Adenosine limits the therapeutic effectiveness of anti-CTLA4 mAb in a mouse melanoma model
Raffaella Iannone1, Lucio Miele2, Piera Maiolino3
1Department of Pharmacy, University of Salerno Italy.
Abstract:
Combination therapies for melanoma that target immune-regulatory networks are entering clinical practice, and more are under investigation in preclinical or clinical studies. Adenosine plays a key role in regulating melanoma progression. We investigated the effectiveness of cytotoxic T lymphocyte-associated antigen 4 (CTLA-4) antibody (mAb) in combination with either modulators of adenosine receptors (AR) activation or an inhibitor of adenosine production in a murine model of melanoma. We found that treatment with APCP, selective inhibitor of the adenosine-generating nucleotidase CD73, enhanced the activity of anti-CTLA4 mAb, by improving tumor immune response. Blockade of the adenosine A2a receptor (A2aR), which plays a critical role in the regulation of T-cell functions, significantly reduced melanoma growth. Most importantly, combination therapy including an A2aR antagonist with anti-CTLA4 mAb markedly inhibited tumor growth and enhanced anti-tumor immune responses. Targeting A3R and CTLA4 was not as effective in limiting melanoma growth as targeting A2aR. These data suggest that the efficacy of anti-CTLA4 melanoma therapy may be improved by targeting multiple mechanisms of immune suppression within tumor tissue, including CD73 or A2a receptor.
Insights
Combining CTLA-4 antibody therapy with adenosine receptor blockers or CD73 inhibitors can improve melanoma treatment. Targeting the adenosine A2a receptor alongside CTLA-4 antibody therapy significantly inhibited tumor growth in a mouse model.
Area of Science:
- Immunology
- Oncology
- Pharmacology
Background:
- Adenosine signaling influences melanoma progression and immune evasion.
- Immune checkpoint inhibitors like anti-CTLA-4 antibody are emerging therapies for melanoma.
- Targeting adenosine pathways offers a potential strategy to enhance anti-tumor immunity.
Purpose of the Study:
- To evaluate the efficacy of combining anti-CTLA-4 antibody therapy with modulators of adenosine receptors or adenosine production in a murine melanoma model.
- To determine the impact of targeting adenosine A2a receptor (A2aR) or CD73 on anti-tumor immune responses and melanoma growth.
Main Methods:
- Utilized a murine model of melanoma.
- Administered anti-CTLA-4 antibody in combination with CD73 inhibitors (APCP) or adenosine receptor antagonists (A2aR, A3R).
- Assessed tumor growth, anti-tumor immune responses, and the effectiveness of different combination strategies.
Main Results:
- Treatment with APCP enhanced the efficacy of anti-CTLA-4 antibody by improving the tumor immune response.
- Blockade of the adenosine A2a receptor significantly reduced melanoma growth.
- Combination therapy with an A2aR antagonist and anti-CTLA-4 antibody markedly inhibited tumor growth and boosted anti-tumor immunity.
- Targeting A3R with CTLA-4 was less effective than targeting A2aR.
Conclusions:
- Combination therapy targeting multiple immune suppression mechanisms, such as CD73 or A2aR, alongside anti-CTLA-4 antibody can improve melanoma treatment outcomes.
- Targeting the adenosine A2a receptor is a promising strategy to enhance the efficacy of anti-CTLA-4-based melanoma therapies.
