CRISPR Screens Identify Mechanisms of Natural Killer Cell Evasion across Blood Cancers

Natural killer (NK) cells have been suggested to control progression and relapse in several hematological malignancies. Enhancing NK cell reactivity represents an attractive approach to improve treatment responses. However, mechanisms enabling evasion of hematologic cancer cells from NK cells are incompletely understood. To identify cancer cell-intrinsic factors enabling resistance to NK cell cytotoxicity, we conducted genome-wide CRISPR screens in a range of hematological malignancies. Cas9-expressing cancer cells from diverse hematological malignancies, including acute and chronic myeloid leukemia (AML and CML), multiple myeloma (MM), diffuse large B-cell lymphoma (DLBCL), and B cell acute lymphoblastic leukemia were infected with a genome-scale lentiviral sgRNA library and exposed to primary human NK cells. Genes essential for NK cell cytotoxicity were discovered from surviving cancer cells which were enriched with gene knockouts inducing reduced sensitivity to NK cell killing. Additional data from a gain-of-function screen using a genome-scale CRISPR activation system were generated using the MM.1S myeloma cell line. Results from the functional genomic screens were integrated with transcriptomic data from > 9,000 patients across hematological cancers, as well as multi-omics data from AML and DLBCL, and both public and in-house single-cell RNA-sequencing data from AML patients. Knockout of genes encoding components involved in antigen presentation (B2M, HLA-A, HLA-C, HLA-E, TAP1, TAP2) sensitized multiple blood cancer cell lines to NK cell cytotoxicity, consistent with the inhibitory effect of MHC I on NK cells. Furthermore, knockout of interferon and JAK-STAT signaling components sensitized cancer cells to NK cell lysis, suggesting that MHC class I induction in response to interferon promotes NK cell resistance across cancer types. Interestingly, genes and pathways whose disruption conferred resistance for NK cell-mediated lysis exhibited partial overlap but also substantial variability across blood cancer types. Knockout of NCR3LG1 (B7-H6, ligand for the NKp30 activating NK cell receptor), resulted in resistance of K562 CML cells to NK cell cytotoxicity. In contrast, disruption of genes encoding apoptotic mediators (FADD, PMAIP1, BID) and TRAIL receptors (TNFRSF10B) conferred resistance to NK cell cytotoxicity in SUDHL4 DLBCL cells. The same pathways were identified in the MM cell line MM.1S, in which knockout of FAS, CASP2, and CASP8 as well as the TRAIL receptor TNFRSF10A induced NK cell resistance. Furthermore, loss of CD48, a ligand of the non-MHC binding receptor CD244 on NK cell surface, resulted in resistance and a genome-scale CRISPR gain-of-function screen in the same cell line showed sensitization upon CD48 overexpression. A CRISPR screen in the AML cell line MOLM14 identified disruption of TNFRSF1B encoding TNFR2 as strongly conferring NK cell resistance. Interestingly, TNFRSF1B overexpression sensitized the MM cell line MM.1S to NK cell treatment in the gain-of-function screen. Integration with genomic data from patients with hematological malignancies revealed selective expression of TNFRSF1B in AML. Within AML, TNFRSF1B expression was enriched in myelomonocytic and monocytic subtypes as well as in MLL-rearranged cases represented by the MOLM14 cell line. Further dissection at the single-cell level revealed increased expression of TNFRSF1B with differentiation of AML cells along the monocytic lineage. Consistently, the less differentiated MOLM13 cell line established from the same patient as MOLM14 was resistant to NK cell killing, suggesting that a less differentiated phenotype of AML cells confers resistance to NK cell cytotoxicity through lack of TNFRSF1B expression. Our data suggest that different lineages of hematological malignancies may be susceptible to NK cells through distinct mechanisms. In some cases, this heterogeneity is governed by lineage-specific expression of susceptibility genes, such as TNFRSF1B in monocytic AML. Particularly, our data identify a mechanism of NK cell evasion in less differentiated AML cells, suggesting potential for enhancing immune clearance of AML cells through differentiating therapies. figure Disclosures Lee: Kiadis Pharma: Consultancy, Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties, Research Funding. Mitsiades:Takeda: Other: employment of a relative ; Ionis Pharmaceuticals: Honoraria; Fate Therapeutics: Honoraria; Arch Oncology: Research Funding; Sanofi: Research Funding; Karyopharm: Research Funding; Abbvie: Research Funding; TEVA: Research Funding; EMD Serono: Research Funding; Janssen/Johnson & Johnson: Research Funding. Mustjoki:BMS: Honoraria, Research Funding; Novartis: Research Funding; Pfizer: Research Funding.

