• Journal of Life Science
• /
• v.33 no.12
• /
• pp.967-977
• /
• 2023

Rubus crataegifolius (RC) is a traditional Asian medicinal plant belonging to the Rosaceae family. The fruits of RC are known to prevent adult diseases through antioxidants. In this study, the effects of RC extract (RCex) on obesity and nonalcoholic fatty liver disease (NAFLD) were evaluated in animal models. Twenty-eight male C57BL/6J mice were induced to become obese for 8 weeks and then the extract was orally administered for 8 weeks. RCex reduced body weight, adipose tissue, liver weight. RCex improved biochemical biomarkers including lipid metabolism (alanine aminotransferase (ALT), aspartate aminotransferase (AST), plasma triglyceride (TG), total cholesterol (TC), high-density lipoprotein (HDL) cholesterol and low-density lipoprotein (LDL) cholesterol). The activation of AMP-activated protein kinase (AMPK) reduced the expression of adipogenesis genes (liver × receptor (LXR), sterol regulatory element-binding protein-1c (SREBP-1c), fatty acid synthesis (FAS), acetyl-CoA carboxylase 1 (ACC1) and the effect of enhancing carnitine palmitoyltransferase (CPT) activity by RCex was verified. RCex also influence on plasma production of hormones (adiponectin & leptin) related on energy expenditure and metabolism. In addition, we confirmed that RCex improved glucose intolerance in HFD-induced obese rats. RCex was first demonstrated to have anti-obesity as well as anti-NAFLD effects by regulating fatty acid oxidation and fatty acid synthesis by phosphorylation of AMPK. This suggests that RCex could be a good supplement for the prevention of obesity and related NAFLD.

• Molecules and Cells
• /
• v.38 no.2
• /
• pp.138-144
• /
• 2015

Raloxifene is a selective estrogen receptor modulator (SERM) that binds to the estrogen receptor (ER), and exhibits potent anti-tumor and autophagy-inducing effects in breast cancer cells. However, the mechanism of raloxifene-induced cell death and autophagy is not well-established. So, we analyzed mechanism underlying death and autophagy induced by raloxifene in MCF-7 breast cancer cells. Treatment with raloxifene significantly induced death in MCF-7 cells. Raloxifene accumulated GFP-LC3 puncta and increased the level of autophagic marker proteins, such as LC3-II, BECN1, and ATG12-ATG5 conjugates, indicating activated autophagy. Raloxifene also increased autophagic flux indicators, the cleavage of GFP from GFP-LC3 and only red fluorescence-positive puncta in mRFP-GFP-LC3-expressing cells. An autophagy inhibitor, 3-methyladenine (3-MA), suppressed the level of LC3-II and blocked the formation of GFP-LC3 puncta. Moreover, siRNA targeting BECN1 markedly reversed cell death and the level of LC3-II increased by raloxifene. Besides, raloxifene-induced cell death was not related to cleavage of caspases-7, -9, and PARP. These results indicate that raloxifene activates autophagy-dependent cell death but not apoptosis. Interestingly, raloxifene decreased the level of intracellular adenosine triphosphate (ATP) and activated the AMPK/ULK1 pathway. However it was not suppressed the AKT/mTOR pathway. Addition of ATP decreased the phosphorylation of AMPK as well as the accumulation of LC3-II, finally attenuating raloxifene-induced cell death. Our current study demonstrates that raloxifene induces autophagy via the activation of AMPK by sensing decreases in ATP, and that the overactivation of autophagy promotes cell death and thereby mediates the anti-cancer effects of raloxifene in breast cancer cells.

