypopigmentation, which is observed in albinism or vitiligo, occurs when melanin synthesis is decreased by genetic, epigenetic, and other factors. To identify drug candidates that can promote melanin synthesis in cells, we screened an epigenetic modulator library consisting of 141 cell-permeable, small molecule drugs. B16/F10 murine melanoma cells were treated with each drug at 0.1 𝜇M and melanin synthesis and cell viability were subsequently monitored. As a result, (-)-neplanocin A, 3-deazaneplanocin A (DZNep), and DZNep hydrochloride were found to increase cellular melanin synthesis without causing cytotoxicity. Because these three structurally related drugs exhibited similar dose-dependent effects on melanin synthesis and cell viability, DZNep was selected as a representative drug for additional experiments. DZNep increased intracellular melanin content and tyrosinase (TYR) activity. DZNep also induced the expression of TYR, tyrosinase-related protein 1 (TYRP1), and dopachrome tautomerase (DCT) at the mRNA and protein levels. DZNep also induced the mRNA and protein expression of microphthalmia-associated transcription factor (MITF), a key regulator of melanin synthesis. DZNep is a specific inhibitor of S-adenosylhomocysteine hydrolase and it caused the accumulation of S-adenosylhomocysteine that inhibits histone methyltransferases in cells. This study suggests that melanogenesis can be modulated by targeting S-adenosylhomocysteine hydrolase in certain cellular contexts.

• Biomolecules & Therapeutics
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• v.26 no.6
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• pp.591-598
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• 2018

Epigenetic silencing is considered to be a major mechanism for loss of activity in tumor suppressors. Reversal of epigenetic silencing by using inhibitors of DNA methyltransferase (DNMT) or histone deacetylases (HDACs) such as 5-Aza-CdR and FK228 has shown to enhance cytotoxic activities of several anticancer agents. This study aims to assess the combinatorial effects of genesilencing reversal agents (5-Aza-CdR and FK228) and oxaliplatin in gastric cancer cells, i.e., Epstein-Barr virus (EBV)-negative SNU-638 and EBV-positive SNU-719 cells. The doublet combinatorial treatment of 5-Aza-CdR and FK228 exhibited synergistic effects in both cell lines, and this was further corroborated by Zta expression induction in SNU-719 cells. Three drug combinations as 5-Aza-CdR/FK228 followed by oxaliplatin, however, resulted in antagonistic effects in both cell lines. Simultaneous treatment with FK228 and oxaliplatin induced synergistic and additive effects in SNU-638 and SNU-719 cells, respectively. Three drug combinations as 5-Aza-CdR prior to FK228/oxaliplatin, however, again resulted in antagonistic effects in both cell lines. This work demonstrated that efficacy of doublet synergistic combination using DNMT or HDACs inhibitors can be compromised by adding the third drug in pre- or post-treatment approach in gastric cancer cells. This implies that the development of clinical trial protocols for triplet combinations using gene-silencing reversal agents should be carefully evaluated in light of their potential antagonistic effects.

• YAKHAK HOEJI
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• v.35 no.6
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• pp.473-482
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• 1991

Protein methylase II (S-adenosyl-L-methionine:protein carboxyl-O-methyltransferase; EC 2.1.1.24., PM II) was purified from chicken pancreas by subcellular fractionation, DEAE-cellulose chromatography, QAE-Sephadex A-50 chromatography, Sephadex G-75 chromatography, and Sephadex G-75 rechromatography. The purified PM II gave a single band upon polyarcrylamide gel electrophoresis both in the presence of SDS and in Tris glycine buffer without SDS. The pI value of purified PM II was identified as 5.7 on isoelectric focusing gel. Properties and activities of PM II were studied and the following results were obtained. 1) PM II from chicken pancreas was purified approximately 221-fold with a yield of 1.3%. 2) The purified PM II appear constituted of a single polypeptide chain of a molecular weight 46,800 daltons. 3) Hemoglobin exhibited the highest of methyl-accepting activity among the substrates tested. 4) The purified PM II has a $K_m$ of $4.67{\times}10^{-6}M$ and a $V_{max}$ of 37.5 pmoles of $methyl-^{14}C/min./mg$ enzyme for $SAM^{-14}CH_3$ as methyl donor in the presence of histone type II-As. 5) It is found that S-adenosyl-L-homocysteine is a competitive inhibitor for PM II with $K_i$ value of $3.23{\times}10^{-5}M$.