• Asian Pacific Journal of Cancer Prevention
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• 제14권7호
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• pp.4249-4254
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• 2013

Background: Parafibromin is a protein encoded by the HRPT2 (hyperparathyroidism 2) oncosuppressor gene and its down-regulated expression is involved in pathogenesis of parathyroid, breast, gastric and colorectal carcinomas. This study aimed to clarify the effects of parafibromin expression on the phenotypes and relevant mechanisms of DLD-1 colon carcinoma cells. Methods: DLD-1 cells transfected with a parafibromin-expressing plasmid were subjected to examination of phenotype, including proliferation, differentiation, apoptosis, migration and invasion. Phenotype-related proteins were measured by Western blot. Parafibromin and ki-67 expression was detected by immunohistochemistry on tissue microarrays. Results: The transfectants showed higher proliferation by CCK-8, better differentiation by electron microscopy and ALP activity and more apoptotic resistance to cisplatin by DNA fragmentation than controls. There was no difference in early apoptosis by annexin V, capase-3 activity, migration and invasion between DLD-1 cells and their transfectants. Ectopic parafibromin expression resulted in down-regulated expression of smad4, MEKK, GRP94, GRP78, $GSK3{\beta}$-ser9, and Caspase-9. However, no difference was detectable in caspase-12 and -8 expression. A positive relationship was noted between parafibromin and ki-67 expression in colorectal carcinoma. Conclusions: Parafibromin overexpression could promote cell proliferation, apoptotic resistance, and differentiation of DLD-1 cells.

• BMB Reports
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• 제45권8호
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• pp.482-487
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• 2012

To identify the novel inhibitors of endoplasmic reticulum stress-induced cell death, we performed a high throughput assay with a chemical library containing a total of 3,280 bioactive small molecules. Cyclosporine A and bromocriptine were identified as potent inhibitors of thapsigargiin-induced cell death (cut-off at $4{\sigma}$ standard score). However, U74389G, the potent inhibitor of lipid peroxidation had lower activity in inhibiting cell death. The inhibition effect of cyclosporine A and bromocriptine was specific for only thapsigargin-induced cell death. The mechanism of inhibition by these compounds was identified as modification of the expression of glucose regulated protein-78 (GRP-78/Bip) and inhibition of phosphorylation of p38 mitogen activated protein kinase (MAPK). However, these compounds did not inhibit the same events triggered by tunicamycin, which was in agreement with the cell survival data. We suggest that the induction of protective unfolded protein response by these compounds confers resistance to cell death. In summary, we identified compounds that may provide insights on cell death mechanisms stimulated by ER stress.

• 생명과학회지
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• 제25권8호
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• pp.947-952
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• 2015

Par-4는 종양 억제 유전자로 암세포 선택적으로 세포사멸을 증진하는 기능을 가진다. Par-4 유전자는 nuclear localization sequences (NLS), leucine zipper (LZ), nuclear export sequence (NES), selective for apoptosis in cancer cells (SAC)의 네 가지 도메인을 가지고 있다. 이 중에서도 SAC 도메인이 Par-4에 의한 세포사멸에 중요한 역할을 하며, 이러한 Par-4의 활성화는 세포 내 경로와 세포 외 경로로 나누어진다. 세포질 내의 Par-4는 핵 내로 이동하여 NF-κB 매개의 세포 성장 경로를 억제하고 세포 밖으로 분비된 Par-4는 세포 표면에 존재하는 수용체인 GRP78과 결합하여 세포 사멸을 유도한다. 따라서 Par-4의 발현을 증가시키는 물질에 의한 세포 사멸뿐만 아니라 암세포에서 발현이 낮은 Par-4의 과발현을 통하여 세포사멸 민감화가 증진된다. 따라서 Par-4는 암 치료의 강력한 표적으로의 가능성을 가지고 있다.

• 생명과학회지
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• 제32권10호
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• pp.771-777
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• 2022

파킨슨병에서의 도파민 신경세포의 사멸 원인은 다양하며 별개의 유전적 요소와 환경적 요소들이 관여한다. 드물게 발생하는 유전성 파킨슨병에서 parkin의 돌연변이와 기능 상실은 주로 소포체 스트레스를 통해 중뇌 흑질의 도파민 신경세포를 특이적으로 손상시킨다. 상대적으로 일반적인 특발성 파킨슨병에서는 살충제 노출이 역학적으로 중요하다. 그러나 환경독성물질에의 노출과 유전성 파킨슨병의 연관성에 대해서는 잘 알려진 바가 없다. 본 연구에서는 잘 확립된 중뇌 유래의 도파민 신경세포주인 N27-A를 사용하여 특발성 파킨슨병과 유전성 파킨슨병 사이의 공통된 발병 기작의 증거를 확인하였다. 특발성 파킨슨병을 유발하는 유기염소계 살충제인 디엘드린은 BiP/Grp78, 헴산화효소-1과 같은 소포체 스트레스 반응 표지자를 발현 유도하였고, 특히 parkin 단백질의 발현을 증가시켰다. 디엘드린이 N27-A 세포를 사멸시키는 과정에서 소포체 스트레스 특이적 세포사를 매개하는 Caspase-12의 활성화가 유의미하게 증가하였다. 흥미롭게도 디엘드린에 의한 N27-A 세포의 사멸이 소포체 단백질인 parkin과 Bcl-2의 과발현시 유의미하게 억제되었다. 본 연구 결과, 소포체 스트레스의 누적이 특발성, 유전성 파킨슨병의 공통의 발병 기작일 가능성이 있으며, 몇 가지 소포체 관련 단백질들이 디엘드린에 의한 도파민 신경세포 손상으로부터 보호 효과를 가지는 것으로 보인다.

• BMB Reports
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• 제51권8호
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• pp.400-405
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• 2018

Chronic stress induces neuronal cell death, which can cause nervous system disorders including Parkinson's disease and Alzheimer's disease. In this study, we evaluated the neuroprotective effects of Clematis terniflora extract (CTE) against corticosterone-induced apoptosis in rat pheochromocytoma (PC12) cells, and also investigated the underlying molecular mechanisms. At concentrations of 300 and $500{\mu}g/ml$, CTE significantly decreased apoptotic cell death and mitochondrial damage induced by $200{\mu}M$ corticosterone. CTE decreased the expression levels of endoplasmic reticulum (ER) stress proteins GRP78, GADD153, and mitochondrial damage-related protein BAD, suggesting that it downregulates ER stress evoked by corticosterone. Furthermore, our results suggested that these protective effects were mediated by the upregulation of p-AKT and p-ERK1/2, which are involved in cell survival signaling. Collectively, our results indicate that CTE can lessen neural damage caused by chronic stress.

• BMB Reports
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• 제42권11호
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• pp.719-724
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• 2009

Recent studies have revealed that endoplasmic reticulum (ER) disturbance is involved in the pathophysiology of neurodegenerative disorders, contributing to the activation of the ER stress-mediated apoptotic pathway. Therefore, we investigated here the molecular mechanisms underlying the ER-mitochondria axis, focusing on calcium as a potential mediator of cell death signals. Using NT2 cells treated with brefeldin A or tunicamycin, we observed that ER stress induces changes in the mitochondrial function, impairing mitochondrial membrane potential and distressing mitochondrial respiratory chain complex Moreover, stress stimuli at ER level evoked calcium fluxes between ER and mitochondria. Under these conditions, ER stress activated the unfolded protein response by an overexpression of GRP78, and also caspase-4 and-2, both involved upstream of caspase-9. Our findings show that ER and mitochondria interconnection plays a prominent role in the induction of neuronal cell death under particular stress circumstances.

