scholarly journals CD19 Target Activated Natural Killer (CD19.TaNK) Cellular Therapy: A Novel immunotherapeutic Approach to the Treatment of Non-Hodgkin Lymphoma (NHL)

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 4174-4174
Author(s):  
Ravi Dashnamoorthy ◽  
Afshin Beheshti ◽  
Saheli Sarkar ◽  
Pooja Sabhachandani ◽  
Frank C. Passero ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Lines ◽  
Nk Cell ◽  
Resistant Cell ◽  
Cytolytic Activity ◽  
Lymphoma Cells ◽  
Cd20 Antibody ◽  
Anti Cd20 ◽  
Targeted Immunotherapy ◽  
Cd20 Antibodies

Abstract Background: Continued improvement in the treatment of NHL is desired, especially via the incorporation of 'targeted' immunotherapy agents. This is especially important in B-cell NHL (bNHL) as resistance to rituximab anti-CD20 antibody, and now second-generation antibodies (e.g., obinutuzumab), may occur. Activated NK-92 (aNK-92) is a continuously growing cell line consisting of "pure" (100%) activated NK cells. These cells were subsequently bioengineered to express human anti-CD19 chimeric antigen receptor (CAR) recognizing CD19+ B cells. The goal of this project was to investigate the specificity and the efficacy of a novel 'off the shelf' targeted immunotherapy, CD19.TaNK, in a multitude of B-cell NHL cell lines, including anti-CD20 antibody resistant cell lines. Methods: Using gene expression profiling, Gene Set Enrichment Analysis and Ingenuity Pathway Analysis, we first investigated the expression of NK activation and inhibitory ligands in varied lymphoma cells. The bNHL cell lines, SUDHL10 (DLBCL), L540, L428 (Hodgkin lymphoma), HF1 (follicular), Raji (Burkitt's), and Mino (mantle cell) were purchased from ATCC and maintained in RPMI1640 medium. aNK and CD19.TaNK were supplied by NantKwest, Inc and were maintained in Myelocult supplemented with recombinant human IL-2 (500IU/ml). NK cell mediated cytotoxicity was determined using lactate dehydrogenase (LDH) release glucose-6-phosphate dehydrogenase (G6PD) release (aCella-tox assay). Briefly, 10,000 target bNHL cells were co-cultured with effector NK cells, at clinically relevant effector to target ratios (E:T 1:1-10:1) for 4 hours, and the supernatant was assayed for LDH or G6PD release. Percent cytotoxicity was determined based on the experimental levels of LDH or G6PD release from NK mediated bNHL cell lysis compared to maximum LDH or G6PD release from target cells. To determine if resistance to anti-CD20 antibodies would interfere with sensitivity to CD19.TaNK therapy, rituximab and obinutuzumab resistant bNHL cell lines (SUDHL4, SHUDHL10, and Raji) were established; cells were exposed to incremental increasing concentrations of antibody drugs (5-20μg/ml) over a period of 8 weeks. CD19, CD20 and CD30 expression in bNHL cells was determined by flow cytometry. Additionally, the efficacy of primary NK cells were determined against CD20 monoclonal antibody sensitive and resistant cell lines utilizing droplet microfluidics based assessment. Results: We observed that bNHL cell lines expressed a multitude of ligands associated with stimulating NK cell activity, while expression of inhibitory ligands was minimal. This indicates that NK cell interaction with bNHL cells is predicted to lead to overall robust antitumor immune response (Figure). Using LDH and G6PD release assays in bNHL cell lines, we observed increased cytolytic activity in an E:T ratio dependent manner, with Raji and L428 cells being the most sensitive to CD19.TaNK at 1:1 E:T ratio. Development of resistance to anti-CD20 antibodies (rituximab and obinutuzumab) resulted in significantly decreased down regulation of CD20, but not CD19 or CD30, as detected by flow cytometry. After direct contact with primary NK cells, we observed that rituximab resistant SUDHL10 cells were poorly sensitive (7%), while in rituximab sensitive cells, there was 22% cell loss. Moreover, at 4 hours using CD19.TaNK therapy (1:5 ratios), there was marked cytolytic activity with consistent high LDH release seen across all bNHL cell lines without differences noted regardless of rituximab or obinutuzumab resistance (ie, SUDHL4, SHUDHL10, and Raji). These results were further confirmed using live cell video microscopy measuring the cytolytic activity of CD19.TaNK versus bNHL cells. Conclusion: We identified that bNHL cells contain high expression levels of NK activation ligands and low amounts of inhibitory ligands and that CD19.TaNK immunotherapy had potent single-agent anti-tumor activity against a spectrum of bNHL cells. Furthermore, CD19.TaNK maintained high cytolytic activity in bNHL cells resistant to standard CD20 antibody therapy, which were poorly sensitive to innate NK cells. Ongoing analyses include systems biology studies to determine potential biologic mechanisms of activity of CD19.TaNK therapy as well as well as to help guide optimum combinatorial therapy. Figure Expression of NK activation and inhibitory ligands in lymphoma cells. Figure. Expression of NK activation and inhibitory ligands in lymphoma cells. Disclosures Boissel: NantKwest, Inc.: Employment. Evens:Takeda: Other: Advisory board.

