• Biomolecules & Therapeutics
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• v.25 no.3
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• pp.315-320
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• 2017

We investigated the role of autophagy in SNUC5/5-FUR, 5-fluorouracil (5-FU) resistant SNUC5 colon cancer cells. SNUC5/5-FUR cells exhibited low level of autophagy, as determined by light microscopy, confocal microscopy, and flow cytometry following acridine orange staining, and the decreased level of GFP-LC3 puncta. In addition, expression of critical autophagic proteins such as Atg5, Beclin-1 and LC3-II and autophagic flux was diminished in SNUC5/5-FUR cells. Whereas production of reactive oxygen species (ROS) was significantly elevated in SNUC5/5-FUR cells, treatment with the ROS inhibitor N-acetyl cysteine further reduced the level of autophagy. Taken together, these results indicate that decreased autophagy is linked to 5-FU resistance in SNUC5 colon cancer cells.

• The Journal of Korean Medicine
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• v.40 no.2
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• pp.35-50
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• 2019

Objectives: Orostachys japonicas (O. japonicus) has been known for its anti-tumor effect. In the present study, it was investigated whether O. japonicus EtOH extracts could induce apoptosis and autophagy which are part of the main mechanism related to anti-tumor effect in THP-1 cells. Methods: Cells were treated with various concentrations of O. japonicus EtOH extracts ($0-300{\mu}g/ml$) for 24, 48, and 72h. Cell viability was evaluated by MTS/PMS assay and apoptosis rate was examined by flow cytometry and ELISA assay. The mRNA expression of apoptosis-related genes (Bcl-2, Mcl-1, Survivin, Bax) and autophagy-related gene (mTOR) was evaluated using real-time PCR. The protein expression of Caspase-3, Akt, LC3 II, Beclin-1, Atg5, $NF-{\kappa}B$, p38, ERK was evaluated using western blot analysis. Results: O. japonicus EtOH extracts inhibited cell proliferation and apoptosis rate was increased in both flow cytometry and ELISA assay. Bcl-2, Mcl-1, Survivin (anti-apoptosis factors) mRNA expressions were decreased and Bax (pro-apoptosis factor) mRNA level was increased. mTOR mRNA expressions was decreased and LC3 II protein expressions was increased. Activation of $NF-{\kappa}B$ was decreased and phosphorylation of p38 was increased. Conclusion: O. japonicus is regarded to inhibit cell proliferation, to induce apoptosis and to regulate autophagy-related genes in THP-1 cells via $NF-{\kappa}B$ and p38 MAPK signaling pathway. This suggests O. japonicus could be an effective herb in treating acute myeloid leukemia.

• Journal of Korean Neurosurgical Society
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• v.60 no.2
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• pp.130-137
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• 2017

Objective : Autophagy is one of the key responses of cells to programmed cell death. Memantine, an approved anti-dementia drug, has an antiproliferative effect on cancer cells but the mechanism is poorly understood. The aim of the present study was to test the possibility of induction of autophagic cell death by memantine in glioma cell lines. Methods : Glioma cell lines (T-98 G and U-251 MG) were used for this study. Results : The antiproliferative effect of memantine was shown on T-98 G cells, which expressed N-methyl-D-aspartate 1 receptor (NMDAR1). Memantine increased the autophagic-related proteins as the conversion ratio of light chain protein 3-II (LC3-II)-/LC3-I and the expression of beclin-1. Memantine also increased formation of autophagic vacuoles observed under a transmission electron microscope. Transfection of small interfering RNA (siRNA) to knock down NMDAR1 in the glioma cells induced resistance to memantine and decreased the LC3-II/LC3-I ratio in T-98 G cells. Conclusion : Our study demonstrates that in glioma cells, memantine inhibits proliferation and induces autophagy mediated by NMDAR1.

• Journal of Ginseng Research
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• v.44 no.1
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• pp.67-78
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• 2020

Background: Gintonin (GT), a novel ginseng-derived exogenous ligand of lysophosphatidic acid (LPA) receptors, has been shown to induce cell proliferation and migration in the hippocampus, regulate calcium-dependent ion channels in the astrocytes, and reduce β-amyloid plaque in the brain. However, whether GT influences autophagy in cortical astrocytes is not yet investigated. Methods: We examined the effect of GT on autophagy in primary cortical astrocytes using immunoblot and immunocytochemistry assays. Suppression of specific proteins was performed via siRNA. LC3 puncta was determined using confocal microscopy. Results: GT strongly upregulated autophagy marker LC3 by a concentration- as well as time-dependent manner via G protein-coupled LPA receptors. GT-induced autophagy was further confirmed by the formation of LC3 puncta. Interestingly, on pretreatment with an mammalian target of rapamycin (mTOR) inhibitor, rapamycin, GT further enhanced LC3-II and LC3 puncta expression. However, GT-induced autophagy was significantly attenuated by inhibition of autophagy by 3-methyladenine and knockdown Beclin-1, Atg5, and Atg7 gene expression. Importantly, when pretreated with a lysosomotropic agent, E-64d/peps A or bafilomycin A1, GT significantly increased the levels of LC3-II along with the formation of LC3 puncta. In addition, GT treatment enhanced autophagic flux, which led to an increase in lysosome-associated membrane protein 1 and degradation of ubiquitinated p62/SQSTM1. Conclusion: GT induces autophagy via mTOR-mediated pathway and elevates autophagic flux. This study demonstrates that GT can be used as an autophagy-inducing agent in cortical astrocytes.