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α-Pinene Enhances the Anticancer Activity of Natural Killer Cells via ERK/AKT Pathway

International Journal of Molecular Sciences ◽

10.3390/ijms22020656 ◽

2021 ◽

Vol 22 (2) ◽

pp. 656

Author(s):

Hantae Jo ◽

Byungsun Cha ◽

Haneul Kim ◽

Sofia Brito ◽

Byeong Mun Kwak ◽

...

Keyword(s):

Nk Cells ◽

Cancer Cells ◽

Natural Killer ◽

Nk Cell ◽

Granzyme B ◽

Akt Pathway ◽

Cell Cytotoxicity ◽

Anticancer Effects ◽

Nk Cell Cytotoxicity

Natural killer (NK) cells are lymphocytes that can directly destroy cancer cells. When NK cells are activated, CD56 and CD107a markers are able to recognize cancer cells and release perforin and granzyme B proteins that induce apoptosis in the targeted cells. In this study, we focused on the role of phytoncides in activating NK cells and promoting anticancer effects. We tested the effects of several phytoncide compounds on NK-92mi cells and demonstrated that α-pinene treatment exhibited higher anticancer effects, as observed by the increased levels of perforin, granzyme B, CD56 and CD107a. Furthermore, α-pinene treatment in NK-92mi cells increased NK cell cytotoxicity in two different cell lines, and immunoblot assays revealed that the ERK/AKT pathway is involved in NK cell cytotoxicity in response to phytoncides. Furthermore, CT-26 colon cancer cells were allografted subcutaneously into BALB/c mice, and α-pinene treatment then inhibited allografted tumor growth. Our findings demonstrate that α-pinene activates NK cells and increases NK cell cytotoxicity, suggesting it is a potential compound for cancer immunotherapy.

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Gene Set Enrichment Analysis Suggests That Increased Rituximab-Mediated NK Cell Cytotoxicity after Vitamin D Substitution Is Driven By Upregulation of Interferon Alpha (IFN-a) Isoforms

Blood ◽

10.1182/blood-2018-99-111817 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 3696-3696

Author(s):

Konstantinos Christofyllakis ◽

Frank Neumann ◽

Stephan Stilgenbauer ◽

Dominic Kaddu-Mulindwa ◽

Evi Regitz ◽

...

Keyword(s):

Vitamin D ◽

Nk Cells ◽

Board Of Directors ◽

Research Funding ◽

Cytokine Production ◽

Nk Cell ◽

Cell Cytotoxicity ◽

Advisory Committees ◽

Vitamin D Levels ◽

Nk Cell Cytotoxicity

Abstract Introduction: We recently showed that vitamin D deficiency leads to decreased overall survival of DLBCL-patients treated with rituximab-chemotherapy (Bittenbring et al, JCO, 2014). We hypothesized that rituximab-mediated NK cell-cytotoxicity is more effective at higher vitamin D levels. This was confirmed by vitamin D substitution of healthy volunteers, which increased their rituximab-mediated cytotoxicity in vitro against the Daudi lymphoma cell line. To unveil the molecular mechanisms behind this finding, resting NK cells before and after vitamin D supplementation were isolated from those volunteers and a whole transcriptome analysis was performed. Methods: We collected PBMCs from eight healthy volunteers with vitamin D deficiency before and after vitamin D substitution to > 30 ng/ml 25-OH vitamin D3. NK cells were isolated from PBMCs by magnetic depletion of all non-NK cells. Purity of the CD16+ cells was confirmed by flow cytometry. After isolating total RNA, we performed a microarray analysis using an Affymetrix Gene-Chip 2.0 ™. The signals were normalized using the LMA algorithm. For pathway analysis, gene set enrichment analysis (GSEA) was used. A two-step approach was chosen. Firstly, we separated 7.705 genes due to their involvement in the NK cell-mediated immune response according to the Gene Ontology database, irrespective of their differential expression. This dataset was used separately for specific analysis of the NK cell-cytotoxicity pathway to increase sensitivity. Secondly, the complete data set of 48.145 genes was used in an exploratory analysis in an attempt to screen for other dysregulated pathways involved in the immune response and vitamin D homeostasis. We used gene sets provided from the Molecular Signature Database. A significance level of < 0.05 for p and False Discovery Rate (FDR) was chosen. Real-time quantitative PCR was performed to confirm the results. Results: The NK cell-associated cytotoxicity pathway was found to be significantly upregulated after restoration of normal vitamin D levels in the specific analysis. The most significantly overexpressed genes in the gene set were five IFN-α subtypes (IFN-α2, IFN-α4, IFN-α6, IFN-α7, and IFN-α10) as well as IFN-κ. The exploratory analysis showed an upregulation of the response to type I interferon pathway and regulation of type I interferon mediated signaling pathway. The most upregulated genes in those pathways were again the IFN-α subtypes mentioned above. Other pathways involved in the immune response were found to be downregulated after vitamin D substitution, like interferon gamma response; cytokine production and chemotaxis. The common denominator of these pathways was the downregulation of three toll-like receptor genes (TLR-8, TLR-7, TLR-2). Conclusion: The increased expression of specific IFN-α subtypes could explain the increased rituximab-mediated NK cell-cytotoxicity after vitamin D substitution in deficient individuals. To the best of our knowledge, this is the first study to suggest a role for vitamin D in IFN-α regulation. TLRs are known to stimulate cytokine production in NK cells including IFN-α. It can be assumed, that the observed upregulation of IFN-α genes after vitamin D substitution leads to a negative feedback on positive regulators of cytokine production like TLR, causing their downregulation once vitamin D levels are restored. This implies a comprehensive role of vitamin D in IFN-α biosynthesis in human NK cells. Disclosures Stilgenbauer: AbbVie: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Hoffmann La-Roche: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; GSK: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Amgen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Novartis: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Mundipharma: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Janssen: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Pharmcyclics: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genentech: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Gilead: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Boehringer-Ingelheim: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Sanofi: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Celgene: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding; Genzyme: Consultancy, Honoraria, Membership on an entity's Board of Directors or advisory committees, Research Funding.

