scholarly journals Evaluation of Interaction Between NK Cells and Colorectal Carcinoma Cells for Development of NK Cell-Based Immunotherapy in Patients with Refractory Disease

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 5810-5810
Author(s):  
Elisabetta Todisco ◽  
Ilaria Turin ◽  
Federica Ferulli ◽  
Matteo Tanzi ◽  
Silvia Brugnatelli ◽  
...  

Abstract Background The failure of conventional treatment and target therapies to significantly improve outcomes in metastatic colorectal cancer (mCRC) has prompted the development of immune-based therapies, including natural killer (NK) cells-based strategies. NK cells can kill target cells directly, as well as mediate antibody (Ab)-dependent cellular cytotoxicity (ADCC) via the membrane receptor FcgRIII, which binds to the Fc portion of IgG Ab. This feature makes them of particular importance in the immunotherapy of mCRC patients harboring the KRAS mutation that cannot benefit from administration of anti-epidermal growth factor receptor (EGFR) drugs. In this study we evaluated the capacity of patients derived NK cells, either resting or after cytokine activation, to lyse autologous mCRC cells. mCRC cells were analyzed for expression of ligands for adhesion and triggering NK receptors involved in their recognition and killing. We also evaluated whether KRAS mutated mCRC cells were susceptible to anti-EGFR-induced ADCC mediated by NK cells. Patients and methods. After obtaining informed signed consent, 25 mCRC patients have been enrolled to date. Tumor cells were disaggregated by GentleMACS Dissociator (Miltenyi Biotec,Germany), in vitro expanded and analyzed for the expression of ligands for NK triggering receptors. Ligands expression was evaluated by cytofluorimetric analysis and gene expression by qPCR on mCRC cultured cells and by immunohistochemistry in sections of samples embedded in paraffin. Resting and IL-2- or IL-15-activated NK cells, were analyzed for expression of triggering and inhibitory receptors and for their ability to kill autologous mCRC cells alone or after incubation with anti-EGFR monoclonal antibodies (mAbs) in a 51Cr release cytotoxicity assay. Results. Tumor cells were successfully expanded from 21 of 25 samples. Experiments performed in 10 patients showed the inability of patients resting NK cells to lyse mCRC cells (< 10% at effector:target ratio (E:T) of 20:1. Cytokine overnight (ON) activation resulted in an increased NK cytotoxic activity (IL-2: mean 28%; range:10-71; and IL-15: mean 40%; range 16-76 at E:T ratio of 20:1). Additional days of NK cell activation were able to further enhance their lytic capability. In resting NK cells the mean surface expression of activating receptors DNAM-1 and NKG2D was 79%, (range 75-91) and 39 % (range 29-58), respectively. The latter was up-regulated by ON cytokine activation (IL-2: mean 53%, range 48-70; IL-15: mean 70%, range 63-87). Among activating natural cytotoxicity receptors (NCRs), NKp46 is highly expressed both on resting and activated cells (>90%), while low surface expression of NKp30 and NKp44 was documented on resting NK cells (<10%). Their expression could be slightly up-regulated in particular after IL-15 ON activation (mean: 13%, range 9-30). Molecular analysis demonstrated a sizeable gene expression of NK ligands PVR, Nectin-2 and MICA/B on mCRC cells. Cytofluorimetric analysis showed that PVR and Nectin-2 are expressed in a vast majority of cultured mCRC cells (mean 65%, range 60-76; and mean 78%, range 70-98), respectively, while MICA/B were less expressed (mean 18%, range 15-25). The incubation of mCRC cells with anti-EGFR mAbs increased their susceptibility to NK-mediated lysis irrespective of KRAS status of tumor cells. The average rate of increase was greater using resting NK cells as effectors. The ongoing experiments comparing mCRC ligands expression evaluated on cultured tumor cells versus paraffin embedded sections will clarify whether results obtained in vitrocould be translated to the clinical setting. Conclusions. The evidence that ex vivo activated autologous NK cells are able to lyse patients tumor cells can offer new therapeutic options to a cohort of mCRC patients with a poor prognosis. Disclosures No relevant conflicts of interest to declare.

