Adoptive NK cell therapies in children with cancer: Clinical challenges and future possibilities

2021 ◽  
pp. 405-437
Author(s):  
Rosa Nguyen ◽  
Wayne L. Furman
Keyword(s):  
Nk Cell ◽  
Children With Cancer ◽  
Cell Therapies

scholarly journals Approaches to Enhance Natural Killer Cell-Based Immunotherapy for Pediatric Solid Tumors

Cancers ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 2796
Author(s):  
Aicha E. Quamine ◽  
Mallery R. Olsen ◽  
Monica M. Cho ◽  
Christian M. Capitini
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
Solid Tumors ◽  
Nk Cell ◽  
Therapeutic Option ◽  
Treatment Options ◽  
Intensive Therapy ◽  
Killer Cell ◽  
Cell Therapies ◽  
Pediatric Solid Tumors

Treatment of metastatic pediatric solid tumors remain a significant challenge, particularly in relapsed and refractory settings. Standard treatment has included surgical resection, radiation, chemotherapy, and, in the case of neuroblastoma, immunotherapy. Despite such intensive therapy, cancer recurrence is common, and most tumors become refractory to prior therapy, leaving patients with few conventional treatment options. Natural killer (NK) cells are non-major histocompatibility complex (MHC)-restricted lymphocytes that boast several complex killing mechanisms but at an added advantage of not causing graft-versus-host disease, making use of allogeneic NK cells a potential therapeutic option. On top of their killing capacity, NK cells also produce several cytokines and growth factors that act as key regulators of the adaptive immune system, positioning themselves as ideal effector cells for stimulating heavily pretreated immune systems. Despite this promise, clinical efficacy of adoptive NK cell therapy to date has been inconsistent, prompting a detailed understanding of the biological pathways within NK cells that can be leveraged to develop “next generation” NK cell therapies. Here, we review advances in current approaches to optimizing the NK cell antitumor response including combination with other immunotherapies, cytokines, checkpoint inhibition, and engineering NK cells with chimeric antigen receptors (CARs) for the treatment of pediatric solid tumors.

Regulating Innovation in the Early Development of Cell Therapies

2020 ◽  
Author(s):  
Andrew R Exley ◽  
James McBlane
Keyword(s):  
Clinical Trials ◽  
Nk Cell ◽  
Genetic Manipulation ◽  
Clinical Trial Data ◽  
Cell Receptor ◽  
Mitigation Measures ◽  
Safety Testing ◽  
Cell Therapies ◽  
Commercial Use ◽  
Allogeneic Cell

Abstract Clinical need for paradigm shifts in efficacy and safety is driving the rapid and wide-ranging innovation in cell therapies for cancer beyond existing regulatory frameworks. Critical issues emerging during clinical trials frequently reflect unresolved elements of the regulation of innovation conundrum from earlier stages of development. We address this challenge using a global regulators’ perspective on the pre-clinical development of cell therapies, as a navigational aid to intended commercial use which maximises the clinical relevance of developmental data. We examine the implications of tumour targeting based on B cell, NK cell, conventional and unconventional T cell receptor domains; multiplex approaches; genetic manipulation strategies; and autologous versus allogeneic cell sources. We propose that detailed characterisation of both the cell source and final product is critical to optimising manufacture of individualised autologous or off the shelf allogeneic cell therapies, enabling product consistency to underpin extrapolation of clinical trial data to the expected commercial use. We highlight preclinical approaches to characterising target antigens including the Human Cell Atlas initiative, multi-dimensional cell culture, and safety testing against activated, proliferating or stressed control cells. Practical solutions are provided for preclinical toxicity studies when cell therapies target uniquely human tumour antigens, including illustrative mitigation measures for potential toxicity likely to support timely approval of first in human clinical trials. We recommend addressing the regulation of innovation conundrum through serial engagement between innovators and regulators early in the development of cell therapies for cancer, accelerating patient access whilst safeguarding against unacceptable toxicities.

scholarly journals Horses for Courses in the Era of CARs: Advancing CAR T and CAR NK Cell Therapies

