• Journal of Physiology & Pathology in Korean Medicine
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• v.29 no.1
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• pp.18-26
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• 2015

Akebiae Caulis is a galenical originated from Akebia quinata Decaisne species. It is commonly used in the treatment of oposiuria, inflammation, nociceptive and fever. Here, we investigated the effect of Akebiae Caulis extract (ACE) to protect hepatocyte against the malfunction of mitochondria and apoptosis. Arachidonic acid (AA)+iron promoted excessive reactive oxygen species (ROS) production and exerted a deleterious effect on mitochondria. Treatment with ACE protected hepatocytes from AA+iron-induced cytotoxicity, as shown by alterations in the protein levels related with apoptosis such as poly(ADP-ribose) polymerase, pro-caspase 3, Bcl-XL and Bcl-2. Moreover, AA+iron-induced $H_2O_2$ production, GSH depletion and mitochondrial dysfunction were alleviated by ACE pretreatment. As a potential molecular mechanism for the ACE-mediated cytoprotection, phosphorylation of AMP-activated protein kinase (AMPK), a key regulator in determining cell survival or death, was increased by ACE. Moreover, ACE treatment enhanced inactive phosphorylation of glycogen synthase kinase-$3{\beta}$ ($GSK3{\beta}$), downstream substrate kinase of AMPK. More importantly, ACE prevented a decrease in the $GSK3{\beta}$ phosphorylation derived by AA+iron, which might contribute to mitohondiral protection and cell survival. To further identify essential compounds in Akebiae Caulis for the protection of AA+iron-mediated cytotoxicity, we found that betulin in combination with hederagenin protected from AA+iron-induced mitochondrial dysfunction. Betulin+hederagenin treatment also increased inactive phosphorylation of $GSK3{\beta}$ in common with ACE. These results suggest that ACE protected hepatocytes against oxidative stress and mitochondrial dysfunction, which is mediated with inactive $GSK3{\beta}$ phosphorylation downstream of AMPK.

• Biomolecules & Therapeutics
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• v.28 no.5
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• pp.443-455
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• 2020

The thioredoxin (Trx) system plays critical roles in regulating intracellular redox levels and defending organisms against oxidative stress. Recent studies indicated that Trx reductase (TrxR) was overexpressed in various types of human cancer cells indicating that the Trx-TrxR system may be a potential target for anti-cancer drug development. This study investigated the synergistic effect of auranofin, a TrxR-specific inhibitor, on sulforaphane-mediated apoptotic cell death using Hep3B cells. The results showed that sulforaphane significantly enhanced auranofin-induced apoptosis by inhibiting TrxR activity and cell proliferation compared to either single treatment. The synergistic effect of sulforaphane and auranofin on apoptosis was evidenced by an increased annexin-V-positive cells and Sub-G1 cells. The induction of apoptosis by the combined treatment caused the loss of mitochondrial membrane potential (ΔΨm) and upregulation of Bax. In addition, the proteolytic activities of caspases (-3, -8, and -9) and the degradation of poly (ADP-ribose) polymerase, a substrate protein of activated caspase-3, were also higher in the combined treatment. Moreover, combined treatment induced excessive generation of reactive oxygen species (ROS). However, treatment with N-acetyl-L-cysteine, a ROS scavenger, reduced combined treatment-induced ROS production and apoptosis. Thereby, these results deduce that ROS played a pivotal role in apoptosis induced by auranofin and sulforaphane. Furthermore, apoptosis induced by auranofin and sulforaphane was significantly increased through inhibition of the phosphoinositide 3-kinase (PI3K)/Akt pathway. Taken together, the present study demonstrated that down-regulation of TrxR activity contributed to the synergistic effect of auranofin and sulforaphane on apoptosis through ROS production and inhibition of PI3K/Akt signaling pathway.

