OBJECTIVETo study the effects of osteopontin (OPN) on the phenotypes of human hepatocellular carcinoma cell line SMMC-7721.

METHODSHuman hepatocellular carcinoma SMMC-7721 cells were transfected with plasmid pcDNA 3.1(-)/OPN and cells transfected with a mock plasmid served as controls. OPN expression was verified by RT-PCR and Western blot, and concentrations of OPN, MMP-2, MMP-9 and uPA were measured by ELISA. A series of functional assays in vitro were used to monitor the changes of SMMC-7721 malignant phenotypes.

RESULTSOPN expression of SMMC-7721 cells was elevated after transfection. Concentrations of OPN, MMP-2 and uPA in the medium of SMMC-7721 cells after transfection were higher than those of the controls [(3.02+/-0.12) ng/ml vs (1.43+/-0.07) ng/ml, (43.04+/-3.06) ng/ml vs (22.15+/-4.34) ng/ml, and (4.78+/-0.70) ng/ml vs (1.61+/-0.34) ng/ml respectively, P less than 0.01], but MMP-9 concentration did not increase [(7.82+/-2.25) ng/ml vs (7.70+/-1.92) ng/ml]. Functional assays in vitro indicated that SMMC-7721 cells after transfection showed higher adhesive, migrant and invasive capabilities than those of the controls (cell adhesion rates were 75.33%+/-10.59% vs 57.34%+/-2.52%; number of outer surface cells in migrant assay was 14.33+/-2.51 vs 6.34+/-1.53; cell number in the invasive assay was 8.23+/-1.53 vs 4.12+/-1.29 respectively, P less than 0.05).

CONCLUSIONOPN might enhance the expression of MMP-2 and uPA to promote malignant phenotypes of SMMC-7721 cells.