• YAKHAK HOEJI
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• v.49 no.6
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• pp.511-517
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• 2005

Low sensitivity to anticancer drugs such as 5-fluorouracil (5-FU) has been associated with decreased expression of genes involved in cell proliferation, apoptosis and metastasis. Recently, it has been shown that the expression levels of some of these genes are reduced by transcription inhibition due to epigenetic silencing on CpG islands. Therefore, epigenetic therapy has been proposed, where epigenetic silencing is repressed with DNA methyltransferase (DNMT) inhibitors and histone deacetylase (HDAC) inhibitors alone or in combination with other chemotherapeutic agents. The aim of our study was to evaluate the combination effect of 5-FU and its association with the status of epigenetic silencing using methylation-specific PCR of $p14^{ARF}$ when given with S-aza-2'-deoxycytidine (5-aza-dC), a DNMT inhibitor and depsipeptide, an HDAC inhibitor in DLD-1 human colorectal cancer cells. The combination of 5-aza-dC with depsipeptide showed a synergism and induced unmethylation of $p14^{ARF}$. However, triplet combination of 5-aza-dc/depsipeptide and 5-FU resulted in antagonistic effects and abrogated unmethylation of $p14^{ARF}$. These results suggest that unfavorable interaction of 5-aza-dC/depsipeptide with 5-FU in DLD-1 cells may be related with the failure in repression of epigenetic silencing, which warrants further investigation.

• International Journal of Oral Biology
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• v.35 no.4
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• pp.209-214
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• 2010

Cells that have endogenous multipotent properties can be used as a starting source for the generation of induced pluripotent cells (iPSC). In addition, small molecules associated with epigenetic reprogramming are also widely used to enhance the multi- or pluripotency of such cells. Skinderived precursor cells (SKPs) are multipotent, sphereforming and embryonic neural crest-related precursor cells. These cells can be isolated from a juvenile or adult mammalian dermis. SKPs are also an efficient starting cell source for reprogramming and the generation of iPSCs because of the high expression levels of Sox2 and Klf4 in these cells as well as their endogenous multipotency. In this study, valproic acid (VPA), a histone deacetylase (HDAC) inhibitor, was tested in the generation of iPSCs as a potential enhancer of the reprogramming potential of SKPs. SKPs were isolated from the back skins of 5-6 week old C57BL/6 X DBA/2 F1 mice. After passage 3, the SKPs was treated with 2 mM of VPA and the quantitative real time RT-PCR was performed to quantify the expression of Oct4 and Klf4 (pluripotency specific genes), and Snai2 and Ngfr (neural crest specific genes). The results show that Oct4 and Klf4 expression was decreased by VPA treatment. However, there were no significant changes in neural crest specific gene expression following VPA treatment. Hence, although VPA is one of the most potent of the HDAC inhibitors, it does not enhance the reprogramming of multipotent skin precursor cells in mice.

• KSBB Journal
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• v.30 no.1
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• pp.44-51
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• 2015

Chinese hamster ovary (CHO) cells are the most widely used mammalian host for the commercial production of recombinant proteins. However, they show relatively low yields of recombinant proteins in comparison with microbial cells. Various strategies have been tried to overcome this drawback. The acetyl moieties are attached to the N-terminus of histone by histone acetyltransferase (HAT) while histone deacetylase (HDAC) removes histone-bound acetyl groups. HDAC inhibitor (HDACi), such as sodium butyrate, sodium propionate and valproic acid, can enhance specific productivity of CHO cells. Human albumin-erythropoietin (Alb-EPO) is a novel 105 kDa protein comprising recombinant human EPO fused to human albumin. In this study, we examined the effects of HDACi on the production of Alb-EPO in CHO cells with various concentrations in the range of 0-1 mM. The results showed that sodium butyrate was found to be the best HDACi for enhancing productivity. It enhanced not only the production of Alb-EPO but also the apoptosis of recombinant CHO cells.

