AKT3 and melanoma: In order to investigate the possible contribution of AKT isoforms to metastatic potential in human cell lines, we generated luciferized doxycycline-inducible shRNA hairpins to AKT1, AKT2, and AKT3 [34], as well as a nontargeting hairpin (shNT) that efficiently reduced protein expression in the majority of melanoma cell lines from our panel, (Figure 1A,B and Figure S1C–E) without affecting viability (Figure 1C).