PURPOSE: In addition to cyclooxygenase-2 (COX-2) which is related to prostaglandin E2 synthesis, other enzymes such as cytosolic phospholipase A2 (cPLA2), microsomal prostaglandin E2 synthase-1 (mPGES-1), and 15-prostaglandin dehydrogenase (15-PGDH) have been suggested to be related to carcinogenesis of colorectal cancer (CRC). The aim of this study was to investigate the roles of cPLA2, COX-2, mPGES-1, and 15-PGDH in tumor progression. MATERIALS AND METHODS: cPLA2, COX-2, mPGES-1, 15-PGDH, and vascular endothelial growth factor (VEGF) expressions were immunohistochemically examined in 89 CRC, and their expressions were compared with each other or clinicopathologic parameters as well as VEGF as tumor progression parameters. RESULTS: cPLA2 was expressed in 54.5%, COX-2 in 80.5%, mPGES-1 in 96.4%, 15-PGDH in 46.1%, and VEGF in 65.9%. The expression of cPLA2 correlated with VEGF expression. COX-2 expression was correlated with the depth of invasion, tumor stage, cPLA2, and VEGF expressions. Moreover, VEGF revealed the highest expression in the tissues positive for both cPLA2 and COX-2. Furthermore, 15-PGDH expression was inversely correlated with VEGF expression. CONCLUSION: The present study demonstrates that cPLA2 and mPGES-1, in addition to COX-2, are constitutively overexpressed, and that 15-PGDH might be attenuated in colorectal cancer. Furthermore, cPLA2 and 15-PGDH as well as COX-2 could have an important role in tumor progression.
Aged ; Colorectal Neoplasms/*enzymology ; Cyclooxygenase 2/*metabolism ; Female ; *Gene Expression Regulation, Enzymologic ; Group IV Phospholipases A2/*metabolism ; Humans ; Hydroxyprostaglandin Dehydrogenases/*metabolism ; Immunohistochemistry ; Intramolecular Oxidoreductases/metabolism ; Male ; Middle Aged

PURPOSE: Gastric carcinoma tissues release high level of prostaglandin E2 (PGE2) when compared to non-neoplastic mucosa, and cyclooxygenase-2 (COX-2), which is the rate-limiting enzyme in prostaglandin (PG) biosynthesis, is often overexpressed in gastric carcinomas and during gastric carcinogenesis. However, little is known about the expression of 15-hydroxyprostaglandin dehydrogenase (15-PGDH), the key enzyme responsible for the biological inactivation of PG, in gastric carcinomas. MATERIALS AND METHODS: We investigated the expression of 15-PGDH in 28 cases of advanced gastric carcinomas by Western blot analysis and also the relation between its expression and the gene promoter methylation. RESULTS: 15-PGDH expression was significantly decreased in gastric carcinomas compared to corresponding non-neoplastic tissues and inversely correlated with the expression of proliferating cell nuclear antigen in gastric carcinomas. However, there was no correlation between 15-PGDH expression and pathological findings such as nodal metastasis and vascular invasion. Promoter hypermethylation of 15-PGDH gene was not detected in carcinomas, with only a negligible expression of the enzyme. CONCLUSION: Our results suggested that 15-PGDH has tumor suppressor activity in gastric carcinomas.
Aged ; Base Sequence ; DNA Methylation ; DNA Primers/genetics ; DNA, Neoplasm/genetics ; Female ; Humans ; Hydroxyprostaglandin Dehydrogenases/genetics/*metabolism ; Male ; Middle Aged ; Promoter Regions, Genetic ; Stomach Neoplasms/*enzymology/genetics

Colon cancer is one of the major leading causes of cancer-related deaths in the Western countries. In Korea, the incidence of colon cancer is increasing due to changes in environment and lifestyle such as diet. Chemoprevention strategy using non-steroidal anti-inflammatory drugs (NSAIDs) has been under intensive clinical and epidemiological research as these drugs suppress colorectal cancer. The best known targets of NSAIDs are cyclooxygenase (COX) enzymes, which convert arachidonic acid to prostaglandins (PGs) and thromboxane. Among these PGs, prostaglandin E2 (PGE2) can promote tumor growth by binding its receptors and activating signal pathways which control cell proliferation, migration, apoptosis, and angiogenesis. Therefore, COX inhibition is promising approach for chemoprevention of colorectal cancer. However, the prolonged use of COX-2 inhibitors is associated with unacceptable cardiovascular side effects. Thus, new targets involved in PGs metabolism are under investigation. 15-hydroxyprostaglandin dehydrogenase (15-PGDH), a key metabolic enzyme of PGE2, was up-regulated in normal colonic epithelium, but decreased in colon cancer. Recent findings suggest that 15-PGDH is involved in the neoplastic progression of initiated colonic epithelial cells. Also, new players related with PGs metabolism including prostaglandin transporter (PGT) and microsomal prostaglandin E synthase (mPGES) were reported to play a role in colorectal cancer development. This review presents current knowledge about the role of prostaglandins and associated proteins in colorectal cancer development and progression.
Anti-Inflammatory Agents, Non-Steroidal/therapeutic use ; Colonic Neoplasms/drug therapy/*etiology/prevention & control ; Cyclooxygenase 2/metabolism ; Cyclooxygenase Inhibitors/pharmacology/therapeutic use ; Humans ; Hydroxyprostaglandin Dehydrogenases/antagonists & inhibitors/metabolism ; Prostaglandins/metabolism/*physiology

