Figure 4.

Combined AZD1480/AZD6244 treatment decreases tumor growth, tumor burden and proliferation while retaining the pancreatic integrity. Tumor growth rate of PDAC cells PANC1 (A) and MiaPaCa2 (B) flank xenografts in Fox 1-nu/nu mice treated with vehicle, AZD1480 (30 mg/kg/day), AZD6244 (25 mg/kg/day) or AZD1480/AZD6244. Error bars indicate SD of mean; n = 4 (PANC1) or n = 3 (MiaPaCa2) per group. (C and D) Immunohistochemistry of pancreatic tumor xenograft tissues show decreased Ki-67 (C) and increased cleaved caspase 3 (Cl Casp 3) expression with MEKi/STAT3i treatment and analyzed using Image J (lower panels). (E, F and G) PKT mice received AZD1480, AZD6244 or AZD1480/AZD6244 by oral gavage 5 days/week, starting at 4 weeks of age for 2 weeks. E, total pancreatic tumor weight was measured at the end of treatment at 6 weeks of age. Treatment of MEKi and MEKi/STAT3i showed a significantly reduced weight compared to vehicle treated mice. (F and G) The relative tumor area (F) was measured and the histological sections of pancreatic tissue were stained for Cytokeratin 19 (CK-19), alcian blue, collagen 1 and Ki67 (G, left panels), and analyzed for the PDAC tumor integrity. The expression of the CK-19, alcian blue, Collagen 1 and Ki67 stains were calculated and analyzed using Image J (right panels). WT: wild type; *, P < 0.05; **, P < 0.01; ***, P < 0.001; ****, P < 0.0001; ^ns, P > 0.05.