Project Abstract
The long-term goal of this project is to develop an adoptive immunotherapy with T cells expressing chimeric
antigen receptors (CARs) for recurrent and refractory pediatric sarcoma, which prognosis remains poor. CAR T
cell therapy has demonstrated success for hematological malignancies in clinical studies; however, CAR T cells
have been less effective for solid tumors in the clinic. While limited efficacy is multifactorial, a significant
roadblock for solid tumor CAR T cell therapy is the lack of targetable antigens. One prominent ECM protein is
tenascin C (TNC), and cancer cells, including sarcoma cells, express oncofetal tenascin C (TNC) spice
variants, which can contain an additional C domain (C.TNC). Since C.TNC expression correlates with the
malignant phenotype of cancer cells, we posit that it is an ideal CAR target. In support of this application, we
have generated a 2nd generation C.TNC-specific CAR with a CD28 costimulatory domain (C.TNC-CAR). I now
hypothesize that C.TNC-CAR T cells recognize and kill C.TNC-positive tumor cells and can be
optimized to have potent antitumor in preclinical pediatric sarcoma models. We have demonstrated in
preliminary studies that C.TNC-CAR T cells recognize and kill C.TNC+ sarcoma cell lines in vitro. In this project
now, we propose to investigate this hypothesis in two interrelated research aims. Aim 1 focuses on
understanding the mechanism of our ECM-targeting C.TNC-CAR T cells, and Aim 2 then compares the
effector function of C.TNC-CAR T cells in in vivo sarcoma xenograft models evaluating expansion,
persistence, and anti-tumor activity. Techniques to be employed include flow cytometry, ELISAs, co-cultures
and cytotoxicity assays, and CRISPR-Cas9 genome editing.
This project was designed to train me in techniques to generate and characterize genetically modified T cells
expressing CARs as well as introduce me into the evolving field of cancer cell therapy. This proposal and training
will be performed at St. Jude Children’s Research Hospital, an NCI-designated comprehensive cancer center. If
successful, the results of this proposal could have immediate applications for pediatric sarcomas. In addition, it
should have a significant impact on a broad range of other pediatric and adult solid tumors that also express
C.TNC.