2021 ◽  
Vol 11 (11) ◽  
pp. 1182
Author(s):  
Sergey Kulemzin ◽  
Igor Evsyukov ◽  
Tatiana Belovezhets ◽  
Alexander Taranin ◽  
Andrey Gorchakov
Keyword(s):  
Nk Cells ◽  
Nk Cell ◽  
Great Promise ◽  
B Cell Malignancies ◽  
T Cell Therapy ◽  
Cell Therapies ◽  
Biological Features ◽  
Car T Cell Therapy ◽  
Car T ◽  
Antitumor Properties

The adoptive transfer of allogeneic CAR NK cells holds great promise as an anticancer modality due to the relative ease of manufacturing and genetic modification of NK cells, which translates into affordable pricing. Compared to the pronounced efficacy of CAR T cell therapy in the treatment of B cell malignancies, rigorous clinical and preclinical assessment of the antitumor properties of CAR NK cells has been lagging behind. In this brief review, we summarize the biological features of NK cells that may help define the therapeutic niche of CAR NK cells as well as create more potent NK cell-based anticancer products. In addition, we compare T cells and NK cells as the carriers of CARs using the data of single-cell transcriptomic analysis.

scholarly journals Importance of T, NK, CAR T and CAR NK Cell Metabolic Fitness for Effective Anti-Cancer Therapy: A Continuous Learning Process Allowing the Optimization of T, NK and CAR-Based Anti-Cancer Therapies

Cancers ◽  
2021 ◽  
Vol 14 (1) ◽  
pp. 183
Author(s):  
Adrien Krug ◽  
Adriana Martinez-Turtos ◽  
Els Verhoeyen
Keyword(s):  
Nk Cells ◽  
Nk Cell ◽  
Building Blocks ◽  
Cancer Therapies ◽  
Cell Therapies ◽  
Anti Cancer ◽  
Car T ◽  
Metabolic Fitness

Chimeric antigen receptor (CAR) T and CAR NK cell therapies opened new avenues for cancer treatment. Although original successes of CAR T and CAR NK cells for the treatment of hematological malignancies were extraordinary, several obstacles have since been revealed, in particular their use for the treatment of solid cancers. The tumor microenvironment (TME) is competing for nutrients with T and NK cells and their CAR-expressing counterparts, paralyzing their metabolic effective and active states. Consequently, this can lead to alterations in their anti-tumoral capacity and persistence in vivo. High glucose uptake and the depletion of key amino acids by the TME can deprive T and NK cells of energy and building blocks, which turns them into a state of anergy, where they are unable to exert cytotoxic activity against cancer cells. This is especially true in the context of an immune-suppressive TME. In order to re-invigorate the T, NK, CAR T and CAR NK cell-mediated antitumor response, the field is now attempting to understand how metabolic pathways might change T and NK responses and functions, as well as those from their CAR-expressing partners. This revealed ways to metabolically rewire these cells by using metabolic enhancers or optimizing pre-infusion in vitro cultures of these cells. Importantly, next-generation CAR T and CAR NK products might include in the future the necessary metabolic requirements by improving their design, manufacturing process and other parameters. This will allow the overcoming of current limitations due to their interaction with the suppressive TME. In a clinical setting, this might improve their anti-cancer effector activity in synergy with immunotherapies. In this review, we discuss how the tumor cells and TME interfere with T and NK cell metabolic requirements. This may potentially lead to therapeutic approaches that enhance the metabolic fitness of CAR T and CAR NK cells, with the objective to improve their anti-cancer capacity.

scholarly journals A Phase I Study of FT538, a First-of-Kind, Off-the-Shelf, Multiplexed Engineered, iPSC-Derived NK Cell Therapy As Monotherapy in Relapsed/Refractory Acute Myelogenous Leukemia and in Combination with Daratumumab or Elotuzumab in Relapsed/Refractory Multiple Myeloma

Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 3-3
Author(s):  
Murali Janakiram ◽  
Ravi Vij ◽  
David S. Siegel ◽  
Ted Shih ◽  
Sara Weymer ◽  
...  
Keyword(s):  
Nk Cells ◽  
Research Funding ◽  
Nk Cell ◽  
Myelogenous Leukemia ◽  
Publicly Traded ◽  
Advisory Committees ◽  
Cell Therapies ◽  
Acute Myelogenous

