scholarly journals Small Molecule Screening Identifies Rho-Associate Protein Kinase (ROCK) As a Regulator of NK Cell Cytotoxicity Against Cancer

Blood ◽  
2019 ◽  
Vol 134 (Supplement_1) ◽  
pp. 3607-3607
Author(s):  
Grace Lee ◽  
Sheela Karunanithi ◽  
Zachary Jackson ◽  
David Wald

NK cells are a subset of lymphocytes that directly recognize and lyse tumor cells without the limitation of antigen specific receptor recognition. In addition to behaving as cytotoxic effector cells, NK cells unlike T cells are not thought to elicit graft versus host disease. The combination of these characteristics makes NK cells a powerful tool for adoptive cell therapy. Despite the promise of NK cell therapy, key hurdles in achieving significant clinical efficacy include both generating sufficient numbers of highly tumoricidal NK cells and maintaining the cytotoxic activity of these cells in vivo despite the immunosuppressive tumor microenvironment. Our lab and others have developed several feeder cell line-based expansion modules that robustly stimulate the ex vivo proliferation of NK cells. However, strategies to enhance and sustain the activity of NK cells once administered in vivo are still limited. In order to identify strategies to enhance the cytotoxic activity of NK cells, we developed a high-throughput small molecule screen (Figure 1A) that involved a calcein-based cytotoxicity assay of ex vivo expanded and treated NK cells against ovarian cancer cells (OVCAR-3). 20,000 compounds were screened and the screen was found to be highly robust (Z'>0.59). We identified 29 hits that led to at least a 25% increase in cytotoxicity as compared to DMSO control-treated NK cells. One of the most promising hits was the pan-ROCK inhibitor, Y-27632 that led to an 30% increase in NK killing of the OVCAR-3 cells. We validated that ROCK inhibition leads to enhanced NK cell cytotoxic activity using Y-27632 (Figure 1B) as well as other well-established ROCK inhibitors such as Fasudil using a flow cytometry based killing assay. Y-27632 increased NK cell cytotoxicity in a dose- and time- dependent manner. ROCK inhibition consistently led to ~10-25% increase in NK cell cytotoxic activity directed against a variety of ovarian (Figure 1C) and other solid tumor cell lines (Figure 1D). Interestingly, we found that the NK hyperactivation persists for up to 48hrs after washing off the drug that may enable ex vivo stimulation before NK cell infusion. Our preliminary results showed that ROCK inhibition activates PI3K-dependent Akt activation (Figure 1E). We hypothesize that ROCK inhibition restores Akt activation which may be critical for NK cell activating receptor pathways and our current investigations will test these hypotheses. ROCK inhibitors, such as Y-27632 and Fasudil have been utilized in both preclinical and clinical studies for a variety of diseases such as atherosclerosis, neurodegenerative disorders, and ocular diseases. However, the consequences of ROCK inhibition in NK cells has not been thoroughly investigated. Our work shows a promising novel strategy to significantly enhance NK cell therapy against cancer that has high translational potential. Disclosures No relevant conflicts of interest to declare.

2017 ◽  
Vol 35 (7_suppl) ◽  
pp. 127-127
Author(s):  
Jeremiah Oyer ◽  
Sarah B. Gitto ◽  
Deborah Altomare ◽  
Dean A. Lee ◽  
Alicja Copik

127 Background: Ovarian cancer has high recurrence rate and could benefit from immunotherapy with NK cells. A necessity for NK cell therapy is an efficient way to generate high doses of NK cells. The best method currently used in clinical trials is ex vivo NK cell expansion by co-culture with K562 CML cells, modified to express 41-BBL and membrane bound IL21 (K562.mb21). However feeder cell based methods are limited to ex vivo co-culture, difficult to disseminate, and not allowed in many jurisdictions. To overcome these limitations and to further improve NK cell therapy, we developed a feeder cell free particle based method for NK cell stimulation. These particles (PM21) are nano-scale, made from cell membranes of K562.mb21 cells, and efficiently stimulate NK cell expansion (mean 825 fold in 14 days, range 163–2216, n = 13). Methods: PM21 particles were prepared from K562.mb21 cells with a procedure developed by our group. NK cells were expanded by culturing CD3 depleted PBMCs with PM21 particles or by co-culture with K562.mb21 cells for 14 days as previously described. NSG mice ( ≥ 8 per group) were implanted ip with 1 x 106 SKOV3 ovarian tumor cells, seeded 8 days, and then treated with vehicle or NK cells expanded with PM21 or K562.mb21 cells (two doses of 10 x 106, injected 6 days apart), with or without in vivo administration of PM21 particles (600 µg, 3x weekly), and IL2 (25 KU, 3x weekly), all delivered ip. Survival analysis was performed with log rank (Mantel-Cox) test. Results: Treatment of SKOV3 engrafted NSG mice with NK cells, expanded with K562.mb21 cells or with PM21 particles, allowed significant ( < 0.0001) 10 day increase in survival compared to untreated animals that succumbed on average 21 days after start of treatment. Administration of ip PM21 particles enhanced survival by 5 days (p = 0.056) over no in vivo PM21 groups. Conclusions: NK cells prepared with PM21 particles or with K562.mb21 cells are equivalent in anti-SKOV3 efficacy and in vivo application of PM21 particles provides further benefit. Clinical translation is underway and clinical trials are being planned. PM21 particles can be the next step in development of NK cell therapy for enhancing both efficacy and dissemination of NK cell therapeutics for ovarian cancer.


2021 ◽  
Vol 9 (Suppl 3) ◽  
pp. A834-A834
Author(s):  
Xue Yao ◽  
Sandro Matosevic

BackgroundThe effectiveness of natural killer (NK) cell-based immunotherapy against solid tumors is limited by the lack of specific antigens and the immunosuppressive tumor microenvironment (TME). Glioblastoma multiforme (GBM) is one such heavily immunosuppressive tumor that has been particularly hard to target and remains without a viable treatment. The development of novel approaches to enhance the efficacy of NK cells against GBM is urgently needed. NK cell engagers (NKCE) have been developed to enhance the efficacy of NK cell therapy.MethodsTo improve the clinical efficacy of NK cell therapy, we are developing a new generation of multi-specific killer engagers, which consists of a neoantigen-targeting moiety, together with cytokine and chemokine-producing domains. Neoantigens are new antigens formed specifically in tumor cells due to genome mutations, making them highly specific tools to target tumor cells. Our engager has been designed to target Wilms' tumor-1 (WT-1), a highly specific antigen overexpressed in GBM among other solid tumors. This is done through the generation of an scFv specific targeting the complex of WT-1126-134/HLA-A*02:01 on the surface of GBM. On the NK cell side, the engager is designed to target the activating receptor NKp46. Incorporation of the cytokine IL-15 within the engager supports the maturation, persistence, and expansion of NK cells in vivo while favoring their proliferation and survival in the tumor microenvironment. Additionally, our data indicated that the chemokine CXCL10 plays an important role in the infiltration of NK cells into GBM, however, GBM tumors produce low levels of this chemokine. Incorporation of a CXCL10-producing function into our engager supports intratumoral NK cell trafficking by promoting, through their synthetic production, increased levels of CXCL10 locally in the tumor microenvironment.ResultsCollectively, this has resulted in a novel multifunctional NK cell engager, combining neoantigen-cytokine-chemokine elements fused to an activating domain-specific to NK cells, and we have investigated its ability to support and enhance NK cell-mediated cytotoxicity against solid tumors in vitro and in vivo against patient-derived GBM models. The multi-specific engager shows both high tumor specificity, as well as the ability to overcome NK cell dysfunction encountered in the GBM TME.ConclusionsWe hypothesize that taking advantage of our multi-functional engager, NK cells will exhibit superior ex vivo expansion, infiltration, and antitumor activity in the treatment of GBM and other solid tumors.


