title: Uptake of partially thiolated DNA by ascites tumor cells.
abstract: The uptake and intracellular localization by Ehrlich ascites cells of partially [35S]thiolated homologous DNA ("antitemplate") were studied in comparison with that of the corresponding unmodified [3H]DNA, at 37 degrees and 0 degrees, under standardized conditions. For the unmodified DNA, washing the cells after incubation with 0.08 M iodoacetate (in 0.15 M NaCl) alone gave high but reproducible uptake values (23%); washing with 1 M NaCl reduced the cell-associated DNA to 12% (less than 1% at 0 degrees). It appears that 1 M NaCl is able to remove DNA reversibly bound to the cells, similarly to DNase treatment. Approximately 5% of the input [3H]DNA was taken up into the cell nuclei. Diethylaminoethyl dextran (1:1, by weight) greatly enhanced the cellular uptake of [3H]DNA. In the case of [35S]thiolated DNA, the rate as well as the extent of uptake was significantly higher (33%). Washing the cells with 1 M NaCl or treatment with DNase caused relatively small decrease in the total cell-associated [35S]thiolated DNA, the bulk of which (22% of input) was recovered in the isolated nuclei. Stimulation by diethylaminoethyl dextran of the uptake of [35S]thiolated DNA could not be established because of the insolubility of the 1:1 complex in 1 M NaCl. Excess calcium ions during incubation dramatically increased the uptake of the thiolated DNA at 37 degrees (but not at 0 degrees) by the cells (to 90 to 100%) and into the nuclear fraction (to 70% of the total [35S]DNA input). The calcium salt procedure appears to be applicable to the in vivo testing of thiolated DNA's as potential chemotherapeutic agents.
mesh_terms: D000818:Animals; D002118:Calcium / Q000494:pharmacology; D002286:Carcinoma, Ehrlich Tumor / Q000378:metabolism*; D002460:Cell Line; D002467:Cell Nucleus / Q000032:analysis; D002478:Cells, Cultured; D003637:DEAE-Dextran / Q000494:pharmacology; D004247:DNA / Q000032:analysis / Q000378:metabolism*; D003851:Deoxyribonucleases / Q000494:pharmacology; D007461:Iodoacetates / Q000494:pharmacology; D012965:Sodium Chloride / Q000494:pharmacology; D013438:Sulfhydryl Compounds / Q000378:metabolism*
chemical_list: D007461:Iodoacetates; D013438:Sulfhydryl Compounds; D012965:Sodium Chloride; D004247:DNA; D003637:DEAE-Dextran; D003851:Deoxyribonucleases; D002118:Calcium