• BMB Reports
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• 제49권5호
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• pp.270-275
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• 2016

The Ubiquitin proteasome system (UPS) plays roles in protein degradation, cell cycle control, and growth and inflammatory cell signaling. Dysfunction of UPS in cardiac diseases has been seen in many studies. Cholesterol acts as an inducer of cardiac hypertrophy. In this study, the effect of proteasome inhibitors on the cholesterol-induced hypertrophic growth in H9c2 cells is examined in order to observe whether UPS is involved in cardiac hypertrophy. The treatment of proteasome inhibitors MG132 and Bortezomib markedly reduced cellular surface area and mRNA expression of β-MHC in cholesterol-induced cardiac hypertrophy. In addition, activated AKT and ERK were significantly attenuated by MG132 and Bortezomib in cholesterol-induced cardiac hypertrophy. We demonstrated that cholesterol-induced cardiac hypertrophy was suppressed by proteasome inhibitors. Thus, regulatory mechanism of cholesterol-induced cardiac hypertrophy by proteasome inhibitors may provide a new therapeutic strategy to prevent the progression of heart failure.

• The Plant Pathology Journal
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• 제27권3호
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• pp.225-231
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• 2011

Previously, we identified the 20S proteasome ${\alpha}$-subunit of Magnaporthe oryzae (M. oryzae) induced during appressorium formation, and detected an increase in multiple protein ubiquitination during the early appressorium formation process (Kim et al., 2004). In this study, we further attempted to determine whether the proteasome is involved in the appressorium formation of M. oryzae both in vitro and in planta, using proteasome inhibitors. A significant increase in 20S proteasome during fungal germination and appressorium formation was observed using Western blot analysis with 20S proteasome antibody, demonstrating that proteasome-mediated protein degradation was involved in appressorium formation. Pharmacological analysis using proteasome inhibitors, MG-132, proteasome inhibitor I (PI) and proteasome inhibitor II (PII) revealed that germination and appressorium formation were delayed for 4 to 6 h on rice leaf wax-coated plates. Similarly, the treatment of proteasome inhibitors with fungal conidia on the rice leaf surface delayed appressorium formation and host infection processes as well. Additionally, fungal pathogenicity was strongly reduced at 4 days' postfungal infection. These data indicated that the fungal 20S proteasome might be involved in the pathogenicity of M. oryzae by the suppression of germination and appressorium formation.

• 생약학회지
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• 제39권4호
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• pp.365-368
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• 2008

Recently proteasome inhibitors have been emerged as potential anticancer agents. In a continuous study on exploring proteasome inhibitors from natural products, fruiting body of Hericium erinaceum was investigated. The MeOH extracts of the fruiting body of Hericium erinaceum was fractionated with several solvents and the fractions were evaluated on the activity to screen the proteasome inhibitors. The n-Hexane and CHCl3 frs. showed potent activity, of which chemical investigations led to ergosterol peroxide (1), hericenones C (2) and D (3). Their structures were determined by spectroscopic methods such as $^1H$-NMR, $^{13}C$-NMR, and FABMS spectra.

• International Journal of Oral Biology
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• 제33권1호
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• pp.25-31
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• 2008

Inhibition of proteasome activity may reduce many types of cancer, so it's pathway is effective in cancer as well as in clinical fields. Here the author has carried out experiment targeting on the elevation of apoptosis in oral cancer cells by combination of proteasome inhibitor, lactacystin, and DNA replication inhibitor, etoposide. The growth of KB cells was measured by MTT methods and apoptosis was analyzed by DNA fragmentation and Hochest nucleus staining. The proteasome activity was analyzed by fluorescent tagged peptide and cellular protein expression was detected by Western hybridization. Though lactacystin and etoposide inhibited KB cell growth alone, but low combined doses inhibited cell growth more strongly and induced apoptosis. The proteasome activity was also seriously inhibited by the combination of both chemicals. Tumor suppressor proteins and apoptosis inducing proteins were highly increased under the combination of both chemicals. From above studies we can conclude that proteasome inhibitors may be used for the treatment of oral cancer and proteasome inhibitors with DNA replication inhibitors may be effective in clinical trials of oral cancer.

• Journal of Microbiology and Biotechnology
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• 제18권10호
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• pp.1655-1658
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• 2008

Cyanobacteria, blue-green algae, are a rich source of bioactive secondary metabolites with many potential applications. The ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. Cancer cells are more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Thus, proteasome inhibitors can be potential anticancer agents. Cyanobacteria have been shown to be a rich source of highly effective inhibitors of proteases. A proteasome inhibitor was screened from an extract of the culture of Scytonema hofmanni on the basis of its inhibitory activity, which led to the isolation of nostodione A with an $IC_{50}$ value of 50${\mu}M$. Its structure was determined by spectroscopic methods such as $^{1}H$-NMR and ESI-MS spectral analyses.

• BMB Reports
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• 제45권5호
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• pp.299-304
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• 2012

The ubiquitin-proteasome system is a major proteolytic system for nonlysosomal degradation of cellular proteins. Here, we investigated the response of mouse embryonic stem (ES) cells under proteotoxic stress. Proteasome inhibitors induced expression of heat shock protein 70 (HSP70) in a concentration- and time-dependent manner, and also induced apoptosis of ES cells. Importantly, more apoptotic cells were observed in ES cells compared with other somatic cells. To understand this phenomenon, we further investigated the expression of HSP70 and pluripotent cell markers. HSP70 expression was more significantly increased in somatic cells than in ES cells, and expression levels of pluripotent cell markers such as Oct4 and Nanog were decreased in ES cells. These results suggest that higher sensitivity of ES cells to proteotoxic stress may be related with lower capacity of HSP70 expression and decreased pluripotent cell marker expression, which is essential for the survival of ES cells.

