Contributions
Abstract: S254
Type: Oral Presentation
Session title: Cellular immunotherapy and gene therapy - Experimental
Background
Chimeric antigen receptor (CAR)-T cell therapy redirected to specific antigens on tumor cells is a promising immunotherapy strategy for various cancers. However, CAR-T cells can induce substantial toxic effects, and it is sometimes difficult to manufacture them because they are produced on an individual-patient basis. Using a non-viral gene delivery, the piggyBac-transposon system, we have developed a ligand-based CAR-T cells redirected to the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor (GMR, CD116/CD131 complex), highly expressed in subtypes of myeloid malignancies. PiggyBac transposon-mediated, peripheral blood-derived GMR CAR-T cells are abundant in a native or stem cell-like memory T cells, showing a persistent antitumor effect in a xenograft mouse model. Cord blood (CB) offers an attractive, allogeneic, off-the shelf source for immunotherapy and is widely used as an alternative source of stem cell for allogeneic hematopoietic stem cell transplantation. Additionally, administration of CAR-natural killer (NK) cells has been shown to have antitumor effects without major toxic effects, such as cytokine release syndrome, neurotoxicity, or graft-versus-host disease.
Aims
In this study, we engineered CB-derived GMR CAR-T and CAR-NK cells via the piggyBac transposon system for more effective and safer cellular therapeutics.
Methods
Mononuclear cells from frozen CB were electroporated with both GMR CAR-transposon and piggyBac-transposase plasmids. The electroporated cells were cultured in a defined T-cell medium supplemented with recombinant interleukin (IL)-7 and IL-15, or in a NK-cell medium supplemented with recombinant IL-2 and IL-15. The cells were collected after 14 days of culture. The GMR CAR-T and CAR-NK cells were counted, and CAR expression and immunophenotype were characterized. To examine the anti-tumor activity, CAR-T and CAR-NK cells were co-cultured with the human acute myeloid leukemia cell line MV4-11 at an E:T ratio of 1:1, 1:2, or 1:4.
Results
We obtained GMR CAR-T and CAR-NK cells from CB via the piggyBac transposon system. Most CAR-positive T cells exhibited the CD45RA+ CCR7+ phenotype, suggesting that they exhibited the native or stem-cell memory T-cell phenotype. CAR-T and CAR-NK cells eradicated almost all the MV4-11 cells in culture. The results of additional analyses ongoing at the time of the abstract submission will be disclosed at the annual meeting.
Conclusion
GMR CAR-T and CAR-NK cells can be successfully generated non-virally from CB via the piggyBac transposon system. This approach can greatly improve the limitations of current CAR-T therapies.
Keyword(s): Cancer immunotherapy, CAR-T, Cord blood, NK cell
Abstract: S254
Type: Oral Presentation
Session title: Cellular immunotherapy and gene therapy - Experimental
Background
Chimeric antigen receptor (CAR)-T cell therapy redirected to specific antigens on tumor cells is a promising immunotherapy strategy for various cancers. However, CAR-T cells can induce substantial toxic effects, and it is sometimes difficult to manufacture them because they are produced on an individual-patient basis. Using a non-viral gene delivery, the piggyBac-transposon system, we have developed a ligand-based CAR-T cells redirected to the granulocyte-macrophage colony-stimulating factor (GM-CSF) receptor (GMR, CD116/CD131 complex), highly expressed in subtypes of myeloid malignancies. PiggyBac transposon-mediated, peripheral blood-derived GMR CAR-T cells are abundant in a native or stem cell-like memory T cells, showing a persistent antitumor effect in a xenograft mouse model. Cord blood (CB) offers an attractive, allogeneic, off-the shelf source for immunotherapy and is widely used as an alternative source of stem cell for allogeneic hematopoietic stem cell transplantation. Additionally, administration of CAR-natural killer (NK) cells has been shown to have antitumor effects without major toxic effects, such as cytokine release syndrome, neurotoxicity, or graft-versus-host disease.
Aims
In this study, we engineered CB-derived GMR CAR-T and CAR-NK cells via the piggyBac transposon system for more effective and safer cellular therapeutics.
Methods
Mononuclear cells from frozen CB were electroporated with both GMR CAR-transposon and piggyBac-transposase plasmids. The electroporated cells were cultured in a defined T-cell medium supplemented with recombinant interleukin (IL)-7 and IL-15, or in a NK-cell medium supplemented with recombinant IL-2 and IL-15. The cells were collected after 14 days of culture. The GMR CAR-T and CAR-NK cells were counted, and CAR expression and immunophenotype were characterized. To examine the anti-tumor activity, CAR-T and CAR-NK cells were co-cultured with the human acute myeloid leukemia cell line MV4-11 at an E:T ratio of 1:1, 1:2, or 1:4.
Results
We obtained GMR CAR-T and CAR-NK cells from CB via the piggyBac transposon system. Most CAR-positive T cells exhibited the CD45RA+ CCR7+ phenotype, suggesting that they exhibited the native or stem-cell memory T-cell phenotype. CAR-T and CAR-NK cells eradicated almost all the MV4-11 cells in culture. The results of additional analyses ongoing at the time of the abstract submission will be disclosed at the annual meeting.
Conclusion
GMR CAR-T and CAR-NK cells can be successfully generated non-virally from CB via the piggyBac transposon system. This approach can greatly improve the limitations of current CAR-T therapies.
Keyword(s): Cancer immunotherapy, CAR-T, Cord blood, NK cell