BACKGROUND: Recent evidence indicates that elevated COX-2 expression is associated with the carcinogenesis of numerous neoplasms. In this study, we investigated COX-2 expression in various thyroid specimens in order to elucidate its physiological role in pathologic conditions, and to evaluate the efficiency of COX-2 protein expression as a molecular marker of malignancy in the thyroid gland. METHODS: COX-2 expression was studied immunohistochemically in 19 papillary carcinomas, 8 follicular carcinomas, 14 follicular adenomas, 2 H rthle cell carcinomas, 4 H rthle cell adenomas, 8 nodular hyperplasias, 3 Graves' diseases, 3 Hashimoto's thyroiditis, 2 medullary carcinomas, 1 anaplastic carcinoma, and 20 normal thyroid tissues. RESULTS: COX-2 staining was not seen in any of the normal thyroid, Graves' disease, or nodular hyperplasia specimens. In contrast, COX-2 staining was observed in all of papillary carcinomas, Hashimoto's thyroiditis, H rthle cell carcinomas, and H rthle cell adenomas tissues. Moreover, 7 of 8 follicular carcinomas and 11 of 14 follicular adenomas showed COX-2 staining. CONCLUSION: These results indicate that COX-2 is not useful as a marker of malignancy. Since COX-2 expression was evident in follicular adenomas and in papillary and follicular carcinomas. Thus, the enzyme may be involved in the early process of thyroid tumorigenesis.
Human ; *Immunohistochemistry ; Isoenzymes/*analysis ; Prostaglandin-Endoperoxide Synthase/*analysis ; Thyroid Nodule/*enzymology/*pathology ; Tumor Markers, Biological/*analysis

BACKGROUND/AIMS: Recent studies have shown that cyclooxygenase-2 (COX-2) may be involved in the process of invasion, growth and apoptosis in colorectal carcinoma and in the growth and tumorigenesis in familial adenomatous polyposis. This study was conducted to determine the significance of the expression of COX-2 in gastric and colorectal adenomas. METHODS: Forty-nine samples of gastric adenoma and fifty-seven samples of colorectal adenoma were obtained by endoscopic mucosal resection or polypectomy from 106 patients from January 2000 to July 2003. COX-2 expression was determined by immunohistochemistry. Correlation between COX-2 expression and several clinical factors were compared in each gastric and colorectal adenomas. RESULTS: The expression of COX-2 in epithelial cells was significantly higher in the group with large adenoma (>1 cm) compared with the group with small adenoma ( Adenoma/enzymology/*pathology ; Aged ; Colorectal Neoplasms/enzymology/*pathology ; English Abstract ; Female ; Humans ; Immunohistochemistry ; Male ; Middle Aged ; Prostaglandin-Endoperoxide Synthase/*analysis ; Stomach Neoplasms/enzymology/*pathology

OBJECTIVETo explore the effects of Triptolide (TP) on TNFalpha-induced cell proliferation and expressions of cyclooxygenase-2 (COX-2), inducible nitric oxide synthase (iNOS) and their inducing products PGE2, NO in human rheumatoid arthritis synovial fibroblasts (RASF).

METHODSFibroblasts (RASF) were obtained from synovial tissue of patients with RA and were cultured in vitro. RASF were stimulated with TNFalpha(20 microg/L) in the presence or absence of TP(0 - 100 microg/L) for 20 h. The RASF proliferation was determined by (3)H-TdR incorporation, and the productions of PGE2 and NO in culture supernatants of RASF were detected with competitive ELISA and enzyme reduction of nitrate. Expressions of COX-2 and iNOS mRNA in RASF were analyzed by semi-quantitative RT-PCR. Expressions of COX-2 and iNOS protein were estimated by Western-blot method and cellular enzyme immunoassay in synovial fibroblasts. NF-kappaB activity in whole-cell extract of RASF was also measured by an ELISA-based method.

RESULTSTP (>20 microg/L) down-regulated markedly TNFalpha-induced COX-2 and iNOS mRNA and protein expression, and their inducing products PGE2 and NO of synovial fibroblasts. This effect was positively correlated with TP concentrations. NF-kappaB activity in TNFalpha-stimulated synovial cells was suppressed profoundly by TP treatment (IC(50) approximately 35microg/L). The activity of NF-kappaB was correlated with the levels of COX-2 and iNOS expression in TNFalpha-stimulated RASF. No change was observed in proliferation of synovial cells after treatment of TP.

CONCLUSIONTP could significantly down-regulate TNFalpha-induced COX-2, iNOS expression and production of PGE2, NO in human RASF, which is associated with the suppression of NF-kappaB activity.

Arthritis, Rheumatoid ; drug therapy ; metabolism ; Cyclooxygenase 2 ; Diterpenes ; pharmacology ; Epoxy Compounds ; Fibroblasts ; metabolism ; Gene Expression Regulation ; drug effects ; Humans ; Isoenzymes ; analysis ; genetics ; Membrane Proteins ; NF-kappa B ; metabolism ; Nitric Oxide Synthase ; analysis ; genetics ; Nitric Oxide Synthase Type II ; Phenanthrenes ; pharmacology ; Prostaglandin-Endoperoxide Synthases ; analysis ; genetics ; RNA, Messenger ; analysis ; Synovial Membrane ; cytology ; metabolism ; Tumor Necrosis Factor-alpha ; pharmacology

IL-1beta is known promote cyclooxygenase-2 (COX- 2) and matrix metalloproteinase-2 (MMP-2) expression. This study focuses on the characterization of the signaling cascade associated with IL-1beta-induced matrix metalloproteinase-2 (MMP- 2) regulation in human chondrocytes. The decrease in collagen levels in the conditioned media was prevented by a broad spectrum MMP inhibitor, suggesting that IL-1beta promotes the proteolytic process leading to MMP-2 activation. IL-1beta-related MMP-2 expression was found to be dependent on prostaglandin E2 (PGE2) production. In addition, the induction of COX-2 and MMP-2 was inhibited by the pretreatment of chondrocytes with a SB203580 or Ro 31-8220, indicating the involvement of protein kinase C (PKC) or p38 mitogen-activated protein kinase (MAPK). However, there is no cross-talk between PKC and p38 MAPK in the IL-1beta-induced MMP-2 activation. Taken together, these results demonstrated that IL-1beta induces MMP-2 expression through the PGE2-dependent mechanism in human chondrocytes.
Chondrocytes/drug effects/*enzymology/metabolism ; Dinoprostone/analysis/*metabolism ; Gelatinase A/analysis/*biosynthesis ; Humans ; Indoles/pharmacology ; Interleukin-1/*pharmacology ; Isoenzymes/antagonists & inhibitors/metabolism ; Nitrobenzenes/pharmacology ; Phosphorylation/drug effects ; Prostaglandin-Endoperoxide Synthase/metabolism ; Protein Kinase C/antagonists & inhibitors/metabolism ; Research Support, Non-U.S. Gov't ; Sulfonamides/pharmacology ; Up-Regulation ; p38 Mitogen-Activated Protein Kinases/metabolism