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Natural Killer (NK) or NK/T Cell Lineage Large Granular Lymphocytosis Associated with Dasatinib Therapy for Philadelphia Chromosome Positive Leukemia.

Blood ◽

10.1182/blood.v112.11.933.933 ◽

2008 ◽

Vol 112 (11) ◽

pp. 933-933

Author(s):

Dong Hwan Kim ◽

Suzanne Kamel-Reid ◽

Hong Chang ◽

Robert Sutherland ◽

Chul Won Jung ◽

...

Keyword(s):

T Cell ◽

Nk Cells ◽

Cell Line ◽

Nk Cell ◽

Cell Lineage ◽

Target Cells ◽

Cell Cytotoxicity ◽

51Cr Release ◽

K562 Cell Line ◽

Nk Cell Cytotoxicity

Abstract Dasatinib, a dual tyrosine kinase inhibitor, is known to modulate or suppress T-cell activation and proliferation. We report a series of patients of chronic peripheral lymphocytosis development, identified as natural killer (NK) cells or NK/T-cells based on their large granular lymphocyte (LGL) morphologies and CD16+CD56+CD3− or CD3+ immunophenotypic profiles during dasatinib therapy. All cases that developed LGL lymphocytosis achieved optimal molecular response (8/8 in LGL+ patients vs 3/10 in LGL− patients, p=0.002). A 51Cr release assay demonstrated that NK cell cytotoxicity has been enhanced in a case of LGL lymphocytosis compared to normal healthy donors (Figure 1), and that NK cell cytotoxicity in dasatinib-responders was superior to that in non-responders (Figure 2). In summary, the present study suggests that NK or NK/T cell lineage LGL lymphocytosis develops associated with dasatinib therapy and that LGL might have a therapeutic effect on Ph+ leukemic cells. Figure 1. Cytotoxicity of NK cells isolated from the patients developing large granular lymphocytosis following dasatinib therapy as assessed by 51Cr release assays using target cells as K562 (A) and T2 cell line (B) as target cells. Figure 1. Cytotoxicity of NK cells isolated from the patients developing large granular lymphocytosis following dasatinib therapy as assessed by 51Cr release assays using target cells as K562 (A) and T2 cell line (B) as target cells. Figure 2. The result of 51Cr release assays comparing cytotoxicity of NK cells isolated from patients responding to dasatinib therapy (responder) and not responding (non-responder) following dasatinib therapy using K562 cell line as target cells. Figure 2. The result of 51Cr release assays comparing cytotoxicity of NK cells isolated from patients responding to dasatinib therapy (responder) and not responding (non-responder) following dasatinib therapy using K562 cell line as target cells.

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NK-Cells In Dasatinib-Treated Chronic Myeloid Leukemia Patients Display a Unique Phenotype Associated With Cytotoxic Potential

Blood ◽

10.1182/blood.v122.21.1475.1475 ◽

2013 ◽

Vol 122 (21) ◽

pp. 1475-1475

Author(s):

Beatriz Colom Fernandez ◽

Anna Kreutzman ◽

Valentin Garcia ◽

Maria José Requena Rodríguez ◽

Raúl Córdoba Mascuñano ◽

...

