• Korean Journal of Microbiology
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• v.39 no.4
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• pp.216-222
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• 2003

Human caspase-9, an essential apoptosis initiator protease, was excessively degraded when expressed in Escherichia coli under the conventional induction condition. To optimize the conditions for induction and develop a rapid purification method for obtaining significant amounts of wild-type procaspase-9, we expressed procaspase-9 as GST fusion in E. coli. The addition of 0.01 mM IPTG as an inducer to the bacterial culture and decreasing the culture temperature to 25oC improved the production of procasapse-9 protein by circumventing proteolytic degradation in E. coli. The wild-type procaspae-9 was purified to approximately 70% purity with relatively high yields using the method developed in this study. In addition, we found that GST-caspase-9 is autocatalytically cleaved after aspartic acid 315, which is the same site for processing in mammalian cells, during expression in E. coli.

• Journal of Radiation Protection and Research
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• v.32 no.4
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• pp.134-139
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• 2007

In order to find out the Radioprotective effect of algin-oligosaccharide(AOS), this study, with a mouse of which whole frame irradiated by 3 Gy radiation once, measured caspase-3 and caspase-9 amid cell signaling connected to apoptosis in order to observe cell activation. In Caspase-3 and Caspase-9 test for observing cell activation, both of Caspase-3 and Caspase-9 showed highly increased O.D. value in the irradiation control group, while the whole groups treated with algin-oligosaccharide before or after irradiation indicated lower O.D. value than the irradiation control group, especially showed big difference in 7 day's treatment group of before irradiation (P<0.001). It confirmed that Caspase generation was restrained in AOS treatment group. Consequently, this study inquired into the fact that algin-oligosaccharide with superior antioxidant activity performed radiation protection by inducing restraint of Caspase generation and confirmed that natural product with less chemical toxicity was able to be applied as radioprotector.

• Journal of Life Science
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• v.27 no.2
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• pp.164-171
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• 2017

Our previous study suggested that S-allylcysteine (SAC) inhibits the proliferation of the human cervical cancer cell line, HeLa, at least in part through the induction of apoptosis and cell cycle arrest. To further analyze the specific molecular mechanism(s) by which SAC mediates its antiproliferative effects, this study examined the role of SAC in regulating the protein expression of initiator caspase (caspase-9), effector caspases (caspase-3 and caspase-7), and poly-ADP-ribose polymerase (PARP) in HeLa. Western blot analysis showed that when cells were treated with 50 mM SAC for 48 hr, the expression of procaspase-3, -7, and -9 and PARP was reduced by 94%, 38%, 95%, and 64%, respectively, as compared to the untreated control. In contrast, the expression of caspase-3, -7, and -9 and cleaved-PARP was markedly increased by SAC treatment. The SAC-mediated changes in the expression of these proteins were correlated with the concomitant inhibition of cellular proliferation by SAC. The cell proliferation assay showed that HeLa treatment with more than 20 mM SAC for 6-48 hr resulted in both concentration- and time-dependent inhibition of cellular proliferation. These results indicate that the SAC-induced antiproliferative effect in HeLa may be mediated at least in part through the activation of caspase-9, followed by the activation of caspase-3 and caspase-7 as well as the inactivation of PARP, thus leading to cellular apoptosis.

• BMB Reports
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• v.50 no.10
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• pp.510-515
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• 2017

Triglyceride (TG) accumulation causes macrophage cell death, which affects the development of atherosclerosis. Here, we examined whether caspase-2 is implicated in TG-induced macrophage cell death. We found that caspase-2 activity is increased in TG-treated THP-1 macrophages, and that inhibition of caspase-2 activity drastically inhibits TG-induced cell death. We previously reported that TG-induced macrophage cell death is triggered by caspase-1, and thus investigated the relationship between caspase-2 and caspase-1 in TG-induced macrophage cell death. Inhibition of caspase-2 activity decreased caspase-1 activity in TG-treated macrophages. However, caspase-1 inhibition did not affect caspase-2 activity, suggesting that caspase-2 is upstream of caspase-1. Furthermore, we found that TG induces activation of caspase-3, -7, -8, and -9, as well as cleavage of PARP. Inhibition of caspase-2 and -1 decreased TG-induced caspase-3, -7, -8, and -9 activation and PARP cleavage. Taken together, these results suggest that TG-induced macrophage cell death is mediated via the caspase-2/caspase-1/apoptotic caspases/PARP pathways.

