Mechanoimmunological Control of Metastatic Site Selection.

Area of Science:

• Biophysics
• Immunology
• Cancer Biology

Background:

• Cancer cells exhibit phenotypic plasticity, altering mechanical properties in response to environmental cues.
• Environmental rigidity influences cancer cell behavior, with implications for tumor progression and immune evasion.

Purpose of the Study:

• To investigate how cancer cell mechanosensing of environmental rigidity impacts anti-tumor immunosurveillance.
• To elucidate the role of Osteopontin in mediating environmentally induced cell stiffening and immune sensitization.

Main Methods:

• Single-cell biophysical profiling to assess cancer cell mechanical properties.
• Development and utilization of metastasis models in immunodeficient and immunocompetent mice.
• Analysis of patient metastatic tissues to correlate environmental rigidity, immune infiltration, and cancer cell stiffness.

Main Results:

• Cancer cells stiffened in more rigid environments, increasing their susceptibility to cytotoxic lymphocytes.
• In immunocompetent hosts, increased cancer cell stiffness led to preferential elimination and suppressed bone metastasis.
• Environmentally induced cell stiffening and immune sensitization were dependent on Osteopontin, a glycoprotein upregulated during bone colonization.
• Patient data showed associations between tissue rigidity, immune cell infiltration, and cancer cell stiffness, supporting mechanically driven immunosurveillance.

Conclusions:

• Environmental mechanosensing by cancer cells significantly modulates anti-tumor immunity.
• Cellular stiffening in rigid environments enhances immune recognition and elimination of cancer cells.
• A mechanoimmunological mechanism underlies the selection of metastatic sites, with Osteopontin playing a crucial role.