Epidermal growth factor-induced increases in inositol trisphosphates, inositol tetrakisphosphates, and cytosolic Ca2+ in a human hepatocellular carcinoma-derived cell line.
A human hepatocellular carcinoma-derived cell line, PLC/PRF/5, was examined for its ability to respond to epidermal growth factor (EGF) exposure with increased phosphatidylinositol 4,5-bisphosphate hydrolysis. Upon addition of EGF (25 ng/ml), a rapid (10-15 s) but transient increase in Ins(1,4,5)P3 levels and large, prolonged (2 min) increases in Ins(1,3,4,5)P4 and Ins(1,3,4)P3 levels were detected. Increases in cytosolic Ca2+ were observed after a 10 to 20 s lag, reaching peak value at 1 min, and remaining elevated for 10 min. The initial burst of cytosolic Ca2+ occurred in the absence of extracellular Ca2+ and probably reflects mobilization of intracellular Ca2+ stores. In cells pretreated with EGTA, the sustained component of the Ca2+ response was not observed. Comparison of the inositol phosphate and Ca2+ responses of PLC/PRF/5 cells to responses reported in other cell types indicates that this cell line is a good model for EGF action in liver.
Gilligan
A
A
Wistar Institute of Anatomy and Biology, Philadelphia, PA 19104.
Prentki
M
M
Glennon
C
C
Knowles
B B
BB
D002118:Calcium / Q000378:metabolism*; D006528:Carcinoma, Hepatocellular / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D003600:Cytosol / Q000378:metabolism; D004533:Egtazic Acid / Q000494:pharmacology; D004815:Epidermal Growth Factor / Q000494:pharmacology*; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate; D007295:Inositol Phosphates / Q000096:biosynthesis*; D008113:Liver Neoplasms / Q000378:metabolism*; D013403:Sugar Phosphates / Q000096:biosynthesis*; D014407:Tumor Cells, Cultured
D007295:Inositol Phosphates; D013403:Sugar Phosphates; C081655:inositol-1,3,4,5-tetrakisphosphate; D004533:Egtazic Acid; D004815:Epidermal Growth Factor; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium