• Journal of Applied Biological Chemistry
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• 제63권3호
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• pp.235-241
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• 2020

An essential component of the hemostatic process during vascular damage is platelet activation. However, many cardiovascular diseases, such as atherosclerosis, thrombosis, and myocardial infarction, can develop due to excessive platelet activation. Isoscopoletin, found primarily in plant roots of the genus Artemisia or Scopolia, has been studied to demonstrate potential pharmacological effects on Alzheimer's disease and anticancer, but its mechanisms and role in relation to thrombus formation and platelet aggregation have not yet been discovered. This research investigated the effect of isoscopoletin on collagen-induced human platelet activation. As a result, isoscopoletin strongly increased cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) levels in a concentration-dependent manner. In addition, isoscopoletin greatly phosphorylated inositol 1,4,5-triphosphate receptor (IP₃R) and vasodilator-stimulated phosphoprotein (VASP), known substrates of cAMP-dependent kinase and cGMP dependent kinase. Phosphorylation of IP₃R by isoscopoletin induced Ca²⁺ inhibition from the dense tubular system Ca²⁺ channels, and VASP phosphorylation was involved in fibrinogen binding inhibition by inactivating αIIb/β₃ in the platelet membrane. Isoscopoletin finally reduced thrombin-induced fibrin clot production and finally reduced thrombus formation. Therefore, this research suggests that isoscopoletin has strong antiplatelet effects and is likely to be helpful for thrombotic diseases involving platelets by acting as a prophylactic and therapeutic agent.

• 생약학회지
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• 제52권1호
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• pp.26-33
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• 2021

During blood vessel damage, an essential step in the hemostatic process is platelet activation. However, it is important to properly control platelet activation, as various cardiovascular diseases, such as stroke, atherosclerosis, and myocardial infarction, are also caused by excessive platelet activation. Found primarily in the roots of plants of the genus Artemisia or Scopolia, isoscopoletin has been studied to demonstrate its potential pharmacological effects against Alzheimer's disease and anticancer, but the mechanisms and roles involved in thrombus formation and platelet aggregation are insufficient. This study investigated the effect of isoscopoletin on U46619-induced human platelet activation. As a result, isoscopoletin significantly increased the levels of cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) dose-dependently. In addition, isoscopoletin significantly phosphorylated inositol 1, 4, 5-triphosphate receptor (IP3R) and vasodilator-stimulated phosphprotein (VASP), which are known substrates for cAMP-dependent kinases and cGMP-dependent kinases. Phosphorylated IP3R by isoscopoletin inhibited Ca2+ mobilization from the dense tubular system Ca2+ channels to cytosol, and phosphorylated VASP was involved in the inhibition of fibrinogen binding through αIIb/β3 inactivation in the platelet membrane. Isoscopoletin finally reduced thrombin-induced fibrin clotting production. Therefore, this study suggests that isoscopoletin has a potent antiplatelet effect and may be helpful for platelet-related thrombotic diseases.

• 식물분류학회지
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• 제51권4호
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• pp.345-352
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• 2021

Diarthron linifolium Turcz. is an annual herb usually found in sandy soil or limestone areas. Plants in the genus Diarthron are known to have toxic chemicals that may, however, be potentially useful as an anticancer treatment. Diarthron linifolium is a unique species among the species of the genus distributed in Korea. Here, we determine the genetic variation of D. linifolium collected in Korea with a full chloroplast genome and investigate its evolutionary status by means of a phylogenetic analysis. The chloroplast genome of Korean D. linifolium has a total length of 172,644 bp with four subregions; 86,158 bp of large single copy and 2,858 bp of small single copy (SSC) regions are separated by 41,814 bp of inverted repeat (IR) regions. We found that the SSC region of D. linifolium is considerably short but that IRs are relatively long in comparison with other chloroplast genomes. Various simple sequence repeats were identified, and our nucleotide diversity analysis suggested potential marker regions near ndhF. The phylogenetic analysis indicated that D. linifolium from Korea is a sister to the group of Daphne species.

• Oncology Letters
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• 제41권1호
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• pp.361-368
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• 2019

Gliomas, the most highly malignant central nervous system tumors, are associated with an extremely poor patient survival rate. Given that gliomas are derived from mutations in glial precursor cells, a considerable number of them strongly react with glial precursor cell-specific markers. Thus, we investigated whether malignant gliomas can be converted to glial cells through the regulation of endogenous gene expression implicated in glial precursor cells. In the present study, we used three small-molecule compounds, [cyclic adenosine monophosphate (cAMP) enhancer, a mammalian target of rapamycin (mTOR) inhibitor, and a bromodomain and extra-terminal motif (BET) inhibitor] for glial reprogramming. Small-molecule-induced gliomas (SMiGs) were not only transformed into exhibiting a glial-specific morphology, but also showed positive reactions with glial-specific markers such as glial fibrillary acidic protein (GFAP), 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP) and anti-oligodendrocyte (RIP). A microarray analysis indicated that SMiGs exhibited a marked increase in specific gene levels, whereas that of a malignant cancer-specific gene was greatly decreased. Moreover, proliferation of the cells was markedly suppressed after the conversion of malignant glioma cells into glial cells. Our findings confirmed that malignant gliomas can be reprogrammed to non-proliferating glial cells, using a combination of small molecules, and their proliferation can be regulated by their differentiation. We suggest that our small-molecule combination (with forskolin, rapamycin and I-BET151) may be the next generation of anticancer agents that act by reprogramming malignant gliomas to differentiate into glial cells.

• Asian Pacific Journal of Cancer Prevention
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• 제16권18호
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• pp.8467-8471
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• 2016

Background: One of the major mechanisms for drug resistance is associated with altered anticancer drug transport, mediated by the human-adenosine triphosphate binding cassette (ABC) transporter superfamily proteins. The overexpression of adenosine triphosphate binding cassette, sub-family B, member 1 (ABCB1) by multidrug-resistant cancer cells is a serious impediment to chemotherapy. In our study we have studied the possibility that structural single-nucleotide polymorphisms (SNP) are the mechanism of ABCB1 overexpression. Materials and Methods: A total of 101 gastric cancer multidrug resistant cases and 100 controls were genotyped with sequence-specific primed PCR (SSP-PCR). Gene expression was evaluated for 70 multidrug resistant cases and 54 controls by real time PCR. The correlation between the two groups was based on secondary structures of RNA predicted by bioinformatics tool. Results: The results of genotyping showed that among 3 studied SNPs, rs28381943 and rs2032586 had significant differences between patient and control groups but there were no differences in the two groups for C3435T. The results of real time PCR showed over-expression of ABCB1 when we compared our data with each of the genotypes in average mode. Prediction of secondary structures in the existence of 2 related SNPs (rs28381943 and rs2032586) showed that the amount of ${\Delta}G$ for original mRNA is higher than the amount of ${\Delta}G$ for the two mentioned SNPs. Conclusions: We have observed that 2 of our studied SNPs (rs283821943 and rs2032586) may elevate the expression of ABCB1 gene, through increase in mRNA stability, while this was not the case for C3435T.

• Molecular & Cellular Toxicology
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• 제3권2호
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• pp.137-144
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• 2007

The mechanism of cytotoxicity of doxifluridine, a prodrug fluorouracil (5-FU), has been ascribed to the misincorporation of fluoropyrimidine into RNA and DNA and to the inhibition of the nucleotide synthetic enzyme thymidylate synthase. Increased understanding of the mechanism of 5-FU has led to the development of strategies that increases its anticancer activity or predicts its sensitivity to patients. Using GeneChip?? Rhesus Macaque Genome arrays, we analyzed gene expression profiles of doxifluridine after two weeks repeated administration in cynomolgus monkey. Kegg pathway analysis suggested that cytoskeletal rearrangement and cell adhesion remodeling were commonly occurred in colon, jejunum, and liver. However, expression of genes encoding extracellular matrix was distinguished colon from others. In colon, COL6A2, COL18A1, ELN, and LAMA5 were over-expressed. In contrast, genes included in same category were down-regulated in jejunum and liver. Interestingly, MMP7 and TIMP1, the key enzymes responsible for ECM regulation, were overexpressed in colon. Several studies were reported that both gene reduced cell sensitivity to chemotherapy-induced apoptosis. Therefore, we suggest they have potential as target for modulation of 5-FU action. In addition, the expression of genes which have been previously known to involve in 5-FU pathway, were examined in three organs. Particularly, there were more remarkable changes in colon than in others. In colon, ECGF1, DYPD, TYMS, DHFR, FPGS, DUT, BCL2, BAX, and BAK1 except CAD were expressed in the direction that was good response to doxifluridine. These results may provide that colon is a prominent target of doxifluridine and transcriptional profiling is useful to find new targets affecting the response to the drug.

