• Biomolecules & Therapeutics
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• v.20 no.1
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• pp.81-88
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• 2012

Histone deacetylases (HDACs) are enzymes involved in the remodelling of chromatin, and have a key role in the epigenetic regulation of gene expression. Histone deacetylase (HDAC) inhibitors are emerging as an exciting new class of potential anti-cancer agents. In recent years, a number of structurally diverse HDAC inhibitors have been identifi ed and these HDAC inhibitors induce growth arrest, differentiation and/or apoptosis of cancer cells in vitro and in vivo. However, the underlying molecular mechanisms remain unclear. This study aimed at investigating the anti-tumor activity of various HDAC inhibitors, IN-2001, using T47D human breast cancer cells. Moreover, the possible mechanism by which HDAC inhibitors exhibit anti-tumor activity was also explored. In estrogen receptor positive T47D cells, IN-2001, HDAC inhibitor showed anti-proliferative effects in dose-and time-dependent manner. In T47D human breast cancer cells showed anti-tumor activity of IN-2001 and the growth inhibitory effects of IN-2001 were related to the cell cycle arrest and induction of apoptosis. Flow cytometry studies revealed that IN-2001 showed accumulation of cells at $G_2$/M phase. At the same time, IN-2001 treatment time-dependently increased sub-$G_1$ population, representing apoptotic cells. IN-2001-mediated cell cycle arrest was associated with induction of cdk inhibitor expression. In T47D cells, IN-2001 as well as other HDAC inhibitors treatment significantly increased $p21^{WAF1}$ and $p27^{KIP1}$ expression. In addition, thymidylate synthase, an essential enzyme for DNA replication and repair, was down-regulated by IN-2001 and other HDAC inhibitors in the T47D human breast cancer cells. In summary, IN-2001 with a higher potency than other HDAC inhibitors induced growth inhibition, cell cycle arrest, and eventual apoptosis in human breast cancer possibly through modulation of cell cycle and apoptosis regulatory proteins, such as cdk inhibitors, cyclins, and thymidylate synthase.

• Journal of Microbiology and Biotechnology
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• v.31 no.12
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• pp.1615-1623
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• 2021

Picropodophyllotoxin (PPT), an epimer of podophyllotoxin, is derived from the roots of Podophyllum hexandrum and exerts various biological effects, including anti-proliferation activity. However, the effect of PPT on colorectal cancer cells and the associated cellular mechanisms have not been studied. In the present study, we explored the anticancer activity of PPT and its underlying mechanisms in HCT116 cells. The 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used to monitor cell viability. Flow cytometry was used to evaluate cell cycle distribution, the induction of apoptosis, the level of reactive oxygen species (ROS), assess the mitochondrial membrane potential (Δψm), and multi-caspase activity. Western blot assays were performed to detect the expression of cell cycle regulatory proteins, apoptosis-related proteins, and p38 MAPK (mitogen-activated protein kinase). We found that PPT induced apoptosis, cell cycle arrest at the G1 phase, and ROS in the HCT116 cell line. In addition, PPT enhanced the phosphorylation of p38 MAPK, which regulates apoptosis and PPT-induced apoptosis. The phosphorylation of p38 MAPK was inhibited by an antioxidant agent (N-acetyl-L-cysteine, NAC) and a p38 inhibitor (SB203580). PPT induced depolarization of the mitochondrial inner membrane and caspase-dependent apoptosis, which was attenuated by exposure to Z-VAD-FMK. Overall, these data indicate that PPT induced G1 arrest and apoptosis via ROS generation and activation of the p38 MAPK signaling pathway.

• Journal of Periodontal and Implant Science
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• v.49 no.3
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• pp.138-147
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• 2019

Purpose: Several studies have shown that the oral cavity is a secondary location for Helicobacter pylori colonization and that H. pylori is associated with the severity of periodontitis. This study investigated whether H. pylori had an effect on the periodontium. We established an invasion model of a standard strain of H. pylori in human periodontal ligament fibroblasts (hPDLFs), and evaluated the effects of H. pylori on cell proliferation and cell cycle progression. Methods: Different concentrations of H. pylori were used to infect hPDLFs, with 6 hours of co-culture. The multiplicity of infection in the low- and high-concentration groups was 10:1 and 100:1, respectively. The Cell Counting Kit-8 method and Ki-67 immunofluorescence were used to detect cell proliferation. Flow cytometry, quantitative real-time polymerase chain reaction, and western blots were used to detect cell cycle progression. In the high-concentration group, the invasion of H. pylori was observed by transmission electron microscopy. Results: It was found that H. pylori invaded the fibroblasts, with cytoplasmic localization. Analyses of cell proliferation and flow cytometry showed that H. pylori inhibited the proliferation of periodontal fibroblasts by causing G2 phase arrest. The inhibition of proliferation and G2 phase arrest were more obvious in the high-concentration group. In the low-concentration group, the G2 phase regulatory factors cyclin dependent kinase 1 (CDK1) and cell division cycle 25C (Cdc25C) were upregulated, while cyclin B1 was inhibited. However, in the high-concentration group, cyclin B1 was upregulated and CDK1 was inhibited. Furthermore, the deactivated states of tyrosine phosphorylation of CDK1 (CDK1-Y15) and serine phosphorylation of Cdc25C (Cdc25C-S216) were upregulated after H. pylori infection. Conclusions: In our model, H. pylori inhibited the proliferation of hPDLFs and exerted an invasive effect, causing G2 phase arrest via the Cdc25C/CDK1/cyclin B1 signaling cascade. Its inhibitory effect on proliferation was stronger in the high-concentration group.

• Journal of the Korean Society of Food Science and Nutrition
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• v.46 no.4
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• pp.417-425
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• 2017

Cnidium monnieri (L.) Cusson is distributed in China and Korea, and the fruit of C. monnieri is used as traditional Chinese medicine to treat carbuncle and pain in female genitalia. In this study, we examined the anti-proliferation and cell cycle arrest effects of ethanol extracts from C. monnieri (CME) in AGS gastric cancer cells. Our results show that CME suppressed cell proliferation and induced release of lactate dehydrogenase (LDH) in AGS cells by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2H-tetrazolium bromide assay and LDH assay. Cell morphology was altered by CME in a dose-dependent manner. In order to identify the cell cycle arrest effects of CME, we investigated cell cycle analysis after CME treatment. In our results, CME induced cell cycle arrest at G1 phase. Protein kinase B (Akt) plays a major role in cell survival mechanisms such as growth, division, and metastasis. Akt protein regulates various downstream proteins such as glycogen synthase kinase-$3{\beta}$ (GSK-$3{\beta}$) and tumor protein p53 (p53). Expression levels of p-Akt, p-GSK-$3{\beta}$, p53, p21, cyclin E, and cyclin-dependent kinase 2 (CDK2) were determined by Western blot analysis. Protein levels of p-Akt, p-GSK-$3{\beta}$, and cyclin E were reduced while those of p53, p21, and p-CDK2 (T14/Y15) were elevated by CME. Moreover, treatment with CME, LY294002 (phosphoinositide 3-kinase/Akt inhibitor), BIO (GSK-$3{\beta}$ inhibitor), and Pifithrin-${\alpha}$ (p53 inhibitor) showed that cell cycle arrest effects were mediated through regulation of the Akt/GSK-$3{\beta}$/p53 signaling pathway. These results suggest that CME induces cell cycle arrest at G1 phase via the Akt/GSK-$3{\beta}$/p53 signaling pathway in AGS gastric cancer cells.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2021.05a
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• pp.203-204
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• 2021

Bacteria used in self-healing concrete, which arrest the crack, helps increasing the durability is well known. However, the survival and activity of the bacteria are precisely unknown. In this research, to know the bacteria's survival curve on the surface of the cement composite, bacteria's survival curve has been measured by CFU at different curing days. The survival curve of 3 days and 7 days curing does not show the significant differences in their survival tendency. However, the slope of death phase of 7 days curing was steeper than the 3 days of curing. This research was focused on the death phase but for further research, set of interval time will be reduced and observe the lag phase and exponential phase.

• Journal of Life Science
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• v.23 no.9
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• pp.1109-1117
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• 2013

Induction of G1 Arrest by Methanol Extract of Lycopus lucidus in Human Lung Adenocarcinoma A549 Cells Lycopus lucidus, a herbaceous perennial, is used as a traditional remedy in East Asia, including China and Korea. It has been reported that L. lucidus has anti-allergic effects, inhibitory effects on cholesterol acyltransferase in high glucose-induced vascular inflammation, and anti-proliferative effects in human breast cancer cells. However, the molecular mechanisms of the anti-cancer effects of L. lucidus have not yet been fully determined. In this study, we evaluated the anti-cancer effect and the mechanism of action of L. lucidus in human lung adenocarcinoma A549 cells using methanol extracts of L. lucidus (MELL). MELL treatment showed cytotoxic activity in a dose-dependent manner and induced G1 arrest in A549 cells. The induction of G1 arrest by MELL was associated with the up-regulation of phospho-CHK2 and the down-regulation of Cdc25A phosphatase. In addition, MELL treatment induced decreased expression of G1/S transition-related proteins, including CDK2, CDK4, CDK6, cyclin D1 and cyclin E. MELL also regulated the mRNA expression of CDK2 and cyclin E. On the other hand, the expression of p53 and the cyclin-dependent kinase inhibitor p21 was not induced by MELL. Collectively, these results suggest that MELL may exert an anti-cancer effect by cell cycle arrest at G1 phase through the ATM/CHK2/Cdc25A/CDK2 pathway in A549 cells.

• The Journal of Internal Korean Medicine
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• v.28 no.4
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• pp.694-708
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• 2007

Objectives : Jageum-Jung is used as an anti-cancer agent in oriental medicine, but the mechanism by which it induces cell death in cancer cells is still unclear. The purpose of this study was to investigate the effects of Jageum-Jung on apoptosis and cell cycle arrest in HepG2 hepatoma cells. Methods : Various cancer cell lines including HepG2, C6 glioma, SH-SY5Y, PANC-1, and MCF-7 cells, were used. Apoptosis was determined by DAPI nuclei staining and flow cytometry in HepG2 cells treated with various concentrations (from 25 to 200 ${\mu}g/ml$) of $H_2O$ extract of Jageum-Jung (JGJ) for 48 hrs. Expression of cell cycle arrest mediators including Rb, p53, p21, cyclin B1, cdk4, and cyclin E proteins were measured by Western blot analysis. To estimate intracellular hydrogen peroxide levels and intracellular nitric oxide levels, HepG2 cells were stained with DCFH-DA dye and DAF dye, subjected on flow cytometric analysis. Results : 1. Jageum-Jung decreased the viability of HepG2 cells in a dose-dependent manner. 2. Jageum-Jung induced the catalytic activation of caspase-3 in HepG2 cells. 3. Jageum-Jung increased the intracellular hydrogen peroxide and NO in HepG2 cells. 4. Jageum-Jung increased the expression of Rb, p53 and p21 in HepG2 cells. 5. Jageum-Jung induced the expression of cyclin B1, cdk4, and cyclin E in HepG2 cells. Conclusions : Taken together, we suggest that Jageum-Jung exhibits cytotoxic effects on HepG2 cells, causing apoptosis and cell cycle arrest. The results showed that Jageum-Jung may do so by regulating the expression of specific target molecules that promote efficient apoptotic cell death following $G_2$/M phase arrest in a dose-dependent manner.

• Journal of Life Science
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• v.19 no.1
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• pp.1-8
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• 2009

In this paper, to elucidate the further mechanisms of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced growth arrest, we investigated the effect of MNNG on cell cycle and proliferation in U937 cells, a p53-null human myeloid leukemia cell line. It was found that MNNG causes an arrest at the G2/M phase of the cell cycle and induces apoptosis, which is closely correlated to inhibition of cyclin B1 and cyelin-dependent kinase (Cdk) 2-associated kinase activities. MNNG treatment in. creased protein and mRNA levels of the Cdk inhibitor p21(WAF1/CIP1), and activated the reporter construct of a p21 promoter. By using p21 promoter deletion constructs, the MNNG-responsive element was mapped to a region between 113 and 61 relative to the transcription start site. These data indicate that in U937 cells MNNG can circumvent the loss of wild-type p53 function and induce critical downstream regulatory events leading to transcriptional activation of p21. Present results indicate that the p53-independent up-regulation of p21 by MNNG is likely responsible for the inhibition of cyclin/Cdk complex kinase activity rather than the down-regulation of cyclins and Cdks expression. These novel phenomena have not been previously described and provide important new insights into the possible biological effects of MNNG.

• Tuberculosis and Respiratory Diseases
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• v.82 no.2
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• pp.133-142
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• 2019

Background: Idiopathic pulmonary fibrosis involves irreversible alveolar destruction. Although alveolar epithelial type II cells are key functional participants within the lung parenchyma, how epithelial cells are affected upon bleomycin (BLM) exposure remains unknown. In this study, we determined whether BLM could induce cell cycle arrest via regulation of Schlafen (SLFN) family genes, a group of cell cycle regulators known to mediate growth-inhibitory responses and apoptosis in alveolar epithelial type II cells. Methods: Mouse AE II cell line MLE-12 were exposed to $1-10{\mu}g/mL$ BLM and $0.01-100{\mu}M$ baicalein (Bai), a G1/G2 cell cycle inhibitor, for 24 hours. Cell viability and levels of pro-inflammatory cytokines were analyzed by MTT and enzyme-linked immunosorbent assay, respectively. Apoptosis-related gene expression was evaluated by quantitative real-time reverse transcription-polymerase chain reaction (qRT-PCR). Cellular morphology was determined after DAPI and Hoechst 33258 staining. To verify cell cycle arrest, propidium iodide (PI) staining was performed for MLE-12 after exposure to BLM. Results: BLM decreased the proliferation of MLE-12 cells. However, it significantly increased expression levels of interleukin 6, tumor necrosis factor ${\alpha}$, and transforming growth factor ${\beta}1$. Based on Hoechst 33258 staining, BLM induced condensation of nuclear and fragmentation. Based on DAPI and PI staining, BLM significantly increased the size of nuclei and induced G2/M phase cell cycle arrest. Results of qRT-PCR analysis revealed that BLM increased mRNA levels of BAX but decreased those of Bcl2. In addition, BLM/Bai increased mRNA levels of p53, p21, SLFN1, 2, 4 of Schlafen family. Conclusion: BLM exposure affects pulmonary epithelial type II cells, resulting in decreased proliferation possibly through apoptotic and cell cycle arrest associated signaling.

• YAKHAK HOEJI
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• v.43 no.3
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• pp.378-384
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• 1999

Retinoic acid (RA) and dibutyryl cyclic AMP (dbcAMP) induce the differentiation of the multipotent embryonic carcinoma cell line, F9 cells, into parietal endoderm like cell. The F9 cells are highly proliferative doubling approximately 12 hourse. S Phase is predominant, lasting 10 hours and G2/M phase occupies most of the remaining cycle (2 hours) and G1 phase is nearly non-existent. In this study, we showed the effect of RA and dbcAMPon the cell cycle associated molecules (especially around G1 phase) during F9 cell differentiation. Differentiation of F9 cells was induced by the combined addition of RA ($10^{-7}M$) and dbcAMP (0.5mM), and cells were harvested daily up to 4 days. Flow cytometric analysis showed the prolongation of G1 phase around 30 hours after induction. Western blot analysis revealed that the amount of cyclin D1 and cdk2 were increased at day 4. However, histone H1 kinase activity of cdk2 was decreased. These data strongly suggest that RA and dbcAMP induce the growth arrest of F9 cells at G1 phase by decreasing the activity of cdk2, although they have increased the protein contents of cyclin D1 and cdk2. The reason for the discrepancy between the H1 kinase activity and protein contents are not clear yet.