Antoine Martinez, Pierre Val, Igor Tauveron, J.-L. Kemeny, Coralie Drelon, T. Dumontet, Batisse-Lignier M, Mickael Mathieu, Jérôme Bertherat, Isabelle Sahut-Barnola, Christelle Damon-Soubeyrand, Anne-Marie Lefrançois-Martinez, Frédérique Tissier, G. Marceau, Jean-Christophe Pointud, Génétique, Reproduction et Développement (GReD), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Centre National de la Recherche Scientifique (CNRS), Service de physiologie digestive, urinaire, respiratoire et de l'exercice [CHU Rouen], Hôpital Charles Nicolle [Rouen], CHU Rouen, Normandie Université (NU)-Normandie Université (NU)-CHU Rouen, Normandie Université (NU)-Normandie Université (NU)-Université de Rouen Normandie (UNIROUEN), Normandie Université (NU), Institut Cochin (UMR_S567 / UMR 8104), Université Paris Descartes - Paris 5 (UPD5)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS), CHU Clermont-Ferrand, Centre National de la Recherche Scientifique (CNRS)-Université Clermont Auvergne [2017-2020] (UCA [2017-2020])-Institut National de la Santé et de la Recherche Médicale (INSERM), Normandie Université (NU)-Hôpital Charles Nicolle [Rouen], Hôpital Charles Nicolle [Rouen]-CHU Rouen, Génétique, Reproduction et Développement - Clermont Auvergne (GReD), Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Clermont Auvergne (UCA)-Centre National de la Recherche Scientifique (CNRS), Service de physiologie digestive, urinaire, respiratoire et de l'exercice [Rouen], and Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université Paris Descartes - Paris 5 (UPD5)
Adrenocortical carcinoma (ACC) is a rare cancer with poor prognosis. Pan-genomic analyses identified p53/Rb and WNT/β-catenin signaling pathways as main contributors to the disease. However, isolated β-catenin constitutive activation failed to induce malignant progression in mouse adrenocortical tumors. Therefore, there still was a need for a relevant animal model to study ACC pathogenesis and to test new therapeutic approaches. Here, we have developed a transgenic mice model with adrenocortical specific expression of SV40 large T-antigen (AdTAg mice), to test the oncogenic potential of p53/Rb inhibition in the adrenal gland. All AdTAg mice develop large adrenal carcinomas that eventually metastasize to the liver and lungs, resulting in decreased overall survival. Consistent with ACC in patients, adrenal tumors in AdTAg mice autonomously produce large amounts of glucocorticoids and spontaneously activate WNT/β-catenin signaling pathway during malignant progression. We show that this activation is associated with downregulation of secreted frizzled related proteins (Sfrp) and Znrf3 that act as inhibitors of the WNT signaling. We also show that mTORC1 pathway activation is an early event during neoplasia expansion and further demonstrate that mTORC1 pathway is activated in ACC patients. Preclinical inhibition of mTORC1 activity induces a marked reduction in tumor size, associated with induction of apoptosis and inhibition of proliferation that results in normalization of corticosterone plasma levels in AdTAg mice. Altogether, these data establish AdTAg mice as the first preclinical model for metastatic ACC.