RNA interference silencing EZH2 gene strengths the sensitivity of human hepatic multidrug-resistant cancer cells to 5-Fu chemotherapy

Abstract

Objective To study the impact of EZH2 silence on the sensitivity of human hepatic multidrug-resistant cancer cells Bel/Fu to 5-Fu. Methods Bel/Fu cells were cultured in vitro; EZH2 siRNA was used to interfere EZH2 expression; RT-PCR and Western blot was used to detect the efficiency of interference.MTT assay was used to detect the cellular growth inhibitory rate; Annexin V-FITC/PI double staining was used to detect the apoptosis rate of cells ; Flow cytometry was to analyze cell cycle ; Western blot analysis was used to detect the expression of multidrug resistance-associated protein MDR1 after silencing EZH2.The experiment set up four groups:control group,5-Fu treatment group,EZH2 siRNA treatment group,5-Fu combined with EZH2 siRNA treatment group. Results The expression of EZH2 was greatly decreased after 24 h in the combined group,the apoptotic inhibitory rate by MTT was 43.17％ ± 3.81％,higher than other three groups; the apoptotic rate in the combined group by Flow cytometry was 30.4％ ± 1.77％,markedly higher than other three groups.The cell cycle of the combined group detected by Flow cytometry was 69.16％ ±2.31％ of cells in the combined group at G1 phase,the percentage was higher than other three group,30.76％ ± 1.29％ at S,G2 and M phases,lower than other three groups,indicating the cell cycle was blocked at G1 phase.MDR1 protein level in the combined group was lower than other groups.Conclusions Silencing EZH2 strengths the sensitivity of Bel/Fu cells to 5-Fu,probably by a mechanism decreasing the expression of MDR1. Key words: Liver neoplasms; Gene silencing; RNA interference; Multidrug resistance-associated proteins