Single Protein May Be Holding Back CAR T Cancer Therapy
Researchers identified NFIL3 as a major obstacle causing engineered immune cells to become exhausted and lose their cancer-fighting power, offering new hope for improving treatment of solid tumors.
Scientists from Columbia University and University Hospital Tübingen have identified a protein called NFIL3 that appears to play a major role in weakening CAR T cells over time, potentially explaining why this promising cancer therapy has struggled against solid tumors. The research team, led by Prof. Michel Sadelain at Columbia University and Prof. Judith Feucht at University Hospital Tübingen, found that disabling NFIL3 allowed these engineered immune cells to remain active longer and attack tumors more effectively in laboratory studies.
CAR T-cell therapy represents one of the most advanced forms of personalized cancer treatment, involving the collection of a patient's own immune cells, genetic modification to recognize cancer, and reinfusion to seek out and destroy tumor cells. While the therapy has produced remarkable results for some blood cancers, it has been far less successful against solid tumors, prompting researchers to investigate the underlying mechanisms that limit its effectiveness in these more challenging cases.
To identify factors that limit CAR T-cell performance, the international research team conducted a comprehensive analysis of roughly 400 transcription factors, proteins that control which genes are switched on or off inside cells. Their investigation pointed to NFIL3 as a major contributor to CAR T-cell exhaustion, a process in which the cells gradually lose their ability to function effectively over time. When researchers used CRISPR/Cas9 gene-editing technology to remove NFIL3, the CAR T cells stayed active for longer periods, multiplied more efficiently, and maintained stronger anti-tumor effects.
The benefits of removing NFIL3 were demonstrated across several mouse models, where CAR T cells lacking the protein proved more effective at controlling tumors and helped extend survival times. The results suggest a possible path toward improving treatment for cancers that currently respond poorly to CAR T-cell therapy, particularly solid tumors that have proven resistant to existing approaches. "Switching off NFIL3 could be a decisive step toward significantly improving the long-term potency of CAR T cells," explained Prof. Feucht.
The discovery could have significant implications for cancer patients who have exhausted other treatment options, as improved CAR T-cell therapy might offer new hope for those with solid tumors that have been largely untreatable with current immunotherapy approaches. The research team now plans to advance their findings toward clinical trials, where they can test whether disabling NFIL3 in human CAR T cells produces similar benefits for cancer patients. The work represents a crucial step in the ongoing effort to unlock the full potential of engineered immune cell therapies against the broadest possible range of cancer types.
