Figure 5. Increased HER2 level induced by resveratrol results in a preferential activation of mTORC1/p70S6K pathway.

Representative western blot analysis of HER2 and HER3 downstream signaling pathways in spontaneous mammary tumors from Δ16HER2 mice, treated or not with resveratrol (left panels), and densitometry quantification from three independent experiments (right panels). (a) PI3K/AKT and (b) mTOR signaling pathways were analyzed. β-actin was used as loading control. The significance was determined by t-test (*p < 0.05; **p ≤ 0.01; ***p ≤ 0.001). (c) Resveratrol promotes the direct coupling of Δ16HER2 to HER3 kinase in HER2+/ERα+ breast cancer. Δ16HER2 kinase co-immunoprecipitates with pHER3. Proteins were immunoprecipitated with anti-HER2 antibody and then probed by western blot for pHER3. Input represents 10% of the co-immunoprecipitation protein amount (30 μg).