Germanium prevents pulmonary metastasis of Lewis lung cancer. - GreenMedInfo Summary

The pulmonary metastasis of Lewis lung carcinoma was strongly blocked by daily intraperitoneal (i.p.) treatment with 0.5 mg of PCAGeS/kg/day for 7 days after tumor implantation. The metastasis-preventive activity of PCAGeS was markedly reduced when mice were treated with carrageenan, a macrophage blocker. On the other hand, treatment with antiasialo GM1 antiserum did not significantly affect the percentage of inhibition of metastasis by the compound. These results suggest that macrophages rather than natural killer (NK) cells play an important role in the suppression of metastasis by PCAGeS. PCAGeS induced tumoristatic and tumoricidal activities in the peritoneal macrophages of mice by oral administration. The activity of NK cells was also augmented by i.p. treatment with the compound. These results suggest that PCAGeS is a useful substance for preventing pulmonary metastasis.