Effect of up-regulating lncRNA-HEIH by HBx on proliferation of hepatocellular carcinoma cells

Objective To investigate the effect of up-regulating long noncoding RNA high expression in hepatocellular carcinoma (lncRNA-HEIH) by HBx on the proliferation of hepatocellular carcinoma (HCC) cells. Methods The samples were collected from 30 patients with hepatitis B virus (HBV)-related HCC who received surgery in the Third Affiliated Hospital of Sun Yat-sen University and Cancer Center of Sun Yat-sen University between September 2015 and March 2016. The informed consents of all patients were obtained and the local ethical committee approval was received. Among 30 patients, 24 were males and 6 were females, aged 20-65 years old with a median age of 52 years old. The expression levels of HBx mRNA and lncRNA-HEIH mRNA in the HCC tissues and paracarcinoma tissues were detected by RT-PCR. HCC cell lines SMMC-7721-HBx and Bel-7404-HBx stably expressing HBx were established as the experimental cells. And the control cells SMMC-7721-Vector and Bel-7404-Vector were also established. The expression of lncRNA-HEIH in the cell lines was detected by RT-PCR and Western blot. According to siRNA-HEIH was transfected or not, the experimental cells were respectively divided into the interference group and the non-interference group. The absorbance values (A490) of two groups were detected by MTT. The experimental data were compared using t test. The relationship between the expression of lncRNA-HEIH and HBx was analyzed using Pearson correlation analysis. Results The expression levels of HBx mRNA and lncRNA-HEIH mRNA in the HCC tissues were respectively 0.91±0.04 and 0.93±0.05, significantly higher than 0.53±0.01 and 0.35±0.02 in the paracarcinoma tissues (t=7.95, 10.42; P<0.05). The expression level of lncRNA-HEIH mRNA was positively correlated with that of HBx mRNA (r=0.840, P<0.05). The expression level of lncRNA-HEIH in the SMMC-7721-HBx and Bel-7404-HBx cells was respectively 1.05±0.22 and 1.20±0.17, significantly higher than 0.45±0.10 and 0.50±0.12 in the control cells (t=5.69, 3.78; P<0.05). The A490 in the SMMC-7721-HBx and Bel-7404-HBx interference groups was respectively 0.26±0.05, 0.38±0.04, 0.43±0.10 and 0.27±0.05, 0.30±0.12, 0.39±0.05 at 48, 72 and 96 h, significantly lower than 0.37±0.07, 0.59±0.12, 0.80±0.10 and 0.38±0.07, 0.62±0.12, 0.78±0.11 in the non-interference group (t=-5.72, -3.47, -3.82 and -3.89, -5.57, -8.34; P<0.05). Conclusions High expression of lncRNA-HEIH is probably correlated with the incidence of HBV-related HCC. HBx gene is involved in promoting the proliferation of HCC cells via up-regulating the expression of lncRNA-HEIH. Key words: Liver neoplasms; HBx; LncRNA-HEIH; Proliferation