• Biomolecules & Therapeutics
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• 제19권1호
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• pp.21-26
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• 2011

Ceramide is an important lipid mediator of extracellular signals that control various cellular functions, including apoptosis. In this study, we showed that ceramide induced apoptosis in U373MG human glioblastoma cells associated with G1 cell cycle arrest. Treatment of cells with ceramide increased proapoptotic Bax expression and inhibited the expression of antiapoptotic Bcl-2 and Bcl-xL Ceramide also downregulated cyclin E, cyclin D1, cdk 2, and cdk4 which are involved in regulating cell cycle. In addition, ceramide suppressed phosphorylation of Akt, Bad, p70 S6 kinase, and 4E-BP1, suggesting the involvement of Akt/mTOR signaling pathway. Additionally, okadaic acid, an inhibitor of protein phosphatase 2A, partially blocked the ceramide mediated inhibition of phosphorylation of Akt and 4E-BP1. These results suggest that ceramide induces apoptosis in U373MG glioblastoma cells by regulating multiple signaling pathways that involve cell cycle arrest associated with Akt signaling pathway.

• 대한한방내과학회지
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• 제38권4호
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• pp.409-418
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• 2017

In Korea, Rhus verniciflua Stokes is used to purge hardness, alleviate blood stasis, and treat cancer. However, the mechanisms of related anti-cancer activity are not fully understood in human cancer cells. This study investigated the anti-cancer effects and mechanisms of Rhus verniciflua Stokes on MDA-MB-231 human breast cancer cells and found that treatment with a Rhus verniciflua Stokes extract resulted in time- and concentration-responses that indicated growth inhibition of breast cancer cells by induced apoptosis. This was followed by a decrease in mitochondrial membrane potential; the activation of caspase-3, -8, and -9; and the up-regulation of tBid. Caspase-dependent apoptosis was induced through the inhibition of phosphatidylinositol 3-kinase (PI3K) and the Akt signaling pathway. This study provides evidence that Rhus verniciflua Stokes might be useful for the treatment of breast cancer.

• 대한의생명과학회지
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• 제29권3호
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• pp.184-189
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• 2023

Normal activation of platelets and their aggregation are crucial during hemostasis process. It appears excessive or abnormal aggregation of platelets may bring about cardiovascular diseases like stroke, atherosclerosis, and thrombosis. For this reason, finding a substance that can regulate platelet aggregation or suppress aggregation will aid in the prevention and treatment of cardiovascular diseases. Artemisinin, a compound derived from Artemisia or Scopolia plants, has shown potential in various areas such as anticancer and Alzheimer's disease research. However, the specific role and mechanisms by which artemisinin influences platelet activation and thrombus formation are not yet fully understood. This study investigated the effects of artemisinin on platelet activation and thrombus formation. This study examined the effect of artemisinin on regulation of U46619-induced platelet aggregation, granule secretion. In addition, the effects of artemisinin on phosphorylation of PI3K/Akt and MAPK pathway involved in platelet aggregation was studied. As a result, artemisinin significantly downregulated of PI3K/Akt and MAPK pathway. In addition, artemisinin significantly reduced granule secretion, and platelet aggregation was inhibited by artemisinin. Therefore, we suggest that artemisinin is an anti-platelet substance that regulates PI3K/Akt and MAPK pathway and is valuable as a therapeutic and preventive agent for platelet-derived cardiovascular disease.

• The Korean Journal of Physiology and Pharmacology
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• 제16권5호
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• pp.361-365
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• 2012

Anti-tumor activity of the proteins from Gecko (GP) on cervical cancer cells, and its signaling mechanisms were assessed by viable cell counting, propidium iodide (PI) staining, and Western blot analysis. GP induced the cell death of HeLa cells in a dose-dependent manner while it did not affect the viability of normal cells. Western blot analysis showed that GP decreased the activation of Akt, and co-administration of GP and Akt inhibitors synergistically exerted anti-tumor activities on HeLa cells, suggesting the involvement of PI3-kinase/Akt pathway in GP-induced cell death of the cancer cells. Indeed, the cytotoxic effect of GP against HeLa cells was inhibited by overexpression of constituvely active form of Akt in HeLa cells. The candidates of the functional proteins in GP were analyzed by Mass-spectrum. Taken together, our results suggest that GP elicits anti-tumor activity against HeLa cells by inhibition of PI3-kinase/Akt pathway.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.4-11
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• 2020