Keyword(s):

Chronic Myeloid Leukemia ◽

Nk Cells ◽

Myeloid Leukemia ◽

Research Funding ◽

Nk Cell ◽

Cell Phenotype ◽

Cell Cytotoxicity ◽

Immunomodulatory Effects ◽

Cytotoxic Potential ◽

Nk Cell Cytotoxicity

Abstract Background Dasatinib is a second-generation tyrosine kinase inhibitor (TKI), which is used successfully in the treatment of chronic myeloid leukemia (CML). Dasatinib has two unique features when compared to other TKIs (imatinib, nilotinib); first, dasatinib has a significantly shorter half-life in the plasma and second, dasatinib inhibits a wider spectrum of kinases, including several kinases known to be important in the function of the immune system (src, tec, and syk families), which are not affected by the other TKIs. Interestingly, it has been recently shown that both short-term exposure to dasatinib in vivo and long-term treatment with dasatinib improves NK-cell cytotoxicity, however, the mechanisms are not known. To study the improved cytotoxicity observed in dasatinib-treated patients, we aimed to perform a complete NK-cell phenotyping in these patients. Finally, our goal is to correlate NK-cell phenotype with NK-cell cytotoxicity, and to study the possible correlation between phenotypical changes, NK-cell function and clinical outcome. Methods This study included 19 dasatinib-treated (DA) CML patients, both first-line (n=7) and second-line (n=12). To investigate the specificity of the immunomodulatory effects of dasatinib, a control group of 9 CML patients treated with imatinib (IM) and another group of 12 healthy donors (HD) were included. Peripheral blood samples obtained before the patients took their daily drug dose were phenotyped with a comprehensive 8-color flow cytometry panel (total 32 antibodies, table 1). To study the correlation between phenotypical changes and NK-cell cytotoxicity, we performed a standard CD107 degranulation assay. Mononuclear cells were incubated for 6 hours in the presence of the target cell line K562 and a CD107 antibody. CD107 positive NK-cells were then phenotyped with the same panel of 32 antibodies. Results All results are summarized in table 1. In brief, DA- and IM-treated CML patients and HD had equal proportions of NK-cells (CD3negCD56+) of total lymphocytes. Regarding trafficking molecules, NK-cells in both DA- and IM-patients had a lower frequency of the chemokine receptor CCR7 when compared to HD. This suggests a reduction in the NK-cell population that is able to migrate to lymph nodes, and is likely caused by the disease or TKIs in general. Moreover, DA-treatment specifically decreases the expression of the homing molecule CD62L in NK-cells. In addition, NK-cells in DA-patients, when compared to IM and HD, expressed less CD11b and significantly more often CD11c and HLA-DR, which reproduce the immunophenotypic changes that typically occurs in recently activated NK-cells and has been shown to associate with improved clinical benefits. Conversely, increased expression of CD57 together with a lower frequency of CD27 and CD28 were observed in both groups of patients and were similar to those typically observed in conditions of chronic NK-cell stimulation. In contrast, DA-patients had a lower frequency of most of the studied NK-receptors (Nkp30, Nkp46, NKG2D, CD94, CD161, KIR2DL1/S1) when compared to IM and HD. This suggests that NK-cells in DA-treated patients have a more mature phenotype, which is caused by the treatment. Conclusions NK-cells in TKI-treated CML patients display a mature phenotype, which is often observed after chronic stimulation suggesting that TKIs have immunomodulatory effects on NK-cells or the disease itself causes the changes. Interestingly, NK-cells in DA-treated patients express a highly differentiated phenotype characterized by high expression of CD57, and decreased expression of Nkp30, Nkp46 and CD161. Similar changes were not seen in IM-patients or HD. It is possible that NK-cells expressing this phenotype might also represent those NK-cells that have previously been driven into clonal expansion by encounters with pathogens because of the specific immunomodulatory effects of dasatinib. This phenotype of highly mature NK-cells, which is associated with high cytolytic potential, could be responsible for the previously described enhanced NK-cytotoxicity caused by dasatinib. In accordance, our preliminary results suggest that these unique phenotypic changes observed in DA-treated patients correlates with the cytotoxic potential. Studies to correlate these results with therapy outcome are ongoing. Disclosures: Garcia: Novartis: Honoraria, Research Funding; BMS: Honoraria, Research Funding; Pfizer: Research Funding. Steegmann:Novartis: Honoraria, Research Funding, Speakers Bureau; BMS: Honoraria, Research Funding, Speakers Bureau; Pfizer: Honoraria, Research Funding, Speakers Bureau.

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Genome-Scale CRISPR Screens Identify Essential Genes for Sensitivity to Natural Killer Cells in Hematological Malignancies

Blood ◽

10.1182/blood-2018-99-117985 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 732-732

Author(s):

Olli Dufva ◽

Jay Klievink ◽

Khalid Saeed ◽

Matti Kankainen ◽

Mette Ilander ◽

...

