• Title/Summary/Keyword: First-in-human dose

검색결과 161건 처리시간 0.036초

항암제 Mitomycin C가 배양임파구의 자매염색분체 교환에 미치는 영향 (Effects of Mitomycin C on Sister Chromatid Exchanges in Cultured Human Lympocytes)

  • 황인담;기노석;이정상;김남송;문태일
    • Journal of Preventive Medicine and Public Health
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    • 제19권2호
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    • pp.244-251
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    • 1986
  • 항암제 mitomycin C가 정상인 배양 임파구의 SCE에 미치는 영향을 알아보기 위해 세포분열지수, 자매염색분체빈도, 세포분열주기 변동 및 염색체군별 SCE 빈도를 조사한 결과는 다음과 같이 요약할 수 있다. 1) 세포당 SCE빈도는 항암제 mitomycin C의 최저농도인 $6.25{\pm}{\times}10^{-9}$ M에서는 $13.1{\pm}2.8$이었고, 최고 농도인 $1.00{\times}10^{-7}$에서는 $75.8{\pm}8.2$로써 농도 증가에 따라 대수증가를 보였다. 그리고 세포분열지수는 완만한 감소경향을 나타냈다. 2) 세포분열주기 변동은 항암제 mitomycin C의 농도 $2.50{\times}10^{-8}M$에서 대조군에 비해 유의한 세포분열지연 현상을 보였으며 (p<0.05), $5{\times}10^{-8}M$ 이상에서는 세포분열지연이 매우 유의하게 나타났다(p<0.01). 3) 염색체군별 단위염색체당 SCE빈도는 항암제의 농도 증가에 따라 절대 빈도는 증가되었다 할지라도 A군에서 G군으로 갈수록 감소되어 특정염색체군과 SCE와의 관계는 보이지 않았다.

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Cl--Channel Is Essential for LDL-induced Cell Proliferation via the Activation of Erk1/2 and PI3K/Akt and the Upregulation of Egr-1 in Human Aortic Smooth Muscle Cells

  • Heo, Kyung-Sun;Ryoo, Sung-Woo;Kim, Lila;Nam, Miyoung;Baek, Seung-Tae;Lee, Hyemi;Lee, Ah-Reum;Park, Song-Kyu;Park, Youngwoo;Myung, Chang-Seon;Kim, Dong-Uk;Hoe, Kwang-Lae
    • Molecules and Cells
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    • 제26권5호
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    • pp.468-473
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    • 2008
  • Low-density lipoprotein (LDL) induces cell proliferation in human aortic smooth muscle cells (hAoSMCs), which may be involved in atherogenesis and intimal hyperplasia. Recent studies have demonstrated that $Cl^-$ channels are related to vessel cell proliferation induced by a variety of stimuli. In this study, we investigated a potential role of $Cl^-$ channels in the signaling pathway of LDL effects on hAoSMC proliferation with a focus on the activation of Erk1/2-PI3K/Akt and the subsequent upregulation of Egr-1. $Cl^-$ channel blockers, DIDS, but neither NPPB nor Furosemide, completely abolished the LDL-induced DNA synthesis and cell proliferation. Moreover, DIDS, but not NPPB, significantly decreased LDL-stimulated $Cl^-$ concentration, as judged by flow cytometry analysis using MQAE as a $Cl^-$-detection dye. DIDS pretreatment completely abolished the activation of Erk1/2 and PI3K/Akt in a dose-dependent manner that is the hallmark of LDL activation, as judged by Western blot and proliferation assays. Moreover, pretreatment with DIDS ($Cl^-$ channel blockers) but not LY294002 (PI3K inhibitors) completely abolished the LDL-induced upregulation of Egr-1 to the same extent as PD98059 (MEK inhibitors to inhibit Erk), as judged by Western blot and luciferase reporter assays. This is the first report, to our knowledge, that DIDS-sensitive $Cl^-$-channels play a key role in the LDL-induced cell proliferation of hAoSMCs via the activation of Erk1/2 and PI3K/Akt and the upregulation of Egr-1.

