Figure 3.
IGF-I signaling mediates AKT activation induced by mTOR inhibition. A and B, the induction of pAkt (S473) by rapamycin was abrogated by the small-molecule inhibitor of IGF-IR, NVP-AEW541, and by the monoclonal antibody against IGF-IR, A12, in both the DU-145 prostate cancer cell line (A) and the MCF-7 breast cancer cell line (B). Total Akt levels did not change.
C, 1 nmol/L rapamycin treatment up-regulates IRS-1 levels in MCF-7, DU-145, and MDA-MB-468 cell lines by 1 hour, and this induction persists for 24 hours. IRS-2 levels remain unchanged.