Dynamic Immune Cell Composition, Phenotypes, and Signaling in an Engineered Metastatic Niche.

Area of Science:

• Oncology
• Immunology
• Biomaterials Science

Background:

• Metastasis significantly worsens breast cancer prognosis, but its timing and location are unpredictable.
• Current methods limit timely identification and treatment of metastatic disease.
• Understanding metastatic dormancy is crucial for improving patient outcomes.

Purpose of the Study:

• To investigate dynamic immune processes during metastatic progression using a synthetic niche.
• To understand the mechanisms underlying metastatic dormancy in breast cancer.
• To compare immune cell dynamics in a synthetic niche versus the native lung metastatic site.

Main Methods:

• Employment of a synthetic metastatic niche using a microporous scaffold.
• Infiltration of the scaffold with immune cells and recruitment of tumor cells.
• Analysis of immune cell phenotypes (neutrophils, monocytes, dendritic cells) and signaling pathways in the scaffold and lungs.

Main Results:

• The synthetic scaffold successfully recruits immune and tumor cells, mimicking metastatic sites.
• Immune cell phenotypes in the scaffold shift from anti-tumor to pro-tumor, mirroring lung dynamics but remaining less pro-tumor.
• Signaling pathways indicate macrophage involvement in early responses and neutrophils in later stages, correlating with stable tumor cell numbers (dormancy).

Conclusions:

• The synthetic niche effectively captures immune dynamics and signaling associated with metastatic progression and dormancy.
• This tool provides insights into the mechanisms driving stable tumor cell numbers in metastatic disease.
• The scaffold serves as a valuable model for investigating breast cancer metastasis and dormancy.