Innovative Strategies of Reprogramming Immune System Cells by Targeting CRISPR/Cas9-Based Genome-Editing Tools: A New Era of Cancer Management

Abstract

The recent developments in the study of clustered regularly interspaced short palindromic repeats/associated protein 9 (CRISPR/Cas9) system have revolutionized the art of genome-editing and its applications for cellular differentiation and immune response behavior. This technology has further helped in understanding the mysteries of cancer progression and possible designing of novel antitumor immunotherapies. CRISPR/Cas9-based genome-editing is now often used to engineer universal T-cells, equipped with recombinant T-cell receptor (TCR) or chimeric antigen receptor (CAR). In addition, this technology is used in cytokine stimulation, antibody designing, natural killer (NK) cell transfer, and to overcome immune checkpoints. The innovative potential of CRISPR/Cas9 in preparing the building blocks of adoptive cell transfer (ACT) immunotherapy has opened a new window of antitumor immunotherapy and some of them have gained FDA approval. The manipulation of immunogenetic regulators has opened a new interface for designing, implementation and interpretation of CRISPR/Cas9-based screening in immuno-oncology. Several cancers like lymphoma, melanoma, lung, and liver malignancies have been treated with this strategy, once thought to be impossible. The safe and efficient delivery of CRISPR/Cas9 system within the immune cells for the genome-editing strategy is a challenging task which needs to be sorted out for efficient immunotherapy. Several targeting approaches like virus-mediated, electroporation, microinjection and nanoformulation-based methods have been used, but each procedure offers some limitations. Here, we elaborate the recent updates of cancer management through immunotherapy in partnership with CRISPR/Cas9 technology. Further, some innovative methods of targeting this genome-editing system within the immune system cells for reprogramming them, as a novel strategy of anticancer immunotherapy is elaborated. In addition, future prospects and clinical trials are also discussed.

Recent Updates of the CRISPR/Cas9 Genome Editing System: Novel Approaches to Regulate Its Spatiotemporal Control by Genetic and Physicochemical Strategies

“…In addition, spatiotemporal control by thermal/optical/magnetic/ultrasonic activation of the CRISPR/Cas9 system maximizes its application in different clinical applications. 20–22 However, all of these strategies are suboptimal and have some shortcomings ( Table 1 ). Therefore, the majority of CRISPR/Cas9 regulation strategies have only been tested in cell lines in vitro.…”

“…These variants included eSpCas9, evoCas9, HypaCas9, Sniper-Cas9, SpCas9-HF1, SpCas92Pro and xCas9 3.7. 20 , 110 , 111 These engineered Cas9 variants exhibited reduced off-target effects and/or potential cleavage activities to different degrees. Consequently, choosing the correct Cas9 variant is crucial, but difficult.…”

“… 19 The roles of cell-specific promoters, small-molecule activators/inhibitors, bioresponsive delivery approaches, and control by thermal/optical/magnetic/ultrasonic activation of the CRISPR/Cas9 system have been studied. 20–22 Each approach has its limitations and most of the strategies are used by in vitro cell lines; however, their programmable applications under in vivo conditions continue to struggle. Thus, a thorough knowledge of precise spatiotemporal control over CRISPR/Cas9 by using different methods is needed to utilize this genome-editing tool for innovative applications.…”

CRISPR technology in human diseases

“… 328 CRISPR/Cas9‐based genome editing offers clinical therapeutic potential for immunotherapies such as TCR, CAR T cells, and over‐the‐counter cell transfer (ACT). 329 CAR T‐cell therapies are primarily designed to target diseases individually, and one study used ABE base editing to install a function‐preserving mutation that protects CAR T cells and healthy hematopoietic cells from the toxic effects of CD45 targeting, to develop universal CAR T‐cell therapies targeting panleukopoietic CD45 markers for AML, B‐cell lymphoma and acute T‐cell leukemia. 330 Another study used CRISPR–Cas9 to generate gene‐specific targeted nonviral CAR‐T cells and inserted an anti‐CD19 CAR cassette into the AAVS1 safety motif to develop innovative anti‐CD19 CAR‐T cells integrated with PD1.…”