RPS6 and acute myeloid leukemia: Using different AML cell lines (U937, MM6 and Kasumi-1), we analyzed the effects of these agents on the phosphorylation of AKT on serine 473 (Ser473), a marker of mTORC2 activity, and the phosphorylation of S6 ribosomal protein (rpS6) and eukaryotic translation initiation factor 4E-binding protein 1 (4E-BP1), markers of mTORC1 activity.