In contrast, 5 out of 5 TNBC lines tested express Akt3, and 3 of them are insensitive to GDC-0068 (MDA-MB-468, MDA-MB-231, MCF10A: IC50 >10 μM; BT-549: IC50 5.6 μM; Hs578T IC50 2.2 μM). Consistent with this, we show that MDA-MB-231 and MCF10ADCIS cells are resistant to the pan-Akt inhibitor GSK690693. Importantly, Akt3 depletion in both lines resulted in robust sensitization to the drug, suggesting a critical role of Akt3 in conferring resistance to pan-Akt inhibitor in TNBCs.