title: Expression of 15-PGDH is downregulated by COX-2 in gastric cancer.
abstract: To explore the proteins regulated by cyclooxygenase-2 (COX-2) in gastric cancer, the expression plasmid of COX-2siRNA was constructed and transfected into gastric cancer cell line SGC7901. Then, two-dimensional electrophoresis and the PDQuest software analysis were applied to discover the differentially expressed proteins. The differential protein spots were analyzed by matrix-assisted laser desorption/ionization time of flight mass spectrometry. Fourteen differentially expressed proteins between the two cell lines were identified. 15-Hydroxyprostaglandin dehydrogenase [NAD(+)] (15-PGDH), a key enzyme in prostaglandin degradation, was identified as an upregulated protein in SGC7901 cells transfected with the COX-2siRNA plasmid. To further explore whether the 15-PGDH is regulated by COX-2, western blotting and immunocytochemical assay were performed to detect the expression of 15-PGDH in different cell lines with different expression level of COX-2. The results showed that the expression of 15-PGDH was upregulated (128.57%) as COX-2 was suppressed by small interfering RNA and downregulated (51.72%) as COX-2 was enhanced by COX-2 cDNA transfection in gastric cancer cells. In tissue specimens with gastric cancer, there was a decreased expression of 15-PGDH and an increased expression of COX-2 simultaneously. A significantly negative correlation of 15-PGDH expression was found to COX-2 level, tumor differentiation, tumor, lymph node, metastasis (TNM) staging and lymph node metastasis of gastric cancer. All the results suggest that 15-PGDH is downregulated by COX-2 in human gastric cancer and may contribute to the carcinogenesis and development of human gastric cancer in combination with COX-2.
authors.affiliation: State key Laboratory of Cancer Biology and Institute of Digestive Diseases, Xijing Hospital, Fourth Military Medical University, 15 Changle West Road, Shaanxi Province, Xi'an 710032, China.
authors.forename: Zhenxiong
authors.initials: Z
authors.lastname: Liu
authors.forename: Xin
authors.initials: X
authors.lastname: Wang
authors.forename: Yuanyuan
authors.initials: Y
authors.lastname: Lu
authors.forename: Shuang
authors.initials: S
authors.lastname: Han
authors.forename: Faming
authors.initials: F
authors.lastname: Zhang
authors.forename: Huihong
authors.initials: H
authors.lastname: Zhai
authors.forename: Ting
authors.initials: T
authors.lastname: Lei
authors.forename: Jie
authors.initials: J
authors.lastname: Liang
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Kaichun
authors.initials: K
authors.lastname: Wu
authors.forename: Daiming
authors.initials: D
authors.lastname: Fan
mesh_terms: D000230:Adenocarcinoma / Q000378:metabolism* / Q000473:pathology; D015153:Blotting, Western; D045744:Cell Line, Tumor; D051546:Cyclooxygenase 2 / Q000096:biosynthesis*; D015536:Down-Regulation; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D015870:Gene Expression; D006801:Humans; D006911:Hydroxyprostaglandin Dehydrogenases / Q000096:biosynthesis*; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D011379:Prognosis; D034741:RNA, Small Interfering; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013274:Stomach Neoplasms / Q000378:metabolism* / Q000473:pathology; D014162:Transfection
chemical_list: D034741:RNA, Small Interfering; D006911:Hydroxyprostaglandin Dehydrogenases; C035859:15-hydroxyprostaglandin dehydrogenase; D051546:Cyclooxygenase 2