Modeling germline mutations in pineoblastoma uncovers lysosome disruption-based therapy

• Published in: Nature communications 2020-04, Vol.11 (1), p.1825-19, Article 1825
• Main Authors: Chung, Philip E. D., Gendoo, Deena M. A., Ghanbari-Azarnier, Ronak, Liu, Jeff C., Jiang, Zhe, Tsui, Jennifer, Wang, Dong-Yu, Xiao, Xiao, Li, Bryan, Dubuc, Adrian, Shih, David, Remke, Marc, Ho, Ben, Garzia, Livia, Ben-David, Yaacov, Kang, Seok-Gu, Croul, Sidney, Haibe-Kains, Benjamin, Huang, Annie, Taylor, Michael D., Zacksenhaus, Eldad
• Format: Article
• Language: English
• Subjects: 13/2; 13/51; 14; 14/19; 38; 38/39; 64; 64/60; 692/4028/67/1922; 692/4028/67/2332; 692/4028/67/70; Animals; Antidepressants; Autophagosomes - drug effects; Autophagosomes - metabolism; Autophagosomes - ultrastructure; Autophagy - drug effects; Brain cancer; Cancer; Cathepsin B; Cell death; Children; Cluster Analysis; Deactivation; Disease Models, Animal; Gemcitabine; Gene Deletion; Germ-Line Mutation - genetics; Humanities and Social Sciences; Humans; Inactivation; Integrases - metabolism; Kaplan-Meier Estimate; Lysosomes - drug effects; Lysosomes - metabolism; Malignancy; Mammary gland; Mammary glands; Meninges; Metastases; Metastasis; Mice; multidisciplinary; Mutation; Neoplasia; Neoplasm Metastasis; Nortriptyline - pharmacology; Nortriptyline - therapeutic use; p53 Protein; Pediatrics; Pineal gland; Pinealoma - drug therapy; Pinealoma - genetics; Pinealoma - pathology; Pinealoma - ultrastructure; Pregnancy; Retinoblastoma Protein - metabolism; Science; Science (multidisciplinary); Suppressors; Tricyclic antidepressants; Tumor Suppressor Protein p53 - metabolism
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-020-15585-2

Pineoblastoma is a rare pediatric cancer induced by germline mutations in the tumor suppressors RB1 or DICER1 . Presence of leptomeningeal metastases is indicative of poor prognosis. Here we report that inactivation of Rb plus p53 via a WAP-Cre transgene, commonly used to target the mammary gland during pregnancy, induces metastatic pineoblastoma resembling the human disease with 100% penetrance. A stabilizing mutation rather than deletion of p53 accelerates metastatic dissemination. Deletion of Dicer1 plus p53 via WAP-Cre also predisposes to pineoblastoma, albeit with lower penetrance. In silico analysis predicts tricyclic antidepressants such as nortriptyline as potential therapeutics for both pineoblastoma models. Nortriptyline disrupts the lysosome, leading to accumulation of non-functional autophagosome, cathepsin B release and pineoblastoma cell death. Nortriptyline further synergizes with the antineoplastic drug gemcitabine to effectively suppress pineoblastoma in our preclinical models, offering new modality for this lethal childhood malignancy. Pineoblastoma is a rare pediatric cancer. Here, the authors present inactivation of Rb plus p53 via a WAP-Cre transgene induces metastatic pineoblastoma resembling human disease, and using this model, predict tricyclic antidepressants as a potential therapy for pineoblastoma, supported by their pre-clinical model.