IPSC-derived Trimodal T cells engineered with CAR, TCR, and hnCD16 modalities can overcome antigen escape in heterogenous tumors
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ABSTRACT: Although chimeric antigen receptor (CAR) T cells have demonstrated remarkable therapeutic activity in hematopoietic malignancies, antigen escape and tumor heterogeneity have in part impeded the durable efficacy of CAR T cells and their extension into successful solid tumor treatment. To address these challenges, induced pluripotent stem cell (iPSC) - derived T (iT) cells were specifically engineered to uniformly express both CAR and T cell receptors (TCR), enabling targeting of both surface and intracellular antigens, respectively, along with a high-affinity, non-cleavable variant of CD16a (hnCD16) to support antibody-dependent cell cytotoxicity (ADCC) when combined with therapeutic antibodies. Co-expression of each of these unique anti-tumor targeting strategies on engineered iT cells enabled independent and antigen-specific tumor cell killing across a diverse set of liquid and solid tumors. In heterogenous tumor models, coactivation of two or more of these effector modalities was required for measurable anti-tumor efficacy, with all three displaying maximal efficacy. These data highlight the therapeutic potential of an off-the-shelf engineered iPSC-derived Trimodal T cell expressing CAR, TCR, and hnCD16 to combat difficult to treat heterogeneous tumors.
Project description:Chimeric antigen receptor-modified (CAR) T cell therapy targeting highly expressed lineage antigens is effective for B cell malignancies. Achieving durable efficacy for hematological malignancies and extending this therapeutic approach to solid tumors will require T cell recognition and elimination of tumor cells that may express lower levels of the CAR target antigen. Realizing this goal is challenging because current approaches to CAR design are largely empiric and detailed information on CAR signaling is only beginning to emerge. Synthetic CARs typically require hundreds of molecules on the target cell to initiate signaling, whereas natural T cell receptors (TCRs) can recognize less than ten peptide-MHC (pMHC) antigen complexes. We reasoned that in depth comparison of TCR and CAR stimulation-induced signaling events in primary T cells might guide rationale adaptations to CAR design that would improve antigen sensitivity. Bi-specific T cells possessing an endogenous TCR and exogenous CAR of defined specificity were formulated from healthy HLA-B8+ Epstein-Barr virus-seropositive donors. Bi-specific T cells were stimulated with magnetic microbeads coated with recombinant TCR or CAR antigen for 10, 45, or 90 minutes. Some bi-specific T cells were also left unstimulated and harvested at each timepoint to serve as controls. Altogether, 9 unique conditions were tested in an experiment and three independent experiments were performed.
Project description:Chimeric antigen receptor (CAR)-T cell therapies have shown great success in treating hematologic malignancies. Nonetheless, their therapeutic effect on solid tumors remains to be improved. Recently, macrophages have attracted great attention, given their ability to infiltrate solid tumors, phagocytize tumor cells as well as their immunomodulatory capacities. The first generation of CD3ζ-based CAR-macrophages demonstrated that the CAR could stimulate macrophage phagocytosis in a tumor antigen-dependent way. Here, we genetically engineered induced pluripotent stem cell (iPSC)-derived macrophages (iMACs) with TLR4 intracellular TIR domain-containing CARs against EGFRvIII and GPC3, which yielded markedly enhanced antitumor effect in two different solid tumor models including glioblastoma, and hepatocellular carcinoma in which complete remission was achieved with CAR-iMACs alone or in combination with CD47 antibody. Moreover, the tandem CD3ζ-TIR-CAR, or the “second-generation” design of TIR-based dual signaling CAR, endowed iMACs with both target engulfment/efferocytosis capacity against antigen-expressing solid tumor cells, and potency of antigen-dependent M1 state polarization and M2 state resistance in an NF-κB dependent manner. We also illustrated a surprising mechanism of tumor cell elimination by CAR-induced efferocytosis against tumor cell apoptotic bodies. Taken together, we established the next generation CAR-iMACs equipped with orthogonal phagocytosis and polarization capacity for better antitumor functions in treating solid tumors.
