Autologous humanized mouse models of iPSC-derived tumors allow for the evaluation and modulation of cancer-immune cell interactions

Modeling the tumor-immune cell interactions in humanized mice is complex and limits drug development. Here, we generated easily accessible tumor models by transforming either primary skin fibroblasts or iPSC-derived cell lines injected in immune-deficient mice reconstituted with human autologous immune cells. Our results showed that either fibroblastic, hepatic or neural tumors were all efficiently infiltrated and partially or totally rejected by autologous immune cells in humanized mice. Characterization of tumor immune infiltrates revealed high expression levels of the dysfunction markers Tim3 and PD-1 in T cells and an enrichment in regulatory T cell suggesting rapid establishment of an immunosuppressive microenvironment. Inhibition of PD-1 by Nivolumab in humanized mice resulted in an increased immune cell infiltration and a slight decrease in tumor growth. We expect these versatile and accessible cancer models will facilitate preclinical studies and the evaluation of autologous cancer immunotherapies across a range of different tumor cell types. SIGNIFICANCE STATEMENT Preclinical models capable of providing an environment where human tumors are confronted with autologous immune cells are not easily accessible and limit drug development. As an alternative we generated genetically-defined tumor cell lines from primary and iPSC-derived cells for the evaluation of cancer-immune cell interactions in autologous humanized mice. ### Competing Interest Statement The authors have no conflicts of interest to disclose. C.R. and M.P. are co-founders, shareholders and officers of the regenerative medicine company Morphocell Technologies Inc.