The cytosolic phorboid receptor correlates with hormone dependency in six mammary carcinoma cell lines.
Potent, structurally different tumor promoters inhibited growth of 6 human mammary carcinoma cell lines (ROOS et al, PNAS in press). This growth inhibition was investigated by measuring the phorboid receptor binding using [3H] PDBu (4 beta-phorbol 12, 13 dibutyrate). Specific, high affinity receptors were found in all six cell lines. [3H] PDBu binding affinities were higher in the cytosolic fractions than in the corresponding intact cells (K alpha = app. 1nM vs K alpha = app. 15nM). The hormone-independent cell lines (BT-20, HBL-100 and MDA-MB-231) exhibited significantly higher levels of cytosolic [3H] PDBu receptors than the hormone-dependent cells (MCF-7, T-47-D and ZR-75-1). The subcellular distribution of the [3H] PDBu binding correlated well with the distribution of the protein kinase C activity (r = 0.95).
D001943:Breast Neoplasms / Q000378:metabolism*; D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D002460:Cell Line; D003600:Cytosol / Q000201:enzymology; D004591:Electrophoresis, Polyacrylamide Gel; D006801:Humans; D009376:Neoplasms, Hormone-Dependent / Q000378:metabolism*; D015240:Phorbol 12,13-Dibutyrate; D010703:Phorbol Esters / Q000378:metabolism; D011493:Protein Kinase C / Q000378:metabolism*; D011955:Receptors, Drug; D011971:Receptors, Immunologic / Q000378:metabolism*; D013347:Subcellular Fractions / Q000378:metabolism
D029742:Caenorhabditis elegans Proteins; D002352:Carrier Proteins; D010703:Phorbol Esters; D011955:Receptors, Drug; D011971:Receptors, Immunologic; C083141:phorbol ester binding protein; C027776:phorbol ester receptor; D015240:Phorbol 12,13-Dibutyrate; D011493:Protein Kinase C