Blood ◽  
2010 ◽  
Vol 116 (21) ◽  
pp. 3193-3193 ◽  
Author(s):  
Theresa Placke ◽  
Lothar Kanz ◽  
Helmut R. Salih ◽  
Hans-Georg Kopp

Abstract Abstract 3193 NK cells as part of the innate immune system substantially contribute to cancer immune surveillance. They prevent tumor progression and metastasis due to their ability to mediate cellular cytotoxicity and to produce cytokines like IFN-γ, which, among others, stimulates subsequent adaptive immune responses. NK reactivity results from an integrative response emerging upon recognition of multiple ligands for activating and inhibitory NK cell receptors including various members of the TNFR family. Apart from the direct interaction with their target cells, NK cell activity is further influenced by the reciprocal interplay with various other hematopoietic cells like e.g. dendritic cells. Metastatic tumor spread in experimental animals is dramatically reduced in thrombopenic mice. Additional depletion of NK cells reverses this effect, indicating that platelets may impair NK anti-tumor reactivity. However, the underlying mechanisms have not been fully elucidated, especially in humans. Recently, we demonstrated that NK anti-tumor immunity is impaired by platelet-derived TGF-β, which is released upon interaction of platelets with tumor cells (Kopp et al., Cancer Res. 2009). Here we report that the ligand for the TNFR family member GITR (GITRL) is upregulated on megakaryocytes during maturation resulting in substantial GITRL expression by platelets. Since we recently identified GITR as inhibitory NK receptor involved in tumor immune escape (e.g., Baltz et al., Blood 2008, Baessler et al., Cancer Res. 2009) we investigated how platelet-derived GITRL influences platelet function and NK immune surveillance. Signaling via GITRL into platelets upon interaction with NK-expressed GITR or recombinant GITR-Ig fusion protein did not alter platelet activation as revealed by analysis of the activation marker CD62P and release of TGF-β. Interestingly, we found that GITRL-negative tumor cells rapidly get coated by platelets, which confers a seemingly GITRL-positive phenotype. “GITRL pseudoexpression” on tumor cells caused a substantial reduction of NK cell cytotoxicity and cytokine production. This reduced NK reactivity was not due to induction of apoptosis via GITR and could be restored by addition of a blocking GITR antibody. Thus, coating of tumor cells by platelets inhibits NK reactivity, which is in part mediated by platelet-derived GITRL. Our data provide a functional basis for the previously observed finding that platelets increase metastasis i.e. by enabling evasion of tumor cells from NK-mediated immune surveillance. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 4164-4164
Author(s):  
Stefanie Raab ◽  
Korbinian Nepomuk Kropp ◽  
Alexander Steinle ◽  
Gerd Klein ◽  
Lothar Kanz ◽  
...  

Abstract Introduction: NK cells are cytotoxic lymphocytes the reactivity of which is governed by the principles of ‘missing-self’ and “induced-self’ recognition. This implies that cells with low or absent expression of MHC class I and/or stress-induced expression of ligands for activating receptors like NKG2D (NKG2DL) are preferentially eliminated by NK cells. We and others reported previously that NKG2DL undergo proteolytic cleavage (i.e. shedding) which promotes evasion from NKG2D-mediated tumor immunosurveillance. Notably, the reactivity of NK cells is also influenced by various other components of the hematopoietic system, and we and others provided evidence for the involvement of platelets in tumor immune evasion including impairment of NKG2D-mediated immune surveillance (e.g., Kopp et al., Cancer Res 2009, Raab et al., Blood 2013 122:3488). Here we extend our recent findings and provide further data how platelets affect immunostimulatory NKG2D-NKG2DL interaction. Methods: Tumor cells were incubated with platelets from healthy donors or treated with platelet-derived soluble factors (releasate) obtained by stimulation of platelets with known platelet agonists including ADP and thrombin. NKG2DL and ADAM10 as well as ADAM17 surface expression on tumor cells and platelets, respectively, was measured by FACS, while release of NKG2DL was determined by ELISA. ADAM10 and 17 protein levels were assessed by immunoblotting. NK cell lysis of tumor cells in the presence or absence of coating platelets or platelet releasate was determined by chromium release assays. Results: We found that interaction of platelets with tumor cells resulted in substantially reduced NKG2DL expression on the surface of the malignant cells, which was paralleled by enhanced release of soluble NKG2DL. Similar albeit weaker effects were observed upon treatment of tumor cells with platelet releasate, indicating that platelet-derived factors mediate NKG2DL shedding from the tumor cell surface. Notably, ADAM10 and ADAM17, the known sheddases of NKG2DL, were found to be expressed on the platelet surface, and sheddases could also be detected in platelet releasate, pointing to an involvement in platelet-mediated NKG2DL shedding. Diminished NKG2DL surface expression resulted in reduced NKG2D-mediated NK cell cytotoxicity as revealed by blocking experiments using NKG2D antibody and F(ab)2 fragments specific for the modulated NKG2DL. Conclusion: We propose that induction of NKG2DL shedding constitutes a novel mechanism by which the interaction of platelets with metastasizing tumor cells impairs NK cell immunosurveillance. Disclosures No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 18-18
Author(s):  
Kyohei Nakamura ◽  
Masafumi Nakayama ◽  
Mitsuko Kawano ◽  
Tomonori Ishii ◽  
Hideo Harigae ◽  
...  