Keyword(s):

Nk Cells ◽

Cancer Cells ◽

Cancer Cell ◽

Research Funding ◽

Hematological Malignancies ◽

Nk Cell ◽

Cell Cancer ◽

Cell Lysis ◽

Loss Of Function ◽

Genome Scale

Abstract Immunotherapy is a promising approach to improve treatment responses in hematological malignancies. Accumulating evidence suggests a role for natural killer (NK) cells in controlling hematological malignancies. However, mechanisms regulating sensitivity or resistance of hematologic cancer cells to the effector function of NK cells are incompletely understood. Here, we performed genome-scale CRISPR-Cas9 loss-of-function screens to systematically map genes that regulate sensitivity of hematologic malignancies to NK cells. To screen for genes involved in the interaction between NK and cancer cells, we infected human cancer cells expressing Cas9 with a genome-scale lentiviral guide RNA library (Figure). The resulting pool of knockout cells was exposed to NK cells expanded from peripheral blood of healthy donors. Enriched and depleted knockouts were detected by next-generation sequencing of the integrated sgRNA cassettes, enabling identification of genes conferring resistance or susceptibility to NK cell-mediated lysis. The screens were performed in cell lines from diverse hematological malignancies, including chronic myeloid leukemia (CML), B cell acute lymphoblastic leukemia, diffuse large B cell lymphoma (DLBCL), and multiple myeloma. We recovered several known mechanisms of NK cell/cancer cell interactions, demonstrating feasibility of the screening approach. Loss of genes encoding components of the MHC class I complex (B2M, HLA-A, HLA-C, HLA-E) sensitized multiple cancer cell lines to NK cell lysis, consistent with missing-self recognition. Furthermore, knockout of IFN-JAK-STAT signaling mediators led to increased tumor cell lysis, suggesting that MHC class I induction in response to NK cell-derived IFN gamma enables NK cell evasion by tumor cells. We also identified genes essential for effective NK cell-mediated lysis. NCR3LG1, encoding the B7-H6 ligand for the NKp30 activating NK cell receptor, was essential for NK cell lysis of CML cells. In contrast, knockout of apoptotic mediators and TRAIL pathway components conferred resistance to NK cell cytotoxicity in DLBCL cells, indicating heterogeneity in NK cell/cancer cell interactions between cancer types. Our data support a view that distinct mechanisms regulate sensitivity to NK cell cytotoxicity in different hematologic cancers. Importantly, our results indicate that loss-of-function mutations in the antigen-presenting machinery and the IFN-JAK-STAT pathway sensitize tumors to NK cell effector function. As alterations in these genes are associated with resistance to T cell immunotherapies such as PD-1 blockade, NK cell-based therapies could be employed to overcome resistance in these patients. In summary, we suggest that systematic identification of mechanisms governing tumor immune susceptibility has the potential to uncover novel immunotherapy targets. Figure. Figure. Disclosures Kankainen: Medix Biochemica: Consultancy. Lee:Merck, Sharp, and Dohme: Consultancy; Courier Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees; CytoSen Therapeutics: Equity Ownership, Membership on an entity's Board of Directors or advisory committees, Research Funding. Mustjoki:Pfizer: Honoraria, Research Funding; Novartis: Honoraria, Research Funding; Celgene: Honoraria; Ariad: Research Funding; Bristol-Myers Squibb: Honoraria, Research Funding.

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Preclinical Characterization of AFM26, a Novel B Cell Maturation Antigen (BCMA)-Directed Tetravalent Bispecific Antibody for High Affinity Retargeting of NK Cells Against Myeloma

Blood ◽

10.1182/blood-2018-99-118970 ◽

2018 ◽

Vol 132 (Supplement 1) ◽

pp. 1927-1927 ◽

Cited By ~ 8

Author(s):

Thorsten Ross ◽

Uwe Reusch ◽

Susanne Wingert ◽

Torsten Haneke ◽

Katja Klausz ◽

...

Keyword(s):