Project description:Chimeric antigen receptor (CAR) and T-cell receptor (TCR) T-cell therapies are effective in a subset of patients with solid tumors, but new approaches are needed to enhance efficacy and universally improve patient outcomes. IL-15 and IL-21 are common cytokine-receptor gamma chain family members with distinct, pleiotropic effects on T-cells and other lymphocytes. We found that self-delivery of these cytokines by CAR or TCR T-cells prevents functional exhaustion by repeated stimulation and limits the emergence of dysfunctional natural killer (NK)-like T-cells. Across different preclinical murine solid tumor models, we observe enhanced regression with each individual cytokine but the greatest anti-tumor efficacy when T-cells are armored with both. Thus, the co-expression of membrane-tethered IL-15 and IL-21 represents a technology to enhance the resilience and function of engineered T-cells against solid tumors and could be applicable to multiple therapy platforms and diseases.
Project description:The efficacy of Chimeric Antigen Receptor (CAR) T cells against solid tumors is limited by immunosuppressive factors in the tumor microenvironment (TME) including adenosine, which suppresses CAR T cells through activation of the A2A receptor (A2AR). To overcome this, CAR T cells were engineered to express A1 receptor (A1R), a receptor that signals inversely to A2AR. Using murine and human CAR T cells, constitutive A1R overexpression was demonstrated to significantly enhance CAR T cell effector function albeit at the expense of CAR T cell persistence. Through a novel CRISPR/Cas9 “knock-in” approach we demonstrated that CAR T cells engineered to express A1R in a tumor-localized manner, led to enhanced anti-tumor efficacy dependent on the transcription factor IRF8 and was transcriptionally unique when compared to A2AR deletion. This data provides a novel approach for enhancing CAR T cell efficacy in solid tumors and provides proof of principle for site-directed expression of factors that promote effector T cell differentiation.
Project description:The efficacy of Chimeric Antigen Receptor (CAR) T cells against solid tumors is limited by immunosuppressive factors in the tumor microenvironment (TME) including adenosine, which suppresses CAR T cells through activation of the A2A receptor (A2AR). To overcome this, CAR T cells were engineered to express A1 receptor (A1R), a receptor that signals inversely to A2AR. Using murine and human CAR T cells, constitutive A1R overexpression was demonstrated to significantly enhance CAR T cell effector function albeit at the expense of CAR T cell persistence. Through a novel CRISPR/Cas9 “knock-in” approach we demonstrated that CAR T cells engineered to express A1R in a tumor-localized manner, led to enhanced anti-tumor efficacy dependent on the transcription factor IRF8 and was transcriptionally unique when compared to A2AR deletion. This data provides a novel approach for enhancing CAR T cell efficacy in solid tumors and provides proof of principle for site-directed expression of factors that promote effector T cell differentiation.
Project description:The efficacy of Chimeric Antigen Receptor (CAR) T cells against solid tumors is limited by immunosuppressive factors in the tumor microenvironment (TME) including adenosine, which suppresses CAR T cells through activation of the A2A receptor (A2AR). To overcome this, CAR T cells were engineered to express A1 receptor (A1R), a receptor that signals inversely to A2AR. Using murine and human CAR T cells, constitutive A1R overexpression was demonstrated to significantly enhance CAR T cell effector function albeit at the expense of CAR T cell persistence. Through a novel CRISPR/Cas9 “knock-in” approach we demonstrated that CAR T cells engineered to express A1R in a tumor-localized manner, led to enhanced anti-tumor efficacy dependent on the transcription factor IRF8 and was transcriptionally unique when compared to A2AR deletion. This data provides a novel approach for enhancing CAR T cell efficacy in solid tumors and provides proof of principle for site-directed expression of factors that promote effector T cell differentiation.
