Antiproliferative effects of A02011-1, an adenylyl cyclase activator, in cultured vascular smooth muscle cells of rat.
1. The effects of A02011-1, a pyrazole derivative, on the proliferation of rat vascular smooth muscle cells (VSMCs) were examined. 2. A02011-1 (1-100 microM) concentration-dependently inhibited [3H]-thymidine incorporation into DNA in rat VSMCs that were synchronized by 48 h serum depletion and then re-stimulated by addition of foetal calf serum (FCS, 10%), platelet-derived growth factor (PDGF, 10 ng ml-1), 5-hydroxytryptamine (10 microM) or ADP (10 microM). The inhibitory effect of A02011-1 was fully reversible. However, FCS-induced [3H]-thymidine incorporation into rat endothelial cells was unaffected by A02011-1. 3. The concentration of A02011-1 necessary for inhibition of the FCS-induced proliferation was similar to that necessary for adenosine 3':5'-cyclic monophosphate (cyclic AMP) formation. Adenylyl cyclase activity was increased in A02011-1-treated VSMCs, whereas cyclic AMP-specific phosphodiesterase activity was unchanged. 4. A02011-1 was equipotent with forskolin but was more potent than 8-bromo-cyclic AMP against FCS (10%)-induced proliferation. 5. The antiproliferative action of A02011-1 was mimicked by 8-bromo-cyclic AMP, a membrane-permeable cyclic AMP analogue and was antagonized by 2',5'-dideoxyadenosine, an adenylyl cyclase inhibitor and by Rp-cyclic AMPS, a competitive inhibitor of cyclic AMP-dependent protein kinase (PKA) type I and II. 3-Isobutyl-1-methylxanthine (IBMX) caused significant potentiation of the antiproliferative activity of A02011-1. However, Rp-8-bromo-cyclic GMPS and staurosporine did not affect the antiproliferative activity of A02011-1. 6. A02011-1 still inhibited the FCS-induced DNA synthesis even when added 10-18h after restimulation of the serum-starved VSMCs with 10% FCS. Flow cytometry in synchronized cells revealed an acute blockade of FCS-inducible cell cycle progression at a point in the G,/S phase in A02011-1-treated cells. The inhibition of proliferation by A0201 1-1 was shown to be independent of cell damage,as documented by several criteria of cell viability.7. These results indicate that A0201 1-1 inhibition of VSMC proliferation was mediated by cyclic AMP and was due to a delay in the progression from the G1 into S phase of the cell cycle. A02011-1 did not cause cell toxicity and may thus hold promising potential for the prevention of atherosclerosis or vascular diseases.
Yu
S M
SM
Department of Pharmacology, Chang Gung Medical College, Kwei-San, Tao-Yuan, Taiwan.
Cheng
Z J
ZJ
Kuo
S C
SC
D000262:Adenylyl Cyclases / Q000187:drug effects*; D000818:Animals; D002455:Cell Division / Q000187:drug effects; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000096:biosynthesis; D006152:Cyclic GMP / Q000096:biosynthesis; D004789:Enzyme Activation; D008297:Male; D008934:Mitogens / Q000037:antagonists & inhibitors; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D011720:Pyrazoles / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D013268:Stimulation, Chemical; D013876:Thiophenes / Q000494:pharmacology*; D013936:Thymidine / Q000378:metabolism
C094836:A 02011-1; D008934:Mitogens; D011720:Pyrazoles; D013876:Thiophenes; D000242:Cyclic AMP; D000262:Adenylyl Cyclases; D006152:Cyclic GMP; D013936:Thymidine