MODE OF ACTION OF ADRIAMYCIN ON HELA S-3 CELLS IN VITRO

Abstract

The effect of adriamycin on HeLa S-3 cells grown in monolayers was studied. The growth of HeLa S-3 cells was clearly inhibited at low doses of 0.05 and 0.10 meg/ml. One of the earliest changes of the cells treated with adriamycin was the rapid depression in mitotic frequency. Adriamycin caused inhibition of cell division even when added at the end of DNA synthesis phase. Adriamycin inhibited RNA synthesis more severely than DNA and protein syntheses. Moreover, the specific inhibition of RNA synthesis was observed in logarithmically growing cultures under conditions which permitted normal syntheses of DNA and protein. However, the degree of inhibition of RNA synthesis was reduced in synchronized cultures with excess thymidine. The mode of action of adriamycin is discussed.