Alteration of the phosphorylation state of p34cdc2 kinase by the flavone L86-8275 in breast carcinoma cells : correlation with decreased H1 kinase activity

摘要: Abstract The flavone L86-8275 [(−)]cis-5,7-dihydroxy-2(2-chlorophenyl)-8-[4-(3-hydroxy-1-methyl)-piperidyl]-4H-1-benzopyran-4-one] delayed the progression of aphidicolin-synchronized MDA-468 breast carcinoma cells through S phase and prevented G2. G2-related increase in histone H1 kinase activity mediated by cyclin-dependent kinase-1 (p34cdc2 kinase). inhibited [32P]orthophosphate labeling p34cdc2 threonine tyrosine residues decreased phosphotyrosine content p34cdc2. Diminution appeared selective, as a general depletion cellular was not observed. mass L86-8275-exposed during period over which these effects occurred. [35S]Methionine or other proteins at concentrations that were effective for complete growth inhibition. We hypothesize interferes with normal cell cycle-dependent phosphorylation p34cdc2, resulting cycle arrest.