Mesothelioma tumor cells modulate dendritic cell lipid content, phenotype and function

Area of Science:

• Immunology
• Oncology
• Cell Biology

Background:

• Dendritic cells (DCs) are crucial for anti-cancer immunity but are often dysfunctional in cancer patients.
• Tumor-associated lipid accumulation is a known cause of DC dysfunction in some cancers, but its role in mesothelioma is unexplored.

Purpose of the Study:

• To investigate whether mesothelioma cells and their secreted factors induce lipid accumulation and dysfunction in DCs.
• To determine the impact of lipid accumulation on DC function, including antigen processing and immune cell activation.

Main Methods:

• Human monocyte-derived DCs (MoDCs) were incubated with mesothelioma cells and/or tumor-derived factors, with or without lipoproteins.
• DC lipid content, antigen processing (DQ OVA assay), co-stimulatory molecule expression (CD86), and cytokine production (IL-10) were analyzed.
• In vivo studies utilized a murine mesothelioma model to assess DC lipid content and T cell proliferation in tumor-draining lymph nodes.

Main Results:

• Mesothelioma cells and factors increased lipid levels in MoDCs, impairing antigen processing and upregulating CD86 and IL-10.
• Lipid accumulation was exacerbated by co-exposure to mesothelioma factors and triglyceride-rich lipoproteins.
• Tumor progression in mice correlated with increased lipid content in tumor-infiltrating DCs and reduced proliferation of tumor-specific CD8+ T cells.

Conclusions:

• Mesothelioma promotes lipid acquisition by DCs, leading to altered activation and impaired antigen presentation.
• This lipid-induced DC dysfunction may compromise the generation of effective anti-mesothelioma T cell responses.