Effects of Green Tea Infusion on the Preneoplastic Lesions and Peroxidation in Rat Hepatocarcinogenesis

  • Kim, Hee-Seon;Kim, Hyung-Sook;Park, Haymie
    • 대한지역사회영양학회지
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    • 제2권5호
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    • pp.735-744
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    • 1997
  • The effect of green tea drinking on the hepatocellular chemical cacinogenesis have been studied. Placental glutathione S-transferase(GST-P) positive foci area in a liver tissue, contents of thiobarbituric acid reactive substances(TBARS), total cytochrome P450 and glucose 6-phospphatase(G6P) activity in hepatic microsomes were investigated. Weaning Sprague-Dawley male rats were fed AIN-76A diet with deionized water or green tea infusion, Rats of CTR and CTR+ groups were provided deionized water while GTI and GTI+ groups were provided green tea instead of deionized water for the entire experimental period of 13weeks. Rats of GTP and GTP + groups had deionized water for the first 6 weeks and switched to green tea for the last 7weeks of the experimental period. CTR+, GTI +, and GTP + groups were carcinogen treated groups, Diethylnitrosamine(DEN) was injected as a single dose of 200mg/kg body weight intraperitoneally after 4 weeks of feeding. 2-Acetyla-minofluorene(AAF) was used as a carcinogen proliferater and suppled in the diets of carcinogen treated rats as 0.02% content for the last 6weeks starting from 2weeks after DEN injection. Rats were sacrificed after 13week weeks of feeding. The area and number of GST-P positive foci detected in carcinogen treated rats were decreased by green tea ingestion but when timing and duration of green tea ingestion was delayed after promotion period as in GTP + group, GST-P positive foci were not decreased as much as in GTI+ group. TBARS contents of carcinogen treated rats decreased by 13weeks of green tea ingestion but GTP groups did not show statiscally significant differences. G6P activities tended to decrease by carcinogen treatment but changes were not statiscally significant by green tea ingestion. Total cytochrome P450 contents were increased by carcinogen treatment. Thirteen weeks of green tea ingestion (GTI) also increased to total cytochrome P450 contents while 7weeks of green tea ingestion(GTP) did show any effects. These results suggest that green tea has suppressive effects on hepatocellular chemical carcinogenesis probably through the activities of antioxidant compounds. (Korean J Community utrition 2(5) : 735∼744, 1997)

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Generation and Characterization of Monoclonal Antibodies to the Ogawa Lipopolysaccharide of Vibrio cholerae O1 from Phage-Displayed Human Synthetic Fab Library

  • Kim, Dain;Hong, Jisu;Choi, Yoonjoo;Han, Jemin;Kim, Sangkyu;Jo, Gyunghee;Yoon, Jun-Yeol;Chae, Heesu;Yoon, Hyeseon;Lee, Chankyu;Hong, Hyo Jeong
    • Journal of Microbiology and Biotechnology
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    • 제30권11호
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    • pp.1760-1768
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    • 2020
  • Vibrio cholerae, cause of the life-threatening diarrheal disease cholera, can be divided into different serogroups based on the structure of its lipopolysaccharide (LPS), which consists of lipid-A, core-polysaccharide and O-antigen polysaccharide (O-PS). The O1 serogroup, the predominant cause of cholera, includes two major serotypes, Inaba and Ogawa. These serotypes are differentiated by the presence of a single 2-O-methyl group in the upstream terminal perosamine of the Ogawa O-PS, which is absent in the Inaba O-PS. To ensure the consistent quality and efficacy of the current cholera vaccines, accurate measurement and characterization of each of these two serotypes is highly important. In this study, we efficiently screened a phage-displayed human synthetic Fab library by bio-panning against Ogawa LPS and finally selected three unique mAbs (D9, E11, and F7) that specifically react with Ogawa LPS. The mAbs bound to Vibrio cholerae vaccine in a dose-dependent fashion. Sequence and structure analyses of antibody paratopes suggest that IgG D9 might have the same fine specificity as that of the murine mAbs, which were shown to bind to the upstream terminal perosamine of Ogawa O-PS, whereas IgGs F7 and E11 showed some different characteristics in the paratopes. To our knowledge, this study is the first to demonstrate the generation of Ogawa-specific mAbs using phage display technology. The mAbs will be useful for identification and quantification of Ogawa LPS in multivalent V. cholerae vaccines.

