Toxicity and antitumor activity of hexamethylmelamine and its N-demethylated metabolites in mice with transplantable tumors
Lake, L.M.; Grunden, E.E.; Johnson, B.M.
Cancer Research 35(10): 2858-2863
1975
ISSN/ISBN: 0008-5472 PMID: 808270 Document Number: 94125
N-Demethylated metabolites of the antineoplastic agent hexamethylmelamine were synthesized, and their toxicities and antitumor activities were determined in vivo. Determinations of the lethal dose for 10% of the male C57BL X DBA/2 F1 (hereafter called BD2F1) mice showed hexamethylmelamine toxicity to be decreased by N-demethylation; the metabolites showed a direct relationship between potency (mmoles/kg/day) and number of methyl groups present. In BD2F1 mice bearing Sarcoma 180 or Lewis lung carcinoma, the antitumor activities of the methylmelamines decreased with a reduction in number of methyl groups, but were similar at equitoxic levels. Results were similar in L1210 leukemic mice treated with lethal dose levels of the metabolites for 10% of the mice when mean survival times were measured. The therapeutic equality produced with equitoxic levels, together with the ineffectiveness of melamine, suggested that the presence of a methyl group, rather than the number, was the determining factor in the antitumor activity of the methylmelamines.