RESUMO
Aim To explore the effect of 4-amino-2-trifluoromethyl-phenyl retinate(ATPR)on proliferation,differentiation activity in K562 cell line,and to research the mechanisms.Methods Cell proliferation was assessed by MTT assay.Cell differentiation index was analyzed by NBT reduction test.Morphologic changes were observed by Wright's staining in the light microscope. Cell cycle was determined by FCM.The mRNA expression of Cyclin D1,Cyclin E,CDK2,CDK4,CDK6,P21cip1,P27kip1,P57kip2,PCNA mRNA were detected by RT-PCR.While the protein expression of cyclin D1 and CDK4 was detected by Western blot.Results The growth of K562 cells was inhibited in a dose-dependent manner.NBT reduction test indicated that the ATPR could induce differentiation of K562 cells and increase the positive cell ratio.Morphologic changes were observed after Wright's staining using inverted phase contrast microscope.The proportion of cells in G0/G1 phase increased while S phase cells decreased.Cell cycle progression was blocked in the G1 phase.The expression of Cyclin E,cyclin D1,CDK2,CDK4,CDK6 mRNA decreased,while PCNA,P21 cip1,P27 kip1 change was not obvious,but P57 (kip2) mRNA expression was increased.Cyclin D1 and CDK4 protein expressions were reduced as well.Conclusions ATPR inhibits the growth of K562 cells and induces differentiation.P57 kip2 plays a key role in differentiation.Moreover,high level of P57kip2 is regulated via inhibiting its degradation through reducing proteasome-dependent proteolysis,and ATPR plays a role in cell cycle arrest.