Cellular uptake and localization of fluorescent derivatives of phorbol ester tumor promoters.
The synthetic fluorescent derivatives of 12-O-tetradecanoylphorbol-13-acetate (TPA), dansyl-TPA, dansyl-TPA-20-acetate and dansyl-TPA-13-desacetate, have ID50 values in the [3H]PDBu binding assay of 2nM, 30nM and 1000nM respectively; the ID50 value of TPA is 4nM. Dansyl-TPA is also equipotent with TPA as an activator of protein kinase C(PKC) producing half maximum stimulation at 2nM. Dansyl-TPA-13-desacetate is almost as potent as dansyl-TPA, while dansyl-TPA-20-acetate is completely inactive as an activator of PKC. The cellular uptake of these fluorescent TPA derivatives tends to parallel their activity in the [3H]PDBu binding assay. Treatment of C3H 10T1/2 cells with 100nM dansyl-TPA results in intense fluorescence of the entire cytoplasm, while the nucleus is virtually devoid of fluorescence. The uptake of fluorescence is quenched by an excess of TPA. Thus, dansyl-TPA rapidly enters cells and binds to specific sites distributed throughout the cytoplasm. Presumably these sites reflect the cellular localization of phorbol ester receptors and protein kinase C.
D000818:Animals; D001667:Binding, Competitive; D002417:Cattle; D002460:Cell Line; D002642:Chick Embryo; D003593:Cytoplasm / Q000378:metabolism*; D003619:Dansyl Compounds / Q000378:metabolism*; D004789:Enzyme Activation / Q000187:drug effects; D005456:Fluorescent Dyes; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000378:metabolism; D010704:Phorbols / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D013329:Structure-Activity Relationship; D013755:Tetradecanoylphorbol Acetate / Q000031:analogs & derivatives / Q000378:metabolism* / Q000494:pharmacology
D003619:Dansyl Compounds; D005456:Fluorescent Dyes; D010703:Phorbol Esters; D010704:Phorbols; D015240:Phorbol 12,13-Dibutyrate; C043670:O-(N-dansylamino-3-tetradecanoyl)-12,O-acetyl-13-phorbol; C046620:12-O-(12(N)-dansylaminododecanoyl)phorbol 12,20-diacetate; C046621:12-O-(12-N-dansylaminododecanoyl)phorbol; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate