DIFFERENTIAL SENSITIVITIES TO A CHEMICAL CARCINOGEN (4-NITROQUINOLINE N-OXIDE) IN MAMMALIAN CELL LINES IN VITRO

By comparing the sensitivity to a potent carcinogen, 4-NQO on colony-forming ability among three established cell lines in vitro, we have found that porcine kidney stable (PS) cells are more resistant to 4-NQO than the mouse L cells and Ehrlich ascites tumor cells, and mouse L cells are the most sensitive to 4-NQO. However, there are no differences in the incorporation rate of 3H-4-NQO into cells among the 3 cell lines. In a previous study, we have shown that Ehrlich ascites tumor cells were more resistant to UV than the other 2 cell lines, and PS cells were the most sensitive to UV. These results seem to indicate that the effect of UV on cells differs from that of 4-NQO, and also the reactivation process of UV-induced damage differs from that of 4-NQO-induced damage if any. It may be suspected that the difference in the reduction activity to the highly carcinogenic but less cytotoxic intermediate, 4-HAQO from 4-NQO in each cell line, causes differences in sensitivity to 4-NQO among the 3 cell lines. © 1969.