• Proceedings of the Korean Society of Applied Pharmacology
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• 2003.11a
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• pp.79-79
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• 2003

Recently diabetes has been found to be associated with metabolic bone diseases such as osteoporosis. In the present study, attempts have been made-to explore the effect of high glucose in bone formation. Osteoblast-like UMR 106 cells were treated with high glucose (22mM, 33mM, 44mM) for 1 or 2 days. High glucose significantly inhibited proliferation of UMR106 cells in a time- and dose- dependent manner as evidenced by MTT assay. For the evaluation of collagen synthesis, UMR 106 cells were cultured in high glucose media (44mM) for 24 h and the ratio of collagen content to total protein was measured. In addition, gene expression pattern of type I collagen was assessed by RT-PCR. The high concentration of glucose inhibited a collagen synthesis, a marker of bone formation activity. JNK, c- Jun N-terminal Kinase, is known to play an important role in stress-associated cell death. In this regard, we tested to determine whether high glucose has any effect on JNK activity. It has been found that treatment of high glucose induced phosphorylation of JNK. On the other hand, ERK phosphorylation was inhibited by high glucose in a dose-dependent manner. Taken together, Therefore these results indicate that inhibition of proliferation in UMR 106 cells following high glucose is related to JNK/ERK containing signal pathways. This study showed high glucose concentration could alter the bone metabolism leading to defective bone formation, suggesting that high glucose due to diabetes may playa significant role in the development of metabolic bone disease.

• Journal of Life Science
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• v.21 no.11
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• pp.1518-1525
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• 2011

Sorafenib is the only approved systemic, therapeutic agent for hepatocellular carcinoma (HCC). The use of Ginseng Extract (GE) in cancer patients is growing worldwide; however, drug interaction between sorafenib and GE has not been illuminated. Four different human cancer cell lines including HepG2 were used and immunocompetent mice were implanted subcutaneously with a mouse HCC cell line. Treatment with low dose GE stimulated cell growth, while a high dose inhibited growth. pERK (phosphorylation of extracellular signal-regulated kinase) was concomitantly increased and decreased respective of different doses of GE. Antitumoral effect of sorafenib decreased in non-proliferating phase cells but was sensitized after low dose GE (LDG) treatment. PD98059 (ERK phosphorylation inhibitor) efficiently blocked ERK phosphorylation, resulting in loss of sorafenib sensitization even after LDG treatment. In the HCC mouse model, LDG alone slightly increased tumor size while sorafenib alone significantly decreased it. However, a combination of LDG and sorafenib significantly decreased tumor size compared with sorafenib alone. Increase of pERK was observed in some normal mice organs and mild inflammatory change was observed in some of these organs, suggesting pERK activation by LDG may cause unexpected toxicity in normal cells. GE, dose-dependently, induced stimulation or inhibition in some human cancer cell lines. Combinational use of GE and sorafenib possibly potentiated an antitumoral response to sorafenib. pERK level has been provided as a potential predictive marker for sorafenib. Our result may suggest GE's dual effects in relation to pERK level in HCC cancer cell lines, and that certain doses of GE can sensitize sorafenib.

• Biomolecules & Therapeutics
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• v.24 no.4
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• pp.395-401
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• 2016

Endochondral bone formation is the process by which mesenchymal cells condense into chondrocytes, which are ultimately responsible for new bone formation. The processes of chondrogenic differentiation and hypertrophy are critical for bone formation and are therefore highly regulated. The present study was designed to investigate the effect of aloe-emodin on chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Aloe-emodin treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. ATDC5 cells were treated with aloe-emodin and stained with alcian blue. Compared with the control cells, the ATDC5 cells showed more intense alcian blue staining. This finding suggested that aloe-emodin induced the synthesis of matrix proteoglycans and increased the activity of alkaline phosphatase. Aloe-emodin also enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, BSP and RunX2 in a time-dependent manner. Furthermore, examination of the MAPK signaling pathway showed that aloe-emodin increased the activation of extracellular signal-regulated kinase (ERK), but had no effect on p38 and c-jun N-terminal kinase (JNK). Aloe-emodin also enhanced the protein expression of BMP-2 in a time-dependent manner. Thus, these results showed that aloe-emodin exhibited chodromodulating effects via the BMP-2 or ERK signaling pathway. Aloe-emodin may have potential future applications for the treatment of growth disorders.

