U18666A inhibits intracellular cholesterol transport and neurotransmitter release in human neuroblastoma cells

• Published in: Neurochemical research Vol. 24; no. 1; pp. 69 - 77
• Main Authors: SPARROW, S. M, CARTER, J. M, RIDGWAY, N. D, COOK, H. W, BYERS, D. M
• Format: Journal Article
• Language: English
• Published: New York, NY Springer 1999; Springer Nature B.V
• Subjects: Androstenes - pharmacology; Anticholesteremic Agents - pharmacology; Biological and medical sciences; Biological Transport - drug effects; Calcimycin - pharmacology; Calcium Channels - physiology; Cell physiology; Cholesterol - metabolism; Culture Media; Down-Regulation; Fundamental and applied biological sciences. Psychology; Humans; Hydroxycholesterols - pharmacology; Kinetics; Lysosomes - drug effects; Lysosomes - metabolism; Membrane and intracellular transports; Molecular and cellular biology; Neuroblastoma - metabolism; Norepinephrine - metabolism; Potassium - pharmacology; Receptors, LDL - drug effects; Receptors, LDL - metabolism; Sphingomyelin Phosphodiesterase - pharmacology; Staphylococcus aureus - enzymology; Tumor Cells, Cultured; Human; Intracellular transport; Cell line; Neurotransmitter; Lipids; Norepinephrine; Niemann Pick disease; Neuroblastoma; Catecholamine; In vitro; Cholesterol; Release
• ISSN: 0364-3190; 1573-6903
• DOI: 10.1023/A:1020932130753

To determine if neurochemical function might be impaired in cell models with altered cholesterol balance, we studied the effects of U18666A (3-beta-[(2-diethyl-amino)ethoxy]androst-5-en-17-one) on intracellular cholesterol metabolism in three human neuroblastoma cell lines (SK-N-SH, SK-N-MC, and SH-SY5Y). U18666A (< or =0.2 microg/ml) completely inhibited low density lipoprotein (LDL)-stimulated cholesterol esterification in SK-N-SH cells, while cholesterol esterification stimulated by 25-hydroxycholesterol or bacterial sphingomyelinase was unaffected or partially inhibited, respectively. U18666A also blocked LDL-stimulated downregulation of LDL receptor and caused lysosomal accumulation of cholesterol as measured by filipin staining. U18666A treatment for 18 h resulted in 70% inhibition of K+-evoked norepinephrine release in phorbol ester-differentiated SH-SY5Y cells, while release stimulated by the calcium ionophore A23187 was only slightly affected. These results suggest that U 18666A may preferentially block a voltage-regulated Ca2+ channel involved in norepinephrine release and that alterations in neurotransmitter secretion might be a feature of disorders such as Niemann-Pick Type C, in which intracellular cholesterol transport and distribution are impaired.