Inhibition of haematogenous metastasis of colon cancer in mice by a selective COX-2 inhibitor, JTE-522

It is proposed that non-steroidal anti-inflammatory drugs (NSAIDs) reduce colorectal tumorigenesis by inhibition of cyclooxygenase (COX). COX is a key enzyme in the conversion of arachidonic acid to prostaglandins and two isoforms of COX have been characterized, COX-1 and COX-2. Multiple studies have shown that COX-2 is expressed at high levels in colorectal tumours and play a role in colorectal tumorigenesis. Recently it has been reported that selective inhibition of COX-2 inhibits colon cancer cell growth. In this study we investigated the effect of a selective COX-2 inhibitor (JTE-522) on haematogenous metastasis of colon cancer. For this purpose, we selected a murine colon cancer cell line, colon-26, that constitutively expresses the COX-2 protein. The subclone P expressed a high level of COX-2 and the subclone 5 expressed a low level. The colon-26 subclones were injected into the tail vein of BALB/c mice. JTE-522 was given intraperitoneally every day from the day prior to cancer cell injection, and the mice were sacrificed 16 days after cell injection. Lung metastases were compared between groups with and without JTE-522. In the mice injected with subclone P, the number of lung metastatic nodules was significantly reduced in the treated group. However, in the mice injected with subclone 5, there was little difference between the control and the treated groups. These results indicate that there may be a direct link between inhibition of haematogenous metastasis of colon cancer and selective inhibition of COX-2, and that selective COX-2 inhibitors may be a novel class of therapeutic agents not only for colorectal tumorigenesis but also for haematogenous metastasis of colon cancer. © 1999 Cancer Research Campaig

Stearoyl-CoA desaturase inhibition blocks formation of hepatitis C virus-induced specialized membranes

Hepatitis C virus (HCV) replication is dependent on the formation of specialized membrane structures; however, the host factor requirements for the formation of these HCV complexes remain unclear. Herein, we demonstrate that inhibition of stearoyl-CoA desaturase 1 (SCD-1) halts the biosynthesis of unsaturated fatty acids, such as oleic acid, and negatively modulates HCV replication. Unsaturated fatty acids play key roles in membrane curvature and fluidity. Mechanistically, we demonstrate that SCD-1 inhibition disrupts the integrity of membranous HCV replication complexes and renders HCV RNA susceptible to nuclease-mediated degradation. Our work establishes a novel function for unsaturated fatty acids in HCV replication.Peer reviewed: YesNRC publication: Ye