Action of Polylysine on Some Ascites Tumors in Mice. ∗

Summary

Synthetic polypeptides of lysine, of glutamic acid, of valine and lysine, of leucine and lysine, and commercial protamine sulfate were tested against tetraploid Ehrlich ascites carcinoma in Swiss mice. Only the synthetic polypeptides of lysine inhibited ascites tumor development. Up to 27% of mice treated with polylysine survived for 100 days apparently free from tumor. Mice that died after 3 to 4 weeks usually did so from metastatic solid tumors or solid tumors at site of implant. Polylysine also had a marked inhibitory activity against the diploid strain of Ehrlich ascites carcinoma and TA3 ascites carcinoma in Swiss and BAFl mice, respectively. Survival time of some BAFl mice was increased to 86 days, while 10% of Swiss mice survived 100 days with no sign of tumor. On cytological analysis, mitotic arrest at prophase was found. The nucleic acid and protein content/cell remained unchanged.