Abstract Introduction The activating receptor, NKG2D, plays crucial role in natural killer (NK) cell-mediated effector function. NKG2D is involved not only in host defense against tumor and viral infection, but also in autoimmune diseases by recognizing stress-induced self-ligands (NKG2DLs). However, the negative feedback regulation of NKG2D has not been fully understood. It has been reported that NK cells undergo rapid apoptosis upon interaction with NK-sensitive tumor cells, suggesting that activation-induced NK cell death can be triggered in certain situations. In this study, we aimed to elucidate underlying mechanism of NK cell death, especially focused on NKG2D-NKG2DLs interaction. Methods NK cells were purified from splenocytes of C57BL/6, perforin-/-, and DAP10-/-/12-/- mice, and cultured with rhIL-2 (1000 U/ml) for 5 days. We used these IL-2-activated NK cells as effector cells and three target cell lines: mouse T cell lymphoma RMA cells (RMA), RMA lacking MHCI expression (RMA-S), and RMA stably expressing an NKG2DL, Rae-1δ (RMA/Rae-1δ). CFSE-labeled NK cells were co-cultured with target cells for 2 hours, and stained with anti-NK1.1 mAb propidium iodide (PI). The percentage of PI-positive cells within CFSE+ NK1.1+ population was measured by flowcytometry. The cell surface expression of Rae-1 on NK cells after co-culture with target cells was evaluated by flowcytometry and confocal microscopy. Results NK cells from WT mice rapidly underwent cell death when co-cultured with Rae-1δ, but not with RMA or RMA-S, suggesting that NKG2D-Rae-1 interaction is involved in NK cell death. NK cells from perforin-/-, and DAP10-/-/12-/- mice did not undergo cell death, highlighting the importance of the NKG2D pathway for NK cell death. However, cross-linking of NKG2D receptor failed to induce NK cell death. To understand underlying the mechanism of NK cell death, we evaluated the cell surface expression of NKG2DLs on NK cells after co-culture with tumor cells. We found that cell surface expression of Rae-1 on NK cells was remarkably induced after co-culture with RMA/Rae-1δ, but no with RMA or RMA-S, implying that these Rae-1-positive NK cells may be lysed by NK cells through NKG2D-induced perforin pathway. The cell surface induction of Rae-1 on NK cells was very rapid (within 5min), and it occurred cell-cell contact dependent manner. Interestingly, NK cells from C57/BL6 mice rapidly became BALB/c allele Rae-1γ-positive after co-culture with RMA/Rae-1γ, indicating that NK cells acquire tumor-derived Rae-1. Consistently, acquisition of Rae-1 by NK cells was confirmed by confocal microscopy. Therefore, NK cells rapidly dress tumor-derived Rae-1 after interaction with tumor cells through intercellular membrane transfer, namely trogocytosis. Trogocytosis of Rae-1 was significantly inhibited in NK cells from DAP10-/-/12-/- mice and by chemical inhibitors of PI3K and Syk, indicating that it requires NKG2D-signaling. To confirm whether Rae-1-dressed NK cells can be recognized and lysed by other NK cells, we used sort-purified Rae-1-dressed NK cells as target cells. Rae-1-dressed NK cells were lysed by WT NK cell in an E/T-ratio dependent manner through NKG2D-induced perforin pathway. Furthermore, adoptively transferred Rae-1-dressed NK cells were significantly eliminated in Rag-1-deficient mice, indicating that Rae-1-dressed NK cells are also recognized and lysed in vivo. Conclusion Upon interaction with NKG2DLs-expressing tumor cells NK cells rapidly dress tumor-derived NKG2DLs, and subsequently undergo fratricide. Our results provide novel insights into activation-induced NK cell death via dynamic intercellular communications. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 3488-3488
Author(s):  
Stefanie Raab ◽  
Korbinian Nepomuk Kropp ◽  
Alexander Steinle ◽  
Lothar Kanz ◽  
Hans-Georg Kopp ◽  
...  

