• Biomedical Science Letters
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• v.15 no.2
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• pp.141-146
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• 2009

Paclitaxel, an antimicrotubule agent, binds to beta-tubulin in the microtubule and stabilizes the polymer, thereby repressing dynamic instability. Here, we have demonstrated that microtubule cytoskeletal architecture involved in regulation of the COX-2 expression in chondrocyte treated with paclitaxel. Paclitaxel enhanced COX-2 expression and prostaglandin E2 production, as indicated by the Western blot analysis, reverse transcriptase PCR(RT-PCR) and immunofluorescence staining, and $PGE_2$ assay, respectively. In our previous data have shown that paclitaxel treatment stimulated activation of ERK-1/2 and p38 kinase(Im et al., 2009). SB203580, an inhibitor of p38 kinase, blocked the induction of COX-2 expression by paclitaxel. Also PD98059, an inhibitor of ERK-1/2 kinase was blocked the induced COX-2 expression. These results indicate that activation of ERK-1/2 and p38 kinase is required for COX-2 expression induced by paclitaxel in rabbit articular chondrocytes.

• The Journal of the Korean bone and joint tumor society
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• v.13 no.2
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• pp.105-112
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• 2007

Purpose: Recent studies have shown increased levels of cyclooxygenase-2 (COX-2) in various human malignancies to include various bone and soft tissue tumors. However, little is known with regard to COX-2 expression patterns in chondroid tumors. Materials and Methods: Immunohistochemistry assays were performed for COX-2 in enchondromas (n=10), chondroblastomas (n=11), chondromyxoid fibromas (n=5), conventional chondrosarcomas (n=17), clear cell chondrosarcomas (n=7), and mesenchymal chondrosarcomas (n=6). Results: Among the benign chondroid tumors, chondroblastomas revealed characteristic strong positivity in 6 of 11 cases(54.5%). All enchondromas and chondromyxoid fibromas were negative except in one case. In conventional chondrosarcomas, three cases(17.6%) were strongly reactive with COX-2 and all positive cases represented grade III chondrosarcomas. Clear cell chondrosarcomas were found to be focally positive in two cases(28.5%), while all mesenchymal chondrosarcomas were negative. Conclusions: These findings suggest that COX-2 overexpression in conventional chondrosarcoma may represent an advanced histologic grade. Interestingly, expression of COX-2 in chondroblastomas could be an important factor for inducing peritumoral inflammatory changes in these specific tumors.

• Journal of Life Science
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• v.19 no.10
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• pp.1396-1402
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• 2009

Hizikia fusiforme is a kind of edible brown seaweed that grows mainly in the northwest Pacific including Korea, Japan and China, and has been widely used as food in Korea. Induction of cyclooxygenase-2 (COX-2) expression and prostaglandin $E_2$ ($PGE_2$) production is thought to have beneficial immunomodulatory effects in acute and chronic inflammatory disorders. In this study, we investigated the effects of extracts of H. fusiforme on the expression of COX-2 and production of $PGE_2$ in U937 human pre-monocytic cell models. In U937 cells stimulated with phorbol 12-myristate 13-acetate (PMA) to mimic inflammation, methanol extract of H. fusiforme (MEHF) and ethanol extract of H. fusiforme (EEHF), but not water extract of H. fusiforme (WEHF), inhibited PMA-induced expression of both COX-2 protein and mRNA, which was associated with inhibition of $PGE_2$ production. To investigate the mechanism by which MEHF and EEHF inhibit COX-2 gene expression and $PGE_2$ production, we examined the activation of nuclear factor-kappaB (NF-$\kappa$B) in U937 cells. Pre-treatment with MEHF and EEHF significantly attenuated the PMA-induced IkappaB degradation and prevented nuclear translocation of NF-$\kappa$B. Taken together, these findings provide important new insights into the possible molecular mechanisms of the anti-inflammatory activity of H. fusiforme.