Vaccines ◽  
2021 ◽  
Vol 9 (11) ◽  
pp. 1363
Author(s):  
Elena V. Abakushina ◽  
Liubov I. Popova ◽  
Andrey A. Zamyatnin ◽  
Jens Werner ◽  
Nikolay V. Mikhailovsky ◽  
...  

In the last decade, an impressive advance was achieved in adoptive cell therapy (ACT), which has improved therapeutic potential and significant value in promising cancer treatment for patients. The ACT is based on the cell transfer of dendritic cells (DCs) and/or immune effector cells. DCs are often used as vaccine carriers or antigen-presenting cells (APCs) to prime naive T cells ex vivo or in vivo. Cytotoxic T lymphocytes (CTLs) and natural killer (NK) cells are used as major tool effector cells for ACT. Despite the fact that NK cell immunotherapy is highly effective and promising against many cancer types, there are still some limitations, including insignificant infiltration, adverse conditions of the microenvironment, the immunosuppressive cellular populations, and the low cytotoxic activity in solid tumors. To overcome these difficulties, novel methods of NK cell isolation, expansion, and stimulation of cytotoxic activity should be designed. In this review, we discuss the basic characteristics of DC vaccines and NK cells as potential adoptive cell preparations in cancer therapy.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3666-3666
Author(s):  
Tarun K. Garg ◽  
Susann Szmania ◽  
Jumei Shi ◽  
Katie Stone ◽  
Amberly Moreno-Bost ◽  
...  

Abstract Immune-based therapies may improve outcome for multiple myeloma (MM) by eradicating chemo-resistant disease. Our recent trial utilizing IL2 activated, killer immunoglobulin-like receptor-ligand mismatched NK cell transfusions from haplo-identical donors yielded (n) CR in 50% of patients. Unfortunately, after NK cell therapy, 2/10 patients had progressive disease, and the median duration of response for the other 8/10 patients was only 105 days (range 58–593). This may have been due to an insufficient dose of alloreactive NK cells and early rejection. Furthermore, appropriate donors were identified for only 30% of otherwise eligible patients. We therefore investigated whether NK cells from MM patients could be expanded and activated to kill autologous MM. We then examined whether pre-treatment of MM cell targets with elotuzumab, a humanized antibody to the MM tumor antigen CS1, could further enhance NK cell-mediated lysis. PBMC from 5 MM patients were co-cultured for 14 days with irradiated K562 cells transfected with 4-1BBL and membrane bound IL15 in the presence of IL2 (300U/ml) as previously described (Imai et al, Blood2005;106:376–383). The degree of NK cell expansion, NK immunophenotype, and ability to kill MM (4 hour 51Cr release assays) were assessed. To determine the ability of ex vivo expanded NK cells to traffic to bone marrow, activated NK cells were injected into the tail vein of NK cell depleted NOD-SCID mice, which were then sacrificed after 48 hours. Flow cytometry for human CD45, CD3, and CD56 was performed on cells from blood, marrow and spleen. There was an average 64-fold expansion of NK cells (range: 8–200) after 2 weeks of co-culture with K562 transfectants. Expansion of T cells was not observed. The NK cell activating receptor NKG2D, and natural cytotoxicity receptors NKp30, NKp44, and NKp46 were up-regulated following the expansion. Expanded NK cells were able to kill autologous MM (E:T ratio 10:1, average 31%, range 22–41%), whereas resting NK cells did not. Pretreatment of autologous MM cells with elotuzumab increased the activated NK cell-mediated killing by 1.7-fold over target cells pretreated with an isotype control antibody. This level of killing was similar to that of the highly NK kill-sensitive cell line K562 (Figure). Autologous PHA blasts and CD34+ stem cells were not killed. Activated human NK cells were detectable in the bone marrow of NOD-SCID mice 48 hours after injection. Ex vivo activation of NK cells from MM patients with K562 transfectants can induce killing of autologous MM and produce large numbers of NK cells for potential therapy. The addition of elotuzumab to activated NK cell therapy enhances anti-MM effects by ADCC thus invoking an additional NK cell-mediated mechanism of MM killing. Importantly, ex vivo activated NK cells traffic to the bone marrow in mice. Autologous NK cell therapy eliminates the issues related to allo-donor availability and early NK cell rejection, and could provide an option for patients refractory to chemotherapy agents. Figure Figure


