title: In vivo inhibition of cyclooxygenase-2 by a selective phosphorothioated oligonucleotide.
abstract: Inhibition of cyclooxygenase-2 (cox-2) is considered to be anti-inflammatory, whereas inhibition of the constitutive isozyme cox-1 causes renal and gastrointestinal toxicity. Therefore, to achieve an optimal anti-inflammatory effect, an inhibitor should be cox-2 selective without inhibiting cox-1. For this purpose, 10 different cox-2-selective phosphorothioated oligonucleotides (S-oligos) were tested to inhibit the cox-2 enzyme selectively in vivo. An aqueous solution of these S-oligos (3 mg/kg body weight) was injected intraperitoneally (i.p.) into male Sprague-Dawley rats with colitis induced by trinitrobenzene sulfonic acid (TNBS). The colonic levels of cox-2 protein, mRNA, myeloperoxidase (MPO), and prostaglandin E2 (PGE2) were increased significantly on day 1 and remained significantly elevated until day 7 post-TNBS administration, whereas cox-1 remained unaltered. Two S-oligos were found to be effective in reducing the level of cox-2 protein selectively without any effect on the cox-1. The effective S-oligo, but not the mismatched control oligo, reduced the tissue levels of PGE2 and MPO activity significantly. The effective S-oligo reduced the level of cox-2 but not the cox-1 mRNA significantly, whereas a mismatched or a sense control oligo did not affect the levels of these isoforms. M-fold analysis demonstrated extensive secondary structure formation in the cox-2 mRNA. These findings demonstrate that only a few selected sites in the cox-2 target mRNA are accessible in vivo, probably because of the presence of secondary structures. Suppression of cox-2 protein, PGE2, and MPO activity by the S-oligo might prove to be an anti-inflammatory property.
authors.affiliation: Department of Biochemistry, Faculty of Medicine, Kuwait University, Kuwait. Islam@hsc.kuniv.edu.kw
authors.forename: I
authors.initials: I
authors.lastname: Khan
authors.forename: F M
authors.initials: FM
authors.lastname: Al-Awadi
authors.forename: N
authors.initials: N
authors.lastname: Thomas
mesh_terms: D000818:Animals; D015415:Biomarkers; D003092:Colitis / Q000188:drug therapy* / Q000201:enzymology; D003106:Colon / Q000737:chemistry / Q000187:drug effects / Q000201:enzymology; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D015232:Dinoprostone / Q000032:analysis; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D004790:Enzyme Induction / Q000187:drug effects; D007527:Isoenzymes / Q000032:analysis / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D008297:Male; D008565:Membrane Proteins; D009690:Nucleic Acid Conformation; D020319:Oligodeoxyribonucleotides, Antisense / Q000494:pharmacology* / Q000627:therapeutic use; D009195:Peroxidase / Q000032:analysis; D011451:Prostaglandin-Endoperoxide Synthases / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000032:analysis / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley; D013379:Substrate Specificity; D013873:Thionucleotides / Q000494:pharmacology* / Q000627:therapeutic use
chemical_list: D015415:Biomarkers; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D008565:Membrane Proteins; D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; D013873:Thionucleotides; D009195:Peroxidase; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; C496513:Ptgs1 protein, rat; D015232:Dinoprostone