GDC-0449 improves the anti-proliferation activity in NIH-3T3 cells but not in BxPC-3, Panc-1, MIAPaca-2 and SW1990 cells when cultured alone. The cytotoxicities of GDC-0449, Dox or Dox with GDC-0449 (5 μM or 10 μM) were measured by performing a 48-h MTT assay in BxPC-3 (A), Panc-1 (B), MIAPaca-2 (C), SW1990 (D) and NIH-3T3 (E) cells. Apoptosis rate was detected by flow cytometry (Annexin V staining) analysis after treatment with Dox (200 nM) with or without GDC-0449 for 24 h (F). Data are presented as the mean ± SD. *P < 0.05, **P < 0.01.