• Journal of Life Science
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• v.26 no.2
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• pp.241-246
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• 2016

In the present study, ethanol extracts and their subsequent organic solvent fractions were extracted from the lees of Ehwa Makgeolli containing oriental herbs, a commercialized traditional Korean rice wine, and the prepared lees samples were designated as from KSD-E3-1 to KSD-E3-5. First, their effects on cell viability and on the expression of pro-apoptotic ATF3 and NAG-1 genes in human colorectal HCT116 cells were investigated. Among the treated lees samples, the hexane fraction (KSD-E3-2) and the ethyl acetate fraction (KSD-E3-3) of lees extracts from Ehwa Makgeolli significantly reduced cell viabilities, in a dose dependent manner. The treatment with KSD-E3-2 and KSD-E3-3 also increased the expression of pro-apoptotic NAG-1 and ATF-3 genes and their proteins, which were detected with RT-PCR and Western blot analysis, respectively. In addition, poly-(ADP-ribose) polymerase (PARP) cleavage was detected by treatment with the fraction KSD-E3-3, indicating that KSD-E3-3 could induce apoptosis in HCT116 cells. Interestingly, this PARP cleavage was recovered by transfection of NAG-1 small interfering RNA. The results indicate that NAG-1 is one of the genes responsible for apoptosis induced by the fraction KSD-E3-3 from Ehwa Makgeolli. Overall, the findings may help in understanding the molecular mechanisms of the anti-proliferative and pro-apoptotic activities mediated by the lees of Ehwa Makgeolli.

• Journal of Life Science
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• v.26 no.7
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• pp.847-854
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• 2016

Cordycepin, a derivative of the nucleoside adenosine, is one of the active components extracted from fungi of genus Cordyceps, and has been shown to have many pharmacological activities. In this study, we investigated the effects of cordycepin on proliferation and apoptosis of human gastric cancer AGS cells, and its possible mechanism of action. Treatment of cordycepin resulted in significant decrease in cell viability of AGS cells in a concentration-dependent manner. A concentration-dependent apoptotic cell death was also measured by agarose gel electrophoresis and flow cytometery analysis. Molecular mechanistic studies of apoptosis unraveled cordycepin treatment resulted in an enhanced expression of tumor necrosis factor-related apoptosis-inducing ligand, death receptor 5 and Fas ligand. Furthermore, up-regulation of pro-apoptotic Bax, and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL expression were also observed in cordycepin-treated AGS cells. These were followed by activation of caspases (caspase-9, -8 and -3), subsequently leading to poly (ADP-ribose) polymerase cleavage. Taken together, these findings indicate that cordycepin induces apoptosis in AGS cells through regulation of multiple apoptotic pathways, including death receptor and mitochondria. Although further mechanical studies are needed, our results revealed that cordycepin can be regarded as a new effective and chemopreventive compound for human gastric cancer treatment.

• Proceedings of the Plant Resources Society of Korea Conference
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• 2019.04a
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• pp.111-111
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• 2019

Glycyrrhizae radix is one of the most frequently prescribed ingredients in Oriental medicine, and G. radix extract has been shown to exert anti-cancer effects. However, the cellular and molecular mechanisms of apoptosis by G. radix are poorly defined. In the present study, it was examined the biochemical mechanisms of apoptosis by water extract of G. radix (WEGR) in human bladder T24 cancer cells. It was found that WEGR 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, DNA fragmentation and increased populations of annexin-V positive cells. The induction of apoptotic cell death by WEGR was connected with an up-regulation of pro-apoptotic Bax protein expression and down-regulation of anti-apoptotic Bcl-2 and Bcl-xL proteins, and inhibition of apoptosis family proteins (XIAP, cIAP-1 and cIAP-2). In addition, apoptosis-inducing concentrations of WEGR 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. WEGR also induced apoptosis via a death receptor-mediated extrinsic pathway by caspase-8 activation, resulting in the down-regulation of total Bid and suggesting the existence of cross-talk between the extrinsic and intrinsic pathways. Taken together, the present results suggest that WEGR may be a potential chemotherapeutic agent for the control of human bladder cancer cells.