• Journal of Periodontal and Implant Science
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• v.50 no.5
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• pp.291-302
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• 2020

Purpose: The objective of this study was to investigate whether phelligridin D could reduce glucose-induced oxidative stress, attenuate the resulting inflammatory response, and restore the function of human periodontal ligament cells (HPDLCs). Methods: Primary HPDLCs were isolated from healthy human teeth and cultured. To investigate the effect of phelligridin D on glucose-induced oxidative stress, HPDLCs were treated with phelligridin D, various concentrations of glucose, and glucose oxidase. Glucose-induced oxidative stress, inflammatory molecules, osteoblast differentiation, and mineralization of the HPDLCs were measured by hydrogen peroxide (H₂O₂) generation, cellular viability, alkaline phosphatase (ALP) activity, alizarin red staining, and western blot analyses. Results: Glucose-induced oxidative stress led to increased production of H₂O₂, with negative impacts on cellular viability, ALP activity, and calcium deposition in HPDLCs. Furthermore, HPDLCs under glucose-induced oxidative stress showed induction of inflammatory molecules (intercellular adhesion molecule-1, vascular cell adhesion protein-1, tumor necrosis factor-alpha, interleukin-1-beta) and disturbances of osteogenic differentiation (bone morphogenetic protein-2, and -7, runt-related transcription factor-2), cementogenesis (cementum protein-1), and autophagy-related molecules (autophagy related 5, light chain 3 I/II, beclin-1). Phelligridin D restored all these molecules and maintained the function of HPDLCs even under glucose-induced oxidative stress. Conclusions: This study suggests that phelligridin D reduces the inflammation that results from glucose-induced oxidative stress and restores the function of HPDLCs (e.g., osteoblast differentiation) by upregulating autophagy.

• International Journal of Oral Biology
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• v.41 no.1
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• pp.45-51
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• 2016

Rutin (3,3',4',5,7-pentahydroxyflavone-3-rhamnoglucoside) is a bioactive flavonoid from the plant kingdom. Rutin has been studied as potential anticancer agent due to its wide range of pharmacological properties including antioxidative, anti-inflammatory and anticancer. Autophagy is a conserved intracellular catabolic pathway to maintain cell homeostasis by formation of autophagosome. Processing of autophagy involves various molecules including ULK1 protein kinase complex, Beclin-1-Vps34 lipid kinase complex, ATG5, ATG12, and LC3 (light chain 3). Cargo-carried autophagosomes fuse with lysosomes resulting in autophagolysosome to eliminate vesicles and degrade cargo. However, the actions of rutin on autophagy are not clearly understood. In this study, we analyzed the effect of rutin on autophagy and inflammation in cancer cell lines. Interestingly, rutin induced autophagy in leukemia (THP-1), oral (CA9-22), and lung (A549) cell lines. TNF-${\alpha}$, key modulator of inflammation, was upregulated by inhibition of rutin-induced autophagy. Taken together, these data indicated that rutin induced autophagy and consequently suppressed TNF-${\alpha}$ production.

• Nutrition Research and Practice
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• v.14 no.5
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• pp.478-489
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• 2020

BACKGROUND/OBJECTIVES: Morusin, a marker component of Morus alba L., possesses anti-cancer activity. The objective of this study was to determine autophagy-inducing effect of morusin in non-small cell lung cancer (NSCLC) cells and investigate the underlying mechanism. SUBJECTS/METHODS: Autophagy induction and the expression of autophagy-related proteins were analyzed by LC3 immunofluorescence and western blot, respectively. The role of autophagy and AMP-activated protein kinase (AMPK) was determined by treating NSCLC cells with bafilomycin A1, an autophagy inhibitor, and compound C, an AMPK inhibitor. Cytotoxicity and apoptosis induction were determined by MTT assay, trypan blue exclusion assay, annexin V-propidium iodide (PI) double staining assay, and cell cycle analysis. RESULTS: Morusin increased the formation of LC3 puncta in the cytoplasm and upregulated the expression of autophagy-related 5 (Atg5), Atg12, beclin-1, and LC3II in NSCLC cells, demonstrating that morusin could induce autophagy. Treatment with bafilomycin A1 markedly reduced cell viability but increased proportions of sub-G1 phase cells and annexin V-positive cells in H460 cells. These results indicate that morusin can trigger autophagy in NSCLC cells as a defense mechanism against morusin-induced apoptosis. Furthermore, we found that AMPK and its downstream acetyl-CoA carboxylase (ACC) were phosphorylated, while mammalian target of rapamycin (mTOR) and its downstream p70S6 kinase (p70S6K) were dephosphorylated by morusin. Morusin-induced apoptosis was significantly increased by treatment with compound C in H460 cells. These results suggest that morusin-induced AMPK activation could protect NSCLC cells from apoptosis probably by inducing autophagy. CONCLUSIONS: Our findings suggest that combination treatment with morusin and autophagy inhibitor or AMPK inhibitor might enhance the clinical efficacy of morusin for NSCLC.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2018.10a
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• pp.101-101
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• 2018

