To study the effects of phenylacetate(PA) on cell proliferation and homeobox(HOX) genes expression in the colorectal carcinoma HCT-8 cell line, HCT-8 cells were grown in the presence or absence of PA. The cellular proliferation inhibition was evaluated by the MTT assay. Twenty-two HOX genes were divided into three groups(P1, P2, P3) according to their primer sequences, and the samples of cells were analyzed for the HOX genes′ mRNA expression by means of the semi-quantitative reverse transcription-polymerase chain reaction(RT-PCR). The level of the HOX genes′ expression was expressed as the ratio expression rate of HOX gene to the β-actin. HCT-8 cells were treated with 1.0—5.0 mmol/L PA for 24—72 h. With the increase of the PA concentration or the prolongation of the treating time, the cell proliferation is inhibited in a dose- and time-dependent manner. The P1 group mRNA* expression(0.5781±0.0836) is significantly lower than that of the untreated group(0.7701±0.0883) in HCT-8 cells{(p<0.001).} Both the mRNA expressions of groups P2(0.3941±0.0819) and P3(0.5601±0.0736) in the PA treated group are significantly higher than those of the untreated groups P2(0.1221±0.0782) and P3(0.1806±0.0811) in HCT-8 cells(p<0.001). PA could effectively inhibit cell proliferation by regulating the HOX genes expression and the mechanisms of the PA action are correlated with the transcription process in HCT-8 cells.