• 생약학회지
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• 제39권1호
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• pp.56-59
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• 2008

Ubiquitin-proteasome proteolytic system plays an important role in selective protein degradation and regulates cellular events including apoptosis. Cancer cells have been shown to be more sensitive to the proapoptotic effects of proteasome inhibition than normal cells. Thus, proteasome inhibitor can be potential anticancer agent. Since the MeOH extracts of psoraleae semen and processed psoraleae semen showed potent proteasome inhibition activity, the fractions of the extracts were evaluated on the activity to screen the proteasome inhibitors. The $CHCl_3$ fr. of the processed psoraleae semen showed the most potent activity, of which chemical investigation led to two coumarins, psoralen and isopsoralen. Their structures were determined by spectroscopic methods such as $^1H-NMR$ and EIMS spectra.

• 한국식품과학회지
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• 제51권4호
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• pp.393-397
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• 2019

Persimmon leaf extract (PSE) 는 HepG2 인간 간암 세포에서 proteasome의 활성과 $NF-{\kappa}B$ 활성화를 억제하였고 cell cycle에서 G2/M기와 sub-G1기의 cell population을 유의하게 증가시켰다. 이러한 결과는 PSE의 식물생리활성물질을 proteasome 활성 억제제로 개발할 수 있는 가능성을 제시한다.

• Journal of Oral Medicine and Pain
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• 제34권3호
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• pp.261-276
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• 2009

Sreptomyces라는 세균에서 추출한 lactacystin은 선택적인 proteasome 억제제로서 많은 연구에서 사용되어져 왔다. Proteasome 억제제는 최근의 많은 연구를 통해서 암세포증식의 억제에 대한 효과가 증명되었으며, 특히 다른 항암제와 병용처리 시, 상호작용에 의한 상승효과가 있다고 알려져 있다. 현재 proteasome 억제제는 새로운 강력한 항암제로서 분류되어 있다. 본 연구는 사람혀편평세포암종세포(SCC25 cells)에서 lactacystin의 세포독성과 성장억제 효과, 그리고 세포자멸사의 유도에 대한 분자생물학적 기전을 밝히기 위해 실험을 시행하였다. SCC25 세포, 사람정상각화세포 (HaCaT cells) 그리고 사람치은섬유모세포(HGF-1 cells)의 생존율 측정은 MTT법을 시행하였고, SCC25 세포의 성장억제를 확인하기 위해서는 clonogenic assay를 사용하였다. lactcystin이 SCC25 세포에서 세포자멸사가 유도되는지를 확인하기 위해서 hoechst 염색법, hemacolor 염색법 그리고 TUNEL법을 시행하였다. 그리고 SCC25 세포에 lactacystin을 적용한 후, Western blot 분석, 세포면역화학염색, 공초점레이저주사현미경 검경, FACScan flow cytometry, 사립체막 전위변화, proteasome 활성도 측정 등을 시행하였다. Lactacystin으로 처리된 SCC25 세포는 시간 및 용량 의존적인 세포생존율의 감소, 용량의존적인 세포성장억제 그리고 세포자멸사에 의한 세포죽음을 보였다. 흥미롭게도 lactacytin은 정상세포인 HaCat 세포와 HGF-1 세포에서는 세포독성을 전혀 보이지 않았다. 그리고 lactacystin이 적용된 SCC25세포에서 핵 응축, DNA의 조각남, 사립체막전위와 proteasome 활성도의 감소, DNA 양의 감소, cytochrome c의 사립체에서의 세포질로의 유리, AIF와 DFF40 (CAD)의 핵으로의 이동, Bax의 증가, caspase-7, caspase-3, PARP, lamin A/C 그리고 DFF45 (ICAD)의 활성화 혹은 파괴와 같은 아주 다양한 세포자멸사 증거를 보였다. Flow cytometry 분석에서는 CDK 억제제인 $p21^{WAF1/CIP1}$와 $p27^{KIP1}$의 발현 증가와 관계있는 것으로 추정되어 지는 G1 세포주기 정지를 보였다. 이러한 결과는 lactacytin이 SCC25 세포에서 G1 세포주기정지와 proteasome, 사립체 및 caspase 경로의 연속반응을 통한 세포자멸사를 유도함을 명확하게 증명하고 있다. 이와 같은 세포주기 정지와 세포자멸사 유도능은 lactacytin이 사람혀편평상피세포암종의 새로운 치료전략으로서의 가능성을 제공한다고 생각한다.

• 대한의생명과학회지
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• 제10권3호
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• pp.179-186
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• 2004

We examined a role of proteasome, the non-lysosomal multicatalytic protease complex,on the differentiation of chick embryonic myoblasts in culture. The peptide hydrolyzing activities of proteasome were found to change; the hydrolyzing activity against N-succinyl-Leu-Leu- Val- Tyr-7 -amido-4-methy1coumarin (SLLVY-AMC) was prominent and increased with myogenic differentiation. Proteasome inhibitors, N-carbobenzoxy-Leu-Leu-norvalinal (MG115) and N-carbobenzoxy-Ile-Glu (O-t-butyl)-Ala-Leucinal (PSI), blocked membrane fusion of myoblasts as well as the SLLVY-AMC hydrolyzing activity. Those inhibitory activities of the agents occurred in parallel, but were reversible and both cell fusion and the peptidase activity were restored when the agents were withdrawn from the culture medium. On the other hand, the agents caused accumulation of the ubiquitinylated proteins in the cytoskeletal proteins. These results suggest that each of the peptide hydrolyzing activities of proteasome is independently regulated during the myogenic differentiation and the chymotrypsin-like activity may play an important role in that process.