Fig. 4

The effect of vorinostat on cyclin D1 expression and histone modification. a Cyclin D1 expression was analyzed in A549, H460, and H226 cells treated with vorinostat and/or B[a]P. Cellular lysate protein (30 μg/lane) was loaded onto a 10 % SDS/PAGE gel, electrophoresed, and subsequently immunoblotted with a cyclin D1 antibody. b The effect of vorinostat and cyclin D1 siRNA on cyclin D1 down-regulation was compared in A549 cells. The cells were transfected with 75 nM of cyclin D1 siRNA for 2 days (lanes 2 & 5) or with 5 μM vorinostat for 1 day (lanes 3 & 6), The cyclin D1 expression in the presence of B[a]P was analyzed after pretreatment of cells with B[a]P for 9 days (lane 4 through lane 6). c & d Dimethylation of H3K9 histone tail at the promoter of cyclin D1 was analyzed using chromatin immunoprecipitation (ChIP) after incubating A549 cells as described in the Materials and Methods. The intensities of bands were measured using a densitometer and are presented as relative band intensities compared to control. Error bars indicate one standard deviation