2021 ◽  
Vol 12 ◽  
Author(s):  
Shahrokh Abdolahi ◽  
Zeinab Ghazvinian ◽  
Samad Muhammadnejad ◽  
Mohammad Ahmadvand ◽  
Hamid Asadzadeh Aghdaei ◽  
...  

Recently, adaptive NK cell therapy has become a promising treatment but has limited efficacy as a monotherapy. The identification of immune checkpoint inhibitor (ICI) molecules has opened a new horizon of immunotherapy. Herein, we aimed to demonstrate the cytotoxic effects of a polytherapy consisting of ex vivo expanded IL-2-activated NK cells combined with human anti-PD-1 antibody as an important checkpoint molecule in a xenograft gastric cancer mouse model. EBV-LCL cell is used as a feeder to promote NK cell proliferation with a purity of 93.4%. Mice (NOG, female, 6–8 weeks old) with xenograft gastric tumors were treated with PBS, ex vivo IL-2-activated NK cells, IL-2-activated NK cell along with human anti-PD-1 (Nivolumab), and IL-2-activated pretreated NK cells with anti-PD-1 antibody. The cytotoxicity of ex vivo expanded NK cells against MKN-45 cells was assessed by a lactate dehydrogenase (LDH) assay. Tumor volume was evaluated for morphometric properties, and tumor-infiltrating NK cells were assessed by immunohistochemistry (IHC) and quantified by flow cytometry. Pathologic responses were considered by H and E staining. Ex vivo LDH evaluation showed the cytotoxic potential of treated NK cells against gastric cancer cell line. We indicated that the adoptive transfer of ex vivo IL-2-activated NK cells combined with anti-PD-1 resulted in tumor growth inhibition in a xenograft gastric cancer model. Mitotic count was significantly decreased (*p &lt; 0.05), and the tumor was associated with improved infiltration of NK cells in the NK-anti-PD-1 pretreated group (*p &lt; 0.05). In conclusion, the combination approach of activated NK cells and anti-PD-1 therapy results in tumor growth inhibition, accompanied by tumor immune cell infiltration in the gastric tumor model.


Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 4035-4035 ◽  
Author(s):  
Gabi M Frei ◽  
Nurit Persi ◽  
Chana Lador ◽  
Amnon Peled ◽  
Yael C Cohen ◽  
...  

