• 한국미생물·생명공학회지
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• 제21권1호
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• pp.47-53
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• 1993

순수분리된 2,000여주의 혐기성 세균으로부터 선발된 Clostridium sp. KN-431은 bacteria 및 fungi에 대하여 재현성있는 항균활성을 나타내는 항생물질 KG-431A와 KG-431B를 생산하였다. 이들 중 KG-431B는 항암활성이 1차 검색에서도 양성반응을 보인 바 이에 대한 후속연구를 계획중에 있다. 이들의 MIC 값을 비교해 보면 완전정제가 가능하였던 KG-431B 보다는 차라리 정제과정에서 많은 어려움이 따라 불완전 상태로 실험을 행한 KG-431A의 활성이 더 뛰어난 것을 알 수 있었다. 정제된 KG-431B의 여러가니 이화학적 특성과 spectra datark 기지물질인 3-IPA와 일치하나 본 실험을 통해 밝혀진 항암활성의 검색은 정제된 3-IPA에서는 아직까지 알려진 바 없는 생물학적 특성으로 간주된다. 또한 Clostridium 속에서 최초로 발견된 3-IPA 존재에 대한 결과는 아직 정제가 완료되지 않은 KG-431B에 관한 연구와 함께 후속적인 확인 연구가 진행중에 있다.

• 한국미생물·생명공학회지
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• 제21권1호
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• pp.41-46
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• 1993

순수분리된 2,000여 주의 혐기성 세균으로부터 선발된 stain KH-431은 bacteria 및 fungi에 대하여 재현성있는 항균활성을 보이는 물질을 생산하였다. Strain KH-431은 그 형태 및 생리, 생화학적 특성으로 미루어 보아 Clostridium fallax의 근연종으로 동정되었다. strain KH-431의 항생물질 생산을 위한 최적 배양조건에 대해 고찰한 결과 PY배지를 기초배지로 사용하고 sorbitol, yeast extract, d-biotin 그리고 $CaCl_2$를 영양원으로 첨가하였을 때가 양호한 것으로 나타났다. 배지초기 pH 및 배양온도 배양시간에 대한 최적조건은 각각 pH7과 $30^{\circ}C$, 108시간으로 나타났다.20$\ell$ 의 배양액으로부터 solvent extraction, silica gel column chromatography를 거쳐 얻은 sample을 재결정한 결과 KG-431B는 순수한 결정상태로 얻어졌으나 KG-431A의 완전정제에는 많은 문제점이 뒤따른 바 현재 다른 정제방법의 도입을 고려중에 있다.

• BMB Reports
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• 제34권3호
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• pp.189-193
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• 2001

Curcumin a yellow pigment from Curcuma Tonga, has been known to possess antioxidative and anticarcinogenic properties, as well as to induce apoptosis in some cancer cells. There have been, however, several contradictory reports that hypothesized curcumin (a hydrophobic molecule) can bind a membrane Gpid bilayer and induce nonspecific cytotoxicity in some cell lines. Why curcumin shows these contradictory effects is unknown. In A-431 cells, growth inhibition by curcumin is due mostly to the specific inhibition of the intrinsic tyrosine kinase activity of the epidermal growth factor receptor, as reported earlier by Korutla et al. Thus, we assumed that the cell death of A-431 by curcumin might be due to the specific induction of apoptosis. In this paper we clearly show that curcumin induces apoptosis in A-431 cells. The cureumin-induced cell death of A-431 exhibited various apoptotic features, including DNA fragmentation and nuclear condensation. Furthermore, the curcumin-induced apoptosis of A-431 cells involved activation of caspase-3-like cysteine protease. Involvement of caspase-3 was further confirmed by using a caspase-3 specific inhibitor, DEVD-CHO. In another study, decreased nitric oxide (NO) production was also shown in A-431 cells treated with curcumin, which seems to be the result of the inhibition of the iNOS expression by curcumin, as in other cell lines. However, 24 h after treatment of curcumin there was increased NO production in A-431 cells. This observation has not yet been clearly explained. We assumed that the increased NO production may be related to denitrosylation of the enzyme catalytic site in caspase-3 when activated. Taken together, this study shows that the cell death of A-431 by curcumin is due to the induction of apoptosis, which involves caspase-3 activation.

