Figure 5. Increased cell proliferation in Apc-mutant tumor cells is dependent on active Src and JNK signaling.

(A) Western blotting was performed on total cell lysates from the tumor cell lines with antibodies to detect total and phosphorylated forms of JNK, FAK and Src. Increased phosphorylation of JNK, FAK, and Src is observed in the MMTV-PyMT;Apc^Min/+ tumor cells compared to control cells. Actin was used as a loading control. (B) Tumor cell proliferation was assessed using BrdU incorporation and staining with an anti-BrdU antibody. Quantification shows that, consistent with the in vivo studies, MMTV-PyMT;Apc^Min/+ tumor cells have enhanced proliferation compared to control cells. Treatment of the MMTV-PyMT;Apc^Min/+ cells with an inhibitor of Src, a high dose of the JNK inhibitor (30 µM) or a combination of Src and JNK inhibitors for 12 h significantly inhibited their BrdU incorporation, reducing it to levels similar to control cells (*p<0.05 MMTV-PyMT;Apc^Min/+ cells compared to control, PP2-treated, and PP2/SP600125-treated cells).