title: Development and characteristics of a subline of Ehrlich ascites carcinoma cells persistently resistant to 5-fluoro-2'-deoxyuridine.
abstract: A subline of Ehrlich ascites carcinoma (EAC) cells resistant to 5-fluoro-2'-deoxy-uridine (FdUrd) was developed by continuous exposure to progressively increasing concentrations of the drug (35-75 mg/kg per day) during 15 passages through mice. Since then, the EAC cells have been retransplanted more than 80 times through drug-untreated mice and continue to be resistant. After adaptation to growth in suspension culture the drug-adapted cells were 1000 times more resistant to FdUrd in comparison with parental ones, and remained near-tetraploid with doubling time longer than in parental line. The activity of thymidine kinase was deeply depressed (100-fold) whereas that of thymidylate synthetase several-fold increased in the resistant EAC cells, both grown in vivo and in vitro.
mesh_terms: D000818:Animals; D002286:Carcinoma, Ehrlich Tumor / Q000188:drug therapy*; D002460:Cell Line; D004351:Drug Resistance; D005260:Female; D005467:Floxuridine / Q000494:pharmacology*; D006801:Humans; D008114:Liver Neoplasms, Experimental / Q000378:metabolism; D051379:Mice; D009368:Neoplasm Transplantation; D013937:Thymidine Kinase / Q000378:metabolism
chemical_list: D005467:Floxuridine; D013937:Thymidine Kinase