SYNERGISTIC EFFECTS OF U46-D FLUID (DIMETHYLAMMONIUM SALT OF 2,4-D) AND CUCL2 ON CYTOTOXICITY AND DNA-REPAIR IN HUMAN FIBROBLASTS

The cytotoxicity of U46 D Fluid was tested in human fibroblasts after pretreatment with non-toxic or slightly toxic concentrations of CuCl2. While cell survival, colony-forming ability and protein synthesis were not affected by pretreatment with CuCl2, the inhibition of cell growth was enhanced as was inhibition of DNA synthesis. Synergistic effects of CuCl2 and U46 D Fluid were also detected on the induction of DNA repair measured by unscheduled DNA synthesis. While neither U46 D Fluid nor CuCl2 alone induced DNA repair, preincubation with CuCl2 followed by treatment with U46 D Fluid strongly provoked DNA repair.