Synergistic effects of combined immunotherapy strategies in a model of multifocal hepatocellular carcinoma
María C. Ochoa, Sandra Sánchez‐Gregorio, Carlos E. de Andrea, Saray Garasa, Maite Álvarez, Irene Olivera, Javier Glez‐Vaz, Carlos Luri‐Rey, Iñaki Etxeberría, Assunta Cirella, Arantza Azpilikueta, Pedro Berraondo, Josepmaria Argemí, Bruno Sangro, Álvaro Teijeira, Ignacio Melero
Abstract
Immune checkpoint-inhibitor combinations are the best therapeutic option for advanced hepatocellular carcinoma (HCC) patients, but improvements in efficacy are needed to improve response rates. We develop a multifocal HCC model to test immunotherapies by introducing c-myc using hydrodynamic gene transfer along with CRISPR-Cas9-mediated disruption of p53 in mouse hepatocytes. Additionally, induced co-expression of luciferase, EGFP, and the melanosomal antigen gp100 facilitates studies on the underlying immunological mechanisms. We show that treatment of the mice with a combination of anti-CTLA-4 + anti-PD1 mAbs results in partial clearance of the tumor with an improvement in survival. However, the addition of either recombinant IL-2 or an anti-CD137 mAb markedly improves both outcomes in these mice. Combining tumor-specific adoptive T cell therapy to the aCTLA-4/aPD1/rIL2 or aCTLA-4/aPD1/aCD137 regimens enhances efficacy in a synergistic manner. As shown by multiplex tissue immunofluorescence and intravital microscopy, combined immunotherapy treatments enhance T cell infiltration and the intratumoral performance of T lymphocytes.