• 치과방사선
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• 제29권1호
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• pp.327-339
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• 1999

Objectives: The purpose of this study was to aid in the prediction of tumor cell tolerance to radiotherapy and/or chemotherapy. Material and Methods: Human epidermoid carcinoma A-431 cell lines were irradiated by 2, 4, 6, 8, 10Gy at a dose rate of 210cGy/min using /sup 60/Co Irradiator ALDORADO 8 and then were exposed to bleomycin or cisplatin at concentration of 2㎍/㎖ for 1 hour. The viable cells were determined for each radiation dose and/or each drug at the 4th day and cell surviving curves were obtained using semiautomated MTT assay. Results: The surviving fraction after irradiation of 2Gy was 0.99, and there was not significant difference of surviving fraction in comparison with the control group on A-431 cell line(P>0.05). But there were significant differences of surviving fractions at doses of 4, 6, 8, 10Gy in comparison with the control group(P<0.05). The cytotoxicity of bleomycin or cisplatin was significantly different in comparison with the control group on A-43l cell line (P<0.05). And the cytotoxicity of cisplatin was greater than that of bleomycin on A-431 cell line (P<0.05). There were significant differences of surviving fractions after irradiation of 2, 4, 6, 8, 10Gy with bleomycin or cisplatin in comparison with each group of irradiation only on A-431 cellline(P<0.05). There were significant differences of surviving fractions between the groups of irradiation with bleomycin and cisplatin at doses of 2, 4Gy(P<0.05), but there were not significant differences of surviving fractions at doses of 6, 8, 10Gy on A-431 cell line (P>0.05).

• BMB Reports
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• 제31권3호
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• pp.245-248
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• 1998

Human epidermoid carcinoma A431 cells have an extraordinarily large number of epidermal growth factor (EGF) receptors, and their growth is inhibited by EGF, which results in growth arrest at the Gl phase. In order to investigate the EGF-mediated inhibition mechanism, the expression level of DNA topoisomerase (topo) II was analyzed after EGF treatment. As a result, it was shown that EGF treatment lowered the amount of 170 kDa topo II (topo $II{\alpha}$) but not 180 kDa (topo $II{\beta}$). However, the A431 cell variant resistant to EGF was not sensitive to EGF treatment. These results suggest that EGF-induced growth arrest of A431 cells may be closely related to the depletion of topo $II{\alpha}$.

• 한방안이비인후피부과학회지
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• 제9권1호
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• pp.1-15
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• 1996

The purpose of this research was to investigate effect of water extract of DangKwi-Eum-Ja ka Sumsoo(DESE) on the cytotoxicity of human epidemloid cell, A431 cells. The effects of DESE on the proliferation of A431 cells, Balb/c 3T3 cells, mouse thymocytes and splenocnes were estimated by MTT colorimetric assay, and nitric oxide production from mouse peritoneal macrophage was estimated by Griess method. DESE inhibited the proliferation of A431 cells at $10{\mu}g/ml$, and did not affect the proliferation of Balb/c 3T3 cells. DESE decreased the cytotoxicity of mitomycin C or cisplatin on A431 cells, increased the cytotoxicity of mitomycin C or cisplatin on Balb/c 3T3 cells. DESE inhibited the proliferation of mouse thymocytes and splenocytes at $100{\mu}g/ml$. DESE did not affect the nitric oxide production from mouse peritoneal macrophage in vitro, but decreased the nitric oxide production from DESE-treated mouse peritoneal macrophage.

• BMB Reports
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• 제48권11호
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• pp.595-596
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• 2015