Antioxidant and Apoptotic Effects of an Aqueous Extract of Urtica dioica on the MCF-7 Human Breast Cancer Cell Line

  • Fattahi, Sadegh;Ardekani, Ali Motevalizadeh;Zabihi, Ebrahim;Abedian, Zeinab;Mostafazadeh, Amrollah;Pourbagher, Roghayeh;Akhavan-Niaki, Haleh
    • Asian Pacific Journal of Cancer Prevention
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    • 제14권9호
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    • pp.5317-5323
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    • 2013
  • Breast cancer is the most prevalent cancer and one of the leading causes of death among women in the world. Plants and herbs may play an important role in complementary or alternative treatment. The aim of this study was to evaluate the antioxidant and anti-proliferative potential of Urtica dioica. The anti oxidant activity of an aqueous extract of Urtica dioica leaf was measured by MTT assay and the FRAP method while its anti-proliferative activity on the human breast cancer cell line (MCF-7) and fibroblasts isolated from foreskin tissue was evaluated using MTT assay. Mechanisms leading to apoptosis were also investigated at the molecular level by measuring the amount of anti and pro-apoptotic proteins and at the cellular level by studying DNA fragmentation and annexin V staining by flow cytometry. The aqueous extract of Urtica dioica showed antioxidant effects with a correlation coefficient of $r^2$=0.997. Dose-dependent and anti-proliferative effects of the extract were observed only on MCF-7 cells after 72 hrs with an $IC_{50}$ value of 2 mg/ml. This anti proliferative activity was associated with an increase of apoptosis as demonstrated by DNA fragmentation, the appearance of apoptotic cells in flow cytometry analysis and an increase of the amount of calpain 1, calpastatin, caspase 3, caspase 9, Bax and Bcl-2, all proteins involved in the apoptotic pathway. This is the first time such in vitro antiproliferative effect of aqueous extract of Urtica dioica leaf has been described for a breast cancer cell line. Our findings warrant further research on Urtica dioica as a potential chemotherapeutic agent for breast cancer.

백화사설초 메탄올 추출물에 의한 HL-60 세포고사과정에 있어서의 transcriptional factors 활성변화 연구 (Study on Transcriptional Factors Activation Change of HL-60 cell Apoptosis by Hedyotis Diffusa's Methanol Extract)

  • 박상구;이지현;문구;문석재;원진희;박래길
    • 대한한방종양학회지
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    • 제6권1호
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    • pp.67-79
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    • 2000
  • Objective : Hedyotis diffusa has been used as an anticancer agent for several decades in oriental medicine. We test whether the methanol extract of the herb affects transcriptional activation factors including $NF-{\kappa}B$ and AP-1. Methods : 1. HL-60 cells were treated with various concentrations(from 200 to $50{\mu}g/ml$) of methanol extract and $H_2O$ extract($200{\mu}g/ml$)of hedyotis diffusa, After 48h later, the cells were tested for viability by MTT assay. 2. The HL-60 cells were treated with $200{\mu}g/ml$ of methanol extract for the indicated periods. First. Nuclear extracts were isolated and incubated with oligonucleotide probe of $NF-{\kappa}B$ and AP-1. Second. Nuclear extracts were isolated and reacted with p50, p65. c-rel pan-Jun, c-Jun, JunB. JunD antibody on ice for 30min. Finally The cell lysates were prepared and analyzed by western blotting using anti-Fas, anti-FasL and anti-p53 antibody. Results : 1. The methanol extract decreases the viability of human lymphoid origin leukemia HL-60 cells in a dose-dependent manner. 2. $NF-{\kappa}B$ is rapidly activated by the addition of the methanol extract, reaches a peak at 30min and gradually returns to resting level. We confirm that $NF-{\kappa}B$ is a heterodimer mainly composed of p65 subunit with c-Rel. 3. Transcriptional activation of AP-1 is detected at 30min and reaches a maximum at 1hr after stimulation of the cells with the methanol extract. AP-1 is mainly composed with Jur-D and partially Jug-B proteins. 4. the methanol extract of Hedyotis diffusa induces the expression of Fas, Fas ligand and p53 proteins of HL-60 cells in a time dependent fashion. Conclusions : These results suggest that the methanol extract of Hedyotis diffusa exerts anticancer effects to induce the death of human leukomic HL-60 cells via activation of trascriptional factors such as $NF-{\kappa}B$ and AP-1, increase in expression of Fas mediated signalling proteins, and induction of tumor suppressor gene. p53.