• Natural Product Sciences
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• v.3 no.1
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• pp.19-28
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• 1997

Constitutive cyclooxygenase (COX-I) is present in cells under physiological conditions, whereas inducible cyclooxygenase (COX-II) is induced by some cytokines, mitogens, and endotoxin presumably in pathological conditions such as inflammation. We have evaluated the inhibitory effects of solvent fractionated extracts of natural products on the activities of COX-I and COX-II. Oxygen uptake COX assay was performed, as a primary screening from the tissue extracts of bovine seminal vesicles (BSV), by monitoring the initial rate of oxygen uptake using an oxygen electrode. Additionally, we evaluated plant extracts for the inhibitory effects of COX-I (in HEL cells) and COX-II (in lipopolysaccharide activated J774A.1 macrophages) using thin layer chromatography of prostanoids produced from $^{14}C-labelled$ arachidonic acid (AA). The use of such models of COX-I and COX-II assay will lead to the identification of specific inhibitors of cyclooxygenases with presumably less side effects than present therapies. Inhibitory effects of 50 kinds of plant extracts on the COX-I and COX-II activities were determined and the active fractions were found in the ethyl acetate fractions of Dryopteris crassirhizoma (roots), Amomum cardamomum (roots), Triticum aestivum (seeds), Perilla sikokiana (leaves), Anemarrhena asphodeloides (roots). Especially, the ethyl acetate fraction of Dryopteris crassirhizoma (roots), which exhibited the strong inhibition against BSV COX $(IC_{50},\;65.4\;{\mu}g/ml)$, COX-I $(IC_{50},\;8.5\;{\mu}g/ml)$, and COX-II $(IC_{50},\;17.2\;{\mu}g/ml)$, is under investigation to isolate active principles using activity-guided fractionation method.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.80-80
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• 2002

Cyclooxygenase-2 (COX-2) is an inducible enzyme expressed in response to a variety of cytokines. The presence of oncogenic ras has been associated with sustained induction of COX-2, which confers resistance to apoptosis. Contrary to the above notion, we found that MCF10A-ras cells treated with an anti-tumor agent, ET-18-O-$CH_3$, underwent apoptosis as revealed by proteolytic cleavage of poly(ADP-ribose)polymerase, pro-caspase 3 activity, and TUNEL staining, while the same treatment caused an increased expression of COX-2 as well as the elevated production of prostaglandin E$_2$(PGE$_2$).(omitted)

• Journal of Physiology & Pathology in Korean Medicine
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• v.19 no.3
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• pp.749-752
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• 2005

We investigated the effects of electroacupuncture (EA) on the expression of cyclooxygenase in the spinal cord of acute inflammatory pain model. Inflammation was induced by an intraplantar injection of 1% carrageenan into the right hind paw of Sprague-Dawley. Bilateral 2 Hz EA stimulation with 0.5 mA, 1 mA and 3 mA were delivered at those acupoints corresponding to Zusanli and Sanyinjiao in man via the needles in carrageenan-injected rats. Three hours after carrageenan injection, effects of EA on cyclooxygenase (COX) expression were observed in the dorsal horn of the spinal cord using immunohistochemical method. The immunoreaction of COX-1 tended to increase in the superficial laminae and the neck of the dorsal horn as compared with normal. The COX-2 immunoreaction in the carrageenan-injected rat was also significantly increased in the all regions of the dorsal horn as compared with normal one. However, COX-1 immunoreaction in carrageenan-injected rat were decreased in the superficial laminae and neck of the dorsal horn by low intensity of EA stimulation. Except high intensity of EA stimulation in the superficial laminae, COX-2 expression was attenuated in all regions of the dorsal horn by all types of EA treatment. It is concluded that EA treatment may attenuate inflammatory pain in carrageenan-injected rat through modulating expression of COX-2 in the dorsal horn of the spinal cord.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.20 no.1
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• pp.25-36
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• 1994

It is weal known that bacterial lipopolysaccharide (LPS) stimulates prostaglandin synthesis in various experimental system via enhancing the expression of cylooxygenase-2 (COX-2). This study was designed to characterize U)5-induced prostaglandin synthesis in mouse peritoneal macrophages LPS-stimulated prostaglandin synthesis in macrophages with short term exposure was not so much prominent, but there was a burst in prostaglandin synthesis 8 hours after the LPS treatment and this u·as accompanied with the increase of cyclooxygenase activity, Dexamethasone markedly inhibited prostaglandin synthesis in this system. Metabolic label ins data supported above observations and thus, it could be concluded that LPS induces the do novo synthesis of COX-2 by which it stimulates the prostaglandin synthesis in mouse peritoneal macrophages, These data suggested that this experimental model system could be used for the screening procedure of COX-2 selective inhibitors. Ketoprofen, a non steroidal anti inflammatory agent, appeared to inhibit COX-1 relatively more selectively than COX-2.

