Surface Logix, Inc.

First-generation microsomal triglyceride transfer protein (MTP) inhibitors were designed to inhibit hepatic MTP and provide a novel treatment of dyslipidemia. Effective at lowering low-density lipoprotein-cholesterol (LDL-C), these inhibitors also elevate liver enzymes and induce hepatic steatosis in animals and humans. MTP is highly expressed in the enterocytes, lining the lumen of the jejunum, and is critical in the production of chylomicrons assembled from lipid/cholesterol and their transfer into systemic circulation. 6-(4'-Trifluoromethyl-6-methoxy-biphenyl-2-ylcarboxamido)-1,2,3,4-tetrahydroisoquinoline-2-carboxylic acid phenyl ester (SLx-4090) (IC(50) value ∼8 nM) was designed to inhibit only MTP localized to enterocytes. In Caco-2 cells SLx-4090 inhibited apolipoprotein B (IC(50) value ∼9.6 nM) but not apolipoprotein A1 secretion. Administered orally to rats SLx-4090 reduced postprandial lipids by >50% with an ED(50) value ∼7 mg/kg. SLx-4090 was not detected in the systemic or portal vein serum of the animals (lower limit of quantitation ∼5 ng/ml) after single or multiple oral doses in fasted rodents. When coadministered with tyloxapol, SLx-4090 did not inhibit the secretion of hepatic triglycerides (TG), consistent with the absence of systemic exposure. Chronic treatment with SLx-4090 in mice maintained on a high-fat diet decreased LDL-C and TG and resulted in weight loss without the elevation of liver enzymes or an increase in hepatic fat. The compound did not result in toxicity when administered to rats for 90 days at a dose of 1000 mg/kg per day. These data support the concept that the inhibition of enterocytic MTP could serve as a useful strategy in the treatment of metabolic disorders.

Inhibitors of Rho kinase (ROCK) are a relatively new class of drugs with potential benefits in oncology, neurology, and fibrotic and cardiovascular diseases. ROCK inhibitors modulate many cellular functions, some of which are similar to the pleiotropic effects of statins, suggesting additive or synergistic properties. Studies to date have used compounds that inhibit both isoforms of ROCK, ROCK1 and ROCK2. This study was designed to compare gene expression profiles of atorvastatin with the newly developed ROCK2 inhibitor SLx-2119 in primary cultures of normal human endothelial cells, smooth muscle cells, and fibroblasts. Cells were treated with each compound for 24 h, after which total RNA was isolated and genome-wide gene-expression profiles were obtained with Illumina arrays. Because of the known effect of statins on the actin cytoskeleton and on connective tissue growth factor, a prominent growth factor involved in tissue fibrosis, the effects of SLx-2119 and atorvastatin on the actin cytoskeleton and connective tissue growth factor mRNA were also examined in cultures of smooth muscle cells with a fibrotic phenotype, isolated from biopsies of human intestine with radiation-induced fibrosis. Although SLx-2119 and atorvastatin affected expression of genes belonging to the same biological processes, individual genes were mostly different, consistent with synergistic or additive properties. Both SLx-2119 and atorvastatin reduced connective tissue growth factor mRNA and remodeled the actin cytoskeleton in fibrosis-derived smooth muscle cells, suggesting that both compounds have antifibrotic properties. These results form the basis for further studies to assess the possible therapeutic benefit of combined treatments.