Reactions of N-nitrosoureas with cell membranes.

The strongly carcinogenic N-nitrosoureas react with phosphatidylethanolamine (PE) in chicken erythrocyte ghosts or rat kidney cells, while weaker carcinogens do not. The reactions proceed through carbamoylation of the amino group of PE by isocyanates generated from the agents. Many commercial isocyanates, including methyl isocyanate, react with PE similarly to the strong carcinogens, suggesting that this reaction may be involved in promotion in human cancer.