Abnormal expression of WIF1 in hepatocellular carcinoma cells and its regulating effect on invasion and metastasis factors of TIMP-3 and caveolin-1 of hepatocellular carcinoma

ABSTRACT

Objective: To discuss the abnormal expression of Wnt inhibitory factor (WIF1) in hepatocellular carcinoma cells and its regulating effect on the hepatocellular carcinoma invasion and metastasis factors of tissue inhibitor of matrix metalloproteinases-3 (TIMP-3) and caveolin-1. Methods: RT-PCR and Western blot were employed to detect the expression of WIF1 in six hepatocellular carcinoma cell lines of HepG2, Hep3B, Huh7, PLC/PRF/5, SMMC-7721 and MHCC97 and the immortalized human liver cell line THLE-3. Besides, Lipofectamine 2000 was employed to transfect the eukaryotic expression vector pcDNA3.1-WIF1 and blank plasmid pcDNA3.1 into hepatocellular carcinoma cell lines. Transwell assay was used to detect the effect of WIF1 on the invasion ability of hepatocellular carcinoma cells; Western blot was used to detect the effect of WIF1 on the expression of TIMP-3 and caveolin-1 in hepatocellular carcinoma cells, it also discussed the effect on the expression of β-catenin. Results: The expression of WIF1 in hepatocellular carcinoma cell lines was lower than that in the normal liver cell lines (P < 0.01); while there was basically no expression of WIF1 in the human highly metastatic cell line MHCC-97 and moderate expression in HepG2 and SMMC-7721. Therefore, HepG2 and SMMC-7721 were chosen as the further experimental cell lines. After transfecting the eukaryotic expression vector pcDNA3.1-WIF1 and blank plasmid pcDNA3.1 into hepatocellular carcinoma cell lines, compared with the blank plasmid group, the cell viability and invasion ability in the WIF1 group were all reduced (P < 0.01), the expression of TIMP-3, caveolin-1 and mRNA were all down-regulated (P < 0.01), and the expression of β-catenin was decreased (P < 0.01). Conclusions: Because of down-regulation or missing of expression of WIF1 in hepatocellular carcinoma cell lines, the up-regulation of WIF1 expression can significantly inhibit the invasion and metastasis of HepG2 and SMMC-7721 of hepatocellular carcinoma cell lines, which are related to the up-regulated expression of TIMP-3 and down-regulated expression of caveolin-1 and may be realized through the Wnt/β-catenin signaling pathway.