Engineering a Juxtamembrane-Targeting CAR T-Cell Against Mesothelin: A Novel Binder Resilient to Shed Antigen in Ovarian and Pancreatic Cancer.

Mesothelin is an attractive target for CAR-T therapy on a number of cancer types; however, the efficacy of this therapy is diminished because the bulk of the cell surface-expressed mesothelin is shed through naturally occurring proteolysis leaving behind a short juxtamembrane peptide 'stump'. The two problems this creates are (1) the bulk of the target protein is no longer on the tumor cell and (2), the free soluble shed mesothelin remains in the tumor microenvironment and becomes present in blood/other body fluids binding to the mesothelin-targeted CAR-T and interfering with their ability to target the mesothelin that remains on the surface of the tumor. These issues have likely contributed at least in part to the lack of desired efficacy of CAR-T cells that target membrane distal regions of mesothelin (i.

In vivo CAR T cell generation to treat cancer and autoimmune disease.

Chimeric antigen receptor (CAR) T cell therapies have transformed treatment of B cell malignancies. However, their broader application is limited by complex manufacturing processes and the necessity for lymphodepleting chemotherapy, restricting patient accessibility. We present an in vivo engineering strategy using targeted lipid nanoparticles (tLNPs) for messenger RNA delivery to specific T cell subsets.

Enhanced CAR T-Cell Therapy for Lymphoma after Previous Failure.

Background: Chimeric antigen receptor (CAR) T cells targeting CD19 have transformed the treatment of B-cell cancers, but many patients do not have long-term remission. We designed an anti-CD19 enhanced (armored) CAR T-cell product (huCART19-IL18) that secretes interleukin-18 to enhance antitumor activity.

Methods: In this study, we assessed the safety, feasibility, and preliminary efficacy of huCART19-IL18 in patients with relapsed or refractory lymphoma after previous anti-CD19 CAR T-cell therapy.

CAR Binders Affect CAR T-cell Tonic Signaling, Durability, and Sensitivity to Target.

Patients can develop human anti-mouse immune responses against CD19-specific chimeric antigen receptor (CAR) T cells due to the use of a murine CD19-specific single-chain variable fragment to redirect T cells. We screened a yeast display library to identify an array of fully human CD19 single-chain variable fragment binders and performed a series of studies to select the most promising fully human CAR. We observed significant differences in the ability of CARs employing these CD19 binders to be expressed on the cell surface, induce tonic signaling, redirect T-cell function, mediate tumor killing, recognize lower levels of CD19 antigen, and maintain function upon continuous antigen exposure.

LOXHD1 is an oncofusion-regulated antigen of ewing sarcoma.

Ewing Sarcoma (EwS) is a rare pediatric malignancy characterized by a unique t(11:22) (q24;q12) translocation resulting in the pathognomonic EWSR1::FLI1 fusion. Recent reports indicate that the EWSR1::FLI1 oncofusion drives aberrant expression of numerous transcripts, including Lipoxygenase Homology Domains 1 (LOXHD1). Given its highly restricted protein expression pattern and role in EwS tumorigenesis and metastasis, LOXHD1 may serve as a novel immunotherapeutic target in this malignancy.

The Glucose Transporter 5 Enhances CAR-T Cell Metabolic Function and Anti-tumour Durability.

Activated T cells undergo a metabolic shift to aerobic glycolysis to support the energetic demands of proliferation, differentiation, and cytolytic function. Transmembrane glucose flux is facilitated by glucose transporters (GLUT) that play a vital role in T cell metabolic reprogramming and anti-tumour function. GLUT isoforms are regulated at the level of expression and subcellular distribution.

Pretreatment with IL-15 and IL-18 rescues natural killer cells from granzyme B-mediated apoptosis after cryopreservation.

