• Journal of Microbiology and Biotechnology
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• v.24 no.5
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• pp.696-703
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• 2014

Clostridium difficile causes mucosal damage and diarrhea by releasing two exotoxins: toxin A and toxin B. C. difficile colitis is associated with alterations in bowel flora and the failure to mount an effective antibody response. The aim of the current study was to investigate whether antitoxin sera prevent toxin-A-induced apoptosis, cytoskeletal disaggregation, cell detachment, and tight junction loss in cultured colonic epithelial cells. Serum samples were isolated from mice that survived a C. difficile infection following antibiotic treatment, and the antitoxin effects of these samples were investigated in toxin-A-exposed HT29 colonic epithelial cells and a toxin-A-induced animal model of gut inflammation. Unchallenged mice did not produce IgG against toxin A, whereas serum (antiserum) from C. difficile-challenged mice showed significant IgG responses against toxin A. Treatment with the antiserum markedly inhibited mucosal damage and inflammation in the toxin-A-treated mouse model. In contrast to control mouse serum, the antiserum also markedly inhibited toxin-A-induced DNA fragmentation, dephosphorylation of paxillin and Epo receptor (EpoR), deacetylation of tubulin, and upregulation of p21(WAF1/CIP1) and p53. Taken together, these results reveal that the generated antitoxin serum has biotherapeutic effects in preventing various C. difficile toxin-A-induced cellular toxicities.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.3
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• pp.1391-1396
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• 2014

Non-small cell lung cancer (NSCLC) is the most common type of lung cancer and the most common cause of lung cancer death. Currently, the epidermal growth factor receptor inhibitor gefitinib is used for its treatment; however, drug resistance is a major obstacle. Expression of Met has been associated with both primary and acquired resistance to gefitinib, but the mechanisms regulating its expression are not fully understood. Recently, miRNAs such as miR-130a have been shown to play a role in gefitinib resistance, but importance in NSCLC and relationships with Met have not been fully explored. Here we show that miR-130a is over-expressed in gefitinibsensitive NSCLC cell lines, but is low in gefitinib-resistant NSCLC cell lines. Moreover, miR-130a expression was negatively correlated with that of Met. Further analysis revealed that over-expression of miR-130a increased cell apoptosis and inhibited proliferation of NSCLC cells treated with gefitinib, whereas lowering the expression of miR-130a decreased cell apoptosis and promoted cell proliferation after treatment with gefitinib in both gefitinib-sensitive and -resistant NSCLC cell lines, suggesting that miR-130a overcomes gefitinib resistance. We also demonstrated that miR-130a binds to the 3'-UTR of Met and significantly suppresses its expression. Finally, our results showed that over-expressing Met could "rescue" the functions of miR-130a regarding cell apoptosis and proliferation after cells are treated with gefitinib. These findings indicate that the miR-130a/Met axis plays an important role in gefitinib resistance in NSCLC. Thus, the miR-130a/Met axis may be an effective therapeutic target in gefitinib-resistant lung cancer patients.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.12
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• pp.5023-5028
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• 2014

Sendai virus strain Tianjin is a novel genotype. Here, we investigate the antitumor and proapoptotic effects of ultraviolet-inactivated Sendai virus strain Tianjin (UV-Tianjin) on human breast cancer MDA-MB-231 cells in vitro, as well as the involvement of the apoptotic pathway in the mechanism of UV-Tianjin-induced antitumor effects. MTT assays showed that treatment with UV-Tianjin dose-dependently inhibited the proliferation of MDA-MB-231 cells but not normal MCF 10A breast epithelium cells. Hoechst staining and flow cytometric analysis revealed that UV-Tianjin induced apoptosis of MDA-MB-231 cells in a dose-dependent manner. Moreover, UV-Tianjin treatment resulted in reduction in the mitochondria membrane potential (MMP) and release of cytochrome complex (cyt c) via regulation of Bax and Bcl-2, as well as activation of caspase-9, caspase-3, Fas, FasL and caspase-8 in MDA-MB-231 cells. In summary, our study suggests that UV-Tianjin exhibits anticancer activity in human breast cancer MDA-MB-231 cells through inducing apoptosis, which may involve both the endogenous mitochondrial and exogenous death receptor pathways.

