Suppression of HUVEC tissue factor synthesis by antisense oligodeoxynucleotide.

Tissue factor (TF) is an important regulator and effector molecule of coagulation. It is primary known as a cofactor for factor VIIa-mediated triggering of blood coagulation, which proceeds in a cascade of extracellular reactions, ultimately resulting in thrombin formation. In sepsis, expression of TF by activated monocytes, macrophages and endothelial cells may lead to disseminated intravascular coagulation. Further studies have suggested that TF also plays non-haemostatic roles in blood vessel development, tumor angiogenesis, metastasis and inflammation. In the present study we examined the feasibility of inhibiting lipopolysaccharide (LPS)-induced TF expression in cultured human umbilical vein endothelial cells (HUVECs) using a modified phosphorothioate antisense oligodeoxynucleotide targeted to the TF mRNA. CD31 receptor-mediated endocytosis was used as a means of delivering TF antisense oligomer to HUVECs. This DNA carrier system consists of anti-CD31 antibody conjugated to the antisense. Co-exposure of HUVECs with TF antisense and LPS resulted in 54.6+/-3.2% suppression of TF activity when compared with control LPS stimulated cells. The antisense also reduced the LPS-induced TF mRNA level. Control experiments with TF sense and mismatched antisense oligomers were performed to exclude non-specific inhibitory effects. The cytotoxicity of the antisense oligomer conjugate was also evaluated. Results demonstrate that this TF antisense oligomer specifically suppressed the synthesis of biologically active endothelial TF and that antisense oligomers might represent a useful tool in the investigation of endothelial TF function/biology.

Antisense oligonucleotide therapy in cancer.

The sequencing of the human genome has highlighted some of the genes that are of importance in disease states. This has provided opportunities for the development of new therapeutics to target a wide range of human diseases. These new drugs are intended to be highly specific; antisense oligonucleotides (ONs) are one such class of new drugs. ONs are short pieces of DNA which hybridize to a specific target mRNA blocking its translation to protein, thereby inhibiting the action of the gene. Several genes known to be of importance in the regulation of apoptosis, cell growth, metastasis and angiogenesis provide a tantalizing prospect for the development of anticancer agents. The phosphorothioate antisense ONs are the current choice for antisense therapy. This article reviews the current strategies for antisense targets in cancer therapy.