NK Cell Antitumor Research Articles

A Single-Cell Analysis of the NK-Cell Landscape Reveals That Dietary Restriction Boosts NK-Cell Antitumor Immunity via Eomesodermin.

Abnormal metabolism in tumor cells represents a potential target for tumor therapy. In this regard, dietary restriction (DR) or its combination with anticancer drugs is of interest as it can impede the growth of tumor cells. In addition to its effects on tumor cells, DR also plays an extrinsic role in restricting tumor growth by regulating immune cells. NK cells are innate immune cells involved in tumor immunosurveillance. However, it remains uncertain whether DR can assist NK cells in controlling tumor growth. In this study, we demonstrate that DR effectively inhibits metastasis of melanoma cells to the lung. Consistent with this, the regression of tumors induced by DR was minimal in mice lacking NK cells. Single-cell RNA sequencing analysis revealed that DR enriched a rejuvenated subset of CD27+CD11b+ NK cells. Mechanistically, DR activated a regulatory network involving the transcription factor Eomesodermin (Eomes), which is essential for NK-cell development. First, DR promoted the expression of Eomes by optimizing mTORC1 signaling. The upregulation of Eomes revived the subset of functional CD27+CD11b+ NK cells by counteracting the expression of T-bet and downstream Zeb2. Moreover, DR enhanced the function and chemotaxis of NK cells by increasing the accessibility of Eomes to chromatin, leading to elevated expression of adhesion molecules and chemokines. Consequently, we conclude that DR therapy enhances tumor immunity through nontumor autonomous mechanisms, including promoting NK-cell tumor immunosurveillance and activation.

Enhanced IL-15-mediated NK cell activation and proliferation by an ADAM17 function-blocking antibody involves CD16A, CD137, and accessory cells

BackgroundNatural killer (NK) cells are being extensively studied as a cell therapy for cancer. These cells are activated by recognition of ligands and antigens on tumor cells. Cytokine therapies, such...

YF550-C1, an E3 ligase inhibitor of CBL-B, to demonstrate T cell and NK cell activation and anti-tumor activities in syngeneic and PDX tumor model.

e14570 Background: Casitas B-lineage lymphoma b (CBL-B) is one of ligase in E3 ubiquitin family, which mainly expressed in matured hematopoietic cells, including T and NK cells. Study showed that CBL-B deficiency upregulated interleukin-2 and interferon-gamma secretion during anti-CD3 and anti-CD28 stimulated TCR activation, even without co-stimulator anti-CD28[3]. Except T cells, CBL-B plays important role in NK cells as well. CBL-B was upregulated during NK cell activation. While downregulation of CBL-B enhanced the cytotoxicity of primary human NK cells against hematological cancer cell lines. In vivo studies proved that CBL-B deficiency protected mice from tumor growth by inducing antitumor immunity. Thus, CBL-B shows a promising target for cancer therapy. Methods: We developed a small molecule YF550-C1 that targeted CBL-B, and evaluated the activation on T cell and NK cell function, and the therapeutical effect on syngeneic tumor models. The T cell activation was indicated by levels of IL-2 and IFN-γ from CBL-B knockout or WT CD8+ T cells since stimulated with anti-CD3 or anti-CD3/28 for 48 hours. The resistance of PGE2-induced immunosuppressive was evaluated by measuring IL-2 and IFN-γ since human T cells treated with PGE2 and followed by series diluted YF550-C1 or comparable inhibitor cpd23. OVA specific antigen stimulated CD8+ T activation assay was conducted by coculture OT-1 CD8+ T cells and WT DC cells with 50:1 for 72 hours in the present of 5ug/ml OVA peptide and series diluted YF550-C1. The NK cell cytotoxicity was evaluated by co-culture human NK cells and K562-luc cells with 1.25:1 ratio in the present of 1000nM or 333nM YF550-C1, which indicated by luminance. Syngeneic mouse model that inoculated with different types of murine cancer cell lines was used to evaluate tumor growth. Results: CBL-B deficiency suppressed tumor growth in mouse tumor models and enhanced cytokines release in T cells upon TCR engagement. CBL-B inhibitor, YF550-C1, alleviated PGE2-mediated immunosuppression of human T cell activation. CBL-B inhibitor, YF550-C1, enhanced OVA-specific antigen stimulated CD8+ T cell activation. CBL-B inhibitor, YF550-C1, enhanced cytotoxicity of human NK cell against K562-luc cells. CBL-B inhibitor, YF550-C1, or in combinate with anti-PD-L1 suppressed tumor growth in syngeneic tumor models. Single-agent of CBL-B inhibitor YF550-C1 treatment was sufficient to suppress PD1/PD-L1 resistant NSCLC patient-derived tumor growth. Conclusions: These studies provided insight into the activity of the inhibitor of CBL-B, demonstrating that YF550-C1 displays excellently T cell activation, T cell immunosuppression alleviation, NK cell activation and antitumor activity in multiple preclinical tumor models. Our data showed that YF550-C1 is a promising candidate for cancer treatment as monotherapy or in combination with PD-L1 blockade.

