Tracking cellular and molecular changes in a species-specific manner during experimental tumor progression in vivo

// Emilie Indersie 1, 2, * , Katarzyna B. Hooks 1, 2, * , Caroline Capdevielle 1, 2 , Monique Fabre 3 , Nathalie Dugot-Senant 4 , Angélique Desplat 1, 2 , Sébastien Lepreux 5 , Aksam Merched 1, 2 , Christophe F. Grosset 1, 2 and Martin Hagedorn 1, 2 1 University Bordeaux, INSERM U1035, miRCaDe team, Biothérapie des Maladies Génétiques, Inflammatoires et du Cancer, Bordeaux 33076, France 2 University Bordeaux, INSERM U1035, Bordeaux Research in Translational Oncology (Bariton), Bordeaux 33076, France 3 Necker Hospital, Paris 75015, France 4 Plateforme d’histologie UMS 005, Bordeaux 33000, France 5 Service de Pathologie, CHU de Bordeaux, Bordeaux 33000, France * These authors contributed equally to this work Correspondence to: Martin Hagedorn, email: martin.hagedorn@u-bordeaux.fr Keywords: hepatoblastoma; RNA-sequencing; chick chorioallantoic membrane; bioinformatics; experimental tumor model Abbreviations: CAM: chick chorioallantoic membrane; DE: differentially expressed; HBL: hepatoblastoma; RNA-seq: RNA sequencing Received: February 12, 2018 Accepted: February 21, 2018 Epub: March 01, 2018 Published: March 23, 2018 ABSTRACT Hepatoblastoma (HBL) is a pediatric liver cancer with defined molecular alterations driving its progression. Here, we describe an animal model for HBL on the chick chorioallantoic membrane (CAM), which recapitulates relevant features of HBL in patients. Expression of classic tumor-associated proteins such as β-catenin, EpCAM and CK19 was maintained in acini-like organized tumors on CAM, as was synthesis of AFP, a tumor marker used for monitoring patient response. RNA sequencing revealed an unexpected molecular evolution of HBL cells on the CAM, with significant deregulation of more than 6,000 genes including more than half of all HOX genes. Bioinformatic analysis distinguish between tumor cell-expressed genes and chick genes, thereby shedding new light on the complex interactions taking place during HBL progression. Importantly, human tumor suppressive ribosomal genes were downregulated after implantation, whereas mitochondrial genes encoding for anti-apoptotic peptides were strongly induced in vivo . Meprin-1α expression was increased during evolution of CAM tumors and confirmed by immunohistochemistry. Cisplatin, a commonly used chemotherapeutic agent for HBL, showed significant anti-tumoral effects. Our results broaden the understanding of the molecular adaptation process of human cancer cells to the microenvironment and might help to elaborate novel therapeutic concepts for the treatment of this pediatric liver tumor.