Induction of DNA repair in HeLa S3 carcinoma cells by the N-nitroso derivatives of 1-(N-L-tryptophan)-1-deoxy-D-fructose and 1-(5-hydroxytryptamino)-1-deoxy-D-fructose.

HeLa S3 cells, when incubated at 37 degrees C with the N-nitroso derivative of the Amadori compounds 1-(N-L-tryptophan)-1-deoxy-D-fructose (FRU-TRP) or 1-(5-hydroxytryptamino)-1-deoxy-D-fructose (FRU-SEROT) in the presence of a six-fold molar excess of sodium nitrite, exhibit increased intracellular DNA synthesis. Sodium nitrite alone, at identical levels, elicits a similar response, albeit to a much lesser degree. No response whatsoever is produced when the cells are incubated with the parent Amadori compounds. The observed stimulation of DNA replication is DNA repair. Two major routes are suggested by which nitrosated FRU-TRP (NO-FRU-TRP) and nitrosated FRU-SEROT (NO-FRU-SEROT) could damage intracellular DNA.