The effects of transgenically encoded human and mouse IL-18 on T cell proliferation and its application in boosting chimeric antigen receptor (CAR) T cells are presented. Robust enhancement of ...proliferation of IL-18-secreting human T cells occurred in a xenograft model, and this was dependent on TCR and IL-18R signaling. IL-18 augmented IFN-γ secretion and proliferation of T cells activated by the endogenous TCR. TCR-deficient, human IL-18-expressing CD19 CAR T cells exhibited enhanced proliferation and antitumor activity in the xenograft model. Antigen-propelled activation of cytokine helper ensemble (APACHE) CAR T cells displayed inducible expression of IL-18 and enhanced antitumor immunity. In an intact mouse tumor model, CD19-IL-18 CAR T cells induced deeper B cell aplasia, significantly enhanced CAR T cell proliferation, and effectively augmented antitumor effects in mice with B16F10 melanoma. These findings point to a strategy to develop universal CAR T cells for patients with solid tumors.
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•Augmented proliferation of synthetic IL-18-expressing human T cells•rIL-18 augments IFN-γ secretion and proliferation of anti-CD3 activated T cells•IL-18-secreting CD4+ T cells promote CD8+ T cells through a helper effect•IL-18 CAR T cells have superior proliferation and antitumor activity in mouse models
Hu et al. create IL-18-secreting chimeric antigen receptor T (IL-18-CAR T) cells to significantly boost CAR T cell proliferation and antitumor activity.
CRISPR-Cas9 gene editing provides a powerful tool to enhance the natural ability of human T cells to fight cancer. We report a first-in-human phase 1 clinical trial to test the safety and feasibility ...of multiplex CRISPR-Cas9 editing to engineer T cells in three patients with refractory cancer. Two genes encoding the endogenous T cell receptor (TCR) chains, TCRα (
) and TCRβ (
), were deleted in T cells to reduce TCR mispairing and to enhance the expression of a synthetic, cancer-specific TCR transgene (NY-ESO-1). Removal of a third gene encoding programmed cell death protein 1 (PD-1;
), was performed to improve antitumor immunity. Adoptive transfer of engineered T cells into patients resulted in durable engraftment with edits at all three genomic loci. Although chromosomal translocations were detected, the frequency decreased over time. Modified T cells persisted for up to 9 months, suggesting that immunogenicity is minimal under these conditions and demonstrating the feasibility of CRISPR gene editing for cancer immunotherapy.
Chimeric antigen receptor (CAR) T cells are a promising therapy for hematologic malignancies. B-cell maturation antigen (BCMA) is a rational target in multiple myeloma (MM).
We conducted a phase I ...study of autologous T cells lentivirally-transduced with a fully-human, BCMA-specific CAR containing CD3ζ and 4-1BB signaling domains (CART-BCMA), in subjects with relapsed/refractory MM. Twenty-five subjects were treated in 3 cohorts: 1) 1-5 x 108 CART-BCMA cells alone; 2) Cyclophosphamide (Cy) 1.5 g/m2 + 1-5 x 107 CART-BCMA cells; and 3) Cy 1.5 g/m2 + 1-5 x 108 CART-BCMA cells. No pre-specified BCMA expression level was required.
CART-BCMA cells were manufactured and expanded in all subjects. Toxicities included cytokine release syndrome and neurotoxicity, which were grade 3-4 in 8 (32%) and 3 (12%) subjects, respectively, and reversible. One subject died at day 24 from candidemia and progressive myeloma, following treatment for severe CRS and encephalopathy. Responses (based on treated subjects) were seen in 4/9 (44%) in cohort 1, 1/5 (20%) in cohort 2, and 7/11 (64%) in cohort 3, including 5 partial, 5 very good partial, and 2 complete responses, 3 of which were ongoing at 11, 14, and 32 months. Decreased BCMA expression on residual MM cells was noted in responders; expression increased at progression in most. Responses and CART-BCMA expansion were associated with CD4:CD8 T cell ratio and frequency of CD45RO-CD27+CD8+ T cells in the pre-manufacturing leukapheresis product.
CART-BCMA infusions with or without lymphodepleting chemotherapy are clinically active in heavily-pretreated MM patients.
NCT02546167.
University of Pennsylvania-Novartis Alliance and NIH.
The adoptive transfer of T lymphocytes reprogrammed to target tumour cells has demonstrated potential for treatment of various cancers
. However, little is known about the long-term potential and ...clonal stability of the infused cells. Here we studied long-lasting CD19-redirected chimeric antigen receptor (CAR) T cells in two patients with chronic lymphocytic leukaemia
who achieved a complete remission in 2010. CAR T cells remained detectable more than ten years after infusion, with sustained remission in both patients. Notably, a highly activated CD4
population emerged in both patients, dominating the CAR T cell population at the later time points. This transition was reflected in the stabilization of the clonal make-up of CAR T cells with a repertoire dominated by a small number of clones. Single-cell profiling demonstrated that these long-persisting CD4
CAR T cells exhibited cytotoxic characteristics along with ongoing functional activation and proliferation. In addition, longitudinal profiling revealed a population of gamma delta CAR T cells that prominently expanded in one patient concomitant with CD8
CAR T cells during the initial response phase. Our identification and characterization of these unexpected CAR T cell populations provide novel insight into the CAR T cell characteristics associated with anti-cancer response and long-term remission in leukaemia.
Next-Generation CAR T-cell Therapies Young, Regina M; Engel, Nils W; Uslu, Ugur ...
