Stage-specific CAR-mediated signaling generates naive-like, TCR-null CAR T cells from induced pluripotent stem cells.
Publication Year:
2024
PubMed ID:
39651198
Public Summary:
Exciting responses and cures have been seen by harnessing the T cells of the immune system to kill cancer using chimeric antigen receptors (CARs). However, the current methods to provide these “CAR-T cells” require the use of autologous T cells i.e. T cells harvested from the patient’s own blood. Not all patients who could benefit are able to access this therapy because of the cost and logistical challenges needed to manufacture unique products that must be created anew each time they are needed. In addition, the functional potency of autologous T cells is very unpredictable, leading to many treatment failures. We are tackling these issues by using induced pluripotent stem cells (iPSCs) to generate synthetic CAR-T cells. One major advantage of iPSC-derived CART cells is that complex gene editing can be used to improve function; in addition the modified iPSC can be expanded indefinitely providing an inexhaustible supply of cloned CART cells. A major problem however, is that T cells generated from iPSCs express receptors (TCRs) that can cause immune reactions in the patient unless they are modified. In the manuscript by Yoo et al, BioRxiv 2024, we used CRISPR-based gene editing combined with a novel culture system (the artificial thymic organoid aka ATO), to generate potent CAR-T cells that lack all T cell receptors (TCRs). This approach could provide a universal source of T cells that can carry different types of CARs.
Scientific Abstract:
Genetically modified, induced pluripotent stem cells (iPSCs) offer a promising allogeneic source for the generation of functionally enhanced, chimeric antigen receptor (CAR) T cells. However, the signaling of CARs during early T cell development and the removal of the endogenous T cell receptor required to prevent alloreactivity pose significant challenges to the production of mature conventional CAR T cells from iPSCs. Here, we show that TCR-null, CD8alphabeta CAR T cells can be efficiently generated from iPSCs by engineering stage-specific onset of CAR expression and signaling to both permit conventional T cell development and to induce efficient positive selection. CAR T cells produced using this approach displayed a uniform, naive T cell phenotype and demonstrated superior antigen-specific cytotoxicity compared to iPSC-derived effector memory CAR T cells. Multimodal sequencing revealed CAR-mediated positive selection induced the persistent upregulation of key transcription factors involved in naive T cell development. Achieving precise control of CAR expression and signaling in developmentally sensitive T precursors will be critical to realizing the full potential for "off-the-shelf", iPSC-derived cellular therapies.
