Yukimasa Azuma, Takashi Kawasaki, Katsutoshi Ohno, Jiro Seto, Toshihiro
Yamada, Masahiro Yamasaki and Yoichi Nobuhara
Central Research Institute, Nissin Food Products Co., Ltd., 2247, Noji,
Kusatsu, Shiga 525-0055, Japan
Abstract: We studied the effect of NTE-122 (trans-1,4-bis[[1-cyclohexyl-3-
(4-dimethylamino phenyl)ureido]methyl]cyclohexane), a novel acyl-CoA:cholesterol
acyltransferase (ACAT) inhibitor, on intracellular cholesterol esterification
and the secretion of apolipoprotein B100 (apoB)-containing lipoprotein and
bile acids in the human hepatoma cell line HepG2. NTE-122 markably inhibited
[3H]oleate incorporation into cholesteryl esters in HepG2 cells
incubated with 5 microg/ml 25-hydroxycholesterol as a stimulus for ACAT
(IC50=6.0 nM). On the other hand, NTE-122 did not affect [3H]oleate
incorporation into triglycerides and phospholipids and [14C]acetate
incorporation into cholesterol. The stimulation of ACAT by 25-hydroxycholesterol
caused significant increases in the secretion of radiolabeled cholesteryl
esters, radiolabeled triglycerides and apoB mass. NTE-122 pronouncedly inhibited
the secretion of radiolabeled cholesteryl esters in proportion to the inhibition
of cellular cholesterol esterification, and it significantly reduced the
secretion of radiolabeled triglycerides and apoB mass in HepG2 cells incubated
with 25-hydroxycholesterol. Furthermore, NTE-122 increased the secretion
of bile acids synthesized from [14C]cholesterol. These results
suggest that NTE-122 is capable of exhibiting anti-hyperlipidemic effects
by reducing both the cholesterol content and the amount of secreted very
low-density lipoprotein and enhancing the excretion of bile acid from the
liver.
Keywords: NTE-122, Acyl-CoA:cholesterol acyltransferase (ACAT) inhibitor,
HepG2 cell, Apolipoprotein B-containing lipoprotein secretion, Bile acid
secretion