Kiet Nguyen and Elizabeth Anne Kiely were hunched over their microscopes in a lab in College Park, watching something extraordinary unfold in real time: a purple CAR T-cell at the center of the frame, locked in battle with green tumor cells, ripping fragments from their surfaces like pieces of armor torn in combat. This vivid image, captured by the University of Maryland research team, is more than a scientific marvel—it’s a clue to a breakthrough that could transform cancer treatment. In a study led by Dr. Tim Luetkens and first author Kenneth Dietze at the University of Maryland School of Medicine in Baltimore, researchers discovered that blocking a protein called cathepsin b stops this fragment-stealing process, known as trogocytosis, and significantly boosts the cancer-fighting power of CAR T-cells. For patients battling recurrent or treatment-resistant blood cancers, this could mean longer remissions and stronger responses to one of the most advanced therapies available.
CAR T-cell therapy has been hailed as a revolution in oncology—genetically reprogramming a patient’s own immune cells to hunt down cancer has led to remarkable recoveries. Yet, more than half of patients relapse within five years, often because the engineered cells become exhausted or less effective. The Maryland team’s discovery sheds light on why: when CAR T-cells steal pieces of tumor cell membranes, they not only lose their targeting ability but may even begin to attack each other. By inhibiting cathepsin b, a protein involved in this transfer, the researchers saw CAR T-cells stay active longer and destroy tumors more efficiently in both lab cultures and animal models. The findings, published in Signal Transduction and Targeted Therapy, offer a clear path to enhancing an already powerful therapy.
The collaboration between the Luetkens lab at UMSOM and the Upadhyaya lab at the University of Maryland, College Park, was pivotal. Using lattice light sheet microscopy—one of the most advanced imaging techniques available—the team could observe these interactions in unprecedented detail. "This process makes the CAR T-cells less effective at attacking cancer," said Dr. Luetkens, who also directs research and development at the UMGCCC Fannie Angelos Cellular Therapeutics GMP Lab. Now, with a clear molecular target, the next step is human trials. The University of Maryland Greenebaum Comprehensive Cancer Center is already leading a first-in-human clinical trial for patients with difficult-to-treat B-cell lymphoma, opening the door to testing this enhancement in real patients.
While the journey from lab to clinic takes time, the implications are immediate: a simple molecular tweak could make a life-saving therapy last longer. As Dr. Taofeek K. Owonikoko, executive director of UMGCCC, put it, this is "real progress that could ultimately improve durability and outcomes for our patients." For the thousands facing relapsed blood cancers each year, that progress can’t come soon enough.