Differential cytotoxicity to human lung normal diploid, virus-transformed and carcinoma cells by the antitumor antibiotics, auromomycin and macromomycin, and their non-protein chromophores.

With the use of three human lung cultured cell lines: normal diploid fibroblasts (WI38), their SV40-transformants (VA13) and carcinoma cells (A549), whose doubling times were similar, the cytotoxicity of the protein antitumor antibiotics, auromomycin (AUR) and macromomycin (MCR), was studied by colony formation method. The susceptibilities of the three cell lines to these antibiotics were in the order: WI38 less than VA13 less than A549. This differentiality in the cytotoxic effect was similar between AUR and MCR. The differential cytotoxic effect did not depend on cell densities of each cell line at the time of the antibiotic-treatment. Alcohol-extracted chromophores of the antibiotics also showed a similar differential cytotoxic effect, while the apo-proteins of the antibiotics showed no cytotoxicity. It is concluded that the differential cytotoxic effect of AUR and MCR to normal, transformed and carcinoma cells is attributed to the chromophore moiety and the protein moiety is not involved in this effect.