Effects of HET0016, rofecoxib, and rofecoxib + HET0016 on MC38 cell proliferation. MC38 cells growing in six-well plates were treated with HET0016 (100 nM to 10 μM; A), rofecoxib (100 nM to 10 μM; B), or HET0016 (1 μM) + rofecoxib (1 μM) (C) for 48 h. Cells were harvested by trypsinization and counted using a hemacytometer. Results are expressed as cell number/well and are means ± SE; n = 5. *P < 0.05, **P < 0.01 vs. vehicle. #P < 0.05, ##P < 0.01 vs. other groups.