Project description:Human primary CD3+ T cells expressing IL13Ra2-targeted chimeric antigen receptors (CARs) that had been identified through high throughput pooled screening were rechallenged with an IL13Ra2+ human glioblastoma cell line , then stained with CITESEQ antibodies indicative of T cell memory and exhaustion state and prepared for single cell sequencing in order to determine their phenotypic responses to chronic tumor challenge relative to that of a clinical standard CAR.
Project description:Due to the low-throughput process of systematically designing and functionally testing chimeric antigen receptors (CARs), only a small set of immune signaling domains have been thoroughly explored, despite their major role in T cell activation, effector function and persistence. SpeedingCARs presents an integrated method for engineering CAR T cells by signaling domain shuffling and functional screening by single-cell sequencing. Leveraging the inherent modularity of natural signaling domains, we generated a diverse library of 180 unique CAR variants, which were genomically integrated into primary human T cells by CRISPR-Cas9. Functional and pooled screening of the CAR T cell library was performed by co-culture with tumor cells, followed by single-cell RNA sequencing (scRNA-seq) and single-cell CAR sequencing (scCAR-seq), thus enabling high-throughput profiling of multi-dimensional cellular responses.
Project description:Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, containing self-renewing stem-like GBM stem cells (GSCs) that have been a focus of immunotherapies. Chimeric antigen receptor (CAR) T cell therapy has shown evidence of clinical activity, but overall limited responses in patients with GBMs. Here, we interrogated molecular determinants of CAR T cell-mediated GBM killing through whole-genome CRISPR screens in both CAR T cells and patient-derived GSCs. CRISPR screening of CAR T cells identified dependencies for their effector functions, including TLE4 and IKZF2. Targeted knockout of these genes in CAR T cells robustly enhanced antitumor efficacy against GBM patient-derived xenografts (PDXs). Bulk and single cell-RNA sequencing of edited CAR T cells revealed transcriptional profiles of superior effector function and inhibited exhaustion responses. Reciprocal screening of GSCs identified genes essential for their susceptibility to CAR-mediated killing, including RELA and NPLOC4, the knockout of which altered the tumor-immune signaling axis and increased responsiveness of CAR therapy. Overall, CRISPR screening of CAR T cells and GSCs are promising strategies to discover avenues and inform potential combinatorial approaches for enhancing CAR T cell therapeutic efficacy against GBM, and can be extended to reveal key mediators of immunotherapy responses across solid tumors.
Project description:Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, containing self-renewing stem-like GBM stem cells (GSCs) that have been a focus of immunotherapies. Chimeric antigen receptor (CAR) T cell therapy has shown evidence of clinical activity, but overall limited responses in patients with GBMs. Here, we interrogated molecular determinants of CAR T cell-mediated GBM killing through whole-genome CRISPR screens in both CAR T cells and patient-derived GSCs. CRISPR screening of CAR T cells identified dependencies for their effector functions, including TLE4 and IKZF2. Targeted knockout of these genes in CAR T cells robustly enhanced antitumor efficacy against GBM patient-derived xenografts (PDXs). Bulk and single cell-RNA sequencing of edited CAR T cells revealed transcriptional profiles of superior effector function and inhibited exhaustion responses. Reciprocal screening of GSCs identified genes essential for their susceptibility to CAR-mediated killing, including RELA and NPLOC4, the knockout of which altered the tumor-immune signaling axis and increased responsiveness of CAR therapy. Overall, CRISPR screening of CAR T cells and GSCs are promising strategies to discover avenues and inform potential combinatorial approaches for enhancing CAR T cell therapeutic efficacy against GBM, and can be extended to reveal key mediators of immunotherapy responses across solid tumors.
