• 생명과학회지
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• 제12권2호
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• pp.219-225
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• 2002

진핵세포의 염색체는 전사, 복제, 회복 등의 과정에서 관여하는 단백질의 기능으로 구조가 변하게 된다. 이때 관여하는 단백질은 DNA-단백질의 상호작용에 의해서 이루어지게 되는데, 이때 단백질의 일부분은 일정한 상동성이 존재하게 된다. 이러한 부분은 motif나 domain으로 구성되는데, 예를 들면, SAP domain등을 들 수 있다. S. pombe genomic DNA 데이터베이스를 검색하여 Arabidopsis PARP 과 KU70과 상동성을 보이는 새로운 유전자를 찾았다. 이를 SAPuvs (SAP UV Sensitive)라 명명하였으며, Ura4를 선별표지로 이용하여 S. pombe SAPuvs 유전자 결실세포를 구성하였다. SAPuvs 유전자 결실세포는 자외선 조사 실험에서 정상의 세포에 비해 현저하게 죽었다. 그러나, MMS 또는 MMS와 3AB의 처리 실험에서는 저항성을 보였다. 이러한 결과로 SAPuvs는 DNA 상해회복에서 염색사구조 형성에 연관되어 있음을 확인하였다.

• 한국발생생물학회지:발생과생식
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• 제2권2호
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• pp.165-171
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• 1998

p62는 임파구에 특이적으로 발현하는 단백질 티로신 키나제인 p56$^{lck}$의 SH2 doamin과 결합하는 세포질 단백질로서 두 단백질의 결합에는 지금까지 알려진 바와 다르게 인산화된 티로신이 필요없다. p62는 기능이 다른 여러 조직에서 공통적으로 발현되며 유비퀴틴, 단백질 키나제 C 이성질체 둥 다양한 단백질과 결합하는 것이 알려져 있다. 이와 같은 현상으로 p62가 다양한 생물학적 기능을 수행할 수 있음을 예측할 수 있으나 그 자세한 기작은 잘 알려져 있지 않다. 본 연구에서는 p62가 T-세포에 특이적으로 발현하는 14-3-3 $ au$ 이성질체와 결합하는 것을 확인하였으며, p62를 인위적으로 T-세포에 다량으로 발현시키면 세포예정사 (apoptosis)의 시작이 지연되는 현상을 조사하였다. 이때 세포사멸과정에서 전형적으로 나타나는 DNA 절단현상 (DNA fragmentaion)과 poly (ADP-ribose) polymerase의 분해가 지연됨을 알 수 있었다. 최근 14-3-3 단백질이 임파구에서 세포예정사를 촉진시키는 기능을 가진 Bad와 결합함으로써 세포의 생존 신호 전달에 중요한 역할을 한다는 것이 보고된 바 있다. 따라서 본 연구의 결과는 T-세포의 활성으로 일어나는 사멸예정사 과정 중에 p62와 14-3-3 단백질에 의해 수행되는 조절 기작이 있음을 시사하고 있다.다.

• BMB Reports
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• 제44권6호
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• pp.381-386
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• 2011

In the present study, we characterized the function of HS1-binding protein 3 (HS1BP3), which is mutated in essential tremor and may be involved in lymphocyte activation. We found that HS1BP3 localized to the mitochondria and endoplasmic reticulum partially. Overexpression of HS1BP3 induced apoptosis in HEK293T and HeLa cell lines. When these cell lines were transfected with HS1BP3, they exhibited nuclear DNA condensation, externalization of phosphatidylserine (PS), and cleavage of poly ADP ribose polymerase (PARP). Furthermore, suppression of HS1BP3 or HS1 expression attenuates HS1BP3 induced apoptosis. In addition, HS1BP3 enhanced activator protein 1 (AP-1)-mediated transcription in a dose-dependent manner. Therefore, we conclude that HS1BP3 regulates apoptosis via HS1 and stimulates AP-1-mediated transcription.

