Enhancing the potency of CAR-T cells against solid tumors through transcription factor engineering

Abstract

Transcription factors (TFs) play a pivotal role in the development and differentiation of T cells. Recent studies have highlighted unique transcriptional profiles in chimeric antigen receptor T (CAR-T) cells derived from patients with favorable clinical outcomes, suggesting a potential link between TF modulation and improved therapeutic efficacy. Although CAR-T cell therapies have shown some success in treating hematological malignancies, they are limited by challenges such as poor persistence, functional exhaustion, and tumor resistance. To overcome these limitations, researchers have attempted to enhance the efficacy of CAR-T cells through manipulation of TF expression. This Review provides a comprehensive overview of TF engineering in CAR-T cells and elucidates the complex regulatory network between TFs. Notably, modification of basic leucine zipper ATF-like transcription factor in CAR-T cells results in contradictory functional outcomes in different studies. We summarize the potential factors leading to such results and elucidate the importance of setting up a relevant in vitro model to evaluate the effect of TFs on CAR-T cells. In conclusion, this Review highlights the latest advances in TF modifications and proposes strategies for harnessing these insights to empower CAR-T cells with superior antitumor efficacy.

Figure 1. Overview of the transcriptional regulatory networks that drive CAR-T cell differentiation into exhaustion and memory states.

A complex transcriptional program regulates CAR-T cell plasticity. Memory differentiation is driven by the regulation of FOXO1 and BLIMP and the downstream TCF1. RUNX3, FOXP1, KLF2, and KLF7 also promote memory T cell differentiation by activating the memory program. The canonical exhaustion pathway involves the NFAT-TOX/NR4A axis. NFAT can also cooperate with BATF, IRF4, and EGR2. CAR-T cells with a 4-1BB costimulatory domain exhibit a NK-like exhausted phenotype via the regulation of ID3 and SOX4. In addition, mechanical stress induces T cell exhaustion through the CREB/OSR2 pathway. IL7R, interleukin-7 receptor; LAG3, lymphocyte activation gene 3.

Figure 2. Distinct antitumor effects of BATF and IRF4 manipulation under different effector-to-target ratios.

BATF and IRF4 are ambivalent TFs that can contribute to either effector or exhaustion programs in CAR-T cells. Under high effector-to-target (E:T) ratios, overexpression of BATF and IRF4 boosts CAR-T cell proliferation and enhances antitumor efficacy. Conversely, the overexpression of BATF leads to exhaustion, while BATF KO enhances efficacy and alleviates exhaustion under low E:T ratios.

Figure 3. Strategies for TF manipulation to augment CAR-T cell antitumor activity.

This figure provides a perspective on the optimization of TF manipulation. Current combined manipulation includes plasmid-based overexpression (OE), CRISPR/Cas9 knockout (KO)/knockin (KI), and Cre-loxp gene-disrupted mice. Conditional manipulation is another strategy, including (a) “Hit-and-Run” strategy, which utilizes T cell–targeted nanocarriers to transiently express TFs, and (b) “Uni-Vect” system, which induces TF expression only when NFAT-driven signaling is activated. Analyzing the transcriptomic profile of preinfusion CAR-T cells may predict clinical outcomes and patient survival in CAR-T cell therapy. TKO, triple knockout.