Skeletal muscle exhibits a loss of muscle mass and function with age. Decreased regenerative potential of muscle stem/progenitor cells is a major underlying cause of sarcopenia. We analyzed microRNAs (miRNA) that are differentially expressed in young and old myoblasts, to identify novel intrinsic factors that play a degenerative role in aged skeletal muscle. miR-431, one of decreasing miRNAs in old myoblasts, improved the myogenic differentiation when overexpressed in old myoblast, but suppressed their myogenic capability in knockdowned young myoblasts. We found that miR-431 directly binds to 3` untranslated regions (UTR) of Smad4 mRNA, and decreases its expression. Given that SMAD4 is one of the downstream effectors of TGF-β, a well-known degenerative signaling pathway in myogenesis, the decreased miR-431 in old myoblast causes SMAD4 elevation, thus resulting in defective myogenesis. Exogenous expression of miR-431 greatly improved the muscle regeneration in the cardiotoxin-injured hindlimb muscle of old mice by reducing SMAD4 levels. Since the miR-431 seed sequence is conserved in human SMAD4 3'UTR, miR-431 regulates the myogenic capacity of human skeletal myoblasts in the same manner. Our results suggest that age-associated miR-431 is required for the maintenance of the myogenic capability in myoblasts, thus underscoring its potential as a therapeutic target to slow down muscle aging.

• Asian Pacific Journal of Cancer Prevention
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• 제16권7호
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• pp.2813-2818
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• 2015

Objective: To investigate the regulatory effect of curcumin on expression of signal transducer and activator of transcription 3 (STAT3) in skin squamous cell carcinoma tissues as well as possible mechanisms of curcumin in prevention and treatment of skin squamous cell carcinoma. Materials and Methods: Highly invasive A431 cells were treated with curcumin at various doses .The cytotoxic effects of treatment with 5, 10, 15, 20, 25, 30, 35, 40 and 50 umol/L curcumin for 24, 48 and 72 hours on A431 cells were measured by MTT assay. The invasion capacity of cells treated with 5, 10 and 15 umol/L curcumin was measured by Transwell test, while adhesive ability was assessed by cell adhesion assay. The effects of 5,10 and 15 umol/L curcumin on expression levels of STAT3 were determined by Western blotting and on transcription levels of STAT3 mRNA by RT-PCR. Results: Treatment with curcumin at a doses of more than 15 umol/L for more than 24 hour inhibited the growth of A431 cells in a time-and dose-dependent fashion (p<0.001). The doses of 15 umol/L and less for 24 hours showed no significant cytotoxic effects on the cells, survival rates being more than 85%.The invasion and adhesive abilities decreased gradually with the increasing curcumin concentration, 15 umol/L exerting the strongest inhibitory effects (p<0.05). Curcumin showed significant dose-dependent inhibitory effects on the transcription level of STAT3 mRNA (p<0.05). Conclusions: Curcumin may reduce the invasive ability of A431 cells by inhibiting the activation of STAT3 signal pathway and expression of STAT3 as a target gene in the pathway.

• 미생물학회지
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• 제36권4호
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• pp.312-315
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• 2000

논꽃동충하초(Paecilomyces tenuipes DGUM 32001)의 자실체를 메탄올로 추출하여 인간 암세포주에 대한 세포독성을 조사하였다. 메탄올 추출물의 암세포주에 대한 세포독성은 매우 우수하였다. 메탄올 추출물의 용매 분획 중, 에틸아세테이트 분획에서 가장 우수한 세포독성을 나타내었으며, HeLa, HeLa S3 및 A-431 암세포주에 대한 $IC_{50}$ 값은 각각 13, 35 및 30 $\mu$ g/ml이었다. 그러나, 이 분획의 HeLa 암세포주에 대한 세포독성은 apoptosis에 의하지 않음을 알 수 있었다. 배양 균사체의 메탄올 추출물은 A-431 암세포주에 대해 우수한 세포독성을 보여주었다.

• 생약학회지
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• 제53권4호
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• pp.181-191
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• 2022

As the incidence of skin cancer increases every year, non-surgical treatment methods for cancer are being sought. Esculetin, a natural dihydroxy coumarin, is attracting attention as a therapeutic agent for certain diseases, such as cancer, based on its broad pharmacological activity. In this study, the anticancer ability of esculetin was evaluated using the epidermoid carcinoma cell line A431. As a result of evaluating the apoptosis ability of esculetin by MTT assay, apoptosis was observed in a time-concentration-dependent manner regardless of the presence or absence of FBS. As a result of quantitative real-time PCR, esculetin reduced cyclin D1 mRNA in a time-concentration-dependent manner. In addition, as a result of western blotting, esculetin significantly inhibited phosphorylation of ERK, JNK, and p38 in a concentration-dependent manner. The results of this study suggest that esculetin has the potential to be used as an effective natural medicine for the treatment of skin cancer.