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

• Journal of Life Science
• /
• v.26 no.8
• /
• pp.887-894
• /
• 2016

The extract from Artemisia annuain L.(AAE) is known as a medicinal herb that is effective against cancer. Apoptosis is the process of programmed cell death, and mitochondria are known to play a central role in cell death control. In this study, we evaluated the p53-independent apoptosis of extract of AAE through downregulation of Bcl-2 and the mitochondrial pathway in A549 (lung cancer cells). AAE may exert cancer cell apoptosis through regulating p-Akt, Cox-2, p53 and mitochondria-mediated apoptotic proteins. p-Akt/cox-2 is known to play an important role in cell proliferation and cell survival. The Bcl-2 pro-apoptotic proteins (such as Bax, Bak and Bim) mediate the permeabilization of the mitochondrial outer membrane. Treatment of AAE reduces p-Akt, p-Mdm2, cox-2 and anti-apoptotic proteins (such as Bcl-2), while tumor suppressor p53 and pro-apoptotic proteins. Activation of Bax/Bak releases cytochrome c from mitochondria to the cytosol to activate a caspase. Caspase-3 is the major effector caspase associated with apoptotic pathways. Caspase-3 generally exists in cytoplasm in the form of a pro-enzyme. In the initiation stage of apoptosis, caspase-3 is activated by proteolytic cleavage and activated caspase-3 cleaves poly (ADP-ribose) polymerase (PARP). We treated Pifithrin-α (p53 inhibitor) and Celecoxib (Cox-2 inhibitor) to learn the relationship between the signal transduction of proteins associated with apoptosis. These results suggest that AAE induces apoptosis through a p53-independent pathway in A549.

• The Korean Journal of Physiology and Pharmacology
• /
• v.27 no.4
• /
• pp.383-398
• /
• 2023

Dihydroaustrasulfone alcohol (DA), the synthetic precursor of a natural compound (austrasulfone) isolated from the coral species Cladiella australis, has shown cytotoxic effects against cancer cells. However, it is unknown whether DA has antitumor effects on nasopharyngeal carcinoma (NPC). In this study, we determined the antitumor effects of DA and investigated its mechanism of action on human NPC cells. The MTT assay was used to determine the cytotoxic effect of DA. Subsequently, apoptosis and reactive oxygen species (ROS) analyses were performed by using flow cytometry. Apoptotic and PI3K/AKT pathway-related protein expression was determined using Western blotting. We found that DA significantly reduced the viability of NPC-39 cells and determined that apoptosis was involved in DA-induced cell death. The activity of caspase-9, caspase-8, caspase-3, and PARP induced by DA suggested caspase-mediated apoptosis in DA-treated NPC-39 cells. Apoptosis-associated proteins (DR4, DR5, FAS) in extrinsic pathways were also elevated by DA. The enhanced expression of proapoptotic Bax and decreased expression of antiapoptotic BCL-2 suggested that DA mediated mitochondrial apoptosis. DA reduced the expression of pPI3K and p-AKT in NPC-39 cells. DA also reduced apoptosis after introducing an active AKT cDNA, indicating that DA could block the PI3K/AKT pathway from being activated. DA increased intracellular ROS, but N-acetylcysteine (NAC), a ROS scavenger, reduced DA-induced cytotoxicity. NAC also reversed the chances in pPI3K/AKT expression and reduced DA-induced apoptosis. These findings suggest that ROS-mediates DA-induced apoptosis and PI3K/AKT signaling inactivation in human NPC cells.

• Molecules and Cells
• /
• v.39 no.2
• /
• pp.119-128
• /
• 2016

Angelica polymorpha Maxim root extract (APRE) is a popular herbal medicine used for treating stomachache, abdominal pain, stomach ulcers, and rheumatism; however the effect of APRE on cancer cells has not yet been explored. Here, we examined APRE cytotoxicity seen on target neuroblastoma cells (NB) using cell viability assays, DAPI visualization of fragmented DNA, and Western blotting analysis of candidate signaling pathways involved in proliferation and apoptosis. We demonstrated that APRE reduced cell viability in NB to a greater extent than in fibroblast cells. In addition, we found that APRE could inhibit the three classes of MAPK proteins and could also down-regulate the PI3K/AKT/GSK-$3{\beta}$ activity all being relevant for proliferation and survival. APRE could also up-regulate Bax expression and down-regulate Bcl-2 and Mcl-1. With APRE treatment, depolarization of mitochondria membrane potential and activation of caspase-3 was demonstrated in the SH-SY5Y cells. We could not found increased activity of death receptor and caspase-8 as markers of the extrinsic apoptosis pathway for the APRE treated cells. In presence of a caspase-3 siRNA and a pan-caspase inhibitor, APRE could not reduce the viability of NB cells to a significant degree. So we predicted that with APRE, the intrinsic pathway was solely responsible for inducing apoptosis as we also showed that the non-caspase autophagy pathway or ER stress-ROS mediated pathways were not involved. These findings demonstrate that an intrinsic mitochondria-mediated apoptosis pathway mediates the apoptotic effects of APRE on SH-SY5Y cells, and that APRE shows promise as a novel agent for neuroblastoma therapy.