Comparative Assessment of Different Clinically Utilized CD20 Directed Antibodies in Chronic Lymphocytic Leukemia (CLL) Cells Reveals Divergent NK-Cell, Monocyte and Macrophage Properties,

Blood ◽  
2011 ◽  
Vol 118 (21) ◽  
pp. 3717-3717 ◽  
Author(s):  
Sarwish Rafiq ◽  
Jonathan P. Butchar ◽  
Carolyn Cheney ◽  
Xiaokui Mo ◽  
David Jarjoura ◽  
...  
Keyword(s):  
Nk Cells ◽  
Effector Cell ◽  
Nk Cell ◽  
Conflicts Of Interest ◽  
Phase Iii ◽  
Cd20 Antibody ◽  
Anti Cd20 ◽  
The Impact ◽  
Differential Properties ◽  
Cd20 Antibodies

Abstract Abstract 3717 The anti-CD20 antibody rituximab represents the first therapy to contribute to prolongation of survival in CLL yet controversy exists as to how it promotes tumor elimination. Pre-clinical studies in CLL have suggested that innate immune cells, complement, and direct antibody killing might contribute to anti-CD20 antibody efficacy. Murine models of B-cell depletion by CD20 antibodies have shown monocytes to be the most important effector cell, although significant controversy around this point exists. Given the success of rituximab, second generation anti-CD20 antibodies (Ofatumumab and GA101 are now in phase III testing in CLL with reported improved direct (GA101), complement (Ofatumumab), or NK cell effector cell killing (GA101). To date, direct comparison of these three antibodies for direct, complement, and effector cell engagement has not been performed. Additionally, the impact of afucosylation engineering of GA101 on monocyte and macrophage function has not been reported. As a Type II anti-CD20 antibody, GA101 mediated significantly increased cell death (∼25%) without Fc crosslinking when compared to Ofatumumab or rituximab (5–8%). Direct cytotoxicity assessment of 19 pts with cross-linking demonstrated GA101 (25%) to mediate significantly greater (p=0.0003) killing than rituximab (15%) but not Ofatumumab (20%). Complement mediated killing was significantly increased over media with Ofatumumab (∼30%), whereas an average of only 5–10% killing was observed with rituximab or GA101. Immobilized GA101 significantly increased NK cell activation as detected by IFNg production and CD107a induction (p=0.005) more than rituximab or Ofatumumab. In addition, GA101 mediates 2 to 3 fold greater NK cell-mediated Antibody Dependent Cellular Cytotoxicity (ADCC) compared to Ofatumumab or rituximab at higher antibody concentrations, but not at concentrations less than 0.05 mg/ml. This enhanced ADCC with GA101 is seen with normal NK cells as well as NK cells from CLL patients. Ofatumumab mediated significantly greater (p=0.0001) NK cell ADCC than rituximab. Given the importance of macrophages in depletion of anti-CD20 tumors in mouse models of lymphoma, we next focused on this. The three anti-CD20 antibodies show Antibody Dependent Cellular Phagocytosis (ADCP) capability with Monocyte Derived Macrophages (MDM) against CLL B cells, with Ofatumumab exhibiting the greatest ADCP compared to GA101 (60% vs 40%; p=0.0036). In addition, primary monocytes stimulated with immobilized GA101 show less TNFa release, when compared to rituximab or Ofatumumab. To investigate this mechanistically, monocytes were stimulated with plate bound rituximab, Ofatumumab or GA101. Compared to the non Fc engineered antibodies (rituximab and Ofatumumab) Fc engineered GA101 induces reduced pan tyrosine phosphorylation and phosphorylation of ERK. No differences in phosphorylation of FcgRIIa or FcgRIIb was observed between the engineered and non-engineered antibodies. Further mechanistic studies to elucidate these differences in monocytes based upon antibody afucosylation changes, or differential phosphorylation of FcgR are ongoing. Collectively, our data indicate that GA101 and Ofatumumab are both superior to rituximab against CLL cells and have differential properties with respect to apoptosis, CDC, and effector cell-mediated killing. GA-101 mediates the most potent NK cell mediated killing at high concentrations whereas Ofatumumab has the greatest monocyte activation and phagocytosis despite absence of any engineering. These findings have relevance in the choice of the optimal CD20 antibody for treatment of CLL and combination strategies used. Disclosures: No relevant conflicts of interest to declare.

scholarly journals Anti-KIR antibody enhancement of anti-lymphoma activity of natural killer cells as monotherapy and in combination with anti-CD20 antibodies

Blood ◽  
2014 ◽  
Vol 123 (5) ◽  
pp. 678-686 ◽  
Author(s):  
Holbrook E. Kohrt ◽  
Ariane Thielens ◽  
Aurelien Marabelle ◽  
Idit Sagiv-Barfi ◽  
Caroline Sola ◽  
...  
Keyword(s):  
Natural Killer Cells ◽  
Natural Killer ◽  
Mhc Class I ◽  
Nk Cell ◽  
Class I ◽  
Lymphoma Cells ◽  
Killer Cells ◽  
Key Points ◽  
Anti Cd20 ◽  
Cd20 Antibodies

Key Points Blockade of inhibitory KIRs with MHC class I antigens on lymphoma cells by anti-KIR antibodies augments NK-cell spontaneous cytotoxicity. In combination with anti-CD20 mAbs, anti-KIR induces enhanced NK cell–mediated, rituximab-dependent cytotoxicity against lymphoma.

NK Cell Mediated Cytotoxicity Against Malignant Promyelocytes Enhanced By Arsenic Trioxide: Potential Clinical Relevance

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 1455-1455
Author(s):  
Ansu Abu Alex ◽  
Hamenth Kumar P ◽  
Saravanan Ganesan ◽  
Nithya Balasundaram ◽  
Kavitha M Lakshmi ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Line ◽  
Cell Lines ◽  
Nk Cell ◽  
Single Agent ◽  
Adaptive Immune System ◽  
Cytolytic Activity ◽  
Leukemic Cells ◽  
Ligand Expression ◽  
The Impact

Abstract NK cells are primary effectors of the innate immune response against cells that have undergone malignant transformation. Several lines of evidence indicate that the expression level of NK ligands on leukemic cells affects the sensitivity of the leukemic cells to cytolytic activity by NK cells. Various agents have been evaluated for their ability to induce these ligands on leukemic cells to augment the NK cell mediated anti-leukemia effect. There is substantial evidence that has established the importance of the adaptive immune system in the treatment of acute promyelocytic leukemia (APL) (Rose Ann Padua et al. Nat Med 2003). While there is significant data which address the mechanisms of arsenic trioxide (ATO) on malignant promyelocytes, limited data is available of its effect on the innate and adaptive immune system. We undertook a series of experiments to address the impact of ATO on NK cell receptor and malignant promyelocyte ligand expression and its effect on NK cell mediated cytotoxicity. We also evaluated NK cell reconstitution in patients treated with ATO and the impact of KIR genotypes on relapse. We first evaluated the cytotoxic activity of NK92MI (NK cell line) against 5 different myeloid (K562, U937, HL60, UF1, NB4) and 2 lymphoid cell lines (Jurkat E6.1, SUP-B15) by CFSE/ 7AAD cytotoxicity assay. Target (T) cells (1x 105/100 µL/well) pre-treated with CFSE were co-cultured with effector NK cells (E) at a E:T ratio of 1:1, 2:1 and 5:1 for 5 hours at 37°C in 96 well plates. The percentage cytolytic activity of the NK cells was then calculated after adding 7AAD and acquired in FACS Calibur (Becton Dickinson, San Jose, CA, USA). Significant cytolytic activity was noted against K562 and NB4 cell lines. At the highest E:T ratio there was a median 22% cytolytic activity against NB4 (N=5). We observed that NB4 when treated overnight with 1µM ATO (>99% viability retained after this exposure) significantly increased the cytotoxic effect of NK92MI cell line at all the E:T ratios as shown in figure 1A (n=5; P=0.0023). No other cell line showed a similar increase in cytotoxic effect following exposure to ATO at these concentrations (data not shown). We next evaluated the effect of exposure of NB4 cells to ATO at 1µM for 6 hours on NK ligand expression by flowcytometry. As shown in figure 1B there was a significant increase in activating ligand MICA/B in NB4 cell lines (n=3; P=0.016) which was not seen in any of the other cell lines. Similar significant increased expression of Nectin-2 (DNAM-1 ligand) and HLA Class I was seen. Exposure of NK92MI to ATO for 6 hours at 1uM (non cytotoxic dose:IC50-3.8uM) resulted in increased expression of activating receptors NKG2D, NKP30 and KIR2DS4 (figure 1C) and inhibitory receptor NKG2A and decrease in inhibitory receptors KIR3DL1/DL2. There were no changes in the expression of NKP46, KIR2DL1, KIR2DL2 and DNAM1 receptors. We undertook a prospective study to evaluate the pattern of NK (CD56+CD3-) reconstitution in patients with newly diagnosed APL treated at our center with a single agent ATO regimen (Mathews et al. JCO 2011). The mean NK cell counts in patients were below the 2SD deviation level of the normal range even after completion of therapy (approximately a year)(figure 1D). All other subsets evaluated (CD4, CD8, CD3, CD19, CD56+CD3+, CD4CD45RO) had returned to levels within the normal range by the end of consolidation therapy (approximately 3 months from diagnosis). KIR genotyping was done on 55 patients with APL who received treatment with single agent ATO based regimen. The median follow up of this cohort was 20 months and 14 cases relapsed following initial therapy. The presence or absence of 17 KIR genes was done by PCR-SSP method (KIR Typing kit, Miltenyi Biotech Inc, CA). There was no association with any specific genotype or haplotype with risk of relapse. In summary we have noted that there is up regulation of receptors on NK cells and ligands on malignant promyelocytes following exposure to ATO that favors NK cell mediated cytotoxicity. In-vitro we have demonstrated a significant increase in NK cell mediated cytolytic activity against malignant promyelocytes exposed to ATO even at relatively low E:T ratios. This could be an important mechanism by which ATO induces durable remissions in patients with APL. The delayed NK cell recovery following treatment with ATO raises the possibility of using NK cell therapy to augment the effect of ATO in the treatment of patients.Figure 1Figure 1. Disclosures: No relevant conflicts of interest to declare.

Negative Impact Of KIR/HLA Interactions On NK Cell Activity Can Be Overcome By The Glycoengineered Antibody GA101 (Obinutuzumab)

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 376-376
Author(s):  
Grzegorz Terszowski ◽  
Christian Klein ◽  
Jakob Passweg ◽  
Martin Stern
Keyword(s):  
B Cell ◽  
Nk Cells ◽  
Target Cell ◽  
Cell Activation ◽  
Nk Cell ◽  
Negative Impact ◽  
Target Cells ◽  
Cd107a Expression ◽  
Cd20 Antibody ◽  
Anti Cd20

Abstract Antibody dependent cellular cytotoxicity (ADCC) is one of the mechanisms by which therapeutic antibodies mediate tumor cell killing. The anti-CD20 antibody rituximab is the current standard of care in the treatment of B-cell lymphomas. GA101, a novel anti-CD20 antibody, contains a glycoengineered Fc-portion allowing approximately 10-fold greater affinity to FcgR3A, the Fc-IgG receptor expressed on the majority of natural killer (NK) cells. NK cell function is also regulated by inhibitory killer-cell immunoglobulin-like receptors (KIR), which interact with HLA class I antigens (2DL1-HLA-C2; 2DL2/3-HLA-C1, 3DL1-HLA-Bw4). The KIR/HLA interaction during NK cell development leads to the acquisition of full effector function in the “licensing” process, but also provides one of the main mechanisms of NK cell tolerance. The present study analyzed how KIR/HLA interactions influence ADCC, and whether there are differences between conventional and glycoengineered antibodies. We analyzed the activation (in terms of the degranulation measured by the CD107a expression) and killing capacity of KIR-positive NK cells induced by rituximab, GA101, and the parental non-Fc modified (wild-type) GA101wt. Target cells included HLA-negative B-cell lymphoma lines or B-cell lines expressing one or more HLA molecules. We confirmed previous observations that the licensing status affects the potential for rituximab-induced ADCC (degranulation against HLA-deficient 721.221 in licensed cells 35 ± 4% versus 19 ± 3% of unlicensed cells, p<0.01); and that KIR/HLA interactions strongly and selectively inhibit the response to targets expressing cognate HLA ligands (e.g. CD107a expression in KIR3DL1+ NK cells 17 ± 3% against 721.221-Bw4 cells, compared to 32 ± 4% against 721.221, p<0.01). Next, we analyzed rituximab-induced NK cell activation in donors expressing one, two, or three KIR ligands after co-incubation with target B-cell lines expressing corresponding HLA molecules. These experiments showed that the inhibitory effect during target cell encounter dominates over the activating effect of NK cell licensing, which leads to unlicensed NK cells being the strongest effectors of ADCC with rituximab (Figure, Panel A). We next compared the effect of the KIR/HLA interaction on rituximab-, GA101wt- and GA101-induced ADCC. GA101 largely compensated the hyporesponsiveness of unlicensed cells and NK cell activation was independent of the presence of HLA KIR ligands on target cells (Figure, Panel A). Finally, we addressed the question of how levels of NK cell degranulation correspond to target cell elimination. Correlation between CD107a expression and target cell elimination was excellent for all antibodies (Figure Panel B). GA101 induced the highest level of activation and the most effective target elimination. In contrast to rituximab and GA101wt, no negative impact of KIR/HLA interaction on degranulation or target cell elimination could be detected for GA101. In summary, we show that KIR/HLA interactions are relevant for ADCC with rituximab, with the negative impact during target cell encounter dominating over the positive effect of licensing. In contrast, the novel glycoengineered GA101 antibody overrides the negative signals derived from the KIR/HLA interaction and activates all NK cell subsets. These data suggest that the Fc-modification to enhance ADCC can be an effective strategy to augment the efficacy of therapeutic monoclonal antibodies by recruiting NK cells irrespective of their inhibitory KIR expression. Disclosures: Terszowski: Roche: Research Funding. Klein:Roche Glycart AG: Employment. Stern:Roche: Research Funding.

