EGFR-Targeted Granzyme B Expressed in NK Cells Enhances Natural Cytotoxicity and Mediates Specific Killing of Tumor Cells

Oberoi, Pranav; Jabulowsky, Robert A.; Bähr-Mahmud, Hayat; Wels, Winfried S.

doi:10.1371/journal.pone.0061267

Cited by 27 publications

(21 citation statements)

References 43 publications

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“…To date there are no reports on gene dosage effects regarding granzyme B, although it has been suggested that altered granzyme B expression contributes to increased tumor cell surveillance. 35,36 Interestingly, the amount of granzyme B protein was increased without a concomitant change in the level of mRNA, suggesting the involvement of microRNAs. Both perforin and granzyme B have been described as targets of microRNA-dependent regulation in NK cells.…”

Section: Discussionmentioning

confidence: 99%

Loss of STAT3 in murine NK cells enhances NK cell–dependent tumor surveillance

Gotthardt

Putz

Straka

et al. 2014

Blood

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Section: Discussionmentioning

confidence: 99%

Loss of STAT3 in murine NK cells enhances NK cell–dependent tumor surveillance

Gotthardt

Putz

Straka

et al. 2014

Blood

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“…The concept of recombinant immunotoxins has been extensively investigated in the field of targeted tumor therapy with various bacterial and human effector domains (30)(31)(32), including Gb (11,13,27,33). After binding to a disease-specific cell surface antigen, these immunotoxins are internalized, e.g., by receptor-mediated endocytosis, released from endosomal compartments into the cytoplasm, and efficiently kill the malignant cell by their catalytic activity.…”

Section: Figmentioning

confidence: 99%

Antimalarial Activity of Granzyme B and Its Targeted Delivery by a Granzyme B–Single-Chain Fv Fusion Protein

Kapelski

Almeida

Fischer

et al. 2015

Antimicrob Agents Chemother

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We present here the first evidence that granzyme B acts against Plasmodium falciparum (50% inhibitory concentration [IC 50 ], 1,590 nM; 95% confidence interval [95% CI], 1,197 to 2,112 nM). We created a novel antimalarial fusion protein consisting of granzyme B fused to a merozoite surface protein 4 (MSP4)-specific single-chain Fv protein (scFv), which targets the enzyme to infected erythrocytes, with up to an 8-fold reduction in the IC 50 (176 nM; 95% CI, 154 to 202 nM). This study confirms the therapeutic efficacies of recombinant antibody-mediated antimalarial immunotherapeutics based on granzyme B. Malaria is caused by parasites of the genus Plasmodium and remains one of the most widespread and dangerous infectious diseases, causing ϳ627,000 deaths worldwide per year (1). Among the six species that infect humans, Plasmodium falciparum causes the severest form of the disease (2). There is no effective vaccine against these parasites (3, 4), and resistances are emerging against a wide variety of antimalarial drugs (5). It was recently shown in vitro that natural killer (NK) cells can eliminate erythrocytes infected with P. falciparum (6) and that this is associated with the production of the serine protease granzyme B (Gb) (7). In vivo, NK cells are essential for protection against plasmodial infections in mice (8), and increased levels of circulating Gb are found in naturally infected humans (9).We therefore investigated the antimalarial effect of recombinant Gb on P. falciparum (strain 3D7A) in a standardized 72-h drug susceptibility assay starting with synchronized ring-stage parasites (10). Gb was produced in HEK293 cells with an N-terminal protective peptide fused to an enterokinase cleavage site (EGb) to suppress the enzymatic activity in the host cells, as previously described (11). Activity was restored by the enzymatic removal of this peptide using 0.02 U of recombinant enterokinase (Novagen; Merck) per g of protein (12). The restored enzymatic activity was confirmed using a colorimetric activity assay (13). Parasite growth was specifically inhibited by activated Gb, with a half-maximal inhibitory concentration (IC 50 ) of 1,590 nM (95% confidence interval [95% CI], 1,197 to 2,112 nM, calculated using the Hill equation in GraphPad Prism version 5). Undigested (inactive) EGb showed no inhibition ( Fig. 1 and Table 1). To our knowledge, this is the first time that the antimalarial activity of Gb has been directly confirmed in vitro.We developed a strategy to target Gb to the parasite and thus reduce the required dose. Targeted toxin delivery via the parasite transferrin receptor has already been reported (14,15). Although some authors claim to have identified and characterized this receptor (16, 17), others argue that iron uptake by the parasite is nonspecific and that the P. falciparum transferrin receptor remains elusive (18). Promising alternative targets include the merozoite surface proteins (MSPs), especially MSP1, MSP2, MSP4, and MSP8, which bear glycosylphosphatidylinositol (GPI) anchors and th...

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“…102 Finally, to better protect NK cells from the NK cell-inhibitory cytokine TGFβ, NK cells (NK-92) were genetically modified to express a dominant negative TGFβ receptor designed to neutralize TGFβ signaling. These cells were rendered resistant to the suppressive effects of the cytokine and were able to mediate antitumor activity.…”

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confidence: 99%

T-cell and natural killer cell therapies for hematologic malignancies after hematopoietic stem cell transplantation: enhancing the graft-versus-leukemia effect

Cruz

Bollard

2015

Haematologica

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Hematopoietic stem cell transplantation has revolutionized the treatment of hematologic malignancies, but infection, graft-versus-host disease and relapse are still important problems. Calcineurin inhibitors, T-cell depletion strategies, and immunomodulators have helped to prevent graft-versus-host disease, but have a negative impact on the graft-versus-leukemia effect. T cells and natural killer cells are both thought to be important in the graft-versus-leukemia effect, and both cell types are amenable to ex vivo manipulation and clinical manufacture, making them versatile immunotherapeutics. We provide an overview of these immunotherapeutic strategies following hematopoietic stem cell transplantation, with discussions centered on natural killer and T-cell biology. We discuss the contributions of each cell type to graft-versus-leukemia effects, as well as the current research directions in the field as related to adoptive cell therapy after hematopoietic stem cell transplantation. ABSTRACT

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EGFR-Targeted Granzyme B Expressed in NK Cells Enhances Natural Cytotoxicity and Mediates Specific Killing of Tumor Cells

Cited by 27 publications

References 43 publications

Loss of STAT3 in murine NK cells enhances NK cell–dependent tumor surveillance

Loss of STAT3 in murine NK cells enhances NK cell–dependent tumor surveillance

Antimalarial Activity of Granzyme B and Its Targeted Delivery by a Granzyme B–Single-Chain Fv Fusion Protein

T-cell and natural killer cell therapies for hematologic malignancies after hematopoietic stem cell transplantation: enhancing the graft-versus-leukemia effect

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