• Journal of Microbiology and Biotechnology
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• v.25 no.3
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• pp.343-352
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• 2015

H9 is an ethanol extract prepared from nine traditional/medicinal herbs. This study was focused on the anticancer effect of H9 in non-small-cell lung cancer cells. The effects of H9 on cell viability, apoptosis, mitochondrial membrane potential (MMP; ${\Delta}\psi_{m}$), and apoptosisrelated protein expression were investigated in A549 human lung cancer cells. In this study, H9-induced apoptosis was confirmed by propidium iodide staining, expression levels of mRNA were determined by reverse transcriptase polymerase chain reaction, protein expression levels were checked by western blot analysis, and MMP (${\Delta}\psi_{m}$) was measured by JC-1 staining. Our results indicated that H9 decreased the viability of A549 cells and induced cell morphological changes in a dose-dependent manner. H9 also altered expression levels of molecules involved in the intrinsic signaling pathway. H9 inhibited Bcl-xL expression, whereas Bax expression was enhanced and cytochrome C was released. Furthermore, H9 treatment led to the activation of caspase-3/caspase-9 and proteolytic cleavage of poly(ADP-ribose) polymerase; the MMP was collapsed by H9. However, the expression levels of extrinsic pathway molecules such as Fas/FasL, TRAIL/TRAIL-R, DR5, and Fas-associated death receptor were downregulated by H9. These results indicated that H9 inhibited proliferation and induced apoptosis by activating intrinsic pathways but not extrinsic pathways in human lung cancer cells. Our results suggest that H9 can be used as an alternative remedy for human non-small-cell lung cancer.

• The Korean Journal of Physiology and Pharmacology
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• v.18 no.1
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• pp.61-66
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• 2014

Lung cancer is still the number one cause of death from cancer worldwide. The clinical effect of platinum-based chemotherapy for non-small cell lung cancer is constrained by the resistance to drug. To overcome chemo-resistance, various modified treatment including combination therapy has been used, but overall survival has not been improved yet. In this study, chemo-resistant lung cancer cells, A549/Cis and H460/Cis, were developed by long-term exposure of cells to cisplatin and the proliferative capability of these resistant cells was verified to be reduced. We found cytotoxic effect of epigallocatechin gallate (EGCG), a major catechin derived from green tea, on both the parental lung cancer cells, A549 and H460, and their cisplatin resistant cells, A549/Cis and H460/Cis. ELISA and Western blot analysis revealed that EGCG was able to increase interlukine-6 (IL-6) production per cell, whereas its downstream effector Signal transducers and activators of transcription 3 (STAT3) phosphorylation was not changed by EGCG, indicating that IL-6/STAT3 axis is not the critical signaling to be inhibited by EGCG. We next found that EGCG suppresses the expression of both Axl and Tyro 3 receptor tyrosine kinases at mRNA and protein level, explaining the cytotoxic effect of EGCG on lung cancer cells, especially, regardless of cisplatin resistance. Taken together, these data suggest that EGCG impedes proliferation of lung cancer cells including their chemo-resistant variants through downregulation of Axl and Tyro 3 expression.

• The Korean Journal of Physiology and Pharmacology
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• v.21 no.1
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• pp.125-131
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• 2017

Status epilepticus is the most common serious neurological condition triggered by abnormal electrical activity, leading to severe and widespread cell loss in the brain. Lithium has been one of the main drugs used for the treatment of bipolar disorder for decades, and its anticonvulsant and neuroprotective properties have been described in several neurological disease models. However, the therapeutic mechanisms underlying lithium's actions remain poorly understood. The muscarinic receptor agonist pilocarpine is used to induce status epilepticus, which is followed by hippocampal damage. The present study was designed to investigate the effects of lithium post-treatment on seizure susceptibility and hippocampal neuropathological changes following pilocarpine-induced status epilepticus. Status epilepticus was induced by administration of pilocarpine hydrochloride (320 mg/kg, i.p.) in C57BL/6 mice at 8 weeks of age. Lithium (80 mg/kg, i.p.) was administered 15 minutes after the pilocarpine injection. After the lithium injection, status epilepticus onset time and mortality were recorded. Lithium significantly delayed the onset time of status epilepticus and reduced mortality compared to the vehicle-treated group. Moreover, lithium effectively blocked pilocarpine-induced neuronal death in the hippocampus as estimated by cresyl violet and Fluoro-Jade B staining. However, lithium did not reduce glial activation following pilocarpine-induced status epilepticus. These results suggest that lithium has a neuroprotective effect and would be useful in the treatment of neurological disorders, in particular status epilepticus.