• Biomolecules & Therapeutics
• /
• v.31 no.6
• /
• pp.682-691
• /
• 2023

Cell transformation induced by epidermal growth factor (EGF) and 12-O-tetradecanoylphorbol-13-acetate (TPA) is a critical event in cancer initiation and progression, and understanding the underlying mechanisms is essential for the development of new therapeutic strategies. Licorice extract contains various bioactive compounds, which have been reported to have anticancer and anti-inflammatory effects. This study investigated the cancer preventive efficacy of licochalcone D (LicoD), a chalcone derivative in licorice extract, in EGF and TPA-induced transformed skin keratinocyte cells. LicoD effectively suppressed EGF-induced cell proliferation and anchorage-independent colony growth. EGF and TPA promoted the S phase of cell cycle, while LicoD treatment caused G1 phase arrest and down-regulated cyclin D1 and up-regulated p21 expression associated with the G1 phase. LicoD also induced apoptosis and increased apoptosis-related proteins such as cleaved-caspase-3, cleaved-caspase-7, and Bax (Bcl2-associated X protein). We further investigated the effect of LicoD on the AKT signaling pathway involved in various cellular processes and found decreased p-AKT, p-GSK3β, and p-NFκB expression. Treatment with MK-2206, an AKT pharmacological inhibitor, suppressed EGF-induced cell proliferation and transformed colony growth. In conclusion, this study demonstrated the potential of LicoD as a preventive agent for skin carcinogenesis.

• Journal of Life Science
• /
• v.25 no.11
• /
• pp.1331-1337
• /
• 2015

S-allylcysteine (SAC) is an aged garlic derived water soluble organosulfur compound and has been suggested to have anticarcinogenic activity against diverse types of cancer cells. This review summarizes the cellular signaling pathways and molecular mechanisms whereby SAC exerts its effects on cellular proliferation, apoptosis, cell cycle progression and metastasis based on the results from both in vitro and in vivo studies. SAC activates proapoptotic proteins including Bax and caspase-3, but suppresses antiapoptotic Bcl-2 family proteins to bring about cancer cell death through mitochondria-mediated intrinsic pathway. SAC also inhibits cellular proliferation by inducing cell cycle arrest in which SAC reduces expression and activation of NF-κB, cyclins, Cdks, PCNA and c-Jun, but elevates expression of cell cycle inhibitor proteins p16 and p21 through suppression of both PI3K/Akt/mTOR and MAPK/ERK signaling pathways. And, SAC inhibits invasion and metastasis of cancer cells by inducing suppression of both angiogenesis and epithelial-mesenchymal transition (EMT) through decreased cyclooxygenase (COX)-2 expression and increased E-cadherin expression which were then caused by suppression of inhibitory transcription factors Id-1 and SLUG from SAC-mediated inactivation of both MAPK/ERK and PI3K/Akt/mTOR/NF-κB signaling pathways. Furthermore, SAC prevents toxic compound-induced carcinogenesis by inducing antioxidant enzymes such as glutathione-s-transferase (GST). Thus, SAC can be considered as a potential chemotherapeutic agent for the prevention and treatment of cancer.

• Journal of Life Science
• /
• v.34 no.2
• /
• pp.94-104
• /
• 2024

β-Lapachone is a natural quinone compound originally obtained from the bark of the lapacho tree (Tabebuia vellanedae), which has been used in traditional medicine in several South and Central American countries for treating various diseases. Although β-lapachone has been reported to have potent anticancer activity in many types of cancer cells, its effect on the proliferation of hepatocellular carcinoma (HCC) cells is still unclear. Therefore, in this study, we investigated the effect of β-lapachone on the proliferation of human HCC Hep3B cells. According to our results, the decrease in cell viability of Hep3B cells caused by β-lapachone was closely related to the induction of apoptosis, which was confirmed through changes in nuclear morphology and flow cytometry. In addition, in Hep3B cells treated with β-lapachone, the expression of Bcl-2, an anti-apoptotic factor, was decreased, while the expression of Bax, an apoptosis inducer, was increased, and the activity of the caspase cascade was also increased. However, in the presence of a pan-caspase inhibitor, β-lapachone-induced apoptosis was weakened, indicating that the induction of apoptosis by β-lapachone was caspase-dependent. Moreover, β-lapachone treatment activated extracellular-regulated kinase (ERK) signaling while inhibiting activation of the phosphoinositide 3 kinase (PI3K)/Akt pathway. Furthermore, the effect of the ERK inhibitor on suppressing the induction of apoptosis by β-lapachone was minimal, and the PI3K inhibitor significantly increased β-lapachone-induced apoptosis. The findings from this study will contribute to a better understanding of the anticancer activity of β-lapachone in HCC cells.

