Designer T-cells and T-cell receptors for customized cancer immunotherapies

Negative intracellular regulators of T-cell receptor (TCR) signaling as potential antitumor immunotherapy targets

Immunotherapy strategies aim to mobilize immune defenses against tumor cells by targeting mainly T cells. Co-inhibitory receptors or immune checkpoints (ICPs) (such as PD-1 and CTLA4) can limit T cell receptor (TCR) signal propagation in T cells. Antibody-based blocking of immune checkpoints (immune checkpoint inhibitors, ICIs) enable escape from ICP inhibition of TCR signaling. ICI therapies have significantly impacted the prognosis and survival of patients with cancer. However, many patients remain refractory to these treatments. Thus, alternative approaches for cancer immunotherapy are needed. In addition to membrane-associated inhibitory molecules, a growing number of intracellular molecules may also serve to downregulate signaling cascades triggered by TCR engagement. These molecules are known as intracellular immune checkpoints (iICPs). Blocking the expression or the activity of these intracellular negative signaling molecules is a novel field of action to boost T cell-mediated antitumor responses. This area is rapidly expanding. Indeed, more than 30 different potential iICPs have been identified. Over the past 5 years, several phase I/II clinical trials targeting iICPs in T cells have been registered. In this study, we summarize recent preclinical and clinical data demonstrating that immunotherapies targeting T cell iICPs can mediate regression of solid tumors including (membrane associated) immune-checkpoint inhibitor refractory cancers. Finally, we discuss how these iICPs are targeted and controlled. Thereby, iICP inhibition is a promising strategy opening new avenues for future cancer immunotherapy treatments.

Adoptive Transfer of Photosensitizer-Loaded Cytotoxic T Cells for Combinational Photodynamic Therapy and Cancer Immuno-Therapy

Adoptive cell transfer (ACT) has shown remarkable therapeutic efficacy against blood cancers such as leukemia and lymphomas, but its effect is still limited due to the lack of well-defined antigens expressed by aberrant cells within tumors, the insufficient trafficking of administered T cells to the tumor sites, as well as immunosuppression induced by the tumor microenvironment (TME). In this study, we propose the adoptive transfer of photosensitizer (PS)-loaded cytotoxic T cells for a combinational photodynamic and cancer immunotherapy. Temoporfin (Foscan^®), a clinically applicable porphyrin derivative, was loaded into OT-1 cells (PS-OT-1 cells). The PS-OT-1 cells efficiently produced a large amount of reactive oxygen species (ROS) under visible light irradiation in a culture; importantly, the combinational photodynamic therapy (PDT) and ACT with PS-OT-1 cells induced significant cytotoxicity compared to ACT alone with unloaded OT-1 cells. In murine lymphoma models, intravenously injected PS-OT-1 cells significantly inhibited tumor growth compared to unloaded OT-1 cells when the tumor tissues were locally irradiated with visible light. Collectively, this study suggests that combinational PDT and ACT mediated by PS-OT-1 cells provides a new approach for effective cancer immunotherapy.

Prognostic Value of the Neutrophil-to-Lymphocyte Ratio in Patients Treated with Definitive Chemoradiotherapy for Locally Advanced Oesophageal Squamous Cell Carcinoma

Background

The neutrophil-to-lymphocyte ratio (NLR) has been shown to have prognostic value in several common cancers. This study aimed to investigate the prognostic value of NLR in patients with advanced oesophageal squamous cell carcinoma (ESCC) after definitive chemoradiotherapy (dCRT).

Methods

A retrospective analysis was performed on 158 patients with advanced ESCC who received dCRT from January 2012 to December 2018. The NLR for different treatment stages was calculated based on laboratory test results. The Kaplan-Meier (KM) method and Cox proportional regression model were used to analyse the relationship between NLR and overall survival (OS).

Results

The mean NLR of 158 patients with ESCC was 3.403 ± 2.479. The pre-treatment NLR cut-off was 4.839, and patients were divided into the low NLR group (NLR < 4.839) and the high NLR group (NLR ≥ 4.839). NLR in patients with ESCC was related to N stage (P < 0.05). The KM analysis showed that the median OS of all enrolled patients was 29.3 months, the median OS periods of patients in the high and low NLR groups were 15.6 and 35.8 months, respectively, and the OS of the low NLR group was better than that of the high NLR group (P < 0.001). In the multivariate analysis, NLR was an independent prognostic factor that affects the prognosis of patients with ESCC receiving dCRT. Furthermore, patients who maintained a high NLR before and after treatment showed worse clinical outcomes than the other groups.

Conclusion

Our findings suggest that NLR can effectively assess the prognosis of patients with advanced ESCC undergoing dCRT.

Time 2EVOLVE: predicting efficacy of engineered T-cells - how far is the bench from the bedside?

Immunotherapy with gene engineered CAR and TCR transgenic T-cells is a transformative treatment in cancer medicine. There is a rich pipeline with target antigens and sophisticated technologies that will enable establishing this novel treatment not only in rare hematological malignancies, but also in common solid tumors. The T2EVOLVE consortium is a public private partnership directed at accelerating the preclinical development of and increasing access to engineered T-cell immunotherapies for cancer patients. A key ambition in T2EVOLVE is to assess the currently available preclinical models for evaluating safety and efficacy of engineered T cell therapy and developing new models and test parameters with higher predictive value for clinical safety and efficacy in order to improve and accelerate the selection of lead T-cell products for clinical translation. Here, we review existing and emerging preclinical models that permit assessing CAR and TCR signaling and antigen binding, the access and function of engineered T-cells to primary and metastatic tumor ligands, as well as the impact of endogenous factors such as the host immune system and microbiome. Collectively, this review article presents a perspective on an accelerated translational development path that is based on innovative standardized preclinical test systems for CAR and TCR transgenic T-cell products.

BCMA peptide-engineered nanoparticles enhance induction and function of antigen-specific CD8+ cytotoxic T lymphocytes against multiple myeloma: clinical applications

The purpose of these studies was to develop and characterize B-cell maturation antigen (BCMA)-specific peptide-encapsulated nanoparticle formulations to efficiently evoke BCMA-specific CD8+ cytotoxic T lymphocytes (CTL) with poly-functional immune activities against multiple myeloma (MM). Heteroclitic BCMA72-80 [YLMFLLRKI] peptide-encapsulated liposome or poly(lactic-co-glycolic acid) (PLGA) nanoparticles displayed uniform size distribution and increased peptide delivery to human dendritic cells, which enhanced induction of BCMA-specific CTL. Distinct from liposome-based nanoparticles, PLGA-based nanoparticles demonstrated a gradual increase in peptide uptake by antigen-presenting cells, and induced BCMA-specific CTL with higher anti-tumor activities (CD107a degranulation, CTL proliferation, and IFN-γ/IL-2/TNF-α production) against primary CD138+ tumor cells and MM cell lines. The improved functional activities were associated with increased Tetramer+/CD45RO+ memory CTL, CD28 upregulation on Tetramer+ CTL, and longer maintenance of central memory (CCR7+ CD45RO+) CTL, with the highest anti-MM activity and less differentiation into effector memory (CCR7- CD45RO+) CTL. These results provide the framework for therapeutic application of PLGA-based BCMA immunogenic peptide delivery system, rather than free peptide, to enhance the induction of BCMA-specific CTL with poly-functional Th1-specific anti-MM activities. These results demonstrate the potential clinical utility of PLGA nanotechnology-based cancer vaccine to enhance BCMA-targeted immunotherapy against myeloma.