Nk Cells ◽

Research Funding ◽

Nk Cell ◽

Target Antigen ◽

Cell Cytotoxicity ◽

Effector Cells ◽

B Cell Maturation ◽

Copy Numbers ◽

Nk Cell Cytotoxicity

Abstract Natural killer (NK) cells are crucial effector cells of the innate immune system capable of rapidly recognizing and eliminating infected, stressed and malignant cells. NK cells are also the prime mediators of antibody-dependent cell-mediated cytotoxicity (ADCC), a potent mechanism of anti-viral immunity that has been applied to cancer therapy by targeting tumor-expressed surface antigens using monoclonal antibodies (mAbs). Classical ADCC is mediated by low affinity Fc-mediated engagement of NK cells via FcγRIIIA (CD16A) and is modulated by differences in target antigen expression levels. While high potency of therapeutic mAbs is achieved when target antigen is available at high density, potency and efficacy decrease substantially when copy numbers are low. Classical ADCC also needs to overcome the inhibitory effect of competing serum IgG and is negatively affected by a low affinity polymorphism of CD16A (158F) that is prevalent in approximately 8 of 10 individuals. Hence, classical Fc-mediated ADCC does not fully utilize the therapeutic potential of NK cell cytotoxicity. B cell maturation antigen (BCMA) has emerged as a promising target for treatment of multiple myeloma (MM) due to its near universal expression on tumor cells and restricted expression in non-malignant tissues. Numerous therapeutic approaches are currently investigated clinically and pre-clinically and target BCMA, however, none of these are aimed at fully utilizing NK cell-mediated ADCC. Low copy numbers of BCMA (approx. 40-15,000) might limit the activity of classical mAbs against BCMA, especially in the presence of high serum concentrations of paraprotein. In addition, NK cells may be ideally suited to target minimal residual disease immediately before or after autologous stem cell transplantation. Consequently, by efficiently redirecting NK cell cytotoxicity to BCMA+ myeloma, AFM26 used alone or in combination with other approaches may provide a novel, optimized treatment strategy. Here we describe development of AFM26, a BCMA and CD16A-directed tetravalent bispecific antibody that selectively engages CD16A+ effector cells, including NK cells, and is designed to overcome the limitations of classical ADCC. AFM26 is based on the recently launched Redirected, Optimized Cell Killing (ROCK) antibody platform and combines high affinity CD16A-directed effector cell engagement with IgG-like pharmacokinetics and manufacturability. We demonstrate that AFM26 interacts with NK cells with high avidity independently of CD16A polymorphism and in presence of competing IgG. NK cell-mediated lysis of BCMA+ target cell lines induced by AFM26 is largely independent of BCMA expression levels with high potency and efficacy observed at low copy numbers (<200), as confirmed by autologous lysis of primary MM cells in vitro. Despite more potent and efficacious in vitro lysis, release of inflammatory cytokines is comparable with classical antibody formats. We further demonstrate anti-tumor activity of AFM26 in combination with adoptive transfer of primary human NK cells in vivo using human IL-15-transgenic NOG mice. AFM26 therefore is a promising agent currently in preclinical development to fully unlock NK cell cytotoxicity for BCMA-directed immunotherapy of MM. Disclosures Ross: Affimed: Employment. Reusch:Affimed: Employment. Wingert:Affimed: Employment. Haneke:Affimed: Employment. Klausz:Affimed: Research Funding. Otte:Affimed: Research Funding. Schub:Affimed: Research Funding. Knackmuss:Affimed: Employment. Müller:Affimed: Employment. Ellwanger:Affimed: Employment. Fucek:Affimed: Employment. Schniegler-Mattox:Affimed: Employment. Koch:Affimed GmbH: Employment. Valerius:Affimed: Research Funding. Gramatzki:Affimed: Research Funding. Peipp:Affimed: Research Funding. Tesar:Affimed: Employment. Rajkovic:Affimed: Employment. Treder:Affimed GmbH: Employment.

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Roles of NK Cell Receptors 2B4 (CD244), CS1 (CD319), and LLT1 (CLEC2D) in Cancer

Cancers ◽

10.3390/cancers12071755 ◽

2020 ◽

Vol 12 (7) ◽

pp. 1755 ◽

Cited By ~ 2

Author(s):

Casey W. Buller ◽

Porunelloor A. Mathew ◽

Stephen O. Mathew

Keyword(s):

Nk Cells ◽

Cancer Cells ◽

Nk Cell ◽

Therapeutic Option ◽

Effector Function ◽

Great Promise ◽

Cell Cytotoxicity ◽

Cell Receptors ◽

Nk Cell Receptors ◽

Nk Cell Cytotoxicity

Natural killer (NK) cells play a pivotal role in the immune system, especially in the recognition and clearance of cancer cells and infected cells. Their effector function is controlled by a delicate balance between the activating and inhibitory signals. We have identified 2B4 (CD244, SLAMF4) and CS1 (CD319, SLAMF7) as NK cell receptors regulating NK cell cytotoxicity. Lectin-like transcript 1 (LLT1), a member of the C-type lectin-like domain family 2 (CLEC2D), induced IFN-γ production but did not directly regulate cytolytic activity. Interestingly, LLT1 expressed on other cells acts as a ligand for an NK cell inhibitory receptor NKRP1A (CD161) and inhibits NK cytolytic function. Extensive research has been done on novel therapies that target these receptors to increase the effector function of NK cells. The 2B4 receptor is involved in the rejection of melanoma cells in mice. Empliciti, an FDA-approved monoclonal antibody, explicitly targets the CS1 receptor and enhances the NK cell cytotoxicity against multiple myeloma cells. Our studies revealed that LLT1 is expressed on prostate cancer and triple-negative breast cancer cells and allows them to evade NK-cell-mediated killing. In this review, we describe NK cell receptors 2B4, CS1, and LLT1 and their potential in targeting cancer cells for NK-cell-mediated immunotherapy. New cancer immunotherapies like chimeric antigen receptor T (CAR-T) and NK (CAR-NK) cells are showing great promise in the treatment of cancer, and CAR cells specific to these receptors would be an attractive therapeutic option.

