Nanoparticle-formulated mRNA encoding engineered multivalent SIRPα-Fc fusion proteins shows robust anti-cancer...

Area of Science:

• Biotechnology
• Immunotherapy
• Molecular Medicine

Background:

• mRNA therapeutics offer a novel way to express complex proteins in vivo.
• Targeting CD47 is a promising immunotherapy strategy for cancer.
• Multivalency can enhance specificity and efficacy of therapeutic proteins.

Purpose of the Study:

• To engineer multivalent SIRPα-Fc fusion proteins for enhanced CD47 targeting.
• To evaluate the in vitro and in vivo efficacy and safety of these mRNA-delivered therapeutics.
• To assess the characteristics of in vivo expressed proteins.

Main Methods:

• Formulation of mRNA encoding Tetravalent and Octavalent SIRPα-Fc fusion proteins.
• In vitro analysis of NK-mediated cytotoxicity and red blood cell binding.
• In vivo studies using Raji mice xenografts to assess tumor eradication.
• Characterization of in vivo expressed proteins for purity, stability, and aggregation.

Main Results:

• Tetravalent and Octavalent SIRPα showed comparable NK-mediated cytotoxicity to affinity-improved versions.
• These multivalent constructs exhibited minimal binding to red blood cells, unlike other anti-CD47 agents.
• Complete eradication of established subcutaneous tumors was observed in vivo.
• In vivo expressed proteins demonstrated high purity, excellent thermal stability, and resistance to aggregation.

Conclusions:

• Engineering complex multivalent molecules via mRNA delivery significantly enhances therapeutic window and efficacy.
• This approach offers a promising strategy for developing safer and more effective cancer immunotherapies.
• Multivalency is a key design principle for improving CD47-targeted therapeutics.