Abstract Abstract 4035 NK cells are cytotoxic lymphocytes that have drawn considerable attention in recent years as a promising tool for immunotherapy in patients with various refractory hematological malignancies and metastatic solid tumors. Clinical results of experimental protocols have shown only a partial response attributed mainly to the relatively low number of NK cells infused and their short in vivo persistence. An important challenge, therefore, in advancing the clinical applicability of NK cells is to expand ex vivo NK cells that display increased functionality upon in vivo infusion. In efforts to induce NK cell expansion, different combinations of cytokines have been studied. However, most reports show a modest expansion and demonstrate a need for additional stimuli. Nicotinamide (NAM) is a form of Vitamin B3 and a potent inhibitor of enzymes that use NAD for their activity. Hence, NAM is directly involved in the control of redox sensitive enzymes, mitochondrial functions, cell metabolism, the production of energy, and cell motility. Here we show that NAM (2.5–5 mM) enhances expansion (60-80 fold) of functional NK cells in feeder-free cultures stimulated with IL-2 and IL-15 for two weeks. This effect was observed in cultures initiated with purified CD56+ (CD56 enriched/CD3 depleted) or with CD3 depleted, peripheral blood and cord blood cells. Immunophenotyping of the cultured NK cells has so far revealed that NAM substantially modulates three cell surface receptors. CD200R and programmed death receptor-1 (PD-1) expressed on NK cells interact with their ligands on tumor cells which leads to a suppression in NK cell anti-tumor activity and tumor immunoevasion. These two receptors are down-regulated by NAM. CD62L (L-selectin) defines an NK subset with increased self-renewal capacity and its expression was reported to be pivotal for NK cells trafficking to lymphoid organs and their homeostatic proliferation. Following expansion in culture with IL-2, CD62L is down-regulated, whilst NAM increased its expression with a dose-dependent effect. Using a CFSE-based cytotoxicity assay we have demonstrated that NK cells cultured with NAM display higher cytotoxic activity against K562, BL2, NK-resistant COLO 205 cell lines and primary leukemia cells. In a Transwell migration assay, NK cells cultured with NAM demonstrated increased migration towards the CXCR4 ligand SDF-1. To test in vivo homing and retention, irradiated (350 RAD) NOD/SCID mice were transplanted with a similar number of cells (15–20×106 /mouse) derived from two week cultures treated with or without NAM. Mice were infused with 50μg/mouse IL-2 and 5μg/mouse IL-15 every other day. To test homing, mice were sacrificed 24 hour post infusion. Number of human NK cells (CD45+CD56+) detected in the spleen and BM were significantly (p< 0.05) higher in the cohort of mice infused with NK cells cultured with NAM (7.9 and 1.39 respectively) compared to mice infused with NK cells cultured without NAM (4.13 and 0, respectively). In a different set of experiments, persistence of human NK cells was analyzed 4 and 12 days post infusion. Four days post infusion, the percentage of human NK cells in the spleen, BM, lung and liver were substantially higher in mice infused with NK cells cultured with NAM compared to mice infused with NK cells cultured without NAM (Fig 1). Even though 12 days post infusion, a decrease in the number of human NK cells was observed in comparison to day 4, still cell retention in the spleen, liver and lung was significantly greater in the cohort infused with NK cells cultured with NAM (13.45, 0.6, 9.21% Vs. 1.26, 0.12, 2.85%, (p<0.05), respectively). The calculated decrease in the number of human NK cells from day 4 to 12 was 50% less in the NAM cohort, suggesting enhanced in vivo survival of NK cells cultured with NAM.Table 1:In vivo persistence of ex vivo expanded NK cellsTable 1:. In vivo persistence of ex vivo expanded NK cells In conclusion, expansion of NK cells with NAM was found to increase in vivo homing and survival and to augment tumor cytotoxic effect of NK cells. This suggests a potential for enhancing the clinical efficacy of adoptively transferred NK cells. Based on these intriguing findings we are developing a cell product for adoptive cell-mediated immune therapy. Disclosures: Frei: Gamida Cell: Employment. Persi:Gamida Cell: Employment. Lador:Gamida Cell: Employment, Equity Ownership. Peled:Gamida Cell: Consultancy. Nagler:Gamida Cell: Consultancy. Peled:Gamida Cell: Employment, Equity Ownership, Patents & Royalties.


2020 ◽  
Vol 21 (7) ◽  
pp. 2263 ◽  
Author(s):  
Farzaneh Sharifzad ◽  
Soura Mardpour ◽  
Saeid Mardpour ◽  
Esmaeil Fakharian ◽  
Adeleh Taghikhani ◽  
...  