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PDGF-BB에 의한 치주인대세포활성에 대한 TGF-{\beta}의 효과 (The Effect of TGF-{\beta}_1 on Cellular Activity of Periodontal Ligament Cells activated by PDGF-BB)

  • 백상철;박진우;서조영
    • Journal of Periodontal and Implant Science
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    • 제32권3호
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    • pp.457-473
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    • 2002
  • 이 연구는 배양된 치주인대세포에 TGF(Transforming growth factor)-${\beta}_1$과 PDGF(Plateletderived growth factor)-BB를 농도별로 혼합 주입해서 세포의 증식능, 단백질 및 교원질 합성능을 측정해 봄으로서 TGF-${\beta}_1$ 이 치주인대세포의 중식과 활성에 대한 PDGF-BB의 효과를 상승시킬 수 있은지 알아보고자 본 실험을 실시하였다. 교정치료를 위해 내원한 환자로 부터 건강한 제일소구치를 발거하여 치주인대세포률 분리, 배양하여 TGF-${\beta}_1$과 PDGF-BB를 동시에 주입한 군과 TGF-${\beta}_1$를 4, 24시간 전처리 배양한 군과 나누어 실험하였다. TGF-${\beta}_1$, PDGF-BB를 주입하지 않은군을 대조군으로 하여 DNA 합성능, 총단백질과 교원질 합성능을 측정하여 다음과 같은 결과를 얻었다. 치주인대세포에 TGF-${\beta}_1$과 PDGF-BB을 동시 주입하였을 때 DNA 합성능의 효과는 대조군에 비해 모든 군에서 증가된 양상을 보였으며 1ng/ml PDGF-BB 투여군에 비해 10ng/ml PDGF-BB 투여군에서 증가 양상이 높았고 PDGF-BB 단독 투여군보다 TGF-${\beta}_1$병용 투여군에서 DNA 합성능이 증가된 양상을 나타내었으며 5ng/ml TGF-${\beta}_1$과 10ng/ml PDGF-BB 투여군에서 가장 높은 증가 양상을 보였다. TGF-${\beta}_1$ 4시간과 24시간 전처리 배양군 양군 공히 lng/ml PDGF-BB 투여군을 제외한 모든 군에서 대조군에 비해 증가된 양상을 보였으며 lng/ml PDGF-BB 투여군에 비해 10ng/ml PDGF-BB 투여군에서 증가 양상이 더 높았고 PDGF-BB 단독 투여군보다 TGF-${\beta}_1$ 전 처리군에서 DNA 합성능이 증가된 양상을 나타내 였으며 5ng/ml TGF-${\beta}_1$ 전 처리 후 10ng/ml PDGF-BB 투여군에서 가장 높은 증가 양상을 보였다. 치주인대세포에 TGF-${\beta}_1$과 PDGF-BB을 동시 주입하였을 때 총단백질합성량은 대조군에 비해 모든 군에서 증가된 양상을 보였으며 lng/ml PDGF-BB 투여군에 비해 10ng/ml PDGF-BB 투여군에서 증가 양상이 더 높게 나타났다. PDGF-BB 단독 투여군보다 TGF-${\beta}_1$ 병용 투여군에서 총단백칠 합성양이 증가된 양상을 나타내었다. TGF-${\beta}_1$ 4과 24시간 전처리 배양군의 총단백질 합성양은 대조군에 비해 모든 군에서 증가된 양상을 보였으며 1ng/ml PDGF-BB 투여군에 비해 10ng/ml PDGF-BB 투여군에서 증가 양상이 더 높았고 TGF-${\beta}_1$ 전처리 배양군이 PDGF-BB 단독 투여군보다 총단백질 합성양이 증가된 양상을 나타내었다. TGF-111과 PDGF-BB를 동시 투여하였을 때 대조군에 비해 모든 군에서 교원질 합성능이 증가하는 경향을 나타내었으며, 비교원성단백질의 합성능은 1, 10ng/ml PDGF-BB 단독투여군을 제외하고 대조군에 비해 증가하는 경향을 보였다. 총단백질에 대한 교원질 합성의 상대적 비율 PDGF-BB 단독 투여군보다 TGF-${\beta}_1$ 병용 투여군에서 감소하는 정향을 나타내었다. TGF-${\beta}_1$ 4과 24시간 전처리 배양군의 교원질과 비교원성 단백질 합성능은 대조군에 비해 모든 군에서 교원질과 비교원성 단백질 합성능이 증가하는 경향을 나타내었으며 PDGF-BB 단독 투여군보다 TGF-${\beta}_1$ 병용 투여군에서 총단백질 합성양이 증가된 양상을 나타내었으며 그 정도는 TGF-${\beta}_1$의 농도 의존적인 양상을 보였다. 총단백질에 대한 교원질 합성의 상대적비율은 TGF-${\beta}_1$ 4,24시간전처리 배양군 모두에서 대조군에 비해 감소하는 경향을 나타내었다. 이상의 결과를 종합해 볼 때 치주인대세포에서 TGF-${\beta}_1$은 PDGF-BB의 기능을 조절하는 능력을 가지고 있으며 두 성장인자 주입시 동시주입시보다 TGF-${\beta}_1$을 전처리 해 줌으로써 PDGF-BB의 반응을 더욱 촉진시킬 수 있음을 알 수 있었다.

