Cyclic 3',5'-adenosine monophosphate modulates retinal pigment epithelial cell migration in vitro

Retinal pigment epithelial (RPE) cell migration has been implicated in the pathogenesis of proliferative vitreoretinopathy (PVR). Using a modified Boyden chamber assay, we have examined the effect of cyclic nucleotides on human RPE cell migration in vitro. Dibutyryl cyclic 3',5'-adenosine monophosphate (cAMP) (10(-3) mmol/L) inhibits RPE cell random migration by 83%, fibronectin-induced chemotaxis by 61%, and platelet-derived growth factor-induced chemotaxis by 68%. Random and directed migration of RPE cells is not significantly affected by 8-bromo cyclic 3',5'-guanosine monophosphate. Agents that significantly increase intracellular levels of cAMP are also inhibitors of RPE cell migration. Though there is a fairly good correlation for most drugs for their ability to stimulate cAMP production and their ability to inhibit cell migration, it is not perfect, suggesting that some drugs may modulate migration by more than one mechanism. Timolol blocked both the isoproterenol-induced stimulation of RPE adenylate cyclase and attenuated the ability of isoproterenol to inhibit RPE migration. These data suggest that cAMP may modulate RPE cell migration in an inhibitory fashion. Elucidation of the biochemical events involved in RPE cell migration could provide information that might be useful in planning a strategy to attempt pharmacologic control of proliferative vitreoretinopathy.