Properties of a calcitonin receptor and adenylate cyclase in BEN cells, a human cancer cell line

Abstract

A human lung cancer cell line (BEN cells) was found to have a calcitonin-responsive adenylate cyclase. Various calcitonins and synthetic analogs stimulated adenylate cyclase activity withe same relative potency as they show in lowering blood calcium in the rat. Preincubation of the cells with calcitonin, followed by washing, led to loss of subsequent adenylate cyclase response to hormone. This was a dose-dependent phenomenon. The binding of [125I]salmon calcitonin to freshly subcultured cells was studied. The ability of calcitonins and analogs to compete for binding paralleled their efficacies in stimulating adenylate cyclase. Binding was saturable, reversible, and consisted of a single class of noninteracting sites with a mean Kd of 10.75 X 10(-10) M, K of 0.93 X 10(9)/M, and mean receptor number of 2.71 X 10(4)/cell. It is not known whether the calcitonin receptor is inappropriate to the cell of origin of the tumor. The BEN cells provide a means of isolating and studying the properties of the calcitonin receptor and of evaluating the significance for the tumor of a hormone-responsive adenylate cyclase.