Background: Allogeneic natural killer (NK) cell therapies have been well-tolerated with documented anti-tumor activity in patients with relapsed/refractory (r/r) hematologic malignancies including acute myelogenous leukemia (AML) and multiple myeloma (MM) (Lupo et al. 2019). Allogeneic NK cell therapies may offer an improved safety profile characterized by the absence of cytokine release syndrome and neurologic toxicity compared with T-cell therapies (Liu et al. 2020). However, in comparison to T cells, NK cells have limited in vivo expansion and a short half-life, and the potential to generate deeper and more durable anti-tumor responses through multi-dose administration is limited by the inability to consistently manufacture and administer more than one dose of allogeneic NK cells. The monoclonal antibodies (mAbs) daratumumab and elotuzumab have demonstrated clinical benefit and are approved for the treatment of MM (Darzalex® USPI, Empliciti® USPI). However, durable responses and disease-free survival remain limited. Engagement of the Fc portion of the mAb with CD16 on NK cells, which promotes antibody-dependent cellular cytotoxicity (ADCC), is a major contributor to the efficacy of daratumumab and elotuzumab. It is hypothesized that more clinically meaningful outcomes may be achieved by combining therapeutic mAbs with allogeneic NK cells engineered to enhance ADCC. FT538 is an investigational, first-of-kind, multiplexed engineered NK cell therapy generated from a clonal master engineered induced pluripotent stem cell (iPSC) line, which can be used as a renewable source for the mass production of off-the-shelf NK cells for broad patient access. FT538 is engineered with three modalities for enhanced innate immunity: (1) high-affinity 158V, non-cleavable CD16 Fc receptor for augmented ADCC; (2) interleukin (IL)-15/IL-15 receptor fusion that promotes cytokine-autonomous persistence; and (3) CD38 knockout to mitigate NK cell fratricide by CD38-directed mAbs. In preclinical studies, FT538 combined with daratumumab against MM targets demonstrated avoidance of daratumumab-mediated fratricide and significantly enhanced ADCC in vitro in a serial stimulation cytotoxicity assay compared with peripheral blood NK cells, and the combination of FT538 with daratumumab led to highly effective tumor control compared with daratumumab alone in an in vivo MM xenograft model (Bjordahl et al. 2019). Study Design and Methods: This study is a multicenter, multi-dose, Phase I clinical trial of FT538 in patients with r/r AML or r/r MM. The primary objectives are to determine the recommended Phase II dose of FT538 as monotherapy in r/r AML and in combination with daratumumab or elotuzumab in r/r MM. Key secondary objectives include evaluation of FT538 safety and tolerability, anti-tumor activity, and pharmacokinetics (PK) as monotherapy in r/r AML and combined with mAbs in r/r MM. Exploratory objectives include characterization of FT538 pharmacodynamics as assessed by peripheral blood biomarkers, assessment of minimal residual disease, and characterization of the tumor microenvironment in pre- and post-treatment tumor biopsies. The dose-escalation part of the trial utilizes a 3+3 design to identify the maximum tolerated dose of up to three doses of FT538 on Days 1, 8, and 15 as a monotherapy in r/r AML (Regimen A) and in combination with daratumumab (Regimen B) or elotuzumab (Regimen C) in r/r MM. The dose-expansion part of the trial will further characterize the safety, efficacy, and PK of FT538 in all regimens. The trial will test up to five FT538 dose levels ranging from 50 million to 1.5 billion cells. Up to 105 patients will be enrolled. The mAbs in Regimens B and C will be administered based on dosing schedules per their respective prescribing information. Lympho-conditioning consisting of three consecutive days of fludarabine and cyclophosphamide will be administered prior to the first dose of FT538. Key inclusion criteria include r/r disease after standard approved therapies for r/r AML or r/r MM, as applicable, measurable disease for r/r MM, and adequate organ function. Key exclusion criteria include active central nervous system disease, need for systemic immunosuppressive therapy, and prior allograft organ transplant. This trial is expected to begin patient enrollment in 2020. Disclosures Janakiram: Takeda, Fate, Nektar: Research Funding. Siegel:Karyopharma: Consultancy, Honoraria; Takeda: Consultancy, Honoraria, Speakers Bureau; Merck: Consultancy, Honoraria, Speakers Bureau; Celulatiry: Consultancy; BMS: Consultancy, Honoraria, Speakers Bureau; Janssen: Consultancy, Honoraria, Speakers Bureau; Amgen: Consultancy, Honoraria, Speakers Bureau. Shih:Fate Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Weymer:Fate Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Valamehr:Fate Therapeutics, Inc: Current Employment, Current equity holder in publicly-traded company. Chu:Roche Holding AG: Current equity holder in publicly-traded company; Fate Therapeutics, Inc.: Current Employment, Current equity holder in publicly-traded company. Miller:Fate Therapeutics, Inc: Consultancy, Patents & Royalties, Research Funding; GT Biopharma: Consultancy, Patents & Royalties, Research Funding; Vycellix: Consultancy; Onkimmune: Honoraria, Membership on an entity's Board of Directors or advisory committees; Nektar: Honoraria, Membership on an entity's Board of Directors or advisory committees. OffLabel Disclosure: Cyclophosphamide and fludarabine will be used as lympho-conditioning therapy prior to FT538 administration.