Objective: Puerarin has the potential of regulating the differentiation of preadipocytes, but its mechanism of action has not yet been elucidated. Adipocytes found in adipose tissue, the main endocrine organ, are the main sites of lipid deposition, and are widely used as a cell model in the study of in vitro fat deposition. This study aimed to investigate the effects of puerarin on adipogenesis in vitro. Methods: Puerarin was added to the culture medium during the process of adipogenesis. The proliferation and differentiation of bovine preadipocytes was measured through cell viability and staining with oil red O. The content of triacylglycerol was measured using a triglyceride assay kit. The mRNA and protein expression levels of adipogenic genes, peroxisome proliferator-activated receptor-γ (PPARγ) and CCAAT/enhancer-binding protein-α, were measured using quantitative real-time polymerase chain reaction and western blotting, respectively. Results: The addition of puerarin significantly increased adipogenesis of bovine preadipocytes and enhanced the mRNA and protein level expression of PPARγ (p<0.01). The expression of P-Akt increased after adipogenic hormonal induction, whereas puerarin significantly increased PPARγ expression by promoting the Akt signaling component, P-Akt. The mechanism of adipogenesis was found to be related to the phosphorylation level of Ser473, which may activate the downstream signaling of the Akt pathway. Conclusion: Puerarin was able to promote the differentiation of preadipocytes and improve fat deposition in cattle. The mechanism of adipogenesis was found to be related to the phosphorylation level of Ser473.

• 구강회복응용과학지
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• 제36권3호
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• pp.145-157
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• 2020

목적: 본 연구에서는 구강연조직재생에서 인간치은섬유아세포에 hydrophobically modified glycol chitosan (HGC) 기반 나노방출제어시스템을 적용 시 PI3K-AKT 신호전달의 세포생존 연관 유전자를 통해 trichloroacetic acid (TCA)와 epidermal growth factor (EGF)의 영향을 확인하고자 하였다. 연구 재료 및 방법: TCA와 EGF를 방출하는 나노방출제어시스템을 제작하였다. 실험군은 3가지 군으로 나누었다; 대조군(CON), TCA-담지형 나노방출제어시스템 투여군(EXP1), TCA-와 EGF- 담지형 나노방출제어시스템 투여군(EXP2). 인간치은섬유아세포 배양 후 PI3K-AKT 신호전달에 연관된 총 29개 유전자를 실시간 중합효소연쇄반응으로 분석했다. 일요인 분산분석 및 다중회귀분석이 사용되었다. 결과: 세포생존 관련 유전자들은 EXP1과 EXP2에서 상향조절되었다. 다중회귀분석에서는 ITGB1이 AKT1의 발현에 가장 영향력 있는 요소로 결정되었다. 결론: HGC기반 나노방출제어시스템을 통한 TCA와 EGF의 적용은 세포생존에 관한 신호전달을 상향 조절시킬 수 있다.

• 약학회지
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• 제48권2호
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• pp.105-110
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• 2004

Akt (or Protein Kinase B; PKB) is a serine/threonine kinase and is activated by phosphoinositide 3-kinase (PI3K) pathway. Recent evidence indicates that the abnormal activities or expression of Akt is closely associated with cancer, diabetes and neuro-degenerative diseases. These findings mean that Akt is likely to be a new therapeutic target for the treatment of disease. Here, we screened the effects of dithiolo-dithione derivatives such as SWU-20004, SWU-20009 and SWU-20025 on Akt activities. Among these compounds, only SWU-20009 (2-Thioxo-[1,3]dithiolo[4,5- $\beta$][1,4]dithiine-5,6-dicarboxylic acid dimethyl ester) inhibited the growth of KATOIII cell at micromolar range of concentration. Further investigation also revealed that SWU-20009 inhibited cellular Akt activity and induced apoptotic cell death.

