Hepatoma cell line HepG2.2.15 demonstrates distinct biological features compared with parental HepG2

Figure 1 Ultrastructure of HepG2. 2.15 and HepG2 cells. A: Filopodia disappearance in HepG2.2.15 cells (EM × 2500); B: Viral inclusion bodies in the cytoplasm of HepG2.2.15 cells. Arrows indicate the viral inclusion bodies (EM × 15 000); C: Arrows indicate degenerated mitochondria (EM × 25 000); D: Plentiful filopodia around HepG2 cells. Arrows indicate filopodia (EM × 2500); E: Microfilament appearance in filopodia in HepG2 cells in high power field. Arrows indicate microfilament (EM × 25 000); F: Abundant organelles in the cytoplasm of HepG2 cells (EM × 25 000).

Figure 2 Cell proliferation and apoptosis flow cytometry. A: The levels of hepatitis B surface antigen (HBsAg) and hepatitis B envelope antigen (HBeAg) in HepG2.2.15 cell supernatant. The supernatant was collected every 24 h and tested by enzyme-linked immunosorbent assay; B: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay of cell proliferation. The absorbencies of test wells were read every 24 h and the data represent the mean ± SD (^bP < 0.001); C: Flow cytometry of cell cycle; D: Apoptosis percentages in B1, B2 and B4 areas. All experiments were repeated three times with similar results.

Figure 3 Invasion assays of HepG2 and HepG2. 2.15 cells. The trans-well membranes were collected at different time points and the cells that went through the pores were stained with hematoxylin and eosin. The cell numbers were counted. A: HepG2 cells collected and stained at 2 h, 4 h, 6 h and 12 h after incubation; B: HepG2.2.15 cells collected and stained at 24 h, 36 h, 48 h and 60 h after incubation; C: Western blotting analysis of F-actin and Ezrin.

Figure 4 Tumor formation of HepG2 and HepG2. 2.15 cells in vivo. A: The volume of subcutaneous tumors were measured and recorded every 2 d. The difference of tumor growth rate between HepG2 and HepG2.2.15 groups was significant (P < 0.01, Mann-Whithey U test); B: Tumor development in four groups in vivo; C: Expansive growth of tumor. The boundary of tumor and normal tissue is clear [hematoxylin and eosin (HE) stain, × 120]. T: Tumor; H: Liver tissue; D: Fatty changes in liver tissue of HepG2.2.15 groups (HE stain, × 120); E: Lung metastasis in HepG2 injected group (HE stain, × 460) and low power field.