AFM26 is a novel, highly potent BCMA/CD16A-directed bispecific antibody for high affinity NK-cell engagement in multiple myeloma.

2017 ◽  
Vol 35 (15_suppl) ◽  
pp. 8045-8045 ◽  
Author(s):  
Thorsten Gantke ◽  
Uwe Reusch ◽  
Christian Kellner ◽  
Kristina Ellwanger ◽  
Ivica Fucek ◽  
...  
Keyword(s):  
Multiple Myeloma ◽  
Nk Cells ◽  
Bispecific Antibody ◽  
Nk Cell ◽  
Cell Activity ◽  
Proteasome Inhibitors ◽  
Current Standard ◽  
Cell Therapies ◽  
Number Of Patients

8045 Background: Despite recent advances in the treatment of multiple myeloma (MM), novel therapies are needed to achieve long-lasting remissions in a greater number of patients. Natural killer (NK) cells play a key role in the immune response to MM and have been implicated in the clinical efficacy of current standard of care interventions, including IMiDs, proteasome inhibitors, recently approved immunotherapies and autologous stem cell transplantation (ASCT). Numerous strategies are being developed to enhance the natural NK-cell cytotoxicity against myeloma cells, which is frequently dysregulated in MM. Approaches include modulation of activity, through cytokine stimulation or immune checkpoint targeting, and adoptive transfer of culture expanded NK-cells in ASCT-eligible MM. While highly attractive, these approaches are non-targeted, as they rely on the natural cytotoxicity of NK-cells, and may benefit from antigen-specific retargeting and effector activation. AFM26 is a novel tetravalent, bispecific antibody designed to specifically enhance NK-cell anti-MM activity by redirecting NK-cell lysis to BCMA, an antigen expressed on MM cells. Methods: NK-cell engagement and cytotoxicity of AFM26 towards MM cell lines and freshly isolated tumor cells from MM patients was characterized in vitro and compared with classical antibody formats. Results: AFM26 engages NK-cells with superior avidity ( KD: 1-2nM) through bivalent interaction with CD16A (FcγRIIIa) and demonstrates extended cell surface retention that is not affected by high level IgG, as is particularly relevant in MM. Importantly, AFM26 does not induce NK-cell depletion but selectively induces potent and efficacious lysis of MM cells in vitro. Conclusions: In summary, AFM26 is a promising candidate to enhance NK-cell activity and confer tumor-specificity to NK-cells in MM. Differentiation of AFM26 from classical antibody formats and its potential for combination with cellular NK-cell therapies is highlighted.

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

2018 ◽  
Author(s):  
Sahak Z. Makaryan ◽  
Stacey D. Finley
Keyword(s):  
Nk Cells ◽  
Natural Killer ◽  
In Silico ◽  
Intracellular Signaling ◽  
Cell Activation ◽  
Nk Cell ◽  
Mechanistic Model ◽  
Published Data ◽  
Cell Therapies ◽  
Network Activation

