Abstract |
Natural killer (NK) cells are highly specialized effectors of the innate immune system that hold promise for adoptive cancer immunotherapy. Their cell killing activity is primarily mediated by the pro-apoptotic serine protease granzyme B (GrB), which enters targets cells with the help of the pore-forming protein perforin. We investigated expression of a chimeric GrB fusion protein in NK cells as a means to augment their antitumoral activity. For selective targeting to tumor cells, we fused the epidermal growth factor receptor (EGFR) peptide ligand transforming growth factor α (TGFα) to human pre-pro-GrB. Established human NKL natural killer cells transduced with a lentiviral vector expressed this GrB-TGFα (GrB-T) molecule in amounts comparable to endogenous wildtype GrB. Activation of the genetically modified NK cells by cognate target cells resulted in the release of GrB-T together with endogenous granzymes and perforin, which augmented the effector cells' natural cytotoxicity against NK-sensitive tumor cells. Likewise, GrB-T was released into the extracellular space upon induction of degranulation with PMA and ionomycin. Secreted GrB-T fusion protein displayed specific binding to EGFR-overexpressing tumor cells, enzymatic activity, and selective target cell killing in the presence of an endosomolytic activity. Our data demonstrate that ectopic expression of a targeted GrB fusion protein in NK cells is feasible and can enhance antitumoral activity of the effector cells.
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Authors | Pranav Oberoi, Robert A Jabulowsky, Hayat Bähr-Mahmud, Winfried S Wels |
Journal | PloS one
(PLoS One)
Vol. 8
Issue 4
Pg. e61267
( 2013)
ISSN: 1932-6203 [Electronic] United States |
PMID | 23573299
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Recombinant Fusion Proteins
- Transforming Growth Factor alpha
- ErbB Receptors
- Granzymes
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Topics |
- Apoptosis
- Cell Degranulation
- Cell Survival
- Cytotoxicity, Immunologic
- Drug Delivery Systems
- ErbB Receptors
(metabolism)
- Gene Expression
- Granzymes
(biosynthesis, genetics, metabolism)
- HEK293 Cells
- Humans
- Immunotherapy
- Jurkat Cells
- Killer Cells, Natural
(immunology, metabolism)
- Recombinant Fusion Proteins
(biosynthesis, genetics, metabolism)
- Transforming Growth Factor alpha
(biosynthesis, genetics, metabolism)
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