치주인대세포의 증식 및 세포활성에 미치는 $1,25-(OH)_2D_3$의 영향에 관한 연구 (THE EFFECT OF $1,25-(OH)_2D_3$ ON THE PROLIFERATION AND ALKALINE PHOSPHATASE ACTIVITY OF HUMAN PERIODONTAL LIGAMENT CELLS)

  • 국윤아;김상철;김형룡
    • 대한치과교정학회지
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    • 제25권3호
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    • pp.333-339
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    • 1995
  • [ $1,25-(OH)_2D_3$ ]가 치주인대세포의 증식에 미치는 영향과 조골세포 기능을 나타내는 지표이며 골의 석회화 과정에 관여하는 alkaline phosphatase의 활성도에 미치는 영향을 관찰하여 아직 확실히 밝혀져 있지 않은 치주인대조직에 대한 $1,25-(OH)_2D_3$의 생물학적 기능을 알아보고자 교정 치료 목적으로 발거된 치아로부터 치주인대세포를 배양하였다. $1,25-(OH)_2D_3$를 첨가하여 24시간 후 [${^3}H$]thymidine으로 DNA를 표지하여 세포의 증식을 관찰하였으며 $1,25-(OH)_2D_3$가 치주인대세포에서 조골세포의 표지효소인 alkaline phosphatase의 활성도에 미치는 영향을 24시간 또는 6일간 $1,25-(OH)_2D_3$ 처리후 측정한 결과 100nM농도의 $1,25-(OH)_2D_3$은 치주인대세포의 증식을 유의하게 증가시켰으며 10nM에서는 차이를 보이지 않았다. $1,25-(OH)_2D_3$을 24시간 첨가시 10nM에서는 ALP활성도는 $80.8\pm31.4$nmol로 서 대조군 $38.5\pm5.3$nmol에 비해 유의하게 증가하였으며 또한 $1,25-(OH)_2D_3$을 6일동안 첨가하였을때에도 10nM에서 $106.7\pm23.0$nmol로 대조군 $29.3\pm1.0$nmol에 비해 유의하게 증가되었다. 이상의 결과를 종합하면 $1,25-(OH)_2D_3$이 치주인대세포의 증식 및 세포기능을 시사하는 결과로 사료된다.

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'꼬리겨우살이'(Loranthus tanakae) 전초로부터 cyclofarnesane sesquiterpene glucoside의 분리 동정 및 세포독성 (Cyclofarnesane sesquiterpene glucoside from the whole plant of Loranthus tanakae and its cytotoxicity)

  • 주선우;김형근;오은지;고정환;이영근;강세찬;이대영;백남인
    • Journal of Applied Biological Chemistry
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    • 제62권1호
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    • pp.7-10
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    • 2019
  • 꼬리겨우살이(Loranthus tanakae) 전초를 80% MeOH 수용액으로 4회 반복 추출한 뒤, 감압 농축한 추출물을 ethyl acetate(EtOAc), n-butyl alcohol (n-BuOH)과 $H_2O$층으로 계통 분획을 실시하였다. n-BuOH 분획에 대하여 silica gel ($SiO_2$), octadecyl silica gel (ODS), Sephadex LH-20 column chromatographies를 반복실시하여 1종의 cyclofarnesane sesquiterpene glucoside 화합물을 분리 및 정제하였다. 스펙트럼 데이터를 분석하여 입체 구조를 포함한 화합물의 구조를 (1'R,3'S,5'R,8'S,2E,4E)-dihydrophaseic acid $3^{\prime}-O-{\beta}-{\text\tiny{D}}$-glucopyranoside로 구조동정 하였다. 이 화합물은 이번 실험을 통하여 꼬리겨우살이로 부터는 최초로 분리되었다. 분리한 단일 물질은 AGS (Caucasian gastric adenocarcinoma cells)와 Hepatocyte carcinoma cells에 대하여 $50{\mu}g/mL$ 이상에서 농도 의존적으로 유의한 정도의 세포독성을 보이는 것이 확인되었다.

