Pertussis toxin inhibits stimulated motility independently of the adenylate cyclase pathway in human melanoma cells.

The human melanoma cell line, A2058, has previously been shown to respond to an autocrine motility factor (AMF). We have studied biochemical pathways that may be involved in the generation of such a motile response. Pertussis toxin (PT) caused a profound, rapid decrease in stimulated motility that was both dose and time-dependent. Preincubation of cells for 2 hr with as little as 1 ng/ml of PT significantly inhibited motility. A concentration of PT (0.5 microgram/ml) that completely eliminated migration after a 30 min. preincubation had a markedly reduced effect when added 1 hr after the start of the assay. In contrast, agents which selectively modulate or have a role in the adenylate cyclase pathway, e.g., cholera toxin, forskolin, the cAMP analogue 8-bromoadenosine 3':5'-cyclic monophosphate and the cyclase inhibitor 2',5'-dideoxyadenosine, all had negligible effect upon motility. These data are consistent with the presence of a receptor coupled to a PT sensitive G protein initiating motility independently of the adenylate cyclase system.