• Journal of Microbiology and Biotechnology
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• v.19 no.9
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• pp.918-921
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• 2009

In the present study, we examined the inhibitory effects of protein tyrosine phosphatase (PTPase) inhibitors, including sodium orthovanadate (SOV), ammonium molybdate (AM), and iodoacetamide (IA), on cell growth, accumulation of astaxanthin, and PTPase activity in the photosynthetic algae Haematococcus lacustris. PTPase activity was assayed spectrophotometrically and was found to be inhibited 60% to 90% after treatment with the inhibitors. SOY markedly abolished PTPase activity, significantly activating the accumulation of astaxanthin. These data suggest that the accumulation of astaxanthin in H. lacustris results from the concerted actions of several PTPases.

• BMB Reports
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• v.45 no.5
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• pp.317-322
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• 2012

2-deoxy-D-glucose(2DG)-caused endoplasmic reticulum (ER) stress inhibits protein phosphorylation at tyrosine residues. However, the accurate regulatory mechanisms, which determine the inflammatory response of chondrocytes to ER stress via protein tyrosine phosphorylation, have not been systematically evaluated. Thus, in this study, we examined whether protein phosphorylation at tyrosine residues can modulate the expression and glycosylation of COX-2, which is reduced by 2DG-induced ER stress. We observed that protein tyrosine phosphatase (PTP) inhibitors, sodium orthovanadate (SOV), and phenylarsine oxide (PAO) significantly decreased expression of ER stress inducible proteins, glucose-regulated protein 94 (GRP94), and CCAAT/ enhancer-binding-protein- related gene (GADD153), which was induced by 2DG. In addition, we demonstrated that SOV and PAO noticeably restored the expression and glycosylation of COX-2 after treatment with 2DG. These results suggest that protein phosphorylation of tyrosine residues plays an important role in the regulation of expression and glycosylation during 2DG-induced ER stress in rabbit articular chondrocytes.

• The Korea Journal of Herbology
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• v.22 no.3
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• pp.27-37
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• 2007

Objectives: Hepatocellular carcinoma is the most common primary malignant tumor of the liver worldwide. In-Jin-Ho-Tang(IJHT) has been used as a traditional Chinese herbal medicine since ancient time. and today it is widely applied as a medication for jaundice which is associated with inflammation in liver. In this study, I investigated whether methanol extract of IJHT induced HepG2 cancer cell death. Methods: Cytotoxic activity of IJHT on HepG2 cells was using XTT assay. Apoptosis induction by Ros A in HCT116 cells was verified by the induction of cleavage of poly ADP-ribose polymerase (PARP). and activation of caspase-3, -8 and -9. The release of cytochrome c from mitochondria to cytosol. the level of Bcl-2 and Bax and the expression of p53 and p21 were examined by western blotting analysis. Furthermore, MAPKs activation was analyzed by western blotting analysis. Results: IJHT induced apoptosis in HepG2 cells. And treatment of IJHT resulted in the release of cytochrome c into cytosol, decreased anti-apoptotic Bcl-2, and increased pri-apoptotic Bax expression. IJHT markedly inactivated extracellular signal-regulated kinase (ERK1/2), and activated p38 mitogen-activated protein (MAP) kinase. Sodium orthovanadate (SOV), a phosphatase inhibitor, to reverse IJHT-induced ERK1/2 inactivation and SB203580, a specific p38 MAP Kinase inhibitor efficiently blocked apoptosis of HepG2. Thus, IJHT induces apoptosis in HepG2 cells via MAP kinase modulation. Conclusion: These results indicated that IJHT has some potential for use as an anti-cancer agent.