[Knocking down osteopontin expression by specific siRNA reduces the in vitro invasiveness of human hepatocellular carcinoma cells].

OBJECTIVE: To study the effect of osteopontin (OPN) expression down-regulated by RNA interference (RNAi) on the invasiveness of hepatocelluar carcinoma cell line HCC-LM3. METHODS: HCC-LM3 cells were transfected with the chemically synthesized small interfering RNA (siRNA) formulated by lipofectamine 2000. Wild type HCC-LM3 and HCC-LM3 cells transfected with non-specific siRNA served as controls. Real-time PCR and Western blotting were used to quantify the mRNA and OPN protein levels. The malignant phenotypes of transfected HCC-LM3 cells including cellular growth rate, colony formation and Matrigel invasion activities were analyzed. RESULTS: Sequence-specific siRNAs targeting OPN suppressed OPN RNA expression by 79% and also decreased OPN protein level by 81% in HCC-LM3 cells. The number of formed colonies and migrating numbers in vitro were decreased in HCC-LM3 cells transfected using sequence-specific siRNAs targeting OPN relative to controls (P < 0.05). CONCLUSION: This study demonstrated that specific siRNA is able to reduce OPN at both the mRNA and protein levels and significantly diminishes the invasiveness of hepatocellular carcinoma cells.