Effect of silencing RRM2 by specific small interference RNA on biological behaviors of human hepatoma cancer cell line HepG2

Abstract

Objective To investigate the effect of small interference RNA (siRNA) silencing RRM2 on the biological behaviors of human hepatoma cancer cell line HepG2 and and the molecular mechanisms.Methods RRM2 expression was knocked down in human hepatoma cancer cell line HepG2 by RRM2 siRNA.The expression level of RRM2 was detected in human hepatoma cancer cell line HepG2 and human normal liver cell line HL-7702 at mRNA and protein levels by real-time polymerase chain reaction (PCR) or Western blotting.The cell proliferation was measured by cell counting Kit-8 (CCK-8).The migration was observed by using Transwell cell migration system.The expression levels of B lymphocytes/leukemia-2 (bcl-2),bax and cytochrome C (Cyt-C) proteins were detected by using Western blotting.Ten male BALB/C nude mice were subcutaneously injected with siRNA-RRM2/HepG2,siRNA-NC/HepG2 or NEG/HepG2 cells respectively to study the growth of tumor in each group.Results siRNA-RRM2 could down-regulate the expression of RRM2 in HepG2 remarkably,and siRNA-RRM2 could inhibit both the proliferation [(41.20 ± 2.13) ％ vs (91.35 ± 10.22) ％] and migration ability of HepG2 cells (21.20 ±1.28 vs 132.50 ±7.88) as compared with the negative control group.siRNA-RRM2 could down-regulate the expression of bcl-2 and up-regulate the expression of bax and Cyt-C.Additionally,the volume of xenograft tumors in siRNA-RRM2 group was decreased significantly as compared with control group.The volume of xenograft tumors in siRNA-RRM2 group was (171.13 ± 28.12) mm3 and that in siRNA-NC group was (1487.41 ± 168.20) mm3 at 8th week.Conclusion siRNA-RRM2 can down-regulate the expression of RRM2 in the HepG2 cells and may play an important role in the regulation of biological behaviors of HepG2 cells,and also inhibit the tumor growth of nude mice model. Key words: RNA interference ; RRM2 gene ; Carcinoma,hepatocellular