Figure 5

Suppression of egr-1 or the VDUP-1 gene expression did not affect the growth of T24 cells treated with genistein. Since the expression of the egr-1 and VDUP-1 genes was dramatically induced by genistein in T24 cells, their role in reversing the inhibitory effect of the drug was investigated. The effect of blocking gene expression by the antisense and their control ODNs was tested with Western blotting, and expected results were obtained (data not shown). The result of cell proliferation assays revealed that, regardless of the presence and absence of 50 μ M genistein, treatment of the T24 cell line with the antisense ODN for either gene (up to 10 μ M), did not alter the cell growth pattern, suggesting that these proteins are not involved in the drug resistance mechanism. In these experiments, the nucleotide sequence-scrambled egr-1 ODN, which had been characterised previously (Sells et al, 1995) and the sense-strand ODN for the VDUP-1 genes, which is according to the reported gene sequence (Han et al, 2003), were used as controls. The result demonstrated that they did not have any influence on the growth of T24 cells even when genistein was added. The symbols used here are: cells without any treatment, □; and cells treated with 0.5% DMSO, ▪; 50 μ M genistein, ; the control ODN for egr-1 or the VDUP-1 gene, ▨; the control ODN for egr-1 or the VDUP-1 gene supplemented with 50 μ M genistein, ; the antisense ODN for either one gene, ⍁; and the antisense ODN for either one gene plus genistein, .