Cutaneous diffuse large B-cell lymphoma induces a macrophage immunosuppressive phenotype through IL-10 secretion

Area of Science:

• Oncology
• Immunology
• Cell Biology

Background:

• Primary cutaneous diffuse large B-cell lymphoma, leg type (PCDLBCL-LT) is a rare lymphoma subtype.
• PCDLBCL-LT shares genetic traits with other B-cell lymphomas and involves M2-polarized tumor-associated macrophages (TAMs).

Purpose of the Study:

• To investigate the mechanistic interplay between PCDLBCL-LT cells and macrophages.
• To identify key molecular mediators driving macrophage polarization in the PCDLBCL-LT microenvironment.

Main Methods:

• Utilized a unique PCDLBCL-LT cell line (ARSI) and co-culture systems with primary monocytes and THP-1 cells.
• Analyzed secretome for cytokines and chemokines, including IL-10.
• Investigated the effect of IL-10/IL-10RA blockade on macrophage polarization.
• Co-cultured macrophages with patient-derived xenografts and other DLBCL cell lines.
• Assessed macrophage impact on tumor cell proliferation and doxorubicin resistance.

Main Results:

• ARSI cells induced phenotypic, transcriptional, and functional changes in macrophages, independent of cell contact.
• Secretome analysis revealed high concentrations of IL-10, which mediated macrophage polarization.
• IL-10/IL-10RA blockade inhibited tumor-induced macrophage polarization.
• MYD88-mutated DLBCL cell lines showed similar macrophage-shaping effects, suggesting genetic specificity.
• Macrophages enhanced PCDLBCL-LT proliferation and doxorubicin resistance in co-culture.

Conclusions:

• The study confirms a robust model for investigating lymphoma-macrophage interactions.
• Highlights IL-10 as a critical factor in shaping the lymphoma microenvironment.
• Suggests that specific tumor cell genetics, not just location, drive macrophage interplay.
• Findings may inform the development of novel microenvironment-targeted therapies for PCDLBCL-LT.