Targeted delivery can improve drug accumulation in tumor tissue and treatment outcomes. However, currently available options suffer from a lack of selectivity for tumor cells. Mesenchymal Stem cells (MSCs) can be engineered with chemotherapeutic-loaded polymeric nanoparticles (PNPs) for tumor-targeted delivery, owing to their characteristic tumor tropic properties. Although nano-engineered MSCs demonstrated significant anticancer activity in multiple ovarian cancer models, their non-specific accumulation in clearance organs such as lungs and liver remains a concern. Parallel to the concept of chimeric antigen receptor (CAR)-T cell therapy, we advance here a strategy of modifying MSCs with synthetic antigen receptors (SARs) that target specific antigens overexpressed on cancer cells. Our approach consists of stably incorporating recombinant protein G (PG) on the surface of MSCs, followed by binding of a full-length IgG to the PG handle. Because protein G binds to the Fc region of IgG, antigen-binding affinity of the antibody is conserved. Epidermal growth factor receptor (EGFR) has been reported to be overexpressed and implicated in the pathogenesis of several malignancies especially lung cancer. Cetuximab (Cmab) is an anti-EGFR monoclonal antibody used in the treatment of metastatic lung cancer. In the current study, SAR-MSCs were developed by coating the nano-engineered MSCs with palmitated PG, followed by incorporating Cmab on the cell surface. Flow cytometry and confocal microscopy were used to confirm the incorporation of fluorescently labeled PAPG handle on MSC surface. Similarly, the installation of fluorescently labeled antibody on PAPG-functionalized MSCs was confirmed by flow cytometry. Preliminary efficacy studies in a mouse orthotopic A549-luc human lung adenocarcinoma model demonstrated significantly (P<0.05) improved survival of mice treated with Cmab-modified nano-engineered MSCs compared to isotype IgG-modified nano-engineered MSCs control group. These results suggest that the SAR technology could further improve the effectiveness of MSCs as tumor targeted drug delivery vehicles.

Citation Format: Susheel Kumar Nethi, Drishti Sehgal, Jayanth Panyam, Swayam Prabha. Augmented lung tumor infiltration of chemotherapeutics using synthetic antigen receptor- mesenchymal stem cells (SAR-MSCs) [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 6255.