Abstract NK cells play an important role in the immunosurveillance of tumor cells. The mechanisms leading to NK cell activation are described by the ‘missing-self’ and “induced-self’ hypotheses, implying that cells with low or absent expression of MHC class I and stress-induced expression of ligands for activating receptors like e.g. NKG2D (NKG2DL) are preferentially recognized and eliminated by NK cells. Besides the direct interaction with their target cells, NK activity is further influenced by various other hematopoietic cells. In mouse models, thrombocytopenia impairs metastasis, and this is reversed by additional depletion of NK cells. However, the knowledge regarding the molecular mechanisms by which platelets influence NK cells is still fragmentary. We recently reported that release of TGF-β by platelets upon their interaction with (metastasizing) tumor cells downmodulates NKG2D on NK cells (Kopp et al., Cancer Res. 2009; Placke et al., J Innate Immun. 2011). Moreover, platelets transfer “healthy” MHC class I to the tumor cell surface. Thus, platelets may facilitate metastasis by interfering with both, “induced and missing self’ NK cell recognition. Here we provide evidence for a yet unknown mechanism by which platelets further impair NKG2D-mediated immunosurveillance. Tumor cells were incubated with platelets from healthy donors resulting in coating of tumor cells and activation of the platelets, or treated with platelet-derived soluble factors (releasate) obtained either by tumor cell-induced platelet activation (TCIPA) or the platelet agonist thrombin. Presence of platelet derived factors derived either from coating of tumor cells or contained in platelet releasate substantially reduced NKG2DL surface expression on tumor cells. This was paralleled by enhanced levels of soluble NKG2DL in culture supernatants, indicating that platelet-derived factors mediate NKG2DL shedding from the tumor cell surface. Diminished NKG2DL surface expression resulted in decreased NKG2D-dependent cytotoxicity of NK cells as revealed by blocking experiments using NKG2D antibody and NKG2DL-specific F(ab)2 fragments targeting the specific modulated NKG2DL. Our data thus identify induction of NKG2DL shedding as novel mechanism by which interaction of platelets with metastasizing tumor cells impairs NK cell immunosurveillance. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 2993-2993
Author(s):  
Theresa Placke ◽  
Hans-Georg Kopp ◽  
Lothar Kanz ◽  
Helmut R Salih

Abstract Abstract 2993 Poster Board II-970 NK cells play an important role in cancer immunosurveillance and may prevent tumor progression and metastasis due to their ability to mediate direct cellular cytotoxicity and by releasing immunoregulatory cytokines which shape adaptive immune responses. Their reactivity is governed by various activating and inhibitory molecules expressed on target cells and reciprocal interactions with other hematopoietic cells like dendritic cells. Platelets contribute to tumor immune escape, metastasis, and angiogenesis (e.g. Jin et al Nature Med. 2006). In mice, thrombocytopenia inhibits metastasis, and this is reversed by NK cell depletion suggesting that platelets are an important additional player in NK cell-tumor interaction. However, the knowledge regarding the molecular mechanisms by which platelets influence NK cells is fragmentary at best. We found recently that platelet release soluble factors, most notably TGF-β, upon interaction with tumor cells which mediates NK cell silencing through downregulation of the activating immunoreceptor NKG2D (Kopp et al., Cancer Res 2009, in press). However, immunoregulatory molecules residing in the platelet membrane may also modulate NK cell anti-tumor responses. We report here that presence of platelets causes coating of tumor cells, and this markedly reduces NK cell lysis of tumor cells. This is mediated by conferment of “pseudoexpression” of platelet-expressed immunoregulatory molecules to tumor cells which are absent on the tumor cells alone. Among those immunregulatory molecules we identified various ligands for NK cell receptors like MHC class I, GITR ligand or CD62P. To establish the functional significance of tumor cell pseudoexpression of platelet molecules we employed functional analyses of tumor cells and NK cells with or without coating by autologous platelets. The impaired anti-tumor reactivity of NK cells against coated tumor cells was restored by blocking MHC class I on the coating platelets, while isotype control had no effect. Moreover, coating of tumor cells by platelets was validated by ex vivo analyses of primary leukemic cells from patients which also revealed substantial coating by platelets and confered expression of NK cell-modulating molecules. Our data indicate that platelets enable a molecular mimicry of tumor cells, which enables tumor cells to escape NK cell-mediated tumor immunosurveillance. Disclosures: No relevant conflicts of interest to declare.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A938-A938
Author(s):  
Chiara Zambarda ◽  
Karolin Guldevall ◽  
Chiara Zambarda ◽  
Karolin Guldevall ◽  
Christian Breunig ◽  
...  

