Phosphoinositide 3-Kinase Gamma Inhibition Protects from Anthracycline Cardiotoxicity and Reduces Tumor Growth

Abstract

reserved33Background - Anthracyclines, such as doxorubicin (DOX), are potent anti-cancer agents for the treatment of solid tumors and hematological malignancies. However, their clinical use is hampered by cardiotoxicity. This study sought to investigate the role of PI3Kγ in DOX-induced cardiotoxicity and the potential cardio-protective and anti-cancer effects of PI3Kγ inhibition. Methods - Mice expressing a kinase-inactive PI3Kγ or receiving PI3Kγ selective inhibitors were subjected to chronic DOX treatment. Cardiac function was analyzed by echocardiography and DOX-mediated signaling was assessed in whole hearts or in isolated cardiomyocytes. The dual cardio-protective and anti-tumor action of PI3Kγinhibition was assessed in mouse mammary tumor models. Results - PI3Kγ KD mice showed preserved cardiac function after chronic low-dose DOX treatment, and were protected against DOX-induced cardiotoxicity. The beneficial effects of PI3Kγ inhibition were causally linked to enhanced autophagic disposal of DOX-damaged mitochondria. Consistently, either pharmacological or genetic blockade of autophagyin vivoabrogated the resistance of PI3Kγ KD mice to DOX cardiotoxicity. Mechanistically, PI3Kγ was triggered in DOX-treated hearts, downstream of TLR9, by the mitochondrial DNA released by injured organelles, and contained in autolysosomes. This autolysosomal PI3Kγ/Akt/mTOR/Ulk1 signaling provided maladaptive feedback inhibition of autophagy. Finally, PI3Kγ blockade in models of mammary gland tumors prevented DOX-induced cardiac dysfunction, and concomitantly synergized with the anti-tumor action of DOX, by unleashing anticancer immunity. Conclusions - Blockade of PI3Kγ may provide a dual therapeutic advantage in cancer therapy, by simultaneously preventing anthracyclines cardiotoxicity and reducing tumor growth.mixedLi, Mingchuan; Sala, Valentina; De Santis, Maria Chiara; Cimino, James; Cappello, Paola; Pianca, Nicola; Di Bona, Anna; Margaria, Jean Piero; Martini, Miriam; Lazzarini, Edoardo; Pirozzi, Flora; Rossi, Luca; Franco, Irene; Bornbaum, Julia; Heger, Jacqueline; Rohrbach, Susanne; Perino, Alessia; Tocchetti, Carlo G; Lima, Braulio H F; Teixeira, Mauro M; Porporato, Paolo E; Schulz, Rainer; Angelini, Annalisa; Sandri, Marco; Ameri, Pietro; Sciarretta, Sebastiano; Lima-Júnior, Roberto César P; Mongillo, Marco; Zaglia, Tania; Morello, Fulvio; Novelli, Francesco; Hirsch, Emilio; Ghigo, AlessandraLi, Mingchuan; Sala, Valentina; De Santis, Maria Chiara; Cimino, James; Cappello, Paola; Pianca, Nicola; Di Bona, Anna; Margaria, Jean Piero; Martini, Miriam; Lazzarini, Edoardo; Pirozzi, Flora; Rossi, Luca; Franco, Irene; Bornbaum, Julia; Heger, Jacqueline; Rohrbach, Susanne; Perino, Alessia; Tocchetti, Carlo G; Lima, Braulio H F; Teixeira, Mauro M; Porporato, Paolo E; Schulz, Rainer; Angelini, Annalisa; Sandri, Marco; Ameri, Pietro; Sciarretta, Sebastiano; Lima-Júnior, Roberto César P; Mongillo, Marco; Zaglia, Tania; Morello, Fulvio; Novelli, Francesco; Hirsch, Emilio; Ghigo, Alessandr