Effect of modulation of protein kinase C on the cAMP-dependent chloride conductance in T84 cells

• Published in: FEBS letters 1992-10, Vol.311 (1), p.25-28
• Main Authors: Dechecchi, Maria Cristina, Rolfini, Rossella, Tamanini, Anna, Gamberi, Chiara, Berton, Giorgio, Cabrini, Giulio
• Format: Article
• Language: English
• Subjects: 8-Bromo Cyclic Adenosine Monophosphate - pharmacology; Biological and medical sciences; Biological Transport; Cell physiology; chloride; Chloride Channels; Chloride transport; Chlorides - metabolism; Colonic Neoplasms; conductance; Cyclic AMP - pharmacology; Cystic fibrosis; Cystic Fibrosis - metabolism; Cystic Fibrosis Transmembrane Conductance Regulator; Diglycerides - pharmacology; Down-Regulation; Electric Conductivity; Fluorescence; Fluorescent Dyes; Fundamental and applied biological sciences. Psychology; Humans; Ionomycin - pharmacology; man; Membrane and intracellular transports; Membrane Proteins - drug effects; Membrane Proteins - metabolism; Molecular and cellular biology; Protein kinase A; Protein kinase C; Protein Kinase C - metabolism; Protein Kinases - metabolism; Quinolinium Compounds; RNA, Messenger - biosynthesis; role; T84 cell; Tetradecanoylphorbol Acetate - pharmacology; tumor cell lines; Tumor Cells, Cultured
• ISSN: 0014-5793; 1873-3468
• DOI: 10.1016/0014-5793(92)81358-S

The regulation of chloride conductance was investigated in the T84 human colon carcinoma cell line by the quenching of the fluorescent probe 6-methoxy- N-(3-sulfopropyl)quinolinium. The permeable cAMP analog 8-Br-cAMP (100 μ) and the calcium ionophore ionomycin (1 μM) activate a chloride conductance. A prolonged (4 h) preincubation of cells with phorbol 12-myristate 13-acetate (100 nM) or with the diacylglycerol analog 1-oleoyl-2-acetyl-glycerol (100 μM): (1) down-modulates to almost zero the protein kinase C activity in the membranes; (ii) inhibits the activation of the chloride conductance mediated by 8-Br-cAMP but not by calcium; (iii) reduces the mRNA without changing the expression of the protein product of the cystic fibrosis gene. The data suggest that PKC is essential for the activation of the cAMP-dependt chloride conductance in T84 cells.