Abstract 2375: 23ME-01473, a novel anti-ULBP6/2/5 monoclonal antibody, reinvigorates anti-tumor NK cell function through NKG2D and FcγRIIIa activation

Abstract Using genome-wide association studies (GWAS) of the 23andMe genetic and healthy survey database across all phenotypes as part of our unique target discovery platform, we identified immuno-oncology (I/O)-related genetic variants as those with opposing directionality of effects on cancer and immunological phenotypes, which comprise the I/O signature. This I/O signature identified ULBP6 as a potential cancer therapeutic target. ULBP6 is a stress-induced cell surface ligand found on cancer cells, that binds to the activating receptor, NKG2D, on NK and T cells to induce tumor cell killing. However, as a mechanism of immune escape, tumors shed ULBP6 to produce a soluble form that attenuates NKG2D activation and is elevated in cancers. Given that the 2 allelic variants of ULBP6 have the highest binding affinity to NKG2D of all human NKG2D ligands, ULBP6 may be the most immunosuppressive soluble NKG2D ligand and a critical regulator of anti-tumor response. Accordingly, soluble ULBP6 exhibited significant suppression of IFNγ release and detectable cell surface NKG2D expression on healthy donor PBMCs using in vitro cell-based assays. Moreover, the overexpression of human ULBP6 in a genetically modified MC38 murine model resulted in decreased infiltration of NK, NKT, and CD8 T cells in vivo. As such, we developed a novel humanized monoclonal antibody, 23ME-01473, that binds with high affinity to ULBP6, and due to the high sequence homology, to ULBP2 and ULBP5, to block their interaction with NKG2D. By preventing the binding of soluble ULBP6 to NKG2D on PBMCs in vitro, 23ME-01473 restored NKG2D activation as measured by increased detectable cell surface NKG2D expression, IFNγ and granzyme B release, and tumor cell killing by PBMCs. To further leverage the binding of 23ME-01473 to ULBP6/2/5, 23ME-01473 was designed to have an afucosylated Fc domain that enhances its binding affinity to the activating Fc receptor, FcγRIIIa, on NK cells to induce ADCC against tumor cells. The combination of NKG2D and FcγRIIIa activation resulted in synergistic PBMC-mediated IFNγ secretion and enhanced tumor cell killing, compared to activation of either NKG2D or FcγRIIIa. Taken together, these results reveal ULBP6 as a novel cancer therapeutic target, and given the dual activation of NKG2D and FcγRIIIa, suggest the potential of 23ME-01473 to activate NK cells and elicit anti-tumor immunity. Citation Format: Joel Benjamin, Abigail Jarret, Shashank Bharill, Shruti Yadav, Dina Ayupova, Clifford Hom, Zahra Bahrami Dizicheh, I-Ling Chen, Anh Diep, Shi Shi, Caroline Bonnans, Danielle Kellar, Germaine Fuh, Maike Schmidt, Kimberline Gerrick, Patrick Koenig, Mauro Poggio. 23ME-01473, a novel anti-ULBP6/2/5 monoclonal antibody, reinvigorates anti-tumor NK cell function through NKG2D and FcγRIIIa activation [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2375.

The ω-3 Polyunsaturated Fatty Acid Docosahexaenoic Acid Enhances NK-Cell Antitumor Effector Functions.

