New Discoveries in Cancer Immunotherapy

Researchers at The Ohio State University Comprehensive Cancer Center have conducted a notable study shedding light on how immune systems respond to stress from misfolded proteins. This research, which could change cancer immunotherapy practices, points to innovative strategies targeting the protein production process.

A central question driving this study was why T cells, essential for fighting infections and recognizing cancer, sometimes become “exhausted” and lose their effectiveness.

The researchers discovered an unexpected vulnerability in these exhausted T cells: they are overwhelmed by misfolded proteins that trigger a newly identified stress response pathway, dubbed TexPSR (proteotoxic stress response in T-cell exhaustion).

Rather than slowing protein production to restore balance—as is typical in stress responses—TexPSR ramps up protein synthesis. This leads to an accumulation of misfolded proteins and toxic aggregates, resembling the amyloid plaques associated with Alzheimer’s disease. This overload has a detrimental effect on T cells, hampering their ability to combat tumors.

Nature Reviews Immunology referred to this situation as a “proteotoxic shock.” Notably, when researchers inhibited key components of TexPSR in their models, exhausted T cells were able to regain their function, and cancer immunotherapy showed significantly enhanced effectiveness.

“T-cell exhaustion poses a significant challenge in cancer immunotherapy. Our findings offer a surprising and promising solution to this persistent issue, potentially advancing engineered cancer therapies aimed at leveraging the immune system,” stated Zihai Li, MD, PhD, a senior author of the study and founding director of the Pelotonia Institute for Immuno-oncology at OSUCCC – James.

Li, who has researched the connection between protein folding and immunity for over thirty years, noted that while many researchers have focused on genetics and metabolism in relation to T-cell exhaustion, the aspect of protein quality control had been largely overlooked until now.

The Ohio State team also identified that elevated levels of TexPSR in T cells from cancer patients were associated with poor responses to immunotherapy, suggesting that targeting TexPSR might be a new avenue for improving treatment outcomes.

“When T cells are exhausted, they produce molecular weapons but essentially sabotage their own efforts before those weapons can be effective,” explained Yi Wang, the lead author and a doctoral student in Li’s lab.

This research highlights the self-perpetuating cycle of protein stress driving T-cell exhaustion, which ultimately impairs the function of these immune cells. Importantly, the mechanism was confirmed across multiple cancer types, including lung, bladder, liver cancers, and leukemia, underscoring its wide-ranging implications.

The full findings are reported in the latest issue of Nature.