In the realm of cellular therapies, groundbreaking advancements have propelled treatments from theoretical concepts to clinical realities. Over the past decade, two pivotal technologies, chimeric antigen receptors (CAR) and genome editing, have spearheaded the development of revolutionary CAR T cell therapies for leukemia and lymphoma. These therapies, engineered through virus-mediated gene insertion ex vivo, empower T cells with synthetic receptors to recognize and eliminate tumor-specific antigens post-transplantation.

While genome editing, particularly utilizing clustered regularly interspaced short palindromic repeats (CRISPR), has shown promise in enhancing CAR T cell therapies, it also presents unique challenges. The permanent nature of DNA editing poses safety and efficacy concerns, prompting the need for innovative solutions. Addressing this need, bioengineer Lei (Stanley) Qi and physician immunologist Crystal Mackall at Stanford University have introduced multiplexed effector guide arrays (MEGA), an RNA editing tool designed to circumvent the limitations of DNA editing.

Published in Cell, their study showcases MEGA’s ability to utilize Cas9’s counterpart, Cas13, along with a pooled array of guide RNAs, to edit multiple gene transcripts in primary human T cells without altering genomic DNA. This groundbreaking approach enables dynamic regulation of multiple pathways within T cells, offering a significant advancement in cell therapy optimization. By screening for genes affecting T cell function and suppressing redundant transcripts linked to T cell exhaustion, MEGA demonstrates its potential to enhance therapeutic outcomes.

MEGA’s efficacy was validated through various experiments, including targeting multiple inhibitors of T cell function simultaneously, uncovering new genetic regulators, and enhancing CAR T cell activity in cancer models. The tool’s versatility and precision herald a new era in genome engineering, complementing existing DNA-targeting CRISPR technologies.

Neville Sanjana, a bioengineer at New York University, lauds MEGA’s contributions, emphasizing the importance of a comprehensive genome engineering toolbox. While DNA-targeting CRISPR has paved the way for transformative advancements, RNA editing offers unique advantages, including reversibility and minimal genomic impact. The ability to modulate gene expression in multiplexed ways represents a paradigm shift in cellular therapy research, promising a future of enhanced precision and efficacy.

By Impact Lab