ω-3 polyunsaturated fatty acids (PUFA) are known to directly repress tumor development and progression. In this study, we explored whether docosahexaenoic acid (DHA), a type of ω-3 PUFA, had an immunomodulatory role in inhibiting tumor growth in immunocompetent mice. The number of natural killer (NK) cells but not the number of T or B cells was decreased by DHA supplementation in various tissues under physiologic conditions. Although the frequency and number of NK cells were comparable, IFNγ production by NK cells in both the spleen and lung was increased in DHA-supplemented mice in the mouse B16F10 melanoma tumor model. Single-cell RNA sequencing revealed that DHA promoted effector function and oxidative phosphorylation in NK cells but had no obvious effects on other immune cells. Using Rag2-/- mice and NK-cell depletion by PK136 antibody injection, we demonstrated that the suppression of B16F10 melanoma tumor growth in the lung by DHA supplementation was dependent mainly on NK cells. In vitro experiments showed that DHA directly enhanced IFNγ production, CD107a expression, and mitochondrial oxidative phosphorylation (OXPHOS) activity and slightly increased proliferator-activated receptor gamma coactivator-1α (PGC-1α) protein expression in NK cells. The PGC-1α inhibitor SR-18292 in vitro and NK cell-specific knockout of PGC-1α in mice reversed the antitumor effects of DHA. In summary, our findings broaden the current knowledge on how DHA supplementation protects against cancer growth from the perspective of immunomodulation by upregulating PGC-1α signaling-mediated mitochondrial OXPHOS activity in NK cells.

Efficacy of natural killer cell therapy combined with chemoradiotherapy in murine models of head and neck squamous cell carcinoma

Background aimsNatural killer (NK) cell-based cancer immunotherapy is effective when combined with other treatment modalities such as irradiation and chemotherapy. NK cell's antitumor function to treat solid tumor, including head and neck squamous cell carcinoma (HNSCC), has been targeted recently. This study assessed NK cell recruitment in response to chemoradiation therapy (CRT) in HNSCC. MethodsEx vivo expansion of NK cell, flow cytometry, cell viability assay, cytotoxicity assay, immunohistochemistry, and animal model were performed. ResultsMouse NK cells were recruited to the tumor site by CRT in a nude mouse model. Furthermore, expanded and activated human NK cells (eNKs) were recruited to the tumor site in response to CRT, and CRT enhanced the anti-tumor activity of eNK in an NOD/SCID IL-2Rγnull mouse model. Various HNSCC cancer cell lines exhibited different NK cell ligand activation patterns in response to CRT that correlated with NK cell-mediated cytotoxicity. ConclusionsIdentifying the activation patterns of NK cell ligands during CRT might improve patient selection for adjuvant NK cell immunotherapy combined with CRT. This is the first study to investigate the NK cell's antitumor function and recruitment with CRT in HNSCC mouse model.

