A. M. Ibarra1,2, S. E. Woodfield1,2, R. H. Patel1,2, S. F. Sarabia1,2, K. B. Ghaghada1,2, D. Lopez-Terrada1,2, S. A. Vasudevan1,2 1Baylor College Of Medicine,Surgery/Pediatrics,Houston, TX, USA 2Texas Children’s Hospital,Surgery/Pediatrics,Houston, TX, USA
Introduction:
Hepatoblastoma (HB) is the most common pediatric liver malignancy with most patients under the age of five. Patients have an overall survival (OS) rate of 80% at five years after diagnosis; however patients with high-risk, metastatic disease have a five-year OS of only about 40%. There are currently no cell line xenograft models of aggressive, high-risk HB available for preclinical testing.
Methods:
Two million HepT1 cells were orthotopically injected into the livers of immunocompromised mice (NSG) to generate intrahepatic tumors. Growth of tumors in vivo was monitored with ELISA for levels of serum human α-fetoprotein (AFP), MRI, and bioluminescent imaging (BLI) as the HepT1 cell line was transduced with luciferin and emitted a signal with intraperitoneal injection of luciferase. We also analyzed cell line DNA for the described mutations, CTNNB1 (aa5-80 (exon 3)) and NFE2L2 (c.89T>C).
Results:
We injected 9 mice with HepT1 cells that were confirmed to have the CTNNB1 and the aggressive NFE2L2 mutations. Two out of 9 mice (22%) grew tumor within the first 2 weeks after implantation, and after 4 weeks, we had 100% take of HepT1 tumors in animals. Serum human AFP increased in the animals with the growth of tumors. Most importantly, we saw clear presence of vena caval tumor thrombus, extrahepatic disease including periportal lymph nodes, and lung metastasis in 75% of animals harboring HepT1 tumors.
Conclusion:
Building on our previous work developing orthotopic xenograft mouse models of HB with the widely available HepG2 and Huh-6 cell lines (Woodfield et al., 2017), we developed a more aggressive orthotopic xenograft mouse model of HB with intrahepatic injection of HepT1 cells. The tumors generated with this cell line were found to invade major blood vessels and metastasize, unlike other previously described cell line models of HB. This model will facilitate pre-clinical studies of aggressive HB.