[Antitumor effect of cepharanthin--mechanism of the antimetastatic effect on Lewis lung carcinoma (3LL)].

The antitumor activity of cepharanthin against Lewis lung carcinoma (3LL) primary tumor and its pulmonary metastases was evaluated. Oral administration of cepharanthin to tumor-bearing mice at a daily dose of 5 mg/kg resulted in inhibition of 3LL primary tumor growth, preferential suppression of pulmonary metastases, and prolongation of survival time. The antimetastatic effect was not observed when tumor-bearing mice were treated with some blockers of immunocompetent cells, e.g. carrageenan or monoclonal anti-Thy 1.2 antibody. In ex vivo experiments, cepharanthin was also shown to augment the activities of murine alveolar macrophages and splenic natural killer (NK) cells. These results suggest that the antitumor or antimetastatic effect of cepharanthin might be expressed through host defense mechanisms, including macrophages, T lymphocytes and/or NK cells.