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Applying CRISPR-based genetic screens to identify drivers of tumor-cell sensitivity towards NK-cell attack

10.1101/531962 ◽

2019 ◽

Cited By ~ 1

Author(s):

Klara Klein ◽

Tim Wang ◽

Eric S. Lander ◽

Marcus Altfeld ◽

Wilfredo F. Garcia-Beltran

Keyword(s):

Tumor Cell ◽

Nk Cells ◽

Tumor Cells ◽

Cell Function ◽

Nk Cell ◽

Target Cells ◽

Cell Cytotoxicity ◽

Genetic Screens ◽

A Genome ◽

Nk Cell Cytotoxicity

ABSTRACTNatural killer (NK) cells distinguish cancer cells from healthy cells using an array of germline-encoded receptors that interact with ligands expressed on target cells. A balance of inhibitory and activating signals transduced by these receptors regulate NK cell function to provide anti-tumor immunity while maintaining self-tolerance. However, knowledge of the spectrum of factors regulating NK-cell-mediated cytotoxicity, including the contribution of specific ligands and regulatory mechanisms for their expression on tumor cells, remains incomplete. Here, we apply a genome-wide loss-of-function screen in tumor cells using CRISPR/Cas9 technology to identify the factors that promote NK-cell cytotoxicity towards tumor cells. We established the drivers of tumor-cell sensitivity towards NK-cell attack (TuSeNKA) screening approach using the chronic myeloid leukemia (CML) cell line, K562. Interestingly, we identified B7H6, the ligand for the activating NK cell receptor NKp30, as the single factor whose loss resulted in increased resistance of K562 cells towards NK cells. Our study shows that combination of CRISPR-based genetic screens with NK-cell cytotoxicity assays is a valuable tool for identifying functionally relevant NK cell-tumor cell interactions, paving the way for further investigations that unravel the complexity of signals that promote NK-cell recognition of transformed cells and develop therapies that target these modes of tumor-cell killing.

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Introduction of Differential KIR Activation Mediated Patters of NK Cell Cytotoxicity Against Myeloma

Blood ◽

10.1182/blood.v116.21.5178.5178 ◽

2010 ◽

Vol 116 (21) ◽

pp. 5178-5178 ◽

Cited By ~ 1

Author(s):

Thomas StÜbig ◽

York Hildebrand ◽

Karla Jungk ◽

Aga Konielsk ◽

Lars Lange ◽

...

Keyword(s):

Nk Cells ◽

Cell Line ◽

Cell Lines ◽

Target Cell ◽

Nk Cell ◽

Myeloma Cell ◽

Cell Cytotoxicity ◽

Myeloma Cell Line ◽

Kir Receptors ◽

Nk Cell Cytotoxicity

Abstract Abstract 5178 Background: Natural Killer cells (NK cells) are part of the innate immune system. These cells have the ability to recognise and kill malignant cells, like myeloma cells. NK cell activation is tightly regulated by different activating or inhibiting receptors. Killer immunoglobulin like receptors (KIR, CD158) are a family of receptors which have activating as well as inhibitory function. KIR molecules are thought to recognize the HLA-C molecules, which then lead to NK cell signal transduction. Our knowledge about KIR expression and impact on tumor cell control has developed over the last years, but still our understanding of how the receptors are activated in multiple myeloma is limited. We therefore, investigated three different model systems for NK cell alloreactivity: 1) HLA-C/ HLA-C interaction model (KIR-Ligand model), 2) HLA-C/ KIR receptor interaction model, and 3) impact of donor KIR haplotype. Material and Methods: Three different myeloma cell lines (KMS12BM [C1/C1], MOLP8 [C1/C2] and RPMI8266 [C2/C1]) and a NK cell line (NKL) were cultured under standard conditions. NKL cells were transfected with human KIR2DL1 and KIR2DL3 alleles, respectively. For RNAi experiments two siRNA and two control siRNA were used. NK cells from healthy donors were isolated by magnetic end labeling. Enriched NK cells were HLA-typed for expression of HLA-C molecules, KIR receptor expression or KIR haplotype. Thereafter, NK cells were transiently transfected with the siRNA or control siRNA against the KIR2DL1 or KIR2DL3 receptors for up to 48 h. Functional analysis of the NK cell cytotoxicity was measured using a LDH release assay, based on their killing ability against the three fore mentioned myeloma cell lines. Results: Using NK cells that have been HLA-C genotyped as HLA-C1/C1, we observed a rescue of C1/C1 positive meyeloma cell lines in contrast to the C2/C1 myeloma cell line (12% cytotoxicity vs. 38% and 45% cytotoxicity, respectively, p <0.05). KIR receptors, by recognition of HLA-C molecules, are believed to reduce NK cell cytotoxicity. We used NK cells from healthy donors, which express KIR2DL1 (recognizing C2) to evaluate whether receptors` RNAi knockdown could increase the ability of NK cells to lyse target cells. Knockdown of KIR2DL1 in NK cells results in a highly efficient killing of a C2/C2 target cell line (RNAi treated NK cells showed a cytotoxicity up to 70%, p<0.05). To evaluate whether KIR receptors are major inhibitory molecules, we used the NK cell line (wt NKL, a non expressor of KIR receptors) that exhibited high cytotoxic potential against all tested target cell lines (>65% cytotoxicity). This NK cell line was transfected with KIR2DL1 or KIR2DL3 (recognizing C2, or C1). C2 positive myeloma cell lines were significantly rescued when exposed to KIR2DL1 transfected NK cells (wt NKL 72% vs. KIR2DL1 NKL 29%, p <0.05). Similar results were obtained when C1 positive target cell line was co- cultured with KIR2DL3 transfected NK cells. RNAi mediated silencing of KIR overexpression restores protection observed. As last model for the regulation of NK cell cytotoxicity we used KIR haplotyped NK cells and co-cultured them with a C1/C2 myeloma cell line. NK cells with an AA KIR haplotype showed the lowest killing capacity against the myeloma cell line, while BB KIR haplotype had higher killing potential. (46% vs 59%, p=0,005). Conclusions: We have shown that NK cell cytotoxicity is regulated by the HLA-C expression on the target cell as well as the expression of a specific KIR receptor and various KIR haplotypes. All tested models showed significant killing effect on myeloma cells. These data underline the importance of KIR receptor modulation on NK cell alloreactivity against myeloma cells. Disclosures: No relevant conflicts of interest to declare.