• Journal of Life Science
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• v.17 no.8 s.88
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• pp.1039-1045
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• 2007

Glioblastoma multiforme (GBM) is the most frequently occurring brain cancer. Although the existence of cancer stem cells (CSCs) in GBM has been established, there is little evidence to explain the link between CSCs and chemoresistance. In this study, we investigated that only a few cells of A172 and established GBM2 survived after 1,3-bis(2chloroethyl)-1-nitrosourea (BiCNU) exposures and these sur-vived cells resist the subsequent BiCNU treatment. In addition, these BiCNU-resistant small pop-ulations derived from GBM cells increased the phosphorylations of Erk and Akt and highly expressed CD133 stem cell surface marker. Furthermore, we observed that the BiCNU-resistant cancer cells de-rived from GBM have grown tumors when transplanted into severe combined immuno-deficient (SCID) mouse brain. These results demonstrate that BiCNU-resistant subpopulation cells derived from GBM have cancer stem-like cell properties. Therefore, it may provide provide further evidence that CSCs in GBM have chemotherapeutic drug resistance.

• Biomolecules & Therapeutics
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• v.20 no.3
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• pp.299-305
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• 2012

Endochondral bone formation is the process by which mesenchymal cells condense to become chondrocytes, which ultimately form new bone. The process of chondrogenic differentiation and hypertrophy is critical for bone formation and as such is regulated by many factors. In this study, we aimed to indentify novel factors that regulate chondrogenesis. We investigated the possible role of isopsoralen in induction of chondrogenic differentiation in clonal mouse chondrogenic ATDC5 cells. Isopsoralen treatment stimulated the accumulation of cartilage nodules in a dose-dependent manner. Further, ATDC5 cells treated with isopsoralen were stained more intensely with Alcian blue than control cells, suggesting that isopsoralen increases the synthesis of matrix proteoglycans. Similarly, isopsoralen markedly induced the activation of alkaline phosphatase activity compared with control cells. Isopsoralen enhanced the expressions of chondrogenic marker genes such as collagen II, collagen X, OCN, Smad4 and Sox9 in a time-dependent manner. Furthermore, isopsoralen induced the activation of extracellular signal-regulated kinase (ERK) and p38 MAP kinase, but not that of c-jun N-terminal kinase (JNK). Isopsoralen significantly enhanced the protein expression of BMP-2 in a time-dependent manner. PD98059 and SB 203580, inhibitors of ERK and p38 MAPK, respectively, decreased the number of stained cells treated with isopsoralen. Taken together, these results suggest that isopsoralen mediates a chondromodulating effect by BMP-2 or MAPK signaling pathways, and is therefore a possible therapeutic agent for bone growth disorders.

• Journal of Korean Neurosurgical Society
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• v.43 no.2
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• pp.97-104
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• 2008

Objective: Transient receptor potential vanilloid subfamily type 1 (TRPV1), a most specific marker of the nociceptive primary afferent, is expressed in peptidergic and non-peptidergic primary afferents innervating skin and viscera. However, its expression in sensory fibers to skeletal muscle is not well known. In this study, we studied the neurochemical characteristics of TRPV1-positive primary afferents to skeletal muscles. Methods: Sprague-Dawley rats were injected with total $20{\mu}l$ of 1% fast blue (FB) into the gastrocnemius and erector spinae muscle and animals were perfused 4 days after injection. FB-positive cells were traced in the L4-L5 (for gastrocnemius muscle) and L2-L4 (for erector spinae muscle) dorsal root ganglia. The neurochemical characteristics of the muscle afferents were studied with multiple immunofluorescence with TRPV1, calcitonin gene-related peptide (CGRP) and $P2X_3$. To identify spinal neurons responding to noxious stimulus to the skeletal muscle, 10% acetic acids were injected into the gastrocnemius and erector spinae muscles and expression of phospho extracellular signal-regulated kinase (pERK) in spinal cords were identified with immunohistochemical method. Results: TRPVl was expressed in about 49% of muscle afferents traced from gastrocnemius and 40% of erector spinae. Sixty-five to 60% of TRPV1-positive muscles afferents also expressed CGRP. In contrast, expression of $P2X_3$ immnoreaction in TRPV1-positive muscle afferents were about 20%. TRPV1-positive primary afferents were contacted with spinal neurons expressing pERK after injection of acetic acid into the muscles. Conclusion: It is consequently suggested that nociception from skeletal muscles are mediated by TRPV1-positive primary afferents and majority of them are also peptidergic.

