Contributions
Abstract: S136
Type: Oral Presentation
Presentation during EHA23: On Friday, June 15, 2018 from 12:00 - 12:15
Location: Room A8
Background
Adoptive transfer of genetically modified T lymphocytes with tumor antigen-specific receptor has proven efficacy in cancer immunotherapy. However, in many patients the overall benefit is still limited due to various tumor escape mechanisms. Cell damage and metabolic/hypoxic stress in the tumor microenvironment (TME) can lead to a dysfunctional anti-tumor T cell response called T cell senescence. The tumor suppressor TP53 is a master molecule in the regulation of cell cycle and senescence. Few studies have demonstrated the critical role of p53 isoforms in the regulation of cellular senescence mainly in tumor cells. However, their role in tumor infiltrating lymphocytes (TILs) remains largely unexplored.
Aims
Strategies to prevent T cell senescence in the TME could improve T cell function leading to a more effective anti-tumor response. To better understand the role of Δ133p53α isoform in regulating the cell cycle and senescence we studied the cellular and metabolic phenotype as well as the effector function of the Δ133p53α-modified tumor-antigen (TA) specific human T cells.
Methods
T cells form healthy donors were retrovirally co-transduced with a TA-specific T cell receptor (TCR) together with the Δ133p53α isoform or an empty control vector. Modified T cells were characterized for the expression of key activating/inhibitory molecules, homing markers and their proliferation capacity by flow cytometry. Additionally, we determined the metabolic phenotype of the cells with an Agilent Seahorse XFp Analyzer. The effector functions i.e. cytokine secretion and antigen-specific killing capacity were assessed by Luminex immunoassay and long-term tumor colony-forming assay, respectively.
Results
Our analyses of human T cells simultaneously engineered with Δ133p53α-isoform and a TA-specific TCR revealed reduced cell surface expression of T-cell inhibitory molecules (i.e. PD-1 or TIGIT), senescence markers (CD57, CD160) and increased expression of the homing receptor CD62L upon TA stimulation. Interestingly, first comparative analyses between Δ133p53α-modified and control T-cells revealed changes in the cell’s metabolic program similar to quiescent/naïve T cells. Δ133p53α-T cells exhibited lower ATP production, oxygen consumption as well as lower glucose utilization. Upon antigen-specific stimulation, however, they increased their metabolic activity up to the levels of control cells or even slightly above. Importantly, while control T cells exhibited cellular senescence after several rounds in culture, Δ133p53α-expressing T cells remained highly proliferative, showed superior cytokine secretion and enhanced tumor-specific killing capacity.
Conclusion
Genetic modulation of p53 isoforms in human T lymphocytes represents a novel approach to circumvent tumor-mediated T-cell replicative senescence and to preserve long-term effector function of tumor-reactive T cells. We believe that this new approach could improve current adoptive T cell-based therapies.
Session topic: 25. Gene therapy, cellular immunotherapy and vaccination – Biology & Translational Research
Keyword(s): Adoptive immunotherapy, P53, Senescence, T cell
Abstract: S136
Type: Oral Presentation
Presentation during EHA23: On Friday, June 15, 2018 from 12:00 - 12:15
Location: Room A8
Background
Adoptive transfer of genetically modified T lymphocytes with tumor antigen-specific receptor has proven efficacy in cancer immunotherapy. However, in many patients the overall benefit is still limited due to various tumor escape mechanisms. Cell damage and metabolic/hypoxic stress in the tumor microenvironment (TME) can lead to a dysfunctional anti-tumor T cell response called T cell senescence. The tumor suppressor TP53 is a master molecule in the regulation of cell cycle and senescence. Few studies have demonstrated the critical role of p53 isoforms in the regulation of cellular senescence mainly in tumor cells. However, their role in tumor infiltrating lymphocytes (TILs) remains largely unexplored.
Aims
Strategies to prevent T cell senescence in the TME could improve T cell function leading to a more effective anti-tumor response. To better understand the role of Δ133p53α isoform in regulating the cell cycle and senescence we studied the cellular and metabolic phenotype as well as the effector function of the Δ133p53α-modified tumor-antigen (TA) specific human T cells.
Methods
T cells form healthy donors were retrovirally co-transduced with a TA-specific T cell receptor (TCR) together with the Δ133p53α isoform or an empty control vector. Modified T cells were characterized for the expression of key activating/inhibitory molecules, homing markers and their proliferation capacity by flow cytometry. Additionally, we determined the metabolic phenotype of the cells with an Agilent Seahorse XFp Analyzer. The effector functions i.e. cytokine secretion and antigen-specific killing capacity were assessed by Luminex immunoassay and long-term tumor colony-forming assay, respectively.
Results
Our analyses of human T cells simultaneously engineered with Δ133p53α-isoform and a TA-specific TCR revealed reduced cell surface expression of T-cell inhibitory molecules (i.e. PD-1 or TIGIT), senescence markers (CD57, CD160) and increased expression of the homing receptor CD62L upon TA stimulation. Interestingly, first comparative analyses between Δ133p53α-modified and control T-cells revealed changes in the cell’s metabolic program similar to quiescent/naïve T cells. Δ133p53α-T cells exhibited lower ATP production, oxygen consumption as well as lower glucose utilization. Upon antigen-specific stimulation, however, they increased their metabolic activity up to the levels of control cells or even slightly above. Importantly, while control T cells exhibited cellular senescence after several rounds in culture, Δ133p53α-expressing T cells remained highly proliferative, showed superior cytokine secretion and enhanced tumor-specific killing capacity.
Conclusion
Genetic modulation of p53 isoforms in human T lymphocytes represents a novel approach to circumvent tumor-mediated T-cell replicative senescence and to preserve long-term effector function of tumor-reactive T cells. We believe that this new approach could improve current adoptive T cell-based therapies.
Session topic: 25. Gene therapy, cellular immunotherapy and vaccination – Biology & Translational Research
Keyword(s): Adoptive immunotherapy, P53, Senescence, T cell