title: Non-steroidal anti-inflammatory drugs (NSAIDs) inhibit vascular smooth muscle cell proliferation via differential effects on the cell cycle.
abstract: Abnormal vascular smooth muscle cell (VSMC) proliferation plays an important role in the pathogenesis of both atherosclerosis and restenosis. Recent studies suggest that high-dose salicylates, in addition to inhibiting cyclooxygenase activity, exert an antiproliferative effect on VSMC growth both in-vitro and in-vivo. However, whether all non-steroidal anti-inflammatory drugs (NSAIDs) exert similar antiproliferative effects on VSMCs, and do so via a common mechanism of action, remains to be shown. In this study, we demonstrate that the NSAIDs aspirin, sodium salicylate, diclofenac, ibuprofen, indometacin and sulindac induce a dose-dependent inhibition of proliferation in rat A10 VSMCs in the absence of significant cytotoxicity. Flow cytometric analyses showed that exposure of A10 cells to diclofenac, indometacin, ibuprofen and sulindac, in the presence of the mitotic inhibitor, nocodazole, led to a significant G0/G1 arrest. In contrast, the salicylates failed to induce a significant G1 arrest since flow cytometry profiles were not significantly different from control cells. Cyclin A levels were elevated, and hyperphosphorylated p107 was present at significant levels, in salicylate-treated A10 cells, consistent with a post-G1/S block, whereas cyclin A levels were low, and hypophosphorylated p107 was the dominant form, in cells treated with other NSAIDs consistent with a G1 arrest. The ubiquitously expressed cyclin-dependent kinase (CDK) inhibitors, p21 and p27, were increased in all NSAID-treated cells. Our results suggest that diclofenac, indometacin, ibuprofen and sulindac inhibit VSMC proliferation by arresting the cell cycle in the G1 phase, whereas the growth inhibitory effect of salicylates probably affects the late S and/or G2/M phases. Irrespective of mechanism, our results suggest that NSAIDs might be of benefit in the treatment of certain vasculoproliferative disorders.
authors.affiliation: Cardiovascular Research Group, Division of Cell and Molecular Biology, School of Animal and Microbial Sciences, The University of Reading, P.O. Box 228, Whiteknights, Reading, Berkshire RG6 6AJ, UK. g.brooks@reading.ac.uk
authors.forename: Gavin
authors.initials: G
authors.lastname: Brooks
authors.forename: Xue-Mei
authors.initials: XM
authors.lastname: Yu
authors.forename: Yuequn
authors.initials: Y
authors.lastname: Wang
authors.forename: M James C
authors.initials: MJ
authors.lastname: Crabbe
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Shattock
authors.forename: Jane V
authors.initials: JV
authors.lastname: Harper
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000008:administration & dosage / Q000494:pharmacology*; D001011:Aorta / Q000166:cytology / Q000187:drug effects; D001241:Aspirin / Q000008:administration & dosage / Q000494:pharmacology; D002455:Cell Division / Q000187:drug effects*; D002460:Cell Line / Q000187:drug effects / Q000378:metabolism; D004008:Diclofenac / Q000008:administration & dosage / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005434:Flow Cytometry; D007052:Ibuprofen / Q000008:administration & dosage / Q000494:pharmacology; D007213:Indomethacin / Q000008:administration & dosage / Q000494:pharmacology; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D012980:Sodium Salicylate / Q000008:administration & dosage / Q000494:pharmacology; D013467:Sulindac / Q000008:administration & dosage / Q000494:pharmacology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D004008:Diclofenac; D013467:Sulindac; D001241:Aspirin; D012980:Sodium Salicylate; D007052:Ibuprofen; D007213:Indomethacin