RESUMO
Objective To investigate the regulation on cell cycle related factor such as Cyclins and P21waf/cip1 by inhibiting histone deacetylase(HDAC)with valproic acid sodium(VPA).Methods HepG2 hep-tocellular carcinoma cells.BGC-823 gastric carcinoma cells and MCF-7 breast cancer cells were cultured with O.75-4.00 mmoL/L VPA for 48 h in vivo.and the cell cycle was analyzed by flow cytometry with PI assay.The protein and mRNA expression of Cyclin A,Cyclin D1,Cyclin E and P21waf/cip1 were analyzed by indirect immu-nofluorescence technique and RT-PCR.respectively.Results Compared with control groups,VPA at concen-trations 0.75-4.00 mmol/L exerted a significant inhibiting effect on G1 phase of HepG2,BGC-823 and MCF-7 cells(P<0.001).and the effect was dose dependent.Cyclin A was down-regulated both at mRNA and protein level in HepG2 and BGC-823 cells(P<0.001),but no difference in MCF-7 cells(P>0.05).Cyclin D1 was down-regulated both at mRNA and protein level(P<0.001)and P2lwaf/cip1 was up-regulated both at the mRNA and protein level in the three cell lines(P<0.001);Conversely,protein and mRNA expression of Cyclin E were unchanged upon treatment with VPA(P>0.05).Condusion Acetylization of histone intervened with VPA can regulate Cyclin D1 and P21waf/cip1 expressions obviously.To the expression of Cyclin A,it shows some difference according to the histogenesis and phenotypes of different carcinoma types.But there is not any obvious function on Cyclin E.Down-regulating Cychn D1 and up-regulating P21waf/cip1 may be the common target path-way in the inhibition of cell cycle G1 phase exerted by VPA.