Human natural killer (NK) cell-based therapies are under assessment for treating various cancers, but cryopreservation reduces both the recovery and function of NK cells, thereby limiting their therapeutic feasibility. Using cryopreservation protocols optimized for T cells, here we find that ~75% of NK cells die within 24 h post-thaw, with the remaining cells displaying reduced cytotoxicity. Using CRISPR-Cas9 gene editing and confocal microscopy, we find that cryopreserved NK cells largely die via apoptosis initiated by leakage of granzyme B from cytotoxic vesicles.

IL7 increases targeted lipid nanoparticle-mediated mRNA expression in T cells in vitro and in vivo by enhancing T cell protein translation.

The use of lipid nanoparticles (LNP) to encapsulate and deliver mRNA has become an important therapeutic advance. In addition to vaccines, LNP-mRNA can be used in many other applications. For example, targeting the LNP with anti-CD5 antibodies (CD5/tLNP) can allow for efficient delivery of mRNA payloads to T cells to express protein.

Enhancing chimeric antigen receptor T cell therapy by modulating the p53 signaling network with Δ133p53α.

Chimeric antigen receptor (CAR) T cell dysfunction is a major barrier to achieving lasting remission in hematologic cancers, especially in chronic lymphocytic leukemia (CLL). We have shown previously that Δ133p53α, an endogenous isoform of the human TP53 gene, decreases in expression with age in human T cells, and that reconstitution of Δ133p53α in poorly functional T cells can rescue proliferation [A. M.

Immunotherapy targeting B cells and long-lived plasma cells effectively eliminates pre-existing donor-specific allo-antibodies.

Pre-existing anti-human leukocyte antigen (HLA) allo-antibodies constitute a major barrier to transplantation. Current desensitization approaches fail due to ineffective depletion of allo-specific memory B cells (Bmems) and long-lived plasma cells (LLPCs). We evaluate the efficacy of chimeric antigen receptor (CAR) T cells targeting CD19 and B cell maturation antigen (BCMA) to eliminate allo-antibodies in a skin pre-sensitized murine model of islet allo-transplantation.

Exercise as a community treatment for obesity and the metabolic disease epidemic.

The obesity epidemic has continued to rise at an alarming rate and has increased health complications in children, adolescents, and adults. Resistance training, aerobic training, and a combination of the two have been shown to be effective at reducing excess adiposity and improving outcomes of obesity. The continued development of programs, community centers, or medical exercise facilities prescribing these treatments is nearing an absolute necessity to slow the advancing nature of obesity and related metabolic diseases.

Desmoplastic stroma restricts T cell extravasation and mediates immune exclusion and immunosuppression in solid tumors.

The desmoplastic stroma in solid tumors presents a formidable challenge to immunotherapies that rely on endogenous or adoptively transferred T cells, however, the mechanisms are poorly understood. To define mechanisms involved, here we treat established desmoplastic pancreatic tumors with CAR T cells directed to fibroblast activation protein (FAP), an enzyme highly overexpressed on a subset of cancer-associated fibroblasts (CAFs). Depletion of FAP CAFs results in loss of the structural integrity of desmoplastic matrix.

Desmoplastic stroma restricts T cell extravasation and mediates immune exclusion and immunosuppression in solid tumors.

The desmoplastic stroma in solid tumors presents a formidable challenge to immunotherapies that rely on endogenous or adoptively transferred T cells, however, the mechanisms are poorly understood. To define mechanisms involved, we treat established desmoplastic pancreatic tumors with CAR T cells directed to fibroblast activation protein (FAP), an enzyme highly overexpressed on a subset of cancer-associated fibroblasts (CAFs). Depletion of FAPCAFs results in loss of the structural integrity of desmoplastic matrix.

Identifying highly active anti-CCR4 CAR T cells for the treatment of T-cell lymphoma.

A challenge when targeting T-cell lymphoma with chimeric antigen receptor (CAR) T-cell therapy is that target antigens are often shared between T cells and tumor cells, resulting in fratricide between CAR T cells and on-target cytotoxicity on normal T cells. CC chemokine receptor 4 (CCR4) is highly expressed in many mature T-cell malignancies, such as adult T-cell leukemia/lymphoma (ATLL) and cutaneous T-cell lymphoma (CTCL), and has a unique expression profile in normal T cells. CCR4 is predominantly expressed by type-2 and type-17 helper T cells (Th2 and Th17) and regulatory T cells (Treg), but it is rarely expressed by other T helper (Th) subsets and CD8+ cells.

