Senescent Cell-Derived Extracellular Vesicles Inhibit Cancer Recurrence by Coordinating Immune Surveillance.

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Cellular senescence is a state cancer cells enter to evade therapy.
• Senescent cells secrete extracellular vesicles (EVs) that mediate intercellular communication.
• The role of senescent cell (SC)-derived EVs (senEVs) in immune responses to senescence requires further investigation.

Purpose of the Study:

• To investigate the role of senEVs in triggering inflammatory responses and immune-mediated clearance of senescent cancer cells.
• To elucidate the mechanisms by which senEVs interact with immune cells and influence the tumor microenvironment.

Main Methods:

• Developed an engraftment-based senescence model in wild-type mice.
• Genetically blocked senEV release in vivo to assess its impact on immune responses.
• Performed comprehensive transcriptional and proteomic analyses to identify senEV ligands.
• Utilized flow cytometry and T-cell assays to analyze immune cell recruitment and activation.

Main Results:

• SenEVs were both necessary and sufficient to trigger immune-mediated clearance of SCs, suppressing tumor growth.
• Blocking senEV release impaired the recruitment of antigen-presenting cells (APCs) and redirected SC signaling towards neutrophils.
• SenEVs were found to promote APC-T cell adhesion and synapse formation, activating TH17 cells.
• CD4+ T cells were essential for preventing tumor recurrence, with senEVs enhancing their activation.

Conclusions:

• SenEVs play a critical role in orchestrating immune responses against senescent cancer cells, complementing soluble factors.
• SenEVs enhance the recruitment and activation of specific immune cell subsets, leading to efficient SC clearance and suppression of tumor recurrence.
• These findings have implications for understanding cancer recurrence and developing novel cancer detection and treatment strategies based on senescence biology.