CAR-NK Cells from Engineered Pluripotent Stem Cells: Off-the-shelf Therapeutics for all Patients

Abstract

Clinical success of adoptive cell therapy with chimeric antigen receptor (CAR) T cells for treating hematological malignancies has revolutionized the field of cellular immunotherapy. However, due to the nature of utilizing autologous T cells, affordability and availability are major hurdles, in addition to scientific challenges relating to CAR-T therapy optimization. Natural killer (NK) cell is a specialized immune effector cell type that recognizes and kills targets without human leukocyte antigen (HLA) restriction and prior sensitization. CAR-NK cells do not cause graft vs host disease and can be obtained from unrelated donors as well as pluripotent stem cells (PSC), representing an ideal off-the-shelf therapeutics readily available for patients. Furthermore, unlike cytotoxic T cells, NK cells specifically target and eliminate cancer stem cells, which are the cells causing relapse and metastasis. PSCs can be genetically manipulated and engineered with CARs at the pluripotent stage, which allows the establishment of permanent, stable, and clonal PSC-CAR lines for the manufacture of unlimited homogenous CAR-NK cells. Multiple master PSC-CAR cell banks targeting a variety of antigens for cancer, viral infection, and autoimmune diseases provide inexhaustible cell sources for all patients. Development of a next-generation 3D bioreactor platform for PSC expansion and NK cell production overcomes major barriers related to cost and scalability for CAR-NK product.

CAR-NK cells for cancer immunotherapy: from bench to bedside

“…On the one hand, CAR-NK cells can be conveniently prepared from a wider range of autogenous and allogeneic sources without causing severe adverse reaction (e.g., aGVHD, CRS) by CAR-T-based implantation. On the other hand, CAR-NK cells are adequate for cell immunosurveillance dispense with pre-sensitization and thus have more flexible killing capacity upon both hematologic and solid tumor cells over CAR-T cells via both the CAR-dependent manner and CAR-independent intrinsic mechanisms, which thus provide alternative strategies for conquering tumor escape and varied adverse events (e.g., “on-target, off-tumor toxicity” during CAR-T application) [ 5 , 112 , 117 , 147 ].…”

A Hot Topic: Cancer Immunotherapy and Natural Killer Cells

“…It was frequently objected that NK cells are never antigen-specific, an argument that is no longer valid with the arrival of CAR-NK cells in preclinical studies and clinical trials. Adult iPSC allow to obtain high numbers of NK cells, are easily accessible (theoretically, any somatic cell type might be reprogrammable into iPSC) because mostly skin fibroblasts or PBMC are used [ 74 , 75 ], and avoid the ethically highly debatable approach with embryonic stem cells. Once suitable homogeneous iPSC clones are selected, they can be banked and are further expandable and differentiable into the desired end product.…”

“…Once suitable homogeneous iPSC clones are selected, they can be banked and are further expandable and differentiable into the desired end product. Several methods and protocols to end up with NK cells have been published, although they are not yet entirely problem-free [ 74 , 75 ].…”

Cell Culture Process Scale-Up Challenges for Commercial-Scale Manufacturing of Allogeneic Pluripotent Stem Cell Products

“…Examples of cell types that can be cultured as aggregates include PSCs, neural stem cells [11], and mammary epithelial stem cells [12]. In contrast, hematopoietic stem/progenitor cells and immune cells like T cells and NK cells are typically grown as single cells or loose clumps [13].…”