Reactive Oxygen Species Produced By Myeloid Cells Block CD20-Antibody Dependent NK Cell-Mediated Cytotoxicity Against Chronic Lymphocytic Leukemia Cells

Blood ◽  
2014 ◽  
Vol 124 (21) ◽  
pp. 3638-3638
Author(s):  
Olle Werlenius ◽  
Johan Aurelius ◽  
Maria Simpanen ◽  
Rebecca E Riise ◽  
Ali A Akhiani ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
Nk Cells ◽  
Nk Cell ◽  
Myeloid Cells ◽  
Oxidase Inhibitor ◽  
Lymphocytic Leukemia ◽  
Ros Production ◽  
Nadph Oxidase Inhibitor ◽  
Cd20 Antibody ◽  
Anti Cd20

Abstract Introduction: The addition of the anti-CD20 antibodies rituximab or ofatumumab to chemotherapy has improved the outcome for patients with chronic lymphocytic leukemia (CLL), but the efficacy of anti-CD20 monoclonal antibodies (mAbs) as single agents is limited. Immunosuppressive reactive oxygen species (ROS), produced by myeloid cells, including monocytes, may be a limiting factor for the efficacy of ADCC-dependent therapy. With the aim of reducing a potentially inhibitory role of ROS on mAb-dependent NK cell cytotoxicity against CLL cells, we performed in vitro cytotoxicity experiments in the presence of monocytes and the ROS formation inhibitor histamine dihydrochloride (HDC). Methods: After informed consent, blood samples were collected from Binet stage A CLL patients seen at Sahlgrenska University Hospital, Gothenburg, Sweden. NK cells, monocytes and CLL cells were isolated from PBMCs by immunomagnetic negative selection or flow cytometry. ROS production by monocytes was assessed by isoluminol-enhanced chemiluminescense upon stimulation with the chemotactic peptide fMLF in the presence or absence of CLL cells, rituximab (Roche), ofatumumab (GSK), HDC or the NADPH oxidase inhibitor DPI. NK cell death was assessed by flow cytometry after over-night culture of monocytes and lymphocytes. Autologous ADCC assays were performed with NK cells, monocytes and CFSE-labeled CLL cells in the presence or absence of rituximab, ofatumumab, HDC, catalase and interleukin-2 (IL-2). CLL cell death was determined by flow cytometry after live/dead staining. The study was approved by the local ethical review board of Gothenburg, and conducted in accordance with the declaration of Helsinki. Results: Rituximab and ofatumumab both triggered extracellular ROS production by monocytes. ROS production was blocked by the NADPH oxidase inhibitor DPI. Furthermore, monocytes induced ROS-dependent apoptosis in adjacent NK cells. In the cytotoxicity experiments, rituximab-mediated NK cell dependent cytotoxicity against CLL cells was significantly inhibited by the presence of autologous monocytes. This suppression, as well as the induction of NK cell apoptosis, were dependent on ROS, since both HDC and catalase significantly increased cytotoxicity and rescued NK cells from monocyte-induced apoptosis. Expectedly, IL-2 augmented NK cell-mediated ADCC. Conclusion: The results imply that CLL patients harbor immunosuppressive myeloid cells that reduce CD20-antibody dependent NK cell-mediated cytotoxicity against leukemic cells by producing ROS. We propose that treatment with HDC, preferably in conjunction with NK cell stimulatory cytokines, may improve anti-CD20-based immunotherapy in CLL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Reduction of Mitochondrial Membrane Potential Leads to Enhancement of Type-II CD20-Antibody Cytotoxicity in Diffuse Large B-Cell Lymphoma

Blood ◽  
2016 ◽  
Vol 128 (22) ◽  
pp. 1763-1763 ◽  
Author(s):  
Emma Vilventhraraja ◽  
Tetyana Klymenko ◽  
Jennifer Edelmann ◽  
John Gribben ◽  
Andrejs Ivanov
Keyword(s):  
Oxidative Phosphorylation ◽  
Cell Lines ◽  
Mitochondrial Function ◽  
Type I ◽  
Type Ii ◽  
Antibody Treatment ◽  
Respiratory Capacity ◽  
Cd20 Antibody ◽  
Anti Cd20 ◽  
Cd20 Antibodies