ABSTRACTNatural killer (NK) cells are part of the innate immune system and are capable of killing diseased cells. As a result, NK cells are being used for adoptive cell therapies for cancer patients. The activation of NK cell stimulatory receptors leads to a cascade of intracellular phosphorylation reactions, which activates key signaling species that facilitate the secretion of cytolytic molecules required for cell killing. Strategies that maximize the activation of such intracellular species can increase the likelihood of NK cell activation upon contact with a cancer cell, and thereby improve efficacy of NK cell-based therapies. However, due to the complexity of intracellular signaling, it is difficult to deduce a priori which strategies can enhance species activation. Therefore, we constructed a mechanistic model of the CD16, 2B4 and NKG2D signaling pathways in NK cells to simulate strategies that enhance signaling. The model predictions were fit to published data and validated with a separate dataset. Model simulations demonstrate strong network activation when the CD16 pathway is stimulated. The magnitude of species activation is most sensitive to the receptor concentration and the rate at which the receptor is deactivated. Co-stimulation of CD16 and NKG2D in silico required fewer ligands to achieve half-maximal activation than other combinations, suggesting co-stimulating these pathways is most effective in activating the species. We applied the model to predict the effects of perturbing the signaling network and found two strategies that can potently enhance network activation. When the availability of ligands is low, it is more influential to engineer NK cell receptors that are resistant to proteolytic cleavage. In contrast, for high ligand concentrations, inhibiting phosphatase activity leads to more activation. The work presented here establishes a framework for understanding the complex, nonlinear aspects of NK cell signaling and provides detailed strategies for enhancing NK cell activation.

scholarly journals Off-the-Shelf, iPSC-Derived CAR-NK Cells Multiplexed-Engineered for the Avoidance of Allogeneic Host Immune Cell Rejection

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 2795-2795
Author(s):  
Rina M Mbofung ◽  
Alan M Williams ◽  
Ken Hayama ◽  
Yijia Pan ◽  
Brian Groff ◽  
...  
Keyword(s):  
Immune System ◽  
T Cell ◽  
Nk Cells ◽  
T Cell Activation ◽  
Cell Activation ◽  
Immune Cell ◽  
Nk Cell ◽  
Cell Reactivity ◽  
Cell Therapies ◽  
Cell Numbers

Abstract Allogeneic off-the-shelf cell therapies offer distinct advantages over conventional autologous cell therapies in terms of scaled manufacturing, on-demand availability and optimization of cellular starting material. A unique consideration in the use of allogeneic cell therapies is the potential for immune cell-mediated recognition of the allogeneic cell product by the patient's immune system. CAR T-cell therapies are commonly combined with conditioning chemotherapies that suppress a patient's immune system, creating a suitable window of activity to elicit clinical response. However, protracted lympho-conditioning also affects immune reconstitution and can negatively impact the rate of infection. Alternative approaches to prevent allorejection may therefore help to enhance the efficacy of the therapy while preserving the immune system of the patient. Elimination of cell-surface human leukocyte antigen (HLA) molecule expression by genetic knockout (KO) has long been known to abrogate T-cell reactivity. However, loss of class I HLA elicits NK cell-mediated recognition and clearance, and therefore must be combined with other immune-modulating strategies to limit host NK cell reactivity. Allogeneic models combining class I HLA deletion with NK cell inhibitory molecules, such as HLA-E and CD47, have been shown to abrogate NK cell reactivity in mouse models. However, HLA-E is the canonical activator of NKG2C, a dominant activating receptor found on human NK cells. Likewise, the expression of signal regulatory protein alpha (SIRPα), the major interactor for CD47, is mostly restricted to macrophages and dendritic cells and not human NK cells, and the observed effects of this immune-modulating strategy in the mouse system may only offer partial or incomplete immune evasion in the human system. In this study, we provide details of a bona fide off-the-shelf strategy where iPSC-derived NK (iNK) cell therapy is multiplexed engineered with a novel combination of immune-evasion modalities; beta 2 microgobulin (B2M) KO to prevent CD8 T-cell mediated rejection; class II transactivator (CIITA) KO to prevent CD4 T-cell mediated rejection; and CD38 KO to enable combination with anti-CD38 mAbs, which can be administered to deplete host alloreactive lymphocytes, including both NK and T cells. In vitro mixed lymphocyte reaction (MLR) data demonstrated that upon co-culture with allogeneic PBMCs, B2M KO iNK cells stimulated less T-cell activation than their B2M sufficient counterparts as evidenced by reduced CD38, 41BB, and CD25 levels on T cells. Additionally, B2M KO iNK cells impaired T-cell expansion over the duration of co-culture, resulting in a 50% decrease in expansion at the peak of the control response. However, B2M KO iNK cells were depleted over time, suggesting activation of an NK cell "missing self" response by the peripheral blood NK (pbNK) cells. In contrast, when the assay was performed in the presence of anti-CD38 mAb, depletion of B2M KO iNK cells was blocked, and instead B2M KO iNK cell numbers increased by 3.5-fold, comparable to the iNK cell numbers found in the control arm (cultured without allogeneic PBMCs). Interestingly, pbNK cell numbers decreased, while T-cell activation and expansion remained lower than in B2M-sufficient MLR cultures. Furthermore, when B2M KO iNK cells were cocultured with tumor cells and anti-CD38 mAb in vitro, ADCC was comparable to the B2M sufficient cells, indicating uncompromised effector function. Finally, in vivo studies suggested that co-administration of anti-CD38 mAbs can significantly enhance the persistence of B2M KO iNK cells in the presence of allogeneic pbNK cells as seen in the spleen and bone marrow (Figure 1). Together these data demonstrate that the combination of triple-gene knockout of CD38, B2M and CIITA with a CD38-targeting mAb is an effective strategy to avoid host immune rejection, and highlights the potential advantages of multiplexed engineered iPSCs to facilitate large-scale manufacture of complex engineered, off-the-shelf cellular therapies. Figure 1 Figure 1. Disclosures Williams: Fate Therapeutics: Current Employment. Malmberg: Merck: Research Funding; Vycellix: Consultancy; Fate Therapeutics: Consultancy, Research Funding. Lee: Fate Therapeutics, Inc.: Current Employment. Bjordahl: Fate Therapeutics: Current Employment. Valamehr: Fate Therapeutics, Inc.: Current Employment.

