OBJECTIVESTo study the effects of tumor suppressor in lung cancer-1 (TSLC1) on human hepatocyte carcinoma cell line HepG2.

METHODSA full length of TSLC1 cDNA was amplified from RNA of normal human liver cells by RT-PCR, and it was cloned into a pCI-neo expression vector and transfected into human hepatocellular carcinoma cell line HepG2. The HepG2 cells transfected with this plasmid (experimental group) and those treated with pCI-neo vector (control group) and without any treatment (blank group) were compared. Cell morphology was studied microscopically and cell growth was analyzed with MTT assay. FACSort flow cytometry analysis was performed to assess the cell cycle distribution and apoptosis.

RESULTSA stable cell line expressing TSLC1 protein was successfully established. Morphologically, cells of the experimental group were tightly aggregated when compared with those of the control and blank groups. The growth of TSLC1-transfected cells was significantly suppressed in vitro compared with those of the control and blank groups. The amount of G0-G1 cells was 63.66%+/-3.83% (P less than 0.01) in the experimental group, while those of the control and blank groups were 47.45%+/-0.91% and 54.47%+/-0.96% respectively. The amount of S phase cells in the experimental group, 22.90%+/-6.04%, was significantly lower (P less than 0.05) than that of the control group (36.58%+/-0.61%) and the blank group (33.61%+/-2.99%), which suggested a G0-G1 cell cycle arresting. The number of cells in early and late phase apoptosis (17.09%+/-0.20% and 16.11%+/-0.40% respectively) were significantly higher than those of the control and blank groups (P less than 0.01).

CONCLUSIONSTSLC1 strongly inhibits the growth of HepG2 cells in vitro and induces apoptosis of the cells, suggesting that TSLC1 may have a tumor suppressor function in HCC.