• International Journal of Oncology
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• v.56 no.6
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• pp.1509-1520
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• 2020

The phosphoinositide 3-kinase (PI3K) signaling pathway plays an important role in human cancer as it regulates critical cellular functions, such as survival, proliferation and metabolism. In the present study, a novel PI3Kα inhibitor (HS-146) was synthesized and its anticancer effects on MCF-7, MDA-MB-231, SKBR3 and BT-474 human breast cancer cell lines were confirmed. HS-146 was found to be most effective in inhibiting the proliferation of MCF-7 cells and in inducing cell cycle arrest in the G0/G1 phase by downregulating cyclin D1, cyclin E, cyclin-dependent kinase (Cdk)2 and Cdk4, and upregulating p21Waf1/Cip1 protein levels in this cell line. The induction of apoptosis by HS-146 was confirmed by DAPI staining and western blot analysis. Cell shrinkage and nuclear condensation, which are typical morphological markers of apoptosis, were increased by HS-146 in the MCF-7 cells in a concentration-dependent manner, and HS-146 also increased the protein expression levels of cleaved poly(ADP-ribose) polymerase (PARP) and decreased the protein expression levels of Mcl-1 and caspase-7. In addition, HS-146 effectively decreased the phosphorylation levels of downstream PI3K effectors, such as Akt, mammalian target of rapamycin (mTOR), glycogen synthase kinase 3β (GSK3β), p70S6K1 and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1). Hypoxia-inducible factor (HIF)-1α and vascular endothelial growth factor (VEGF) expression were also suppressed by HS-146 under hypoxic conditions, and HS-146 inhibited the migration and invasion of MCF-7 cells in a concentration-dependent manner. On the whole, the findings of the present study suggest that HS-146, a novel PI3Kα inhibitor, may be an effective novel therapeutic candidate that suppresses breast cancer proliferation and metastasis by inhibiting the PI3K/Akt/mTOR pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.9
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• pp.5017-5021
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• 2013

Objective: MicroRNAs (miRNAs) are a small class of non-coding, single-stranded RNAs with a critical role in genesis and maintenance of renal cancer mainly through binding to 3'-untranslated regions (3'UTR) of target mRNAs, which causes a block of translation and/or mRNA degradation. The aim of the present study was to investigate the potential effects of miR-122 in human renal cell carcinomas. Methods: The expression level of miR-122 was quantified by qRT-PCR. MTT, colony formation, invasion and migration assays were used to explore the potential functions of miR-122 in human renal cell carcinoma cells. Results: Cellular growth, invasion and migration in two A498 and 786-O cells were significantly increased after miR-122 transfection. Further experiments demonstrated that overexpression of miR-122 resulted in the increase of phospho-Akt (Ser473) and phospho-mTOR (Ser2448), then activation of mTOR targets, p70S6K and 4E-BP1. Conclusions: The up-regulation of miR-122 may play an important role in the progress of renal cancer through activating PI3K/Akt signal pathway and could be a potential molecular target for anti-cancer therapeutics.

• Journal of Life Science
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• v.29 no.11
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• pp.1251-1257
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• 2019

Peptidoglycan (PG) is found in atheromatous lesions of arteries, where monocytes/macrophages express inflammatory cytokines, including tumor necrosis factor-alpha ($TNF-{\alpha}$). This study investigated the effects of PG on $TNF-{\alpha}$ expression and examined possible cellular factors involved in $TNF-{\alpha}$ upregulation. The overall aim was to identify the molecular mechanisms underlying inflammatory responses to bacterial pathogen-associated molecular patterns in the artery. Exposure of human THP-1 monocytic cells to PG enhanced the secretion of $TNF-{\alpha}$ and induced its gene transcription. Inhibition of TLR-2/4 with OxPAPC significantly inhibited $TNF-{\alpha}$ gene expression, whereas inhibition of LPS by polymyxin B did not. The PG-induced expression of $TNF-{\alpha}$ was also significantly suppressed by pharmacological inhibitors that modulate activities of cellular signaling molecules; for example, U0126 (an ERK inhibitor), SB202190 (a p38 MAPK inhibitor), and SP6001250 (a JNK inhibitor) significantly attenuated PG-induced transcription of $TNF-{\alpha}$ and secretion of its gene product. $TNF-{\alpha}$ expression was also inhibited by rapamycin (an mTOR inhibitor), LY294002 (a PI3K inhibitor), and Akt inhibitor IV (an Akt inhibitor). ROS-regulating compounds, like NAC and DPI, also significantly attenuated $TNF{\alpha}$ expression induced by PG. These results suggest that PG induces $TNF-{\alpha}$ expression in monocytes/macrophages by multiple molecules, including TLR-2, PI3K, Akt, mTOR, MAPKs, and ROS.

