• The Korean Journal of Physiology and Pharmacology
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• v.11 no.5
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• pp.163-169
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• 2007

The neurotoxicity of amyloid $\beta(A\beta)$ is associated with an increased production of reactive oxygen species and apoptosis, and it has been implicated in the development of Alzheimer's disease. While(-)-epigallocatechin-3-gallate(EGCG) suppresses $A\beta$-induced apoptosis, the mechanisms underlying this process have yet to be completely clarified. This study was designed to investigate whether EGCG plays a neuroprotective role by activating cell survival system such as protein kinase C(PKC), extracellular-signal-related kinase(ERK), c-Jun N-terminal kinase(JNK), and anti-apoptotic and pro-apoptotic genes in SH-SY5Y human neuroblastoma cells. One ${\mu}M\;A{\beta}_{1-42}$ decreased cell viability, which was correlated with increased DNA fragmentation evidenced by DAPI staining. Pre-treatment of SH-SY5Y neuroblastoma cells with EGCG($1{\mu}M$) significantly attenuated $A{\beta}_{1-42}$-induced cytotoxicity. Potential cell signaling candidates involved in this neuroprotective effects were further examined. EGCG restored the reduced PKC, ERK, and JNK activities caused by $A{\beta}_{1-42}$ toxicity. In addition, gene expression analysis revealed that EGCG prevented both the $A{\beta}_{1-42}$-induced expression of a pro-apoptotic gene mRNA, Bad and Bax, and the decrease of an anti-apoptotic gene mRNA, Bcl-2 and Bcl-xl. These results suggest that the neuroprotective mechanism of EGCG against $A{\beta}_{1-42}$-induced apoptotic cell death includes stimulation of PKC, ERK, and JNK, and modulation of cell survival and death genes.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.9
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• pp.4587-4592
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• 2012

Purpose: This study used receiver operating characteristic curve to analyze Surveillance, Epidemiology and End Results (SEER) neuroblastoma (NB) and other peripheral nerve cell tumors (PNCT) outcome data. This study found under usage of radiotherapy in these patients. Materials and methods: This study analyzed socio-economic, staging and treatment factors available in the SEER database for NB and other PNCT. For the risk modeling, each factor was fitted by a generalized linear model to predict the outcome (soft tissue specific death, yes/no). The area under the receiver operating characteristic curve (ROC) was computed. Similar strata were combined to construct the most parsimonious models. A random sampling algorithm was used to estimate the modeling errors. Risk of neuroendocrine (other endocrine including thymus as coded in SEER) death was computed for the predictors. Results: There were 5261 patients diagnosed from 1973 to 2009 were included in this study. The mean follow up time (S.D.) was 83.8 (97.6) months. The mean (SD) age was 18 (25) years. About 30.45% of patients were un-staged. The SEER staging has high ROC (SD) area of 0.58 (0.01) among the factors tested. We simplified the 4-layered risk levels (local, regional, distant, un-staged/others) to a simpler 3-tiered model with comparable ROC area of 0.59 (0.01). Less than 50% of PNCT patients received radiotherapy (RT) including the ones with localized disease. This avoidance of RT use occurred in adults and children. Conclusion: The high under-staging rate may have precented patients from selecting definitive radiotherapy (RT) after surgery. Using RT for, especially, adult PNCT patients is a potential way to improve outcome.

• Journal of Preventive Medicine and Public Health
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• v.34 no.3
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• pp.183-190
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• 2001

Objective : To estimate the annual economic costs attributable to cigarette smoking in Korea. Methods : The costs were classified as being direct medical and non-medical costs, indirect costs and others. We focused on those costs related that are incurred in the treatment of selected diseases (cardiovascular diseases, respiratory diseases, and cancers), which have been proven to be caused by smoking. In addition to the basic costs of treatment, the additional amount of costs occurred due to smoking was obtained by computing the population attributable risk (PAR%) caused by smoking. To compute the PAR%, relative risks of smoking to the number of outpatient visits, hospitalizations, and the death were estimated using the Cox proportional hazard model, respectively. Our major data source was the 'Korea Medical Insurance Corporation (KMIC) cohort study,' which was composed of a total of 115,682 male and 67,932 female beneficiaries who had complete records of their smoking histories in the year of 1992. Results : The annual costs that could be attributable to smoking were estimated to be in the range of 2,847,500 million Won to 3,959,100 million Won. The maximum estimate of 3,959,100 million Won includes 233,100 million Won for medical costs, 5,100 million Won for transportation costs, 27,600 million Won for care giver's economic costs, 69,100 million Won in productivity loss, 3,435,000 million Won lost because of premature death, 172,100 million Won in costs resulting from passive smoke inhalation and 17,100 million Won for costs that resulted from fires that were caused by careless smoking. Conclusion : Our study confirms that the magnitude of the economic burden of smoking to Korean society is substantial. Therefore, this study provides strong evidence that there is a strong need for a national policy of tobacco control in Korea.

