Synthetic M13 phage engagers expand CAR-T cell antigen recognition to overcome tumor heterogeneity

Area of Science:

• Biotechnology
• Immunotherapy
• Oncology

Background:

• Chimeric antigen receptor T (CAR-T) cell therapy faces challenges in solid tumors due to tumor antigen heterogeneity and T cell inhibition.
• Existing CAR-T strategies struggle to effectively target diverse tumor cell populations and maintain T cell function.

Purpose of the Study:

• To develop a novel platform using bacteriophage-based bispecific engagers (BiPEs) to enhance CAR-T cell efficacy against solid tumors.
• To enable CAR-T cells to recognize multiple tumor antigens simultaneously and resist inhibitory signals.
• To provide a scalable and modular strategy for improving CAR-T therapy in solid tumors.

Main Methods:

• Engineered synthetic M13 bacteriophage-based bispecific engagers (BiPEs) by conjugating single-chain antibodies against distinct tumor targets onto phage pIII proteins using SpyTag-SpyCatcher technology.
• Developed M13 phage-specific CAR-T (MCAR-T) cells designed to recognize the engineered BiPEs.
• Utilized lipid nanoparticle-delivered MCAR mRNA for in vivo generation of functional CAR-T cells.

Main Results:

• BiPEs successfully redirected MCAR-T cells to eliminate heterogeneous tumor subclones in syngeneic glioblastoma models.
• MCAR-T cells treated with BiPEs demonstrated enhanced efficacy against antigenically diverse tumor cells, significantly prolonging survival compared to single-target CAR-T.
• In vivo administration of MCAR mRNA via lipid nanoparticles resulted in functional CAR-T cells with effective multitargeting capabilities.

Conclusions:

• The developed BiPE platform effectively overcomes tumor antigen heterogeneity and T cell inhibition in solid tumors.
• Programmable multitarget recognition by BiPEs enhances CAR-T cell function, leading to broad and durable tumor clearance.
• This modular bacteriophage-based approach offers a scalable strategy for advancing CAR-T therapy in solid tumors.