• Journal of Life Science
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• v.28 no.11
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• pp.1268-1276
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• 2018

The cytidine analog decitabine (DEC) acts as a nucleic acid synthesis inhibitor, whereas ammonium pyrrolidine dithiocarbamate (PDTC) is an inhibitor of nuclear factor-${\kappa}B$. The aim of this study was to investigate the possible synergistic inhibitory effect of these two inhibitors on proliferation of human gastric cancer AGS cells. The inhibitory effect of PDTC on AGS cell proliferation was significantly increased by DEC in a concentration-dependent manner, and this inhibition was associated with cell cycle arrest at the G2/M phase and the induction of apoptosis. This induction of apoptosis by the co-treatment with PDTC and DEC was related to the induction of DNA damage, as assessed by H2AX phosphorylation. Further studies demonstrated that co-treatment with PDTC and DEC induced the disruption of mitochondrial membrane potential, increased the generation of intracellular reactive oxygen species (ROS) and the expression of pro-apoptotic Bax, and down-regulated the expression of anti-apoptotic Bcl-2, ultimately resulting in the release of cytochrome c from the mitochondria into the cytoplasm. Co-treatment with PDTC and DEC also activated caspase-8 and caspase-9, which are representative caspases of the extrinsic and intrinsic apoptosis pathways. Co-treatment also activated caspase-3, which was accompanied by proteolytic degradation of poly (ADP-ribose) polymerase. Taken together, these data clearly indicated that co-treatment with PDTC and DEC suppressed the proliferation of AGS cells by increasing DNA damage and activating the ROS-mediated extrinsic and intrinsic apoptosis pathways.

• Journal of Life Science
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• v.29 no.7
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• pp.809-816
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• 2019

The ubiquitous plant metabolite p-coumaric acid (p-CA) has antioxidant and anti-inflammatory properties, but its anti-cancer activity has not been established in gastric cancer cell lines. In this study, we investigated the effects of p-CA on the proliferation and transcriptome profile of SNU16 gastric cancer cells. Treatment with p-CA induced apoptosis of the SNU-16 cells by regulating the expression of pro-apoptotic and anti-apoptotic proteins, such as Bcl-2, poly (ADP-ribose) polymerase (PARP), Bax, procaspase-3, and cleaved-caspase-3. The genes differentially expressed in response to p-CA treatment of the SNU-16 cells were identified by RNA sequencing analysis. Genes regulated by p-CA were involved mainly in the inflammatory response, apoptotic processes, cell cycle, and immune response. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the phosphatidylinositol-3-kinase-Akt and cancer signaling pathways were altered by p-CA. Protein-protein interaction (PPI) network analysis also revealed that p-CA treatment was correlated with differential expression of genes associated with the inflammatory response and cancer. Collectively, these results suggest that p-CA has potential utility in gastric cancer prevention.

• Journal of Life Science
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• v.29 no.9
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• pp.977-985
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• 2019

Aster yomena (Kitam.) Honda is an edible vegetable and perennial herb belonging to the Asteraceae family, and has been used for a long time for the prevention and treatment of various diseases. Although leaf extracts of A. yomena are known to have antioxidant and anti-inflammatory effects, accurate efficacy assessments are still inadequate. In this study, we investigated whether the antioxidant efficacy of ethanol extract of A. yomena leaf (EEAY) is correlated with the anti-inflammatory effect in RAW 264.7 macrophages. The results showed that EEAY significantly inhibited the hydrogen peroxide ($H_2O_2$)-induced growth inhibition in RAW 264.7 cells, which was associated with increased expression of nuclear factor erythroid 2-related factor-2 (Nrf2) and heme oxygenase-1 (HO-1). EEAY pretreatment also effectively prevented $H_2O_2$-induced reactive oxygen species generation and apoptosis through inhibition of caspase-3 activation and poly (ADP-ribose) polymerase degradation. Additionally, EEAY significantly increased the expression and production of interleukin-10, a representative anti-inflammatory cytokine, which was associated with increased expression of toll-like receptor 4 and myeloid differentiation factor 88 at transcriptional and translational levels. Furthermore, the increased production of nitric oxide (NO) by lipopolysaccharide was markedly abolished under the condition of EEAY pretreatment, and the inhibitory effect of NO production by EEAY was further increased by hemin, an HO-1 inducer. Overall, our results suggest that EEAY is able to activate the Nrf2/HO-1 signaling pathway to protect RAW 264.7 macrophages from oxidative and inflammatory stress.