• Korean Journal of Biological Psychiatry
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• v.8 no.1
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• pp.3-19
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• 2001

Recent basic and clinical studies demonstrate a major role for neural plasticity in the etiology and treatment of depression and stress-related illness. The neural plasticity is reflected both in the birth of new cell in the adult brain(neurogenesis) and the death of genetically healthy cells(apoptosis) in the response to the individual's interaction with the environment. The neural plasticity includes adaptations of intracellular signal transduction pathway and gene expression, as well as alterations in neuronal morphology and cell survival. At the cellular level, repeated stress causes shortening and debranching of dendrite in the CA3 region of hippocampus and suppress neurogenesis of dentate gyrus granule neurons. At the molecular level, both form of structural remodeling appear to be mediated by glucocorticoid hormone working in concert with glutamate and N-methyl-D-aspartate(NMDA) receptor, along with transmitters such as serotonin and GABA-benzodiazepine system. In addition, the decreased expression and reduced level of brain-derived neurotrophic factor(BDNF) could contribute the atrophy and decreased function of stress-vulnerable hippocampal neurons. It is also suggested that atrophy and death of neurons in the hippocampus, as well as prefrontal cortex and possibly other regions, could contribute to the pathophysiology of depression. Antidepressant treatment could oppose these adverse cellular effects, which may be regarded as a loss of neural plasticity, by blocking or reversing the atrophy of hippocampal neurons and by increasing cell survival and function via up-regulation of cyclic adenosine monophosphate response element-binding proteins(CREB) and BDNF. In this article, the molecular and cellular mechanisms that underlie stress, depression, and action of antidepressant are precisely discussed.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.101-101
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• 2018

Resveratrol is a polyphenolic compound, which is a naturally occurring phytochemical and is found in a variety of plants, including food such as grapes, berries and peanuts. Although several studies have demonstrated that resveratrol possesses anti-cancer activity against various types of human cancer, the molecular mechanisms of resveratrol-mediated overcome drug resistance potential are unclear. In this study, we determined whether resveratrol attenuates drug resistance responses in 5-fluorouracil-resistant colon cancer (SNUC5/5-FUR) cells. Treatment with resveratrol significantly enhanced apoptosis in a concentration-dependent manner, which was associated with the modulation of anti- and/or pro-apoptotic protein expression, activation of caspases and activation of AMP-activated protein kinase. Resveratrol treatment also increased the induction of autophagy through up-regulation of autophagy-related genes such as Microtubule-associated protein 1A/1B-light chain 3, P62 and beclin-1. However, blocking of autophagy by bafilomycin A1 reduced apoptotic cell death, suggesting that resveratrol-induced autophagy functions as a cell death mechanism in SNUC5/5-FU cells. Although the further studies are needed, these findings suggest that resveratrol may have therapeutic potential to overcome drug resistance in colon cancer patients.

• Tuberculosis and Respiratory Diseases
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• v.72 no.4
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• pp.343-351
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• 2012

Background: The phosphoinositide 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling axis has emerged as a novel target for cancer therapy. Agents that inhibit this pathway are currently under development for lung cancer treatment. In the present study, we have tested whether dual inhibition of PI3K/Akt/mTOR signaling can lead to enahnced antitumor effects. We have also examined the role of autophagy during this process. Methods: We analyzed the combination effect of the mTOR inhibitor, temsirolimus, and the Akt inhibitor, GSK690693, on the survival of NCI-H460 and A549 non-small cell lung cancer cells. Cell proliferation was determined by MTT assay and apoptosis induction was evaluated by flow cytometry and terminal deoxynucleotidyl transferase dUTP nick end labeling assay. Autophagy induction was also evaluated by acridine orange staining. Changes of apoptosis or autophagy-related proteins were evaluated by western blot analysis. Results: Combination treatment with temsirolimus and GSK690693 caused synergistically increased cell death in NCI-H460 and A549 cells. This was attributable to increased induction of apoptosis. Caspase 3 activation and poly(ADP-ribose) polymerase cleavage accompanied these findings. Autophagy also increased and inhibition of autophagy resulted in increased cell death, suggesting its cytoprotective role during this process. Conclusion: Taken together, our results suggest that the combination of temsirolimus and GSK690693 could be a novel strategy for lung cancer therapy. Inhibition of autophagy could also be a promising method of enhancing the combination effect of these drugs.

• BMB Reports
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• v.53 no.6
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• pp.311-316
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• 2020

Cholestasis is a condition in which the bile duct becomes narrowed or clogged by a variety of factors and bile acid is not released smoothly. Bile acid-induced liver injury is facilitated by necrotic cell death, neutrophil infiltration, and inflammation. Metformin, the first-line treatment for type 2 diabetes, is known to reduce not only blood glucose but also inflammatory responses. In this study, we investigated the effects of metformin on liver injury caused by cholestasis with bile acid-induced hepatocyte injury. Static bile acid-induced liver injury is thought to be related to endoplasmic reticulum (ER) stress, inflammatory response, and chemokine expression. Metformin treatment reduced liver injury caused by bile acid, and it suppressed ER stress, inflammation, chemokine expression, and neutrophil infiltration. Similar results were obtained in mouse primary hepatocytes exposed to bile acid. Hepatocytes treated with tauroursodeoxycholic acid, an ER stress inhibitor, showed inhibition of ER stress, as well as reduced levels of inflammation and cell death. These results suggest that metformin may protect against liver injury by suppressing ER stress and inflammation and reducing chemokine expression.