scholarly journals A Bicistronic Vector Expressing CD16 and a Membrane Bound IL-15 Construct in iPSC Derived NK Cells Increased Cytotoxicity and Persistence

Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 4809-4809
Author(s):  
Alexander G Allen ◽  
Rithu Pattali ◽  
Kaitlyn M Izzo ◽  
Jared A Getgano ◽  
Kevin M Wasko ◽  
...  
Keyword(s):  
T Cells ◽  
Nk Cells ◽  
Nk Cell ◽  
Constitutive Expression ◽  
Publicly Traded ◽  
Cell Therapies ◽  
Car T Cells ◽  
Car T ◽  
Membrane Bound

Abstract Current cell and gene therapy medicines for oncology have reshaped how cancer is treated. Specifically, chimeric antigen receptor (CAR)-T cells have demonstrated that cell therapy can achieve durable remissions in hematologic malignancies. However, CAR-T cell therapies have limited efficacy in solid tumors and are often associated with severe toxicity, highlighting the need for novel cell therapies that are safer and more efficacious. With their intrinsic killing capacity of tumor cells and few, if any, treatment related toxicities, natural killer (NK) cell therapies represent an attractive alternative therapy option to CAR-T cells. In addition, NK cells can be generated from allogeneic donors and given to patients off-the-shelf without causing graft versus host disease. Of the various sources of donor types to generate NK cells from, induced pluripotent stem cells (iPSCs) have the unique advantage of being a renewable source. A clone with any desired edits to enhance the effector function of NK cells can be derived, fully characterized, and expanded indefinitely, to generate large quantities of a naturally allogeneic medicine, therefore streamlining the manufacturing process and increasing scalability. Here, a bicistronic cargo encoding CD16 and a membrane-bound IL-15 (mbIL-15) was knocked into iPSCs at the GAPDH locus using an engineered and highly active AsCas12a. The promoter at the GAPDH locus drives robust constitutive expression of inserted cargos and avoids the promoter silencing that often occurs during differentiation with other strategies. CD16 and mbIL-15 were selected as Knock-Ins (KI) to specifically enhance NK cell therapy in two areas, namely NK cell deactivation caused by CD16 downregulation, and the reliance of co-administration of cytokines such as IL-15 or IL-2 for persistence. CD16 (FcRyIII) can bind the Fc portion of IgG antibodies triggering the lysis of targeted cells. This mechanism of cytotoxicity is known as antibody dependent cellular cytotoxicity (ADCC), and is an innate immune response largely mediated by NK cells through CD16. ADCC is severely impaired when surface CD16 is cleaved by a metalloprotease known as ADAM17. By having CD16 expressed from the GAPDH locus, there is consistent CD16 protein expression to replace what is shed. This hypothesis was demonstrated by performing flow cytometry before and after a cytotoxicity assay. WT cells showed a marked reduction in the surface level expression of CD16 compared to CD16 KI cells after tumor cell exposure. Using a lactate dehydrogenase (LDH) release assay as a measure of cytotoxicity, only the iNK cells expressing the CD16 construct showed statistically significant increases in cytotoxicity when trastuzumab was added. Furthermore, to better model a solid tumor, a 3D tumor spheroid killing assay was utilized where CD16 KI cells showed an increase in ADCC capacity. The benefit of increased effector function via CD16 KI cannot be fully realized without iNK cells persisting. IL-2 or IL-15 is needed for NK maintenance but the administration of either cytokine is associated with acute clinical toxicities. mbIL-15 allows NK cells to survive for a prolonged period without the support of homeostatic cytokines. An in vitro persistence assay was performed that demonstrated IL-15 KI cells showed an