• Korean Journal of Clinical Laboratory Science
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• v.52 no.1
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• pp.62-68
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• 2020

Cisplatin (CDDP) is a chemotherapy agent used for patients with ovarian cancers. CDDP activates multiple signaling pathways, which causes various cellular reactions according to the type of cancer cells. Therefore, it is difficult to clearly conclude its signaling pathways. The purpose of this study is to determine the role of the signal protein of Akt/ERK1/2 and MAPK by CDDP-induced apoptosis in ovarian cancer cells (SKOV3). As a result, the number of apoptosis increased according to the TUNEL assay, and flow cytometric analysis confirmed that the percentage of sub-G1 early apoptosis was 8.73% higher than the control. The PARP and caspase-3 activity that appeared in the process of apoptosis was increased and the Bcl-2 expression was decreased. It was verified that the Akt and ERK1/2 activity was decreased, and p38 and JNK activity increased in a time dependent fashion. In conclusion, these results demonstrate that cisplatin inhibits the proliferation of ovarian cancer cells by inhibiting Akt activity and induces apoptosis by modulating the MAPK signaling pathway. However, a decrease in the ERK1/2 activity by CDDP was the opposite result to the result shown from the HeLa cells. For this reason, further research on signaling pathways is necessary. These results are expected to be useful for ovarian cancer treatment strategies targeting the MAPK pathway.

• Physical Therapy Rehabilitation Science
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• v.3 no.1
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• pp.33-37
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• 2014

Objective: Low intensity pulsed ultrasound (LIPUS) has been shown to accelerate cell proliferation and tissue healing in both animal models and clinical trials. However, details of the clinical effects of LIPUS have not been well characterized. The aim of this study was to investigate the effect of LIPUS on mitogen-activated protein kinase (MAPK) activation in rat articular chondrocytes. Design: Cross-sectional study. Methods: Chondrocyte were cultured in six well cell culture plates for 72 hours at $37^{\circ}C$ with 5% $CO_2$, and then exposed to LIPUS at 1.5 MHz frequency and $30-mW/cm^2$ power. Changes in chondrocyte activities were evaluated in response to oxydative stress in dose-dependent (0 and 300 uM) and time-dependent (0-24 hr) manner. The cell viability were analyzed using MTT [3-(4.5-dimethylthiazol-2-yl)-2.5 diphenyltetrazolium bromide]. The expression of p38 MAPK was measured using western blotting. Results: Oxidative stress was induced in rat chondrocytes using hydrogen peroxide ($H_2O_2$). The cell viability was decreased in chondrocytes after the $H_2O_2$ dose and time-dependent treatment. The p38 MAPK phosphorylation occurred at a significantly increased rate after $H_2O_2$ treated (p<0.05). Expression of p38 MAPK was decreased in the p38 inhibitor groups compared with the oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways (p<0.05). Conclusions: It could be concluded that LIPUS can inhibit oxidative stress-induced chondrocyte damage via the p38 MAPK signaling pathways.

• Toxicological Research
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• v.35 no.1
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• pp.93-101
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• 2019

Tetrabromobisphenol A (TBBPA), the most common industrial brominated flame retardant, acts as a cytotoxic, neurotoxic, and immunotoxicant, causing inflammation and tumors. However, the mechanism of TBBPA-induced matrix metalloproteinase-9 (MMP-9) expression in human breast cancer cells is not clear. In human breast cancer MCF-7 cells, treatment with TBBPA significantly induced the expression and promoter activity of MMP-9. Transient transfection with MMP-9 mutation promoter constructs verified that $NF-{\kappa}B$ and AP-1 response elements are responsible for the effects of TBBPA. Furthermore, TBBPA-induced MMP-9 expression was mediated by $NF-{\kappa}B$ and AP-1 transcription activation as a result of the phosphorylation of the Akt and MAPK signaling pathways. Moreover, TBBPA-induced activation of Akt/MAPK pathways and MMP-9 expression were attenuated by a specific NADPH oxidase inhibitor, and the ROS scavenger. These results suggest that TBBPA can induce cancer cell metastasis by releasing MMP-9 via ROS-dependent MAPK, and Akt pathways in MCF-7 cells.

• Korean Journal of Poultry Science
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• v.44 no.3
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• pp.199-209
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• 2017

Mitogen-activated protein kinase (MAPK) signaling pathways play a key role in innate immunity, inflammation, cell proliferation, cell differentiation, and cell death. The main objective of this study was to investigate the expression level of candidate MAPK pathway genes in the intestinal mucosal layer of two genetically disparate chicken lines (Marek's disease-resistant line 6.3 and Marek's disease-susceptible line 7.2) induced with necrotic enteritis (NE). Using high-throughput RNA sequencing, we investigated 178 MAPK signaling pathway related genes that were significantly and differentially expressed between the intestinal mucosal layers of the NE-afflicted and control chickens. In total, 15 MAPK pathway genes were further measured by quantitative real-time PCR(qRT-PCR) and the results were consistent with the RNA-sequencing data. All 178 identified genes were annotated through Gene Ontology and mapped onto the KEGG chicken MAPK signaling pathway. Several key genes of the MAPK pathway, ERK1/2, JNK1-3, p38 MAPK, MAP2K1-4, $NF-{\kappa}B1/2$, c-Fos, AP-1, Jun-D, and Jun, were differentially expressed in the two chicken lines. Therefore, we believe that RNA sequencing and qRT-PCR analysis provide resourceful information for future studies on MAPK signaling of genetically disparate chicken lines in response to pathogens.

• Mycobiology
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• v.37 no.3
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• pp.161-170
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• 2009

Cryptococcus neoformans is a basidiomycete human fungal pathogen that causes meningoencephalitis in both immunocompromised and immunocompetent individuals. The ability to sense and respond to diverse extracellular signals is essential for the pathogen to infect and cause disease in the host. Four major stress-activated signaling (SAS) pathways have been characterized in C. neoformans, including the HOG (high osmolarity glycerol response), PKC/Mpk1 MAPK (mitogen-activated protein kinase), calcium-dependent calcineurin, and RAS signaling pathways. The HOG pathway in C. neoformans not only controls responses to diverse environmental stresses, including osmotic shock, UV irradiation, oxidative stress, heavy metal stress, antifungal drugs, toxic metabolites, and high temperature, but also regulates ergosterol biosynthesis. The PKC(protein kinase C)/Mpk1 pathway in C. neoformans is involved in a variety of stress responses, including osmotic, oxidative, and nitrosative stresses and breaches of cell wall integrity. The $Ca^{2+}$/calmodulin- and Ras-signaling pathways also play critical roles in adaptation to certain environmental stresses, such as high temperature and sexual differentiation. Perturbation of the SAS pathways not only impairs the ability of C. neoformans to resist a variety of environmental stresses during host infection, but also affects production of virulence factors, such as capsule and melanin. A drug(s) capable of targeting signaling components of the SAS pathway will be effective for treatment of cryptococcosis.

• Nutrition Research and Practice
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• v.9 no.4
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• pp.343-349
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• 2015

BACKGROUND/OBJECTIVES: Fermentation of dietary fiber results in production of various short chain fatty acids in the colon. In particular, butyrate is reported to regulate the physical and functional integrity of the normal colonic mucosa by altering mucin gene expression or the number of goblet cells. The objective of this study was to investigate whether butyrate modulates mucin secretion in LS174T human colorectal cells, thereby influencing the adhesion of probiotics such as Lactobacillus and Bifidobacterium strains and subsequently inhibiting pathogenic bacteria such as E. coli. In addition, possible signaling pathways involved in mucin gene regulation induced by butyrate treatment were also investigated. MATERIALS/METHODS: Mucin protein content assay and periodic acid-Schiff (PAS) staining were performed in LS174T cells treated with butyrate at various concentrations. Effects of butyrate on the ability of probiotics to adhere to LS174T cells and their competition with E. coli strains were examined. Real time polymerase chain reaction for mucin gene expression and Taqman array 96-well fast plate-based pathway analysis were performed on butyrate-treated LS174T cells. RESULTS: Treatment with butyrate resulted in a dose-dependent increase in mucin protein contents in LS174T cells with peak effects at 6 or 9 mM, which was further confirmed by PAS staining. Increase in mucin protein contents resulted in elevated adherence of probiotics, which subsequently reduced the adherent ability of E. coli. Treatment with butyrate also increased transcriptional levels of MUC3, MUC4, and MUC12, which was accompanied by higher gene expressions of signaling kinases and transcription factors involved in mitogen-activated protein kinase (MAPK) signaling pathways. CONCLUSIONS: Based on our results, butyrate is an effective regulator of modulation of mucin protein production at the transcriptional and translational levels, resulting in changes in the adherence of gut microflora. Butyrate potentially stimulates the MAPK signaling pathway in intestinal cells, which is positively correlated with gut defense.

