N-nitroso-N-methylurea

N-nitroso-N-methylurea (NMU) is a highly potent, directly-acting alkylating agent that has been widely used in experimental oncology for the induction of tumors in animals. It is a derivative of urea and is similar in structure to the carcinogenic nitrosamines found in tobacco smoke and certain foods.

Chemistry

NMU is a small, water-soluble molecule with the chemical formula C2H5N3O2. It is a yellowish, crystalline solid that is stable under normal conditions but decomposes in the presence of strong acids or bases. The molecule consists of a urea moiety with one of the hydrogen atoms replaced by a methyl group, and a nitroso group attached to the nitrogen atom.

Mechanism of action

NMU acts as an alkylating agent, transferring a methyl group to DNA bases, primarily at the O6 position of guanine. This methylation causes mispairing during DNA replication, leading to mutations that can initiate the process of carcinogenesis. NMU is particularly effective at inducing mammary tumors in rats, and is often used in studies of breast cancer.

Health effects

Exposure to NMU can have serious health effects, including cancer, mutagenesis, and teratogenesis. It is classified as a Group 2A carcinogen by the International Agency for Research on Cancer (IARC), meaning it is probably carcinogenic to humans. Protective measures should be taken when handling NMU to prevent exposure.

Use in research

NMU has been used extensively in cancer research for the induction of tumors in laboratory animals. It is particularly effective at inducing mammary tumors in rats, and has been used in studies of breast cancer. NMU-induced tumors are often used as a model for studying the mechanisms of carcinogenesis and the effects of potential anticancer drugs.

See also

• Alkylating antineoplastic agent
• Carcinogenesis
• Mutagen
• Teratogen