cAMP levels in cells attached to AN69 and Cuprophan: cAMP dependence of cell aggregation and the influence of serum

We have examined the link between the aggregation or spreading of cells adh ering to substrata of differing biocompatibility and activation of the cycl ic AMP (cAMP) pathway. We compared the rate at which the Mouse Swiss 3T3 fi broblasts attached to Cuprophan (CU), AN69 and a control plastic in the pre sence and absence of foetal calf serum (FCS). Serum had no effect on the ki netics of cell attachment to CU or AN69. Cells incubated in culture medium containing 10% FCS aggregated on CU, whereas they spread on AN69 and plasti c. Aggregated cells contained significantly higher concentrations of cAMP t han cells spreading, and aggregation was prevented by treatment with micona zole, an inhibitor of adenylyl cyclase. cAMP-dependent cell aggregation occ urred on all three substrata in serum-free medium, suggesting that proteins adsorbed onto AN69 and plastic in the presence of serum helped protect the cells. Far less serum protein was adsorbed onto CU than onto AN69 or plast ic, consistent with the similar increases in cAMP in cells attached to CU w ith or without serum. (C) 1998 Elsevier Science Ltd. All rights reserved.