title: Polyamine starvation prolongs the S and G2 phases of polyamine-dependent (arginase-deficient) CHO cells.
abstract: This study analyzes the effects of polyamine starvation on cell cycle traverse of an arginase-deficient CHO cell variant (CHO-A7). These cells grow well in serum-free medium, provided that it contains ornithine or polyamines or both. In the absence of ornithine or polyamines or both, the CHO-A7 cells develop severe polyamine deficiency and, as a consequence, grow more slowly. When grown to a stationary phase in the presence of ornithine or putrescine or both, the CHO-A7 cells became arrested in G0/early G1. However, when starved for ornithine and polyamines, they accumulated in the S and G2 phases. Ornithine and polyamine starvation of CHO-A7 cells causes an increase in ornithine decarboxylase activity. When this increase was prevented by treatment with DL-alpha-difluoromethylornithine, an enzyme-activated irreversible inhibitor of ornithine decarboxylase, growth was further suppressed, and a greater fraction of cells were found in the S and G2 phases of the cell cycle.
mesh_terms: D000818:Animals; D002453:Cell Cycle / Q000187:drug effects; D002460:Cell Line; D006224:Cricetinae; D003412:Cricetulus; D004261:DNA Replication / Q000187:drug effects; D005260:Female; D020162:Hyperargininemia; D007399:Interphase / Q000187:drug effects*; D007700:Kinetics; D009154:Mutation; D009955:Ornithine Decarboxylase / Q000378:metabolism; D010053:Ovary; D011073:Polyamines / Q000378:metabolism / Q000494:pharmacology*
chemical_list: D011073:Polyamines; D009955:Ornithine Decarboxylase