Consolidation of a preclinical platform combining fluorescent live cell imaging and fresh human organotypic cultures to access potency and toxicity of CAR-T cells against solid tumors

Abstract

The therapies based on synthetic biology to modify T cell to express chimeric antigen receptor (CAR) have emerge as a revolutionary approach to treat hematological malignancies, and now are established as a treatment for relapse and/or refractory patients. However, the therapeutic efficacy of CAR-T cells is still low against solid tumors. The treatment of solid tumors with CAR-T cells is challenging due to the complex tumor microenvironment that impairs infiltration and persistence of injected cells. To overcome this challenge, it is essential to have desirable features such as potent activation and prolonged persistence, which are closely linked to the T cell differentiation state. Nevertheless, the ex vivo expansion during the CAR-T cell manufacturing affects T cell stemness leading to dysfunctionalities. Another critical limitation involves on-target off-tumor toxicity, the killing of healthy cells by engineered T cells, which can drive to severe and potentially life-threatening side effects. The lack of reliable and predictive preclinical platforms to better understand CAR-T cell behavior against tumor and healthy tissues poses a significant obstacle to the successful implementation of this therapeutic strategy. The typical characterization of CAR-T cells is primarily conducted through flow cytometry and transcriptome profiling. However, these techniques do not encompass the spatial and kinetic aspects of T cell responses within the microenvironment. Thus, we propose a preclinical platform combining advanced live imaging techniques and fresh human tissues slices to elucidate the dynamics of different states of differentiation of T cells and predict on-target off-tumor effects. (AU)