Crosstalk between NFAT and NFκB Signaling Regulates NK Cell Immunosurveillance

One of the major transcriptional regulators in lymphoid cells is NFAT (Nuclear Factor of Activated T Cells), controlling lymphocyte development and activity. The role of NFAT signaling is well defined in T cells, the cytotoxic lymphocytes of the adaptive immunity. However, surprisingly little is known regarding the relevance of this transcription factor family in NK cells as effector cells of the innate immunity. Available data indicate that NFAT activity is dispensable for development of NK cells, whereas effects of the immunosuppressive drugs cyclosporin A and tacrolimus, that inhibit calcineurin and consecutively NFAT, implicate an involvement of the NFAT family in NK cell function. We here employed different genetic mouse models and functional analyses to unravel the role of NFAT1 (NFATc2) and NFAT2 (NFATc1) in NK cell reactivity. In vitro knockout (KO) of NFAT1 (NFATc2) or NFAT2 (NFATc1) enhanced NK cell degranulation and resulted in increased production of granzyme B and perforin upon stimulation of activating receptors like NK1.1 or Nkp46 or upon co-culture with different leukemia and solid tumor cells. In line, cytotoxicity assays revealed increased lysis of YAC-1 and B16F10 tumor cells by both NFAT1- and NFAT2-deficient NK cells as compared to wildtype (WT) controls. The inhibitory effect of NFAT transcription factors on NK cell effector function could also be confirmed in vivo by employing WT and NFAT KO animals in syngeneic B16F10 melanoma, RMA-S lymphoma and LL/2-luc lung carcinoma models, which revealed a significantly reduced tumor burden in NFAT1 and NFAT2 KO mice. Furthermore, we detected higher numbers of tumor infiltrating NK cells in NFAT KO mice, which suggested improved NK cell migration and homing to the tumor side. Comparative analyses with single NFAT as well as NFAT1+NFAT2 double KO and WT animals further confirmed the inhibitory effect of NFAT1 and NFAT2 and pointed to additive effects of NFAT1 and NFAT2 in NK cell tumor immunosurveillance. Proteomics analysis of NK cells from the different NFAT KO strains revealed altered expression of molecules which are regulating chemokine receptor expression as well as a decreased expression of NFκB inhibitory molecules, like NFKBIB (NFKB inhibitor beta) Commd6 (COMM domain containing 6). NFκB signaling was shown to regulate granzyme B and perforin synthesis and expression. Thus, we suggest that NFAT1 and NFAT2 inhibit NFκB signaling in NK cells, and NFAT1 and NFAT2 KO reinforce NFκB induced granzyme B and perforin expression and thereby increase NK cell cytotoxicity. Taken together, our results identify NFAT as a negative regulator of NK cell function. In addition, we provide the first evidence for a direct functional involvement of NFAT1 and NFAT2 in NK cell antitumor reactivity by regulation tumor infiltration and cytotoxicity of NK cell.

Vitamin B6 Competition in the Tumor Microenvironment Hampers Antitumor Functions of NK Cells.

The nutrient competition among the different tumor microenvironment components drives tumor growth, immune tolerance, and therapeutic resistance. PDAC cells demand a high amount of VB6, thus competitively causing NK-cell dysfunction. Supplying VB6 with blocking VB6-dependent one-carbon metabolism amplifies the NK-cell antitumor immunity and inhibits tumor growth in PDAC models. This article is featured in Selected Articles from This Issue, p. 5.

Yeast β-glucan modulates macrophages and improves antitumor NK-cell responses in cancer.

As the largest proportion of myeloid immune cells in tumors, macrophages play an important role in tumor growth and regression according to their different phenotypes, thus reprogramming macrophages has become a new research direction for cancer immunotherapy. Yeast-derived whole β-glucan particles (WGPs) can induce M0 macrophages to differentiate into M1 macrophages and convert M2 macrophages and tumor-associated macrophages (TAMs) into M1 macrophages. In vitro, studies have confirmed that WGP-treated macrophages increase the activating receptors in natural killer cells (NK cells) and enhance the cytotoxicity of NK cells. The extracellular regulated protein kinases (ERK) signaling pathway is involved in WGP-mediated regulation of the macrophage phenotype. Further in vivo studies show that oral WGP can significantly delay tumor growth, which is related to the increased proportion of macrophages and NK cells, the macrophage phenotype reversal, and the enhancement of NK cell immune function. NK-cell depletion reduces the therapeutic efficacy of WGP in tumor-bearing mice. These findings revealed that in addition to T cells, NK cells also participate in the antitumor process of WGP. It was confirmed that WGP regulates the macrophage phenotype to regulate NK-cell function.

T-BET and EOMES sustain mature human NK cell identity and antitumor function.

Since the T-box transcription factors (TFs) T-BET and EOMES are necessary for initiation of NK cell development, their ongoing requirement for mature NK cell homeostasis, function, and molecular programming remains unclear. To address this, T-BET and EOMES were deleted in unexpanded primary human NK cells using CRISPR/Cas9. Deleting these TFs compromised in vivo antitumor response of human NK cells. Mechanistically, T-BET and EOMES were required for normal NK cell proliferation and persistence in vivo. NK cells lacking T-BET and EOMES also exhibited defective responses to cytokine stimulation. Single-cell RNA-Seq revealed a specific T-box transcriptional program in human NK cells, which was rapidly lost following T-BET and EOMES deletion. Further, T-BET- and EOMES-deleted CD56bright NK cells acquired an innate lymphoid cell precursor-like (ILCP-like) profile with increased expression of the ILC-3-associated TFs RORC and AHR, revealing a role for T-box TFs in maintaining mature NK cell phenotypes and an unexpected role of suppressing alternative ILC lineages. Our study reveals the critical importance of sustained EOMES and T-BET expression to orchestrate mature NK cell function and identity.

AATF/Che-1 RNA polymerase II binding protein overexpression reduces the anti-tumor NK-cell cytotoxicity through activating receptors modulation.

AATF/Che-1 over-expression in different tumors is well known and its effect on tumorigenicity is mainly due to its central role demonstrated in the oncogenic pathways of solid tumors, where it controls proliferation and viability. The effect exerted by tumors overexpressing Che-1 on the immune response has not yet been investigated. Starting from ChIP-sequencing data we confirmed Che-1 enrichment on Nectin-1 promoter. Several co-cultures experiments between NK-cells and tumor cells transduced by lentiviral vectors carrying Che-1-interfering sequence, analyzed by flow-cytometry have allowed a detailed characterization of NK receptors and tumor ligands expression. Here, we show that Che-1 is able to modulate the expression of Nectin-1 ligand at the transcriptional level, leading to the impairment of killing activity of NK-cells. Nectin-1 down-modulation induces a modification in NK-cell ligands expression able to interact with activating receptors and to stimulate NK-cell function. In addition, NK-cells from Che-1 transgenic mice, confirming a reduced expression of activating receptors, exhibit impaired activation and a preferential immature status. The critical equilibrium between NK-cell ligand expression on tumor cells and the interaction with NK cell receptors is affected by Che-1 over-expression and partially restored by Che-1 interference. The evidence of a new role for Che-1 as regulator of anti-tumor immunity supports the necessity to develop approaches able to target this molecule which shows a dual tumorigenic function as cancer promoter and immune response modulator.

Correlation of low B7-H6 expression with efficacy of immunotherapy inpatients with melanoma.

e21556 Background: B7-H6 (NCR3LG1) can bind to NKp30 to trigger antitumor NK cell activation and cytokine secretion. Our previous studies have shown that in gastric cancer, B7-H6 high expression was associated with better prognosis and the low expression of B7-H6 group was correlated with better immune microenvironment. However, the effect of B7-H6 expression on immunotherapy is unknown. Herein, we used the data from a clinically annotated cohort of melanoma patients treated with ICI to analyze the influence of B7-H6 expression on immunotherapy. Methods: The gene expression profile, gene mutation information and clinical data were extracted from the supplementary data in melanoma cohort (PMID: 31792460). Maximally selected rank statistics was used to select the optimum threshold for B7-H6 expression, and the patients was divided into two groups according to the expression of B7-H6, high group and low group. Kaplan-Meier survival analysis was used to evaluate the influence of B7-H6 expression on OS prognosis. Associations between variables and OS survival were tested using univariate and multivariate Cox and displayed by forest (R package). Results: We selected 3.14 as the optimum threshold of B7-H6 expression, and the patients was divided into high group (B7-H6 expression＞3.14) and low group (B7-H6 expression≤3.14). The results showed that low group was significantly associated with longer overall survival (p value = 0.048) in cohort of melanoma patients treated with anti-PD1 ICI, which was consistent with our previous results that low expression of B7-H6 group was correlated with better immune microenvironment. We selected primary lesion type, TMB and the expression of B7-H6 factors for univariate and multivariate analysis. TMB-H (top 25%) (p value = 0.051) and B7-H6 (p value = 0.051) low expression were associated with a better OS. Then the patients were divided into four groups according to the TMB and B7-H6 expression and analyzed the difference in the four groups. The results showed that in patients with TMB-L, B7-H6 low group had significant better OS than the B7-H6 high group (p value = 0.032). Conclusions: The low B7-H6 expression was correlated with better efficacy immunotherapy. The effect of B7-H6 expression on immunotherapy needs to be further prospective trial validation.