• 동의생리병리학회지
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• 제23권1호
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• pp.199-205
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• 2009

It is unclear whether Fructus ligustri Lucidi (FLL) extract anti-proliferative effect in human glioma cells. The present study was therefore undertaken to examine the effect of FLL on cell viability and to determine the underlying mechanism in A172 human glioma cells. Cell viability and cell death were estimated by MTT assay and trypan blue exclusion assay, respectively. Apoptosis was measured by Annexin-V binding assay and cell cycle analysis. Activation of kinases and caspase-3 was estimated by Western blot analysis. FLL resulted in apoptotic cell death in a dose- and time-dependent manner. FLL-induced cell death was not associated with reactive oxygen species generation. Western blot analysis showed that FLL treatment caused down-regulation of PI3K/Akt pathway, but not ERK. The PI3K/Akt inhibitor LY984002 sensitized the FLL-induced cell death and overexpression of Akt prevented the cell death. FLL induced caspase-3 activation and the FLL-induced cell death was prevented by caspase inhibitors. These findings indicate that FLL results in a caspase-dependent cell death through a P13K/Akt pathway in human glioma cells. These data suggest that FLL may serve as a potential therapeutic agent for malignant human gliomas.

• Journal of Cancer Prevention
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• 제21권3호
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• pp.135-143
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• 2016

Background: Fraxetin (7,8-dihydroxy-6-methoxy coumarin), a coumarin derivative, has been reported to possess antioxidative, anti-inflammatory and neuroprotective effects. A number of recent observations suggest that the induction of heme oxygenase-1 (HO-1) inhibits inflammation and tumorigenesis. In the present study, we determined the effect of fraxetin on HO-1 expression in HaCaT human keratinocytes and investigated its underlying molecular mechanisms. Methods: Reverse transcriptase-PCR and Western blot analysis were performed to detect HO-1 mRNA and protein expression, respectively. Cell viability was measured by the MTS test. The induction of intracellular reactive oxygen species (ROS) by fraxetin was evaluated by 2′,7′-dichlorofluorescin diacetate staining. Results: Fraxetin upregulated mRNA and protein expression of HO-1. Incubation with fraxetin induced the localization of nuclear factor-erythroid-2-related factor-2 (Nrf2) in the nucleus and increased the antioxidant response element-reporter gene activity. Fraxetin also induced the phosphorylation of Akt and AMP-activated protein kinase $(AMPK){\alpha}$ and diminished the expression of phosphatase and tensin homolog, a negative regulator of Akt. Pharmacological inhibition of Akt and $AMPK{\alpha}$ abrogated fraxetin-induced expression of HO-1 and nuclear localization of Nrf2. Furthermore, fraxetin generated ROS in a concentration-dependent manner. Conclusions: Fraxetin induces HO-1 expression through activation of Akt/Nrf2 or $AMPK{\alpha}/Nrf2$ pathway in HaCaT cells.

• Biomolecules & Therapeutics
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• 제31권3호
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• pp.276-284
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• 2023

Sinapic acid (SA) is a phenolic acid that is widely distributed in fruits and vegetables, which has various bioactivities, such as antidiabetic, anticancer and anti-inflammatory functions. Over-activated microglial is involved in the development progress of neurodegenerative diseases, such as Parkinson's disease and Alzheimer's disease. The objective of this study was to investigate the effect of SA in microglia neuroinflammation models. Our results demonstrated that SA inhibited secretion of the nitric oxide (NO) and interleukin (IL)-6, reduced the expression of inducible nitric oxide synthase (iNOS) and enhanced the release of IL-10 in a dose-dependent manner. Besides, our further investigation revealed that SA attenuated the phosphorylation of AKT and MAPK cascades in LPS-induced microglia. Consistently, oral administration of SA in mouse regulated the production of inflammation-related cytokines and also suppressed the phosphorylation of MAPK cascades and AKT in the mouse cerebral cortex. These results suggested that SA may be a possible therapy candidate for anti-inflammatory activity by targeting the AKT/MAPK signaling pathway.