[Characteristics of anthracycline-resistant strains of P388 leukemia].

Two strains of P388 murine leukemia with acquired resistance to rubomycin (P388/rm) and its nitroxyl derivative ruboxyl (P388/rx). The rubomycin resistance has been developed by the 14th generation and ruboxyl one-by the 8th generation. The growth kinetic patterns and the cell cycle time of the parent and resistant strains were similar. An increased tumourogenicity of both resistant strains cells was found. The resistance development was accompanied by the appearance of the additional chromosome materials, namely of homogeneously staining region (P388/rx) and of double chromatin bodies (P388/rm). The partial recovery of sensitivity to rubomycin occurred during 36 generations (1 year). Simultaneously the genetic markers have been lost. The recovery of sensitivity to ruboxyl in this period was not observed. The obtained resistant strains possessed the multidrug resistance: the cross resistance of P388/rm and P388/rx to actinomycin D, Vinca alkaloids and colchicine was shown.