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Interdependence of CTL and NK cell cytotoxicity against melanoma cells

10.1101/2020.06.14.150672 ◽

2020 ◽

Author(s):

Kim S. Friedmann ◽

Arne Knörck ◽

Sabrina Cappello ◽

Cora Hoxha ◽

Gertrud Schwär ◽

...

Keyword(s):

Nk Cells ◽

Cancer Cells ◽

Induced Resistance ◽

Nk Cell ◽

Antigen Expression ◽

Melanoma Cells ◽

Human Model ◽

List Type ◽

Cell Cytotoxicity ◽

Nk Cell Cytotoxicity

AbstractCTL and NK cells recognize and eliminate cancer cells. However, immune evasion, down regulation of immune function by the tumor microenvironment, or resistance of cancer cells are a major problem. While CTL and NK cells are both important to eliminate cancer, most studies address them individually. In a new experimental human model, we analysed combined primary human CTL and NK cell cytotoxicity against the melanoma cell line SK-Mel-5. At high effector-to-target ratios, MART-1-specific CTL or NK cells eliminated SK-Mel-5 cells within 24 hours indicating that SK-Mel-5 cells are initially not resistant. However, at lower effector-to-target ratios, which resemble conditions of the immune contexture in human cancer, a significant number of SK-Mel-5 cells survived. Whereas CTL pre-exposure induced resistance in surviving SK-Mel-5 cells to subsequent CTL or NK cell cytotoxicity, NK cell pre-exposure induced resistance in surviving SK-Mel-5 cells to NK cells but not to MART-1 specific CTL. In contrast, there was even a slight enhancement of CTL cytotoxicity against SK-Mel-5 cells following NK cell pre-exposure. In all other combinations, resistance to subsequent cytotoxicity was higher, if melanoma cells were pre-exposed to larger numbers of CTL or NK cells. Increases in human leukocyte antigen class I expression correlated with resistance to NK cells, while reduction in MART-1 antigen expression correlated with reduced CTL cytotoxicity. CTL cytotoxicity was rescued beyond control levels by exogenous MART-1 antigen. This study quantifies the interdependence of CTL and NK cell cytotoxicity and may guide strategies for efficient CTL-NK cell anti-melanoma therapies.Key points summaryCytotoxic T lymphocytes (CTL) and natural killer (NK) cells eliminate cancer cells. CTL and NK work in parallel, but most studies address them individually.In a new human experimental model, antigen-specific CTL and NK cell cytotoxicity interdependence against melanoma is shown.Whereas high numbers of antigen-specific CTL and NK cells eliminate all melanoma cells, lower, more physiological numbers induce resistance, in case secondary CTL or NK cell exposure follow initial CTL cell exposure or if secondary NK cell exposure follows initial NK cell exposure; only if secondary CTL exposure follows initial NK cell exposure no resistance of melanoma but even a slight enhancement of cytotoxicity was observed.Alterations in HLA-I expression correlated with resistance to NK cells, while reduction in antigen expression correlated with reduced CTL cytotoxicity. CTL cytotoxicity was rescued beyond control levels by exogenous antigen.The results should help to better understand and optimize immune therapies against cancer.Graphical abstract

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