Figure 3. COX-2 expression inhibits PI staining in liver cells.

Cells resuspended in PBS were PI-stained, and cell-cycle analysis was determined by flow cytometry. (A) Effect of FBS concentration on the percentage of apoptotic CHL-V and CHL-C cells after 72 h of culture. (B) Time-dependent apoptosis and PGE₂ concentrations in CHL-V and CHL-C cells cultured without FBS. The inset shows the level of PGE₂ in each cell type over the same time period. (C) Representative DNA histograms and G₁ profiles showing the PI staining from CHL-V and CHL-C cells cultured at 0 and 10% (v/v) FBS for 72 h. (D) Effect of exogenous PGE₂ on the percentage of apoptotic cells. (E) Effect of DFU on the percentage of apoptotic CHL-C cells (no FBS, 72 h of culture). (F) Western blot analysis of COX-2 expression in HepG2-V and HepG2-C. (G) Apoptosis of HepG2-V and HepG2-C cells without FBS after 72 h of culture. Results are means±S.D. for four independent experiments. *P<0.05 compared with paired CHL-V cells. ◆P<0.05 compared with cells at zero time (B) or untreated cells (D and E).