BackgroundThe use of bispecific natural killer (NK) cell engagers has emerged as a successful strategy for immune cell activation and killing of tumor cells through antibody-dependent cellular cytotoxicity (ADCC). Among these, tetravalent, bispecific innate cell engagers (ICE®) with specificity for the activating receptor CD16A selectively triggering innate responses from NK cells or macrophages represent the most clinically advanced concept. The CD30/CD16A specific ICE® AFM13, has shown efficacy in patients with CD30+ lymphomas as monotherapy1 and combination therapy with check-point inhibitors2 and most recently in combination with adoptive NK cell therapy.3 The EGFR/CD16A specific ICE® AFM24, targeting a variety of solid tumors like colorectal, or lung cancer with a unique mode of action independent of EGFR signaling inhibition, is currently evaluated in an ongoing Ph1/2a clinical study.MethodsWe used a microchip-based screening with single cell resolution4 to elucidate the dynamic responses of individual NK cells towards tumor target cells upon treatment with AFM13 or AFM24.ResultsWe found that AFM13 and AFM24 mediated potent activation of NK cells, leading to increased responsive cytotoxic NK cells and significantly increased the number of NK cells that exerted engagement with multiple target cells rendering these NK cells serial killers. Strikingly, bispecific ICE® molecules triggered stronger cytotoxic responses compared to monoclonal antibodies. One suggested strategy to boost killing by NK cells is to use molecular inhibitors or protein constructs that prevent shedding of CD16.5 However, previous results have shown that this can lead to impaired detachment from target cells, reducing the capacity for an individual NK cell to form serial contacts to target cells.6 We observed that the elevated NK cell killing induced by ICE® molecules was largely conserved when cells were treated with the shedding inhibitor Batimastat. Analysis of the functional dynamics of NK cells revealed that inhibition of CD16 shedding prevented NK cell detachment from target cells, resulting in cell cluster formation. This might strongly impact targeting of distant tumor cells by an individual NK cell thus limiting its anti-tumoral activity.ConclusionsIn conclusion, we show that both AFM13 and AFM24 increase the fraction of tumor-target responsive NK cells and boost serial killing of target cells by individual NK cells. Based on these data, ICE® molecules can be characterized as potent anti-tumoral agents leveraging the enormous potential of NK cells while maintaining crucial features of NK cell biology.AcknowledgementsWe thank members of the Önfelt lab for their valuable help and feedback.ReferencesSawas A, Elgedawe H, Vlad G, Lipschitz M, Chen P-H, Rodig SJ, et al. Clinical and biological evaluation of the novel CD30/CD16A tetravalent bispecific antibody (AFM13) in relapsed or refractory CD30-positive lymphoma with cutaneous presentation: a biomarker phase Ib/IIa study (NCT03192202). Blood 2018;132(Supplement 1):2908–2908.Bartlett NL, Herrera AF, Domingo-Domenech E, Mehta A, Forero-Torres A, Garcia-Sanz R, et al. A phase 1b study of AFM13 in combination with pembrolizumab in patients with relapsed or refractory Hodgkin lymphoma. Blood 2020. Blood 2020;136(21):2401–2409.Kerbauy LN, Marin ND, Kaplan M, Banerjee PP, Berrien-Elliott MM, Becker-Hapak M, et al. Combining AFM13, a bispecific CD30/CD16 antibody, with cytokine-activated blood and cord blood–derived NK cells facilitates CAR-like responses against CD30 + malignancies. Clin Cancer Res Epub 2021.Guldevall K, Brandt L, Forslund E, Olofsson K, Frisk TW, Olofsson PE, et al. Microchip screening platform for single cell assessment of NK cell cytotoxicity. Front Immunol 2016;7:119.Romee R, Foley B, Lenvik T, Wang Y, Zhang B, Ankarlo D, et al. NK cell CD16 surface expression and function is regulated by a disintegrin and metalloprotease-17 (ADAM17). Blood 2013;121(18):3599–608.Srpan K, Ambrose A, Karampatzakis A, Saeed M, Cartwright ANR, Guldevall K, et al. Shedding of CD16 disassembles the NK cell immune synapse and boosts serial engagement of target cells. J Cell Biol 2018;217(9):3267–83.Ethics ApprovalThis work was performed with NK cells from healthy anonymous blood donors, which requires no ethical permit according to local regulations.


