Human iPSC-Derived Natural Killer Cells Engineered with Chimeric Antigen Receptors Enhance Anti-tumor Activity

Abstract

Chimeric antigen receptors (CARs) significantly enhance the anti-tumor activity of immune effector cells. Although most studies have evaluated CAR expression in T cells, here we evaluate different CAR constructs that improve natural killer (NK) cell-mediated killing. We identified a CAR containing the transmembrane domain of NKG2D, the 2B4 co-stimulatory domain, and the CD3ζ signaling domain to mediate strong antigen-specific NK cell signaling. NK cells derived from human iPSCs that express this CAR (NK-CAR-iPSC-NK cells) have a typical NK cell phenotype and demonstrate improved anti-tumor activity compared with T-CAR-expressing iPSC-derived NK cells (T-CAR-iPSC-NK cells) and non-CAR-expressing cells. In an ovarian cancer xenograft model, NK-CAR-iPSC-NK cells significantly inhibited tumor growth and prolonged survival compared with PB-NK cells, iPSC-NK cells, or T-CAR-iPSC-NK cells. Additionally, NK-CAR-iPSC-NK cells demonstrate in vivo activity similar to that of T-CAR-expressing T cells, although with less toxicity. These NK-CAR-iPSC-NK cells now provide standardized, targeted "off-the-shelf" lymphocytes for anti-cancer immunotherapy.

Expression of a recombinant high affinity IgG Fc receptor by engineered NK cells as a docking platform for therapeutic mAbs to target cancer cells

“…Genetically modifying peripheral blood NK cells by retroviral or lentiviral transduction at this point has been challenging (36). Embryonic stem cells and iPSCs can be differentiated into cytolytic NK cells in vitro (28–31, 37), and these cells are highly amendable to genetic engineering (14, 30, 38, 39). Undifferentiated iPSCs were transduced to express CD64/16A using a sleeping beauty transposon plasmid for nonrandom gene insertion and stable expression.…”

Induced Pluripotent Stem Cell-derived CAR-Macrophage Cells with Antigen-dependent Anti-Cancer Cell Functions for Liquid and Solid Tumors

“…Recently, iPSC-differentiated CAR-expressing T cells and NK cells have been reported to have potent cytotoxic activity against cancer cells, and they represent a new family of engineered stem cell-derived immune cells for CAR therapies 5,6 A new member of this family, CAR-iMac has three advantages. First, CAR-iMac can be utilized to specifically "eat" tumor cells or to alter the tumor microenvironment, especially when its function is antigen-dependent, providing a tool to directly kill tumor cells or to modulate a specific niche at the interface of tumor and immune cells.…”

“…However, there are a few outstanding challenges for engineering primary immune cells, including variable transduction efficiency, highly heterogeneous genetic outcomes upon editing the genome of the targeted cells, and limited cell resources for certain cases such as from hematological cancer patients for which immune cell itself is transformed. iPSC-derived immune cells, due to their flexibility of expansion and genome editing at the iPSC stage 3,4 , in theory have advantages in 3 dealing with those challenges above, and have been proved to be effective in treating B cell and ovarian cancer cells in pre-clinical settings such as iPSC differentiated T cells 5 and NK cells 6 .…”

Enhancing network activation in Natural Killer cells: Predictions from in silico modeling

“…These predictions are relevant for developing immunotherapeutic strategies. Researchers in recent years have designed CARs for NK cells that include intracellular signaling domains of CD16, 2B4 and NKG2D for anti-tumor therapy (47,48). Those studies found that CARs comprised of CD16, 2B4 and NKG2D signaling domains together outperformed activation induced by the individual receptors.…”