Effects of hydralazine and valproate on the expression of E-cadherin gene and the invasiveness of QBC939 cells

Abstract

To clarify the effect of DNA methylation and histone deacetylase inhibitors on the expression of the E-cadherin gene and the invasiveness of the QBC939 cells, the QBC939 cells were separately treated with hydralazine, valproate, or combination of the two drugs. The expression of E-cadherin mRNA and protein was examined by reverse transcription-polymerase chain reaction (RT-PCR), and Western blot.The methylation status of the promoter region of the gene was detected by methylation-specific PCR (MSP). The invasiveness of QBC939 cells was tested by transwell assay. It was found that the promoter region of the E-cadherin gene of QBC939 cells was hypermethylated. Valproate alone could not contribute to demethylation of the gene, whereas hydralazine could make them to be partly demethylated. However, the methylation status of the gene could be thoroughly reversed by using valproate and hydralazine in combination. What’s more, it was confirmed that the E-cadherin gene of QBC939 cells could not be transcriptionally reactivated by valproate alone, whereas hydralazine alone could induce moderate reexpression of the gene. However, the addition of valproate to hydralazine could result in robust reexpression of the E-cadherin gene (P = 0.000). Likewise, the invasiveness of the QBC939 cells was sharply decreased by treatment with two drugs in combination and slightly decreased with one drug alone. It could be concluded that the two drugs have synergistic effect on the demethylation and reexpression of the E-cadherin gene of QBC939 cells, and also on the reduction of the invasiveness of the QBC939 cells.