Constitutive activation of MEK1 or MEK2 confers intestinal epithelial cells resistance to anoikis. (A) IEC-6 cell populations infected with vector alone or activated MEK1 or MEK2 were cultured in suspension on poly-HEMA-coated plates for the indicated times. Apoptosis was evaluated by TUNEL assay. (B and C) Expression of Bcl-2 anti-apoptotic (B) and pro-apoptotic (C) family proteins was analyzed by immunoblotting in cell extracts from IEC-6 cell populations described in A. Total actin was used as loading control.