Inhibition of colon cancer metastasis by a 3 '- end antisense urokinase receptor mRNA in a nude mouse model

The role of urokinase-type plasminogen activator receptor (uPAR) in human c olon cancer metastasis has not been tested using an antisense approach. In our study, the HCT116 cells, with high metastatic potential were transfecte d with expression vectors containing a 3 ' or 5 ' uPAR cDNA fragment in an antisense (AS) orientation. Transfection of 4 clones was confirmed by DNA h ybridization analysis. Receptor-bound endogenous uPA activities of the clon es were reduced to 16-68% of controls. The extracellular matrix degradation by the 4 clones was decreased to 33-76%. Two of the clones, 3 ' -AS7 and 5 ' -AS, were evaluated in an in vivo assay system of experimental metastasi s using athymic mice. Pulmonary metastases were found in 63-78% mice inject ed with the parent HCT116 or control cells. In mice injected intravenously with the antisense transfected clones, 3 ' -AS7 and 5 ' -AS, however, pulmo nary metastases were found in only 19% and 9% respectively (p < 0.05), Thes e results provide direct evidence that both 3<prime> and 5 ' -AS uPAR can i nhibit colon cancer invasion and metastasis and may offer the prospect of d efining specific targets for gene therapy, (C) 2001 Wiley-Liss, Inc.