• Journal of Korean Neurosurgical Society
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• v.37 no.1
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• pp.48-53
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• 2005

Objective: The purpose of this study is to elucidate in vitro responses to combined gamma knife irradiation and p53 gene transfection on human malignant glioma cell lines. Methods: Two malignant human glioma cell lines, U87MG (p53-wild type) and U373MG (p53-mutant) were transfected with an adenoviral vector containing p53 (MOI of 50) before and after applying 20Gy of gamma irradiation. Various assessments were performed, including, cell viability by MTT assay; apoptosis by annexin assay; and cell cycle by flow cytometry, for the seven groups: mock, p53 only, gamma knife (GK) only, GK after LacZ, LacZ after GK, GK after p53, p53 after GK. Results: Cell survival decreased especially, in the subgroup transfected with p53 after gamma irradiation. Apoptosis tended to increase in p53 transfected U373 MG after gamma irradiation (apoptotic rate, 38.9%). The G2-M phase cell cycle arrest markedly increased by transfecting with p53, 48 hours after gamma knife irradiation in U373 MG (G2-M phase, 90.8%). Conclusion: These results suggest that the in vitro effects of combined gamma knife irradiation and p53 gene transfection is an augmentation of apoptosis and G2-M phase cell cycle arrest, which are more exaggerated in U373 MG with p53 transfection after gamma knife irradiation.

• Molecular & Cellular Toxicology
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• v.2 no.3
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• pp.159-165
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• 2006

To determine the anticancer effect of D-amygdalin (D-mandelinitrole-${\beta}$-D-gentiobioside) in human chronic myeloid leukemia cells K562, we profiled the gene expression between amygdalin treatment and control groups. Through 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT) assay, the cytotoxicity of D-amygdalin was $57.79{\pm}1.83%$ at the concentration of 5 mg/mL for 24 h. We performed cDNA microarray analysis and compared the gene expression profiles between D-amygdalin (5 mg/mL, 24 h) treatment and control groups. Among the genes changed by D-amygdalin, we paid attention to cell cycle-related genes, and particularly cell cycle regulator genes; because arrest of cell cycle processing was ideal tactic in remedy for cancer. In our data, expressions of cyclin-dependent kinase inhibitor 1B (p27, Kip1) (CDKN1B), ataxia telangiectasia mutated (includes complementation groups A, C, and D) (ATM), cyclin-dependent kinase inhibitor 1C (p57, Kip2) (CDKN1C), and CHK1 checkpoint homolog (CHEK1, formally known as CHK1) were increased, while expressions of cyclin-dependent kinase 2 (CDK2), cell division cycle 25A (CDC25A), and cyclin E1 (CCNE1) were decreased. The pattern of these gene expressions were confirmed through RT-PCR. Our results showed that D-amygdalin might control cell cycle regulator genes and arrest S phase of cell cycle in K562 cells as the useful anticancer drug.

• Korean Journal of Environmental Biology
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• v.23 no.1
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• pp.21-26
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• 2005

Cell response to genotoxic agents is complex and involves the participation of different classes of genes including cell cycle control, DNA repair and apoptosis. In this report, we presented a approach to characterize the cellular functions associated with the altered transcript profiles of MCF-7 exposed to low-dose in vitro gamma-irradiation. We used the method of human 2.4 k cDNA microarrays containing apoptosis, cell cycle, chromatin, repair, stress and chromosome genes to analyze the differential gene expression characterization that were displayed by radiation-exposed cell, human breast carcinoma MCF-7 cell line, such as 4 Gy 4 hr, 8 Gy 4 hr, and 8 Gy 12 hr. Among these genes, 66 were up-regulated and 49 were down-regulated. Specific genes were concomitantly induced in the results. Cyclin dependent kinase 4 (Cdk4) is induced for starting the cell cycle. This regulation is required for a DNA damage­induced G1 arrest. In addition to, an apoptotic pathways gene Bcl-w was concomitantly induced. Mismatch repair protein homologue-l (hMLH1), a necessary component of DNA mismatch protein repair (MMR), in G2-M cell cycle checkpoint arrest. The present study provides new information on the molecular mechanism underlying the cell response to genotoxic stress, with relevance to basic and clinical research.

• Molecules and Cells
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• v.46 no.6
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• pp.387-398
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• 2023

Microtubule acetylation has been proposed as a marker of highly heterogeneous and aggressive triple-negative breast cancer (TNBC). The novel microtubule acetylation inhibitors GM-90257 and GM-90631 (GM compounds) cause TNBC cancer cell death but the underlying mechanisms are currently unknown. In this study, we demonstrated that GM compounds function as anti-TNBC agents through activation of the JNK/AP-1 pathway. RNA-seq and biochemical analyses of GM compound-treated cells revealed that c-Jun N-terminal kinase (JNK) and members of its downstream signaling pathway are potential targets for GM compounds. Mechanistically, JNK activation by GM compounds induced an increase in c-Jun phosphorylation and c-Fos protein levels, thereby activating the activator protein-1 (AP-1) transcription factor. Notably, direct suppression of JNK with a pharmacological inhibitor alleviated Bcl2 reduction and cell death caused by GM compounds. TNBC cell death and mitotic arrest were induced by GM compounds through AP-1 activation in vitro. These results were reproduced in vivo, validating the significance of microtubule acetylation/JNK/AP-1 axis activation in the anti-cancer activity of GM compounds. Moreover, GM compounds significantly attenuated tumor growth, metastasis, and cancer-related death in mice, demonstrating strong potential as therapeutic agents for TNBC.

