Sodium selenite inhibited cell proliferation in human colon cancer lines HCT116 and SW620. A and C, cell proliferation inhibition by sodium selenite occurred in a dosage dependent manner (48h); B and D, inhibition of cell proliferation by sodium selenite was time-dependent (5 μmol/L). * p<0.01, compared to the control group (0 μmol/L, or 0 h, respectively). These experiments were triplicated independently.