Cancer ResearchScientists Find How to Stop Cancer-Fighting T Cells From Burning Out
Cancer immunotherapy often fails because T cells — the immune system's cancer killers — become exhausted before finishing the job. Researchers at Memorial Sloan Kettering Cancer Center have identified MEK, a signaling molecule, as a key driver of this burnout. When T cells are constantly stimulated by tumor antigens, MEK ramps up production of cancer-killing proteins, which drains cellular energy and pushes the cells into a terminal exhausted state. Surprisingly, exhausted T cells were metabolically hyperactive, not sluggish. Blocking MEK in animal and lab studies caused T cells to multiply more while consuming less energy, keeping them functional longer in the harsh tumor environment. Because FDA-approved MEK inhibitors already exist, human trials could begin relatively quickly, potentially improving multiple forms of immunotherapy including checkpoint inhibitors.
