EGF treatment but not silencing of REDD1 provides a partial protective effect against TAIII cytotoxicity.
A. Levels of REDD1 and phosphorylation of s6 protein in MDAMB231 cells transduced with control (231-vec) or REDD1 siRNA expressing lentivirus (231-REDD1KD). Cell extracts were analyzed by Western blotting before and 4 hours after treatment with 5 µM of TAIII. B. Effect of addition of exogenous EGF on survival of BT474 and MDAMB231 cells treated with TAIII for 24 hours (4 µM for BT474 and 7.5 µM for MM231). C. Effect of exogenous EGF on Akt activity, mTORC1 activity and mTOR phosphorylation in cells treated with TAIII for 16 hours. Western blotting was done with the phospho-specific antibodies and antibodies detecting total levels of the indicated proteins.