Genetic targeting of androgen receptor (AR) is additive in combination with PI3K inhibition. (A) Immunoblot shows AR protein levels at 72 h following transduction with two shRNAs targeting AR (shAR-1 and shAR-2) compared to transduction with nontargeting shRNA (shNT) in the indicated AR + triple-negative breast cancer (TNBC) cell lines. Actin levels are shown for the loading control. (B) Line graphs display relative viability of AR + cell lines transduced with nontargeting (shNT) or shRNAs targeting AR (shAR-1 and shAR-2) after 72 h treatment with increasing concentrations of the pan-PI3K inhibitor GDC-0941 (top) or the dual PI3K/mTOR inhibitor GDC-0980. Error bars represent SD for three independent infections.