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.
OBJECTIVE To observe the effect of phenylacetate on the expression of RNA editing deaminase ADAR2 mRNA in glioma cells. METHODS Primary glial cells from human brain tissue and glioma U-251MG cells were cultured. The expression of ADAR2 mRNA was detected by a semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The levels of ADAR2 mRNA expression before and after treatment with phenylacetate were tested by RT -PCR and image analysis. The level of ADAR2 gene expression was presented as the ratio expression rate (RER) of ADAR2 gene/β-actin based on computer image analysis. RESULTS The ADAR2 mRNA displayed mild expression in brain glial cells, and a high expression level in high-grade malignant U-251MG glioma cells. Computer image analysis showed that the RERs of the ADAR2 gene in the U-251MG cells before and after treatment with 4.0, and 5.0 mM phenylacetate for 8 h were 100.0, 73.5, 60.3, respectively. The expression of ADAR2 mRNA was decreased by phenylacetate in glioma U-251MG cells. CONCLUSION Phenylacetate can decrease the expression of ADAR2 mRNA in glioma cells, suggesting that phenylacetate, as a drug, may act on the course of RNA editing in gliomas.
Yu TianYuzuo PanYufei GaoGuilin LiJun GaoXingli ZhaoGuiying LiRenzhi Wang
To study the expression of RNA editing deaminases ADAR2 and ADAR3 in different malignant glioma cell lines and the effect of phenylacetate on the expression of these genes, the primarily glial cells of human brain tissue were isolated and cultured. The human glioma SHG-44, U-251, BT-325 cell lines were maintained in culture. The expressions of ADAP,.2 and ADAR3 mRNA were detected by the semiquantitative reverse transcription-polymerase chain reaction（RT-PCR）. The changes in ADAR2 mRNA expression before and after phenylacetate treatment were detected by RT-PCR and image analysis. The level of ADAR gene expression is expressed as the ratio expression rate（RER） of ADAR gene to β-actin according to computer image analysis. ADAR2 displays moderate expression in glial cells, low expression in low-grade malignant glioma SHG-44 cells, and high level expression in high-grade malignant glioma U-251and BT-325 cells. The expression of ADAR2 can be decreased by phenylacetate treatment in glioma U-251 cells. ADAR3 is not expressed in normal brain glial cells, or glioma SHG-44, U-251 and BT-325 cells before and after phenylacetate treatment. The enhanced expression of ADAR2 may be involved in the tumor progression of malignant glioma. Phenylacetate can decrease the expression of ADAR2 in glioma cells, suggesting that it may act on the RNA editing process in glioma.
