• Journal of the Korean Society of Food Science and Nutrition
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• v.38 no.4
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• pp.442-450
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• 2009

Piperine is an alkaloid-amine found in pepper and has been reported to have anticarcinogenic properties. To explore the possibility that piperine has cancer chemopreventive and chemotherapeutic effects in colon cancer, we examined whether piperine inhibits the growth of HT-29 human colon cancer cells and investigated the mechanisms for this effect. Cells were cultured with various concentrations ($0{\sim}40{\mu}M$) of piperine. Piperine decreased the cell viability and induced apoptosis of HT-29 cells. Western blot analysis of total cell lysates revealed that piperine decreases the protein levels of Bcl-2, Mcl-1, and intact Bid but increases Bik levels. Piperine increased the percentage of cells with depolarized mitochondrial membrane, and the release of cytochrome c into cytoplasm. Piperine induced the cleavage of poly (ADP-ribose) polymerase and caspases 8, 9, 7, and 3 and increased the Fas levels. In addition, piperine significantly decreased the protein levels of survivin. The present results indicate that piperine inhibits the growth of HT-29 colon cancer cells by the induction of apoptosis, which may be mediated by its ability to change the Bcl-2 family proteins, increase the activation of caspases, and decrease survivin levels. Overall, our findings suggest that piperine has cancer chemotherapeutic effects in colon cancer.

• 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.

• Journal of Life Science
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• v.20 no.9
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• pp.1324-1331
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• 2010

Mifepristone (MIF) and Tamoxifen (TAM) have been used in the treatment of prostate cancer and breast cancer for more than a decade. MIF can induce apoptosis in both AR-positive and negative prostate cancer cells. Because of its pleiotropic ligand-receptor properties, TAM exerts cytotoxic activity in estrogen (ER)-positive and various ER.negative cancer cells. However, the molecular mechanisms of these two substances are not yet clear. In the present work, we report that the cytotoxic effects of MIF and TAM are due to the modulation of intracellular $Ca^{2+}$ level in DU-145, androgen-insensitive cells. When the cells were treated with micromolar concentrations of either MIF or TAM, the growth and viability were significantly decreased in a dose- and time-dependent manner. The apoptosis induced by MIF or TAM was further proved and analyzed by confocal laser scanning microscopy (CLSM) and fluorescence-activated cell sorting (FACS). In the cells cultivated in a normal 1.5 mM $Ca^{2+}$ medium, both MIF and TAM also induced an increase of the intracellular $Ca^{2+}$ level in a dose-dependent fashion. Since a change in calcium level could not be found in cells of the $Ca^{2+}$-free medium, the increase of intracellular $Ca^{2+}$ level might be due to an increase in extracellular calcium uptake. Our results show that the apoptotic effect was more prominent in TAM treatment compared to MIF treatment in DU-145 cells. The above findings might be due to the difference in the uppermost pathways of apoptosis induced by either MIF or TAM. When we checked the level of procaspase-8 activation, TAM showed minor level of activation, as opposed to MIF, which exerted strong activation. In both treatments, the levels of anti-apoptotic protein Bcl-2 decreased, and pro-apoptotic protein Bax level increased more than 2-fold. The activation of caspase-3, a key protease enzyme in the downstream pathway of apoptosis, was much higher in the cells treated with TAM, compared to the MIF treatment. The overall apoptotic activity shown in the present work was closely related to intracellular $Ca^{2+}$ concentration levels. Therefore, the cytotoxic activity induced by MIF and TAM might have been due to intracellular calcium modulation.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.338-346
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• 2015

This study was performed to elucidate the anti-proliferative and apoptotic mechanism of flavonoids in HT-29 human colon cancer cells. We investigated the anti-proliferative activity of flavonoids in HT-29 human colon cancer cells via cell viability assay (MTT assay), caspase-3 activity, RT-PCR, and western blotting. We cultured HT-29 cells in the presence of various flavonoids (apigenin, rutin, naringenin, and myricetin) at a concentration of $100{\mu}M$. In the MTT assay, naringenin showed the strongest effect on cell viability in HT-29 colon cancer cells. Caspase-3 activity, a marker of apoptosis, significantly increased upon naringenin treatment. For RT-PCR, myricetin significantly increased Bax protein levels, naringenin increased p53 protein levels, and rutin reduced expression of the anti-apoptotic protein Bcl-2. Western blotting of HT-29 colon cancer cells showed that myricetin increased cleaved caspase-3 protein levels, naringenin significantly increased poly (ADP-ribose) polymerase protein levels, and rutin increased E-cadherin protein levels. These results indicate that flavonoid exerts anticancer effects on human colon HT-29 cells through a caspase-dependent apoptotic pathway.

• Journal of Life Science
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• v.29 no.12
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• pp.1393-1400
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• 2019

In the present study, we examined the effect of mitochondrial K⁺ channel opener diazoxide on the mitochondria-dependent apoptotic signaling in endothelial cells exposed to high glucose (HG) media. Endothelial cells derived from human umbilical veins were exposed to HG media containing 30 mM glucose, and the degree of apoptotic cell death associated with activation of the mitochondria-dependent apoptotic signaling pathway was determined. Exposure to HG media was seen to enhance apoptotic cell death in a time-dependent manner. In these cells, activation of caspases 3, 8, and 9 was observed, and while caspase-3 and -9 inhibitors suppressed the HG-induced apoptotic cell death, a caspase-8 inhibitor did not. The HG-treated cells exhibited disruption of mitochondrial membrane potential, formation of permeability transition pores, and cytosolic release of cytochrome c. Subsequently, diazoxide was seen to attenuate the HG-induced apoptotic cell death; caspase-9 activation was suppressed but caspase 8 was not. Diazoxide also suppressed the depolarization of mitochondrial membrane potential, the formation of mitochondrial permeability transition pores, and the release of cytochrome c. These effects were significantly inhibited by 5-hydroxydecanoate, a selective blocker of ATP-sensitive K⁺ channels (K_ATP). The present results demonstrate that diazoxide exhibits a beneficial effect to ameliorate HG-induced endothelial cell apoptosis. Opening the K_ATP could help preserve the functional integrity of mitochondria and provide an underlying mechanism to suppress HG-triggered apoptotic signaling.