• Toxicological Research
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• v.17 no.3
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• pp.215-223
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• 2001

Cadmium is an ubiquitous toxic metal and chronic exposure to cadmium results in the accumulation of cadmium in the liver and kidneys. In contrast, acute exposure leads to damage mainly in the liver. Apoptosis induced by cadmium has been shown in many tissues in vivo and in cultured cells in vitro. However, the molecular mechanism of cadmium-induced apoptosis is not clear in hepatocyte. To investigate the induction of apoptosis in the hepatocyte, we used mouse hepatoma cell line, Hepalclc7 cells, and analysed the molecules that involved in cadmium-induced apoptosis. Cadmium induced the genomic DNA fragmentation, PARP cleavage, and activation of caspase-3 like protease. Caspase-9 cysteine protease was activated in a time-dependent manner but caspase-8 cysteine protease was not significantly activated in cadmium-treated Hepalclc7 cells. Cadmium also induced mitochondrial dysfunction including cytochrome c release from mitochondria, change oj mitochondrial membrane potential tranition, and tranlocation of Bax Protein into mitochondria. These results strong1y indicated that the signal Pathway of apoptotic death in cadmium-treated Hepalclc7 cells is modulated by caspase cascade via mitochondria.

• Biomedical Science Letters
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• v.25 no.1
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• pp.66-74
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• 2019

Hyperlipidemia is defined as conditions of the accumulation of lipids such as free fatty acids (FFA), triglyceride (TG), cholesterol and/or phospholipid in the bloodstream. Hyperlipidemia can cause lipid accumulation in non-adipose tissue, which is lipid-cytotoxic effects in many tissues and mediates cell dysfunction, inflammation or programmed cell death (PCD). TG is considered to be a major cause of atherosclerosis through inflammatory necrosis of vascular endothelial cells. Recently, TG have also been shown to exhibit lipid-cytotoxicity and induce PCD. Therefore, we investigated the effect of TG on the cytotoxic effect of various cell types. When exposed to TG, the cell viability of U937 monocytes and Jurkat T lymphocytes, as well as the cell viability of MCF-7, a non-immune cell, decreased in time- and dose-dependent manner. In U937 cells and Jurkat cells, caspase-9, an intrinsic apoptotic caspase, and caspase-8, an extrinsic apoptotic caspase, were increased by exposure to TG. However, in TG-treated MCF-7 cells, caspase-8 activity increased only without caspase-9 activity. In addition, the reduction of cell viability by TG was recovered when all three cell lines were treated with pan-caspase inhibitor. These results suggest that activation of apoptotic caspases by TG causes lipotoxic effect and decreases cell viability.

• Food Science and Biotechnology
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• v.17 no.6
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• pp.1305-1309
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• 2008

Baicalein, one of the major flavonoid in Scutellaria baicalensis, has been known for its effects on proliferation and apoptosis of many tumor cell lines. Most biological effects of baicalein are thought to be from its antioxidant and prooxidant activities. In this report, baicalein was found to induce apoptosis in HL60 human promyelocytic leukemia cell line. Baicalein treatment induced DNA fragmentation and typical morphological features of apoptosis. To elucidate the mechanism of baicalein-induced apoptosis, the activities of the members of caspase family were measured. Interestingly caspase 2, 3, and 6 were significantly activated whereas caspase 1, 8, and 9 were not activated, suggesting selective involvement of specific caspases. Further, treatment with caspase inhibitors also supports the involvement of caspase 2 in apoptosis process. Although it has been reported that baicalein can induce apoptosis through many caspase pathways, the present study indicates that caspase 2 not caspase 9 pathway may be the important step in apoptosis on HL60 cell line.