• Journal of Life Science
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• v.29 no.9
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• pp.941-948
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• 2019

Colorectal cancer is a major health problem in industrialized countries. Ziyuglycoside II ($3{\beta}-3-{\alpha}$-1- arabinopyranosyloxy-19-hydroxyurs-12-en-28-oicacid), a triterpenoid saponin isolated from the roots of Sanguisorba officinalis L., possesses antioxidant, antiangiogenic, and anticancer properties. However, the therapeutic function of ziyuglycoside II in colitis-associated colorectal carcinogenesis is undefined. In the present study, the effect of ziyuglycoside II on colitis-associated colon cancer induced in mice using azoxymethane (AOM)/dextran sulfate sodium (DSS) was explored. The AOM model recapitulates many features of human colon cancer, but it lacks an inflammatory component. DSS induces colitis and promotes AOM-induced colon cancer in mice. BALB/c mice were injected with AOM and administered 2% DSS in drinking water. The mice were given ziyuglycoside II (1 or 5 mg/kg) orally three times per week, and colonic tissue was collected at 64 days. Administration of ziyuglycoside II markedly diminished the formation of colonic tumors. Western blot and immunohistological analyses showed that ziyuglycoside II noticeably decreased nuclear factor kappa-B-positive cells and levels of inflammation-related proteins, such as inducible nitric oxide synthase, cyclooxygenase-2, tumor necrosis factor-${\alpha}$, and interleukin-6 in colon tissue. It also prompted apoptosis. Ziyuglycoside II treatment augmented cleaved forms of caspase-3, caspase-7, and poly (ADP-ribose) polymerase in colonic tissues. In conclusion, ziyuglycoside II could defend against colitis-associated tumorigenesis in mice by inhibiting inflammation and inducing apoptosis. This shows a promising chemopreventive potential for its use in colitis-associated colon cancer.

• Journal of Life Science
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• v.29 no.2
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• pp.191-197
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• 2019

Parkinson's disease (PD) is a progressive neurodegenerative disease that mainly affects motor system with clinical features such as bradykinesia, rigidity, tremor and abnormal posture. PD is characterized by the death of dopaminergic neurons in the substantia nigra pars compacta, which is associated with accumulation of oxidative stress and dysregulation of intracellular signaling pathway. Quercetin-3-O-glucuronide (Q3GA), a major metabolite of quercetin, has been reported to have neuroprotective effects. In this study, we examined the neuroprotective effect of Q3GA against 1-methyl-4-phenyl pyridinium ($MPP^+$)-induced neurotoxicity of PD and the underlying molecular mechanisms in SH-SY5Y cells. MTT and LDH assay showed that Q3GA significantly decreased $MPP^+$-induced cell death, which is accompanied by a reduction in poly (ADP-ribose) polymerase (PARP) cleavage. Furthermore, it attenuated $MPP^+$-induced intracellular reactive oxygen species (ROS) with the reduction of Bax/ Bcl-2 ratio. Moreover, Q3GA significantly increased the phosphorylation of Akt and cAMP response element binding protein (CREB), but it has no effects on the phosphorylation of extracellular signal-regulated kinase (ERK). Taken together, these results demonstrate that Q3GA significantly attenuates $MPP^+$-induced neurotoxicity through ROS reduction and Akt/CREB signaling pathway in SH-SY5Y cells. Our findings suggest that Q3GA might be one of the potential candidates for the prevention and/or treatment of PD.