Polyamine synthesis inhibition induces S phase cell cycle arrest in vascular smooth muscle cells.
Polyamines are important for cell growth and proliferation and they are formed from arginine and ornithine via arginase and ornithine decarboxylase (ODC). Arginine may alternatively be metabolised to NO via NO synthase. Here we study if vascular smooth muscle cell proliferation can be reversed by polyamine synthesis inhibitors and investigate their mechanism of action. Cell proliferation was assessed in cultured vascular smooth muscle A7r5 cells and in endothelium-denuded rat arterial rings by measuring [3H]-thymidine incorporation and by cell counting. Cell cycle phase distribution was determined by flow cytometry and polyamines by HPLC. Protein expression was determined by Western blotting. The ODC inhibitor DFMO (1-10 mM) reduced polyamine concentration and attenuated proliferation in A7r5 cells and rat tail artery. DFMO accumulated cells in S phase of the cell cycle and reduced cyclin A expression. DFMO had no effect on cell viability and apoptosis as assessed by fluorescence microscopy. Polyamine concentration and cellular proliferation were not affected by the arginase inhibitor NOHA (100-200 microM) and the NO synthase inhibitor L-NAME (100 microM). Lack of effect of NOHA was reflected by absence of arginase expression. Polyamine synthesis inhibition attenuates vascular smooth muscle cell proliferation by reducing DNA synthesis and accumulation of cells in S phase, and may be a useful approach to prevent vascular smooth muscle cell proliferation in cardiovascular diseases.
Odenlund
M
M
Department of Experimental Medical Science, Division of Vascular and Airway Research, Unit of Vascular Physiology, Lund University, BMC D12, 221 84 Lund, Sweden.
Holmqvist
B
B
Baldetorp
B
B
Hellstrand
P
P
Nilsson
Bengt-Olof
BO
D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D019925:Cyclin A / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D009131:Muscle, Smooth, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009955:Ornithine Decarboxylase / Q000378:metabolism; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines / Q000037:antagonists & inhibitors* / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D016196:S Phase / Q000187:drug effects
D019925:Cyclin A; D004791:Enzyme Inhibitors; D065108:Ornithine Decarboxylase Inhibitors; D011073:Polyamines; D009955:Ornithine Decarboxylase