Systems approaches to characterize the local heterogeneities in NK cell antitumor immunity in MHC I-disparate human non-small cell lung cancer

Abstract Checkpoint immunotherapy has shown encouraging yet limited success in non-small cell lung cancer (NSCLC) patients. We combined multiplexed fluorescence imaging with quantitative spatial analysis to investigate antitumoral immunity in NSCLC. As seen before, we observed frequent MHC class I (MHC I) loss and development of CD8 T cell refractory tumors. MHC I-deficiency suggested NK cells may confer protection in NSCLC. Indeed, we found higher CD3 −CD56 +NK cell numbers were associated with both disease-free and overall survival. Using partial least squares regression, we found that both T cells and NK cells were significantly enriched in MHC I-bearing tumors. Quantitative spatial characterization of tumor cell MHC I expression revealed vast intra- and inter-tumoral heterogeneity, which was highly associated with the local lymphocyte landscape. To infer functional differences in local cell-cell communication, we built computational models based on spatial single cell neighborhood profiles to discriminate between IFNg-disparate lymphocytes. We found IFNg +NK cells more frequently associated with other IFNg +NK cells or T cells in comparison to IFNg −NK cells, or IFNg +T cells which more frequently had IFNg −lymphocyte neighbors. Moreover, IFNg +NK cells were unique in their capacity to also associate with MHC I −tumor cells. Together these data implicate a key role for NK cells in recruiting and activating other lymphocytes in MHC I-bearing tumors, and further suggest NK cells may be key to developing effective therapies even in CD8 T cell refractory tumors. Supported by UVA Carter Immunology Center Collaborative Research Award

Abstract 2940: Use of NK humanized mouse models for the in vivo evaluation of anti-tumor NK-cell therapies

Abstract Novel immunotherapeutic strategies targeting human Natural Killer (huNK) cells using monoclonal or multi-specific antibodies and immune modulator molecules are under development and there is a pressing need to have suitable mouse models for the evaluation of these therapeutics. Existing humanized mouse models have limitations and do not show an optimal development of innate immune cells such as NK, dendritic or other myeloid cells. We previously described the development of robust mouse models that allow the engraftment and maintenance of fully functional huNK cells using several strains of immunodeficient transgenic mice for human cytokines (IL-15). The optimal parameters (source of immune cells, pre-conditioning regimen, route of administration) were identified, and the models were validated by flow cytometry and in vivo efficacy studies using an anti-CD20 Ab. Here, we report further development and characterization of these models and highlight their value to evaluate a variety of NK based therapeutics. We show that huNK cells can infiltrate a subcutaneous B-cell lymphoma model after treatment with an anti-CD20 Ab. We show that SAR444245 (non-alpha IL2) can activate huNK cells in vivo in all developed huIL-15 transgenic models and confirmed the minimal effective dose by flow-cytometry PD studies. We show the efficacy of both reference and internal ADCC-enhanced antibodies in disseminated tumor models in our humanized huIL-15 transgenic mice. In addition, we performed a deep characterization of huNK cells in huIL-15 transgenic models, using a 28-color flow cytometry panel centered on NK cell biology and profiled them transcriptionally by single cell RNA Seq in a disseminated B-cell lymphoma model. Overall, we have developed robust models sustaining fully functional huNK cells that can be proficiently recruited in vivo by various NK-based therapeutics and can be used to evaluate the efficacy of combination therapies. Citation Format: Pauline Rettman, Laure-Marie Meyer, Ravi Rangara, Anna Ponchet-Lac, Nicolas Moindrot, Angélique Biancotto, Céline Lefranc, Fabien Delahaye, Emilia Rabia, Matteo Cesaroni, Sukhvinder Sidhu, Céline Nicolazzi. Use of NK humanized mouse models for the in vivo evaluation of anti-tumor NK-cell therapies [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 2940.

The tumor microenvironment drives NK cell metabolic dysfunction leading to impaired antitumor activity.

NK cells represent key players capable of driving antitumor immune responses. However, the potent immunosuppressive activity of the tumor microenvironment (TME) may impair their effector function. Here, we strengthen the importance of metabolic interactions between NK cells and TME and propose metabolic dysfunction as one of the major mechanisms behind NK failure in cancer treatment. In particular, we described that TME has a direct negative impact on NK cell function by disrupting their mitochondrial integrity and function in pediatric and adult patients with primary and metastatic cancer. Our results will help to design new strategies aimed at increasing the NK cell antitumor efficacy by their metabolic reprogramming. In this regard, we reveal an unprecedented role of IL15 in the metabolic reprogramming of NK cells enhancing their antitumor functions. IL15 prevents the inhibitory effect of soluble factors present in TME and restores both the metabolic characteristics and the effector function of NK cells inhibited by exposure to malignant pleural fluid. Thus, we propose here that IL15 may be exploited as a new strategy to metabolically reprogram NK cells with the aim of increasing the efficacy of NK-based immunotherapy in a wide range of currently refractory adult and pediatric solid tumors.