• The Korean Journal of Physiology and Pharmacology
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• v.25 no.4
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• pp.273-280
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• 2021

Lung cancer despite advancement in the medical field continues to be a major threat to human lives and accounts for a high proportion of fatalities caused by cancers globally. The current study investigated vanillin oxime, a derivative of vanillin, against lung cancer cells for development of treatment and explored the mechanism. Cell viability changes by vanillin oxime were measured using MTT assay. Vanillin oxime-mediated apoptosis was detected in A549 and NCI-H2170 cells at 48 h of exposure by flow cytometry. The CEBP homologous protein (CHOP) and death receptor 5 (DR5) levels were analysed by RT-PCR and protein levels by Western blotting. Vanillin oxime in concentration-dependent way suppressed A549 and NCI-H2170 cell viabilities. On exposure to 12.5 and 15 μM concentrations of vanillin oxime elevated Bax, caspase-3, and -9 levels in A549 and NCI-H2170 cells were observed. Vanillin oxime exposure suppressed levels of Bcl-2, survivin, Bcl-xL, cFLIP, and IAPs proteins in A549 and NCI-H2170 cells. It stimulated significant elevation in DR4 and DR5 levels in A549 and NCI-H2170 cells. In A549 and NCI-H2170 cells vanillin oxime exposure caused significant (p < 0.05) enhancement in CHOP and DR5 mRNA expression. Vanillin oxime exposure of A549 and NCI-H2170 cells led to significant (p < 0.05) enhancement in levels of phosphorylated extracellular-signal-regulated kinase and c-Jun N-terminal kinase. Thus, vanillin oxime inhibits pulmonary cell proliferation via induction of apoptosis through tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) mediated pathway. Therefore, vanillin oxime may be studied further to develop a treatment for lung cancer.

• Biomolecules & Therapeutics
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• v.32 no.1
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• pp.77-83
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• 2024

Alzheimer's disease (AD) is a neurodegenerative disease characterized by neuronal cell death and memory impairment. Corticosterone (CORT) is a glucocorticoid hormone produced by the hypothalamic-pituitary-adrenal axis in response to a stressful condition. Excessive stress and high CORT levels are known to cause neurotoxicity and aggravate various diseases, whereas mild stress and low CORT levels exert beneficial actions under pathophysiological conditions. However, the effects of mild stress on AD have not been clearly elucidated yet. In this study, the effects of low (3 and 30 nM) CORT concentration on Aβ_25-35-induced neurotoxicity in SH-SY5Y cells and underlying molecular mechanisms have been investigated. Cytotoxicity caused by Aβ_25-35 was significantly inhibited by the low concentration of CORT treatment in the cells. Furthermore, CORT pretreatment significantly reduced Aβ_25-35-mediated pro-apoptotic signals, such as increased Bim/Bcl-2 ratio and caspase-3 cleavage. Moreover, low concentration of CORT treatment inhibited the Aβ_25-35-induced cyclooxygenase-2 and pro-inflammatory cytokine expressions, including tumor necrosis factor-α and interleukin-1β. Aβ_25-35 resulted in intracellular accumulation of reactive oxygen species and lipid peroxidation, which were effectively reduced by the low CORT concentration. As a molecular mechanism, low CORT concentration activated the nuclear factor-erythroid 2-related factor 2, a redox-sensitive transcription factor mediating cellular defense and upregulating the expression of antioxidant enzymes, such as NAD(P)H:quinone oxidoreductase, glutamylcysteine synthetase, and manganese superoxide dismutase. These findings suggest that low CORT concentration exerts protective actions against Aβ_25-35-induced neurotoxicity and might be used to treat and/or prevent AD.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.1
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• pp.475-481
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• 2014

Background: Pereskia sacharosa is a genus of cacti widely used in folk medicine for cancer-related treatment. Anti-proliferative effects have been studied in recent years against colon, breast, cervical and lung cancer cell lines, with promising results. We here extended study of anti-proliferative effects to a blood malignancy, leukemia. Materials and Methods: Two leukemic cell lines, MV4-11 (acute myeloid leukemia) and K562 (chronic myeloid leukemia), were studied. $IC_{50}$ concentrations were determined and apoptosis and cell cycle regulation were studied by flow cytometric analysis. The expression of apoptosis and cell-cycle related regulatory proteins was assessed by Western blotting. Results: P sacharosa inhibited growth of MV4-11 and K562 cells in a dose-dependent manner. The mode of cell death was via induction of intrinsic apoptotic pathways and cell cycle arrest. There was profound up-regulation of cytochrome c, caspases, p21 and p53 expression and repression of Akt and Bcl-2 expression in treated cells. Conclusions: These results suggest that P sacharosa induces leukemic cell death via apoptosis induction and changes in cell cycle checkpoint, thus deserves further study for anti-leukemic potential.