• Mass Spectrometry Letters
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• 제11권4호
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• pp.118-124
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• 2020

An analytical method was developed for hypoxia-inducible factor (HIF) stabilizers based on QuEChERS (Quick, Easy, Cheap, Effective, Rugged, and Safe) sample preparation and liquid chromatography-high resolution mass spectrometry analysis. HIF stabilizers potentially enhance the performance of athletes, and hence, they have been prohibited. However, the analysis of urinary HIF stabilizers is not easy owing to their unique structure and characteristics. Hence, we developed the QuEChERS preparation technique for a complementary method and optimized the pH, volume of extraction solvent, and number of extractions. We found that double extraction with 1% of formic acid in acetonitrile provided the highest recovery of HIF stabilizers. Moreover, the composition of the mobile phase was also optimized for better separation of molidustat and IOX4. The developed method was validated in terms of its precision, detection limit, matrix effect, and recovery for ISO accreditation. To the best of our knowledge, this is the first demonstration of the application of the QuEChERS method, which is suitable as a complementary analytical method, in antidoping.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Dietary and Medicinal Antimutgens and Anticarcinogens
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• pp.199-199
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• 2001

Both hypoxia and insulin induce same target genes including vascular endothelial growth factor (VEGF), glycolitic enzymes and glucose transporters. However these two signals eventually trigger quite different metabolic pathways. Hypoxia induces glycolysis for anaerobic ATP production, while insulin increase glycolysis for lipogenesis and energy storage. Hypoxia-induced gene expression is mediated by Hypoxia-inducible Factorl (HIF-1) that consists of HIF-1 $\alpha$ and $\beta$ subunit.(omitted)

• 동의생리병리학회지
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• 제18권6호
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• pp.1613-1616
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• 2004

The cellular response to hypoxia is controlled to a large degree by the transcription factor Hypoxia-inducible factor-1(HIF-1). HIF-1 is a transcription factor that is activated by hypoxia and plays a critical role in the development of the cancer phenotype. HIF-1 regulates transcription of a number of genes crucial for tumor survival under hypoxic conditions, including vascular endothelial growth factor(VEGF), erythropoietin(Epo) and several glycolytic enzymes. Tumors in which hypoxia can not induce HIF-1 transcriptional activity remain small and fail to metastasize. In this study, we examined whether aqueous root extract of Ailanthus altissima (REA) downregulate HIF-1, VEGF and p53, and raise the possibility that depletion of these proteins and the anti proliferative activities of REA have any effects on inhibition of angiogenesis in MCF-7 cells. Pharmacologic targeting of specific signal transduction pathways related to oncogenic transformation is a promising approach in cancer treatment. Therefore, REA could be a candidate drug for further clinical development.

• BMB Reports
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• 제49권12호
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• pp.687-692
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• 2016

We recently reported the anti-inflammatory effects of 3-(naphthalen-2-yl(propoxy)methyl)azetidine hydrochloride (KHG26792) on the ATP-induced activation of the NFAT and MAPK pathways through the P2X7 receptor in microglia. To further investigate the underlying mechanism of KHG26792, we studied its protective effects on hypoxia-induced toxicity in microglia. The administration of KHG26792 significantly reduced the hypoxia-induced expression and activity of caspase-3 in BV-2 microglial cells. KHG26792 also reduced hypoxia-induced inducible nitric oxide synthase protein expression, which correlated with reduced nitric oxide accumulation. In addition, KHG26792 attenuated hypoxia-induced protein nitration, reactive oxygen species production, and NADPH oxidase activity. These effects were accompanied by the suppression of hypoxia-induced protein expression of hypoxia-inducible factor 1-alpha and NADPH oxidase-2. Although the clinical relevance of our findings remains to be determined, these data results suggest that KHG26792 prevents hypoxia-induced toxicity by suppressing microglial activation.

• 한국독성학회:학술대회논문집
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• 한국독성학회 2001년도 International Symposium on Signal transduction in Toxicology
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• pp.41-83
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• 2001

Under low oxygen tension, cells increase the transcription of specific genes that are involved in angiogenesis, erythropoiesis and glycolysis. Hypoxia-induced gene expression primarily depends on the stabilization of the subunit of Hypoxia-Inducible Factor-1 (HIF-1), which acts as a heterodimeric transactivator.(omitted)

• Molecules and Cells
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• 제44권10호
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• pp.710-722
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• 2021

Hypoxia, or low oxygen tension, is a hallmark of the tumor microenvironment. The hypoxia-inducible factor-1α (HIF-1α) subunit plays a critical role in the adaptive cellular response of hypoxic tumor cells to low oxygen tension by activating gene-expression programs that control cancer cell metabolism, angiogenesis, and therapy resistance. Phosphorylation is involved in the stabilization and regulation of HIF-1α transcriptional activity. HIF-1α is activated by several factors, including the mitogen-activated protein kinase (MAPK) superfamily. MAPK phosphatase 3 (MKP-3) is a cytoplasmic dual-specificity phosphatase specific for extracellular signal-regulated kinase 1/2 (Erk1/2). Recent evidence indicates that hypoxia increases the endogenous levels of both MKP-3 mRNA and protein. However, its role in the response of cells to hypoxia is poorly understood. Herein, we demonstrated that small-interfering RNA (siRNA)-mediated knockdown of MKP-3 enhanced HIF-1α (not HIF-2α) levels. Conversely, MKP-3 overexpression suppressed HIF-1α (not HIF-2α) levels, as well as the expression levels of hypoxia-responsive genes (LDHA, CA9, GLUT-1, and VEGF), in hypoxic colon cancer cells. These findings indicated that MKP-3, induced by HIF-1α in hypoxia, negatively regulates HIF-1α protein levels and hypoxia-responsive genes. However, we also found that long-term hypoxia (>12 h) induced proteasomal degradation of MKP-3 in a lactic acid-dependent manner. Taken together, MKP-3 expression is modulated by the hypoxic conditions prevailing in colon cancer, and plays a role in cellular adaptation to tumor hypoxia and tumor progression. Thus, MKP-3 may serve as a potential therapeutic target for colon cancer treatment.

