STAT3 inhibition specifically in human monocytes and macrophages by CD163-targeted corosolic acid-containing...

Area of Science:

• Immunology
• Oncology
• Drug Delivery

Background:

• Tumor-associated macrophages (TAMs), particularly CD163-positive TAMs, are crucial in cancer immune suppression and linked to poor patient outcomes.
• STAT3 activation in the tumor microenvironment promotes an immunosuppressive TAM phenotype, making it a therapeutic target.
• Targeting TAMs directly offers a strategy to reduce systemic side effects associated with STAT3 inhibition.

Purpose of the Study:

• To develop and evaluate a novel drug that specifically inhibits STAT3 within TAMs by targeting the CD163 scavenger receptor.
• To assess the drug's ability to reprogram TAMs from an M2-like (tumor-supporting) to an M1-like (tumor-killing) phenotype.
• To investigate the drug's effect on STAT3-regulated gene expression and cytokine production in human macrophages.

Main Methods:

• Development of a CD163-targeted liposomal drug (CA-LCL-αCD163) encapsulating corosolic acid (CA).
• Inhibition of STAT3 phosphorylation in CD163-positive versus CD163-negative cells.
• Analysis of STAT3-regulated gene expression (IL-10, TNFα) and pro-inflammatory cytokine levels (IFNγ, IL-12, TNFα, IL-2).

Main Results:

• CA-LCL-αCD163 effectively inhibited STAT3 phosphorylation specifically in CD163-positive cells.
• The drug suppressed IL-10 expression and increased TNFα expression, indicating a shift towards a pro-inflammatory macrophage phenotype.
• Elevated levels of pro-inflammatory cytokines (IFNγ, IL-12, TNFα, IL-2) confirmed M1-like reprogramming at the mRNA level.

Conclusions:

• CD163-targeted liposomal corosolic acid (CA-LCL-αCD163) demonstrates specific inhibition of STAT3 in TAMs.
• The drug successfully reprograms human macrophages towards an M1-like phenotype, suggesting anti-cancer potential.
• These findings support further in vivo investigation of CA-LCL-αCD163 as a targeted cancer therapeutic.