• Molecules and Cells
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• 제25권1호
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• pp.43-49
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• 2008

Cancer Osaka thyroid, also known as Tpl-2 (Cot) is a member of the MAP3K kinase family and plays a key role in the regulation of the immune response to pro-inflammatory stimuli such as lipopolysaccharide (LPS) and tumour necrosis $factor-{\alpha}$ ($TNF-{\alpha}$). A series of Cot constructs with an N-terminal 6xHis tag were transiently expressed in HEK293 cells: $Cot_{130-399}$ (kinase domain), $Cot_{1-388}$ (N-terminal and kinase do-mains), $Cot_{1-413}$, $Cot_{1-438}$ (containing a putative PEST sequence), $Cot_{1-457}$ (containing both PEST and degron sequences) and $Cot_{1-467}$ (full-length protein). These Cot proteins were pulled down using an anti-6xHis antibody and separated by 2D electrophoresis. The gels were silver-stained and 21 proteins were detected that did not appear, or had substantially reduced intensity, in the control sample. Three of these were identified by MS and MS/MS analysis as Hsp90, Hsp70 and Grp78. Hsp90 appeared to bind to the kinase domain of Cot and this interaction was further investigated using co-immuno-precipitation with both overexpressed Cot in HEK293 cells and endogenous Cot in Hela cells.

• 동의생리병리학회지
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• 제26권3호
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• pp.287-292
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• 2012

The results of this study intended to clarify the apoptotic effects of curcumin on Epstein-Barr virus transformed human B lymphoma (EBV-B) cells are summarized as follows: It was found that curcumin induced endoplasmic reticulum(ER) stress as well as apoptotic cell death in EBV-B cells, although the magnitude of action was insignificant. When EBV-B cells activated by pokeweed mitogen (PWM) were treated with the same concentrations of curcumin, it was found that higher ER stress (GRP78, P-PERK, XBP-1, ATF6, and CHOP expressed) increased unfold protein response (UPR) and thus, apoptosis attributed to ER stress, compared to non-activated EBV-B cells In conclusion, it is expected that curcumin will play an important role for leukemia treatment.

• Asian Pacific Journal of Cancer Prevention
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• 제13권5호
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• pp.1977-1981
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• 2012

Houttuynia cordata Thunb (HCT) is a native herb found in Southeast Asia which features various pharmacological activities against allergy, inflammation, viral and bacterial infection, and cancer. The aims of this study were to determine the cytotoxic effect of 6 fractions obtained from silica gel column chromatography of alcoholic HCT extract on human leukemic Molt-4 cells and demonstrate mechanisms of cell death. Six HCT fractions were cytotoxic to human lymphoblastic leukemic Molt-4 cells in a dose-dependent manner by MTT assay, fraction 4 exerting the greatest effects. Treatment with $IC_{50}$ of HCT fraction 4 significantly induced Molt-4 apoptosis detected by annexinV-FITC/propidium iodide for externalization of phosphatidylserine to the outer layer of cell membrane. The mitochondrial transmembrane potential was reduced in HCT fraction 4-treated Molt-4 cells. Moreover, decreased expression of Bcl-xl and increased levels of Smac/Diablo, Bax and GRP78 proteins were noted on immunoblotting. In conclusion, HCT fraction 4 induces Molt-4 apoptosis cell through an endoplasmic reticulum stress pathway.

• The Korean Journal of Physiology and Pharmacology
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• 제15권6호
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• pp.345-351
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• 2011

High glucose leads to physio/pathological alterations in diabetes patients. We investigated collagen production in human gingival cells that were cultured in high concentrations of glucose. Collagen synthesis and secretion were increased when the cells were exposed to high concentrations of glucose. We examined endoplasmic reticulum (ER) stress response because glucose metabolism is related to ER functional status. An ER stress response including the expression of glucose regulated protein 78 (GRP78), C/EBP homologous protein (CHOP), inositol requiring enzyme alpha (IRE-$1{\alpha}$) and phosphoreukaryotic initiation factor alpha (p-eIF-$2{\alpha}$) was activated in the presence of high glucose. Activating transcription factor 4 (ATF-4), a downstream protein of p-eIF-$2{\alpha}$ as well as a transcription factor for collagen, was also phosphorylated and translocalized into the nucleus. The chemical chaperone 4-PBA inhibited the ER stress response and ATF-4 phosphorylation as well as nuclear translocation. Our results suggest that high concentrations of glucose-induced collagen are linked to ER stress and the associated phosphorylation and nuclear translocation of ATF-4.