• BMB Reports
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• v.39 no.1
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• pp.97-104
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• 2006

Endostatin is a tumor-derived angiogenesis inhibitor, and the endogenous 20 kDa carboxyl-terminal fragment of collagen XVIII. In addition to inhibiting angiogenesis, endostatin inhibits tumor growth and the induction of apoptosis in several endothelial cell types. However, the mechanisms that regulate endostatin-induced apoptotic cell death are unclear. Here, we investigated apoptotic cell death and the underlying regulatory mechanisms elicited of endostatin in human umbilical vein endothelial cells (HUVECs). Endostatin was found to induce typical apoptotic features, such as, chromatin condensation and DNA fragmentation in these cells. Thus, as the phosphoinositide 3-OH kinase (PI3K)/protein kinase B (PKB) signaling pathway has been shown to prevent apoptosis in various cell types, we investigated whether this pathway could protect cells against endostatin induced apoptosis. It was found that the inhibition of PI3K/PKB significantly increased endostatin-induced apoptosis, and that endostatin-induced cell death is physiologically linked to PKB-mediated cell survival through caspase-8.

• The Journal of Korean Medicine
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• v.21 no.4
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• pp.183-192
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• 2000

Objectives : The present study was carried out to investigate the effects of Danchun-hwan(DCH) on the peroxynitrite-induced neural cell death in human neuroblastoma cell line, SH-SY5Y. Methods : The cultured cells were pretreated with DCH and exposed to 3-morpholinosydnonimine(SIN-1) that simultaneously generates NO and superoxide, thus possibly forming peroxynitrite. The cell damage was assessed by using MTT assay and crystal violet staining. Results : Exposure of the cells to SIN-1 for 24hr induced 75% apoptotic cell death, as evaluated by the occurrence of morphological nuclear changes characteristic of apoptosis using 4', 6-diamidino-2-phenylinole(DAPI). However, pretreatment of SH-SY5Y with the water extracts of DCH, inhibited the apoptotic cell death in a dose-dependent manner. DCH also inhibited SIN-1-induced apoptotic caspase 3-like protease activity in a dose-dependent manner. DCH recovered the depleted glutathione levels by SIN-1. Conclusions : Taken together, it is suggested that DCH protected human neuroblastoma cell line, SH-SY5Y, from the free radical injury mediated by peroxynitrite by a mechanism of elevating antioxidant, GSH.

• Journal of Microbiology and Biotechnology
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• v.15 no.5
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• pp.913-918
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• 2005

Chloramphenicol is a broad-spectrum antimicrobial agent against Gram (+) and Gram (-) bacteria. Its clinical application has recently been limited, due to severe side effects such as bone marrow suppression and aplastic anemia. In the present study, the cytotoxic effects of chloramphenicol were investigated in vitro using chronic myelogenous leukemia K562 cells. Chloramphenicol inhibited the growth of K562 cells in a dose-dependent manner, but their growth was restored after the cessation of chloramphenicol, indicating reversible cytotoxic effects. The expression of cell cycle regulatory molecules, including E2F-1 and cyclin D1, was decreased at the translational and/or transcriptional level after being treated with a therapeutic blood level ($20{\mu}g/ml$) of chloramphenicol. Chloramphenicol also induced apoptotic cell death through a caspase-dependent pathway, which was verified by Western blot analysis and the enzymatic activity of caspase-3. These results demonstrated that chloramphenicol inhibited the cell growth through arresting the transition of the cell cycle, and induced apoptotic cell death through a caspase-dependent pathway at therapeutic concentrations.

• YAKHAK HOEJI
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• v.46 no.1
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• pp.18-23
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• 2002

Ailanthus altissima has been used to settle an upset stomach, to alleviate a fever and as an insecticide. We reported that the water extract of A. altissima induced apoptotic cell death in Jurkat T-acute Iymphoblastic leukemia cells. Here, we showed the dose-dependent inhibitions of cell viability by the extract, as measured by cell morphology. The cell cycle control genes are considered to play important roles in tumorigenesis. The purpose of the present study is also to investigate the effect of A. altissima on cell cycle progression and its molecular mechanism in the cells. The level of p21 protein was increased after treatment of the extract, whereas both Bcl-2 and Bax protein levels were not changed. These results suggest that A. altissima induces apoptotic cell death via p21-dependent signaling pathway in Jurkat cells which delete wild type p53. Gl checkpoint related gene products tested (cyclin D3, cyclin dependent kinase 4, retinoblastoma, E2Fl) were decreased in their protein levels in a dose-dependent manner after treatment of the extract Taken together, these results indicate that the increase of apoptotic cell death by A. altissima may be due to the inhibition of cell cycle in Jurkat cells.

• BMB Reports
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• v.38 no.6
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• pp.639-645
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• 2005

Protein kinase C (PKC) isozymes, a family of serine-threonine kinases, are important regulators of cell proliferation and malignant transformation. Phorbol esters, the prototype PKC activators, cause PKC translocation to the plasma membrane in prostate cancer cells, and trigger an apoptotic response. Studies in recent years have determined that each member of the PKC family exerts different effects on apoptotic or survival pathways. $PKC{\delta}$, one of the novel PKCs, is a key player of the apoptotic response via the activation of the p38 MAPK pathway. Studies using RNAi revealed that depletion of $PKC{\delta}$ totally abolishes the apoptotic effect of the phorbol ester PMA. Activation of the classical $PKC{\alpha}$ promotes the dephosphorylation and inactivation of the survival kinase Akt. Studies have assigned a pro-survival role to $PKC{\varepsilon}$, but the function of this PKC isozyme remains controversial. Recently, it has been determined that the PKC apoptotic effect in androgen-dependent prostate cancer cells is mediated by the autocrine secretion of death factors. $PKC{\delta}$ stimulates the release of $TNF{\alpha}$ from the plasma membrane, and blockade of $TNF{\alpha}$ secretion or $TNF{\alpha}$ receptors abrogates the apoptotic response of PMA. Molecular analysis indicates the requirement of the extrinsic apoptotic cascade via the activation of death receptors and caspase-8. Dissecting the pathways downstream of PKC isozymes represents a major challenge to understanding the molecular basis of phorbol ester-induced apoptosis.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.27 no.6
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• pp.511-518
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• 2001

The effect of mycolactone, a recently reported apoptosis-inducing factor, was investigated in SCC15 oral squamous cell carcinoma(OSCC) cell line. Mycolactone rapidly induced cell death in OSCC cells in 2days, which was similar to that found in apoptotic cell such as detaching from culture plate and rounding-up of cells. Apoptotic cells were increased 4hrs after mycolactone treatment and more than half of cells showed apoptosis after 72hrs. Caspase 3 activation a biochemical evidence of apoptosis, was determined by Western blotting. Caspase 3 activation was started at 2hrs that lasted until 8hrs after mycolactone treatment. The expression of bcl-2 family genes was determined to explain the mechanism of apoptosis found in OSCC cells. The expressions of bad, bak, and bax (pro-apoptotic genes) and bcl-w and bcl-2 genes (anti-apoptotic genes) were not changed by mycolactone treatment. The expression of bcl-xi was decreased 8 hrs after mycolactone treatment. Mcl-1 expression was initially increased at 2 hrs which was decreased 8 hrs after mycolactone treatment. The down-regulation of these two anti-apoptotic genes might explain the mycolactone-induced apoptosis in OSCC cells. In this study, mycholactone was revealed to induce cell death in OSCC cells apoptosis and the apoptosis mechanism of OSCC cells was shown to be down-regulation of anti-apoptotic genes, bcl-xi and mcl-1. These results suggested the applicability of mycolactone for the development of an anti-cancer drug candidate by inducing apoptosis of OSCC cancer cell.

• International Journal of Oral Biology
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• v.31 no.3
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• pp.81-86
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• 2006

SET (Suppressor of variegation, Enhancer of zeste, and the Trithorax) domain-containing proteins are known to have methyltransferase activity at lysine residues of histone proteins. In this study, we identified a novel SET domain-containing protein from mouse and named Kodo7. Indeed, Kodo7 has methyltransferase activity at K9 residue of the H3 protein as demonstrated by a histone methyl-transferse activity assay using GST-tagged Kodo7. Confocal microscopy showed that Kodo7 is co-localized with histones in the nucleus. Interestingly, ectopic expression of Kodo7 by transient transfection induced cell death and treatment of the transfectants with a caspase-3 inhibitor, Ac-DEVD-AFC decreased Kodo7-induced apoptosis. These results suggest that Kodo7 induces apoptotic cell death through increased methylation of histones leading to transcriptional repression.

• The Journal of Korean Medicine
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• v.26 no.4
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• pp.87-97
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• 2005

Backgrounds: Intracerebral hemon-hage is one of the most devastating types of stroke. Ginseng radix, the root of Panax Ginseng, C. A. MEYER (Araliaceae), is one of the most famous medicinal herbs with various therapeutic applications. Objectives: In the present study, the effect of aqueous extract of Ginseng radix on intracerebral hemorrhage-induced neuronal cell death in rats was investigated. Materials and Methods: Step-down avoidance task, Nissl staining, immunohistochemistry for caspase-3 and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay were used for this study. Results: The present results show that hemorrhage-induced lesion volume and apoptotic neuronal cell death in the striatum were significantly suppressed by treatment with Ginseng radix, resulting in enhancement of short-ten-n memory. Conclusions: We have shown that Ginseng radix has a neuroprotective effect on stroke, and aids the recovery from central nervous system sequelae following stroke.

• Archives of Pharmacal Research
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• v.27 no.8
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• pp.834-839
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• 2004

In human neuroblastoma SK-N-BE(2) cells undergoing apoptotic death induced by ginsenos-ide Rh2, a dammarane glycoside that was isolated from Panax ginseng C. A. Meyer, caspase-1 and caspase-3 were activated. The expression of Bax was increased in the cells treated with ginsenoside Rh2, whereas Bcl-2 expression was not altered. Treatment with caspase-1 inhibi-tor, Ac-YVAD-CMK, or caspase-3 inhibitor, Z-DEVD-FMK, partially inhibited ginsenoside Rh2-induced cell death but almost suppressed the cleavage of the 116 kDa PARP into a 85 kDa fragment. When the levels of p53 were examined in this process, p53 accumulated rapidly in the cells treated early with ginsenoside Rh2. These results suggest that activation of caspase-1 and -3 and the up-regulation of Bax are required in order for apoptotic death of SK-N-BE(2) cells to be induced by ginsenoside Rh2, and p53 plays an important role in the pathways to promote apoptosis.

• BMB Reports
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• v.35 no.1
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• pp.24-27
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• 2002

Apoptotic cell death is an active process mediated by various signaling pathways, which include the caspase cascade and the stress-activated protein kinase pathways. The caspase cascade is activated by two distinct routes: one from cell surface and the other from mitochondria. Activation of the route from cell surface requires the cellular components that include membrane receptors, adaptor proteins such as TRADD and FADD, and caspase-8, while activation of the other from mitochondria requires Apaf-1, caspase-9, and cytosolic cytochrome c. On the other hand, persistent stimulation of the stress-activated protein kinase pathway is also shown to mediate apoptosis in many cell types. Gene-targeting studies with jnk- or jip-null mice, in particular, strongly suggest that this signaling pathway plays a pivotal role in the cellular machinery for apoptosis.