Abstract Diffuse Large B Cell Lymphoma (DLBCL) is the most prevalent non-Hodgkin lymphoma (NHL) in adults. Since the addition of the Type I anti-CD20 antibody Rituximab to chemotherapy, the overall survival of NHL patients has improved dramatically compared to the pre-Rituximab era. DLBCL however, has the worst survival rates out of all NHLs with an average 5-year survival of 55%. Unfortunately 40% of all DLBCL patients relapse within 2 years, and those that relapse or have refractory disease tend not to respond well to antibody-based salvage therapies. Since the discovery and utilisation of Rituximab, many have tried to enhance the efficacy of anti-CD20 antibodies in order to improve first-line treatment of DLBCL, leading to the evolution of Type II humanised anti-CD20 antibodies. The complete biological role of CD20 remains unclear, however it has been shown to act as part of an ion channel complex that is a component of the store operated calcium (Ca2+) system. This complex has the ability to facilitate mitochondrial membrane permeabilisation, resulting in reduced mitochondrial function. In order to investigate the effect of Type I- and Type II- anti-CD20 antibodies on mitochondrial function, we established a panel of 4 DLBCL cell lines. We used the XF Seahorse Mito Stress Test to reveal bioenergetic profiles of the cell lines before and after treatment with a panel of Type I and Type II anti-CD20 antibodies (2 Type-I and 2 Type-II anti-CD20 antibodies for each cell line). Basal oxidative phosphorylation (OxPhos), ATP production, and maximal and spare respiratory capacity of each sample were calculated as a measure of mitochondrial function. Next we used Metformin, a well-established inhibitor of oxidative phosphorylation to reduce the mitochondrial membrane potential (MMP) across our panel of cell lines. We confirmed MMP reduction by staining cells with JC-1, a chameleon dye used as an indicator of MMP and analysed samples using flow cytometry. We then used the XF Seahorse Mito Stress Test, this time to assess how combining each CD20-antibody with an OxPhos inhibitor effects mitochondrial function (10 conditions for each cell line). Finally, we used the same conditions to conduct clonogenic survival assays to see whether cytotoxicity of Type-I or Type-II anti-CD20 antibodies could be enhanced. We have observed that treatment with anti-CD20 antibodies results in a significant increase in the maximal respiratory capacity of our panel of cell lines. Conversely, pharmacological inhibition of oxidative phosphorylation causes a significant reduction in basal oxidative phosphorylation as well as a reduction in the maximal respiratory capacity of the cell lines in our panel. We also show that treatment combining an OxPhos inhibitor with either Type-I or Type-II CD20-antibodies prevents the increase in maximal respiratory capacity observed with CD20-antibody treatment alone. When analysing the clonogenic survival of cell lines we have found that only the cytotoxicity of Type-II anti-CD20 antibodies is enhanced by simultaneously treating cell lines with Metformin. We also used Annexin V/PI staining to assess cell death and show that inhibiting oxidative phosphorylation in conjunction with CD20-antibody treatment does not result in a significant increase in cell death across our panel of cell lines. Our data indicate for the first time that when cells are treated with CD20-antibodies they increase their maximal mitochondrial respiratory capacity to compensate for reduced basal mitochondrial function. We also show that inhibition of oxidative phosphorylation disables the cells from being able to compensate for the reduced mitochondrial function that is caused by CD20-antibody treatment. Importantly our data show that the reduction of mitochondrial function caused by combining Metformin with Type-II CD20 antibodies leads to a significant reduction in clonogenicity. We believe that understanding the mechanism of the inhibition of mitochondrial function will allow us to establish effective treatment combinations to significantly improve the efficacy of anti-CD20 antibody therapy in DLBCL. Disclosures No relevant conflicts of interest to declare.

scholarly journals Natural Killer (NK) Cell Expression of CD2 as a Predictor of Serial Antibody-Dependent Cell-Mediated Cytotoxicity (ADCC)

Antibodies ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 54
Author(s):  
Jennifer J.-J. Tang ◽  
Alexander P. Sung ◽  
Michael J. Guglielmo ◽  
Lydia Navarrete-Galvan ◽  
Doug Redelman ◽  
...  
Keyword(s):  
Nk Cells ◽  
Nk Cell ◽  
Target Cells ◽  
Dependent Cell ◽  
Cd20 Antibody ◽  
Daudi Cells ◽  
Serial Killing ◽  
Anti Cd20 ◽  
Cell Expression ◽  
Perforin Expression