increase in persistence compared to WT cells. Specifically, during the three-week in vitro assay, WT cells became undetectable by Day 14 while IL-15 KI NK cells remained stable over time. In summary, to overcome two shortfalls of NK cell therapies, a bicistronic construct encoding CD16 and a mbIL-15 was knocked into the GAPDH locus of iPSCs. The strong GAPDH promoter drove constitutive expression of CD16 that mitigated CD16 shedding, enhanced ADCC of iNK cells, which can be used in combination with any ADCC enabling IgG1 and IgG3 antibodies, such as trastuzumab and rituximab, for tumor-specific targeting. In addition, mbIL-15 KI allowed iNK cells to persist without exogenous cytokine administration and thus can circumvent exogeneous cytokine-induced clinical toxicities. CD16 and mbIL-15 double KI iNKs, with enhanced ADCC and increased cytokine-independent persistence, can potentially be developed into a safe and efficacious therapy for the treatment of a variety of liquid and solid tumors with high unmet medical needs. Disclosures Allen: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Pattali: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Izzo: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Getgano: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Wasko: Editas Medicine: Current equity holder in publicly-traded company, Ended employment in the past 24 months. Blaha: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Zuris: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Zhang: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Shearman: Editas Medicine: Current Employment, Current equity holder in publicly-traded company. Chang: Editas Medicine: Current Employment, Current equity holder in publicly-traded company.

scholarly journals Natural Killer Cells: The Linchpin for Successful Cancer Immunotherapy

2021 ◽  
Vol 12 ◽  
Author(s):  
Kari A. Shaver ◽  
Tayler J. Croom-Perez ◽  
Alicja J. Copik
Keyword(s):  
T Cells ◽  
Immune System ◽  
Nk Cells ◽  
Cancer Immunotherapy ◽  
Natural Killer ◽  
Nk Cell ◽  
Checkpoint Inhibitors ◽  
Cytotoxic T Cells ◽  
Current Evidence ◽  
Cell Therapies

Cancer immunotherapy is a highly successful and rapidly evolving treatment modality that works by augmenting the body’s own immune system. While various immune stimulation strategies such as PD-1/PD-L1 or CTLA-4 checkpoint blockade result in robust responses, even in patients with advanced cancers, the overall response rate is low. While immune checkpoint inhibitors are known to enhance cytotoxic T cells’ antitumor response, current evidence suggests that immune responses independent of cytotoxic T cells, such as Natural Killer (NK) cells, play crucial role in the efficacy of immunotherapeutic interventions. NK cells hold a distinct role in potentiating the innate immune response and activating the adaptive immune system. This review highlights the importance of the early actions of the NK cell response and the pivotal role NK cells hold in priming the immune system and setting the stage for successful response to cancer immunotherapy. Yet, in many patients the NK cell compartment is compromised thus lowering the chances of successful outcomes of many immunotherapies. An overview of mechanisms that can drive NK cell dysfunction and hinder immunotherapy success is provided. Rather than relying on the likely dysfunctional endogenous NK cells to work with immunotherapies, adoptive allogeneic NK cell therapies provide a viable solution to increase response to immunotherapies. This review highlights the advances made in development of NK cell therapeutics for clinical application with evidence supporting their combinatorial application with other immune-oncology approaches to improve outcomes of immunotherapies.

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