• Journal of Life Science
• /
• v.31 no.3
• /
• pp.321-329
• /
• 2021

This study examined the growth inhibitory effect of the methanol fraction of maesil (Prunus mume) extract (MMF) on LNCaP, PC-3, and RC-58T human prostate cancer cell lines. Among these cell lines, LNCaP was the most sensitive to the inhibitory effects of MMF. Observation of the morphology and apoptotic body formation in the LNCaP cells revealed morphological changes, nuclear damage, and condensation in response to MMF treatment. The suppressive effect of MMF was related to the intrinsic apoptosis pathway, as indicated by increased expression of the pro-apoptotic proteins Bax, capase-3, capase-9, and PARP and decreased expression of the anti-apoptotic protein Bcl-2. Combined treatment with MMF and the AIF inhibitor N-phenylmalemide (N-PM) indicated that MMF treatment alone had a significant growth suppression effect. The involvement of the extrinsic apoptosis pathway was also confirmed by increased expression of AIF and Endo G. The growth suppression effect of MMF was also significant when compared to the effects of a combination of the PI3K inhibitor LY294002 and MMF. The reduced expression of PI3K, p-Akt, and p-mTOR confirmed the involvement of the PI3K/Akt/ mTOR signaling pathway in regulating the anti-proliferative properties of MMF. In conclusion, the growth suppression effect of MMF in the LNCaP human prostate cancer cell line shows the possibility of using this natural product in functional foods.

• Molecules and Cells
• /
• v.41 no.3
• /
• pp.234-243
• /
• 2018

In recent years, the interest towards the relationship between incretins and bone has been increasing. Previous studies have suggested that glucagon-like peptide-1 (GLP-1) and its receptor agonists exert beneficial anabolic influence on skeletal metabolism, such as promoting proliferation and differentiation of osteoblasts via entero-osseous-axis. However, little is known regarding the effects of GLP-1 on osteoblast apoptosis and the underlying mechanisms involved. Thus, in the present study, we investigated the effects of liraglutide, a glucagon-like peptide-1 receptor agonist, on apoptosis of murine MC3T3-E1 osteoblastic cells. We confirmed the presence of GLP-1 receptor (GLP-1R) in MC3T3-E1 cells. Our data demonstrated that liraglutide inhibited the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation, as detected by Annexin V/PI and Hoechst 33258 staining and ELISA assays. Moreover, liraglutide upregulated Bcl-2 expression and downregulated Bax expression and caspase-3 activity at intermediate concentration (100 nM) for maximum effect. Further study suggested that liraglutide stimulated the phosphorylation of AKT and enhanced cAMP level, along with decreased phosphorylation of $GSK3{\beta}$, increased ${\beta}-catenin$ phosphorylation at Ser675 site and upregulated nuclear ${\beta}-catenin$ content and transcriptional activity. Pretreatment of cells with the PI3K inhibitor LY294002, PKA inhibitor H89, and siRNAs GLP-1R, ${\beta}-catenin$ abrogated the liraglutide-induced activation of cAMP, AKT, ${\beta}-catenin$, respectively. In conclusion, these findings illustrate that activation of GLP-1 receptor by liraglutide inhibits the apoptosis of osteoblastic MC3T3-E1 cells induced by serum deprivation through $cAMP/PKA/{\beta}-catenin$ and $PI3K/Akt/GSK3{\beta}$ signaling pathways.

• The Korean Journal of Physiology and Pharmacology
• /
• v.26 no.6
• /
• pp.447-456
• /
• 2022

The present study was carried out to investigate the effect of Arctigenin on cell growth and the mechanism of cell death elicited by Arctigenin were examined in FaDu human pharyngeal carcinoma cells. To determine the apoptotic activity of Arctigenin in FaDu human pharyngeal carcinoma cells, cell viability assay, DAPI staining, caspase activation analysis, and immunoblotting were performed. Arctigenin inhibited the growth of cells in a dose-dependent manner and induced nuclear condensation and fragmentation. Arctigenin-treated cells showed caspase-3/7 activation and increased apoptosis versus control cells. FasL, a death ligand associated with extrinsic apoptotic signaling pathways, was up-regulated by Arctigenin treatment. Moreover, caspase-8, a part of the extrinsic apoptotic pathway, was activated by Arctigenin treatments. Expressions of anti-apoptotic factors such as Bcl-2 and Bcl-xL, components of the mitochondria-dependent intrinsic apoptosis pathway, significantly decreased following Arctigenin treatment. The expressions of pro-apoptotic factors such as BAX, BAD and caspase-9, and tumor suppressor -53 increased by Arctigenin treatments. In addition, Arctigenin activated caspase-3 and poly (ADP-ribose) polymerase (PARP) induced cell death. Arctigenin also inhibited the proliferation of FaDu cells by the suppression of p38, NF-κB, and Akt signaling pathways. These results suggest that Arctigenin may inhibit cell proliferation and induce apoptotic cell death in FaDu human pharyngeal carcinoma cells through both the mitochondria-mediated intrinsic pathway and the death receptor-mediated extrinsic pathway.