Abstract A02: Neuroblastoma patient-derived orthotopic xenografts: Clinically relevant models for drug testing

Abstract

Abstract Widespread metastasis is a major problem for the treatment of high-risk neuroblastoma. Relevant neuroblastoma animal models are hence needed to study and target high-risk metastatic neuroblastoma. We developed neuroblastoma patient-derived orthotopic xenografts (PDXs) using viably cryopreserved or fresh patient neuroblastoma fragments which were implanted orthotopically into immunodeficient NSG mice. Immunohistochemistry showed that PDXs retain neuroblastoma markers and a highly infiltrative growth pattern. Importantly, we found distant metastasis to lungs, liver and bone marrow. Single nucleotide polymorphism array analysis confirmed that PDXs maintain patient-specific chromosomal aberrations 1p del, MYCN amp and 17q gain. In vitro cultures established from the PDXs express neuroblastoma markers and retain their tumorigenic and metastatic ability in vivo after orthotopic injection. PDXs were highly vascularized with mouse endothelial cells and one PDX model formed tumor vasculature through co-engrafted human tumor endothelial cells. Tumors also contained pericytes, cancer-associated fibroblasts, macrophages and extracellular components resembling the patient disease. PDXs established in athymic nude mice additionally developed intratumoral lymphatic vessels and contained mouse-derived CD45+ lymphoid cells. Thus, PDXs maintain important tumor microenvironment hallmarks for high stage neuroblastoma. Furthermore, we demonstrate the feasibility of using short-term in vitro cultured PDX-derived cells as a drug-testing model, and show that the HIF2A oncogene is transcriptionally regulated at hypoxia via the PI3K/mTORC2 pathway in these cells. The results establish the PI3K and mTORC2 pathways as potential therapeutic targets of aggressive neuroblastoma. In conclusion, neuroblastoma orthotopic PDXs resemble many clinical aspects of the patient disease, e.g., distant metastases, and PDXs are valuable models for preclinical drug testing. Citation Format: Noémie Braekeveldt, Caroline Wigerup, David Gisselsson, Sofie Mohlin, My Merselius, Siv Beckman, Irene Tadeo, Anna P. Berbegall, Ingrid Öra, Samuel Navarro, Rosa Noguera, Sven Påhlman, Daniel Bexell. Neuroblastoma patient-derived orthotopic xenografts: Clinically relevant models for drug testing. [abstract]. In: Proceedings of the AACR Special Conference on Advances in Pediatric Cancer Research: From Mechanisms and Models to Treatment and Survivorship; 2015 Nov 9-12; Fort Lauderdale, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(5 Suppl):Abstract nr A02.