• 한국미생물·생명공학회지
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• 제49권3호
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• pp.458-465
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• 2021

Tubulysin은 다양한 암세포주에 대해 강한 항암활성을 보이는 점액세균 유래 이차대사 생리활성물질이다. 본 연구에서는 tubulysin을 생산하는 두 균주의 점액세균 Archangium gephyra MEHO_002와 MEHO_004의 유전체 분석을 통해 tubulysin 생합성 유전자들로 추정되는 유전자군을 발견하였으며, 플라스미드 삽입에 의한 유전자 불활성화를 통해 이들 유전자들이 tubulysin 생산과 직접 연관되어 있음을 확인하였다. A. gephyra MEHO_002와 MEHO_004 균주의 tubulysin 생합성 유전자군(tubA~tubF)은 DNA 염기서열이 서로 97% 동일하였으며, 암호화하는 단백질들의 아미노산 서열도 서로 97-100% 유사하였다. MEHO_002와 MEHO_004 균주의 tubulysin 생합성 유전자군은 tubulysin 생산 점액세균으로 알려진 Cystobacter sp. SBCb004의 tubulysin 생합성 유전자군과 DNA 염기서열이 86% 동일하였다. 유전자군의 구성은 tubZ 유전자가 존재하지 않는다는 점을 제외하고는 SBCb004의 tubulysin 생합성 유전자군 구성과 동일하였다. 각 유전자가 암호화하는 단백질의 아미노산 서열은 Cystobacter sp. SBCb004의 tubulysin 생합성 유전자가 암호화하는 단백질들과 88-97% 유사하였으며, 각 단백질들의 도메인 구성도 동일하였다.

• Journal of Applied Biological Chemistry
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• 제66권
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• pp.402-407
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• 2023

혈소판 응집의 조절은 정상적인 지혈을 유지하는 데 중요하지만 비정상적이거나 과도한 혈소판 응집은 뇌졸중, 죽상동맥 경화증 및 혈전증과 같은 심혈관 질환에 기여할 수 있다. 따라서 혈소판 응집을 제어하거나 억제할 수 있는 물질을 식별하는 것은 이러한 상태의 예방 및 치료를 위한 유망한 접근 방식이다. Artemisia 또는 Scopolia 속 식물에서 추출한 artemisinin은 항암 및 알츠하이머병 연구와 같은 다양한 분야에서 가능성을 보여주었다. 그러나 artemisinin이 혈소판 활성화 및 혈전 형성에 영향을 미치는 구체적인 역할과 메커니즘은 아직 완전히 밝혀지지 않았다. 이 연구는 혈소판 활성화 및 혈전 형성에 대한 artemisinin의 효과를 조사하였다. 그 결과, cAMP 생성과 cAMP 의존성 kinase에 대한 기질인 VASP 및 IP₃R의 인산화가 artemisinin에 의해 유의미하게 증가되었다. IP₃R의 인산화는 조밀한 관형 시스템에서 정상적으로 동원되는 Ca²⁺를 억제하였고, VASP의 인산화는 αIIb/β₃ 혈소판 막 불활성화를 통한 fibrinogen 결합을 억제하였다. 마지막으로, artemisinin은 thrombin이 유발하는 혈전 형성을 농도의존적으로 억제하였다. 따라서 우리는 artemisinin이 혈소판 활성화의 효과적인 예방 및 치료제로 작용하여 비정상적인 혈소판 응집 및 혈전 형성으로 인해 유발되는 심혈관 질환의 개선에 기여할 수 있음을 제안한다.