Studies on antitumor activity of prumycin. III. Mode of action of prumycin on HeLa S-3 cells.

The mode of action of prumycin was investigated using synchronized and asynchronous cultured HeLa S-3 cells. Prumycin inhibited significantly the growth of HeLa S-3 cells at the concentration over 5 mcg/ml. DNA synthesis as well as protein synthesis was strongly inhibited at the concentration of 10 mcg/ml of prumycin, but RNA synthesis was not inhibited by the same concentration. Prumycin did not block the transition of the cells from M phase to G1 phase, however, G2 phase cells were blocked clearly by this antibiotic.