COMPARATIVE EFFECTS OF APLYSIATOXIN, DEBROMOAPLYSIATOXIN, AND TELEOCIDIN ON RECEPTOR-BINDING AND PHOSPHOLIPID-METABOLISM

  • 1 January 1983
    • journal article
    • research article
    • Vol. 43  (4) , 1529-1535
Abstract
The activities of aplysiatoxin and debromoaplysiatoxin, 2 polyacetate marine algae toxins, were compared with teleocidin, a tumor-promoting indole alkaloid from Streptomyces, with resepct to inhibition of specific binding of epidermal growth factor, an phorbol-12,13-dibutyrate to their respective receptors and ability to stimulate the release of radioactivity from cells prelabeled with choline or arachidonic acid. Although these compounds have chemical structures that are quite different from the phorbol esters, both aplysiatoxin and teleocidin are essentially equipotent with the potent tumor promoter 12-O-tetradecanoylphorbol-13-acetate in all 4 assays. The fact that aplysiatoxin and teleocidin inhibit phorbol-12,13-dibutyrate-receptor binding suggests that their biological activities are mediated by binding to the same receptors utilized by the phorbol esters. Debromoaplysiatoxin, a debrominated form of aplysiatoxin, is about 10-fold weaker than aplysiatoxin in inhibiting epidermal growth factor and phorbol-12,13-dibutyrate-receptor binding, but is equipotent with aplysiatoxin in stimulating the release of lipid metabolites from the prelabeled cells. Possible heterogeneity of cellular receptors for this group of compounds is discussed.