• Journal of Surface Science and Engineering
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• v.26 no.6
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• pp.291-298
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• 1993

In order to substitute for porous nickel anode in Molten Carbonate Fuel Cell(MCFC), porous cermet elec-trode was fabricated with Ni and Ni-P coated ceramic powder. Ni and Ni-P were coated by electroless plat-ing method in the nickel solution containing of hydrazine and sodium hypophosphate as a reducing agent. The plating solution was stirred by air and mechanical agitator. Ultrasonic irradiation was applied to the plating bath to improved the effect of agitation and coating speed. Electorde was formed by pressing method and doc-tor blade method followed by sinterd at$ 800^{\circ}C$ for 6 hours in H2 environment. Anode performance test carried out by potentiodynamic polarization technique in the MCFC operating condition and 154-161mA/$\textrm{cm}^2$ as ob-tained as a anode current density at the+100mV overpotential.

• BMB Reports
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• v.49 no.8
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• pp.437-442
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• 2016

We aimed to study the role of protein L-isoaspartyl methyltransferase (PIMT) in neuronal differentiation using basic fibroblast growth factor (bFGF)-induced neuronal differentiation, characterized by cell-body shrinkage, long neurite outgrowth, and expression of neuronal differentiation markers light and medium neurofilaments (NF). The bFGF-mediated neuronal differentiation of PC12 cells was induced through activation of mitogen-activated protein kinase (MAPK) signaling molecules [MAPK kinase 1/2 (MEK1/2), extracellular signal-regulated kinase 1/2 (ERK1/2), and p90RSK], and phosphatidylinositide 3-kinase (PI3K)/Akt signaling molecules PI3Kp110β, PI3Kp110γ, Akt, and mTOR. Inhibitors (adenosine dialdehyde and S-adenosylhomocysteine) of protein methylation suppressed bFGF-mediated neuronal differentiation of PC12 cells. PIMT-eficiency caused by PIMT-specific siRNA inhibited neuronal differentiation of PC12 cells by suppressing phosphorylation of MEK1/2 and ERK1/2 in the MAPK signaling pathway and Akt and mTOR in the PI3K/Akt signaling pathway. Therefore, these results suggested that PIMT was critical for bFGF-mediated neuronal differentiation of PC12 cells and regulated the MAPK and Akt signaling pathways.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.8
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• pp.1079-1085
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• 2012