Development of Natural Antioxidants and Whitening Agents for Cosmeceuticals

  • Kim, Jong-Pyung
    • 한국응용약물학회:학술대회논문집
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    • 한국응용약물학회 2007년도 Proceedings of The Convention
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    • pp.79-92
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    • 2007
  • Oxidative stress have known to be a risk factor for the degenerative processes and closely related to a lot of diseases. It is well established that antioxidants are good in protection and therapeutic means against oxidative damage. There is increasing interest in natural antioxidants and many natural antioxidants have been found and utilized as the possible protection for various diseases and skin aging. We have screened natural antioxidant agents for cosmeceuticals, nutraceuticals, and drugs as therapeutic and preventive means against oxidative stress, and have developed a number of novel antioxidants from various natural sources. A novel melanin synthesis inhibitor, Melanocin A, isolated from the metabolite of a fungal strain Eupenicillium shearii F80695 inhibited mushroom tyrosinase and melanin biosynthesis of B16 melanoma cells with $IC_{50}$ value of 9.0 nM and MIC value of $0.9\;{\mu}M$, respectively. Melanocin A also exhibited potent antioxidant activity by scavenging of DPPH and superoxide anion radicals. UV was found to increase the level of hydrogen peroxides and other reactive oxygen species (ROS) in skin tissues. This increase in ROS may not only alter the structure and function of many genes and proteins directly but may also modulate their expressions through signal transduction pathways and, ultimately, lead to skin damage. We investigated the effect of Melanocin A on UV-induced premature skin aging. Firstly, the effect of Melanocin A on UV-induced matrix metalloproteinase (MMP)-9 expression in an immortalized human keratinocyte cell line, HaCaT in vitro was investigated. Acute UV irradiation induced MMP-9 expression at both the mRNA and protein levels and Melanocin A suppressed this expression in a dose-dependent manner. We then investigated UV-induced skin changes in hairless mice in vivo by Melanocin A. Chronic exposure of hairless mouse dorsal skin to UV increased skin thickness and induced wrinkle formation and the gelatinase activities of MMP-2 and MMP-9. Moreover, Melanocin A significantly suppressed UV-induced morphologic skin changes and MMP-2 and MMP-9 expression. These results show that Melanocin A can prevent the harmful effects of UV that lead to skin aging. Therefore, we suggest that Melanocin A should be viewed as a potential therapeutic agent for preventing and/or treating premature skin aging. Terrein is a bioactive fungal metabolite isolated from Penicillium species. Terrein has a relatively simple structure and can be easily synthesized. However, the biologic effects of terrein are comparatively unknown. We found for the first time that terrein potently inhibit melanin production in melanocytes and has a strong hypopigmentary effect in a spontaneously immortalized mouse melanocyte cell line, Mel-Ab. Treatment of Mel-Ab cells with terrein (10-100 mM) for 4 days significantly reduced melanin levels in a dose-dependent manner. In addition, terrein at the same concentration also reduced tyrosinase activity. We then investigated whether terrein influences the extracellular signal-regulated protein kinase (ERK) pathway and the expression of microphthalmia-associated transcription factor (MITF), which is required for tyrosinase expression. Terrein was found to induce sustained ERK activation and MITF down-regulation, and luciferase assays showed that terrein inhibits MITF promoter activity in a dose-dependent manner. To elucidate the correlation between ERK pathway activation and a decreased MITF transcriptional level, PD98059, a specific inhibitor of the ERK pathway, was applied before terrain treatment and found to abrogate the terrein-induced MITF attenuation. Terrein also reduced the tyrosinase protein level for at least 72 h. These results suggest that terrain reduces melanin synthesis by reducing tyrosinase production via ERK activation, and that this is followed by MITF down-regulation.

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