High-Integrity Nanoformulation of Resiquimod (R848) for Dual Autophagy Activation and PD-L1 Modulation in...

Area of Science:

• Nanotechnology
• Immunotherapy
• Oncology

Background:

• Triple-negative breast cancer (TNBC) presents significant treatment challenges due to its heterogeneity and therapy resistance.
• Developing effective drug delivery systems is crucial for improving immunotherapy efficacy in TNBC.

Purpose of the Study:

• To formulate and characterize high-integrity nanoemulsions (NEs) for enhanced delivery of resiquimod (R848), a Toll-like receptor 7/8 (TLR7/8) agonist.
• To evaluate the in vitro efficacy of R848-loaded NEs in TNBC cells, focusing on cellular uptake, molecular modulation, and potential synergistic effects.

Main Methods:

• Development of neutral and negatively charged NEs with and without ricinoleic acid for R848 encapsulation.
• Physicochemical characterization, including stability and protein binding assessments.
• In vitro studies using RAW 264.7 macrophages and 4T1 TNBC cells to assess cellular uptake and molecular changes (TLR4/7, Cyclin D1, NF-κB, autophagy markers, PD-L1).

Main Results:

• R848-loaded NEs demonstrated prolonged shelf-life, minimal protein binding, and efficient cellular uptake.
• Ricinoleic acid incorporation enhanced drug retention and delivery within the NEs.
• Molecular profiling revealed induction of autophagy and upregulation of PD-L1 expression in 4T1 cells, alongside modulation of key signaling pathways.

Conclusions:

• R848-loaded NEs offer a promising formulation for enhancing immunotherapy in TNBC.
• The dual action of inducing autophagy and modulating immune checkpoints suggests potential synergistic effects with anti-PD-L1 therapies.
• This approach provides a novel strategy for improving TNBC treatment outcomes.