Statins May Enhance Cancer Immunotherapy by Blocking Immune Suppression

A common and affordable medication, statins, may significantly improve the effectiveness of cancer immunotherapy by disrupting a newly discovered mechanism that allows cancer cells to evade the immune system. Researchers have identified a key protein, UBL3, that cancer cells use to package and release immune-suppressing signals, and statins have been shown to block this process.

The Challenge with Cancer Immunotherapy

Cancer immunotherapy, which harnesses the body’s own immune system to fight tumors, has revolutionized cancer treatment. Immune checkpoint inhibitors (ICIs), targeting the PD-1/PD-L1 pathway, have demonstrated lasting responses in some patients. Still, a significant limitation is that many tumors develop resistance, finding ways to escape immune detection. This has prompted researchers to investigate broader mechanisms of immune resistance beyond the tumor itself, focusing on how cancers suppress immune activity throughout the body.

How Cancer Cells Evade the Immune System

Recent research has highlighted the role of small extracellular vesicles (sEVs) released by cancer cells. These tiny particles carry immunosuppressive molecules, weakening the immune response and reducing the effectiveness of immunotherapy. A key molecule carried within these vesicles is PD-L1, which suppresses the activity of T cells, a crucial component of the immune system.

The Role of UBL3 in PD-L1 Packaging

Scientists at Fujita Health University in Japan, led by Professor Kunihiro Tsuchida, discovered that a protein called ubiquitin-like 3 (UBL3) plays a critical role in directing PD-L1 into sEVs. They found that UBL3 controls a unique post-translational modification of PD-L1, enabling its packaging into vesicles. Increasing UBL3 levels led to more PD-L1 inside vesicles, while reducing UBL3 expression decreased PD-L1 packaging and release. ¹

Statins Interfere with Immune Suppression

Remarkably, the research team found that statins, commonly prescribed to lower cholesterol, strongly inhibit UBL3 modification. All clinically used statins tested suppressed UBL3 activity, reducing PD-L1 modification and its incorporation into sEVs, even at concentrations achievable in clinical settings. ¹

Clinical Evidence Supports the Findings

Analysis of serum samples from patients with non-small cell lung cancer revealed that those taking statins had significantly lower levels of PD-L1-containing sEVs compared to those not using statins. Combined expression levels of UBL3 and PD-L1 were associated with survival outcomes in lung cancer patients, suggesting the clinical relevance of this pathway. ¹

Implications for Immunotherapy

These findings offer a potential strategy to overcome resistance to cancer immunotherapy. By disrupting the UBL3-mediated packaging of PD-L1 into sEVs, statins could reduce the amount of immunosuppressive signals circulating in the body, allowing immunotherapy to work more effectively. ² Adding statins to combination treatment approaches may offer a practical and scalable way to improve outcomes for patients receiving immune checkpoint blockade.

Further Research and Future Directions

The researchers suggest that this discovery could lead to more effective and accessible cancer immunotherapies, potentially improving survival and quality of life for patients. ¹ Further studies are needed to confirm these findings in larger clinical trials and to determine the optimal statin dosage and timing for combination therapy.

Reference: Ageta, H., Shimada, Y., Nagaoka, T., Takenaka, K., Yoshioka, Y., Konno, K., … & Tsuchida, K. (2025). Statins attenuate PD-L1 sorting to small extracellular vesicles dependent on ubiquitin-like 3 modification. Scientific Reports.