Natural killer (NK) cell therapy is one of the most promising treatments for Glioblastoma Multiforme (GBM). However, this emerging technology is limited by the availability of sufficient numbers of fully functional cells. Here, we investigated the efficacy of NK cells that were expanded and treated by interleukin-2 (IL-2) and heat shock protein 70 (HSP70), both in vitro and in vivo. Proliferation and cytotoxicity assays were used to assess the functionality of NK cells in vitro, after which treated and naïve NK cells were administrated intracranially and systemically to compare the potential antitumor activities in our in vivo rat GBM models. In vitro assays provided strong evidence of NK cell efficacy against C6 tumor cells. In vivo tracking of NK cells showed efficient homing around and within the tumor site. Furthermore, significant amelioration of the tumor in rats treated with HSP70/Il-2-treated NK cells as compared to those subjected to nontreated NK cells, as confirmed by MRI, proved the efficacy of adoptive NK cell therapy. Moreover, results obtained with systemic injection confirmed migration of activated NK cells over the blood brain barrier and subsequent targeting of GBM tumor cells. Our data suggest that administration of HSP70/Il-2-treated NK cells may be a promising therapeutic approach to be considered in the treatment of GBM.


Cancers ◽  
2019 ◽  
Vol 11 (10) ◽  
pp. 1534 ◽  
Author(s):  
Sooyeon Oh ◽  
Joo-Ho Lee ◽  
KyuBum Kwack ◽  
Sang-Woon Choi

In treatments of solid tumors, adoptive transfer of ex vivo expanded natural killer (NK) cells has dawned as a new paradigm. Compared with cytotoxic T lymphocytes, NK cells take a unique position targeting tumor cells that evade the host immune surveillance by down-regulating self-antigen presentation. Recent findings highlighted that NK cells can even target cancer stem cells. The efficacy of allogeneic NK cells has been widely investigated in the treatment of hematologic malignancies. In solid tumors, both autologous and allogeneic NK cells have demonstrated potential efficacy. In allogeneic NK cell therapy, the mismatch between the killer cell immunoglobulin-like receptor (KIR) and human leukocyte antigen (HLA) can be harnessed to increase the antitumor activity. However, the allogeneic NK cells cause more adverse events and can be rejected by the host immune system after repeated injections. In this regard, the autologous NK cell therapy is safer. This article reviews the published results of clinical trials and discusses strategies to enhance the efficacy of the NK cell therapy. The difference in immunophenotype of the ex vivo expanded NK cells resulted from different culture methods may affect the final efficacy. Furthermore, currently available standard anticancer therapy, molecularly targeted agents, and checkpoint inhibitors may directly or indirectly enhance the efficacy of NK cell therapy. A recent study discovered that NK cell specific genetic defects are closely associated with the tumor immune microenvironment that determines clinical outcomes. This finding warrants future investigations to find the implication of NK cell specific genetic defects in cancer development and treatment, and NK cell deficiency syndrome should be revisited to enhance our understanding. Overall, it is clear that NK cell therapy is safe and promises a new paradigm for the treatment of solid tumors.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 11-12
Author(s):  
Stefan O. Ciurea ◽  
Jolie Schafer ◽  
Piyanuch Kongtim ◽  
Julianne Chen ◽  
Doris Soebbing ◽  
...  

Background: Allogeneic stem-cell transplantation (alloSCT) remains the only curative treatment for patients with advanced AML. However, only a minority of these patients achieve disease control prior to transplantation. Natural Killer (NK) cells have potent anti-leukemic activity but are functionally deficient in AML. Adoptive NK-cell therapy using high-doses of functionally active NK-cells could overcome these limitations. We previously developed an ex vivo NK-cell expansion method based on K562 feeder cells modified to express membrane bound IL-21 (mbIL-21) and 4-1BB ligand, (FC21), which resulted in high numbers of hyperfunctional FC21-NK cells with enhanced cytotoxicity and cytokine production. Here we report outcomes of a phase I clinical trial designed to assess the safety, feasibility and maximum tolerated dose (MTD) of haploidentical FC21-NK cells for patients with relapse/refractory (R/R) AML at MD Anderson Cancer Center. Methods: Eligible patients were ≥18 years, KPS ≥70 with good organ function. Patients with relapsed AML after alloSCT were eligible if they had no active GVHD and did not require immunosuppression. Haploidentical donors were selected based on KIR characteristics, when multiple donors were available. Donor NK cells were expanded over 3 weeks and cryopreserved. Three dose levels between 106-108 cells/kg were planned. Patients received cytoreductive chemotherapy with fludarabine 30 mg/m2/day and cytarabine 2 g/m2/day for 5 days (4 days for age &gt;60) and G-CSF (subsequently eliminated). 3-7 days after chemotherapy, patients received FC21-NK cell infusions 3 times per week, up to 6 infusions. Results: As of 4/14/2020, 15 patients were screened, 12 of whom were eligible and received the FC21-NK cells. Median age was 60 years (range 25-70); 6 (50%) had adverse cytogenetics, 8 (66.7%) had adverse ELN genetic risk, 6 (50%) had primary induction failure, 2 (16.7%) had CNS disease and 4 (33.3%) had secondary AML. Median number of prior treatment regimens was 5 (range 2-8), median blast count at enrollment was 47% (range 7-88). Median time from diagnosis to enrollment and to first NK-cell infusion was 16.6 (range 2.5-98.1) and 17.2 (range 3.1-98.6) months, respectively. Donor-recipient NK-cell alloreactivity was seen in 5 patients (41.7%). Median number of NK-cell infusion was 6 (range 3-6); 8 (66.7%) and 4 (33.3%) patients received NK-cell dose of 1 X106 and 1 X107 cells/kg, respectively. MTD was not reached. Seven patients had ANC recovery post-NK cell infusion with cumulative incidence (CI) of ANC recovery to 500/mm3 at 60 days of 58.3%. Eight patients (66.7%) achieved complete remission (CR) (N=4, 33.3%) or CR with incomplete hematologic recovery (CRi) (N=4, 33.3%) at 30 days post-NK cell infusion. One patient with CR had negative minimal residual disease (MRD). Five patients (41.7%) proceeded to haploidentical alloSCT from the same donor and were transplanted in CR/CRi, all but one with persistent MRD. With a median follow-up of 13 months (range 4.1-42.7), median OS and DFS were 17.6 and 3.3 months, and 28 and 20 months for patients receiving alloSCT, respectively. Other outcomes including 2-year OS, DFS, relapse and TRM are shown in Figure 1 and Table 1. No infusion related toxicity or cytokine release syndrome was observed. Two patients were evaluable for FC21-NK cell persistence with haplotype-specific anti-HLA antibodies. FC21-NK cells were detected 5 and 6 weeks after the last FC21-NK cell infusion, respectively. A progressive decrease of the blast population with progressive expansion of the FC21-NK cell population after repeated NK-cell infusions was noted in samples collected from one pt (Figure 2). Persistence is also being evaluated by STR chimerism. Conclusions: Multiple infusions of FC21-NK cells yielded unprecedented outcomes with 66.7% of patients responding and approximately half proceeding to alloSCT in a heavily pre-treated, ultra-refractory, high-risk patient population. Responses were observed irrespective of dose. FC21-NK cell therapy was very well tolerated with no attributable AEs and were shown to persist for at least 5 weeks after infusion. These encouraging results warrant further clinical evaluation of FC21-NK cells in R/R AML patients. Disclosures Ciurea: Kiadis Pharma: Current equity holder in publicly-traded company, Research Funding. Schafer:Kiadis Pharma: Current Employment. Shpall:Zelluna: Membership on an entity's Board of Directors or advisory committees; Adaptimmune: Membership on an entity's Board of Directors or advisory committees; Celgene: Membership on an entity's Board of Directors or advisory committees; Magenta: Membership on an entity's Board of Directors or advisory committees; Novartis: Membership on an entity's Board of Directors or advisory committees; Takeda: Other: Licensing Agreement. Konopleva:Calithera: Research Funding; Eli Lilly: Research Funding; Kisoji: Consultancy; Reata Pharmaceutical Inc.;: Patents & Royalties: patents and royalties with patent US 7,795,305 B2 on CDDO-compounds and combination therapies, licensed to Reata Pharmaceutical; Forty-Seven: Consultancy, Research Funding; Sanofi: Research Funding; AstraZeneca: Research Funding; Agios: Research Funding; Ablynx: Research Funding; AbbVie: Consultancy, Research Funding; Ascentage: Research Funding; Rafael Pharmaceutical: Research Funding; Cellectis: Research Funding; F. Hoffmann La-Roche: Consultancy, Research Funding; Genentech: Consultancy, Research Funding; Amgen: Consultancy; Stemline Therapeutics: Consultancy, Research Funding. Lee:Kiadis Pharma Netherlands B.V: Consultancy, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Champlin:Actinium: Consultancy; Johnson and Johnson: Consultancy; Omeros: Consultancy; DKMS America: Membership on an entity's Board of Directors or advisory committees; Cytonus: Consultancy; Genzyme: Speakers Bureau; Takeda: Patents & Royalties.


Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 3905-3905
Author(s):  
Rebecca Lopez ◽  
Andreas Lundqvist ◽  
Stephanie Sellers ◽  
Maria Berg ◽  
Muthalagu Ramanathan ◽  
...  

Abstract NK cell based immunotherapy represents a promising treatment approach for patients with cancer. Although preliminary clinical trials in humans suggest NK cell infusions can mediate anti-tumor effects, animal models are needed to provide insight into methods to enhance both the function and in vivo longevity of adoptively infused NK cells. Research conducted in our laboratory has shown that ex vivo expanded human NK cells are highly activated, up-regulating NKG2D, Granzyme B, TRAIL and Fas-ligand expression making them much more cytotoxic to tumor cells compared to freshly isolated NK cells. However, important questions remain regarding whether in vitro expansion alters the capacity of these cells to replicate, and traffic to tissues in vivo following their adoptive infusion into recipients. Differences in the genotype and phenotype of mouse NK cells compared to human NK cells limit the value of murine animal models to address these questions. In contrast to mice, Rhesus macaques have orthologues to most of the human MHC class I and II genes and possess NK cells expressing KIRs that are phenotypically and functionally similar to human NK cells, thus providing an excellent model system for evaluating questions related to adoptive NK cell therapy. We developed an in vitro method to expand macaque NK cells to characterize their in vivo longevity and tissue trafficking following adoptive infusion. Macaque NK cells were enriched from peripheral blood mononuclear cells by depleting CD3+ cells using immunomagnetic beads and were then expanded in vitro with autologous plasma and a human EBV-LCL feeder cell line using culture conditions identical to those used to expand NK cells from humans. NK cell cultures expanded 50- to 100-fold over 7 to 20 days, were greater than 99% CD3 negative, and had a similar phenotype to human NK cells including a large proportion of CD16/CD56 double positive cells, and ubiquitous expression of NKG2D, KIR2D, LFA-1, granzyme B, and CXCR3. In contrast to mice but analogous to human NK cells, macaque expanded NK cells upregulated surface expression of TRAIL and were highly cytotoxic to K562 cells and other human tumor lines (Figure). CFSE labelling of expanded NK cells did not alter their phenotype or tumor cytotoxic function. Data characterizing the longevity, proliferative capacity, and tissue trafficking patterns in the blood, bone marrow and lymph node of in vitro expanded and adoptively infused CFSE labeled NK cells (up to 1 × 108 NK Cells/kg i.v.) in macaque recipients will be presented from this analysis. Figure Figure


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