Effects of aspirin on arylamine N -acetyltransferase activity and DNA adducts in human bladder tumour cells.

Aspirin (acetylsalicylic acid) was used to determine the inhibition of arylamine N-acetyltransferase (NAT) activity and DNA adduct formation in a human bladder tumour cell line (T24). The activity of NAT was measured by high-performance liquid chromatography, assaying for the amounts of N-acetyl-2-aminofluorene and N-acetyl-p-aminobenzoic acid and remaining 2-aminofluorene and p-aminobenzoic acid. Two assay systems were used: one with cytosol and the other with intact cells. High-performance liquid chromatography was also used to analyse for the 2-aminofluorene-DNA adducts. Intact bladder tumour cells were used. The results demonstrated that NAT activity and 2-aminofluorene-DNA adduct formation in human bladder tumour cells were inhibited by acetylsalicylic acid in a dose-dependent manner. The effects of acetylsalicylic acid on the values of the apparent K(m) and V(max) were also determined in both examined systems. The data also indicated that acetylsalicylic acid decreased the apparent values of K(m) and V(max) from human bladder tumour cells in both cytosol and intact cells.