Lack of toxic effects of F 12511, a novel potent inhibitor of acyl-coenzyme A: cholesterol O-acyltransferase, on human adrenocortical cells in culture

• Published in: Biochemical pharmacology 2001-02, Vol.61 (4), p.387-398
• Main Authors: Junquero, Didier, Pilon, Antoine, Carilla-Durand, Elizabeth, Patoiseau, Jean-François, Tarayre, Jean-Pierre, Torpier, Gérard, Staels, Bart, Fruchart, Jean-Charles, Colpaert, Françis C., Clavey, Véronique, Delhon, André
• Format: Article
• Language: English
• Subjects: ACAT; Adrenal cells; Adrenal Cortex Neoplasms; Adrenal Glands - drug effects; Adrenal Glands - enzymology; Adrenal ultrastructure; Anilides - pharmacology; Binding Sites; Biological and medical sciences; Biological Transport; Cell Survival - drug effects; Cholesterol - metabolism; Enzyme Inhibitors - pharmacology; F 12511; Gene Expression Regulation - drug effects; General and cellular metabolism. Vitamins; Humans; Lipid Metabolism; Lipoproteins, HDL - metabolism; Lipoproteins, LDL - metabolism; Medical sciences; Pharmacology. Drug treatments; Receptors, Lipoprotein - metabolism; Steroidogenesis; Steroids - metabolism; Sterol O-Acyltransferase - antagonists & inhibitors; Sterol O-Acyltransferase - metabolism; Tumor Cells, Cultured
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/S0006-2952(00)00555-4

Inhibition of acyl-coenzyme A: cholesterol O-acyltransferase (EC 2.3.1.26; ACAT) reduces intracellular cholesteryl esters that are substrates for steroidogenesis in adrenal cells. The adrenal side effects of ACAT inhibitors remain a key point for their development as antiatherosclerotic agents. The aim of this study was to characterize the effects of a novel and powerful ACAT inhibitor, F 12511 ( S)-2′,3′,5′-trimethyl-4′-hydroxy-α-dodecylthio-phenylacetanilide, on the NCI-H295R cell line, which has functional properties comparable to those of normal human adrenal cells. F 12511 incubated with cultured cells for 4–72 hr strongly inhibited cholesteryl oleate formation. The concentrations required to produce 50% inhibition ( ic 50 values) ranged from 20 to 50 nM; in the presence of low-density lipoproteins (LDL), this effect was paralleled by a decrease in cholesteryl ester mass and an increase in intracellular free cholesterol. At concentrations 100-fold larger than the ic 50 value for up to 48 hr, F 12511 reduced neither the basal release of cortisol and aldosterone nor the production of cortisol stimulated by forskolin. F 12511 did not modify the mRNA levels of the steroidogenic enzyme genes cytochrome P450 cholesterol side-chain cleavage (P450scc), cytochrome P450 17α-hydroxylase (P450c17), or cytochrome P450 21-hydroxylase (P450c21) or those of the LDL receptor and high-density lipoprotein scavenger receptor class B, type I (SR-BI) genes, either in the presence or absence of adenosine 3′,5′-cyclic monophosphate stimulation for 24 hr. Exposure to F 12511 at up to 3 μM for 24 or 48 hr did not result in significant change in morphological and ultrastructural characteristics; the cytoplasm contained large numbers of mitochondria with intact crystae, and the same typical features of secretory activity were observed in NCI-H295R control cells. Exposure to 3 μM of F 12511 for 96 hr also did not affect cell viability. These data demonstrate that reduction of the substrate for steroidogenesis by the ACAT inhibitor F 12511 impairs neither steroid production nor transcription of genes involved in steroidogenesis and lipoprotein uptake in the pluripotent human adrenal cell line NCI-H295R.