• Journal of Chest Surgery
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• 제45권1호
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• pp.1-10
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• 2012

Background: ${\alpha}$-Lipoic acid (${\alpha}$-LA) has been studied as an anticancer agent as well as a therapeutic agent for diabetes and obesity. We performed this study to evaluate the anticancer effects and mechanisms of ${\alpha}$-LA in a lung cancer cell line, A549. Materials and Methods: ${\alpha}$-LA-induced apoptosis of A549 cells was detected by fluorescence-activated cell sorting analysis and a DNA fragmentation assay. Expression of apoptosis-related genes was analyzed by western blot and reverse transcription.polymerase chain reaction analyses. Results: ${\alpha}$-LA induced apoptosis and DNA fragmentation in A549 cells in a dose- and time-dependent manner. ${\alpha}$-LA increased caspase activity and the degradation of poly (ADP-ribose) polymerase. It induced expression of endoplasmic reticulum (ER) stress-related genes, such as glucose-regulated protein 78, C/EBP-homologous protein, and the short form of X-box binding protein-1, and decreased expression of the anti-apoptotic protein, X-linked inhibitor of apoptosis protein. Reactive oxygen species (ROS) production was induced by ${\alpha}$-LA, and the antioxidant N-acetyl-L-cysteine decreased the ${\alpha}$-LA-induced increase in expression of apoptosis and ER stress-related proteins. Conclusion: ${\alpha}$-LA induced ER stress-mediated apoptosis in A549 cells via ROS. ${\alpha}$-LA may therefore be clinically useful for treating lung cancer.

• 생명과학회지
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• 제29권3호
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• pp.295-302
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• 2019

Liquiritigenin (LG)은 licorice 뿌리에서 분리된 chiral flavonoid이다. LG는 항산화, 항암 및 항염증 효과를 포함하여 다양한 생물학적 활성을 가지고 있다. 구강편평세포암종에서 LG의 항암 활성은 아직 밝혀지지 않았다. 본 연구에서는 구강편평상피암 세포(HN22)에서 LG의 항암 효능을 시험하였다. HN22 세포에 LG를 처리하여 MTT 분석으로 세포 생존율을 평가하였으며, Annecin V/7-Aminactinomycin D 염색, 세포주기 및 Multi-caspase 활성을 $Muse^{TM}$ cell Analyzer로 분석하여 세포사멸 유도를 확인하였다. 분석결과, 구강편평상피암 HN22 세포에 LG를 처리시 G2/M 세포주기 정지를 일으켰으며, Western blotting 통하여 cyclin B1 및 CDC2 발현 감소와 p27 발현 증가를 확인하였다. LG는 활성산소종의 생성을 유발하고, CCAAT/enhancer-binding protein homologous protein (CHOP) 및 78-kDa glucose regulated protein (GRP78)의 발현을 농도의존적으로 유도하였다. HN22 세포에 LG의 처리는 미토콘드리아 막전위의 손실(${\Delta}{\Psi}m$)을 일으켰다. LG를 처리한 HN22 세포의 단백질 분석결과 apoptotic protease activating factor-1 (Apaf-1), cleaved Poly (ADP-Ribose) Polymerase (C-PARP) 및 Bax의 발현을 증가함을 확인하였다. 따라서 우리의 결과는 LG이 구강편평상피암 세포의 세포사멸을 유도하여 항암제 역할을 할 수 있는 천연 화합물임을 시사한다.

• 대한화학회지
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• 제66권4호
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• pp.298-304
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• 2022

The present study was designed to investigate the molecular mechanisms of DK-5-62, a novel (-)-catechin derivative on HCT116 human colorectal cancer cells. DK-5-62 inhibited the proliferation in dose- and time-dependent manner accompanied by the morphological changes. Effects of DK-5-62 appeared to be mediated by the induction of apoptosis, as manifested through DNA-binding dye Hoechst 33258 staining. Analysis of the mechanism of these events indicated that DK-5-62-treated cells exhibited an increased ratio of Bax/Bcl-2, resulting in the activation of caspase-9, caspase-3, and poly-ADP-ribose polymerase in a dose-dependent manner. Moreover, DK-5-62-induced apoptosis was accompanied by phosphorylation of the mitogen-activated protein kinase family, c-Jun N-terminal kinase, p38, and extracellular signal-regulated kinase. These results suggest that HCT116 cells are moderately sensitive to growth inhibition by DK-5-62 via apoptosis, as evidenced by activation of ERK/p38/Bcl-2 family signaling, as well as alteration in caspase-9 and caspase-3.

• 동의생리병리학회지
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• 제23권5호
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• pp.1154-1160
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• 2009

Androgen receptors (AR) play a crucial role in the development and progression of prostate cancer. Many studies have suggested that prostate cancer cell proliferation is inhibited by AR downregulation, and it has been reported that Takrisodokyeum (TRSDY) induced apoptotic cell death and suppressed tumorigenesis in human leukemia cells. Therefore, this study was conducted to elucidate the mechanism by which TRSDY affects cell growth and AR expression in androgen-dependent prostate cancer cells (LNCaP cells). We investigated the proliferation and apoptosis of LNCaP cells using MTT and DNA fragmentation assays. In addition, we used western blot analysis to assess the effects of TRSDY on the expression of the AR target gene, prostate-specific antigen (PSA). Furthermore, the mechanism of AR downregulation by TRSDY was investigated using EMSA to analyze the binding activity of AR to androgen response elements (ARE). TRSDY significantly suppressed proliferation and induced apoptosis in LNCaP cells. In addition, TRSDY-induced apoptotic cell death was accompanied by activation of caspase-3 and cleavage of its substrate, poly(ADP-ribose) polymerase. TRSDY also inhibited the constitutively expressed- or 5a-dihydrotestosterone (DHT)-induced AR/PSA protein levels. However, these effects were mediated by inhibition of the binding of AR to ARE. TRSDY-mediated AR/PSA downregulation contributes to the inhibition of cell proliferation and the induction of apoptosis in LNCaP human prostate cancer cells. Our findings suggest that TRSDY may be used as a chemopreventive or chemotherapeutic agent for the treatment of prostate cancer.

• BMB Reports
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• 제36권2호
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• pp.223-229
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• 2003

The product of a tree (Tabebuia avellanedae) from South America, $\beta$-lapachone, is known to exhibit various pharmacological properties, the mechanisms of which are poorly understood. The aim of the present study was to further elucidate the possible mechanisms by which $\beta$-lapachone exerts its anti-proliferative action in cultured human prostate cancer cells. We observed that the proliferation-inhibitory effect of $\beta$-lapachone was due to the induction of apoptosis, which was confirmed by observing the morphological changes and cleavage of the poly(ADP-ribose) polymerase protein. A DNA flow cytometric analysis also revealed that $\beta$-lapachone arrested the cell cycle progression at the G1 phase. The effects were associated with the down-regulation of the phosphorylation of the retinoblastoma protein (pRB) as well as the enhanced binding of pRB and the transcription factor E2F-1. Also, $\beta$-lapachone suppressed the cyclindependent kinases (Cdks) and cyclin E-associated kinase activity without changing their expressions. Furthermore, this compound induced the levels of the Cdk inhibitor $p21^{WAF1/CIP1}$ expression in a p53-independent manner, and the p21 proteins that were induced by $\beta$-lapachone were associated with Cdk2. $\beta$-lapachone also activated the reporter construct of a p21 promoter. Overall, our results demonstrate a combined mechanism that involves the inhibition of pRB phosphorylation and induction of p21 as targets for $\beta$-lapachone. This may explain some of its anticancer effects.

• The Korean Journal of Physiology and Pharmacology
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• 제5권4호
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• pp.287-297
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• 2001

Contraction of smooth muscle is initiated by an increase in cytosolic $Ca^{2+}$ leading to activation of $Ca^{2+}$/ calmodulin-dependnet myosin light chain (MLC) kinase and phosphorylation of MLC. The types of contraction and signaling mechanisms mediating contraction differ depending on the region. The involvement of these different mechanisms varies depending on the source of $Ca^{2+}$ and the kinetic of $Ca^{2+}$ mobilization. $Ca^{2+}$ mobilizing agonists stimulate different phospholipases $(PLC-{\beta},\;PLD\;and\;PLA_2)$ to generate one or more $Ca^{2+}$ mobilizing messengers $(IP_3\;and\;AA),$ and diacylglycerol (DAG), an activator of protein kinase C (PKC). The relative contributions of $PLC-{\beta},\;PLA_2$ and PLD to generate second messengers vary greatly between cells and types of contraction. In smooth muscle cell derived form the circular muscle layer of the intestine, preferential hydrolysis of $PIP_2$ and generation of $IP_3$ and $IP_3-dependent\;Ca^{2+}$ release initiate the contraction. In smooth muscle cells derived from longitudinal muscle layer of the intestine, preferential hydrolysis of PC by PLA2, generation of AA and AA-mediated $Ca^{2+}$ influx, cADP ribose formation and $Ca^{2+}-induced\;Ca^{2+}$ release initiate the contraction. Sustained contraction, however, in both cell types is mediated by $Ca^{2+}-independent$ mechanism involving activation of $PKC-{\varepsilon}$ by DAG derived form PLD. A functional linkage between $G_{13},$ RhoA, ROCK, $PKC-{\varepsilon},$ CPI-17 and MLC phosphorylation in sustained contraction has been implicated. Contraction of normal esophageal circular muscle (ESO) in response to acetylcholine (ACh) is linked to $M_2$ muscarinic receptors activating at least three intracellular phospholipases, i.e. phosphatidylcholine-specific phospholipase C (PC-PLC), phospholipase D (PLD) and the high molecular weight (85 kDa) cytosolic phospholipase $A_2\;(cPLA_2)$ to induce phosphatidylcholine (PC) metabolism, production of diacylglycerol (DAG) and arachidonic acid (AA), resulting in activation of a protein kinase C (PKC)-dependent pathway. In contrast, lower esophageal sphincter (LES) contraction induced by maximally effective doses of ACh is mediated by muscarinic $M_3$ receptors, linked to pertussis toxin-insensitive GTP-binding proteins of the $G_{q/11}$ type. They activate phospholipase C, which hydrolyzes phosphatidylinositol bisphosphate $(PIP_2),$ producing inositol 1, 4, 5-trisphosphate $(IP_3)$ and DAG. $IP_3$ causes release of intracellular $Ca^{2+}$ and formation of a $Ca^{2+}$-calmodulin complex, resulting in activation of myosin light chain kinase and contraction through a calmodulin-dependent pathway.

• Natural Product Sciences
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• 제26권3호
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• pp.191-199
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• 2020

Fucoidan, a natural component of brown seaweed, has various biological activities such as anti-cancer activity, anti-oxidant, and anti-inflammatory against various cancer cells. However, the fucoidan has been implicated in melanoma cells via apoptosis signaling pathway. Therefore, we investigated apoptosis with fucoidan in A2058 human melanoma cells with dose- and time-dependent manners. In our results, A2058 cells viability decreased at relatively short-time and low-concentration through fucoidan. This effects of fucoidan on A2058 cells appeared to be mediated by the induction of apoptosis, as manifested by morphological changes through DNA-binding dye Hoechst 33342 staining. When a dose of 80 ㎍/mL fucoidan was treated, the cells were observed: crescent or ring-like structure, chromatin condensation, and nuclear fragmentation. With the increase at 100 ㎍/mL fucoidan, the cell membrane is intact throughout the total process, including membrane blebbing and loss of membrane integrity as well as increase of sub-G1 DNA. Furthermore, to understand the exact mechanism of fucoidan-treated in A2058 cells, western blotting was performed to detect apoptosis-related protein expression. In this study, Bcl-2 family proteins can be regulated by fucoidan, suggesting that fucoidan-induced apoptosis is modulated by intrinsic pathway. Therefore, expression of Bcl-2 and Bax may result in altered permeability, activating caspase-3 and caspase-9. And the cleaved form of poly ADP-ribose polymerase was detected in fucoidan-treated A2058 cells. These results suggest that A2058 cells are highly sensitive to growth inhibition by fucoidan via apoptosis, as evidenced by activation of extracellular signal-regulated kinases/p38/Bcl-2 family signaling, as well as alteration in caspase-9 and caspase-3.