title: Structural requirements for diacylglycerols to mimic tumor-promoting phobol diester action on the epidermal growth factor receptor.
abstract: The structural requirements for diacylglycerols to mimic the action of tumor-promoting phorbol diesters on the epidermal growth factor (EGF) receptor of A431 human epidermoid carcinoma cells were investigated. Five biological effects were considered: inhibition of high affinity 125I-EGF binding, change in the phosphorylation state of the EGF receptor, inhibition of the EGF-dependent tyrosine phosphorylation of the EGF receptor, inhibition of [3H]phorbol 12 beta, 13 alpha-dibutyrate binding, and stimulation of calcium- and phospholipid-dependent protein kinase (C-kinase) in vitro. A marked effect of the acyl chain length, 3-10 carbons, of symmetric sn-1,2-diacylglycerols was observed on their ability to mimic the effect of 4 beta-phorbol 12 beta-myristate 13 alpha-acetate (PMA). sn-1,2-Dipropanoylglycerol did not mimic the effects of PMA, but sn-1,2-didecanoylglycerol potently mimicked PMA action. A correlation was found between the ability of these diacylglycerols to stimulate the activity of C-kinase in vitro and to mimic the effects of PMA on the EGF receptor in intact cells. Analogues of sn-1,2-dioctanoylglycerol in which the 3' hydroxyl group was substituted with hydrogen, thio or chloro moieties were inactive when assayed for their ability to stimulate C-kinase in vitro and mimic PMA action in intact cells. We conclude that the hydroxyl group of a diacylglycerol is vital for the interaction with the phorbol diester receptor. The stringent correlation between the potency of the 11 diacylglycerol analogues tested to modulate C-kinase in vitro and to mimic PMA action in vivo provides strong evidence for the hypothesis that C-kinase plays a central role in the regulation of A431 cell EGF receptors by tumor-promoting phorbol diesters.
authors.forename: R J
authors.initials: RJ
authors.lastname: Davis
authors.forename: B R
authors.initials: BR
authors.lastname: Ganong
authors.forename: R M
authors.initials: RM
authors.lastname: Bell
authors.forename: M P
authors.initials: MP
authors.lastname: Czech
mesh_terms: D000818:Animals; D002273:Carcinogens / Q000494:pharmacology*; D002460:Cell Line; D004075:Diglycerides / Q000494:pharmacology*; D066246:ErbB Receptors; D005989:Glycerides / Q000494:pharmacology*; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000494:pharmacology*; D010704:Phorbols / Q000494:pharmacology*; D011493:Protein Kinase C; D011494:Protein Kinases / Q000378:metabolism; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013329:Structure-Activity Relationship; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
chemical_list: D002273:Carcinogens; D004075:Diglycerides; D005989:Glycerides; D010703:Phorbol Esters; D010704:Phorbols; D011956:Receptors, Cell Surface; D015240:Phorbol 12,13-Dibutyrate; D011494:Protein Kinases; D066246:ErbB Receptors; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate