• BMB Reports
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• 제38권4호
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• pp.474-480
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• 2005

Curcumin, a major active component of turmeric, has been identified as an inhibitor of the transcriptional activity of activator protein-1 (AP-1). Recently, it was also found that curcumin and synthetic curcumin derivatives can inhibit the binding of Jun-Fos, which are the members of the AP-1 family, to DNA. However, the mechanism of this inhibition by curcumin and its derivatives was not disclosed. Since the binding of Jun-Fos dimer to DNA can be modulated by redox control involving conserved cysteine residues, we studied whether curcumin and its derivatives inhibit Jun-Fos DNA binding activity via these residues. However, the inhibitory mechanism of curcumin and its derivatives, unlike that of other Jun-Fos inhibitors, was found to be independent of these conserved cysteine residues. In addition, we investigated whether curcumin derivatives can inhibit AP-1 transcriptional activity in vivo using a luciferase assay. We found that, among the curcumin derivatives examined, only inhibitors shown to inhibit the binding of Jun-Fos to DNA by Electrophoretic Mobility Shift Assay (EMSA) inhibited AP-1 transcriptional activity in vivo. Moreover, RT-PCR revealed that curcumin derivatives, like curcumin, downregulated c-jun mRNA in JB6 cells. These results suggest that the suppression of the formation of DNA-Jun-Fos complex is the main cause of reduced AP-1 transcriptional activity by curcuminoids, and that EMSA is a suitable tool for identifying inhibitors of transcriptional activation.

• BMB Reports
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• 제34권1호
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• pp.28-32
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• 2001

The Fos-Jun heterodimers are part of the regulatory network of gene expression and nuclear proteins encoded by proto-oncogenes. The activation of Fos-Jun is important in the transmission of the tumor-promoting signal from the extracellular environment to the nuclear transcription mechanism. To search for the inhibitors of the Fos-Jun DNA complex formation, several natural products were screened and water-soluble paeoniflorin reduced the binding activity of the Fos-Jun heterodimer. This active compound was purified by silica gel column chromatography and HPLC. The electrophoresis mobility shift assay and reverse-phase HPLC test showed that paeoniflorin reduced the AP-l function. The cytotoxic effect of paeoniflorin was observed in HL-60. These results indicate that paeoniflorin blocks the Fos-Jun heterodimer-binding site of the AP-l DNA and it also has cytotoxic effects on human leukemia cell lines.

• Bulletin of the Korean Chemical Society
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• 제27권4호
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• pp.535-538
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• 2006

In our previous studies, we have observed that curcumin and momordin I isolated from Ampelopsis radix inhibit the formation of Fos-Jun-activation protein-1 (AP-1) DNA complex. We have screened more effective compounds which have a 5-membered ring framework like momordin I and have modified disaccharide or carboxylic acid portions in momordin I. We synthesized momordin I derivatives according to the published method with slight modification. Synthetic momordin I derivatives showed remarkable inhibitory activities on Fos-Jun-AP-1 DNA complex formation results in in vitro assays. The $IC_{50}$ values of momordin I derivatives were about 4.0 $\mu$M in an electrophoretic mobility shift assay (EMSA). This value is about 125 times higher than that of curcumin and about 12 times higher than that for curcumin derivative C1, and moreover about 30 times higher than that for momordin I. We found momordin I derivatives (a) and (b) are the strongest inhibitory compound for Fos-Jun-AP-1 DNA complex formation.

• Bulletin of the Korean Chemical Society
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• 제25권12호
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• pp.1769-1774
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• 2004

Jun/Fos, a crucial factor in transmitting the tumor-promoting signal from the extracellular environment to the nuclear transcription machinery, has a dimerization interface possessing several coiled structural properties. Jun and Fos can interact with the DNA regulatory region, AP-1 (Activator Protein-1), which is composed of 5'-TGAC/GTCA-3'.$^1$ Curcumin is a well-known anticancer and anti-inflammatory compound.$^{2,3}$ It also acts as an inhibitor of the Jun-Fos function. c-Fos and c-Jun with a bZIP region are overexpressed in BL21 E. coli and purified with an $Ni^{2+}$ affinity column. The inhibitors of Fos-Jun-AP-1 complex formation were searched through the EMSA (electrophoresis mobility shift assay) experiment, and new curcuminoids were synthesized and investigated as to their inhibitory effect on the same system. Two curcuminoids showed a stronger inhibitory effect than curcumin. This inhibitory activity was quantified with EMSA. 1,7-bis(4-methyl)-1,6-heptadiene-3,5-dione (BJC003) and 1,7-bis(4-hydroxy-5-methoxy-3-nitrophenyl)-1,6-heptadiene-3,5-dione (BJC005) showed remarkably high inhibitory activities. $IC_{50}$ of 1,7-bis(4-methyl)-1,6-heptadiene-3,5-dione (BJC003) and 1,7-bis(4-hydroxy-5-methoxy-3-nitrophenyl)-1,6-heptadiene-3,5-dione (BJC005) are 8.98 ${\mu}M$ and 5.40 ${\mu}M$, respectively. However, 1,7-bis(4-methyl-3-nitrophenyl)-1,6-heptadiene-3,5-dione (BJC004) did not show inhibitory activity.

• BMB Reports
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• 제32권6호
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• pp.594-598
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• 1999

The Jun and Fos families of eukaryotic transcription factors form heterodimers capable of binding to their cognate DNA enhancer elements. We are interested in searching for inhibitors or antagonists of the binding of the Jun-Fos heterodimer to the activator protein-1 (AP-1) site. The basic-region leucine zipper (bZIP) domain of c-Fos was expressed as a fusion protein with glutathione S-transferase, and allowed to form a heterodimer with the bZIP domain of c-Jun. The heterodimer was bound to glutathione-agarose, to which were added radiolabeled AP-1 nucleotides. After thorough washing, the gel-bound radioactivity was counted. The assay is faster than the coventional electrophoretic mobility shift assay because the gel electrophoresis step and the autoradiography step are eliminated. Moreover, the assay is very sensitive, allowing the detection of picomolar quantities of nucleotides, and is not affected by up to 50% dimethylsulfoxide, a solvent for hydrophobic inhibitors. Curcumin and dihydroguaiaretic acid, recently known inhibitors of Jun-Fos-DNA complex formation, were applied to this Jun-GST-fused Fos system and revealed to decrease the dimer-DNA binding.

• Bulletin of the Korean Chemical Society
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• 제20권8호
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• pp.925-928
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• 1999

The process of transcription is the major point at which gene expression is regulated. The jun and fos families of eukaryotic transcription factor heterodimerize to form complexes capable of binding 5'-TGAGTCA-3'DNA elements (AP-1 binding site). To search for the inhibitors of the jun-fos-DNA complex formation, several natural products extracts were screened and methanol extract of tanshen (the dried roots of Salvia miltiorrhiza Bunge) showed remarkable inhibitory activity. The active compounds of the extracts were purified using re-peated column chromatography and recrystallization. Their structures were identified as tanshinone I and tanshinone IIA. Through the electrophoresis mobility shift assay and cell cytotoxicity test, tanshinone I and tanshinone IIA were identified as inhibitors that suppress not only AP-1 function but also the cell proliferation. Tanshinone I also suppressed the jun-fos-DNA complex formation in TPA-induced NIH 3T3 cells.

