• BMB Reports
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• v.47 no.10
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• pp.575-580
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• 2014

In this study, we investigate whether arsenite-induced DNA damage leads to p53-dependent premature senescence using human glioblastoma cells with p53-wild type (U87MG-neo) and p53 deficient (U87MG-E6). A dose dependent relationship between arsenite and reduced cell growth is demonstrated, as well as induced ${\gamma}H2AX$ foci formation in both U87MG-neo and U87MG-E6 cells at low concentrations of arsenite. Senescence was induced by arsenite with senescence-associated ${\beta}$-galactosidase staining. Dimethyl- and trimethyl-lysine 9 of histone H3 (H3DMK9 and H3TMK9) foci formation was accompanied by p21 accumulation only in U87MG-neo but not in U87MG-E6 cells. This suggests that arsenite induces premature senescence as a result of DNA damage with heterochromatin forming through a p53/p21 dependent pathway. p21 and p53 siRNA consistently decreased H3TMK9 foci formation in U87M G-neo but not in U87MG-E6 cells after arsenite treatment. Taken together, arsenite reduces cell growth independently of p53 and induces premature senescence via p53/p21-dependent pathway following DNA damage.

• BMB Reports
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• v.51 no.9
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• pp.450-455
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• 2018

Tamoxifen (TAM) is commonly used to treat estrogen receptor (ER)-positive breast cancer. Despite the remarkable benefits, resistance to TAM presents a serious therapeutic challenge. Since several HOX transcription factors have been proposed as strong candidates in the development of resistance to TAM therapy in breast cancer, we generated an in vitro model of acquired TAM resistance using ER-positive MCF7 breast cancer cells (MCF7-TAMR), and analyzed the expression pattern and epigenetic states of HOX genes. HOXB cluster genes were uniquely up-regulated in MCF7-TAMR cells. Survival analysis of in slico data showed the correlation of high expression of HOXB genes with poor response to TAM in ER-positive breast cancer patients treated with TAM. Gain- and loss-of-function experiments showed that the overexpression of multi HOXB genes in MCF7 renders cancer cells more resistant to TAM, whereas the knockdown restores TAM sensitivity. Furthermore, activation of HOXB genes in MCF7-TAMR was associated with histone modifications, particularly the gain of H3K9ac. These findings imply that the activation of HOXB genes mediate the development of TAM resistance, and represent a target for development of new strategies to prevent or reverse TAM resistance.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.4
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• pp.1395-1399
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• 2012

Background: Histone deacetylase (HDAC) inhibitors have been reported to induce cell growth arrest, apoptosis and differentiation of tumor cells. The present study aimed to examine the effects of trichostatin A (TSA), one such inhibitor, on the cell cycle, apoptosis and invasiveness of osteosarcoma cells. Methods: MG-63 cells were treated with TSA at various concentrations. Then, cell growth and apoptosis were determined by 3-(4, 5-dimethyl-2-thiazolyl)-2H-tetrazolium bromide (MTT) and TUNEL assays, respectively; cell cycling was assessed by flow cytometry; invasion assays were performed with the transwell Boyden Chamber system. Results: MTT assays revealed that TSA significantly inhibited the growth of MG-63 cells in a concentration and time dependent manner. TSA treated cells demonstrated morphological changes indicative of apoptosis and TUNEL assays revealed increased apoptosis of MG-63 cells after TSA treatment. Flow cytometry showed that TSA arrested the cell cycle in G1/G2 phase and annexin V positive apoptotic cells increased markedly. In addition, the invasiveness of MG-63 cells was inhibited by TSA in a concentration dependent manner. Conclusion: Our findings demonstrate that TSA inhibits the proliferation, induces apoptosis and inhibits invasiveness of osteosarcoma cells in vitro. HDAC inhibitors may thus have promise to become new therapeutic agents against osteosarcoma.

