• 고려인삼학회:학술대회논문집
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• 고려인삼학회 1993년도 학술대회지
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• pp.127-131
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• 1993

The effects of total ginseng saponin. extracts of Panax ginseng C.A. Meyer, on the differentiation of F9 teratocarcinoma stem cells were studied. F9 stem cells cultured in the presence of ginseng saponin together with dibutyric cAMP became parietal endoderm - like cells. Moreover, the expressions of differentiation marker genes. laminin. type IV collagen. and retinoic acid $receptor-{\beta}(RAR{\beta})$ were increased after treatment of ginseng saponin. Among various ginsenosides purified from crude ginseng saponin, $Rh_1\;and\;Rh_2$ caused the differentiation of F9 cells most effectively. Since ginsenosides and steroid hormone show resemblance in chemical structure. we studied the possibility of the involvement of a steroid receptor in the differentiation process induced by ginsenosides. According to Southwestern blot analysis, a 94 kDa protein regarding as a steroid receptor was detected in F9 cells cultured in the medium containing ginseng saponin. Based on these data, we suggest that ginseng saponin, especially ginsenosides $Rh_1\;and\;Rh_2$ cause the differentiation of F9 cells and the effects of ginsenosides might be exerted via binding with a steroid receptor or its analogous nuclear receptor.

• 생명과학회지
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• 제8권1호
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• pp.51-59
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• 1998

Ursolic acid(UA)의 apoptosis 유도능을 F9 생쥐 기형암종세포를 대상으로 조사하였다. UA는 피부암화의 억제, tumor의 분화유도, tumor promotion의 억제 등의 항암 효과를 나타내는 pentacyclic triterpene acid로 물질로 알려져 있다. UA를 F9세포에 처리하였을 때 농도비례로 성장억제를 나타냈다. 또한 apoptosis과정에서 관찰되는 전형적인 DNA 분절을 관찰할 수 있었고, 전자현미경을 이용한 세포의 미세구조를 관찰한 결과, 역시 apoptosis과정에서 관찰되는 전형적인 형태인 염색질 응축, 핵의 분절들을 관찰할 수 있어, UA에 의한 항암 효과는 apoptosis에 의한 것임을 시사한다. UA에 의한 apoptosis는 단백질 합성저해제인 cycloheximide에 의해 저해됨을 관찰할 수 있었다. UA를 F4쎄포에 처리한 후 oncogene의 발현양상을 조사한 결과, c-myc과 laminin B1은 apoptosis과정동안 점점 감소하고 c-jun은 증가함을 관찰할 수 있었다. 이상의 결과로서 UA에 의한 F9 세포의 apoptosis에는 새로운 단백질의 합성이 요구되며, c-myc 및 laminin의 발현 감소와 c-jumd의 발현 증가가 관여하고 있음을 시사한다.

• 대한의생명과학회지
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• 제17권1호
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• pp.1-5
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• 2011

Previously, we have identified 14 putative downstream target genes of Hoxc8 homeoprotein in F9 murine embryonic teratocarcinoma cells through proteomics analysis. Among those, we tested a possibility of a DNA-k type molecular chaperone, Grp78, as a direct downstream target of Hoxc8, by cloning a 2.4 kb upstream region of murine Grp78 into a reporter plasmid and by testing if Hoxc8 can regulate its expression. We observed that Hoxc8 proteins could transactivate the reporter gene, which was affected by small interference RNAs (siRNAs) against to Hoxc8, suggesting that Grp78 is a novel downstream target of Hoxc8 in vivo.

• 한국동물학회지
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• 제37권1호
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• pp.40-48
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• 1994

세포분화에 따른 Small GTP-binding protein의 역할을 밝히기 위하여 Retinoic acid(RA)와 dibutyryl cyclic AMP(dbcAMP)로 분화를 유도한 F9 기형암종세포의 형태적인 변화와 함께 Small GTP-binding protein의 분포를 조사하였다. RA와 dbcAMP를 처리한 세포는 분화유도 5일경(초기 분화 단계)에 분명한 세포의 경계를 보이기 시작하여 7일경(분화 후기 단계)에는 거의 모든 세포가 등근 분화된 형태로 전환되었다. 이 분화과정 동안 세포막에는 많은 microvilli와 lamellopodia 같은 구조물이 나타났다. 아울러 초기 분화 단계에 많은 량의 laminin이 발현되었으며 분화 후기에 microtubule의 재분포가 관찰되었다. 세종류의 Small GTP-binding protein(25 23, 21 KD)이 F9 세포의 막성분과 세포질에서 관찰되었으며 분화가 진행됨에 따라서 세단백질 모두 증가되는 양상을 보였다 이러한 결과는 Small GTP-binding protein이 F9 세포의 분화에 특별한 기능을 가지고 있음을 시사해 주고 있다.

• 대한수의학회지
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• 제43권2호
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• pp.211-218
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• 2003

Human ovarian cancerous cells survive in a way that they trigger the nucleotide excision repair (NER) or double-strand DNA repair (dsDNA) repair mechanism to show resistance to anticancer drugs and activate many kinds of repair protein, thus removing damaged DNAs. Two experiments on the PA-1 human ovarian teratocareinoma cell line that hardly has any expression of epidermal growth factor receptor (EGFR) were conducted in the study; first, EGF-R was transfected and its receptor was obtained. The receptor was investigated in terms of its mutual relations with many kinds of protein concerning NER or dsDNA repair. Second, it was examined what kind impact cisplatin and adriamycin had on the effects of EGF-R over the PA-1 cell line lacking EGF-R. When being administered with cisplatin and adriamycin, Hey and Hey C2 cell lines showed a high level of resistance while PA-1 cell line a high level of sensitivity. Hey and Hey C2 cell lines that are resistant against anticancer drugs exhibited a high level of EGF-R expression while PA-1 cell line that is sensitive to them did a much lower level of the expression. When PA-1 cell line was transfected for the expression of DNA adduct and EGF-R, it showed a higher level of resistance compared to the control group. There was no difference in the expression of DNA repair proteins (DNA- dependent protein kinase, Ku70, and Ku80) between Hey and the PA-1 cell lines. The results indicate that the Hey cell line that is resistant against cisplatin and adriamycin works along the signaling system responding to the changes of EGF-R while the PA-1 cell line that is sensitive to both of them does to the lack of EGF-R.

• Molecules and Cells
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• 제24권3호
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• pp.431-436
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• 2007

Stem cell-based therapy is being considered as an alternative treatment for cardiomyopathy. Hence understanding the basic molecular mechanisms of cardiomyocyte differentiation is important. Besides BMP or Wnt family proteins, $TGF-{\beta}$ family members are thought to play a role in cardiac development and differentiation. Although $TGF-{\beta}$ has been reported to induce cardiac differentiation in embryonic stem cells, the differential role of $TGF-{\beta}$ isoforms has not been elucidated. In this study, employing the DMSO-induced cardiomyocyte differentiation system using P19CL6 mouse embryonic teratocarcinoma stem cells, we investigated the $TGF-{\beta}$-induced signaling pathway in cardiomyocyte differentiation. $TGF-{\beta}1$, but not the other two isoforms of $TGF-{\beta}$, was induced at the mRNA and protein level at an early stage of differentiation, and Smad2 phosphorylation increased in parallel with $TGF-{\beta}1$ induction. Inhibition of $TGF-{\beta}1$ activity with $TGF-{\beta}1$-specific neutralizing antibody reduced cell cycle arrest as well as expression of the CDK inhibitor $p21^{WAF1}$. The antibody also inhibited induction of the cardiac transcription factor Nkx2.5. Taken together, these results suggest that $TGF-{\beta}1$ is involved in cardiomyocyte differentiation by regulating cell cycle progression and cardiac gene expression in an autocrine or paracrine manner.

• 대한의생명과학회지
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• 제13권3호
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• pp.239-244
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• 2007

Hoxc8 is one of the homeotic developmental control genes regulating the expression of many downstream target genes, through which animal body pattern is established during embryonic development. In previous proteomics analysis, proliferating cell nuclear antigen (PCNA) which is also known as cyclin, has been implied to be regulated by Hoxc8 in F9 murine embryonic teratocarcinoma cell. When the 5' upstream region of PCNA was analyzed, it turned out to contain 20 Hox core binding sites (ATTA) in about 1.17 kbp (kilo base pairs) region ($-520{\sim}-1690$). In order to test whether this region is responsible for Hoxc8 regulation, the upstream 2.3 kbp fragment of PCNA was amplified through PCR and then cloned into the pGL3 basic vector containing a luciferase gene as a reporter. When the luciferase activity was measured in the presence of effector plasmid (pcDNA : c8) expressing murine Hoxc8, the PCNA promoter driven reporter activity was reduced. To confirm whether this reduction is due to the Hoxc8 protein, the siRNA against Hoxc8 (5'-GUA UCA GAC CUU GGA ACU A-3' and 5'-UAG UUC CAA GGU CUG AUA C-3') was prepared. Interestingly enough, siRNA treatment up regulated the luciferase activity which was down regulated by Hoxc8, indicating that Hoxc8 indeed regulates the expression of PCNA, in particular, down regulation in NIN3T3 cells. These results altogether indicate that Hoxc8 might orchestrate the pattern formation by regulating PCNA which is one of the important proteins involved in several processes such as DNA replication and methylation, chromatin remodeling, cell cycle regulation, differentiation, as well as programmed cell death.

• Journal of Microbiology and Biotechnology
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• 제34권7호
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• pp.1452-1463
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• 2024

Fungi generate different metabolites some of which are intrinsically bioactive and could therefore serve as templates for drug development. In the current study, six endophytic fungi namely Aspergillus flavus, Aspergillus tubigenesis, Aspergillus oryzae, Penicillium oxalicum, Aspergillus niger, and Aspergillus brasiliensis were isolated and identified from the medicinal plant, Silybum marianum. These endophytic fungi were identified through intra transcribed sequence (ITS) gene sequencing. The bioactive potentials of fungal extracts were investigated using several bioassays such as antibacterial activity by well-diffusion, MIC, MBC, anti-biofilm, antioxidant, and haemolysis. The Pseudomonas aeruginosa PAO1 was used to determine the antibiofilm activity. The ethyl acetate extract of Aspergillus flavus showed strong to moderate efficacy against Staphylococcus aureus, Escherichia coli, P. aeruginosa, and Bacillus spizizenii. Aspergillus flavus and Aspergillus brasiliensis exhibited significant antibiofilm activity with IC₅₀ at 4.02 and 3.63 mg/ml, while A. flavus exhibited maximum antioxidant activity of 50.8%. Based on HPLC, LC-MS, and NMR experiments kojic acid (1) and carbamic acid (methylene-4, 1-phenylene) bis-dimethyl ester (2) were identified from A. flavus. Kojic acid exhibited DPPH free radical scavenging activity with an IC₅₀ value of 99.3 ㎍/ml and moderate activity against ovarian teratocarcinoma (CH1), colon carcinoma (SW480), and non-small cell lung cancer (A549) cell lines. These findings suggest that endophytic fungi are able to produce promising bioactive compounds which deserve further investigation.

• 생명과학회지
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• 제25권6호
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• pp.703-708
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• 2015

Hox 유전자는 호메오도메인을 포함한 전사인자로써, 발생 과정 중 전후축을 따라 몸의 형태 형성을 조절하는 역할을 한다. 레티노산(RA)은 발생 과정에서 필수적인 형태형성인자이며 세포의 특성을 결정하는데 중요한 조절자이다. 특히, RA는 생쥐나 인간으로부터 만들어진 배아암종(EC)세포에서 Hox 유전자의 발현을 조절한다고 밝혀져 있다. 또한 RA에 의한 세포 분화와 유전자 조절 과정에 히스톤 변이가 중요한 역할을 하는 것으로 보고되어 있다. 히스톤 변이가 RA에 의해 유도되는 Hox 유전자의 발현에 특이적인 역할을 할 것으로 유추되기 때문에, 이 연구의 목적은 F9 생쥐배아 기형암종세포에서 RA에 의해 유도되는 Hoxc 유전자의 순차적인 발현이 히스톤 변이에 의해 일어나는 것인지를 조사하는 것이다. Hox 유전자의 발현 양상과 히스톤 변이는 semi-quantitative RT-PCR, RNA-sequencing과 chromatin immuno-precipitation (ChIP)-PCR 기법을 이용하여 관찰하였다. RA 처리 후(0일(D0), 1일(D1), 3일(D3)), Hoxc4 유전자의 발현(D1)은 Hoxc5부터 –c10 유전자(D3)보다 먼저 시작되었다. Hox가 발현하지 않는 D0 샘플은 전사 억제 마커인 H3K27me3이 모든 Hoxc 좌위에 강하게 표지 되어 있었으나 D1과 D3 샘플에서는 모든 좌위의 H3K27me3 표지가 확연히 줄어들어 있었다. 전사 발현 마커인 H3K4me3가 Hoxc 유전자의 순차적인 발현과 더 연관성이 있는 것으로 보이는데 D1에서 Hoxc4 발현과 함께 H3K4me3이 표지 되어 있었고, D3에서는 Hoxc 유전자 발현과 함께 모든 좌위에서 H3K4me3 마커가 존재했기 때문이다. 모든 결과를 종합해 보았을 때 F9 세포에서 RA에 의해 유도된 Hoxc 유전자의 순차적인 발현은 Hoxc 좌위에서 H3K27me3가 사라지고, H3K4me3가 표지 되는 히스톤 메틸화의 변이에 의해 결정되는 것으로 사료된다.