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Isolation and Expansion of Cytotoxic Cytokine-induced Killer T Cells for Cancer Treatment
Published on: January 24, 2020
Characterization of genetically altered, interleukin 2-independent natural killer cell lines suitable for adoptive
1Division of Hematology, Terry Fox Laboratory, BC Cancer Agency, Vancouver, Canada. ytam@rush.edu
Insights
Researchers created interleukin 2 (IL-2)-independent natural killer (NK) cell variants (NK-92MI and NK-92CI) for enhanced adoptive cellular immunotherapy. These modified NK-92 cells maintain high cytotoxicity without external IL-2, overcoming clinical limitations.
Area of Science:
- Immunology
- Cell Biology
- Biotechnology
Background:
- Natural Killer (NK) cell-based immunotherapy shows promise but relies on cytokines like interleukin 2 (IL-2).
- Sustained IL-2 administration for NK-92 cell activation is limited by toxicity, hindering effective clinical application.
- Developing IL-2-independent NK cells is crucial for prolonged, effective adoptive cellular immunotherapy.
Purpose of the Study:
- To engineer IL-2-independent variants of the NK-92 cell line for improved immunotherapy.
- To characterize and compare the biological and functional properties of these new variants with the parental NK-92 cells.
Main Methods:
- Particle-mediated gene transfer was used to transfect NK-92 cells with human IL-2 (hIL-2) cDNA.
- The resulting variants (NK-92MI and NK-92CI) were analyzed for hIL-2 expression and synthesis.
- Cytotoxicity assays, hematopoietic progenitor cell co-incubation, and radiosensitivity studies were performed.
Main Results:
- Two IL-2-independent variants, NK-92MI and NK-92CI, were successfully generated, expressing and synthesizing hIL-2.
- NK-92MI cells exhibited higher IL-2 synthesis than NK-92CI cells; parental cells showed no IL-2 expression.
- Both variants maintained high cytotoxicity comparable to parental NK-92 cells and did not harm hematopoietic progenitor cells.
- The IL-2-independent variants were more radiosensitive than parental NK-92 cells.
Conclusions:
- Particle-mediated gene transfer effectively created IL-2-independent NK-92 variants suitable for clinical use.
- These nonvirally transfected, IL-2-independent NK cells enable prolonged immunotherapy without exogenous IL-2 support.
- The engineered NK-92MI and NK-92CI cells offer a promising strategy for overcoming current limitations in NK cell therapy.
Abstract:
NK-92 is a highly cytotoxic natural killer (NK) tumor cell line that possesses properties that make it an excellent candidate for adoptive cellular immunotherapy. However, the cytotoxicity of NK cells is dependent on cytokines such as interleukin 2 (IL-2). Although NK-92 cells maintain cytotoxicity for a time after withdrawal of IL-2, clinical use will probably require prolonged treatment with fully activated cells to eliminate disease effectively. The ability to support cytotoxic cells with exogenously administered IL-2 is limited by associated toxicity. Therefore, we describe the transfection of the IL-2-dependent NK-92 cell line with human IL-2 (hIL-2) cDNA by particle-mediated gene transfer to create two IL-2-independent variants, NK-92MI and NK-92 CI, and describe their characterization and comparison with parental cells. Both variants were shown to contain, express, and synthesize the hIL-2 cDNA. IL-2 synthesis was higher in NK-92MI cells compared with NK-92CI cells, with no expression in parental cells. Functionally, the cytotoxicity of all three cell lines was similar and coincubation with IL-2-independent variants did not affect hematopoietic progenitor cells. NK-92MI and NK-92CI cells were more radiosensitive than NK-92 cells, with proliferation inhibited at lower radiation doses and increased morality and decreased cytotoxicity compared with parental cells. Data presented here show that we have created by particle-mediated gene transfer two IL-2-independent variants of NK-92 that are identical to parental cells in virtually all respects, including high cytotoxic activity. The nonviral transfection of these cells makes them suitable for clinical applications. These IL-2-independent cells should allow prolonged treatment with fully active natural killer cells without the need for exogenous IL-2 support.
