Antisense-mediated suppression of human heparanase gene expression inhibits plural dissemination of human cancer cells

Heparan sulfate proteoglycans is a major component of the cell surface and extracellular matrix and functions as a barrier against cationic molecules and macromolecules. Heparanase is an endoglucuronidase capable of specifically degrading heparan sulfate, and its activity is associated with the metastatic potential of tumor cells. To inhibit human heparanase expression in human cancer cells, we constructed an adenoviral vector carrying a full-length human heparanase cDNA in an antisense orientation (Ad-AS/hep). Increased heparanase expression in T.Tn human esophageal cancer cells and A549 human lung cancer cells after infection with an adenovirus vector expressing the human heparanase gene (Ad-S/hep) was specifically inhibited by simultaneous infection with Ad-AS/hep in a dose-dependent manner. A modified Boyden chamber assay demonstrated that infection with Ad-AS/hep significantly inhibited in vitro invasion of A549 cells after Ad-S/hep infection. Moreover, intrathoracic administration of Ad-AS/hep reduced the number and size of heparanase-expressing A549 tumors implanted intrathoracically into BALB/c-nu/nu mice. Our results suggest that heparanase contributes to the invasive phenotype of tumor cells, and that antisense-mediated inhibition of heparanase activity may be efficacious in the prevention of pleural dissemination.