Obesity is an important issue worldwide as it may associated with increased prevalence of metabolic diseases. Mung bean is known as a functional food for decreasing the glycemic index and lipid profile of plasma. The purpose of this study was to investigate the anti-obesity effects of vitexin from mung bean on the regulation of adipocyte differentiation and adipocytokine secretion. When 3T3-L1 adipocytes were treated with vitexin from days 0 to 14 at various levels of 25, 50, 100, and $200{\mu}M$, there was no change in cell viability. Vitexin treatment at 50, 100, and $200{\mu}M$ decreased triacylglycerol levels in cells, but only $100{\mu}M$ vitexin induced lipolysis. At $200{\mu}M$ of vitexin, phosphorylation of p38 and ERK, which causes secretion of inflammatory adipocytokines, was depressed, whereas there was an increase in expression of $PPAR{\gamma}$, the key regulator of adipocyte differentiation. Phosphorylation of AMPK increased at $100{\mu}M$ vitexin. TNF-${\alpha}$ and aP2 mRNA expression increased at $25{\mu}M$ vitexin, whereas only TNF-${\alpha}$ mRNA expression increased at $200{\mu}M$ vitexin. Further, the mRNA levels of TNF-${\alpha}$ and aP2 decreased at other concentrations in a dose-dependent manner. Since we observed that mRNA expression of C/EBP, SREBP1, and $PPAR{\gamma}$ did not change upon vitexin treatment, our future studies will investigate other genes such as mTOR, which is related with apoptosis signaling, or SIRT1, which is associated with inhibition of adipogenesis. Our results indicate that vitexin at concentrations between 100 and $200{\mu}M$ is suitable in vivo for the development of mung bean as an anti-obesity therapy or functional food.

• Tuberculosis and Respiratory Diseases
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• v.75 no.1
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• pp.9-17
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• 2013

Background: In cancer cells, autophagy is generally induced as a pro-survival mechanism in response to treatment-associated genotoxic and metabolic stress. Thus, concurrent autophagy inhibition can be expected to have a synergistic effect with chemotherapy on cancer cell death. Monensin, a polyether antibiotic, is known as an autophagy inhibitor, which interferes with the fusion of autophagosome and lysosome. There have been a few reports of its effect in combination with anticancer drugs. We performed this study to investigate whether erlotinib, an epidermal growth factor receptor inhibitor, or rapamycin, an mammalian target of rapamycin (mTOR) inhibitor, is effective in combination therapy with monensin in non-small cell lung cancer cells. Methods: NCI-H1299 cells were treated with rapamycin or erlotinib, with or without monensin pretreatment, and then subjected to growth inhibition assay, apoptosis analysis by flow cytometry, and cell cycle analysis on the basis of the DNA contents histogram. Finally, a Western blot analysis was done to examine the changes of proteins related to apoptosis and cell cycle control. Results: Monensin synergistically increases growth inhibition and apoptosis induced by rapamycin or erlotinib. The number of cells in the sub-$G_1$ phase increases noticeably after the combination treatment. Increase of proapoptotic proteins, including bax, cleaved caspase 3, and cleaved poly(ADP-ribose) polymerase, and decrease of anti-apoptotic proteins, bcl-2 and bcl-xL, are augmented by the combination treatment with monensin. The promoters of cell cycle progression, notch3 and skp2, decrease and p21, a cyclin-dependent kinase inhibitor, accumulates within the cell during this process. Conclusion: Our findings suggest that concurrent autophagy inhibition could have a role in lung cancer treatment.

• Development and Reproduction
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• v.15 no.2
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• pp.179-185
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• 2011

