Antiproliferative effect of L-NAME on rat vascular smooth muscle cells.
The nitric oxide synthase (NOS) inhibitor L-NAME may have growth inhibitory effects in vivo. We investigated in vitro the potential growth inhibitory effects of three different NOS inhibitors: L-NAME (1 mM), LNMMA (1 mM) and aminoguanidine (0.5 mM), on fetal bovine serum (FBS) and platelet derived growth factor (PDGF-BB)-stimulated growth in cultured vascular smooth muscle cells (VSMCs). [3H]-thymidine incorporation into rat mesenteric VSMCs was measured as an index of VSMCs proliferation (DNA synthesis) and activation of extracellular signal regulated kinase (ERK1/2), a major signaling event in cell growth, was measured by western blot assay. PDGF-BB (0-5 ng/mL) and FBS (0-5%) increased [3H]-thymidine incorporation in a dose-dependent manner up to 6-10 fold. L-NAME significantly reduced PDGF-BB (5 ng/ml) and FBS (5%) stimulated DNA synthesis by 46% and 38% respectively. The increase of [3H]-thymidine incorporation induced by PDGF-BB and FBS was unaltered by L-NMMA. In contrast, aminoguanidine induced an increase in FBS and PDGF-BB-stimulated [3H]-thymidine incorporation of 64% and 34% respectively above cells not exposed to aminoguanidine. ERK1/2 phosphorylation induced by PDGF-BB and FBS was not affected by pre-treatment with L-NAME or aminoguanidine. In conclusion, NOS inhibitors differentially influence DNA synthesis in VSMCs: L-NAME inhibits FBS and PDGF-BB-stimulated cellular proliferation whereas aminoguanidine accentuates FBS and PDGF-BB-stimulated VSMCs proliferation. These phenomena are independent of the ERK1/2 pathway. The growth inhibitory effects of L-NAME may be related to differences in properties from other NOS inhibitors, and independent of its ability to inhibit NOS.
El Mabrouk
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MRC Multidisciplinary Research Group on Hypertension, Clinical Research Institute of Montreal, Quebec, Canada.
Singh
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A
Touyz
R M
RM
Schiffrin
E L
EL
D000818:Animals; D001120:Arginine / Q000172:deficiency; D000077214:Becaplermin; D002455:Cell Division / Q000187:drug effects; D003470:Culture Media; D004247:DNA / Q000096:biosynthesis; D004347:Drug Interactions; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006131:Growth Inhibitors / Q000494:pharmacology*; D006146:Guanidines / Q000494:pharmacology; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000096:biosynthesis; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D010766:Phosphorylation / Q000187:drug effects; D010982:Platelet-Derived Growth Factor / Q000037:antagonists & inhibitors / Q000494:pharmacology; D020574:Proto-Oncogene Proteins c-sis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013936:Thymidine / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
D003470:Culture Media; D004791:Enzyme Inhibitors; D006131:Growth Inhibitors; D006146:Guanidines; D010982:Platelet-Derived Growth Factor; D020574:Proto-Oncogene Proteins c-sis; D000077214:Becaplermin; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; D004247:DNA; D001120:Arginine; D019001:Nitric Oxide Synthase; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; C004479:pimagedine; D019331:NG-Nitroarginine Methyl Ester; D013936:Thymidine