• Journal of Korean Neurosurgical Society
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• v.53 no.6
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• pp.337-341
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• 2013

Objective : After spinal cord injury (SCI), functional and structural reorganization occurs at multiple levels of brain including motor cortex. However, the underlying mechanism still remains unclear. The current study was performed to investigate the alterations in the expression of the main regulators of neuronal development, survival and death, in the brain following thoracic contusive SCI in a mouse model. Methods : Eight-week-old female imprinting control region mice (n=60; 30-35 g) were used in this study. We analyzed the expression levels of regulators such as brain-derived neurotrophic factor (BDNF), glial cell line-derived neurotrophic factor (GDNF), nerve growth factor (NGF) and histone deacetylase (HDAC) 1 in the brain following thoracic contusive SCI. Results : The expression of BDNF levels were elevated significantly compared with control group at 2 weeks after injury (p<0.05). The expression of NGF levels were elevated at 2, 4 weeks compared with control group, but these difference were not significant (p>0.05). The GDNF levels were elevated at 2 week compared with control group, but these differences were not significant (p>0.05). The difference of HDAC1 levels were not significant at 2, 4 and 8 weeks compared with control group (p>0.05). Conclusion : These results demonstrate that the upregulation of BDNF may play on important role in brain reorganization after SCI.

• BMB Reports
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• v.54 no.10
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• pp.534-539
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• 2021

IL-10⁺ regulatory B (Breg) cells play a vital role in regulating the immune responses in experimental autoimmune encephalomyelitis, colitis, and contact hypersensitivity (CHS). Several stimulants such as lipopolysaccharide (LPS), CD40 ligand, and IL-21 spur the activation and maturation of IL-10⁺ Breg cells, while the epigenetic mechanism for the IL-10 expression remains largely unknown. It is well accepted that the histone acetylation/deacetylation is an important mechanism that regulates the expression of IL-10. We found that entinostat, an HDAC inhibitor, stimulated the induction of IL-10⁺ Breg cells by LPS in vitro and the formation of IL-10⁺ Breg cells to suppress CHS in vivo. We further demonstrated that entinostat inhibited HDAC1 from binding to the proximal region of the IL-10 expression promoter in splenic B cells, followed by an increase in the binding of NF-κB p65, eventually enhancing the expression of IL-10 in Breg cells.

• BMB Reports
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• v.55 no.7
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• pp.348-353
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• 2022

Gastrointestinal cancer is associated with a high mortality rate. Here, we report that the splice variant of NRP/B contributes to tumorigenic activity in highly malignant gastric cancer through dissociation from the tumor repressor, HDAC5. NRP/B mRNA expression is significantly higher in the human gastric cancer tissues than in the normal tissues. Further, high levels of both the NRP/B splice variant and Lgr5, but not the full-length protein, are found in highly tumorigenic gastric tumor cells, but not in non-tumorigenic cells. The loss of NRP/B markedly inhibits cell migration and invasion, which reduces tumor formation in vivo. Importantly, the inhibition of alternative splicing increases the levels of NRP/B-1 mRNA and protein in AGS cells. The ectopic expression of full-length NRP/B exhibits tumor-suppressive activity, whereas NRP/B-2 induces the noninvasive human gastric cancer cells tumorigenesis. The splice variant NRP/B-2 which loses the capacity to interact with tumor repressors promoted oncogenic activity, suggesting that the BTB/POZ domain in the N-terminus has a crucial role in the suppression of gastric cancer. Therefore, the regulation of alternative splicing of the NRP/B gene is a potential novel target for the treatment of gastrointestinal cancer.

• Nutrition Research and Practice
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• v.17 no.1
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• pp.164-173
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• 2023

BACKGROUND/OBJECTIVES: Hyperglycemia is a major cause of diabetes and diabetesrelated diseases. Sodium butyrate (NaB) is a short-chain fatty acid derivative that produces dietary fiber by anaerobic bacterial fermentation in the large intestine and occurs in foods, such as Parmesan cheese and butter. Butyrate has been shown to prevent obesity, improve insulin sensitivity, and ameliorate dyslipidemia in diet-induced obese mice. Therefore, this study examined the effects and mechanism of NaB on the secretion of inflammatory cytokines induced by high glucose (HG) in THP-1 cells. MATERIALS/METHODS: THP-1 cells were used as an in vitro model for HG-induced inflammation. The cells were cultured under normal glycemic or hyperglycemic conditions with or without NaB (0-25 μM). Western blotting and quantitative polymerase chain reaction were used to evaluate the protein and mRNA levels of nuclear factor-κB (NF-κB), interleukin-6, tumor necrosis factor-α, acetylated p65, acetyl CREB-binding protein/p300 (CBP/p300), and p300 using THP-1 cells. Histone acetyltransferase (HAT), histone deacetylase (HDAC), and pro-inflammatory cytokine secretion activity were analyzed using an enzyme-linked immunosorbent assay. RESULTS: HG significantly upregulated histone acetylation, acetylation levels of p300, NF-κB activation, and inflammatory cytokine release in THP-1 cells. Conversely, the NaB treatment reduced cytokine release and NF-κB activation in HG-treated cells. It also significantly reduced p65 acetylation, CBP/p300 HAT activity, and CBP/p300 gene expression. In addition, NaB decreased the interaction of p300 in acetylated NF-κB and TNF-α. CONCLUSIONS: These results suggest that NaB suppresses HG-induced inflammatory cytokine production through HAT/HDAC regulation in monocytes. NaB has the potential for preventing and treating diabetes and its related complications.