• The Korean Journal of Physiology and Pharmacology
• /
• v.22 no.4
• /
• pp.379-389
• /
• 2018

A nucleobase adenine is a fundamental component of nucleic acids and adenine nucleotides. Various biological roles of adenine have been discovered. It is not produced from degradation of adenine nucleotides in mammals but produced mainly during polyamine synthesis by dividing cells. Anti-inflammatory roles of adenine have been supported in IgE-mediated allergic reactions, immunological functions of lymphocytes and dextran sodium sulfate-induced colitis. However adenine effects on Toll-like receptor 4 (TLR4)-mediated inflammation by lipopolysaccharide (LPS), a cell wall component of Gram negative bacteria, is not examined. Here we investigated anti-inflammatory roles of adenine in LPS-stimulated immune cells, including a macrophage cell line RAW264.7 and bone marrow derived mast cells (BMMCs) and peritoneal cells in mice. In RAW264.7 cells stimulated with LPS, adenine inhibited production of pro-inflammatory cytokines $TNF-{\alpha}$ and IL-6 and inflammatory lipid mediators, prostaglandin $E_2$ and leukotriene $B_4$. Adenine impeded signaling pathways eliciting production of these inflammatory mediators. It suppressed $I{\kappa}B$ phosphorylation, nuclear translocation of nuclear factor ${\kappa}B$ ($NF-{\kappa}B$), phosphorylation of Akt and mitogen activated protein kinases (MAPKs) JNK and ERK. Although adenine raised cellular AMP which could activate AMP-dependent protein kinase (AMPK), the enzyme activity was not enhanced. In BMMCs, adenine inhibited the LPS-induced production of $TNF-{\alpha}$, IL-6 and IL-13 and also hindered phosphorylation of $NF-{\kappa}B$ and Akt. In peritoneal cavity, adenine suppressed the LPS-induced production of $TNF-{\alpha}$ and IL-6 by peritoneal cells in mice. These results show that adenine attenuates the LPS-induced inflammatory reactions.

• Journal of Life Science
• /
• v.23 no.5
• /
• pp.689-697
• /
• 2013

In the United States, about 40,000 new cases of oral cancer are diagnosed each year and nearly 7,800 patients died from it in 2012. Omega-3 polyunsaturated fatty acids have been found to have anticancer effects in a variety of cancer cell lines and animal models, but their effect in oral cancer remains unclear. This study was designed to examine the effect of docosahexaenoic acid (DHA, a kind of omega-3 fatty acid) on oral cancer cells and the molecular mechanism of its action. We found that exposure of squamous cell carcinoma-4 (SCC-4) and squamous cell carcinoma-9 (SCC-9) human oral cancer cells to DHA induced growth inhibition in a dose- and time-dependent manner. Meanwhile, in addition to the elevated levels of apoptotic markers, such as cleaved PARP, subG1 portion and TUNEL-positive nuclei, DHA led to autophagic vesicle formation and an increase in autophagic flux, indicating the involvement of both apoptosis and autophagy in the inhibitory effects of DHA on oral cancer cells. Further experiments revealed that the apoptosis and autophagy induced by DHA were linked to inhibition of mammalian target of rapamycin (mTOR) signaling by AKT inhibition and AMP-activated protein kinase (AMPK) activation in SCC-9 cells. Together, our results suggest that DHA induces apoptosis- and autophagy-associated cell death through the AMPK/AKT/mTOR signaling pathway in oral cancer cells. Thus, utilization of omega-3 fatty acids may represent a promising therapeutic approach for chemoprevention and treatment of human oral cancer.

• Natural Product Sciences
• /
• v.25 no.4
• /
• pp.298-303
• /
• 2019

This study investigated the cytotoxic effects and mechanism of action of asiatic acid in pancreatic cancer cell lines. First, we confirmed the cell viability of MIA PaCa-2 and PANC-1 cells after asiatic acid administration for 48 and 72 h. The viability of MIA PaCa-2 and PANC-1 cells decreased in a dose-dependent manner following asiatic acid administration. To investigate the underlying mechanism, we performed a terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL) assay, annexin V assay, and western blotting. Asiatic acid induced apoptosis and autophagy through activation of AMP-activated protein kinase (AMPK) and inhibition of mammalian target of rapamycin (mTOR) in MIA PaCa-2 cells. Finally, the expression of miR-17 and miR-21, known as oncogenes in pancreatic cancer, was decreased by asiatic acid. These results indicate that asiatic acid has potential as a new therapeutic agent against pancreatic cancer.

• Journal of Life Science
• /
• v.30 no.10
• /
• pp.835-843
• /
• 2020

Obesity, the world's leading metabolic disease, is a serious health problem in both industrialized and developing countries. Natural substances are of great interest in preventative medicine, especially in the field of metabolic syndromes-from insulin resistance to obesity and diabetes. In the present study, we investigated the effect of A. pullulans SM-2001 Extract (Polycan^®) on the adipocyte differentiation of 3T3-L1 preadipocytes and the anti-obesity effect of 3T3-L1 adipocytes. Although β-glucan has been found to have health benefits in the regulation of the immune system and blood cholesterol levels, its role in obesity has not been fully investigated. Polycan^® suppressed lipid accumulation and glycerol-3-phosphate dehydrogenase (GPDH) activity without affecting cell viability in 3T3-L1 preadipocytes and adipocytes. Polycan^® also inhibited cellular lipid accumulation through down-regulation of transcription factors, such as PPARγ and C/EBPα, and induced dose-dependent phosphorylation of AMP-activated protein kinase (AMPK)-a cellular energy sensor-while the total AMPK protein content remained unchanged. Taken together, this shows that the activation of AMPK by Polycan^® in adipocytes plays a critical role in Polycan^®-induced inhibition of adipocyte differentiation. Our results show that Polycan^® has an anti-obesity action in vitro, suggesting a potential novel preventative agent for obesity and other metabolic diseases.

• Journal of Life Science
• /
• v.27 no.2
• /
• pp.155-163
• /
• 2017

Mori Folium, the leaf of Morus alba, is a traditional medicinal herb that shows various pharmacological activities such as antiinflammatory, antidiabetic, antimelanogenesis, antioxidant, antibacterial, antiallergic, and immunomodulatory activities. However, the mechanisms of their inhibitory effects on adipocyte differentiation and adipogenesis remain poorly understood. In the present study, we investigated the inhibition of adipocyte differentiation and adipogenesis by ethanol extracts of Mori Folium (EEMF) in 3T3-L1 preadipocytes. Treatment with EEMF suppressed the terminal differentiation of 3T3-L1 preadipocytes in a dose-dependent manner, as confirmed by a decrease in the lipid droplet number and lipid content through Oil Red O staining. EEMF significantly reduced the accumulation of cellular triglyceride, which is associated with a significant inhibition of pro-adipogenic transcription factors, including sterol regulatory element-binding protein-1c (SREBP-1c), peroxisome proliferator-activated receptor-${\gamma}$ ($PPAR{\gamma}$), and CCAAT/enhancer-binding proteins ${\alpha}$ ($C/EBP{\alpha}$) and ${\beta}$ ($C/EBP{\beta}$). In addition, EEMF potentially downregulated the expression of adipocyte-specific genes, including adipocyte fatty acid binding protein (aP2) and leptin. Furthermore, EEMF treatment effectively increased the phosphorylation of the AMP-activated protein kinase (AMPK) and acetyl CoA carboxylase (ACC); however, treatment with a potent inhibitor of AMPK, compound C, significantly restored the EEMF-induced inhibition of pro-adipogenic transcription factors and adipocyte-specific genes. These results together indicate that EEMF has preeminent effects on the inhibition of adipogenesis through the AMPK signaling pathway, and further studies will be needed to identify the active compounds in Mori Folium.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.43 no.11
• /
• pp.1681-1687
• /
• 2014

In the present study, we investigated the effect of ethyl acetate fraction from 50% ethanol extract of fermented Curcuma longa L. (FCEE) on lipid metabolism in 3T3-L1 cells. The safety range of FCEE was up to $300{\mu}g/mL$. Effects of FCEE on lipid accumulation and intracellular triglyceride (TG) content in 3T3-L1 cells were examined by Oil Red O staining and AdipoRed assay. Compared to adipocytes, lipid accumulation and intracellular TG content were significantly reduced by 10.2% and 13.7%, respectively, upon FCEE treatment at a concentration of $200{\mu}g/mL$. Glucose uptake by 3T3-L1 cells was significantly reduced by 36.6% compared to adipocytes at a concentration of $200{\mu}g/mL$. On day 8, free glycerol release into the culture medium was significantly reduced compared to adipocytes at concentrations of 50, 100, and $200{\mu}g/mL$ of FCEE. FCEE significantly stimulated RNA expression of AMP-activated protein kinase (AMPK) and suppressed mRNA expressions of sterol regulatory element-binding protein-1c (SREBP-1c), CCAAT/enhancer binding proteins ${\alpha}$ ($C/EBP{\alpha}$), and peroxisome proliferator- activated receptor ${\gamma}$ ($PPAR{\gamma}$) in 3T3-L1 cells. These results suggest that FCEE inhibits adipogenesis through activation of AMPK mRNA expressions and inhibition of SREBP-1c, $C/EBP{\alpha}$, and $PPAR{\gamma}$ mRNA expressions.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.27 no.6
• /
• pp.802-808
• /
• 2013

Here we tried to uncover the potential anti-lipogenic effect and the underlying mechanism of Phaseolus angularis seed in a cellular model of nonalcoholic fatty liver disease (NAFLD) induced in HepG2 cells. Ethanol extract of Phaseolus angularis seed (JSD) was prepared. HepG2 cells were incubated in palmitate containing media to induce intracellular lipid accumulation, and co-treated with JSD for 16 hrs before examine intracellular lipid content. In control group, the cells were not co-treated with JSD. We measured the effects of JSD on liver X receptor ${\alpha}$ ($LXR{\alpha}$) and sterol regulatory element-binding transcription factor-1c (SREBP-1c) expression, transcription level of lipogenic genes, including acetyl-CoA carboxylase (ACC), fatty acid synthase (FAS), stearoyl-CoA desaturase-1 (SCD-1), and AMP-activated protein kinase (AMPK) activation in HepG2 cells. JSD markedly reduced palmitate-induced intracellular lipid accumulation in HepG2 cells. JSD suppressed $LXR{\alpha}$/SREBP-1c expression, and SREBP-1c mediated induction of ACC, FAS, and SCD-1. Furthermore, JSD activated AMPK, which plays a major role in the control of hepatic lipid metabolism. Taken together, it is suggested that JSD has a potential to alleviate hepatic steatosis, at least in part, by suppressing $LXR{\alpha}$/SREBP-1c mediated induction of lipogenic genes. In addtion, the anti-lipogenic potential may be associated with activation of AMPK. Therefore, the Phaseolus angularis seed could be applied as a potential therapeutics for NAFLD with additional clinical studies.

• Herbal Formula Science
• /
• v.23 no.2
• /
• pp.189-198
• /
• 2015

Objectives : Sparganii Rhizoma is frequently used in traditional herbal medicine for treatment of blood stasis, amenorrhea and functional dyspepsia and has been reported to exhibit anti-oxidant, anti-proliferation and anti-angiogenesis peoperties. In this study, we investigated the cytoprotective effect and underlying mechanism of Sparganii Rhizoma water extract (SRE) against oxidative stress-induced mitochondrial dysfunction and apoptosis in hepatocyte. Methods : To determine the effects of SRE on oxidative stress, we induced synergistic cytotoxicity by co-treatment of arachidonic acid (AA) and iron in the HepG2 cell, a human derived hepatocyte cell line. Results : Treatment of SRE increased relative cell viability and altered the expression levels of apoptosis-related proteins such as Bcl-xL, Bcl-2 and procaspase-3. And SRE also inhibited the mitochondrial dysfunction and excessive reactive oxygen species production induced by AA+iron. In addition, SRE activated of AMP-activated protein kinase (AMPK), a potential target for cytoprotection, by increasing the phosphorylation of AMPKα at Thr-172. Morever, SRE increased phosphorylation of acetyl-CoA carboxylase, a direct downstream target of AMPK. Conclusion : These results indicated that SRE has the ability to protect against oxidative stress-induced hepatocyte damage, which may be mediated with AMPK pathway.