Enhancing CAR T Cells with a Novel CRISPR Screening Platform

Researchers at the CeMM Research Center for Molecular Medicine and the Medical University of Vienna have developed a novel CRISPR screening platform, CELLFIE, to systematically discover genetic modifications that improve the function of CAR T cells. CAR T cell therapy has shown success in treating certain blood cancers but often fails due to intrinsic dysfunctions within the T cells. CELLFIE enables researchers to screen thousands of gene knockouts simultaneously to identify which genes enhance CAR T cells’ therapeutic potential.

Using the platform, they discovered that knocking out the gene RHOG significantly boosts CAR T cell effectiveness against leukemia in preclinical mouse models. Although RHOG is important in natural immune responses, it limits the potency of engineered CAR T cells. Removing this gene allowed the CAR T cells to expand more, resist exhaustion, and better control leukemia.

Further studies revealed that knocking out both RHOG and another gene, FAS, resulted in synergistic improvements. CAR T cells lacking both genes proliferated faster, remained more active, were less prone to killing each other, and cured mice with aggressive leukemia more effectively than standard CAR T cells.

The CELLFIE platform combines high-content CRISPR screening with CAR T cell engineering to enable comprehensive, rapid testing of genetic modifications. This flexible approach supports both in vitro and in vivo screens, combinatorial knockouts, and base editing, providing a versatile toolkit for advancing cell-based immunotherapies. 

This approach has the potential to generate CAR T cells with improved persistence, reduced side effects, and expanded therapeutic applications beyond blood cancers to solid tumors, autoimmune diseases, and regenerative medicine.

Christoph Bock, senior author of the paper published in Nature, emphasized, “Our study establishes an exciting candidate for future clinical validation as a therapy for certain blood cancers. And we created a broadly applicable method for the systematic enhancement of cell-based immunotherapies. We are learning how to program cells as effective cancer therapeutics and as ‘living medicines’ for a wide range of diseases.”