BACKGROUND/AIMS: The role of prostaglandin E2 (PGE2) in the modulation of cell growth is well established in colorectal cancer. The aim of this study was to elucidate the significance of 15-hydroxyprostaglandin dehydrogenase (15-PGDH) down-regulation on the prognosis of hepatocellular carcinoma (HCC) patients. METHODS: The expression of 15-PGDH in HCC cell lines and resected HCC tissues was investigated, and the correlation between 15-PGDH expression and HCC cell-line proliferation and patient survival was explored. RESULTS: The interleukin-1-beta-induced suppression of 15-PGDH did not change the proliferation of PLC and Huh-7 cells in the MTS [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The induction of 15-PGDH by transfection in HepG2 cells without baseline 15-PGDH expression was suppressed at day 2 of proliferation compared with empty-vector transfection, but there was no difference at day 3. Among the 153 patients who received curative HCC resection between 2003 and 2004 at our institution, 15-PGDH expression was observed in resected HCC tissues in 56 (36.6%), but the 5-year survival rate did not differ from that of the remaining 97 non-15-PGDH-expressing patients (57.1% vs 59.8%; P=0.93). Among 50 patients who exhibited baseline 15-PGDH expression in adjacent nontumor liver tissues, 28 (56%) exhibited a reduction in 15-PGDH expression score in HCC tissues, and there was a trend toward fewer long-term survivors compared with the remaining 22 with the same or increment in their 15-PGDH expression score in HCC tissues. CONCLUSIONS: The prognostic significance of 15-PGDH down-regulation in HCC was not established in this study. However, maintenance of 15-PGDH expression could be a potential therapeutic target for a subgroup of HCC patients with baseline 15-PGDH expression in adjacent nontumor liver tissue.
Adolescent ; Adult ; Aged ; Carcinoma, Hepatocellular/*diagnosis/mortality/pathology ; Down-Regulation ; Female ; Hep G2 Cells ; Humans ; Hydroxyprostaglandin Dehydrogenases/*metabolism ; Immunohistochemistry ; Kaplan-Meier Estimate ; Liver Neoplasms/*diagnosis/mortality/pathology ; Male ; Middle Aged ; Prognosis ; Young Adult

15-Hydroxyprostaglandin dehydrogenase (15-PGDH) is downregulated during the early stages of colorectal carcinogenesis. The aim of the present study was to investigate the potential role of 15-PGDH in normal-appearing colorectal mucosa as a biomarker for predicting colorectal neoplasms. We obtained paired tumor and normal tissues from the surgical specimens of 32 sporadic colorectal cancer patients. mRNA expression of 15-PGDH was measured using a quantitative real-time PCR assay. We evaluated the association between 15-PGDH mRNA expression in normal-appearing mucosa, the presence of synchronous adenoma, and the cumulative incidence of metachronous adenoma. The relative 15-PGDH expression of normal-appearing mucosa in patients with synchronous adenoma was significantly lower than in patients without synchronous adenoma (0.71 vs 1.00, P = 0.044). The patients in the lowest tertile of 15-PGDH expression in normal-appearing mucosa were most likely to have synchronous adenoma (OR: 10.5, P = 0.024). Patients with low 15-PGDH expression in normal-appearing mucosa also demonstrated more advanced stage colorectal cancer (P = 0.045). However, there was no significant difference in the cumulative incidence of metachronous adenoma according to 15-PGDH mRNA expression in normal-appearing mucosa (P = 0.333). Hence, 15-PGDH in normal-appearing colorectal mucosa can be a useful biomarker of field effect for the prediction of sporadic synchronous neoplasms.
Aged ; Colorectal Neoplasms/*diagnosis/enzymology/pathology ; Down-Regulation ; Female ; Humans ; Hydroxyprostaglandin Dehydrogenases/genetics/*metabolism ; Intestinal Mucosa/*enzymology ; Male ; Middle Aged ; Neoplasm Staging ; Neoplasms, Multiple Primary/enzymology/pathology ; Neoplasms, Second Primary/enzymology/pathology ; Odds Ratio ; Predictive Value of Tests ; RNA, Messenger/metabolism ; Real-Time Polymerase Chain Reaction ; Risk Factors ; Tumor Markers, Biological/*metabolism