• Bulletin of the Korean Chemical Society
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• 제22권10호
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• pp.1131-1135
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• 2001

• 대한골관절종양학회지
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• 제5권3호
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• pp.162-168
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• 1999

c-fos와 c-jun은 암 유전자의 하나이며, 이 유전자의 단백질 산물은 여러 가지의 다른 활성화 단백 (activator protein 1, AP-1)으로 골 종양에서 골세포의 증식과 분화를 조절하는 중요한 역할을 하는 인자 중 하나로 알려져 있다. 본 연구에서는 단클론 항체를 이용하여 포르말린에 고정된 파라핀 포매조직을 이용하여 35례의 사람 골육종에서 c-fos 단백의 발현을 연구하였다. c-fos의 발현은 골 형성 병변에서 주로 발현되며, 저등급의 연골형성 병변에서는 발현이 관찰되지 않았다. 높은 빈도의 c-fos 단백의 발현이 골아성 골육종에서 발현되었으나 (17례 중 13례에서 1등급 내지 2등급으로 발현), 2례의 연골형성 골육종, 1례의 섬유아세포성 골육종, 2례의 방골성 골육종에서는 음성으로 나타났다. 2례의 혈관확장성 골육종에서는 양성으로 c-fos 단백의 발현되었다. 비록 조직학적으로 고등급의 골육종에서 면역조직화학적 염색상 고 빈도의 c-fos 단백의 발현이 관찰되나, 조직학적 등급과, 면역염색상 발현사이에 통계적인 유의성은 관찰되지 않았다. 이상의 결과로 c-fos 단백이 골육종의 발생에 관여할 것으로 추론되며, 저등급의 연골형성 육종에 이 단백의 역할에는 추후 연구가 필요할 것으로 사료된다.

• 대한의생명과학회지
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• 제18권4호
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• pp.369-376
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• 2012

Platycodon grandiflorum is a medicinal herb that is used to treat pulmonary and respiratory allergic disorders. The objective of this study was to investigate the protective effects of ethyl acetate extract of Platycodon grandiflorum (PGEA) against inflammation and to discern the molecular mechanism of PGEA in lipopolysaccharide (LPS)-induced signal pathways in RAW264.7 macrophage cells. PGEA suppressed the generation of nitric oxide (NO) and the expression of inducible NO synthase induced by LPS in RAW264.7 cells, and inhibited the release of pro-inflammatory cytokines induced by LPS in RAW264.7 cells. Western blot analysis showed that PGEA suppressed LPS-induced phosphorylation of p38 and c-Jun N-terminal kinase (JNK) but not extracellular signal-regulated kinase and $I{\kappa}-B{\alpha}$ degradation. Inactivation of JNK and p38 was effectively alleviated by PGEA, which subsequently affected the activation of c-Jun and c-Fos, which are the essential components of the activator protein-1 (AP-1) transcription complex. Taken together, the results indicate PGEA suppress the activation of p38, JNK, and AP-1, thereby inhibiting the generation of NO and pro-inflammatory cytokines, which affect the regulation of inflammation. PGEA may be useful for the treatment of various inflammatory diseases.

• Journal of Ginseng Research
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• 제32권1호
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• pp.39-47
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• 2008

본 실험은 홍삼 혼합물 (KTNG0345)을 이용한 주름 예방 및 개선효과가 있는 건강기능 식품을 개발하기 위한 기초자료로 활용하기 위하여 시료를 경구투여한 무모생쥐의 피부조직 으로부터 MMP-3의 발현양상과 작용 메커니즘을 연구하였다. MMP-3의 발현정도는 농도 의존적으로 현저한 감소를 나타내었으며, 유전자와 단백질 모두에서 동일한 양상을 보였다. PAK는 변화가 없었지만, p38, p-p38 그리고 c-Jun, p-c-Jun 을 통계적으로 유의하게 감소시킴으로써 MMPs의 발현 감소를 가져온 것으로 보인다. 뿐만 아니라 자외선에 의한 $TNF-{\alpha}$의 생성 또는 유입을 억제함으로써 $TNF-{\alpha}$ receptor에 의해 매개되는 신호전달 경로를 둔화시켜 MMPs의 발현을 감소시킨 것으로 보인다. 이렇게 KTNG0345는 복합적인 활성으로 작용하여 주름생성 억제 활성을 보이는 것으로 판단된다.