Effect of specific hTERT-siRNA on growth of human tongue cancer cells in vivo and in vitro

AIM:To investigate the effect and mechanisms of siRNA-hTERT-induced inhibition of Tca8113 tongue cancer cells in vitro and in vivo. METHODS:A small interference RNA (siRNA) targeting to hTERT mRNA (siRNA-hTERT1) was constructed. The siRNA was transfected into Tca8113 tongue cancer cells in vivo and in vitro with cationic liposome. A non-specific siRNA (siRNA-hTERT2) and non-treatment were used as negative control group and blank group. The cell growth in vitro was detected by MTT method. The cell apoptosis in vitro was analyzed by flow cytometry. The effect of siRNA-hTERT1 on xenografts in nude mice was observed by determining the tumor size. The cell apoptosis in xenografts was analyzed by Hoechst staining. The expressions of hTERT mRNA in vitro and in vivo were detected by RT-PCR. RESULTS:The inhibition rates of cell growth in vitro 72 h after siRNA-hTERT1 treatment was 47.2%,significantly higher than that in siRNA-hTERT2 treatment group (2.6%,P0.01). The cell apoptosis rate was 27.30%±0.18% in vitro,significantly increased at 48 h after transfection of siRNA-hTERT1,compared to negative control group and blank group (P0.01). The size of xenografts in siRNA-hTERT1 treatment group was (298.8±138.7)mm3,significantly smaller than that in siRNA-hTERT2 treatment group and blank group (495.1±151.6)mm3 and (506.8±207.4)mm3,the inhibition rate was 40.0% (P0.01). The numbers of apoptotic cells in xenografts significantly increased after transfection of siRNA-hTERT1,compared to negative control group and blank group (P0.01). Compared to negative control group and blank group,the expression of hTERT mRNA in Tca8113 tongue cancer cells in vitro and in vivo was inhibited by siRNA-hTERT1. CONCLUSION:siRNA-hTERT1 powerfully inhibits the growth of Tca8113 tongue cancer cells in vitro and in vivo. The specific inhibition of hTERT mRNA expression and cell apoptosis may be its main mechanisms.