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BackgroundChimeric antigen receptor (CAR) T cells have demonstrated high clinical response rates against hematological malignancies (e.g., CD19+ cancers) but have shown limited activity in patients with solid tumors. Recent work showed that precise insertion of a CAR at a defined locus improves treatment outcomes in the context of a CD19 CAR; however, it is unclear if such a strategy could also affect outcomes in solid tumors. Furthermore, CAR manufacturing generally relies on viral vectors for gene delivery, which comprise a complex and resource-intensive part of the manufacturing supply chain.MethodsAnti-GD2 CAR T cells were generated using CRISPR/Cas9 within 9 days using recombinant Cas9 protein and nucleic acids, without any viral vectors. The CAR was specifically targeted to the T cell receptor alpha constant gene (TRAC). T cell products were characterized at the level of the genome, transcriptome, proteome, and secretome using CHANGE-seq, targeted next-generation sequencing, scRNA-seq, spectral cytometry, and ELISA assays, respectively. Functionality was evaluated in vivo in an NSG™ xenograft neuroblastoma model.ResultsIn comparison to retroviral CAR T cells, virus-free CRISPR CAR (VFC-CAR) T cells exhibit TRAC-targeted genomic integration of the CAR transgene, elevation of transcriptional and protein characteristics associated with a memory-like phenotype, and low tonic signaling prior to infusion arising in part from the knockout of the T cell receptor. On exposure to the GD2 target antigen, anti-GD2 VFC-CAR T cells exhibit specific cytotoxicity against GD2+ cells in vitro and induce solid tumor regression in vivo. VFC-CAR T cells demonstrate robust homing and persistence and decreased exhaustion relative to retroviral CAR T cells against a human neuroblastoma xenograft model.ConclusionsThis study leverages virus-free genome editing technology to generate CAR T cells featuring a TRAC-targeted CAR, which could inform manufacturing of CAR T cells to treat cancers, including solid tumors.

Natural killer (NK) cells play a crucial role in host immunity by detecting cells that downregulate MHC class I presentation and upregulate stress ligands, as commonly seen in cancers. Current NK therapies using primary NK cells are prone to manufacturing issues related to expansion and storage. Alternative cell sources utilizing immortalized NK cell lines require irradiation and are dependent on systemic IL-2 administration, which has been associated with adverse effects. In contrast, NK cells differentiated from induced pluripotent stem cells (iPSC-NK cells) offer an off-the-shelf alternative that may overcome these bottlenecks. The development of a serum-free and feeder-free differentiation protocol allows for the manufacturing of clinically adaptable iPSC-NK cells that are equally as effective as primary NK cells and the NK-92 cell line for many indications. Moreover, genetic modifications targeting NK-mediated antibody-dependent cellular cytotoxicity capabilities, cytotoxicity, and checkpoint inhibitors may increase the therapeutic potential of iPSC-NK products. This review will highlight the current sources for NK therapies and their respective constraints, discuss recent developments in the manufacturing and genetic engineering of iPSC-NK cells, and provide an overview of ongoing clinical trials using NK cells.

Chronic respiratory disease affects many people worldwide with little known about the intricate mechanisms driving the pathology, making it difficult to develop novel therapies. Improving the understanding of airway smooth muscle and extracellular matrix (ECM) interactions is key to developing treatments for this leading cause of death. With currently no relevant or controllable in vivo or in vitro models to investigate cell–ECM interactions in the small airways, the development of a biomimetic in vitro model with cell attachment, signaling, and organization is needed. The goal of this study was to create a biologically and structurally relevant in vitro model of small airway smooth muscle. In order to achieve this goal, a scaffold was engineered from synthetic poly-l-lactic acid (PLLA) and decellularized pig lung ECM (PLECM). PLECM scaffolds have improved physical characteristics over synthetic scaffolds, by exhibiting a significant decrease in the elastic modulus and an increase in hydrophilicity. Histological staining and SDS-PAGE showed that essential proteins or protein fragments found in natural ECM were present after processing. Human bronchial smooth muscle cells (HBSMCs) seeded onto PLECM 3D scaffolds formed confluent layers and maintained a contractile phenotype, as demonstrated by the organized arrangement of actin filaments within the cell and expected contractile protein expression of calponin 1. HBSMCs cultured on electrospun PLECM scaffold also increased alpha-1 type 1 collagen compared to those cultured on PLLA scaffolds. In summary, this research demonstrates that a PLLA/PLECM composite electrospun mat is a promising tool to produce an in vitro model of the airway with the potential for a better understanding of bronchiole smooth muscle behavior in diseased or normal states.