Blood ◽  
2007 ◽  
Vol 109 (9) ◽  
pp. 3767-3775 ◽  
Author(s):  
Laura Chiossone ◽  
Chiara Vitale ◽  
Francesca Cottalasso ◽  
Sara Moretti ◽  
Bruno Azzarone ◽  
...  

Abstract Steroids have been shown to inhibit the function of fresh or IL-2–activated natural killer (NK) cells. Since IL-15 plays a key role in NK-cell development and function, we comparatively analyzed the effects of methylprednisolone on IL-2– or IL-15–cultured NK cells. Methylprednisolone inhibited the surface expression of the major activating receptors NKp30 and NKp44 in both conditions, whereas NK-cell proliferation and survival were sharply impaired only in IL-2–cultured NK cells. Accordingly, methylprednisolone inhibited Tyr phosphorylation of STAT1, STAT3, and STAT5 in IL-2–cultured NK cells but only marginally in IL-15–cultured NK cells, whereas JAK3 was inhibited under both conditions. Also, the NK cytotoxicity was similarly impaired in IL-2– or IL-15–cultured NK cells. This effect strictly correlated with the inhibition of ERK1/2 Tyr phosphorylation, perforin release, and cytotoxicity in a redirected killing assay against the FcRγ+ P815 target cells upon cross-linking of NKp46, NKG2D, or 2B4 receptors. In contrast, in the case of CD16, inhibition of ERK1/2 Tyr phosphorylation, perforin release, and cytotoxicity were not impaired. Our study suggests a different ability of IL-15–cultured NK cells to survive to steroid treatment, thus offering interesting clues for a correct NK-cell cytokine conditioning in adoptive immunotherapy.


Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3870-3870 ◽  
Author(s):  
Don Benson ◽  
Courtney E Bakan ◽  
Shuhong Zhang ◽  
Lana Alghothani ◽  
Jing Liang ◽  
...  

