Title:

Electroporation-based genetically engineered mouse models (EPO-GEMMs) as a versatile platform for evaluating efficacy and safety of CAR T cell therapy

Zeda Zhang^1,4, Clemens Hinterleitner¹, Xin Fang¹, Stella Paffenholz¹, Kaloyan Tsanov¹, Yu-jui Ho¹, Sascha Haubner², Friederike Kogel², Kevin Chen³, Wei Luan¹, Janelle Simon¹, Aveline Filliol¹, Elisa de Stanchina³, Judith Feucht⁴, Joseph Leibold⁴, Michel Sadelain², Scott W. Lowe^1,4,†

1. Cancer Biology and Genetics Program, Memorial Sloan Kettering Cancer Center, New York.
2. Immunology Program, Memorial Sloan Kettering Cancer Center, New York.
3. Antitumor Assessment Core Facility, Memorial Sloan Kettering Cancer Center, New York.
4. Cluster of Excellence iFIT, University Children’s Hospital Tübingen, Germany
5. Howard Hughes Medical Institute.

Abstract: 

Genetically engineered mouse models (GEMMs) have been pivotal in characterizing oncogenic mutations and evaluating experimental cancer therapies within native tissue contexts. However, the time and cost associated with GEMMs present challenges in rapidly investigating multiple cancer-causing mutations and therapeutic hypotheses. To address this issue, we developed a somatic tissue engineering platform known as electroporation-based genetically engineered mouse models (EPO-GEMMs). EPO-GEMMs allow us to efficiently introduce patient-relevant oncogenic mutations into various organs, resulting in the development of prostate, stomach, pancreas and ovarian tumors that faithfully replicate clinical and pathological features of human cancer.

One goal of our research is to test the suitability of our models for various preclinical applications.  In this regard, we have previously shown that the urokinase plasminogen activator receptor (uPAR) is overexpressed in senescent cells and across various cancer types including pancreas, bladder, brain and ovarian carcinomas. This finding prompted us to test whether our EPO-GEMM model would serve as a useful preclinical system for evaluating CAR T cell therapy targeting uPAR as a potential cancer treatment. Leveraging EPO-GEMM-derived ovarian tumors, we demonstrated the potent anti-tumor activities of murine uPAR CAR T cells in immunocompetent mice without inducing severe adverse effects. Subsequently, we launch an exhaustive functional screening of human uPAR single-chain fragment variants (scFVs). This screening resulted in the identification of lead scFVs with subnanomolar affinity. Remarkably, human uPAR CAR T cells are capable of eradicating both orthotopic and metastatic human ovarian cancer xenograft tumors. Our ongoing efforts include assessing the long-term safety and toxicity profiles of uPAR CAR T cells using a humanized model platform. These results constitute the proof-of-concept evidence of utilizing EPO-GEMMs to create patient-relevant tumors and evaluate the efficacy and safety of new targets for CAR T cell therapy in autochthonous an immunocompetent hosts.