• Journal of Genetic Medicine
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• v.19 no.2
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• pp.85-93
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• 2022

Purpose: Cornelia de Lange syndrome (CdLS) is a rare genetically heterogeneous disorder caused by genetic variants of the cohesin complex. However, the diverse genetic etiologies and their phenotypic correlations in Korean patients with CdLS are still largely unknown. Hence, this study aimed to clarify the clinical characteristics and genetic background of Korean patients with CdLS. Materials and Methods: The medical records of 15 unrelated patients (3 males and 12 females) genetically confirmed to have CdLS were retrospectively reviewed. All individuals were diagnosed with CdLS using target gene analysis, whole-exome sequencing, and/or chromosomal microarray analysis. The clinical score (CS) was calculated to assess disease severity. Results: The median age at diagnosis was 1.7 (range, 0.0-11.8) years, and median follow-up duration was 3.8 (range, 0.4-11.7) years. Eight (53.3%) patients showed classic phenotypes of CdLS, two (13.3%) showed non-classic phenotypes, and five (33.3%) had other phenotypes sharing limited signs of CdLS. Fifteen causative variants were identified: NIPBL in five (33.3%, including 3 males), SMC1A in three (20.0%), SMC3 in three (20.0%), and HDAC8 in four (26.7%) patients. The CS was significantly higher in the NIPBL group than in the non-NIPBL group (14.2±1.3 vs. 8.7±2.9, P<0.001). Conclusion: We identified the clinical and genetic heterogeneity of CdLS in Korean patients. Patients with variants of NIPBL had a more distinctive phenotype than those carrying variants of other cohesin complex genes (SMC1A, SMC3, and HDAC8). However, further studies are warranted to understand the pathogenesis of CdLS as a cohesinopathy and its genotype-phenotype correlations.

• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.115-122
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• 2024

Heat shock protein (HSP) 90 is expressed in most living organisms, and several client proteins of HSP90 are necessary for cancer cell survival and growth. Previously, we found that HSP90 was cleaved by histone deacetylase (HDAC) inhibitors and proteasome inhibitors, and the cleavage of HSP90 contributes to their cytotoxicity in K562 leukemia cells. In this study, we first established mouse xenograft models with K562 cells expressing the wild-type or cleavage-resistant mutant HSP90β and found that the suppression of tumor growth by the HDAC inhibitor suberoylanilide hydroxamic acid (SAHA) was interrupted by the mutation inhibiting the HSP90 cleavage in vivo. Next, we investigated the possible function of thioredoxin interacting protein (TXNIP) in the HSP90 cleavage induced by SAHA. TXNIP is a negative regulator for thioredoxin, an antioxidant protein. SAHA transcriptionally induced the expression of TXNIP in K562 cells. HSP90 cleavage was induced by SAHA also in the thymocytes of normal mice and suppressed by an anti-oxidant and pan-caspase inhibitor. When the thymocytes from the TXNIP knockout mice and their wild-type littermate control mice were treated with SAHA, the HSP90 cleavage was detected in the thymocytes of the littermate controls but suppressed in those of the TXNIP knockout mice suggesting the requirement of TXNIP for HSP90 cleavage. We additionally found that HSP90 cleavage was induced by actinomycin D, β-mercaptoethanol, and p38 MAPK inhibitor PD169316 suggesting its prevalence. Taken together, we suggest that HSP90 cleavage occurs also in vivo and contributes to the anti-cancer activity of various drugs in a TXNIP-dependent manner.

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.323.3-324
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• 2002

Histone deacetylases (HDAC) activity is associated generally with transcriptional repression. We have reported previously that apicidin. a histione deacetylase inhibitor. inhibited the proliferation of tumor cells via induction of p21 WAF/C1P1. We extended our study to identify the effect of apicidin on the expression of other cell cycle regulatory protein. such as cyclin E. a critical regulator of the transition from G1 into S phase. (omitted)