Neuroblastoma patient‐derived orthotopic xenografts retain metastatic patterns and geno‐ and phenotypes of patient tumours

Abstract

Neuroblastoma is a childhood tumour with heterogeneous characteristics and children with metastatic disease often have a poor outcome. Here we describe the establishment of neuroblastoma patient-derived xenografts (PDXs) by orthotopic implantation of viably cryopreserved or fresh tumour explants of patients with high risk neuroblastoma into immunodeficient mice. In vivo tumour growth was monitored by magnetic resonance imaging and fluorodeoxyglucose–positron emission tomography. Neuroblastoma PDXs retained the undifferentiated histology and proliferative capacity of their corresponding patient tumours. The PDXs expressed neuroblastoma markers neural cell adhesion molecule, chromogranin A, synaptophysin and tyrosine hydroxylase. Whole genome genotyping array analyses demonstrated that PDXs retained patient-specific chromosomal aberrations such as MYCN amplification, deletion of 1p and gain of chromosome 17q. Thus, neuroblastoma PDXs recapitulate the hallmarks of high-risk neuroblastoma in patients. PDX-derived cells were cultured in serum-free medium where they formed free-floating neurospheres, expressed neuroblastoma gene markers MYCN, CHGA, TH, SYP and NPY, and retained tumour-initiating and metastatic capacity in vivo. PDXs showed much higher degree of infiltrative growth and distant metastasis as compared to neuroblastoma SK-N-BE(2)c cell line-derived orthotopic tumours. Importantly, the PDXs presented with bone marrow involvement, a clinical feature of aggressive neuroblastoma. Thus, neuroblastoma PDXs serve as clinically relevant models for studying and targeting high-risk metastatic neuroblastoma.What's new?Neuroblastoma is a childhood tumour with heterogeneous characteristics and children with metastatic disease have a poor outcome. Here, the authors established neuroblastoma patient-derived xenografts (PDXs) by orthotopic implantation of viably cryopreserved or fresh tumour explants of patients with high-risk neuroblastoma into immunodeficient mice. The PDXs retained the genotype and phenotype of patient tumours and exhibited substantial infiltrative growth and metastasis to distant organs including bone marrow. PDX-derived neuroblastoma cells were expanded in vitro and retained tumourigenic and metastatic capacity in vivo. The PDXs may thus represent an important tool for investigating neuroblastoma growth and metastasis as well as drug targeting.

PI3K–mTORC2 but not PI3K–mTORC1 Regulates Transcription of HIF2A/EPAS1 and Vascularization in Neuroblastoma

“…The resulting tumors closely resemble clinical neuroblastomas, with widespread metastasis to clinically relevant sites. Compared with classical cell lines grown in vitro for decades that display genotypic and phenotypic alterations, neuroblastoma PDXs retain the characteristics of the tumors from which they were derived (27). In addition, in vitro-cultured neuroblastoma PDX-derived cells retain their tumorigenic and metastatic capacity upon orthotopic injection into mice (27).…”

“…Compared with classical cell lines grown in vitro for decades that display genotypic and phenotypic alterations, neuroblastoma PDXs retain the characteristics of the tumors from which they were derived (27). In addition, in vitro-cultured neuroblastoma PDX-derived cells retain their tumorigenic and metastatic capacity upon orthotopic injection into mice (27). PDX-based tumor models are increasingly being used in cancer research for drug screening and testing of novel therapeutic targets due to being more predictive of clinical outcome than cell line-derived xenografts (47).…”

“…27. Dissociated cells were treated with LY294002 or PP242 at T ¼ 0 and T ¼ 24 hours and cultured at 21% or 1% oxygen levels for 48 hours in total.…”

“…27). Tumors growing in mice were resected, dissected, and grown in stem cell-promoting medium to allow the cells to grow as neurospheres (27). Importantly, these cells demonstrated hypoxia-induced HIF2A mRNA expression (Fig.…”

The role of mouse models in translational cancer research: present and future directions

“…In particular, the use of Fluorodeoxyglucosepositron emission tomography (FDG-PET) and an approach which combines micro PET and F(ab')2 fragments of the fullyhuman anti-EGFR monoclonal antibody, panitumumab, have been successfully evaluated. 28,29 Moreover, a fluorescently-labelled chimeric anti-CEA antibody was able to detect the primary tumor and the residual mass after the surgical resection in whole colon cancer PDOXs. 30 …”