Co-Targeting PD-1 and IL-33/ST2 Pathways for Enhanced Acquired Anti-Tumor Immunity in Breast Cancer

Area of Science:

• Immunology
• Oncology
• Cancer Research

Background:

• Breast cancer immunotherapy faces challenges despite advancements.
• Previous work demonstrated combined blockade of IL-33/ST2 and PD-1/PD-L pathways enhances natural killer (NK) cell antitumor capacity.
• The precise impact of this dual blockade on T lymphocytes and macrophages requires further elucidation.

Purpose of the Study:

• To investigate the specific effects of combined IL-33/ST2 and PD-1/PD-L pathway blockade on T lymphocyte and macrophage populations in a breast cancer model.
• To analyze changes in immune cell populations and activation markers within the tumor microenvironment and spleen.

Main Methods:

• A 4T1 breast cancer model was established in BALB/C and BALB/C ST2-/- mice.
• Mice received anti-PD-1 antibody treatment.
• Flow cytometry was used to analyze T cells and macrophages post-sacrifice, assessing markers like M1 macrophage percentage, CD86, TNFα, Interleukin-17, CD69, NKG2D, FasL, Interleukin-10, and FoxP3.

Main Results:

• Dual blockade significantly increased the proportion of M1 macrophages in the tumor microenvironment, with elevated CD86 and TNFα expression.
• Significant T cell accumulation was observed in both the spleen and tumor microenvironment.
• T cells exhibited increased activation markers (Interleukin-17, CD69, NKG2D, FasL) and decreased regulatory markers (Interleukin-10, FoxP3).

Conclusions:

• Combined blockade of PD-1/PD-L and IL-33/ST2 axes effectively re-establishes an anti-tumor immune response in breast cancer.
• This dual immunotherapy strategy shows promise for improving treatment outcomes in breast carcinoma by modulating T cell and macrophage functions.