• International Journal of Oral Biology
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• v.46 no.1
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• pp.23-29
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• 2021

Demethoxycurcumin (DMC), which is a curcuminoid found in turmeric, has anti-proliferative effects on cancer cells. However, the effect of DMC on osteosarcoma has not been established. The aim of this study was to examine the effects of DMC on cell growth and apoptosis induction in MG-63 human osteosarcoma cells. This study was investigated using 3-[4, 5-dimethylthiazol-2-yl]-2, 5 diphenyl tetrazolium bromid assay, Live/Dead cell assay, 4', 6-diamidino-2-phenylindole staining, and immunoblotting in MG-63 cells. DMC induced MG-63 cell death in a dose-dependent manner, with an estimated IC50 value of 54.4 µM. DMC treatment resulted in nuclear condensation in MG-63 cells. DMC-induced apoptosis in MG-63 cells was mediated by the expression of Fas and activation of caspase-8, caspase-3, and poly (ADP-ribose) polymerase. Immunoblotting results showed that Bcl-2 and Bcl-xL were downregulated, while Bax and Bad were upregulated by DMC in MG-63 cells. These results indicated that DMC inhibits cell proliferation and induces apoptotic cell death in MG-63 human osteosarcoma cells via the death receptor-mediated extrinsic apoptotic pathway and mitochondria-mediated intrinsic apoptotic pathway.

• Proceedings of the Korean Society of Life Science Conference
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• 2007.10a
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• pp.84.2-84.2
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• 2007

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• BMB Reports
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• v.52 no.11
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• pp.665-670
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• 2019

Nucleotide-binding oligomerization domain protein 2 (NOD2), an intracellular pattern recognition receptor, plays important roles in inflammation and cell death. Previously, we have shown that NOD2 is expressed in vascular smooth muscle cells (VSMCs) and that NOD2 deficiency promotes VSMC proliferation, migration, and neointimal formation after vascular injury. However, its role in endoplasmic reticulum (ER) stress-induced cell death in VSMCs remains unclear. Thus, the objective of this study was to evaluate ER stress-induced viability of mouse primary VSMCs. NOD2 deficiency increased ER stress-induced cell death and expression levels of apoptosis mediators (cleaved caspase-3, Bax, and Bak) in VSMCs in the presence of tunicamycin (TM), an ER stress inducer. In contrast, ER stress-induced cell death and expression levels of apoptosis mediators (cleaved caspase-3, Bax, and Bak) were decreased in NOD2-overexpressed VSMCs. We found that the $IRE-1{\alpha}-XBP1$ pathway, one of unfolded protein response branches, was decreased in NOD2-deficient VSMCs and reversed in NOD2-overexpressed VSMCs in the presence of TM. Furthermore, NOD2 deficiency reduced the expression of XBP1 target genes such as GRP78, PDI-1, and Herpud1, thus improving cell survival. Taken together, these data suggest that the induction of ER stress through NOD2 expression can protect against TM-induced cell death in VSMCs. These results may contribute to a new paradigm in vascular homeostasis.

• Journal of Life Science
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• v.25 no.11
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• pp.1235-1243
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• 2015

Hwangheuk-san (HHS) is a Korean multi-herb formula comprising four medicinal herbs. HHS, which was recorded in “Dongeuibogam,” has been used to treat patients with inflammation syndromes and digestive tract cancer for hundreds of years. However, little is known about its anti-tumor efficacy. The present study investigated the pro-apoptotic effect and mode of action of HHS against AGS human gastric carcinoma cells. HHS inhibited the cell growth of AGS cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies, chromatin condensation, and an accumulation of cells in the sub-G1 phase. HHS-induced apoptotic cell death was associated with the up-regulation of pro-apoptotic Bax protein expression, down-regulation of antiapoptotic Bcl-2 protein, and the release of cytochrome c from mitochondria to the cytosol. The treatment of AGS cells with HHS significantly elevated the generation of reactive oxygen species (ROS). Additionally, apoptosis-inducing concentrations of HHS induced the activation of both caspase-9 and -8, initiator caspases of the mitochondrial-mediated intrinsic and death receptor-mediated extrinsic pathways, respectively, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. However, ROS scavenger and pan-caspases inhibitor significantly blocked HHS-induced growth inhibition and apoptosis. Taken together, these findings suggest that HHS induces apoptosis through ROS- and caspase-dependent mechanisms and that HHS may be a potential chemotherapeutic agent for the control of human gastric cancer.