• Korean Journal of Environmental Agriculture
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• v.28 no.3
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• pp.295-300
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• 2009

Formaldehyde (FA) is an important irritant compound in pesticide to induce asthma and allergy in respiratory system. Alveolar macrophage is also an pivotal cell in the immune response of respiratory system. However, the effect of FA in macrophage cell viability has not been elucidated. Thus, this study was conducted to investigate the effect of FA on apoptosis in Raw 264.7 cells, alveolar macrophage cell line. In this study, FA decreased cell viability of lung alveolar macrophage cells in a dose-dependent manner (>$100{\mu}M$). FA-induced decrease of cell viability was blocked by the treatment of antioxidants (vitamin C, NAC, and catalase). Indeed, FA induced lipid peroxide formation in Raw 264.7 cells. FA decreased Bcl-2 expression but increased Bax expression in lung alveloar macrophage cells. In addition, FA also increased the cleaved form of caspase-3. In conclusion, FA induced apoptosis via oxidative stress in cultured Raw 264.7 cells.

• Journal of Life Science
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• v.21 no.2
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• pp.316-321
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• 2011

Generation of tryptophan-derived metabolites by indoleamine 2,3-dioxygenase (IDO) is a potent immunoregulatory mechanism in T cell responses. However, the mechanism remains unclear. We showed that 3-hydroxyanthranilic acid (3-HAA), the most potent metabolite, selectively induced apoptosis in activated T cells, but not in resting T cells. This was not associated with cell cycle arrest. We found that TRAIL expression was selectively induced in activated T cells by treatment of 3-HAA. Blockade of the TRAIL: DR4/DR5 pathway significantly inhibited 3-HAA-mediated T cell death. Our data suggest that TRAIL-induced apoptosis is involved in the mechanism of 3-HAA-mediated T cell death.

• Development and Reproduction
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• v.16 no.2
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• pp.129-135
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• 2012

Previously, we identified that the overexpression of IEX-1 induces apoptosis in ovarian cancer cells. Herein we report a new binding partner of IEX-1, CATHEPSIN B, as a lysosomal enzyme which contributes to the various apoptotic signaling in tumor cells. To investigate how IEX-1 regulates cellular survival and death event, we performed yeast two-hybrid screening of rat ovarian cDNA library using IEX-1 as the bait and found CATHEPSIN B. In the present study, CATHEPSIN B and IEX-1 proteins were overexpressed in 293T cells and their specific association was determined by immunoprecipitation and immunoblot analysis. In addition, the endogenous interaction between CATHEPSIN B and IEX-1 was confirmed in HeLa cells. The current finding of lysosomal CATHEPSIN B as the IEX-1-binding partner implies that IEX-1 may involve in lysosome-mediated apoptotic signaling pathways.

• Journal of Applied Biological Chemistry
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• v.66
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• pp.7-14
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• 2023

The effects of fermented Achyranthes japonica Nakai, Angelica gigas Nakai, and Eucommia ulmoides Oliver extracts (FAAE) on regulation of inflammation and apoptosis were investigated in primary cultured rat cartilage cells. To identify the protective effects of FAAE against H₂O₂, cell survival was measured by MTT assay. Smad3, Collagen type I, MMP3, and MMP13 were measured by real-timpe PCR and westernbot and the inflammatory (NF-κB pathway, COX-2, iNOS) factors were determined by western blot. The apoptosis related factors (JNK, c-Fos, c-Jun, caspase 3, Bax, and Bcl-2) were determined by western blot. FAAE significantly increased the follwing: H₂O₂ treated cell survival, mRNA and protein expression of Smad 3, collagen type I. In addition, FAAE significantly decreased the protein expression of inflammatory and apoptosis related factors. This study suggests that FAAE have a protection effect of chondrocytes through inhibition of inflammation and apoptosis. Thus, FAAE is a therapeutic potential food componet in osteoarthritis.

• Journal of Life Science
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• v.22 no.11
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• pp.1500-1506
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• 2012

Transforming growth factor (TGF)-${\beta}$-dependent apoptosis is important in the elimination of damaged or abnormal cells from normal tissues, especially in liver, in vivo. To investigate which gene expressions are critical for TGF-${\beta}$-induced apoptosis in hepatocytes, gene expression profiling experiments were performed with TGF-${\beta}$-treated and non-treated mouse hepatocytes AML12 cells. Findings showed that serum and glucocorticoid-inducible protein kinase1 (SGK1) expression is markedly downregulated during TGF-${\beta}$-induced apoptosis. Findings confirmed that expression of SGK1 protein, as well as mRNA, is also markedly decreased with TGF-${\beta}$ treatment. Infection of adenoviral vector encoding constitutively active SGK1 (CA-SGK1), but not kinase dead SGK1 (KD-SGK1), attenuated TGF-${\beta}$-induced apoptosis. All of these results suggest that downregulation of SGK1 expression is critical for TGF-${\beta}$-induced apoptosis in AML12 cells.