• Journal of Life Science
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• v.19 no.11
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• pp.1529-1537
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• 2009

To elucidate further the antitumor effects of a natural L-arginine analogue, L-canavanine, the mechanism underlying apoptogenic activity of L-canavanine and its modulation by protein tyrosine kinase $p56^{lck}$ was investigated in human Jurkat T cells. When the cells were treated with 1.25 to 2.5 mM L-canavanine for 36 h, several apoptotic events including mitochondrial membrane potential (${\Delta\Psi}m$) loss, activation of caspase-9, -3, -8, and -7, poly (ADP-ribose) polymerase (PARP) degradation, and DNA fragmentation were induced without alteration in the levels of Fas or FasL. These apoptotic changes were more significant in $p56^{lck}$-deficient Jurkat clone JCaM1.6 than in $p56^{lck}$-positive Jurkat clone E6.1. The L-canavanine-induced apoptosis observed in $p56^{lck}$-deficient JCaM1.6 cells was significantly reduced by introducing $p56^{lck}$ gene into JCaM1.6 cells by stable transfection. Treatment of JCaM1.6/lck cells with L-canavanine caused a transient 1.6-fold increase in the kinase activity of $p56^{lck}$. Both FADD-positive wild-type Jurkat T cell clone A3 and FADD-deficient Jurkat T cell clone I2.1 exhibited a similar susceptibility to the cytotoxicity of L-canavanine, excluding involvement of Fas/FasL system in triggering L-canavanine-induced apoptosis. The L-canavanine-induced apoptotic sub-$G_1$ peak and activation of caspase-3, -8, and -7 were abrogated by pan-caspase inhibitor (z-VAD-fmk), whereas L-canavanine-induced activation of caspase-9 was not affected. These results demonstrated that L-canavanine caused apoptosis of Jurkat T cells via the loss of ${\Delta\Psi}m$, and the activation of caspase-9, -3, -8, and -7, leading to PARP degradation, and that the $p56^{lck}$ kinase attenuated the ${\Delta\Psi}m$ loss and activation of caspases, and thus contributed as a negative regulator to L-canavanine-induced apoptosis.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.7
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• pp.3289-3294
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• 2016

Naringin, a bioflavonoid found in Citrus seeds, inhibits proliferation of cancer cells. The objectives of this study were to investigate the mode and mechanism(s) of hepatocellular carcinoma HepG2 cell death induced by naringin. The cytotoxicity of naringin towards HepG2 cells proved dose-dependent, measured by MTT assay. Naringin-treated HepG2 cells underwent apoptosis also in a concentration related manner, determined by annexin V-fluorescein isothiocyanate (FITC) and propidium iodide (PI) employing flow cytometry. Mitochondrial transmembrane potential (MTP) measured using 3,3'-dihexyloxacarbocyanine iodide ($DiOC_6$) and flow cytometer was reduced concentration-dependently, which indicated influence on the mitochondrial signaling pathway. Caspase-3, -8 and -9 activities were enhanced as evidenced by colorimetric detection of para-nitroaniline tagged with a substrate for each caspase. Thus, the extrinsic and intrinsic pathways were linked in human naringin-treated HepG2 cell apoptosis. The expression levels of pro-apoptotic Bax and Bak proteins were increased whereas that of the anti-apoptotic Bcl-xL protein was decreased, confirming the involvement of the mitochondrial pathway by immunoblotting. There was an increased expression of truncated Bid (tBid), which indicated caspase-8 proteolysis activity in Bid cleavage as its substrate in the extrinsic pathway. In conclusion, naringin induces human hepatocellular carcinoma HepG2 cell apoptosis via mitochondria-mediated activation of caspase-9 and caspase-8-mediated proteolysis of Bid. Naringin anticancer activity warrants further investigation for application in medical treatment.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.13
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• pp.5463-5468
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• 2014

MicroRNAs might act as oncogenes or tumor suppressors in cancer. Recent studies have shown that miR-421 is up-regulated in human gastric cancer. Here, we found that miR-421 was over-expressed in gastric cancer tissues and cell lines. Bioinformatics analysis predicted that the caspase-3 gene was a target of miR-421. Caspase-3 was negatively regulated by miR-421 at the post-transcriptional level. Bax and Bcl-2 were also regulated by miR-421. Moreover, tumor necrosis factor receptor-I and -II, death receptors in the apoptosis pathway, were up-regulated by miR-421. The over-expression of miR-421 promoted gastric cancer cell growth and inhibited apoptosis of the BGC-823 gastric cancer cell line. These observations indicate that miR-421 acts as a tumor promoter by targeting the caspase-3 gene and preventing apoptosis of gastric cancer cells through inhibition of caspase-3 expression. These findings contribute to our understanding of the functions of miR-421 in gastric cancer.

