In vitro 2D and 3D cancer models to evaluate compounds that modulate macrophage polarization

Area of Science:

• Oncology
• Immunology
• Drug Discovery

Background:

• Developing in vitro cancer models is crucial for identifying novel immunomodulating compounds.
• Tumor-associated macrophages (TAMs) play a significant role in cancer progression and immune evasion.
• Targeting TAMs offers a promising strategy for anti-cancer immunotherapy.

Purpose of the Study:

• To evaluate the efficacy of TAM-inhibiting and TAM-reprograming compounds using a 3D multicellular tumor spheroid (MCTS) model.
• To assess the impact of these compounds on monocyte infiltration and macrophage polarization within tumor spheroids.
• To establish a robust model for screening anti-cancer immunotherapies targeting macrophages.

Main Methods:

• Established a 3D MCTS model incorporating cancer cells, fibroblasts, and macrophages.
• Tested TAM-inhibiting compounds (CCL2 Ab, CSF1R inhibitor, CSF1R Ab) and TAM-reprograming compounds (poly I:C, CD40 Ab, CD40 ligand).
• Characterized macrophage polarization by measuring CD206, CD163, CD86, MHC II, CD40, and CD14 expression, and analyzed 43 soluble factors. Compared results with 2D macrophage models.

Main Results:

• A CSF1R inhibitor effectively prevented monocyte infiltration into pancreatic cancer spheroids.
• Macrophages treated with the CSF1R inhibitor exhibited reduced expression of M2 markers.
• Treatment with CD40 ligand and poly I:C induced M1 macrophage polarization in the 3D MCTS model.

Conclusions:

• The 3D MCTS model is a valuable tool for evaluating immunomodulating compounds targeting macrophages.
• This model can improve the drug screening process for anti-cancer immunotherapies.
• Targeting TAMs with specific inhibitors or reprogramming agents shows potential in modulating the tumor immune microenvironment.