Abstract Abstract 3870 Poster Board III-806 Background NK cell activity against tumor cells is regulated by a balance of inhibitory and activating signals mediated by receptors on NK cells that recognize inhibitory and activating ligands expressed by cancer cells. IPH2101 (1-7F9) is a novel monoclonal anti-inhibitor KIR blocking antibody that has been shown to augment NK cell function against MM targets. Moreover, lenalidomide has been shown to expand and activate NK cells in vivo and in vitro. We have previously reported that the combination of IPH2101 and lenalidomide enhances NK cell mediated cytotoxicity against MM cells compared to each agent alone (Zhang et al., AACR 2009). We expand our studies to investigate potential mechanisms for the enhancement of NK cell activity by the combination of IPH2101 and lenalidomide. Methods The effects of IPH2101 and lenalidomide alone and in combination were studied using primary human NK cells from healthy donors as well as from MM patients. The MM cell lines U266 and RPMI 8226 as well as primary tumor cells from marrow aspirates of MM patients served as target cells. The effect of lenalidomide on MM activating and inhibitory ligand expression was studied by flow cytometry. NK cell trafficking was investigated with standard transwell plate migration assay. Immune complex formation between NK cell effectors and MM tumor targets was characterized by flow cytometry in control conditions and with NK cells pre-treated with IPH2101 and lenalidomide. The effects of IPH2101 and lenalidomide were studied regarding interferon-gamma and granzyme B production by ELISPOT and target-specific cytotoxicity studies were conducted to complement effector-based assays. Results IPH2101 (30 ug/ml) significantly enhanced cytotoxicity against U266 cells and primary MM tumor cells by both purified NK cells at effector:target (E:T) ratios of 10:1 or less, and also of freshly isolated peripheral blood mononuclear cells (PBMC) at E:T ratios of 60:1 or less, from more than 10 random donors. In addition, treatment of PBMC with 5-10 μmol/L lenalidomide for 72h without interleukin (IL)-2 increased NK cell lysis of U266. Treatment of PBMC from normal donors did not enhance the expression of the NK receptors KIR, NKG2D, NCR, TRAIL, and DNAM-1. Incubation of U266 cells with lenalidomide (5 uM) for 3-5 days resulted in significant enhancement of cytotoxicity by normal donor NK cells. This was associated with upregulation of the activating ligands, MICA, ULBP-2, DR4, and CD112. Using blocking antibodies to NKG2D, TRAIL, and DNAM-1, lenalidomide enhancement of MM cell killing was abrogated indicating the importance of the modulation of the ligands to the latter receptors by lenalidomide. Although IPH2101 and lenalidomide did not significantly increase NK cell migration into normal media, migration was enhanced 2.98-fold (+/− 0.36, p < 0.05) towards U266 cell targets (n= 3, p < 0.05) and MM patient serum 3.2-fold (+/− 0.4, n=3, p < 0.05). IPH2101 and lenalidomide also led to a 2.3-fold (+/− 0.43, p < 0.05) increase in immune complex formation between NK cells and MM tumor cells. IPH2101 and lenalidomide also augmented NK cell interferon gamma production against MM (control mean 303 spots/well +/− 13 versus 525 +/− 83, n=3, p < 0.05) and granzyme B production (control mean 115 +/− 98 versus 449 +/−72, n=3, p < 0.05). Importantly, in all experiments described herein, the effects of IPH2101 and lenalidomide together were greater than either agent alone. Conclusions Taken together, our data suggest that IPH2101 and lenalidomide may exert complementary mechanisms on both effector and target cells to enhance NK cell mediated killing of MM cells. Moreover, these agents have no predicted clinical cross-toxicities. A single-agent phase 1 clinical trial of IPH2101 has shown the mAb to be safe and well tolerated in MM patients. These findings support a phase 1/2 clinical trial of IPH2101 with lenalidomide as a first dual-innate immunotherapy for patients with MM. Disclosures: Andre: Innate Pharma: Employment. Squiban:Innate pharma: Employment. Romagne:Innate Pharma: Employment.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 1537-1537 ◽  
Author(s):  
Julia Hilpert ◽  
Katrin Baltz-Ghahremanpour ◽  
Benjamin J Schmiedel ◽  
Lothar Kanz ◽  
Gundram Jung ◽  
...  

Abstract Abstract 1537 The capability of anti-tumor antibodies to recruit Fc-receptor (FcR) bearing effector cells like NK cells, a feature considered critical for therapeutic success, can be markedly improved by modifications of the human IgG1 part. At present, Fc-engineered antibodies targeting leukemia cells are yet not available. The various ligands of the NK cell-activating immunoreceptor NKG2D (NKG2DL) are generally absent on healthy cells but upregulated on malignant cells of various origins including leukemia. We aimed to take advantage of the tumor-restricted expression of NKG2DL by using them as target-antigens for Fc-optimized NKG2D-IgG1 fusion proteins targeting leukemia cells for antibody-dependent cellular cytotoxicity (ADCC) and IFN-g production of NK cells. NKG2D-IgG1 fusion proteins with distinct modifications in their Fc portion were generated as previously described (Lazar 2006; Armour 1999). Compared to wildtype NKG2D-Fc (NKG2D-Fc-WT), the mutants (S239D/I332E and E233P/L234V/L235A/DG236/A327G/A330S) displayed highly enhanced (NKG2D-Fc-ADCC) and abrogated (NKG2D-Fc-KO) affinity to the NK cell FcgRIIIa receptor but comparable binding to NKG2DL-expressing target cells. Functional analyses with allogenic NK cells and leukemia cell lines as well as primary leukemic cells of AML and CLL patients revealed that NKG2D-Fc-KO significantly (p<0.05, Mann-Whitney U test) reduced NK cytotoxicity and IFN-g production (about 20% and 30% reduction, respectively), which can be attributed to blockade of NKG2DL-mediated activating signals. Treatment with NKG2D-Fc-WT significantly (p<0.05, Mann-Whitney U test) enhanced NK reactivity (about 20% and 100% increase in cytotoxicity and cytokine production, respectively). The effects observed upon treatment with NKG2D-Fc-ADCC by far exceeded that of NKG2D-Fc-WT resulting in at least doubled NK ADCC and IFN-g production compared to NKG2D-Fc-WT. When applied in combination with Rituximab in analyses with CLL cells, a clear additive effect resulting in a more than four-fold increase of ADCC and FcgRIIIa-induced IFN-g production was observed. The NKG2D-Fc fusion proteins did not induce NK reactivity against healthy blood cells, which is in line with the tumor-restricted expression of NKG2DL. Of note, treatment with NKG2D-Fc-ADCC also significantly (p<0.05, Mann-Whitney U test) enhanced reactivity (up to 70% increase) of NK cells against NKG2DL-positive AML and CLL cells among patient PBMC in an autologous setting. Together, our results demonstrate that Fc-engineered NKG2D-Fc-ADCC fusion proteins can effectively target NKG2DL-expressing leukemia cells for NK anti-tumor reactivity. In line with the hierarchically organized potential of the various activating receptors governing NK reactivity and due to their highly increased affinity to the FcgRIIIa receptor, NKG2D-Fc-ADCC potently enhances NK anti-leukemia reactivity despite the inevitable reduction of activating signals upon binding to NKG2DL. Due to the tumor-restricted expression of NKG2DL, Fc-modified NKG2D-Ig may thus constitute an attractive means for immunotherapy of leukemia. Disclosures: No relevant conflicts of interest to declare.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 245-245
Author(s):  
Benjamin J Schmiedel ◽  
Tina Baessler ◽  
Miyuki Azuma ◽  
Lothar Kanz ◽  
Helmut R. Salih

