Effects of 48 h combined inhibition of MEK and mTOR on tumour proliferation. Effects of 48 h combined inhibition of MEK and mTOR on tumour proliferation. A. Dual fluorescence image analysis of BrdU and phosphorylated ERK in OCIP23 xenograft models. Representative images (20 × single fields) of tissue sections from OCIP23 xenografts following 48 h treatment stained for phosphorylated ERK (red), BrdU (green) and counterstained for DAPI (blue). The scale bar represents 100 μm. B. BrdU incorporation was measured by flow cytometry in OCIP23 tissue post a 48 h exposure to 6.25 mg/kg b.i.d. RDEA119 and 2 mg/kg rapamycin.