Effect of the radiosensitizer misonidazole and the radioprotector diethyldithiocarbamate on spontaneous metastasis formation of murine tumors.

The effect of treatment with the hypoxic cell radiosensitizer misonidazole (MISO) and the radioprotector diethyldithiocarbamate (DDC) on the formation of spontaneous lung metastases of four different spontaneously metastasizing murine tumors was investigated. The tumors were mammary carcinoma MCA-K, hepatocarcinoma HCA-1, and sarcomas SA-4020 and SA-NH. Multiple daily treatments with MISO significantly enhanced the incidence of metastases only in MCA-K. Because only MCA-K, but not the three remaining tumors, is immunogenic, the treatment with MISO may be associated with the promotion of metastasis primarily in the immunogenic tumors. Treatment of mice with DDC had no influence on metastatic spread. However, when given prior to 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU), DDC reduced BCNU-induced enhancement of HCA-1 metastases.