Some phytoestrogens in soy and red wine, for example, might have beneficiary rather than adverse effects. In particular, dietary soy intake seems to be highly correlated with protection of breast cancer, osteoporosis and cardiovascular disorders. However, questions persist on the potential adverse effects of the main soy constituent genistein (GS) on female reproductive physiology. Previously we found that prepubertal exposure to GS could activate the reproductive system of immature female rats leading to precocious puberty onset, and intracerebroventricularly (ICV) injected GS could directly activate hypothalamic kisspeptin-GnRH neuronal circuits in adult female rats. The present study was performed to examine the hypothalamus-specific GS effects in prepubertal female rats and which subtype of estrogen receptor is mediated in this GS effect. Prepubertal female rats (PND 30) were anaesthetized, treated with single dose of GS (3.4 ${\mu}g$/animal), and sacrificed at 2 hrs post-injection. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus, total RNAs were extracted and applied to the semi-quantitative reverse transcription polymerase chain reaction (RT-PCR). ICV infusion of GS significantly lowered the transcriptional activities of mTOR (1:$0.361{\pm}0.058$ AU, p<0.001) but increased that of GAD67 (1:$1.285{\pm}0.099$ AU, p<0.05), which are known to act as an upstream modulator of kisspeptin and GnRH neuronal activities in the hypothalamus, respectively. GS administration enhanced significantly the mRNA levels of KiSS-1(1:$1.458{\pm}0.078$ AU, p<0.001), and exerted no effect on the mRNA level of kisspeptin receptor GPR-54 (1:$1.29{\pm}0.08$ AU). GnRH gene expression was significantly decreased in GS-treated group compared to control group (1:$0.379{\pm}0.196$ AU, p<0.05). There was no difference in the mRNA level of $ER{\alpha}$ in the GS-treated group compare to control group (1:$1.180{\pm}0.390$ AU, Fig. 3A). However, icv infusion of GS significantly increased the transcriptional activities of $ER{\beta}$ (1:$4.209{\pm}0.796$ AU, p<0.01, Fig. 3B). Taken together, the present study indicated that the acute exposure to GS could directly alter the hypothalamic GnRH modulating system in prepubertal female rats. Our study strongly suggested the involvement of $ER{\beta}$ pathway in GS's hypothalamus-specific action, and this idea is consistent with the GS's well-known $ER{\beta}$-mediated protective action in breast cancer.

• Journal of Life Science
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• v.33 no.3
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• pp.242-251
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• 2023

The purpose of this study was to investigate the effects of 8-week β-hydroxybutyrate (β-HB) administration with and without endurance exercise training on endurance exercise performance and skeletal muscle protein synthesis and degradation using a mouse model. Forty-eight male wild-type ICR mice (8 weeks old) were randomly divided into four groups: sedentary control (Sed+Con), (Sed+Con), sedentary β-HB (Sed+β-HB), exercise control (Exe+Con), and exercise β-HB (Exe+β-HB). β-HB was dissolved in PBS (150 mg/ml) and injected subcutaneously daily (250 mg/kg) for 8 weeks. Mice performed 5 days/week of a 20 min treadmill running exercise for 8 weeks. The running exercise was carried out at a speed of 10 m/min at a 10° incline for 5 min, and then the speed was increased by 1 m/min for every 1 min of the remaining 15 min. Following 8 weeks of treatments, visceral fat mass and skeletal muscle mass, blood parameters, and the markers for autophagy and protein synthesis were analyzed. The data were analyzed with one-way ANOVA (p<0.05) using the SPSS 21 program. Eight weeks of Exe+β-HB treatment significantly lowered blood lactate levels compared with the other three groups (Sed+Con, Sed+β-HB, and Exe+β-HB) Exe+β-HB) (p<0.05). Eight weeks of Exe+β-HB significantly increased maximal running time (time to exhaustion) compared with the Sed+Con and Exe+Con groups (p<0.05). Eight weeks of β-HB administration significantly decreased autophagy flux and autophagy-related proteins in the skeletal muscle of mice (p<0.05). Conversely, the combined treatment of β-HB and endurance exercise training increased protein synthesis (mTOR signaling and translation) (p<0.05). The 8-week β-HB treatment and endurance exercise training had synergistic effects on the increase in endurance performance, increase in protein synthesis, and decrease in protein degradation in the skeletal muscle of mice.

• BMB Reports
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• v.53 no.7
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• pp.373-378
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• 2020

Phosphorylation of the signaling component by protein kinase often leads to a kinase cascade or feedback loop. 3-Phosphoinositide-dependent kinase 1 (PDK1) signaling pathway diverges into various kinases including Akt and p70 S6 kinase (p70S6k). However, the PDK1 feedback mechanism remains elusive. Here, we demonstrated that UNC-51-like kinase (ULK1), an autophagy initiator kinase downstream of mechanistic target of rapamycin (mTOR), directly phosphorylated PDK1 on serine 389 at the linker region. Furthermore, our data showed that this phosphorylation affected the kinase activity of PDK1 toward downstream substrates. These results suggest a possible negative feedback loop between PDK1 and ULK1.