Improvement of T cell Functionality in Cancer Immunotherapy - Time to AKT

Contains fulltext : 207786.pdf (publisher's version ) (Open Access)Radboud University, 15 oktober 2019Promotor : Jansen, J.H. Co-promotores : Dolstra, H., Waart, A.B. van de

Comprehensive Phenotyping of T Cells Using Flow Cytometry

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Cell composition and expansion strategy can reduce the beneficial effect of AKT-inhibition on functionality of CD8(+) T cells

Contains fulltext : 229379.pdf (Publisher’s version ) (Open Access)AKT-inhibition is a promising approach to improve T cell therapies; however, its effect on CD4(+) T cells is insufficiently explored. Previously, we and others showed that AKT-inhibition during ex vivo CD8(+) T cell expansion facilitates the generation of polyfunctional T cells with stem cell memory-like traits. However, most therapeutic T cell products are generated from lymphocytes, containing CD4(+) T cells that can affect CD8(+) T cells dependent on the Th-subset. Here, we investigated the effect of AKT-inhibition on CD4(+) T cells, during separate as well as total T cell expansions. Interestingly, ex vivo AKT-inhibition preserved the early memory phenotype of CD4(+) T cells based on higher CD62L, CXCR4 and CCR7 expression. However, in the presence of AKT-inhibition, Th-differentiation was skewed toward more Th2-associated at the expense of Th1-associated cells. Importantly, the favorable effect of AKT-inhibition on the functionality of CD8(+) T cells drastically diminished in the presence of CD4(+) T cells. Moreover, also the expansion method influenced the effect of AKT-inhibition on CD8(+) T cells. These findings indicate that the effect of AKT-inhibition on CD8(+) T cells is dependent on cell composition and expansion strategy, where presence of CD4(+) T cells as well as polyclonal stimulation impede the favorable effect of AKT-inhibition

Ex vivo AKT-inhibition facilitates generation of polyfunctional stem cell memory-like CD8(+) T cells for adoptive immunotherapy

Contains fulltext : 196608.pdf (publisher's version ) (Open Access

Inhibition of Akt-signaling promotes the generation of superior tumor-reactive T cells for immunotherapy post allogeneic stem cell transplantation

Immunobiology of allogeneic stem cell transplantation and immunotherapy of hematological diseasesHematolog

PD-L1 siRNA-mediated silencing in acute myeloid leukemia enhances anti-leukemic T cell reactivity

Acute myeloid leukemia (AML) is an immune-susceptible malignancy, as demonstrated by its responsiveness to allogeneic stem cell transplantation (alloSCT). However, by employing inhibitory signaling pathways, including PD-1/PD-L1, leukemia cells suppress T cell-mediated immune attack. Notably, impressive clinical efficacy has been obtained with PD-1/PD-L1 blocking antibodies in cancer patients. Yet, these systemic treatments are often accompanied by severe toxicity, especially after alloSCT. Here, we investigated RNA interference technology as an alternative strategy to locally interfere with PD-1/PD-L1 signaling in AML. We demonstrated efficient siRNA-mediated PD-L1 silencing in HL-60 and patients' AML cells. Importantly, WT1-antigen T cell receptor(+) PD-1(+) 2D3 cells showed increased activation toward PD-L1 silenced WT1(+) AML. Moreover, PD-L1 silenced AML cells significantly enhanced the activation, degranulation, and IFN-γ production of minor histocompatibility antigen-specific CD8(+) T cells. Notably, PD-L1 silencing was equally effective as PD-1 antibody blockade. Together, our study demonstrates that PD-L1 silencing may be an effective strategy to augment AML immune-susceptibility. This provides rationale for further development of targeted approaches to locally interfere with immune escape mechanisms in AML, thereby minimizing severe toxicity. In combination with alloSCT and/or adoptive T cell transfer, this strategy could be very appealing to boost graft-versus-leukemia immunity and improve outcome in AML patients