PRODUCTION AND LARGE-SCALE EXPANSION OF FUNCTIONALLY ACTIVE NK CELLS SUITABLE FOR USE IN IMMUNOTHERAPY OF HEMATOLOGICAL AND SOLID TUMORS

Natural killer cells (NK) are part of the innate immune system of the body and play an important role in the immune surveillance of foreign cells and the body’s own altered cells, including the transformed ones. The NK cells, without prior stimulation, can eliminate target cells which do not express their own MHC class I molecules or express stress-induced molecules. These basic, natural functions of the NK cells as a tool in the fight against malignant tumors have attracted particular attention. For this purpose, various approaches are used to increase the number and/or enhance the functional activity of the NK cells. One approach uses cytokines to selectively increase both the number and effectiveness of the NK cell antitumor function. Another approach focuses on checkpoint inhibitors targeting the NK cell receptor. Bispecific and trispecific activators have been developed to enhance the specific immune response by cross-linking specific tumor antigens with effector cells. In addition, methods of adoptive transfer of the NK cells have shown promising results, however, a fairly large volume of cell mass is required there.

A Sampling of Highlights from the Literature

What We're Reading| July 01 2022 A Sampling of Highlights from the Literature: Article Recommendations from Our Deputy and Senior Editors Author & Article Information Online Issn: 2326-6074 Print Issn: 2326-6066 ©2022 American Association for Cancer Research2022American Association for Cancer Research Cancer Immunol Res (2022) 10 (7): 785. https://doi.org/10.1158/2326-6066.CIR-10-7-WWR Views Icon Views Article contents Figures & tables Video Audio Supplementary Data Peer Review Share Icon Share MailTo Twitter LinkedIn Tools Icon Tools Get Permissions Cite Icon Cite Search Site Article Versions Icon Versions Version of Record July 1 2022 Citation A Sampling of Highlights from the Literature: Article Recommendations from Our Deputy and Senior Editors. Cancer Immunol Res 1 July 2022; 10 (7): 785. https://doi.org/10.1158/2326-6066.CIR-10-7-WWR Download citation file: Ris (Zotero) Reference Manager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest Search Advanced Search A new cancer vaccine induces T-cell and NK-cell antitumor immunity (from Brenda Melendez and Rita Serda, via NIH Flickr) Most cancer vaccines being developed boost T-cell responses through immunization with tumor antigens. Badrinath and colleagues report the development and preclinical characterization of a new vaccine that induces the production of antibodies specific for the α3 domain of MHC class I chain-related protein A and B (MICA/B), stress proteins expressed by many cancers. The antibodies prevent proteolytic shedding of MICA/B, leading to enhanced NK-cell cytotoxicity and increased cross presentation of tumor antigens to CD8+ T cells by type 1 conventional dendritic cells (cDC1). The vaccine reduces growth and metastasis of mouse tumors, including MHC class I–deficient tumors resistant to CTLs, highlighting the potential of this vaccine approach to overcome tumor escape from peptide-based cancer vaccines. Badrinath S, …, Wucherpfennig KW. Nature 2022 May 25. DOI:10.1038/s41586–022–04772–4. Cells and their interactions may not... You do not currently have access to this content.

TGFβ and CIS Inhibition Overcomes NK-cell Suppression to Restore Antitumor Immunity.

