Chimeric antigen receptor (CAR) T cell therapy represents a cutting-edge cancer treatment, making the development and testing of CAR T cells crucial for advancing this therapeutic strategy. We present a protocol for creating and characterizing human epidermal growth factor receptor 2 (HER2)- and glypican-3 (GPC3)-metabolic reprogramming (MR)-CAR T cells by overexpressing adenosine deaminase 1 (ADA1) and CD26 (also known as dipeptidylpeptidase-4 or DPP4). This approach effectively converts immunosuppressive adenosine into inosine, which supports T cell survival in glucose-deficient tumor microenvironments. The protocol includes producing retroviral vectors, generating CAR T cells, and conducting ecto-ADA1 activity, cytotoxicity, cell migration, and RNA sequencing assays. For complete details on the use and execution of this protocol, please refer to Hu et al.1.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

Chimeric antigen receptor (CAR) T cell therapy is hindered in solid tumor treatment due to the immunosuppressive tumor microenvironment and suboptimal T cell persistence. Current strategies do not address nutrient competition in the microenvironment. Hence, we present a metabolic refueling approach using inosine as an alternative fuel. CAR T cells were engineered to express membrane-bound CD26 and cytoplasmic adenosine deaminase 1 (ADA1), converting adenosine to inosine. Autocrine secretion of ADA1 upon CD3/CD26 stimulation activates CAR T cells, improving migration and resistance to transforming growth factor β1 suppression. Fusion of ADA1 with anti-CD3 scFv further boosts inosine production and minimizes tumor cell feeding. In mouse models of hepatocellular carcinoma and non-small cell lung cancer, metabolically refueled CAR T cells exhibit superior tumor reduction compared to unmodified CAR T cells. Overall, our study highlights the potential of selective inosine refueling to enhance CAR T therapy efficacy against solid tumors.
Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.

The PD-1/PD-L1 checkpoint pathway is important for regulating immune responses and can be targeted by immunomodulatory drugs to treat a variety of immune disorders. However, the precise protein-protein interactions required for the initiation of PD-1/PD-L1 signaling are currently unknown. Previously, we designed a series of first-generation PD-1 targeting peptides based on the native interface region of programmed death ligand 1 (PD-L1) that effectively reduced PD-1/PD-L1 binding. In this work, we further characterized the previously identified lead peptide, MN1.1, to identify key PD-1 binding residues and design an optimized peptide, MN1.4. We show MN1.4 is significantly more stable than MN1.1 in serum and retains the ability to block PD-1/PD-L1 complex formation. We further characterized the immunomodulatory effects of MN1.4 treatment by measuring markers of T cell activation in a co-culture model with ovarian cancer cells and peripheral blood mononuclear cells. We found MN1.4 treatment reduced cytokine secretion and suppressed T cell responses in a similar manner as recombinant PD-L1. Therefore, the PD-L1 interface region used to design MN1.4 appeared sufficient to initiate PD-1 signaling and likely represents the minimum necessary region of PD-L1 required for PD-1 recognition. We propose a peptide agonist for PD-1, such as MN1.4, could have several applications for treating autoimmune disorders caused by PD-1 deficiencies such as type 1 diabetes, inflammatory arthritis, or autoimmune side effects arising from monoclonal antibody-based cancer immunotherapies.
Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.

CAR T cell therapy has revolutionized the treatment of hematologic malignancies, but its efficacy in solid tumors remains limited due to the immunosuppressive nature of the tumor microenvironment and the inability of T cells to persist and traffic to the tumor site. While current strategies focus on enhancing CAR T cell activity through costimulatory molecules and cytokines, a critical yet often overlooked factor is the competition for nutrients between tumor cells and T cells in the nutrient-deprived tumor microenvironment. To address this challenge, we employed a selective metabolic refueling (MR) strategy by providing T cells with inosine as an alternative fuel source for growth and functionality. In this study, we engineered CAR T cells to co-express a membrane-bound CD26 and a cytoplasmic adenosine deaminase 1 (ADA1) fused to an anti-CD3 scFv. ADA1 irreversibly converts both intracellular and extracellular adenosine to inosine, overcoming adenosine-mediated immunosuppression and providing T cells with inosine for growth. The inclusion of an anti-CD3 scFv fusion partner and overexpressing CD26 boosts ADA1 capture in a membrane proximal manner, providing inosine for T cells and minimizing feeding the tumor cells. We demonstrate that ADA1 is conditionally secreted only in stress conditions and that it activates CAR T cells through trans-signaling in a tumor-specific manner. In addition, we show that, compared to unmodified CAR T cells, CD26-overexpressing CAR T cells have better migration capacity and are less susceptible to TGF-β1 suppression. Finally, we found that, in mice models of human hepatocellular carcinoma (GPC3-MR-CAR) and human non-small cell lung cancer (HER2-MR-CAR), metabolically refueled CAR T cells (MR-CAR) are more efficient in reducing tumor growth than unmodified CAR T cells. Thus, selective refueling CAR T cells using ADA1 and CD26 holds promise for improving the efficacy of CAR T cell therapy of solid tumors.

The human immunodeficiency virus epidemic continues in sub-Saharan Africa, and particularly affects adolescent girls and women who have limited access to antiretroviral therapy. Here we report that the risk of vaginal simian immunodeficiency virus (SIV)mac251 acquisition is reduced by more than 90% using a combination of a vaccine comprising V1-deleted (V2 enhanced) SIV envelope immunogens with topical treatment of the zinc-finger inhibitor SAMT-247. Following 14 weekly intravaginal exposures to the highly pathogenic SIVmac251, 80% of a cohort of 20 macaques vaccinated and treated with SAMT-247 remained uninfected. In an arm of 18 vaccinated-only animals without microbicide, 40% of macaques remained uninfected. The combined SAMT-247/vaccine regimen was significantly more effective than vaccination alone. By analysing immune correlates of protection, we show that, by increasing zinc availability, SAMT-247 increases natural killer cytotoxicity and monocyte efferocytosis, and decreases T-cell activation to augment vaccine-induced protection.
© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.