Inducible expression of interleukin-12 augments the efficacy of affinity-tuned chimeric antigen receptors in murine
Yanping Yang1, Huan Yang2, Yago Alcaina1
1Molecular Imaging Innovations Institute, Department of Radiology, Weill Cornell Medicine, New York, NY, 10065, USA.
Abstract:
The limited number of targetable tumor-specific antigens and the immunosuppressive nature of the microenvironment within solid malignancies represent major barriers to the success of chimeric antigen receptor (CAR)-T cell therapies. Here, using epithelial cell adhesion molecule (EpCAM) as a model antigen, we used alanine scanning of the complementarity-determining region to fine-tune CAR affinity. This allowed us to identify CARs that could spare primary epithelial cells while still effectively targeting EpCAMhigh tumors. Although affinity-tuned CARs showed suboptimal antitumor activity in vivo, we found that inducible secretion of interleukin-12 (IL-12), under the control of the NFAT promoter, can restore CAR activity to levels close to that of the parental CAR. This strategy was further validated with another affinity-tuned CAR specific for intercellular adhesion molecule-1 (ICAM-1). Only in affinity-tuned CAR-T cells was NFAT activity stringently controlled and restricted to tumors expressing the antigen of interest at high levels. Our study demonstrates the feasibility of specifically gearing CAR-T cells towards recognition of solid tumors by combining inducible IL-12 expression and affinity-tuned CAR.
Insights
Researchers engineered chimeric antigen receptor (CAR)-T cells to target solid tumors by fine-tuning CAR affinity and inducing interleukin-12 (IL-12) secretion, enhancing tumor recognition and activity.
Area of Science:
- Immunology
- Oncology
- Biotechnology
Background:
- Solid tumors present challenges for chimeric antigen receptor (CAR)-T cell therapy due to limited tumor-specific antigens and immunosuppressive microenvironments.
- Developing CAR-T cells that effectively target cancer cells while sparing healthy tissues is crucial for therapeutic success.
Purpose of the Study:
- To engineer CAR-T cells with enhanced specificity and efficacy against solid tumors.
- To investigate the combined strategy of affinity-tuned CARs and inducible interleukin-12 (IL-12) secretion for improved solid tumor targeting.
Main Methods:
- Alanine scanning of the complementarity-determining region (CDR) was used to fine-tune CAR affinity for epithelial cell adhesion molecule (EpCAM) and intercellular adhesion molecule-1 (ICAM-1).
- Inducible secretion of IL-12, controlled by the NFAT promoter, was incorporated into affinity-tuned CAR-T cells.
- The activity and specificity of engineered CAR-T cells were evaluated in vitro and in vivo models.
Main Results:
- Affinity-tuned CARs demonstrated the ability to distinguish between EpCAM-high tumors and normal epithelial cells.
- While affinity-tuned CARs alone showed limited in vivo antitumor activity, inducible IL-12 secretion restored efficacy to near parental CAR levels.
- NFAT activity in engineered CAR-T cells was strictly controlled and tumor-restricted, particularly in affinity-tuned CAR-T cells.
Conclusions:
- Combining affinity-tuned CARs with inducible IL-12 secretion is a feasible strategy to enhance CAR-T cell targeting of solid tumors.
- This approach allows for specific recognition of tumor antigens and controlled immune activation, overcoming key barriers in solid tumor immunotherapy.
