OBJECTIVETo investigate the different expressions of cytoskeletal organizer ezrin and cytoskeleton protein beta- and gamma-actin in hepatocellular carcinoma (HCC) cell lines with different metastatic potentials and to explore the role of ezrin in cell growth and metastasis in HCC cell lines SF7721 and MHCC97-H.

METHODSImmunofluorescence, RT-PCR and Western blot were used to detect the gene and protein expressions of ezrin and actin in hepatocellular carcinoma cell lines with different metastatic potentials. RNA interference (RNAi) was applied to down-regulate the ezrin expression in SF7721 and MHCC97-H. Changes of the cell growth and metastasis potentials after the RNAi treatment were studied. MTT assay was used to detect cell proliferation changes and Transwell assay was applied to observe the changes of cell motility and invasiveness.

RESULTSBoth ezrin and cytoskeleton protein were demonstrated in the cytoplasma of the cells at the same time. The expression of them in cell lines with high metastatic potential, such as SF7721, MHCC-1 and MHCC97-H was obviously higher than in those with low metastatic potentials, such as SMMC-7721, Hep3B and HepG2 (chi2= 13.277, P = 0.010; chi2= 21.815). The mRNA and ezrin and cytoskeleton protein gamma-actin were over-expressed in HCC cell lines with high metastatic potentials. The expressions of beta-actin of cell lines with different metastatic potentials showed no differences. Ezrin protein was successfully down-regulated and the proliferation and the invasiveness of the cells decreased with low ezrin protein level in SF7721 and MHCC97-H.

CONCLUSIONOver-expression of ezrin and cytoskeleton protein gamma-actin are associated with the process of metastasis of hepatocellular carcinoma cells. The growth and invasiveness of SF7721 and MHCC97-H cells can be inhibited by down-regulating ezrin expression.