Combined disruption of T cell inflammatory regulators Regnase-1 and Roquin-1 enhances antitumor activity of engineered human T cells.

A fundamental limitation of T cell therapies in solid tumors is loss of inflammatory effector functions, such as cytokine production and proliferation. Here, we target a regulatory axis of T cell inflammatory responses, Regnase-1 and Roquin-1, to enhance antitumor responses in human T cells engineered with two clinical-stage immune receptors. Building on previous observations of Regnase-1 or Roquin-1 knockout in murine T cells or in human T cells for hematological malignancy models, we found that knockout of either Regnase-1 or Roquin-1 alone enhances antitumor function in solid tumor models, but that knockout of both Regnase-1 and Roquin-1 increases function further than knockout of either regulator alone.

Chimeric antigen receptor T cells as adjuvant therapy for unresectable adenocarcinoma.

Incomplete surgery of solid tumors is a risk factor for primary treatment failure. Here, we have investigated whether chimeric antigen receptor T cells (CARTs) could be used as an adjuvant therapy to clear residual cancer cells. We tested the feasibility of this approach in two partial resection xenograft models using mesothelin-specific CARTs.

Monitoring Therapeutic Response to Anti-FAP CAR T Cells Using [18F]AlF-FAPI-74.

Purpose: Despite the success of chimeric antigen receptor (CAR) T-cell therapy against hematologic malignancies, successful targeting of solid tumors with CAR T cells has been limited by a lack of durable responses and reports of toxicities. Our understanding of the limited therapeutic efficacy in solid tumors could be improved with quantitative tools that allow characterization of CAR T-targeted antigens in tumors and accurate monitoring of response.

Experimental Design: We used a radiolabeled FAP inhibitor (FAPI) [18F]AlF-FAPI-74 probe to complement ongoing efforts to develop and optimize FAP CAR T cells.

Potentiating adoptive cell therapy using synthetic IL-9 receptors.

Synthetic receptor signalling has the potential to endow adoptively transferred T cells with new functions that overcome major barriers in the treatment of solid tumours, including the need for conditioning chemotherapy. Here we designed chimeric receptors that have an orthogonal IL-2 receptor extracellular domain (ECD) fused with the intracellular domain (ICD) of receptors for common γ-chain (γ) cytokines IL-4, IL-7, IL-9 and IL-21 such that the orthogonal IL-2 cytokine elicits the corresponding γ cytokine signal. Of these, T cells that signal through the chimeric orthogonal IL-2Rβ-ECD-IL-9R-ICD (o9R) are distinguished by the concomitant activation of STAT1, STAT3 and STAT5 and assume characteristics of stem cell memory and effector T cells.

Costimulation of γδTCR and TLR7/8 promotes Vδ2 T-cell antitumor activity by modulating mTOR pathway and APC function.

Background: Gamma delta (γδ) T cells are attractive effector cells for cancer immunotherapy. Vδ2 T cells expanded by zoledronic acid (ZOL) are the most commonly used γδ T cells for adoptive cell therapy. However, adoptive transfer of the expanded Vδ2 T cells has limited clinical efficacy.

BET bromodomain protein inhibition reverses chimeric antigen receptor extinction and reinvigorates exhausted T cells in chronic lymphocytic leukemia.

Chimeric antigen receptor (CAR) T cells have induced remarkable antitumor responses in B cell malignancies. Some patients do not respond because of T cell deficiencies that hamper the expansion, persistence, and effector function of these cells. We used longitudinal immune profiling to identify phenotypic and pharmacodynamic changes in CD19-directed CAR T cells in patients with chronic lymphocytic leukemia (CLL).