• Molecules and Cells
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• v.39 no.5
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• pp.389-394
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• 2016

Dovitinib (TKI258) is a small molecule multi-kinase inhibitor currently in clinical phase I/II/III development for the treatment of various types of cancers. This drug has a safe and effective pharmacokinetic/pharmacodynamic profile. Although dovitinib can bind several kinases at nanomolar concentrations, there are no reports relating to osteoporosis or osteoblast differentiation. Herein, we investigated the effect of dovitinib on human recombinant bone morphogenetic protein (BMP)-2-induced osteoblast differentiation in a cell culture model. Dovitinib enhanced the BMP-2-induced alkaline phosphatase (ALP) induction, which is a representative marker of osteoblast differentiation. Dovitinib also stimulated the translocation of phosphorylated Smad1/5/8 into the nucleus and phosphorylation of mitogen-activated protein kinases, including ERK1/2 and p38. In addition, the mRNA expression of BMP-4, BMP-7, ALP, and OCN increased with dovitinib treatment. Our results suggest that dovitinib has a potent stimulating effect on BMP-2-induced osteoblast differentiation and this existing drug has potential for repositioning in the treatment of bone-related disorders.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.3
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• pp.337-344
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• 2002

Runx2, a Runt-related osteoblast-specific transcription factor, is essential for osteoblast differentiation and function. Runx2 was identified as a key regulator of osteoblast-specific gene expression through its binding to the OSE2 element present in these genes. However, little is known about the signaling mechanism regulating Runx2 activity. This study examines the role of protein kinase C (PKC) pathway and mitogen-activated protein kinase (MAPK) pathway in regulating Runx2 and bone marker genes (osteopontin; OP, osteocalcin; OC). Luciferase assay and Northern blot analysis suggested that the stimulation of PKC by PMA increased transcription activity of Runx2 and bone marker genes (OP and OC) and also increased expression of Runx2. The stimulation of MAPK by okadaic acid increased transcription activity of Runx2 and bone marker genes (OP and OC). Pretreatment with PD98059 (Erk pathway inhibitor) and SB203580 (P38 pathway inhibitor) prior to PMA treatment decreased PMA stimulated Runx2 activity. Together these results indicate that both PKC and MAPKs are involved in the regulation of Runx2 activity and also the stimulation of Runx2 transcriptional activity by the PKC pathway is through activation of MAPK pathway.

• IMMUNE NETWORK
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• v.22 no.3
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• pp.25.1-25.11
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• 2022

IL-34 can promote osteoclast differentiation and activation, which may contribute to steroid-induced osteonecrosis of the femoral head (ONFH). Animal model was constructed in both BALB/c and IL-34 deficient mice to detect the relative expression of inflammation cytokines. Micro-CT was utilized to reveal the internal structure. In vitro differentiated osteoclast was induced by culturing bone marrow-derived macrophages with IL-34 conditioned medium or M-CSF. The relative expression of pro-inflammation cytokines, osteoclast marker genes, and relevant pathways molecules was detected with quantitative real-time RT-PCR, ELISA, and Western blot. Up-regulated IL-34 expression could be detected in the serum of ONFH patients and femoral heads of ONFH mice. IL-34 deficient mice showed the resistance to ONFH induction with the up-regulated trabecular number, trabecular thickness, bone value fraction, and down-regulated trabecular separation. On the other hand, inflammatory cytokines, such as TNF-α, IFN-γ, IL-6, IL-12, IL-2, and IL-17A, showed diminished expression in IL-34 deficient ONFH induced mice. IL-34 alone or works in coordination with M-CSF to promote osteoclastogenesis and activate ERK, STAT3, and non-canonical NF-κB pathways. These data demonstrate that IL-34 can promote the differentiation of osteoclast through ERK, STAT3, and non-canonical NF-κB pathways to aggravate steroid-induced ONFH, and IL-34 can be considered as a treatment target.

• Journal of the Korean Society of Food Culture
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• v.37 no.3
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• pp.248-255
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• 2022

Spinach (Spinacia oleracea L.), a green leafy vegetable, is well known as a functional food due to its biological activities. Vascular calcification is associated with several disease conditions including atherosclerosis, diabetes, and chronic kidney disease (CKD), and is known to raise the risk of cardiovascular diseases related morbidity and mortality. However, there are no previous studies that have investigated the effects of fermented spinach exract (FSE) against aortic and its underlying mechanisms. Therefore, this study investigated the effects and action of possible mechanisms of FSE on inorganic phosphate (PI)-induced vascular calcification in ex vivo mouse aortic rings. PI increased vascular calcification through calcium deposition in ex vivo aortic rings. FSE inhibited calcium accumulation and osteogenic key marker, runt-related transcription factor 2 (Runx2), and bone Morphogenetic Protein 2 (BMP-2) protein expression in ex vivo aortic rings. And, FSE inhibited PI-induced extracellular signal-regulated kinase (ERK) and p38 phosphorylation in ex vivo aortic rings. These results show that FSE can prevent vascular calcification which may be a crucial way for the prevention and treatment of vascular disease association with vascular calcification.