• The Korean Journal of Physiology and Pharmacology
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• v.10 no.1
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• pp.45-50
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• 2006

Melittin-induced pain model has been known to be very useful for the study of pain mechanism. Melittin-induced nociceptive responses are reported to be modulated by the changes in the activity of excitatory amino acid receptor, calcium channel, spinal serotonin receptor and extracellular signaling-regulated kinase. The present study was undertaken to investigate the role of cyclooxygenase (COX) in the melittin-induced nociception. Changes in mechanical threshold, flinchings and paw thickness were measured before and after intraplantar injection of melittin in the rat hind paw. Also studied were the effects of intraperitonealy administered diclofenac (25 mg & 50 mg/kg), piroxicam (10 mg & 20 mg/kg) and meloxicam (10 mg & 20 mg/kg) on the melittin-induced nociceptions. Intraplantar injection of melittin caused marked reduction of mechanical threshold that was dose-dependently attenuated by non-selective COX inhibitor (diclofenac) and selective COX-1 inhibitor (piroxicam), but not by COX-2 inhibitor (meloxicam). Melittin-induced flinchings were strongly suppressed by non-selective COX and COX-1 inhibitor, but not by COX-2 inhibitor. None of the COX inhibitors had inhibitory effects on melittin-induced increase of paw thickness (edema). These experimental findings suggest that COX-1 plays an important role in the melittin-induced nociceptive responses.

• Asian Pacific Journal of Cancer Prevention
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• v.13 no.1
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• pp.315-318
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• 2012

Objective: Cyclooxygenase-2 (COX-2) has been claimed to play role in carcinogenesis and be related to a bad prognosis in tumours. The aim of this study was to investigate the relationship between COX-2 expression and clinical and pathological parameters in early and advanced stage lung cancer patients. Materials and Methods: A total of 73 patients with lung cancer (27 adenocarcinomas, 33 squamous cell carcinomas, 4 large cell carcinomas and 9 small cell cancer) were analysed retrospectively. COX-2 expression was evaluated by immunohistochemistry in resection materials or lung biopsies. Tumor cells demonstrating more intense staining than smooth muscle and endothelial cells were recorded as COX-2 positive. We investigated the correlation between increased COX-2 expression and histological type of the tumor, the stage of the disease and survival. Results: COX-2 expression was observed in 55% of the adenocarcinomas, 45% of the squamous cell carcinomas and 22% of the small cell carcinomas. No correlation was apparent between COX-2 expression and disease stage, histological type and the survival. Conclusion: The results of this study do not support COX-2 expression as an independent prognostic factor in lung cancer. However, since results of the literature are different, further studies made in larger series are needed.

• Journal of Gastric Cancer
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• v.6 no.4
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• pp.284-290
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• 2006

Purpose: Many previous studies have suggested that cyclooxygenase-2 (COX-2) over expression is closely related to angiogenesis. However, few have reported the relationship between COX-2 and lymphangiogenesis which is still unclear, The aim of this study was to determine the relationship between COX-2 expression and lymphangiogenetic factor, VEGF-C, in human gastric cancer and to correlate COX-2 and VEGF-C expression with other clinocopathological features to investigate whether COX-2 contributes to lymphangiogenesis and enhances lymph node metastasis. Materials and Methods: One hundred patients who underwent curative radical surgery in Hanyang University hospital from July 1998 to June 2001 were selected. The expression of COX-2 and VEGF-C were detected by using immunohistochemistry, and the relationships between these two parameters and several clinicopathological factors (gender, stage, lymph node status, tumor location, Lauren classification and angioinvasion) were determined. Results: Increased COX-2 expression was found in 86 of 100 tumor samples (86%) and in 70 of 100 tumor samples (70%) with VEGF-C. A high correlation between VEGF-C expression and lymph node metastasis was observed (P=0.033) along as well as COX-2 expression (P=0.012). Also, there was a significant correlation between COX-2 and VEGF-C expression (P=0.026), yet no correlation were found between COX-2 and VEGF-C expression and other clinicopathological parameters. Conclusion: Our study suggests that COX-2 expression contributes to lymphangiogenesis by mediating VEGF-C and finally promoting lymph node metastasis.