Abstract Abstract 245 The TNF family member RANKL and its receptors RANK and osteoprotegerin (OPG) are key regulators of bone remodelling, but have also been shown to influence progression of malignancies like breast cancer (Tan et al., Nature 2011), myeloma (Sordillo et al., Cancer 2003) and CLL (Secchiero et al. J Cell Physiol. 2006). NK cells are cytotoxic lymphocytes that play an important role in tumor immune surveillance especially of hematopoietic malignancies. Their reactivity is influenced by a variety of activating and inhibitory molecules expressed by their target cells including several members of the TNF family. Recently, we reported that RANK, upon interaction with RANKL which can be expressed by malignant hematopoietic cells, mediates signals that impair NK reactivity (Schmiedel et al., Blood 2010 116,21:893–893). Here we extended these analyses and comprehensively studied the expression and immunomodulatory function of RANKL in leukemia. Analysis of primary leukemia cells revealed substantial RANKL surface expression in a high proportion of the investigated cases (AML, 47 of 65 (72%); ALL, 16 of 21 (76%); CML, 6 of 10 (60%); CLL, all 54 (100%)). Signaling via surface-expressed RANKL into the malignant cells mediated the release of cytokines like TNF, IL-6, IL-8 and IL-10 which have been shown to act as autocrine and paracrine growth and survival factors in leukemia. Moreover, the factors released upon RANKL signaling upregulated RANK expression on NK cells. In line, NK cells from leukemia patients (n=75) displayed significantly (p<0.001, Mann-Whitney U-test) higher RANK expression compared to healthy controls (n=30) confirming our notion that RANK-RANKL interaction may contribute to leukemia pathophysiology. We further found that RANK-RANKL interaction, beyond directly inhibiting NK cell function via RANK, may contribute to evasion of leukemia cells from NK immunosurveillance by creating an NK inhibitory cytokine milieu. This was revealed by impaired cytotoxicity and degranulation in response to leukemia targets following exposure of the NK cells to the factors released upon RANKL signaling by leukemia cells. Notably, the RANKL-mediated cytokine release of leukemia cells could be disrupted by the clinically approved RANKL antibody Denosumab/AMG162. Thus, RANKL signaling may trigger a “vicious cycle” comprising of release of immunosuppressive cytokines and also upregulation of RANK on NK cells. The latter both directly inhibits NK reactivity and may result in augmented RANKL signaling into leukemia cells. Our data suggest that therapeutic modulation of the RANK/RANKL system e.g. with Denosumab/AMG162, which is approved for treatment of osteolysis, may be a promising strategy to reinforce NK reactivity against hematopoietic malignancies. Disclosures: No relevant conflicts of interest to declare.


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