• Journal of Microbiology and Biotechnology
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• v.26 no.2
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• pp.287-294
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• 2016

The effect of kaempferol (3,5,7,4-tetrahydroxyflavone), a flavonoid compound that was identified in barnyard millet (Echinochloa crus-galli var. frumentacea) grains, on G₂-checkpoint and apoptotic pathways was investigated in human acute leukemia Jurkat T cell clones stably transfected with an empty vector (J/Neo) or a Bcl-xL expression vector (J/Bcl-xL). Exposure of J/Neo cells to kaempeferol caused cytotoxicity and activation of the ATM/ATR-Chk1/Chk2 pathway, activating the phosphorylation of p53 (Ser-15), inhibitory phosphorylation of Cdc25C (Ser-216), and inactivation of cyclin-dependent kinase 1 (Cdk1), with resultant G₂-arrest of the cell cycle. Under these conditions, apoptotic events, including upregulation of Bak and PUMA levels, Bak activation, mitochondrial membrane potential (Δψm) loss, activation of caspase-9, -8, and -3, anti-poly (ADP-ribose) polymerase (PARP) cleavage, and accumulation of apoptotic sub-G₁ cells, were induced without accompanying necrosis. However, these apoptotic events, except for upregulation of Bak and PUMA levels, were completely abrogated in J/Bcl-xL cells overexpressing Bcl-xL, suggesting that the G₂-arrest and the Bcl-xL-sensitive mitochondrial apoptotic events were induced, in parallel, as downstream events of the DNA-damage-mediated G₂-checkpoint activation. Together these results demonstrate that kaempferol-mediated antitumor activity toward Jurkat T cells was attributable to G₂-checkpoint activation, which caused not only G₂-arrest of the cell cycle but also activating phosphorylation of p53 (Ser-15) and subsequent induction of mitochondria-dependent apoptotic events, including Bak and PUMA upregulation, Bak activation, Δψm loss, and caspase cascade activation.

• Proceedings of the Korean Society of Toxicology Conference
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• 2001.05a
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• pp.89-93
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• 2001

All that is presently known about the actions of 8-hydroxyguanine (8-oxoguanine; oh$^{8}$ Gua) in DNA is that it harms genetic integrity. This is even speculation based upon scattered in vitro experimental data such as the mismatch of oh$^{8}$ Gua with A in stead of C and the GC longrightarrow TA transversion observed in the DNA polymerase reaction using an oh$^{8}$ Gua containing oligonucleotide.(omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.244.1-244.1
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• 2002

Cyclooxygenase-2 ( COX-2 ) is an inducible enzyme which produces prostanoids by various stimuli. Overexpression of COX-2 in many tumor types indicates its association with tumor progression, which has been a promising target for chemoprevention and chemomodulation. We studied conc- and time-dependency of COX-2 inhibition, growth inhibition, and cell cycle arrest induced by celecoxib, a selective COX-2 inhibitor, in human non-small cell lung cancer (NSCLC) A549 cells. (omitted)

• Proceedings of the PSK Conference
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• 2002.10a
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• pp.328.1-328.1
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• 2002

A major lipid-signaling pathway in mammalian cells implicated the activation of sphingomyelinase (SMase), which hydrolyses sphingomyeline to generate ceramide and phosphocholine. Sphingomyelinase is divided into many isoform groups dependent on optimal pH, and essential cation especially magnesium in their activation. Such as acidic sphingomyelinase, neutral sphingomyelinase and alkaline sphingomyelinase. Ceramide is known as a crucial second messenger in cell responses like cell proliferation. cell cycle arrest. cellular senescence, and apoptosis. (omitted)

• Journal of Microbiology and Biotechnology
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• v.15 no.4
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• pp.694-700
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• 2005

Defects in the mitotic spindle or in the attachment of chromosomes to the spindle are believed to release an activated form of spindle checkpoint complex that inhibits APC-dependent ubiquitination and subsequently arrests the cell cycle at metaphase. When the spindle assembly is disrupted, the fission yeast mitotic arrest deficient (mad) mutants fail to arrest and rapidly lose viability. To enhance our understanding of the molecular mechanisms for the pathway of checkpoint function, the functional characterizations of Mad 1 p from Schizosaccharomyces pombe involved in this process have been carried out. Yeast two-hybrid and various deletion analyses of S. pombe Mad1 p reveal that the C terminus of Mad1p is critical for the binding of Mad2p and maintenance of Mad 1 p-Mad2p interaction. In addition, it was found. that the Mad1p region (residues 206-356) is essential for Mad1p-other checkpoint components. Mad1p truncating this region is sufficient to bind Mad2p but abolishes the checkpoint function, indicating that the checkpoint function is necessary for interaction of Mad 1 p-other checkpoint components. The possible functions of S. pombe Mad1p at the cell cycle checkpoint are discussed.

• International Journal of Oral Biology
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• v.39 no.1
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• pp.1-7
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• 2014

Neuromedin B (NMB) acts as a growth factor or a morphogen and plays a role in cancer progression. Indeed, the NMB receptor (NMB-R) is overexpressed in different types of tumors. In our current study, we investigated the involvement of NMB-R in the proliferation of oral cancer cells. Human oral squamous cell carcinoma (SCC) and human oral cancer cells, SCC-25 cells were found to be NMB-R-positive. The NMB-R antagonist PD168368 inhibited the proliferation of SCC-25 cells and reduced their colony formation capacity. We also found that PD168368 induced the cell cycle arrest and apoptosis of SCC-25 cells in a dose-/time-dependent manner. Overall, this antitumor activity of PD168368 in human oral cancer cells suggests that NMB-R is a potential target for the future prevention and treatment of human cancers.