title: Mechanisms of the antitumoural effects of aspirin in the gastrointestinal tract.
abstract: A recent clinical study showed that after five years of taking aspirin, at doses of at least 75 mg once daily, death rates were 54% less for gastrointestinal (GI) cancers. The finding of aspirin benefit at low-doses used for cardioprevention, locates the antiplatelet effect of aspirin at the centre of its antitumour efficacy. At low-doses, aspirin acts mainly by an irreversible inactivation of platelet cyclooxygenase (COX)-1 activity. We propose that platelet activation is involved in the early stages of colorectal carcinogenesis in man through the induction of a COX-2-mediated paracrine signalling between stromal cells and epithelial cells within adenomas. In this scenario, aspirin causes a chemopreventive effect by countering platelet activation which seems to play a role in early event in GI tumourigenesis.
authors.affiliation: Department of Medicine and Aging, G. d'Annunzio University, School of Medicine, Italy.
authors.forename: Annalisa
authors.initials: A
authors.lastname: Bruno
authors.forename: Melania
authors.initials: M
authors.lastname: Dovizio
authors.forename: Stefania
authors.initials: S
authors.lastname: Tacconelli
authors.forename: Paola
authors.initials: P
authors.lastname: Patrignani
mesh_terms: D000236:Adenoma / Q000517:prevention & control; D016588:Anticarcinogenic Agents / Q000008:administration & dosage / Q000494:pharmacology*; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects; D051545:Cyclooxygenase 1 / Q000378:metabolism; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000008:administration & dosage / Q000494:pharmacology*; D005770:Gastrointestinal Neoplasms / Q000209:etiology / Q000517:prevention & control*; D041981:Gastrointestinal Tract / Q000187:drug effects; D006801:Humans; D010974:Platelet Aggregation / Q000187:drug effects / Q000502:physiology
chemical_list: D016588:Anticarcinogenic Agents; D016861:Cyclooxygenase Inhibitors; D051545:Cyclooxygenase 1; D051546:Cyclooxygenase 2; C496540:PTGS2 protein, human; D001241:Aspirin