Reprogramming macrophage polarization with a small molecule G3I: Enhancing tumor suppression and inflammation control

Area of Science:

• Immunology
• Pharmacology
• Cancer Biology

Background:

• Glycogen synthase kinase-3β (GSK-3β) is crucial for regulating innate and adaptive immunity.
• Modulation of pro- and anti-inflammatory cytokines is a key function of GSK-3β.
• Understanding GSK-3β regulators in innate immunity is vital for therapeutic development.

Purpose of the Study:

• To develop small molecule inhibitors targeting GSK-3β's ATP-binding sites.
• To investigate the role of GSK-3β inhibitors in modulating macrophage polarization.
• To evaluate the therapeutic potential of identified inhibitors in cancer treatment.

Main Methods:

• Fragment-based de novo design (FBDND) was employed to create GSK-3β inhibitors.
• Macrophage polarization (M1/M2 markers), NF-κB activity, and cytokine production were assessed.
• In vitro assays evaluated the effects of G3I on tumor cell proliferation, migration, and macrophage phagocytic/cytotoxic activity.

Main Results:

• The inhibitor G3I modulated macrophage polarization, upregulating M1 markers (CD86, CCR7) and downregulating M2 markers (CD206, Arg-1, CCL18).
• G3I treatment decreased NF-κB activity and modulated cytokine production (TNF-α, IL-6, iNOS) via TLR4 signaling.
• G3I-treated M1 macrophages enhanced phagocytosis and cytotoxicity against tumor cells, while M2 macrophages showed reduced tumor cell migration.

Conclusions:

• G3I effectively regulates macrophage polarization balance within the tumor microenvironment.
• G3I enhances macrophage phagocytic and microbicidal activities, crucial for anti-tumor responses.
• G3I demonstrates potential as a novel therapeutic agent for cancer treatment through immune modulation.