• Journal of Life Science
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• v.25 no.11
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• pp.1255-1264
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• 2015

Cnidium officinale, a traditional herb, has diverse beneficial pharmacological activities, such as anti-inflammatory, antioxidant, anticancer, and antiangiogenesis effects. However, the cellular and molecular mechanisms of apoptosis by C. officinale are poorly defined. The present study investigated the proapoptotic effects of water, ethanol, and methanol extract of C. officinale (WECO, EECO, and MECO, respectively) in human leukemia U937 cells. The antiproliferative activity of EECO was higher than that of WECO and MECO. The antiproliferative effect of EECO treatment in U937 cells was associated with the induction of apoptotic cell death, including increased populations of annexin-V positive cells, the formation of apoptotic bodies, DNA fragmentation, and increased numbers of cells with a loss of mitochondrial membrane potential (MMP, Δψm). EECO-induced apoptotic cell death was associated with upregulation of death receptor 4 (DR4) and down-regulation of cellular inhibitor of apoptosis protein-1 (cIAP-1), Bcl-2, and total Bid. The EECO treatment also induced the proteolytic activation of caspases (-3, -8, and -9), and degradation of caspase-3 substrate proteins, such as poly(ADP-ribose) polymerase (PARP), β-catenin, and phospholipase C-γ1 (PLCγ1). In addition, the EECO treatment effectively activated the adenosine monophosphate-activated protein kinase (AMPK) signaling pathway. However, compound C, a specific inhibitor of AMPK, significantly reduced EECO-induced apoptosis. These results indicate that AMPK is a key regulator of apoptosis in response to EECO in human leukemia U937 cells.

• Journal of Life Science
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• v.25 no.1
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• pp.93-100
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• 2015

Pachymic acid (PA) is a lanostane-type triterpenoid derived from the Poria cocos mushroom. Several beneficial biological features of PA provide medicine with a wide variety of valuable effects, such as anticancer and anti-inflammatory activity; it also has antioxidant effects against oxidative stress. Nonetheless, the biological properties and mechanisms that produce this anti-cancer action of PA remain largely undetermined. In this study, we investigated the pro-apoptotic effects of PA in T24 human bladder cancer cells. It was found that PA could inhibit the cell growth of T24 cells in a dose-dependent manner, which was associated with the induction of apoptotic cell death, as evidenced by the formation of apoptotic bodies and chromatin condensation and accumulation of cells in the sub-G1 phase. The induction of apoptotic cell death by PA was connected with an up-regulation of pro-apoptotic Bax and Bad protein expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, and inhibition of apoptosis family proteins. In addition, apoptosis-inducing concentrations of PA induced the activation of caspase-9, an initiator caspase of the mitochondrial-mediated intrinsic pathway, and caspase-3, accompanied by proteolytic degradation of poly (ADP-ribose)-polymerase. PA also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the truncation of Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that PA may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Journal of Life Science
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• v.25 no.2
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• pp.249-255
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• 2015

Schisandrae fructus [Schizandra chinensis (Turcz.) Baillon] is a medicinal herb widely used for treating various inflammatory and immune diseases in East Asian countries. The Schisandrae Semen essential oil (SSeo) from this plant has pharmacological activities, including antioxidant, antimicrobial, and antitumoral activities. Nevertheless, the biological activities and underlying molecular mechanisms of the potential anti-cancer effects of this oil remain unclear. In the present study, we investigated the potential inhibition of apoptosis signaling pathways by SSeo in human leukemia U937 cells and evaluated the underlying molecular mechanism. Exposure to SSeo resulted in a concentration-dependent growth inhibition due to apoptosis, which was verified by DNA fragmentation, the presence of apoptotic bodies, and an increase in the sub-G1 ratio. Induction of apoptotic cell death by SSeo was correlated with the down-regulation of members of the inhibitor of apoptosis protein (IAP) family (including X-linked inhibitor of apoptosis protein (XIAP), cIAP-1, and surviving) and anti-apoptotic Bcl-2, and with up-regulation of death receptor (DR) 4 and DR5, depending on dosage. SSeo treatment also induced Bid truncation, mitochondrial dysfunction, proteolytic activation of caspase-3, -8 and -9, and concomitant degradation of activated caspase-3 target proteins such as poly (ADP-ribose) polymerase. Taken together, these findings suggest that SSeo may be a potential chemotherapeutic agent for use in the control of human leukemia cells. Further studies are needed to identify its active compounds.

