Single Protein Discovery Could Unlock More Effective CAR T-Cell Cancer Therapy

Scientists have identified a single protein that may be one of the biggest obstacles preventing CAR T-cell therapy from reaching its full potential against cancer. Researchers from Columbia University and University Hospital Tübingen discovered that a protein called NFIL3 causes these engineered immune cells to become exhausted and lose their cancer-fighting effectiveness over time, but disabling this protein allows the cells to remain active longer and control tumors more effectively.

The breakthrough addresses a major limitation of CAR T-cell therapy, one of the most advanced forms of personalized cancer treatment. While the approach has produced remarkable results for blood cancers by genetically modifying patients' immune cells to recognize and destroy tumor cells, it has been far less successful against solid tumors. The international research team, led by Prof. Michel Sadelain at Columbia University and Prof. Judith Feucht at University Hospital Tübingen, set out to understand why these limitations exist.

To identify factors that weaken CAR T-cell performance, researchers conducted a comprehensive analysis of roughly 400 transcription factors, proteins that control gene activation within cells. Their investigation pointed to NFIL3 as a major contributor to CAR T-cell exhaustion, the process by which these therapeutic cells gradually lose their ability to function effectively against cancer. When researchers used CRISPR gene-editing technology to disable NFIL3, the modified CAR T cells maintained stronger anti-tumor effects for longer periods.

The benefits of removing NFIL3 were demonstrated across multiple mouse models, where CAR T cells lacking the protein proved more effective at controlling tumors and extending survival. Prof. Feucht explained that "switching off NFIL3 could be a decisive step toward significantly improving the long-term potency of CAR T cells," particularly for treating solid tumors that have proven resistant to current approaches.

Published in Cancer Discovery, the findings suggest a clear path toward enhancing CAR T-cell therapy effectiveness. Co-first author Celina May noted that the research team expects these discoveries "to open up new possibilities in the treatment of cancer patients." The work represents a convergence of cutting-edge cancer research and clinical care, as Prof. Feucht combines laboratory research with direct patient treatment within Germany's premier oncology research cluster.