Project description:The efficacy of Chimeric Antigen Receptor (CAR) T cells against solid tumors is limited by immunosuppressive factors in the tumor microenvironment (TME) including adenosine, which suppresses CAR T cells through activation of the A2A receptor (A2AR). To overcome this, CAR T cells were engineered to express A1 receptor (A1R), a receptor that signals inversely to A2AR. Using murine and human CAR T cells, constitutive A1R overexpression was demonstrated to significantly enhance CAR T cell effector function albeit at the expense of CAR T cell persistence. Through a novel CRISPR/Cas9 “knock-in” approach we demonstrated that CAR T cells engineered to express A1R in a tumor-localized manner, led to enhanced anti-tumor efficacy dependent on the transcription factor IRF8 and was transcriptionally unique when compared to A2AR deletion. This data provides a novel approach for enhancing CAR T cell efficacy in solid tumors and provides proof of principle for site-directed expression of factors that promote effector T cell differentiation.
Project description:The efficacy of Chimeric Antigen Receptor (CAR) T cells against solid tumors is limited by immunosuppressive factors in the tumor microenvironment (TME) including adenosine, which suppresses CAR T cells through activation of the A2A receptor (A2AR). To overcome this, CAR T cells were engineered to express A1 receptor (A1R), a receptor that signals inversely to A2AR. Using murine and human CAR T cells, constitutive A1R overexpression was demonstrated to significantly enhance CAR T cell effector function albeit at the expense of CAR T cell persistence. Through a novel CRISPR/Cas9 “knock-in” approach we demonstrated that CAR T cells engineered to express A1R in a tumor-localized manner, led to enhanced anti-tumor efficacy dependent on the transcription factor IRF8 and was transcriptionally unique when compared to A2AR deletion. This data provides a novel approach for enhancing CAR T cell efficacy in solid tumors and provides proof of principle for site-directed expression of factors that promote effector T cell differentiation.
Project description:Regulatory T cells (Tregs) are promising cellular therapies to induce immune tolerance in organ transplantation and autoimmune disease. The success of chimeric antigen receptor (CAR) T-cell therapy for cancer has sparked interest in using CARs to generate antigen-specific Tregs. Here, we compared CAR with endogenous T cell receptor (TCR)/CD28 activation in human Tregs. Strikingly, CAR Tregs displayed increased cytotoxicity and diminished suppression of antigen-presenting cells and effector T (Teff) cells compared with TCR/CD28 activated Tregs. RNA sequencing revealed that CAR Tregs activate Teff cell gene programs. Indeed, CAR Tregs secreted high levels of inflammatory cytokines, with a subset of FOXP3+ CAR Tregs uniquely acquiring CD40L surface expression and producing IFNγ. Interestingly, decreasing CAR antigen affinity reduced Teff cell gene expression and inflammatory cytokine production by CAR Tregs. Our findings showcase the impact of engineered receptor activation on Treg biology and support tailoring CAR constructs to Tregs for maximal therapeutic efficacy.
Project description:Chimeric antigen receptor (CAR)-T cell therapy targeting human CD19 have demonstrated clinical efficacy against B-cell malignancies. However, CAR-T cell therapy's efficacy against solid tumors is limited due to factors like low tumor-associated antigens, infiltration rate, and T cell exhaustion. We have shown that deleting NR4a genes in CAR-T cells prevents T cell exhaustion and improved their therapeutic effects on solid tumors in a mouse model. To further explore this for human, we deleted all three NR4a family factors in CAR-T cells that recognize Epidermal Growth Factor Receptor type 2 (HER2) using the CRISPR/Cas9 system. These modified CAR-T cells (NR4a-TKO CAR-T) exhibited resistance to exhaustion, increased tumor-killing activity, and higher efficacy in tumor regression and survival rate in a human lung carcinoma model in mice. The enhanced therapeutic effects were associated with increased cytokine expression, reduced exhaustion-related gene expression, and improved persistence within tumors. We propose that targeting NR4a could be a promising strategy for developing superior CAR-T cells against solid tumors.