• The Korean Journal of Physiology and Pharmacology
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• v.18 no.6
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• pp.509-516
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• 2014

Radiation therapy for variety of human solid tumors utilizes mechanism of cell death after DNA damage caused by radiation. In response to DNA damage, cytochrome c was released from mitochondria by activation of pro-apoptotic Bcl-2 family proteins, and then elicits massive $Ca^{2+}$ release from the ER that lead to cell death. It was also suggested that irradiation may cause the deregulation of $Ca^{2+}$ homeostasis and trigger programmed cell death and regulate death specific enzymes. Thus, in this study, we investigated how cellular $Ca^{2+}$ metabolism in RKO cells, in comparison to radiation-resistant A549 cells, was altered by gamma (${\gamma}$)-irradiation. In irradiated RKO cells, $Ca^{2+}$ influx via activation of NCX reverse mode was enhanced and a decline of $[Ca^{2+}]_i$ via forward mode was accelerated. The amount of $Ca^{2+}$ released from the ER in RKO cells by the activation of $IP_3$ receptor was also enhanced by irradiation. An increase in $[Ca^{2+}]_i$ via SOCI was enhanced in irradiated RKO cells, while that in A549 cells was depressed. These results suggest that ${\gamma}$-irradiation elicits enhancement of cellular $Ca^{2+}$ metabolism in radiation-sensitive RKO cells yielding programmed cell death.

• Korean Journal of Pharmacognosy
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• v.39 no.4
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• pp.335-340
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• 2008

Diabetes mellitus is metabolic disorder characterized by hyperglycemia caused by insufficient insulin secretion or insulin receptor insensitivity to endogenous insulin. It is well-known that hyperglycemia is one of the main causes of oxidative stress in both type 1 and 2 diabetes. Oxidative stress is related by death of pancreatic ${\beta}$ cell and dysfunction of ${\beta}$ cell. Although ${\beta}$ cell death or dysfunction is induced by many substances or molecules, increased evidences that oxidative stress plays a crucial role in ${\beta}$ cell death or dysfunction. Considering the importance of oxidative stress in the pathogenesis of diabetes mellitus, we investigated the cytoprotective effects against hydrogen peroxide-induced oxidative stress in pancreatic ${\beta}$ cell line RIN-m5F cell. 110 Plant sources were collected in Mt. Baek-du, and extracted with methanol. These extracts had been screened the protective effects against hydrogen peroxide-induced oxidative damage in RIN-m5F cells at 50 and 200 ${\mu}g$/ml. Of these, ten methanolic extracts, aerial part of Erigenron cannadensis, aerial part of Lespedeza juncea, whole plant of Alopecurus aequalis, fruit of Lycium chinense, leaf of Morus alba, rhizome of Polygonatum odoratum, root of Ampelosis japonica, whole plant of Ranunculus japonicus, aerial part of Polygonum sieboldii, rhizome of Arisaema amurense var. violaceum showed significant protective effects against hydrogen peroxide-induced oxidative damage in pancreatic ${\beta}$ cell line RIN-m5F cell.

• Archives of Pharmacal Research
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• v.29 no.11
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• pp.1032-1041
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• 2006

Extracellular adenosine 5'-triphosphate (ATP) affects the function of many tissues and cells. To confirm the biological activity of ATP on human myeloid leukemic cells, F-36P and HL-60, cells were treated with a variety of concentrations of ATP. The stimulation with extracellular ATP induced the arrest of cell proliferation and cell death. from the analysis of Annexin-V staining and caspase activity by flow cytometry. The Annexin-V positive cells in both cell lines were dramatically increased following ATP stimulation. The expression of P2 purinergic receptor genes was confirmed, such as P2X1, P2X4, P2X5, P2X7 and P2Y1, P2Y2, P2Y4, P2Y5, P2Y6, P2Y11 in both leukemic cell lines. Interestingly, ATP induced intracellular calcium flux in HL-60 cells but not in F-36P cells, as determined by Fluo-3 AM staining. Cell cycle analysis revealed that ATP treatment arrested both F-36P and HL-60 cells at G1/G0. Taken together, these data showed that extracellular ATP via P2 receptor genes was involved in the cell proliferation and survival in human myeloid leukemic cells, HL-60 and F-36P cells by the induction of apoptosis and control of cell cycle. Our data suggest that treatment with extracellular nucleotides may be a novel and powerful therapeutic avenue for myeloid leukemic disease.

• Asian Pacific Journal of Cancer Prevention
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• v.14 no.12
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• pp.7069-7074
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• 2013

Programmed cell death is a basic cellular process that is critical to maintaining tissue homeostasis. In contrast to apoptosis, necrosis was previously regarded as an unregulated and uncontrollable process. However, as research has progressed, necrosis, also known as necroptosis or programmed necrosis, is drawing increasing attention, not least becasu of its possible impications for cancer research. Necroptosis exhibits a unique signaling pathway that requires the involvement of receptor interaction protein kinases 1 and 3 (RIP1 and RIP3), mixed lineage kinase domain-like (MLKL), and phosphoglycerate mutase 5 (PGAM5) and can be specifically inhibited by necrostatins. Not only does necroptosis serve as a backup cell death program when apoptosis is inhibited, but it is now recognized to play a pivotal role in regulating various physiological processes and the pathogenesis of a variety of human diseases such as ischemic brain injury, immune system disorders and cancer. The control of necroptosis by various defined trigger factors and signaling pathways now offers the opportunity to target this cellular process for therapeutic purposes. The purpose of this paper is to review current findings concerning the connections between various trigger factors and the RIP1/RIP3 signaling pathway as it relates to necroptosis.

• The Korean Journal of Physiology and Pharmacology
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• v.7 no.6
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• pp.295-301
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• 2003

Striatum plays a crucial role in the movement control and habitual learning. It receives an information from wide area of cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from raphe nuclei. In the present study, the effects of 5-HT to modulate synaptic transmission were studied in the rat corticostriatal brain slice using in vitro extracellular recording technique. Synaptic responses were evoked by stimulation of cortical glutamatergic inputs on the corpus callosum and recorded in the dorsal striatum. 5-HT reversibly inhibited coticostriatal glutamatergic synaptic transmission in a dose-dependent fashion (5, 10, 50, and $10{\mu}M$), maximally reducing in the corticostriatal population spike (PS) amplitude to $40.1{\pm}5.0$% at a concentration of $50{\mu}M$ 5-HT. PSs mediated by non-NMDA glutamate receptors, which were isolated by bath application of the NMDA receptor antagonist, d,l-2-amino-5-phospohonovaleric acid (AP-V), were decreased by application of $50{\mu}M$ 5-HT. However, PSs mediated by NMDA receptors, that were activated by application of zero $Mg^{2+}$ aCSF, were not significantly affected by $50{\mu}M$ 5-HT. To test whether the corticostriatal synaptic inhibitions by 5-HT might involve a change in the probability of neurotransmitter release from presynaptic nerve terminals, we measured the paired-pulse ratio (PPR) evoked by 2 identical pulses (50 ms interpulse interval), and found that PPR was increased ($33.4{\pm}5.2$%) by 5-HT, reflecting decreased neurotransmitter releasing probability. These results suggest that 5-HT may decrease neurotransmitter release probability of glutamatergic corticostriatal synapse and may be able to selectively decrease non-NMDA glutamate receptor-mediated synaptic transmission.

• Biomolecules & Therapeutics
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• v.28 no.2
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• pp.202-210
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• 2020

Fluoxetine is used widely as an antidepressant for the treatment of cancer-related depression, but has been reported to also have anti-cancer activity. In this study, we investigated the cytotoxicity of fluoxetine to human gastric adenocarcinoma cells; as shown by the MTT assay, fluoxetine induced cell death. Subsequently, cells were treated with 10 or 20 µM fluoxetine for 24 h and analyzed. Apoptosis was confirmed by the increased number of early apoptotic cells, shown by Annexin V- propidium iodide staining. Nuclear condensation was visualized by DAPI staining. A significant increase in the expression of cleaved PARP was observed by western blotting. The pan-caspase inhibitor Z-VAD-FMK was used to detect the extent of caspase-dependent cell death. The induction of autophagy was determined by the formation of acidic vesicular organelles (AVOs), which was visualized by acridine orange staining, and the increased expression of autophagy markers, such as LC3B, Beclin 1, and p62/SQSTM 1, observed by western blotting. The expression of upstream proteins, such as p-Akt and p-mTOR, were decreased. Autophagic degradation was evaluated by using bafilomycin, an inhibitor of late-stage autophagy. Bafilomycin did not significantly enhance LC3B expression induced by fluoxetine, which suggested autophagic degradation was impaired. In addition, the co-administration of the autophagy inhibitor 3-methyladenine and fluoxetine significantly increased fluoxetine-induced apoptosis, with decreased p-Akt and markedly increased death receptor 4 and 5 expression. Our results suggested that fluoxetine simultaneously induced both protective autophagy and apoptosis and that the inhibition of autophagy enhanced fluoxetine-induced apoptosis through increased death receptor expression.