• Biomolecules & Therapeutics
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• v.23 no.5
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• pp.434-441
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• 2015

Histone deacetylase (HDAC) inhibitors are considered novel agents for cancer chemotherapy. We previously investigated MHY219, a new HDAC inhibitor, and its potent anticancer activity in human prostate cancer cells. In the present study, we evaluated MHY219 molecular mechanisms involved in the regulation of prostate cancer cell migration. Similar to suberanilohydroxamic acid (SAHA), MHY219 inhibited HDAC1 enzyme activity in a dose-dependent manner. MHY219 cytotoxicity was higher in LNCaP ($IC_{50}=0.67{\mu}M$) than in DU145 cells ($IC_{50}=1.10{\mu}M$) and PC3 cells ($IC_{50}=5.60{\mu}M$) after 48 h of treatment. MHY219 significantly inhibited the HDAC1 protein levels in LNCaP and DU145 cells at high concentrations. However, inhibitory effects of MHY219 on HDAC proteins levels varied based on the cell type. MHY219 significantly inhibited LNCaP and DU145 cells migration by down-regulation of matrix metalloprotease-1 (MMP-1) and MMP-2 and induction of tissue inhibitor of metalloproteinases-1 (TIMP-1). These results suggest that MHY219 may potentially be used as an anticancer agent to block cancer cell migration through the repression of MMP-1 and MMP-2, which is related to the reduction of HDAC1.

• Molecules and Cells
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• v.41 no.5
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• pp.444-453
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• 2018

Aberrations in histone modifications are being studied in mixed-lineage leukemia (MLL)-AF9-driven acute myeloid leukemia (AML). In this study, we focused on the regulation of the differentiation of the MLL-AF9 type AML cell line THP-1. We observed that, upon phorbol 12-myristate 13-acetate (PMA) treatment, THP-1 cells differentiated into monocytes by down-regulating Aurora kinase A (AURKA), resulting in a reduction in H3S10 phosphorylation. We revealed that the AURKA inhibitor alisertib accelerates the expression of the H3K27 demethylase KDM6B, thereby dissociating AURKA and YY1 from the KDM6B promoter region. Using Flow cytometry, we found that alisertib induces THP-1 differentiation into monocytes. Furthermore, we found that treatment with the KDM6B inhibitor GSK-J4 perturbed the PMA-mediated differentiation of THP-1 cells. Thus, we discovered the mechanism of AURKA-KDM6B signaling that controls the differentiation of THP-1 cells, which has implications for biotherapy for leukemia.

• Journal of Life Science
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• v.30 no.12
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• pp.1092-1100
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• 2020

The six-transmembrane epithelial antigen of prostate 4 (Steap4) is a metalloreductase that plays a role in intracellular iron and cupper homeostasis, inflammatory response, and glucose and lipid metabolism. Previously, Steap4 has been reported to stimulate adipocyte differentiation; however, the underlying mechanisms of this action remain unexplored. In the present study, we investigated the molecular mechanisms involved in Steap4-induced adipocyte differentiation using 3T3-L1 cells, immortalized brown adipocyte (iBA) cells, and mouse embryonic fibroblast C3H10T1/2 cells. The knockdown of Steap4 using adenovirus-containing shRNA attenuated mitotic clonal expansion (MCE), as evidenced by the impaired proliferation of 3T3-L1 cells, iBA cells, and C3H10T1/2 cells within 48 hr after adding the differentiation medium. Steap4 knockdown downregulated G1/S phase transition-related cell cycle regulators (including cyclin A and cyclin D) and upregulated cell cycle inhibitors (including p21 and p27). Furthermore, Steap4 knockdown inhibited the phosphorylation of p38 mitogen-activated protein kinase, extracellular signal-regulated kinase, and Akt. Moreover, Steap4 knockdown repressed the expression of early adipogenic activators, such as CCAAT-enhancer-binding protein β (C/EBPβ) and Kruppel-like factor family factor 4 (KLF4). On the other hand, Steap4 knockdown stimulated the expression of adipogenic inhibitors, including KLF2, KLF3, and GATA2. The overexpression of Steap4 using an adenovirus removed the repressive histone marks H3K9me2 and H3K9me3 on the promoter of C/EBPβ. These results indicate that Stepa4 stimulates adipocyte differentiation through the induction of MCE and the modulation of early adipogenic transcription factors, including C/EBPβ, during the early phase of adipocyte differentiation.

