Immunological quality and performance of tumor vessel-targeting CAR-T cells prepared by mRNA-EP for clinical research.

Inoo K1, Inagaki R1, Fujiwara K1, Sasawatari S2, Kamigaki T3, Nakagawa S1, Okada N1.

Mol Ther Oncolytics. 2016 Nov 16;3:16024. eCollection 2016.

Abstract

We previously reported that tumor vessel-redirected T cells, which were genetically engineered with chimeric antigen receptor (CAR) specific for vascular endothelial growth factor receptor 2 (VEGFR2), demonstrated significant antitumor effects in various murine solid tumor models. In the present study, we prepared anti-VEGFR2 CAR-Tcells by CAR-coding mRNA electroporation (mRNA-EP) and analyzed their immunological characteristics and functions for use in clinicalresearch. The expression of anti-VEGFR2 CAR on murine and human T cells was detected with approximately 100% efficiency for a few days, after peaking 6-12 hours after mRNA-EP. Triple transfer of murine anti-VEGFR2 CAR-Tcells into B16BL6 tumor-bearing mice demonstrated an antitumor effect comparable to that for the single transfer of CAR-Tcells engineered with retroviral vector. The mRNA-EP did not cause any damage or defects to human T-cell characteristics, as determined by viability, growth, and phenotypic parameters. Additionally, two kinds of human anti-VEGFR2 CAR-Tcells, which expressed different CAR construction, differentiated to effector phase with cytokine secretion and cytotoxic activity in antigen-specific manner. These results indicate that our anti-VEGFR2 CAR-Tcellsprepared by mRNA-EP have the potential in terms of quality and performance to offer the prospect of safety and efficacy in clinicalresearch as cellular medicine.