• BMB Reports
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• v.37 no.4
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• pp.445-453
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• 2004

We identified apoptosis as being a significant mechanism of toxicity following the exposure of HeLa cell cultures to abrin holotoxin, which is in addition to its inhibition of protein biosynthesis by N-glycosidase activity. The treatment of HeLa cell cultures with abrin resulted in apoptotic cell death, as characterized by morphological and biochemical changes, i.e., cell shrinkage, internucleosomal DNA fragmentation, the occurrence of hypodiploid DNA, chromatin condensation, nuclear breakdown, DNA single strand breaks by TUNEL assay, and phosphatidylserine (PS) externalization. This apoptotic cell death was accompanied by caspase-9 and caspase-3 activation, as indicated by the cleavage of caspase substrates, which was preceded by mitochondrial cytochrome c release. The broad-spectrum caspase inhibitor, benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone (zVAD-fmk), prevented abrin-triggered caspase activation and partially abolished apoptotic cell death, but did not affect mitochondrial cytochrome c release. These results suggest that the release of mitochondrial cytochrome c, and the sequential caspase-9 and caspase-3 activations are important events in the signal transduction pathway of abrin-induced apoptotic cell death in the HeLa cell line.

• BMB Reports
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• v.46 no.9
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• pp.471-476
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• 2013

The PIDDosome, which is an oligomeric signaling complex composed of PIDD, RAIDD and caspase-2, can induce proximity-based dimerization and activation of caspase-2. In the PIDDosome assembly, the adaptor protein RAIDD interacts with PIDD and caspase-2 via CARD:CARD and DD:DD, respectively. To analyze the PIDDosome assembly, we purified all of the DD superfamily members and performed biochemical analyses. The results revealed that caspase-2 CARD is an insoluble protein that can be solubilized by its binding partner, RAIDD CARD, but not by full-length RAIDD; this indicates that full-length RAIDD in closed states cannot interact with caspase-2 CARD. Moreover, we found that caspase-2 CARD can be solubilized and interact with full-length RAIDD in the presence of PIDD DD, indicating that PIDD DD initially binds to RAIDD, after which caspase-2 can be recruited to RAIDD via a CARD:CARD interaction. Our study will be useful in determining the order of assembly of the PIDDosome.

• The Journal of Korean Medicine
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• v.29 no.4
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• pp.171-179
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• 2008

Objective: Bufonis Venenum is the traditional Korean medicine Chan Su, which is obtained from the skin and parotid venom gland of the toads. It has been used for myocardial diseases, inflammation diseases, pain relief, cancer and others. The main components of BV are cinobufotoxin, cinobufalin, bufalin and others. Of these, bufalin, the major active ingredient of BV, has been reported to induce apoptosis and to possess anti-tumor effects. There was no report of anti-tumor screening of BV on hepatic cancer and which signaling pathway can be involved. In order to examine the effect of BV on hepatic cancer and the related signaling pathway with BV-induced apoptosis, human Hep G2 cells were used. Methods: Analysis of apoptosis was confirmed by MTT assay. BV decreased cell viability in a dose and duration dependent manner. To observe which signaling molecules will be activated by BV, phosphorylation of MAPK (p38, ERK, JNK), caspase 8 and caspase 9 were examined by Western blot analysis. Results: The phosphorylation levels of p38 started to increase at 5 min after addition of 5 ${\mu}g$/ml of BV and sustained to increase until 48 hours. The phosphorylation levels of other MAPK (ERK and JNK), caspase 8 and caspase 9 increased in a time-dependent manner. These imply that BV may activate different signaling pathways, MAPK, caspase 8 and caspase 9. These results propose that BV may induce apoptosis on Hep G2 cells through the activation of MAPK, caspase 8 and caspase 9.