Inhibitors of acyl-CoA:cholesterol acyltransferase. 1. Synthesis and hypocholesterolemic activity of dibenz[b,e]oxepin-11-carboxanilides.

A series of N-phenyl-6,11-dihydrodibenz[b,e]oxepin-11-carboxamides and related derivatives were prepared on the basis of structures of the reported inhibitors of acyl-CoA:cholesterol acyltransferase (ACAT). These compounds were tested for their ability to inhibit ACAT (liver microsomes from cholesterol-fed rabbits) in vitro and to decrease serum total cholesterol in cholesterol-fed golden hamsters in vivo. The structure-activity relationships in vitro were as follows. Substitution at positions 2 and 6 in the anilide resulted in potent inhibitory activity, and the potency increased with increasing size of the substituents, with maximum potency being obtained with a 2,6-diisopropyl substitution. The position of the substituent on the dibenz[b,e]oxepin ring system influenced the activity, and substitution at position 2 was critical for potent activity. The electronic effect of the substituent at position 2 does not influence activity, but bulkiness seems to be a significant factor. The lipophilicity of the compounds also plays an important role in determining ACAT inhibitory activity. Among the compounds tested, 2-bromo-N-(2,6-diisopropylphenyl)-6,11-dihydrodibenz-[b,e]++ +oxepin-11- carboxamide (33, KF17828) showed significant in vitro activity (rabbit liver microsomes IC50 = 23 nM) and the most potent in vivo activity (complete reduction in elevated serum total cholesterol levels at a dose of 10 mg/kg in hamsters).

Qualitative and quantitative characterization of Fas (CD95) expression and its role in primary human acute leukemia cells.

Fas antigen, a cell surface molecule, directly mediates apoptosis, and is expressed on a limited number of human tissues. Blood or bone marrow samples from patients with acute myelogenous leukemia (AML), acute lymphoblastic leukemia (ALL) and mixed leukemia were examined qualitatively and quantitatively for the expression of Fas as well as its function using flow cytometry and the annexin V staining method. Fas expression was flow cytometrically unimodal with heterogeneous density, and showed quantitatively characteristic features in different diseases: undetectable in mixed leukemia, faint to weak in ALL, low in M0 and M1, and variable (low to strong) in M2, M3, M4, and M5. Both the full-length and the alternatively spliced truncated mRNAs were detected constitutively even in acute leukemia cells with qualitatively negative and quantitatively faint Fas, and the band density of the former transcripts detected by RT-PCR was correlated with the level of expression of the Fas protein. Short-term culturing of freshly isolated leukemia cells gave rise to an increase of Fas density. In acute leukemia cells, the apoptosis induced by anti-Fas MoAb was compared with that induced by etoposide (a topoisomerase II inhibitor). We found that fresh ALL and AML cells were resistant to the anti-Fas IgM antibody, while etoposide could trigger apoptosis in all types of leukemia tested. The combined effects of the anti-Fas MoAb and etoposide were not always synergistic. These results suggest that Fas is a biological marker for characterizing ALL and AML cells, and provide insight into creating a new therapeutic modality using cytotoxic drugs and cytokines together with modulation of Fas.

Hepatoprotective effects of 1-[(2-thiazolin-2-yl)-amino]acetyl-4-(1,3-dithiol-2-ylidene)-2,3,4,5- tetrahydro-1H-1-benzazepin-3,5-dione hydrochloride (KF-14363) in various experimental liver injuries.

Hepatoprotective effects of KF-14363 were investigated in the following experimental models. KF-14363 inhibited the increase in serum glutamate pyruvate transaminase (GPT) dose-dependently, and a significant inhibition was noted at a dose of 30 mg/kg or more. KF-14363 significantly inhibited the D-galactosamine (D-gal)-induced increase in serum transaminase by oral administration at 250 mg/kg x 1 and 250 mg/kg x 2 doses. The D-gal-induced decrease in total protein levels was inhibited at doses of 100 mg/kg x 2 and 250 mg/kg x 2. KF-14363 (100 mg/kg or more) significantly inhibited the increase in liver triglyceride levels induced by DL-ethionine (250 mg/kg x 3). KF-14363 (300 mg/kg) significantly inhibited the D-gal plus lipopolysaccharide-induced increase in GPT. At 100 mg/kg or less, however, an inhibiting tendency was noted, which was not significant as the values varied widely. KF-14363 (100 mg/kg) significantly inhibited Propionibacterium acnes plus lipopolysaccharide-induced mortality at 7 and 8 hr, and it showed an inhibitory tendency at 24 hr. These results demonstrate that KF-14363 is a compound that has a protective effect against the damage induced in various experimental liver injury models with different mechanisms.

