Synergistic effects of combined immunotherapy strategies in a model of multifocal hepatocellular carcinoma
Maria Carmen Ochoa 1 , Sandra Sanchez-Gregorio 2 , Carlos E de Andrea 3 , Saray Garasa 4 , Maite Alvarez 4 , Irene Olivera 4 , Javier Glez-Vaz 4 , Carlos Luri-Rey 4 , Iñaki Etxeberria 5 , Assunta Cirella 5 , Arantza Azpilikueta 4 , Pedro Berraondo 6 , Josepmaria Argemi 7 , Bruno Sangro 7 , Alvaro Teijeira 1 , Ignacio Melero 8
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.