Cyclooxygenase-2 overexpression and tumor formation are blocked by sulindac in a murine model of familial adenomatous polyposis.

TitleCyclooxygenase-2 overexpression and tumor formation are blocked by sulindac in a murine model of familial adenomatous polyposis.
Publication TypeJournal Article
Year of Publication1996
AuthorsBoolbol SK, Dannenberg AJ, Chadburn A, Martucci C, Guo XJ, Ramonetti JT, Abreu-Goris M, Newmark HL, Lipkin ML, DeCosse JJ, Bertagnolli MM
JournalCancer Res
Date Published1996 Jun 01
KeywordsAdenomatous Polyposis Coli, Animals, Apoptosis, Base Sequence, Cyclooxygenase 2, Cyclooxygenase 2 Inhibitors, Cyclooxygenase Inhibitors, Cytokines, DNA Primers, Epithelial Cells, Female, Gene Expression, Intestinal Mucosa, Isoenzymes, Mice, Mice, Inbred C57BL, Mice, Mutant Strains, Molecular Sequence Data, Prostaglandin-Endoperoxide Synthases, RNA, Messenger, Sulindac

Inducible cyclooxygenase (Cox-2), also known as prostaglandin H synthase 2 (PGH-2) is a key enzyme in the formation of prostaglandins and thromboxanes. Cox-2 is the product of an immediate-early gene that is expressed in response to growth factors, tumor promoters, or cytokines. Overexpression of Cox-2 is associated with both human colon cancers and suppression of apoptosis in cultured epithelia] cells, an activity that is reversed by the nonsteroidal anti-inflammatory drug, sulindac sulfide. To address the relationship between Cox-2, apoptosis, and tumor development in vivo, we studied C57BL/6J-Min/+(Min) mice, a strain containing a fully penetrant dominant mutation in the Apc gene, leading to the development of gastrointestinal adenomas by 110 days of age. Min mice were fed AIN-76A chow diet and given sulindac (0.5 +/- 0.1 mg/day) in drinking water. Control Min mice and homozygous C57BL/6J-+/+ normal littermates lacking the Apc mutation (+/+) were fed AIN-76A diet and given tap water to drink. At 110 days of age, all mice were sacrificed, and their intestinal tracts were examined. Control Min mice had 11.9 +/- 7.8 tumors per mouse compared to 0.1 +/- 0.1 tumors for sulindac-treated Min mice. As expected, +/+ littermates had no macroscopic tumors. Examination of histologically normal-appearing small bowel from Min animals revealed increased amounts of Cox-2 and prostaglandin E(2) compared to +/+ littermates. Using two different in situ techniques, terminal transferase-mediated dUTP nick end labeling and a direct immunoperoxidase method, Min animals also demonstrated a 27-47% decrease in enterocyte apoptosis compared to +/+ animals. Treatment with sulindac not only inhibited tumor formation but decreased small bowel Cox-2 and prostaglandin E(2) to baseline and restored normal levels of apoptosis. These data suggest that overexpression of Cox-2 is associated with tumorigenesis in the gastrointestinal epithelium, and that both are inhibited by sulindac administration.

Alternate JournalCancer Res
PubMed ID8653697
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