Novelty in improvement of CAR T cell-based immunotherapy with the aid of CRISPR system

Abstract

Introduction: Chimeric Antigen Receptor (CAR) T cells have tremendous potentials for cancer treatment; however, various challenges impede their universal use. These restrictions include the poor function of T cells in tumor microenvironments, the shortage of tumor-specific antigens and, finally, the high cost and time-consuming process, as well as the poor scalability of the method. Creative gene-editing tools have addressed each of these limitations and introduced next generation products for cell therapy. The clustered regularly interspaced short palindromic repeats-associated endonuclease 9 (CRISPR/Cas9) system has triggered a revolution in biology fields, as it has a great capacity for genetic manipulation.

Method: In this review, we considered the latest development of CRISPR/Cas9 methods for the chimeric antigen receptor T cell (CAR T)-based immunotherapy.

Results: The ability of the CRISPR/Cas9 system to generate the universal CAR T cells and also potent T cells that are persistent against exhaustion and inhibition was explored.

Conclusion: We explained CRISPR delivery methods, as well as addressing safety concerns related to the use of the CRISPR/Cas9 system and their potential solutions.

Keywords: Adoptive immunotherapy; CRISPR/Cas9; Cancer treatment; Chimeric antigen receptor; Gene therapy.

Figure 1

The basic structure of the CAR. CARs consist of three segments: 1) an extracellular binding element; 2) a transmembrane portion (TM), and; 3) the intracellular signaling domain. Commonly, the binding portion consists of an scFv domain taken from a TAA-specific monoclonal antibody and a signaling domain or domains derived from the TCR activating and co-stimulatory elements.

Figure 2

The four generations of the chimeric antigen of CAR-T cell receptor and common targets on tumor cells. Various CAR-T cell generations are shown with various intracellular segments.

Figure 3

Improvement of CAR-T cell therapy by CRISPR/Cas9 technology: three major aspects of the CRISPR/Cas9 application in the CAR-T cell therapy: 1) the production of the universal CAR-T cell via disturbing endogenous MHC and TCR molecules to destroy GvH and HvG; 2) CAR-T augmentation by broadening the range of untargetable CAR antigen, and; 3) knock-out checkpoint inhibitors for improving antitumor ability.