• Journal of Life Science
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• v.22 no.5
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• pp.697-701
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• 2012

Activated protein C (APC) has an anticoagulant effect and a non-hemostatic effect such as regulation of cell metastasis and modulation of inflammation. In this study, we investigated whether APC could modulate apoptosis in cancer cells. Tumor necrosis factor (TNF)-${\alpha}$, cyclohexamide, and FAS markedly induced apoptosis in human renal carcinoma Caki cells. When Caki cells were pretreated with APC, the percentage of death receptor-induced apoptosis did not change. Furthermore, we checked the effect of APC on tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in human glioma T98G and human breast carcinoma MDA231 cells. APC also had no effect on TRAIL-induced apoptosis in both cell lines. However, pretreatment with APC inhibited combination treatment (kahweol plus TRAIL and kahweol plus melatonin)-induced apoptosis and PARP cleavage in Caki cells. Taken together, our results suggest that APC can modulate anti-cancer therapeutic efficiency.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.15
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• pp.6215-6223
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• 2015

Tyrosine phosphorylation plays an important role in regulating human physiological and pathological processes. Functional stabilization of tyrosine phosphorylation largely contributes to the balanced, coordinated regulation of protein tyrosine kinases (PTKs) and protein tyrosine phosphatases (PTPs). Research has revealed PTPs play an important suppressive role in carcinogenesis and progression by reversing oncoprotein functions. Receptor-type protein tyrosine phosphatase O (PTPRO) as one member of the PTPs family has also been identified to have some roles in tumor development. Some reports have shown PTPRO over-expression in tumors can not only inhibit the frequency of tumor cell division and induce tumor cell death, but also suppress migration. However, the tumor-suppression mechanisms are very complex and understanding is incomplete, which in some degree blocks the further development of PTPRO. Hence, in order to resolve this problem, we here have summarized research findings to draw meaningful conclusions. We found tumor-suppression mechanisms of PTPRO to be diverse, such as controlling G0/G1 of the tumor cell proliferation cycle, inhibiting substrate phosphorylation, down-regulating transcription activators and other activities. In clinical anticancer efforts, expression level of PTPRO in tumors can not only serve as a biomarker to monitor the prognosis of patients, but act as an epigenetic biomarker for noninvasive diagnosis. In addition, the re-activation of PTPRO in tumor tissues, not only can induce tumor volume reduction, but also enhance the susceptibility to chemotherapy drugs. So, we can propose that these research findings of PTPRO will not only support new study ideas and directions for other tumor-suppressors, importantly, but also supply a theoretical basis for researching new molecular targeting agents in the future.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5463-5468
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• 2014

MicroRNAs might act as oncogenes or tumor suppressors in cancer. Recent studies have shown that miR-421 is up-regulated in human gastric cancer. Here, we found that miR-421 was over-expressed in gastric cancer tissues and cell lines. Bioinformatics analysis predicted that the caspase-3 gene was a target of miR-421. Caspase-3 was negatively regulated by miR-421 at the post-transcriptional level. Bax and Bcl-2 were also regulated by miR-421. Moreover, tumor necrosis factor receptor-I and -II, death receptors in the apoptosis pathway, were up-regulated by miR-421. The over-expression of miR-421 promoted gastric cancer cell growth and inhibited apoptosis of the BGC-823 gastric cancer cell line. These observations indicate that miR-421 acts as a tumor promoter by targeting the caspase-3 gene and preventing apoptosis of gastric cancer cells through inhibition of caspase-3 expression. These findings contribute to our understanding of the functions of miR-421 in gastric cancer.

• BMB Reports
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• v.35 no.3
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• pp.267-272
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• 2002

TNF-$\alpha$ elicits various responses including apoptosis, proliferation, and differentiation according to cell type. In neuronal PC12 cells, TNF-$\alpha$ induces moderate apoptosis while lipopolysarccaharide or trophic factor deprivation can potentiate apoptosis that is induced by TNF-$\alpha$. TNF-$\alpha$ initiates various signal transduction pathways leading to the activation of the caspase family, NF-${\kappa}B$, Jun N-terminal kinase, and p38 MAPK via the death domain that contains the TNF-$\alpha$ receptor. Inhibition of translation using cycloheximide greatly enhanced the apoptotic effect of TNF-$\alpha$. This implies that the induction of anti-apoptotic genes for survival by TNF-$\alpha$ may be able to protect PC12 cells from apoptosis. Accordingly, Bcl-2, an anti-apoptotic genes for survival by TNF-$\alpha$ may be able to protect PC12 cells from apoptosis. Accordingly, Bcl-2, an anti-apoptotic Bcl-2 family member, was highly expressed in response to TNF-$\alpha$. In this study, we examined the anti-apoptotic role of p38 MAPK that is activated by TNF-$\alpha$ in neuronal PC12 cells. The phosphorylation of p38 MAPK in response to TNF-$\alpha$ slowly increased and lasted several hours in the PC12 cell and DRG neuron. This specific inhibitor of p38 MAPK, SB202190, significantly enhanced the apoptosis that was induced by TNF-$\alpha$ in PC12 cells. This indicates that the activation of p38 MAPK could protect PC12 cells from apoptosis since there is no known role of p38 MAPK in resoonse to TNF-$\alpha$ in neuron. This discovery could be evidence for the neuroprotective role of the p38 MAPK.