Transformation of human ciliary epithelial cells by simian virus 40: Induction of cell proliferation and retention of β₂-adrenergic receptors

Ciliary epithelial cells derived from human eye were successfully propagated through many generations after transformation with simian virus 40. The cell clone 8-SVHCE was isolated and characterized by immunoprecipitation and pharmacological studies that demonstrated the presence of several functional properties observed in the parent cells of this tissue. Immunoprecipitation revealed the presence of large tumor (T) antigen, and Southern blot analysis showed the incorporation of viral DNA into high molecular weight ciliary epithelial cell DNA. The presence of β-adrenergic receptors was demonstrated by direct binding of a radiolabeled antagonist, [¹²⁵I]iodopindolol, to membrane preparations of 8-SVHCE cells (K(d) = 41.8 pM and B(max) = 67.1 fmol/mg of protein). Competition experiments with [¹²⁵I]iodopindolol and selective drugs suggested that the receptors are of the β₂-adrenergic subtype. Studies of catecholamine-stimulated cellular cAMP production and of isoproterenol-dependent protein phosphorylation of vimentin in 8-SVHCE indicated the functional conservation of β-adrenergic receptor-mediated processes that are thought to be important in the regulation of aqueous humor production by the ciliary epithelium in vivo.