• YAKHAK HOEJI
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• v.48 no.6
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• pp.335-344
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• 2004

Interleukin-2 (IL-2), a glycoprotein mainly secreted by CD4+ T helper Iymphocytes, has been developed to use recombinant cytokine to augment the immune response against cancer since IL-2 not only stimulates T Iymphocytes but also enhances natural killer (NK) cell activity. In order to evaluate the immunological safety of recombinant mouse IL-2 (rmIL-2) in cancer therapy, renal cell carcinoma was established in the flank by s.c. injection of renca cell line. Tumor-bearing BALB/c mice were treated with I.p. injections with $2{\times}10^5$ Lu rmIL-2. Even though the tumor size was diminished, there were not significant recovery of body and relative lymphoid organ weights including thymic atrophy in rmIL-2 immunotherapy. Distribution ratios of T cell subsets in thymus were analysed using flow cytometry. Without regard to dosage of rmIL-2, the ratio of CD3+CD4-CD8- T cells was increased in accordance with survival of solid tumor but that of CD4+CD8+ T cells was decreased dramatically. Emergence of autoantibodies (ANA, anti-dsDNA, and anti-histone) in blood was measured after rmIL-2 treatment. The results showed that the levels of ANA and anti-dsDNA did not significantly changed, but the level of anti-histone was increased significantly owing to rmIL-2 therapy. These results indicate rmIL-2 immunotherapy is to induce the autoimmune potential, and the anti-histone measurement as a biomarker of autoimmunity is useful in cancer immunotherapy.

• Biomolecules & Therapeutics
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• v.17 no.1
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• pp.12-16
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• 2009

One of the WHSC1/MMSET/NSD2 variant RE-IIBP is a histone H3-K27 methyltransferase with transcriptional repression activity. Overexpression of RE-IIBP in various types of leukemia suggests it's role in leukemogenesis. Here we identify two proteins, KRAB zinc finger protein ZNF 350 and enolase-1 as RE-IIBP interacting proteins by yeast two-hybrid screening and confirmed direct interaction in vivo and in vitro. Both proteins have been known for their role in transcriptional repression. Reporter assays using transient transfection demonstrated that both ZNF 350 and enolase-1 proteins synergistically repressed transcription with RE-IIBP, respectively. These results indicate both proteins have roles in RE-IIBP mediated transcriptional repression by involving co-repressor complex.

• Mycobiology
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• v.48 no.5
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• pp.418-422
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• 2020

In 2016, a cercosporoid fungus was found from leaf spot symptoms on melon in Korea. The fungus isolated from the plant was identified based on morphological characteristics and sequence analyses of five genes (ITS rDNA, translation elongation factor 1-α, actin, calmodulin, and histone H3). The fungal isolate was found to be pathogenic to melon. The results confirm that the fungus associated with leaf spot on melon was Cercospora cf. flagellaris. This is the first report of Cercospora cf. flagellaris causing Cercospora leaf spot on melon in Korea.

• Journal of Ginseng Research
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• v.46 no.3
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• pp.481-488
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• 2022

Background: Although the tumor-suppressive effects of ginsenosides in cell cycle have been well established, their pharmacological properties in mitosis have not been clarified yet. The chromosomal instability resulting from dysregulated mitotic processes is usually increased in cancer. In this study, we aimed to investigate the anticancer effects of ginsenoside Rg1 on mitotic progression in cancer. Materials and methods: Cancer cells were treated with ginsenoside Rg1 and their morphology and intensity of different protein were analyzed using immunofluorescence microscopy. The level of proteins in chromosomes was compared through chromosomal fractionation and Western blot analyses. The location and intensity of proteins in the chromosome were confirmed through immunostaining of mitotic chromosome after spreading. The colony formation assays were conducted using various cancer cell lines. Results: Ginsenoside Rg1 reduced cancer cell proliferation in some cancers through inducing mitotic arrest. Mechanistically, it inhibits the phosphorylation of histone H3 Thr3 (H3T3ph) mediated by Haspin kinase and concomitant recruitment of chromosomal passenger complex (CPC) to the centromere. Depletion of Aurora B at the centromere led to abnormal centromere integrity and spindle dynamics, thereby causing mitotic defects, such as increase in the width of the metaphase plate and spindle instability, resulting in delayed mitotic progression and cancer cell proliferation. Conclusion: Ginsenoside Rg1 reduces the level of Aurora B at the centromere via perturbing Haspin kinase activity and concurrent H3T3ph. Therefore, ginsenoside Rg1 suppresses cancer cell proliferation through impeding mitotic processes, such as chromosome alignment and spindle dynamics, upon depletion of Aurora B from the centromere.