Effects of 1-[(2-thiazolin-2-yl)amino]acetyl-4-(1,3-dithiol 2-ylidene)-2,3,4,5-tetrahydro-1H-1-benzazepin-3,5-dione hydrochloride (KF-14363) on liver regeneration and function of hepatic mitochondria in partially hepatectomized rats.

Effects of 1-[(2-Thiazolin-2-yl)amino]acetyl-4-(1,3-dithiol 2-ylidene)-2,3,4,5-tetrahydro-1H-1-benzazepin-3,5-dione hydrochloride (KF-14363), a hepatoprotective compound, on liver regeneration, liver nucleic acid levels, mitochondrial respiration activity and hepatic energy metabolism after partial hepatectomy (OPE) in rats were studied. The liver regeneration rate was significantly increased in rats administered 100 mg/kg of KF-14363 for 6 d as compared with the control group administered vehicle. The serum glucose level in rats administered 100 mg/kg of KF-14363 measured 3 h after OPE (OPE 3 h) was significantly higher than that in rats administered vehicle (group A) and the serum insulin level in the KF-14363 group was more than double that of group A. KF-14363 also significantly increased liver nucleic acid levels in OPE rats. In mitochondrial function experiments, KF-14363 (100 mg/kg) was orally administered 2 h after OPE. Three hours after OPE (1 h after KF-14363 administration), state 3 respiration was significantly higher in the OPE 3 h + KF-14363 group than in the OPE 3 h + water group. The adenosine diphosphate/oxygen (ADP/O) ratio was also significantly higher in the OPE 22 h (22 h after OPE) + KF-14363 group than in the OPE 22 h + water group. On hepatic energy metabolism, KF-14363 increased adenosine diphosphate and triphosphate levels. Total adenine nucleotide level in the OPE 3 h + KF-14363 group was significantly higher than that in the OPE 3 h + water group. Adenylate energy charge (AEC) was slightly decreased in the OPE 3 h + water group and significantly decreased in the OPE 22 h + water group than in the corresponding sham group.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of KF-14363 on liver fibrosis in rats with chronic liver injury induced by carbon tetrachloride.

The present study examined the effects of (1-[(2-thiazolin-2-yl)amino]-acetyl-4-(1,3-dithiol-2-ylidene)-2,3, 4,5- tetrahydro-1H-1-benzazepin-3,5-dione hydrochloride (KF-14363) on liver fibrosis in rats with chronic liver injury induced by carbon tetrachloride (CCl4). Liver injury in male rats was induced by repeated administration of CCl4 at 0.5 ml/kg twice a week. The progression of liver fibrosis was checked in the 4th, 6th, 8th and 10th weeks using the relative amount of hepatic 4-hydroxy proline (4-hyp) to total proteine as an index of hepatic collagen. The relative amount of hepatic 4-hyp in these rats exceeded significantly that in rats not administered CCl4 by the 4th week. This progressed in proportion to the duration of CCl4 administration. In groups concurrently administered KF-14363 at 30 and 100 mg/kg/d from the 5th or 8th week of the CCl4 administration, the relative amount of hepatic 4-hyp was found to be lower in the 10th week than at the start of the KF-14363 administration. The inhibition of liver fibrosis was also observed histopathologically. The concurrently co-administration with CCl4 or KF-14363 at 30 and 100 mg/kg for 2 or 5 weeks inhibited the increases in serum transaminases and alkaline phosphatase induced by CCl4. The results show that KF-14363 inhibits liver fibrosis in a dose dependent fashion in rats with progressive liver injury.

Inhibitors of acyl-CoA: cholesterol acyltransferase. II. Preparation and hypocholesterolemic activity of optically active dibenz[b,e]oxepin-11-carboxanilides.

In a previous paper, we reported a novel inhibitor of acyl-CoA: cholesterol acyltransferase (ACAT), 2-bromo-N-(2,6-diisopropylphenyl)-6,11- dihydrodibenz[b,e]oxepin-11-carboxamide (1). In this work, we prepared both enantiomers and tested them for ability to inhibit ACAT (liver microsomes from cholesterol-fed rabbits) in vitro and to decrease serum total cholesterol in cholesterol-fed golden hamsters in vivo. The precursor carboxylic acid 4 was optically resolved with cinchonidine. The obtained (-)- and (+)-4 were converted to (-)- and (+)-1 without racemization, respectively. The enantiomer (-)-1 showed potent ACAT inhibitory activity in vitro with an IC50 value of 8 nM and was approximately 10-fold more active than (+)-1. Furthermore, (-)-1 showed strong hypocholesterolemic activity in vivo, whereas (+)-1 was inactive. A molecular modeling study showed that the difference of ACAT inhibitory activity between the enantiomers was derived from the spatial alignment of the bromine. Compound (-)-1 was selected for further evaluation as KW-3033.