• Molecules and Cells
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• 제42권11호
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• pp.763-772
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• 2019

Periodontitis is characterized by the loss of periodontal tissues, especially alveolar bone. Common therapies cannot satisfactorily recover lost alveolar bone. Periodontal ligament stem cells (PDLSCs) possess the capacity of self-renewal and multilineage differentiation and are likely to recover lost alveolar bone. In addition, periodontitis is accompanied by hypoxia, and hypoxia-inducible $factor-1{\alpha}$ ($HIF-1{\alpha}$) is a master transcription factor in the response to hypoxia. Thus, we aimed to ascertain how hypoxia affects runt-related transcription factor 2 (RUNX2), a key osteogenic marker, in the osteogenesis of PDLSCs. In this study, we found that hypoxia enhanced the protein expression of $HIF-1{\alpha}$, vascular endothelial growth factor (VEGF), and RUNX2 ex vivo and in situ. VEGF is a target gene of $HIF-1{\alpha}$, and the increased expression of VEGF and RUNX2 proteins was enhanced by cobalt chloride ($CoCl_2$, $100{\mu}mol/L$), an agonist of $HIF-1{\alpha}$, and suppressed by 3-(5'-hydroxymethyl-2'-furyl)-1-benzyl indazole (YC-1, $10{\mu}mol/L$), an antagonist of $HIF-1{\alpha}$. In addition, VEGF could regulate the expression of RUNX2, as RUNX2 expression was enhanced by human VEGF ($hVEGF_{165}$) and suppressed by VEGF siRNA. In addition, knocking down VEGF could decrease the expression of osteogenesis-related genes, i.e., RUNX2, alkaline phosphatase (ALP), and type I collagen (COL1), and hypoxia could enhance the expression of ALP, COL1, and osteocalcin (OCN) in the early stage of osteogenesis of PDLSCs. Taken together, our results showed that hypoxia could mediate the expression of RUNX2 in PDLSCs via $HIF-1{\alpha}$-induced VEGF and play a positive role in the early stage of osteogenesis of PDLSCs.

• Molecules and Cells
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• 제45권8호
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• pp.534-536
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• 2022

• Molecules and Cells
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• 제22권3호
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• pp.291-299
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• 2006

Vitexin, a natural flavonoid compound identified as apigenin-8-C-${\beta}$-D-glucopyranoside, has been reported to exhibit antioxidative and anti-inflammatory properties. In this study, we investigated its effect on hypoxiainducible factor-$1{\alpha}$ (HIF-$1{\alpha}$) in rat pheochromacytoma (PC12), human osteosarcoma (HOS) and human hepatoma (HepG2) cells. Vitexin inhibited HIF-$1{\alpha}$ in PC12 cells, but not in HOS or HepG2 cells. In addition, it diminished the mRNA levels of hypoxia-inducible genes such as vascular endothelial growth factor (VEGF), smad3, aldolase A, enolase 1, and collagen type III in the PC12 cells. We found that vitexin inhibited the migration of PC12 cells as well as their invasion rates, and it also inhibited tube formation by human umbilical vein endothelium cells (HUVECs). Interestingly, vitexin inhibited the hypoxia-induced activation of c-jun N-terminal kinase (JNK), but not of extracellular-signal regulated protein kinase (ERK), implying that it acts in part via the JNK pathway. Overall, these results suggest the potential use of vitexin as a treatment for diseases such as cancer.

• Biomolecules & Therapeutics
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• 제23권1호
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• pp.19-25
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• 2015

Vascular endothelial growth factor (VEGF) is an important regulator of neovascularization. Hypoxia inducible nitric oxide (NO) enhanced the expression of VEGF and thymosin beta-4 ($T{\beta}4$), actin sequestering protein. Here, we investigated whether NO-mediated VEGF expression could be regulated by $T{\beta}4$ expression in HeLa cervical cancer cells. Hypoxia inducible NO production and VEGF expression were reduced by small interference (si) RNA of $T{\beta}4$. Hypoxia response element (HRE)-luciferase activity and VEGF expression were increased by the treatment with N-(${\beta}$-D-Glucopyranosyl)-N2-acetyl-S-nitroso-D, L-penicillaminamide (SNAP-1), to generate NO, which was inhibited by the inhibition of $T{\beta}4$ expression with $T{\beta}4$-siRNA. In hypoxic condition, HRE-luciferase activity and VEGF expression were inhibited by the treatment with $N^G$-monomethyl-L-arginine (L-NMMA), an inhibitor to nitric oxide synthase (NOS), which is accompanied with a decrease in $T{\beta}4$ expression. VEGF expression inhibited by L-NMMA treatment was restored by the transfection with pCMV-$T{\beta}4$ plasmids for $T{\beta}4$ overexpression. Taken together, these results suggest that $T{\beta}4$ could be a regulator for the expression of VEGF via the maintenance of NOS activity.