Role of Nonhomologous End-Joining and Recombinational DNA Repair in Resistance to Nitrogen Mustard and DNA Crosslinking Agents

The nitrogen mustards are an important group of alkylating agents with activity against several human tumors (1–4). Many nitrogen mustard analogs are transported by carrier-mediated systems into cells and alkylate DNA, RNA, and proteins (5–7). Alkylation of DNA and, more specifically, the formation of DNA interstrand crosslinks have been considered to be responsible for their cytotoxicity (8–10). Resistance to the nitrogen mustards in murine and...