• Journal of Life Science
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• v.24 no.12
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• pp.1356-1363
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• 2014

Ghrelin is a 28 amino acid orexigenic peptide hormone that is secreted predominantly by tX/A cells in the stomach, and it plays a major role in energy homeostasis. Activated ghrelin has an n-octanoyl group covalently linked to the hydroxyl group of the Ser3 residue, which is critical for its binding to the G-protein coupled growth hormone secretagogue receptor-1a (GHS-R1a). According to recent reports, both ghrelin and its receptor, GHS-R1a, are expressed by a variety of immune cells, including T- and B-lymphocytes, monocytes, and dendritic cells, and ghrelin stimulation of leukocytes provides a potent immunomodulatory signal controlling systemic and age-associated inflammation and thymic involution. Here, we report that ghrelin protected murine thymocytes from dexamethasone (DEX)-induced cell death both in vivo and in vitro. Subsequently, we explored the molecular mechanisms of the antiapoptotic effect of ghrelin. According to our experiments, ghrelin inhibited the expression of proapoptotic proteins via the regulation of glucocorticoid receptor (GR) phosphorylation. As a result, ghrelin inhibited the proapoptotic activation of proteins, such as Caspase-3, PARP, and Bim. These data suggest that ghrelin, through GHS-R, inhibits the pathway to apoptosis by regulation of the proapoptotic protein activation signal pathway. They provide evidence that blocking apoptosis is an essential function of ghrelin during the development of thymocytes.

• Molecules and Cells
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• v.26 no.2
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• pp.165-170
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• 2008

Procaspase-8 is activated by forming a death-inducing signaling complex (DISC) with the Fas-associated death domain (FADD) and the Fas receptor, but the mechanism of its activation is not well understood. Procaspase-8 devoid of the death effector domain at its N-terminus (${\Delta}nprocaspase-8$) was reported to be activated by kosmotropic salts, but it has not been induced to form a DISC in vitro because it cannot interact with FADD. Here, we report the production of full-length procaspase-8 and show that it is activated by adding the Fas death domain (Fas-DD) and the FADD forming the cytoplasmic part of the DISC (cDISC). Furthermore, mutations known to affect DISC formation in vivo were shown to have the same effect on procaspase-8 activation in vitro. An antibody that induces Fas-DD association enhanced procaspase-8 activation, suggesting that the Fas ligand is not required for low-level activation of procaspase-8, but that Fas receptor clustering is needed for high-level activation of procaspase-8 leading to cell death. In vitro activation of procaspase-8 by forming a cDISC will be invaluable for investigating activation of ligand-mediated apoptosis and the numerous interactions affecting procaspase-8 activation.

• Journal of Animal Reproduction and Biotechnology
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• v.36 no.3
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• pp.145-153
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• 2021

The role of transient receptor potential vanilloid receptor-1 (TRPV1) has been primarily investigated in pain sensory neurons. Relatively, little research has been performed in testicular cells. TRPV1 is abundantly expressed in Leydig cells of young adult mice. This study was conducted to determine the role of the TRPV1 channel in Leydig cells. TRPV1 modulators and testosterone were treated to the mouse Leydig cell line TM3 cells for 24 h. Capsaicin, a TRPV1 activator, dose-dependently induced cell death, whereas capsazepine, a TRPV1 inhibitor, inhibited capsaicin-induced cell death. Testosterone treatment reduced capsaicin-induced cell death. High concentrations of testosterone decreased TRPV1 mRNA and protein expression levels. However, TRPV1 modulators did not affect testosterone production. These results showed that capsaicin induced cell death of Leydig cells and that testosterone reduced capsaicin-induced cell death. Our findings suggest that testosterone may regulate the survival of Leydig cells in young adult mice by decreasing the expression level of TRPV1.