Norma Adragna (Committee Member), Thomas Brown (Committee Member), David Cool (Committee Member), Peter Lauf (Advisor)
Master of Science (MS)
Protein kinase inhibition by staurosporine causes apoptotic volume decrease involving potassium (K) channels in immortalized human B3 lens epithelial cells (LECs). Here, the effect of two pro-apoptotic protein kinase C (PKC) inhibitors [12-O-tetradecanoyl-phorbol-13-acetate (TPA) and chelerythrine (CET)] were studied on membrane K transport in a fetal human LEC line (FHL124) by western blotting, immunofluorescence, ion flux, ATP, apoptosis, and biotinylation assays. Long term TPA exposure (0-6 h) inhibited 75% of Na-K-2Cl cotransport (NKCC). In contrast, short term (0-20 min) exposure to 50 μM CET reduced Na/K pump and NKCC by >90% and >70%, respectively, without retrieval from the membrane into the cytosol, loss of ATP and early signs of apoptosis. CET (10-30 μM) decreased cell K by 33%. Results suggest PKC modulation through the use of pro-apoptotic agents caused major early membrane changes independently affecting K channels, the Na/K pump and NKCC function, prior to rise of any significant apoptosis.
Department or Program
Department of Pharmacology and Toxicology
Year Degree Awarded
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