Resveratrol is a polyphenolic compound, which is a naturally occurring phytochemical and is found in a variety of plants, including food such as grapes, berries and peanuts. Although several studies have demonstrated that resveratrol possesses anti-cancer activity against various types of human cancer, the molecular mechanisms of resveratrol-mediated overcome drug resistance potential are unclear. In this study, we determined whether resveratrol attenuates drug resistance responses in 5-fluorouracil-resistant colon cancer (SNUC5/5-FUR) cells. Treatment with resveratrol significantly enhanced apoptosis in a concentration-dependent manner, which was associated with the modulation of anti- and/or pro-apoptotic protein expression, activation of caspases and activation of AMP-activated protein kinase. Resveratrol treatment also increased the induction of autophagy through up-regulation of autophagy-related genes such as Microtubule-associated protein 1A/1B-light chain 3, P62 and beclin-1. However, blocking of autophagy by bafilomycin A1 reduced apoptotic cell death, suggesting that resveratrol-induced autophagy functions as a cell death mechanism in SNUC5/5-FU cells. Although the further studies are needed, these findings suggest that resveratrol may have therapeutic potential to overcome drug resistance in colon cancer patients.

• Biomolecules & Therapeutics
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• v.27 no.1
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• pp.117-125
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• 2019

Mebendazole (MBZ), a microtubule depolymerizing drug commonly used for the treatment of helminthic infections, has recently been noted as a repositioning candidate for angiogenesis inhibition and cancer therapy. However, the definite anti-angiogenic mechanism of MBZ remains unclear. In this study, we explored the inhibitory mechanism of MBZ in endothelial cells (ECs) and developed a novel strategy to improve its anti-angiogenic therapy. Treatment of ECs with MBZ led to inhibition of EC proliferation in a dose-dependent manner in several culture conditions in the presence of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF) or FBS, without selectivity of growth factors, although MBZ is known to inhibit VEGF receptor 2 kinase. Furthermore, MBZ inhibited EC migration and tube formation induced by either VEGF or bFGF. However, unexpectedly, treatment of MBZ did not affect FAK and ERK1/2 phosphorylation induced by these factors. Treatment with MBZ induced shrinking of ECs and caused G2-M arrest and apoptosis with an increased Sub-G1 fraction. In addition, increased levels of nuclear fragmentation, p53 expression, and active form of caspase 3 were observed. The marked induction of autophagy by MBZ was also noted. Interestingly, inhibition of autophagy through knocking down of Beclin1 or ATG5/7, or treatment with autophagy inhibitors such as 3-methyladenine and chloroquine resulted in marked enhancement of anti-proliferative and pro-apoptotic effects of MBZ in ECs. Consequently, we suggest that MBZ induces autophagy in ECs and that protective autophagy can be a novel target for enhancing the anti-angiogenic efficacy of MBZ in cancer treatment.

• International Journal of Oral Biology
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• v.46 no.1
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• pp.15-22
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• 2021

Alpha-lipoic acid (ALA) is a naturally occurring antioxidant and has been previously used to treat diabetes and cardiovascular disease. However, the autophagy effects of ALA against oxidative stress-induced dopaminergic neuronal cell injury remain unclear. The aim of this study was to investigate the role of ALA in autophagy and apoptosis against oxidative stress in the SH-SY5Y human dopaminergic neuronal cell line. We examined SH-SY5Y phenotypes using the 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide assay (cell viability/proliferation), 4′,6-diamidino-2-phenylindole dihydrochloride nuclear staining, Live/Dead cell assay, cellular reactive oxygen species (ROS) assay, immunoblotting, and immunocytochemistry. Our data showed ALA attenuated hydrogen peroxide (H2O2)-induced ROS generation and cell death. ALA effectively suppressed Bax up-regulation and Bcl-2 and Bcl-xL down-regulation. Furthermore, ALA increased the expression of the antioxidant enzyme, heme oxygenase-1. Moreover, the expression of Beclin-1 and LC-3 autophagy biomarkers was decreased by ALA in our cell model. Combined, these data suggest ALA protects human dopaminergic neuronal cells against H2O2-induced cell injury by inhibiting autophagy and apoptosis.