• Molecules and Cells
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• 제21권2호
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• pp.206-212
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• 2006

We have established in culture a spontaneously immortalized bovine embryonic fibroblast (BEF) cell line that has lost p53 and $p16^{INK4a}$ functions. MyoD is a muscle-specific regulator capable of inducing myogenesis in a number of cell types. When the BEF cells were transduced with MyoD they differentiated efficiently to desmin-positive myofibers in the presence of 2% horse serum and 1.7 nM insulin. The myogenic differentiation of this cell line was more rapid and obvious than that of C2C12 cells, as judged by morphological changes and expression of various muscle regulatory factors. To confirm that lack of the p53 and $p16^{INK4a}$ pathway does not prevent MyoD-mediated myogenesis, we established a cell line transformed with SV40LT (BEFV) and introduced MyoD into it. In the presence of 2% horse serum and 1.7 nM insulin, the MyoD-transduced BEFV cells differentiated like the MyoD-transduced BEFS cells, and displayed a similar pattern of expression of muscle regulatory proteins. Taken together, our results indicate that MyoD overexpression overcomes the defect in muscle differentiation associated with immortalization and cell transformation caused by the loss of p53 and Rb functions.

• BMB Reports
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• 제53권11호
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• pp.605-610
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• 2020

Skeletal myogenesis is a complex process that is finely regulated by myogenic transcription factors. Recent studies have shown that saturated fatty acids (SFA) can suppress the activation of myogenic transcription factors and impair the myogenic differentiation of progenitor cells. Despite the increasing evidence of the roles of miRNAs in myogenesis, the targets and myogenic regulatory mechanisms of miRNAs are largely unknown, particularly when myogenesis is dysregulated by SFA deposition. This study examined the implications of SFA-induced miR-183-5p on the myogenic differentiation in C2C12 myoblasts. Long-chain SFA palmitic acid (PA) drastically reduced myogenic transcription factors, such as myoblast determination protein (MyoD), myogenin (MyoG), and myocyte enhancer factor 2C (MEF2C), and inhibited FHL1 expression and myogenic differentiation of C2C12 myoblasts, accompanied by the induction of miR-183-5p. The knockdown of FHL1 by siRNA inhibited myogenic differentiation of myoblasts. Interestingly, miR-183-5p inversely regulated the expression of FHL1, a crucial regulator of skeletal myogenesis, by targeting the 3'UTR of FHL1 mRNA. Furthermore, the transfection of miR-183-5p mimic suppressed the expression of MyoD, MyoG, MEF2C, and MyHC, and impaired the differentiation and myotube formation of myoblasts. Overall, this study highlights the role of miR-183-5p in myogenic differentiation through FHL1 repression and suggests a novel miRNA-mediated mechanism for myogenesis in a background of obesity.

• Natural Product Sciences
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• 제23권1호
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• pp.35-39
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• 2017

D-chiro-inositol (DCI) is a secondary messenger in insulin signal transduction. It is produced in vivo from myo-inositol via action of epimerase. In this study, we evaluated antitumor activity of DCI against human breast cancer both in vitro and in vivo. In order to determine the inhibitory effects of DCI on growth of human breast cancer cells (MDA-MB-231), two different assessment methods were implemented: MTT assay and mouse xenograft assay. MTT assay demonstrated downturn in cell proliferation by DCI treatment (1, 5, 10, 20 and 40 mM) groups by 18.3% (p < 0.05), 17.2% (p < 0.05), 17.5% (p < 0.05), 18.4% (p < 0.05), and 24.9% (p < 0.01), respectively. Also, inhibition of tumor growth was investigated in mouse xenograft model. DCI was administered orally at the dose of 500 mg/kg and 1000 mg/kg body weight to treat nude mouse for 45 consecutive days. On the 45th day, tumor growth of DCI (500 mg/kg and 1000 mg/kg) groups was suppressed by 22.1% and 67.6% as mean tumor volumes were $9313.8{\pm}474.1mm^3$ and $3879.1{\pm}1044.1mm^3$, respectively. Furthermore, breast cancer stem cell (CSC) phenotype ($CD44^+/C24^-$) was measured using flow cytometry. On the 46th day, CSC ratios of DCI (500 mg/kg) and co-treatment with doxorubicin (4 mg/kg) and DCI (500 mg/kg) group decreased by 24.7% and 53.9% (p < 0.01), respectively. Finally, from tumor recurrence assay, delay of 5 days in the co-treatment group compared to doxorubicin (4 mg/kg) alone group was observed. Based on these findings, we propose that DCI holds potential as an anti-cancer drug for treatment of breast cancer.

• 한국식품영양과학회지
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• 제45권12호
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• pp.1732-1739
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• 2016

아이스플랜트(Mesembryanthemum crystallinum)의 일반성분과 cyclitol 화합물을 분석하였으며, 기능성 식품의 소재로 활용 가능성을 알아보기 위하여 추출물의 용매분획별 항산화 효과 및 항당뇨 활성 등을 검정하였다. 무기질 함량은 K와 Na가 각각 $1,213.33{\pm}2.52$와 $545.53{\pm}12.01mg/100g$으로 가장 많았고, S, Ca, P, Mg의 순이었다. Cyclitol 화합물의 함량은 D-pinitol이 $4.04{\pm}0.08mg/g$으로 가장 많았으며, chiro-inositol과 myo-inositol은 각각 $2.82{\pm}0.01$과 $0.25{\pm}0.01mg/g$으로 비교적 적게 함유되어 있었다. 용매분획별 총페놀 함량은 chloroform과 ethyl acetate 분획에서 각각 $35.80{\pm}1.33$과 $23.70{\pm}0.62mg\;GAE/g$으로 많았다. DPPH, ABTS, FRAP 및 lipid/MA assay에 의한 항산화 활성은 공통적으로 chloroform 분획에서 가장 높은 활성을 나타내었으며, ethyl acetate 분획에서 비교적 높은 활성을 나타내었다. 항산화 활성은 용매분획별 총페놀 함량과 비례적이었다. 한편 항당뇨 효과는 ${\alpha}-glucosidase$ 저해활성에서 모든 용매분획에서 50% 이상의 활성을 나타내었으며, ethyl acetate, butanol 및 chloroform 분획에서 각각 $90.33{\pm}0.40$, $87.98{\pm}0.16$ 및 $86.38{\pm}0.51%$의 높은 활성을 나타내었다. ${\alpha}-Amylase$ 저해 활성은 $25.63{\pm}1.45{\sim}60.34{\pm}2.67%$로서 ${\alpha}-glucosidase$ 저해 활성보다는 낮았으나, 용매분획별 저해 활성은 유사한 경향을 보였다. 이와 같은 연구 결과로 볼 때 아이스플랜트가 항산화 및 항당뇨 기능성 천연소재로 활용이 가능할 것으로 생각되었다.