NK cell ADCC supports monoclonal antibody anti-tumor therapies. We investigated serial ADCC and whether it could be predicted by NK phenotypes, including expression of CD16A, CD2 and perforin. CD16A, the NK receptor for antibodies, has AA158 valine or phenylalanine variants with different affinities for IgG. CD2, a costimulatory protein, associates with CD16A and can augment CD16A-signaling. Pore-forming perforin is essential for rapid NK-mediated killing. NK cells were monitored for their ADCC serial killing frequency (KF). KF is the average number of target cells killed per cell by a cytotoxic cell population. KF comparisons were made at 1:4 CD16pos NK effector:target ratios. ADCC was toward Daudi cells labeled with 51Cr and obinutuzumab anti-CD20 antibody. CD16A genotypes were determined by DNA sequencing. CD2, CD16A, and perforin expression was monitored by flow cytometry. Serial killing KFs varied two-fold among 24 donors and were independent of CD16A genotypes and perforin levels. However, high percentages of CD2pos of the CD16Apos NK cells and high levels of CD16A were associated with high KFs. ROC analysis indicated that the %CD2pos of CD16Apos NK cells can predict KFs. In conclusion, the extent of serial ADCC varies significantly among donors and appears predictable by the CD2posCD16Apos NK phenotype.

Targeting B-Cell Malignancies With Anti-CD20-Interleukin-21 Fusokine

Blood ◽  
2013 ◽  
Vol 122 (21) ◽  
pp. 377-377 ◽  
Author(s):  
Shruti Bhatt ◽  
Daxing Zhu ◽  
Xiaoyu Jiang ◽  
Seung-uon Shin ◽  
John M Timmerman ◽  
...  
Keyword(s):  
Cell Death ◽  
B Cell ◽  
Nk Cells ◽  
Cell Lines ◽  
Cell Lymphoma ◽  
B Cell Lymphoma ◽  
Cd20 Antibody ◽  
Anti Cd20

Abstract The anti-CD20 antibody rituximab has revolutionized the treatment for B cell non-Hodgkin lymphomas (NHLs). However, rituximab has limited effectiveness as a single agent in some NHL subtypes and its clinical efficacy is compromised by acquired drug resistance. As a result, many patients still succumb to NHLs. Hence, strategies that enhance the activity of anti-CD20 antibody may improve patient outcome. Interleukin-21 (IL21), a member of the IL2 cytokine family, exerts diverse regulatory effects on natural killer (NK), T and B cells. IL21 has been reported to possess potent anti-tumor activity against a variety of cancers not expressing IL21 receptor (IL21R) through activation of the immune system and is in clinical trials for renal cell carcinoma and metastatic melanoma. We have recently reported that apart from immuno-stimulatory effects, IL21 exerts direct cytotoxicity on IL21R expressing diffuse large B cell lymphoma (DLBCL) and mantle cell lymphoma (MCL) cell lines and primary tumors both in vitro as well in vivo (Sarosiek et al Blood 2010; Bhatt et al AACR 2013). Herein we designed a fusion protein comprising IL21 linked to the N-terminus of anti-CD20 antibody (αCD20-IL21 fusokine) to improve efficacy of its individual components and prolong IL21 half-life. We have verified the expression of full length fusion protein and demonstrated that αCD20-IL21 fusokine retained binding ability to its individual components; CD20 and IL21R, as analyzed by immunofluorescence and flow-cytometry analyses. Similar to our previous study of IL21 in DLBCL, treatment of B cell lymphoma cell lines with fusokine lead to phosphorylation of STAT1 and STAT3, upregulation of cMYC and BAX and downregulation of BCL-2 and BCL-XL, implying the activation of IL21R dependent signaling to trigger cytotoxic effects. In vitro, direct cell death induced by αCD20-IL21 fusokine in DLBCL (RCK8, WSU and Farage) and MCL (Mino, HBL2 and SP53) cell lines was markedly increased compared to its individual components (IL21 and parent αCD20-IgG1 antibody). More importantly, fusokine treatment resulted in cell death of MCL cell lines (L128, G519 and UPN1) that were found to be resistant to IL21 alone treatment. Furthermore, treatment of freshly isolated primary NHL cells with the αCD20-IL21 fusokine also exhibited a 40-50% increase in direct cell death compared to its individual components. Previous studies reported that IL21 enhances antibody-dependent cellular cytotoxicity (ADCC) of therapeutic antibodies by activation of NK cells. ADCC assays using chromium release with purified human NK cells demonstrated that ADCC induced by the parent antibody was enhanced in the presence of IL21 while IL21 alone had minimal effect on the lysis of Raji, Daudi, and Jeko1 target cells. Notably, αCD20-IL21 fusokine demonstrated increased ADCC activity in comparison to parent antibody plus IL21 in Raji, Daudi and Jeko-1 cells (p<0.001, p<0.005 and p<0.001, respectively). Similar results were obtained in primary MCL tumor cells. Consistent with this finding, fusokine treatment resulted in enhanced activation of the NK cells as assessed by CD69 upregulation and CD16 downregulation using flow-cytometry. Complement dependent cytotoxicity (CDC) of the fusokine was similar to the parent antibody and rituximab in Raji cells. Studies analyzing in vivo effects of the fusokine are in progress and will be presented at the meeting. These data strongly suggest that together with direct apoptotic potential, an anti-CD20 IL21 fusokine retains the ability to trigger indirect cell killing mediated via activation of immune effector cells. These dual effects may give remarkable advantage to the fusokine over existing anti-CD20 antibodies for the treatment of NHL tumors. Collectively, our study demonstrates that anti-tumor effects of IL21 and anti-CD20 antibodies can be enhanced by conjugation of IL21 with anti-CD20 antibody that may serve as a novel anti-lymphoma therapy. Disclosures: Rosenblatt: Seattle Genetics, Inc.: Research Funding.

