In vitro studies on macromomycin (NSC-170105): effects on cultured TA3Ha and L1210 cells

TA3Ha and L1210 cells are prevented from further division for 24 to 72 h by a single addition of 1 to 2 μg/ml of macromomycin (MCR) to the culture medium. At this cytostatic concentration the cells remained viable and reproductive capacity could be restored by removal of the MCR by brief treatment of the cells with trypsin. Cells did not recover their ability to divide by simple resuspension in fresh medium. A large percentage of the treated population had twice the cell volume and many giant cells were found. Evidence is presented which indicates that DNA synthesis is not blocked at cytostatic concentrations of MCR.