• BMB Reports
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• v.46 no.12
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• pp.588-593
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• 2013

Apoptosis, programmed cell death, is a process involved in the development and maintenance of cell homeostasis in multicellular organisms. It is typically accompanied by the activation of a class of cysteine proteases called caspases. Apoptotic caspases are classified into the initiator caspases and the executioner caspases, according to the stage of their action in apoptotic processes. Although caspase-3, a typical executioner caspase, has been studied for its mechanism and substrates, little is known of caspase-6, one of the executioner caspases. To understand the biological functions of caspase-6, we performed proteomics analyses, to seek for novel caspase-6 substrates, using recombinant caspase-6 and HepG2 extract. Consequently, 34 different candidate proteins were identified, through 2-dimensional electrophoresis/MALDI-TOF analyses. Of these identified proteins, 8 proteins were validated with in vitro and in vivo cleavage assay. Herein, we report that HAUSP, Kinesin5B, GEP100, SDCCAG3 and PARD3 are novel substrates for caspase-6 during apoptosis.

• Journal of Life Science
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• v.21 no.6
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• pp.851-857
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• 2011

Sulforaphane (SFN) is an isothiocyanate, isolated from glucoraphanin in broccoli and other cruciferaous vegetables. Recent studies have revealed that SFN induces anti-proliferation and apoptosis by cell cycle arrest in various cancer cells. In this study, we investigated the effect of SFN induced apoptosis in chondrosarcoma HTB-94 cells. SFN caused suppression of proliferation and apoptosis in a dose-dependent manner as determined by cell phenotype, MTT assay and FACS analysis in HTB-94 cells. Treatment of SFN led to caspase-3 activation and p53 accumulation as determined by Western blot analysis. Also, SFN significantly induced DNA fragmentation and nuclear degradation though activation of caspase-3, as detected by DNA electrophoresis and immunostaining, respectively. Our results indicate that SFN-induced apoptosis was regulated by p53 and caspase-3 dependent pathways. Furthermore, SFN may act as a potent anti-proliferation agent, and as a promising candidate for molecular-targeting chemotherapy against human chondrosarcoma cells.

• Bulletin of the Korean Chemical Society
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• v.23 no.7
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• pp.1003-1010
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• 2002

Caspase 3, a member of cysteine protease family, is well known as a major apoptosis effector and is involved in cell death as a result of ischemic diseases such as stroke and myocardial infarction, therefore the inhibition of caspase 3 may protect those apoptotic cell damages. During the high-throughput screening of the compounds from the Korea Chemical Bank, berberine derivatives (A and B), an isoquinoline alkaloid, have been identified as potential inhibitors for caspase 3. Based on this finding we carried out molecular modeling study to identify the pharmacophoric elements of berberine structure which interact with a substrate-recognition binding site of caspase 3 and came up with several novel scaffolds. In this report, we will discuss the molecular modeling, syntheses and the enzyme inhibitory activities of these novel compounds.

• Journal of Nutrition and Health
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• v.37 no.1
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• pp.31-37
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• 2004

Curcumin, a natural compound extracted from rhizomes of Curcuma longa, has been shown to possess potent anti-inflammatory and anti-tumor activity. The mechanism by which curcumin initiates apoptosis remains poorly understood. In this study, we investigated the effects of curcumin on caspase-3 activity and protein expression of procaspase-3, Bcl-2, Bax, total Akt and phosphorylated Akt in SW480 human colon cancer cell. We cultured SW480 cells in the presence of various concentrations (0, 10, 20 or 30 uM) of curcumin. Curcumin inhibited colon cancer cell growth in a dose-dependent manner (p < 0.05). Caspase-3 activity was significantly increased dose-dependently in cells treated with curcumin (p < 0.05), concisely procaspase-3 expression was significantly decreased. Bcl-2 levels were decreased dose-dependently in cells treated with curcumin (p < 0.05), but Ben remained unchanged. In addition, phosphorylated Akt levels and total Akt levels were markedly lower in cells treated with 20 uM of curcumin treatment (p < 0.05), In conclusion, we have shown that curcumin inhibits cell growth and induces apoptosis in SW480 human colon cancer cell lines via Akt signal pathway.

• Journal of Life Science
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• v.20 no.4
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• pp.572-577
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• 2010

The purpose of this study was to find out the Bcl-2 (B-cell leukemia/lymphoma-2), Bax, and caspase-3(cysteine-aspartic proteases-3) protein expression in soleus and EDL muscle according to treadmill exercise intensity in 60 week-old SD rats. The SD rats were randomly divided into four groups (n=10 in each group): control (CON), low intensity exercise (LE), moderate intensity exercise (ME), and high intensity exercise (HE). The exercise was given to the rats for 8 wk, 5 day/wk. The animals underwent treadmill exercise at intensities of 30 min at 8 m/min for the LE group, 15 min at 16 m/min for the ME group, and 9 min at 24 m/min for the HE group. The results were as follows: the expression of Bcl-2 protein was lowest in the HE group and the expression of Bax protein was highest in the HE group. The expression of caspase-3 (cleaved form) protein was observed in the HE group. For the different types of muscle fiber, Bcl-2 protein expression in the soleus muscle was decreased in all groups. Bax protein expression in the soleus muscle was increased in the HE group only. Bcl-2 protein expression in the EDL muscle was decreased in the HE group, and Bax protein expression in the EDL muscle was increased in the ME and HE groups. Consequently, the protein expression related to the aged rats shows a difference according to the intensity of exercise. In addition, caspase-3 protein expression appeared in the HE group; however, in all amounts of intensity, DNA fragmentation was not observed. Therefore, apoptosis on skeletal muscles of aged mice can be intervened with optimal exercise. On the other hand, high intensity exercise can potentially accelerate the apoptosis of muscle fiber in aged rats.

• Journal of Physiology & Pathology in Korean Medicine
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• v.17 no.3
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• pp.751-758
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• 2003

In our previous studies, we reported that Selaginella Tamariscina(ST) induced apoptotic cell death in HL-60 cells selectively. The cell viability after treatment with extract of ST was quantified by MTT assay and trypan bleu exclusion method. The results showed that application with ST in HL-60 induced 40% cell death at the concentration of 400 ㎍/ml. The cancericidic effect of Selaginella Tamariscina was mediated by apoptosis. Thus, HL-60 cells exposed to Selaginella Tamariscina displayed the DNA fragmentation ladder and nucleus chromatin condensation characteristic for apoptosis. The enzyme activity of caspase-3 and actived caspase-3 protein were markedly increased in HL-60 cells treated with the extract of Selaginella Tamariscina. In addition, the extract of Selaginella Tamariscina induced cleavage of PARP, a known substrate for caspase-3. The expression of Bcl-2, anti-apoptotic protein, was decreased by treatment of the aqueous extract of Selaginella Tamariscina in a dose-dependent manner. And the expression of pro-apoptotic Bax protein was increased. In conclusion, our results suggest that the extract of Selaginella Tamariscina may induce the apoptotic death of HL-60 cells via activation of caspase-3, cleavage of PARP protein, depletion of cellular ATP levels and Bcl-2 degradation.

• Tuberculosis and Respiratory Diseases
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• v.56 no.4
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• pp.381-392
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• 2004

Arsenic trioxide($As_2O_3$) was introduced into the treatment of refractory or relapsed acute promyelocytic Ieukemia. Some investigators have reported that arsenic trioxide had induced apoptosis in a variety of solid human tumor cell lines, including non-small cell lung cancer. Non-steroidal anti-inflammatory drugs(NSAIDs) are powerful chemopreventive agents for gastrointestinal cancers and the growth of established tumors are reduced by inducing apoptosis. It's also reported that NSAIDs enhanced tumor response to chemotherapeutic drugs or radiation. In this study, we aimed to determine whether combination of arsenic trioxide with sulindac augmented its apoptotic potential in NCI-H157 human lung cancer cells. The human lung cancer cell line NCI-H157 was treated with arsenic trioxide and sulindac. Cell viability was measured by the MTT assay. Apoptosis was measured by nuclear staining and flow cytometric analysis. The catalytic activity of the caspase families were measured by the fluorogenic cleavage of biosubstrates. The western blotting were also performed to define the mechanical basis of apoptosis. Combination treatment of arsenic trioxide and sulindac decreased the viability of NCI-H157 human lung cancer cells in a dose-dependent manner. The catalytic activity of caspase-3, 8 and 9 proteases were increased after combination treatment. Consistently PARP was cleaved from 116kDa to 85kDa fragments, and the expression of ICAD was decreased by time-dependent manner. Also combination treatment increased the expression of Fas and Fas/L. Combination therapy of arsenic trioxide with sulindac augments cell death and induces apoptosis via the activation of caspase cascade in NCI-H157 human lung carcinoma cells.