Phenylthioalkylamines in experimental tumor treatment in mice.

Two phenylthioalkylamines, phenylthioethylamine (PTEA) and phenylthiopropylamine (PTPA), were prepared and tested for cytotoxicity in vitro and as antitumor agents in (C57BL X DBA/2)F1 (BDF1) mice. Low concentrations of PTEA (median effective concentrations of 8.0, 12.0, and 1.3 micrograms PTEA/ml) inhibited the growth of P388 murine lymphoma, L1210 leukemia, and B16 melanoma cells in culture. PTPA was more effective; concentrations of 0.80, 0.56, and 0.35 micrograms PTPA/ml inhibited the growth of P388, L1210, and B16 in vitro by 50%. PTEA and PTPA treatment increased survival times in BDF1 mice bearing the P388 lymphoma, L1210 leukemia, B16 melanoma, and Lewis lung tumors. Multiple daily administrations of the test compounds were more effective than single daily injections in increasing the life-span in mice bearing the P388 lymphoma and B16 melanoma. Both PTEA and PTPA inhibited the enzyme copper-zinc superoxide dismutase.