Inhibition of human colon cancer cell growth by antisense oligodeoxynucleotides targeted at basic fibroblast growth factor

Background: Basic fibroblast growth factor has been shown to be mitogenic i n colon cancer cell lines. In human malignant melanoma cells, antisense oli godeoxynucleotides targeted against basic fibroblast growth factor messenge r RNA significantly inhibit cell growth. However, the efficacy of such an a ntisense oligodeoxynucleotide strategy has not been evaluated for colon can cer cells. Aim: To investigate whether basic fibroblast growth factor can stimulate th e growth of HT-29 human colon cancer cells and whether antisense oligodeoxy nucleotides can inhibit growth of these cells at baseline. Methods: Western blotting analyses were used to confirm the presence of bas ic fibroblast growth factor protein in this cell line. Cell growth was asse ssed after 2, 4 and 6 days of treatment by cell counting using the trypan b lue exclusion method. Phosphorothioate-modified oligodeoxynucleotides (10 m uM) were used, complementary to codon 60 of the basic fibroblast growth fac tor messenger RNA. Cationic liposomes (DOTAP) were used to enhance the cell ular uptake of the oligodeoxynucleotides. Results: Western blotting demonstrated the presence of basic fibroblast gro wth factor protein in this cell line. Basic fibroblast growth factor (1-40 ng/mL) dose-dependently stimulated cell growth and peak values were obtaine d at a dose of 20 ng/mL. By contrast, antisense oligodeoxynucleotide treatm ent significantly inhibited cell growth compared with the sense oligodeoxyn ucleotide-treated cells (P=0.007). This inhibition was reversed by the addi tion of basic fibroblast growth factor, 20 ng/mL. Conclusion: Treatment targeted against basic fibroblast growth factor messe nger RNA inhibits growth of HT-29 human colon cancer cells. This finding ma y provide a rationale for the therapeutic use of antisense oligodeoxynucleo tides targeted at basic fibroblast growth factor for the treatment of colon cancer.