Abstract Background: An evolving concept that contributes to the understanding of resistance to androgen deprivation therapy and/or androgen receptor (AR) antagonist in prostate cancer is the ability of the cells to bypass AR blockade and turn on compensatory hormone signaling for survival. Recent preclinical and clinical studies demonstrate that induction of GR expression confers resistance to AR-targeted therapy. Hence therapeutic strategies to overcome GR-mediated resistance are warranted. Experimental Design: Prostate cancer cell-lines and patient derived xenograft (PDX) models were exposed to the pan-AKT inhibitor ipatasertib or other PI3K/AKT- pathway inhibitors with or without AR blockade. AR and GR array determined differentially expressed AR/GR target genes. Protein expression levels were measured. Cell viability and tumor growth was determined in response to treatment. Results: AKT inhibitor as monotherapy significantly decreases cell viability across multiple prostate cancer models. The cytotoxic effect is enhanced by AR inhibition and is most pronounced in models that induce compensatory GR expression. The pan-AKT inhibitor ipatasertib as well as other inhibitors of the PI3K/AKT pathway decreased GR activity through AR-dependent and AR-independent mechanisms. Importantly, AKT inhibition, with and without AR blockade, demonstrated significant anti-tumor activity in several in vivo prostate cancer models with no noticeable toxicity. Conclusion: Inhibition of the PI3K/AKT pathway blocks GR activity and overcomes GR-mediated resistance to AR-targeted therapy. This therapeutic approach has immediate clinical relevance as ipatasertib is currently in advanced clinical development and provides a supportive tool for how to manage patients with acquired resistant to AR-targeted therapy. Citation Format: Remi M. Adelaiye-Ogala, Kathleen Kelly, David VanderWeele. Targeting of the PI3K/AKT pathway overcomes enzalutamide resistance by inhibiting the induction of glucocorticoid receptor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr LB-262.