• Archives of Pharmacal Research
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• v.23 no.1
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• pp.1-16
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• 2000

Many natural products elicit diverse pharmacological effects. Using two classes of potential chemopreventive compounds, the phenolic compounds and the isothiocyanates, we review the potential utility of two signaling events, the mitogen-activated protein kinases (MAPKs) and the ICE/Ced-3 proteases (caspases) stimulated by these agents in mammalian cell lines. Studies with phenolic antioxidants (BHA, tBHQ), and natural products (flavonoids; EGCG, ECG, and isothiocyanates; PEITC, sulforaphane), provided important insights into the signaling pathways induced by these compounds. At low concentrations, these chemicals may activate the MAPK (ERK2, JNK1, p38) leading to gene expression of survival genes (c-Fos, c-Jun) and defensive genes (Phase II detoxifying enzymes; GST, QR) resulting in survival and protective mechanisms (homeostasis response). Increasing the concentrations of these compounds will additionally activate the caspase pathway, leading to apoptosis (potential cytotoxicity). Further increment to suprapharmacological concentrations will lead to nonspecific necrotic cell death. The wider and narrow concentration ranges between the activation of MAPK/gene induction and caspases/cell death exhibited by phenolic compounds and isothiocyanates, respectively, in mammalian cells, may reflect their respective therapeutic windows in vivo. Consequently, the studies of signaling pathways elicited by natural products will advance our understanding of their efficacy and safety, of which many man become important therapeuitc drugs of the future.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.11
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• pp.4519-4525
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• 2014

Oleanolic acid (OA) is a nutritional component widely distributed in various vegetables. Although it has been well recognized for decades that OA exerts certain anti-tumor activity by inducing mitochondria-dependent apoptosis, it is still unclear that what molecular signaling is responsible for this effect. In this study, we employed cancer cell lines, A549, BXPC-3, PANC-1 and U2OS to elucidate the molecular mechanisms underlying OA anti-tumor activity. We found that activation of MAPK pathways, including p-38 MAPK, JNK and ERK, was triggered by OA in both a dose and time-dependent fashion in all the tested cancer cells. Activation was accompanied by cleavage of caspases and PARP as well as cytochrome C release. SB203580 (p38 MAPK inhibitor), but not SP600125 (JNK inhibitor) and U0126 (ERK inhibitor), rescued the pro-apoptotic effect of OA on A549 and BXPC-3 cells. OA induced p38 MAPK activation promoted mitochondrial translocation of Bax and Bim, and inhibited Bcl-2 function by enhancing their phosphorylation. OA can induce reactive oxygen species (ROS)-dependent ASK1 activation, and this event was indispensable for p38 MAPK-dependent apoptosis in cancer cells. In vivo, p38 MAPK knockdown A549 tumors proved resistant to the growth-inhibitory effect of OA. Collectively, we elucidated that activation of ROS/ASK1/p38 MAPK pathways is responsible for the apoptosis stimulated by OA in cancer cells. Our finding can contribute to a better understanding of molecular mechanisms underlying the antitumor activity of nutritional components.

• Korean Journal of Pharmacognosy
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• v.48 no.2
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• pp.155-159
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• 2017

Cudrania tricuspidata Bureau (Moraceae) is a traditional oriental medicine that has been widely used as anti-oxidant, anti-inflammatory and immunomodulatory in Korea. This study was performed that the 70% ethanol extract of the roots of C. tricuspidata (CTE) suppressed receptor activator of NF-${\kappa}B$ ligand (RANKL)-induced osteoclastogenesis, actin ring formation in RAW 264.7 cell lines. CTE significantly inhibited the JNK/mitogen-activated protein kinase (MAPK) signaling pathway without affecting ERK and p38 signaling in RANKL-stimulated RAW 264.7 cells. Also, CTE inhibited RANKL-induced expression of c-Fos, an upstream activator of NFATc1. Consequently, CTE suppresses osteoclast differentiation by inhibiting RANKL induced MAPK signaling pathways and disrupts the actin rings in mature osteoclasts. Thus, CTE can be used for the development of osteoporosis treatment drug with a natural material.

• Molecules and Cells
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• v.40 no.1
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• pp.17-23
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• 2017

Mitogen-activated protein kinase (MAPK) signaling cascades play critical roles in various cellular events in plants, including stress responses, innate immunity, hormone signaling, and cell specificity. MAPK-mediated stress signaling is also known to negatively regulate nitrogen-fixing symbiotic interactions, but the molecular mechanism of the MAPK signaling cascades underlying the symbiotic nodule development remains largely unknown. We show that the MtMKK5-MtMPK3/6 signaling module negatively regulates the early symbiotic nodule formation, probably upstream of ERN1 (ERF Required for Nodulation 1) and NSP1 (Nod factor Signaling Pathway 1) in Medicago truncatula. The overexpression of MtMKK5 stimulated stress and defense signaling pathways but also reduced nodule formation in M. truncatula roots. Conversely, a MAPK specific inhibitor, U0126, enhanced nodule formation and the expression of an early nodulation marker gene, MtNIN. We found that MtMKK5 directly activates MtMPK3/6 by phosphorylating the TEY motif within the activation loop and that the MtMPK3/6 proteins physically interact with the early nodulation-related transcription factors ERN1 and NSP1. These data suggest that the stress signaling-mediated MtMKK5/MtMPK3/6 module suppresses symbiotic nodule development via the action of early nodulation transcription factors.