Antibodies targeting "immune checkpoints" have revolutionized cancer therapy by reactivating tumor-resident cytotoxic lymphocytes, primarily CD8+ T cells. Interest in targeting analogous pathways in other cytotoxic lymphocytes is growing. Natural killer (NK) cells are key to cancer immunosurveillance by eradicating metastases and driving solid tumor inflammation. NK-cell antitumor function is dependent on the cytokine IL15. Ablation of the IL15 signaling inhibitor CIS (Cish) enhances NK-cell antitumor immunity by increasing NK-cell metabolism and persistence within the tumor microenvironment (TME). The TME has also been shown to impair NK-cell fitness via the production of immunosuppressive transforming growth factor β (TGFβ), a suppression which occurs even in the presence of high IL15 signaling. Here, we identified an unexpected interaction between CIS and the TGFβ signaling pathway in NK cells. Independently, Cish- and Tgfbr2-deficient NK cells are both hyperresponsive to IL15 and hyporesponsive to TGFβ, with dramatically enhanced antitumor immunity. Remarkably, when both these immunosuppressive genes are simultaneously deleted in NK cells, mice are largely resistant to tumor development, suggesting that combining suppression of these two pathways might represent a novel therapeutic strategy to enhance innate anticancer immunity.

Abstract 2104: NK cell immunosurveillance of tumors is regulated by NFAT1 and NFAT2

Abstract NK cells are lymphoid components of innate immunity and play an important role in tumor immunosurveillance. One of the major transcriptional regulators in lymphoid cells is NFAT (Nuclear Factor of Activated T cells), controlling lymphocyte development and activity. However, while the role of NFAT signaling is well defined in T cells, the cytotoxic lymphocytes of adaptive immunity, surprisingly little is known regarding the relevance of this transcription factor family in NK cells as effector cells of innate immunity. Available data indicate that NFAT activity is dispensable for development of NK cells. However, several lines of evidence including reports on the effects of the immunosuppressive drugs cyclosporin A and tacrolimus, which mediate their effects through inhibition of calcineurin and consecutively NFAT, implicate an involvement of the NFAT family in NK cell function. We here employed different genetic mouse models to unravel the role of NFAT1 (NFATc2) and NFAT2 (NFATc1) in NK cell reactivity. When NK cells with knockout (KO) of NFAT1 or NFAT2 compared to NK cells of control mice (WT) were employed in in vitro analyses, lack of either NFAT was found to surprisingly result in enhanced NK cell degranulation as well as increased production of granzyme B and perforin upon stimulation of activating receptors like NK1.1 or Nkp46 or upon co-culture with different leukemia and solid tumor tumor cells. In line, cytotoxicity assays revealed increased lysis of YAC-1 and B16F10 tumor cells by both NFAT1- and NFAT2-deficient NK cells as compared to WT controls. The inhibitory effect of NFAT transcription factors on NK cell effector function could also be confirmed in vivo by employing WT and NFAT KO animals in syngeneic B16F10 melanoma and RMA-S flank tumor models, which revealed a significantly reduced tumor burden in NFAT1 and NFAT2 KO mice. Comparative analyses with single NFAT as well as NFAT1+NFAT2 double KO and WT animals further confirmed the inhibitory effect of NFAT1 and NFAT2 and pointed to additive effects of NFAT1 and NFAT2 in NK cell tumor immunosurveillance. Taken together, our results provide the first evidence for the direct functional involvement of NFAT1 and NFAT2 in NK cell antitumor reactivity and, in contrast to T and B cells, identify NFAT as a negative regulator of NK cell function. Citation Format: Melanie Märklin, Samuel Holzmayer, Kübra Kaban, Martin R. Müller, Helmut R. Salih. NK cell immunosurveillance of tumors is regulated by NFAT1 and NFAT2 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2104.

Back to the Future: Spatiotemporal Determinants of NK Cell Antitumor Function.

NK cells play a crucial role in host protection during tumorigenesis. Throughout tumor development, however, NK cells become progressively dysfunctional through a combination of dynamic tissue-specific and systemic factors. While a number of immunosuppressive mechanisms present within the tumor microenvironment have been characterized, few studies have contextualized the spatiotemporal dynamics of these mechanisms during disease progression and across anatomical sites. Understanding how NK cell immunosuppression evolves in these contexts will be necessary to optimize NK cell therapy for solid and metastatic cancers. Here, we outline the spatiotemporal determinants of antitumor NK cell regulation, including heterogeneous tumor architecture, temporal disease states, diverse cellular communities, as well as the complex changes in NK cell states produced by the sum of these higher-order elements. Understanding of the signals encountered by NK cells across time and space may reveal new therapeutic targets to harness the full potential of NK cell therapy for cancer.