Cytotoxic activity of methylene bis-nucleotides

New facts relating to the mechanism of cytotoxic and antitumor activity of formaldehyde-treated RNA and its hydrolysates have been revealed. Synthetic methylene bis-nucleotides and, in particular, methylene bis-nucleosides have a cytotoxic effect on cultured human adenocarcinoma cells (line HCCL). The cytotoxic effect of methylene bis-derivatives of the guanine series was most pronounced. In addition, methylene bis-nucleotides were depbosphorylated in the cell culture medium. Chromosome aberrations were induced by alkaline hydrolysate of dialyzed formaldehyde-treated RNA in which 39% of purine nucleotdies were modified to methylene bis-derivatives.