Cancer discovery,
07/2022, Volume:
12, Issue:
7
Journal Article
Open access
CD19- and B-cell maturation antigen (BCMA)-directed chimeric antigen receptor (CAR) T cells have enabled unprecedented responses in a subset of refractory patients with B-cell and plasma cell ...malignancies, leading to their approval by the FDA for the treatment of leukemia, lymphoma, and myeloma. These "living drugs" can become part of a synthetic immune system, persisting at least a decade in some patients. However, despite this tremendous impact, significant unmet treatment needs remain for patients with hematologic malignancies and solid cancers. In this perspective, we highlight recent innovations that advance the field toward production of a more potent and universal cellular immunotherapy of the future. Next-generation CAR T cells will incorporate advances in gene engineering and synthetic biology to enhance functionality and persistence, and reduce treatment-associated toxicities. The combination of autologous CAR T cells with various allogeneic cell treatment strategies designed to target the immunosuppressive tumor microenvironment will broaden the impact of future CAR T-cell therapies.
Cancer immunotherapy based on genetically redirecting T cells has been used successfully to treat B cell malignancies
. In this strategy, the T cell genome is modified by integration of viral vectors ...or transposons encoding chimaeric antigen receptors (CARs) that direct tumour cell killing. However, this approach is often limited by the extent of expansion and persistence of CAR T cells
. Here we report mechanistic insights from studies of a patient with chronic lymphocytic leukaemia treated with CAR T cells targeting the CD19 protein. Following infusion of CAR T cells, anti-tumour activity was evident in the peripheral blood, lymph nodes and bone marrow; this activity was accompanied by complete remission. Unexpectedly, at the peak of the response, 94% of CAR T cells originated from a single clone in which lentiviral vector-mediated insertion of the CAR transgene disrupted the methylcytosine dioxygenase TET2 gene. Further analysis revealed a hypomorphic mutation in this patient's second TET2 allele. TET2-disrupted CAR T cells exhibited an epigenetic profile consistent with altered T cell differentiation and, at the peak of expansion, displayed a central memory phenotype. Experimental knockdown of TET2 recapitulated the potency-enhancing effect of TET2 dysfunction in this patient's CAR T cells. These findings suggest that the progeny of a single CAR T cell induced leukaemia remission and that TET2 modification may be useful for improving immunotherapies.
Chimeric antigen receptor (CAR) T cell therapy has achieved remarkable success in hematological malignancies but remains ineffective in solid tumors, due in part to CAR T cell exhaustion in the solid ...tumor microenvironment. To study dysfunction of mesothelin-redirected CAR T cells in pancreatic cancer, we establish a robust model of continuous antigen exposure that recapitulates hallmark features of T cell exhaustion and discover, both in vitro and in CAR T cell patients, that CAR dysregulation is associated with a CD8+ T-to-NK-like T cell transition. Furthermore, we identify a gene signature defining CAR and TCR dysregulation and transcription factors, including SOX4 and ID3 as key regulators of CAR T cell exhaustion. Our findings shed light on the plasticity of human CAR T cells and demonstrate that genetic downmodulation of ID3 and SOX4 expression can improve the efficacy of CAR T cell therapy in solid tumors by preventing or delaying CAR T cell dysfunction.
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•CAR T cells under chronic antigen stimulation show hallmarks of T cell exhaustion•CAR dysregulation is associated with a CD8+ T-to-NK-like T cell transition•CAR T cells with NK-like transition were identified in patients after treatment•Unlike WT CAR T cells, ID3 and SOX4 knockout CAR T cells retain anti-tumor immunity
Continuous antigen exposure drives CAR T cell exhaustion and promotes CD8+ T-to-NK-like T cell transition. Transcription factors ID3 and SOX4 are upregulated during CAR dysfunction and regulate genes associated with exhaustion, including NK receptors. Knocking out ID3 and SOX4 in CAR T cells slows dysfunction and improves anti-tumor immunity.
Solid tumors exhibit heterogeneous microenvironments, often characterized by limiting concentrations of oxygen (O2), glucose, and other nutrients. How oncogenic mutations alter stress response ...pathways, metabolism, and cell survival in the face of these challenges is incompletely understood. Here we report that constitutive mammalian target of rapamycin complex 1 (mTORC1) activity renders hypoxic cells dependent on exogenous desaturated lipids, as levels of de novo synthesized unsaturated fatty acids are reduced under low O2. Specifically, we demonstrate that hypoxic Tsc2(-/-) (tuberous sclerosis complex 2(-/-)) cells deprived of serum lipids exhibit a magnified unfolded protein response (UPR) but fail to appropriately expand their endoplasmic reticulum (ER), leading to inositol-requiring protein-1 (IRE1)-dependent cell death that can be reversed by the addition of unsaturated lipids. UPR activation and apoptosis were also detected in Tsc2-deficient kidney tumors. Importantly, we observed this phenotype in multiple human cancer cell lines and suggest that cells committed to unregulated growth within ischemic tumor microenvironments are unable to balance lipid and protein synthesis due to a critical limitation in desaturated lipids.
Target-mediated toxicity is a major limitation in the development of chimeric antigen T-cell receptors (CAR) for adoptive cell therapy of solid tumors. In this study, we developed a strategy to ...adjust the affinities of the scFv component of CAR to discriminate tumors overexpressing the target from normal tissues that express it at physiologic levels. A CAR-expressing T-cell panel was generated with target antigen affinities varying over three orders of magnitude. High-affinity cells recognized target expressed at any level, including at levels in normal cells that were undetectable by flow cytometry. Affinity-tuned cells exhibited robust antitumor efficacy similar to high-affinity cells, but spared normal cells expressing physiologic target levels. The use of affinity-tuned scFvs offers a strategy to empower wider use of CAR T cells against validated targets widely overexpressed on solid tumors, including those considered undruggable by this approach.
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