Carcinogenesis in tissue culture. 28. Comparison of various effects of a chemical carcinogen, 4-nitroquinoline I-oxide, on normal human cells and on normal mouse cells in culture.

A comparison of the effects on cultured cells of a chemical carcinogen, 4-nitroquinoline 1-oxide (4NQO), between normal human cells which were resistant to malignant transformation with 4NQO and normal mouse cells rather easily transformable was carried out. We studied the following effects of 4NQO on normal human and normal rodent cells; 1) cytotoxicity, 2) DNA, RNA and protein synthesis, 3) incorporation of 4NQO into cells and time course changes of the drug bound with macromolecular substances in cells, 4) DNA repair synthesis, and 5) chromosomal changes. Our results demonstrated that there were no differences in cytotoxicity and inhibition of cellular macromolecular syntheses between human and mouse cells. On the other hand, significant differences were noted in DNA repair synthesis and chromosomal aberrations between human and rodent cells. These differences suggest that mouse cells are easily transformed into neoplastic cells with chemical carcinogens as compared with human cells.