Figure 1. Loss of APC leads to increased activation of STAT3.

(A) Western blot analysis demonstrates that MMTV-PyMT;Apc^Min/+ cells have increased pSTAT3 but similar levels of total STAT3. (B) Quantification of pSTAT3/STAT3 in MMTV-PyMT;Apc^Min/+ vs MMTV-PyMT;Apc^+/+ cells shows a significant increase in activated STAT3. (C) Western blot results were confirmed using a dual luciferase reporter assay. Cells were transfected with STAT3 and pRL-TK reporter plasmids for 24 hours and luciferase activity was measured. (D) IL-6 production was measured in media using ELISA, and no difference was observed between MMTV-PyMT;Apc^+/+ and MMTV-PyMT;Apc^Min/+ cells. (E) Representative western blots for total EGFR show an increase in MMTV-PyMT;Apc^Min/+ compared to MMTV-PyMT;Apc^+/+ cells. (F) Quantification of EGFR normalized to actin shows that MMTV-PyMT;Apc^Min/+ cells express higher levels of EGFR compared to MMTV-PyMT;Apc^+/+ cells. (G) Representative western blots for the anti-apoptotic proteins, Bcl-2 and Mcl-1, and quantification (H) shows that Bcl-2 is increased in MMTV-PyMT;Apc^Min/+ cells compared to MMTV-PyMT;Apc^+/+ cells, while Mcl-1 (I) is unchanged. Actin was used as a loading control for all western blot experiments. Each experiment was repeated 3 times and data are shown as means +/- SD; *P < 0.05 comparing MMTV-PyMT;Apc^Min/+ to MMTV-PyMT;Apc^+/+ cells.