Lymphomas are sensitive to perforin-dependent cytotoxic pathways despite expression of PI-9 and overexpression of bcl-2

Blood ◽  
2006 ◽  
Vol 107 (8) ◽  
pp. 3205-3211 ◽  
Author(s):  
Robert Godal ◽  
Ulrich Keilholz ◽  
Lutz Uharek ◽  
Anne Letsch ◽  
Anne Marie Asemissen ◽  
...  
Keyword(s):  
Nk Cells ◽  
Cell Lines ◽  
Immune Escape ◽  
Nk Cell ◽  
Granzyme B ◽  
Lymphoma Cells ◽  
Escape Mechanism ◽  
Proteinase Inhibitor 9 ◽  
Immune Escape Mechanism ◽  
The Impact

Abstract There is considerable interest in immunotherapeutic approaches for lymphoma. The expression of proteinase inhibitor 9 (PI-9), a molecule that inactivates granzyme B, is considered an immune escape mechanism in lymphoma. Further, lymphomas frequently overexpress the antiapoptotic molecule bcl-2, which is able to inhibit perforin-dependent cytotoxic pathways. In this study, the impact of PI-9 and bcl-2 expression on the sensitivity of lymphomas to T- and natural killer (NK) cell–mediated cytotoxicity was analyzed. We found PI-9 expression in 10 of 18 lymphoma cell lines and in 9 of 14 primary lymphomas. Overexpression of bcl-2 was found in 8 of 18 cell lines and in 12 of 14 primary lymphomas. All lymphoma cells were sensitive to cytolysis by specific T cells and cytokine-activated NK cells, and no difference in sensitivity was observed with respect to PI-9 or bcl-2 expression. Cytolysis was mediated predominantly through perforin-dependent pathways despite expression of PI-9 and bcl-2. Interestingly, the majority of lymphoma cells were resistant to cytolysis by resting allogeneic NK cells. This was due to the failure of lymphomas to induce degranulation of resting NK cells. These results show that resistance to perforin-dependent pathways is not a relevant immune escape mechanism in lymphoma and therefore is unlikely to impair clinical outcome of immunotherapeutic approaches.

scholarly journals Recent Advances to Augment NK Cell Cancer Immunotherapy Using Nanoparticles

Pharmaceutics ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 525
Author(s):  
Kwang-Soo Kim ◽  
Dong-Hwan Kim ◽  
Dong-Hyun Kim
Keyword(s):  
Clinical Trials ◽  
Nk Cells ◽  
Cancer Immunotherapy ◽  
Tumor Cells ◽  
Therapeutic Efficacy ◽  
Nk Cell ◽  
Cell Cancer ◽  
Immune Surveillance ◽  
Cytolytic Activity ◽  
Contact Frequency

Among various immunotherapies, natural killer (NK) cell cancer immunotherapy using adoptive transfer of NK cells takes a unique position by targeting tumor cells that evade the host immune surveillance. As the first-line innate effector cell, it has been revealed that NK cells have distinct mechanisms to both eliminate cancer cells directly and amplify the anticancer immune system. Over the last 40 years, NK cell cancer immunotherapy has shown encouraging reports in pre-clinic and clinic settings. In total, 288 clinical trials are investigating various NK cell immunotherapies to treat hematologic and solid malignancies in 2021. However, the clinical outcomes are unsatisfying, with remained challenges. The major limitation is attributed to the immune-suppressive tumor microenvironment (TME), low activity of NK cells, inadequate homing of NK cells, and limited contact frequency of NK cells with tumor cells. Innovative strategies to promote the cytolytic activity, durable persistence, activation, and tumor-infiltration of NK cells are required to advance NK cell cancer immunotherapy. As maturing nanotechnology and nanomedicine for clinical applications, there is a greater opportunity to augment NK cell therapeutic efficacy for the treatment of cancers. Active molecules/cytokine delivery, imaging, and physicochemical properties of nanoparticles are well equipped to overcome the challenges of NK cell cancer immunotherapy. Here, we discuss recent clinical trials of NK cell cancer immunotherapy, NK cell cancer immunotherapy challenges, and advances of nanoparticle-mediated NK cell therapeutic efficacy augmentation.

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