Inhibitory effects of mofezolac, a cyclooxygenase-1 selective inhibitor, on intestinal carcinogenesis.
Cyclooxygenase (COX)-2, one enzyme isoform responsible for producing prostanoids from arachidonic acid, contributes to colon carcinogenesis. Recently, genetic disruption of COX-1, the other isoform, was shown to decrease the number of intestinal polyps and prostaglandin E(2) levels in intestinal mucosa, like the case with COX-2 gene disruption, in Min mice. We therefore investigated whether a COX-1 selective inhibitor, mofezolac, suppresses intestinal carcinogenesis in rodents. F344 male rats, receiving azoxymethane (AOM, 15 mg/kg body wt) s.c. injections at 5 and 6 weeks of age, were fed a diet containing 600 or 1200 p.p.m. mofezolac for 4 weeks. The number of aberrant crypt foci (ACFs) per rat and the bromodeoxyuridine labeling index of the crypt epithelium were dose-dependently decreased by administration of mofezolac, the value for the former at 1200 p.p.m. being 60% of control value. When Apc gene knockout mice (APC1309 mice) were given 600 or 1200 p.p.m. mofezolac in their diet for 8 weeks, the numbers of intestinal polyps were also dose-dependently decreased, with reduction to 59% of that in the control diet group at the higher dose. Nimesulide, a COX-2 selective inhibitor used as positive control, showed similar suppressive effects on the development of ACFs in AOM-treated rats and polyps in Apc gene knockout mice. The data indicate that both COX-1 and COX-2 can contribute to intestinal tumorigenesis.
Cancer Prevention Division, National Cancer Center Research Institute, 1-1 Tsukiji 5-chome, Chuo-ku, Tokyo 104-0045, Japan.
Tomohiro
T
Kitamura
Toshihiko
T
Kawamori
Naoaki
N
Uchiya
Masaki
M
Itoh
Tetsuo
T
Noda
Mamoru
M
Matsuura
Takashi
T
Sugimura
Keiji
K
Wakabayashi
D000818:Animals; D000970:Antineoplastic Agents / Q000627:therapeutic use*; D001397:Azoxymethane; D015197:Carcinogenicity Tests; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors / Q000627:therapeutic use*; D004195:Disease Models, Animal; D005260:Female; D017491:Genes, APC / Q000502:physiology; D007414:Intestinal Neoplasms / Q000139:chemically induced / Q000517:prevention & control*; D007527:Isoenzymes / Q000037:antagonists & inhibitors*; D007555:Isoxazoles / Q000627:therapeutic use*; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D018345:Mice, Knockout; D011451:Prostaglandin-Endoperoxide Synthases; D051381:Rats; D011916:Rats, Inbred F344; D013449:Sulfonamides / Q000627:therapeutic use
D000970:Antineoplastic Agents; D052246:Cyclooxygenase 2 Inhibitors; D016861:Cyclooxygenase Inhibitors; D007527:Isoenzymes; D007555:Isoxazoles; D008565:Membrane Proteins; D013449:Sulfonamides; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; D011451:Prostaglandin-Endoperoxide Synthases; C496512:Ptgs1 protein, mouse; C496513:Ptgs1 protein, rat; D001397:Azoxymethane; C054999:mofezolac; C012655:nimesulide