• Journal of Acupuncture Research
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• v.32 no.1
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• pp.79-88
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• 2015

Objectives : The purpose of this research was to investigate the cytotoxic effect of Natural Killer(NK)-92 cell and Snake Venom, and to elucidate its mechanism on human lung carcinoma cell A549. Methods : In order to figure out whether Snake Venom enhances the cytotoxic effect of NK-92 cell in A549 cell, Cell Viability Assay was conducted. Also, in order to observe the changes of Caspase-3 and Caspase-8, both of which are proteinases that advance apoptosis, and the changes of TNRF and DR3, which are Death Receptors of the extrinsic pathway of apoptosis, Western Blot Analysis was conducted. By conducting RT-PCR analysis, we have tried to confirm Perforin, Granzyme B, and GADPH, all of which are cytotoxic-related proteins. Lastly, in order to observe the effect of Snake Venom on NO formation within human lung carcinoma cells, NO determination was conducted. Results : 1. After conducting Cell Viability Assay, Snake Venom enhanced the cytotoxic effect of NK-92 cell and inhibited the growth of A549. 2. Western Blot Analysis caused proteinases Caspase-3 and Caspase-8, which advance apoptosis, to increase in the combined treatment group, but not in treatment groups that focused only on either Snake Venom or NK-92 cell in A549 lung carcinoma cells. 3. Western Blot Analysis caused an expression of TNFR2 and DR3, both of which are Death Receptors of the apoptosis extrinsic pathway, in the combined treatment group, but not intreatment groups that focused only on either Snake Venom or NK-92 cell in A549 human lung carcinoma cells. 4. After conducting NO determination, NO formation within A549 cell showed no significant changes in both treatment groups that focused NK-92 cell and combined treatment group. 5. After conducting RT-PCR, the expression of Granzyme B and Perforin, which are cytotoxic-related proteins within A549 human lung carcinoma cells, showed growth in the combined treatment group, but not the treatment group that focused only on NK-92 cell. Conclusion : It has been indicated that, when it comes to the A549 cell, Snake Venom enhances the increase of Death Receptor expression and continuous apoptosis reaction, leading to the enhancement of the cancer cell cytotoxic effect of the NK-92 cell. It is expected that Snake Venom can be used with the NK-92 cell for further lung cancer treatment.

• 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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• Journal of Applied Biological Chemistry
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• v.66
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• pp.138-143
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• 2023

Liver fibrosis is caused by metabolic problems such as cholestasis, genetic problems, or viral infections. Inhibiting hepatic stellate cell (HSC) activation or inducing selective apoptosis of activated HSCs is used as a treatment strategy for liver fibrosis. It has been reported that when HSCs are activated, their apoptosis sensitivity to tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is enhanced because the expression of death receptor 5 is elevated. Finding a natural compound that can enhance the apoptotic effect of TRAIL on HSCs is a necessary strategy for liver fibrosis treatment. It was confirmed here that mangosteen-derived gartanin increased the effect of TRAIL-induced apoptosis by increasing the expression of DR5 in a p38-dependent manner in the hepatic stellate cell line LX-2. Combined treatment with gartanin and TRAIL accelerated DNA cleavage through caspase-3 activation and enhanced antifibrotic effects in LX-2 cells.

• The Korean Journal of Physiology and Pharmacology
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• v.13 no.3
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• pp.175-179
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• 2009

High concentrations of ATP induce membrane blebbing. However, the underlying mechanism involved in epithelial cells remains unclear. In this study, we investigated the role of the P2X7 receptor (P2X7R) in membrane blebbing using Par C5 cells. We stimulated the cells with 5 mM of ATP for 1${\sim}$2 hrs and found the characteristics of membrane blebbing, a hallmark of apoptotic cell death. In addition, 500 ${\mu}M$ Bz-ATP, a specific P2X7R agonist, induced membrane blebbing. However, 300 ${\mu}M$ of Ox-ATP, a P2X7R antagonist, inhibited ATP-induced membrane blebbing, suggesting that ATP-induced membrane blebbing is mediated by P2X7R. We found that ATP-induced membrane blebbing was mediated by ROCK I activation and MLC phosphorylation, but not by caspase-3. Five mM of ATP evoked a biphasic $[Ca^{2+}]_i$ response; a transient $[Ca^{2+}]_i$ peak and sustained $[Ca^{2+}]_i$ increase secondary to ATP-stimulated $Ca^{2+}$ influx. These results suggest that P2X7R plays a role in membrane blebbing of the salivary gland epithelial cells.