Project description:Glioblastoma (GBM) is the most prevalent primary malignant brain tumor, containing self-renewing stem-like GBM stem cells (GSCs) that have been a focus of immunotherapies. Chimeric antigen receptor (CAR) T cell therapy has shown evidence of clinical activity, but overall limited responses in patients with GBMs. Here, we interrogated molecular determinants of CAR T cell-mediated GBM killing through whole-genome CRISPR screens in both CAR T cells and patient-derived GSCs. CRISPR screening of CAR T cells identified dependencies for their effector functions, including TLE4 and IKZF2. Targeted knockout of these genes in CAR T cells robustly enhanced antitumor efficacy against GBM patient-derived xenografts (PDXs). Bulk and single cell-RNA sequencing of edited CAR T cells revealed transcriptional profiles of superior effector function and inhibited exhaustion responses. Reciprocal screening of GSCs identified genes essential for their susceptibility to CAR-mediated killing, including RELA and NPLOC4, the knockout of which altered the tumor-immune signaling axis and increased responsiveness of CAR therapy. Overall, CRISPR screening of CAR T cells and GSCs are promising strategies to discover avenues and inform potential combinatorial approaches for enhancing CAR T cell therapeutic efficacy against GBM, and can be extended to reveal key mediators of immunotherapy responses across solid tumors.
Project description:Chronic stimulation can cause T cell dysfunction and limit efficacy of cellular immunotherapies. CRISPR screens have nominated gene targets for engineered T cells, but improved methods are required to compare large numbers of synthetic knockin sequences to reprogram cell functions. Here, we developed Modular Pooled Knockin Screening (ModPoKI), an adaptable platform for modular construction of DNA knockin libraries using barcoded multicistronic adaptors. We built two ModPoKI libraries of 100 transcription factors (TFs) and 129 natural and synthetic surface receptors. Over 30 ModPoKI screens across human TCR and CAR T cells in diverse conditions identified a transcription factor AP4 (TFAP4) construct that enhanced fitness of chronically-stimulated CAR T cells and anti-cancer function in vitro and in vivo. ModPoKI’s modularity allowed us to generate a ~10,000-member library of TF combinations. Non-viral knockin of a combined BATF-TFAP4 polycistronic construct further enhanced function. ModPoKI facilitates discovery of complex gene constructs to program cellular functions.
Project description:Chronic stimulation can cause T cell dysfunction and limit efficacy of cellular immunotherapies. CRISPR screens have nominated gene targets for engineered T cells, but improved methods are required to compare large numbers of synthetic knockin sequences to reprogram cell functions. Here, we developed Modular Pooled Knockin Screening (ModPoKI), an adaptable platform for modular construction of DNA knockin libraries using barcoded multicistronic adaptors. We built two ModPoKI libraries of 100 transcription factors (TFs) and 129 natural and synthetic surface receptors. Over 30 ModPoKI screens across human TCR and CAR T cells in diverse conditions identified a transcription factor AP4 (TFAP4) construct that enhanced fitness of chronically-stimulated CAR T cells and anti-cancer function in vitro and in vivo. ModPoKI’s modularity allowed us to generate a ~10,000-member library of TF combinations. Non-viral knockin of a combined BATF-TFAP4 polycistronic construct further enhanced function. ModPoKI facilitates discovery of complex gene constructs to program cellular functions.
Project description:Chronic stimulation can cause T cell dysfunction and limit efficacy of cellular immunotherapies. CRISPR screens have nominated gene targets for engineered T cells, but improved methods are required to compare large numbers of synthetic knockin sequences to reprogram cell functions. Here, we developed Modular Pooled Knockin Screening (ModPoKI), an adaptable platform for modular construction of DNA knockin libraries using barcoded multicistronic adaptors. We built two ModPoKI libraries of 100 transcription factors (TFs) and 129 natural and synthetic surface receptors. Over 30 ModPoKI screens across human TCR and CAR T cells in diverse conditions identified a transcription factor AP4 (TFAP4) construct that enhanced fitness of chronically-stimulated CAR T cells and anti-cancer function in vitro and in vivo. ModPoKI’s modularity allowed us to generate a ~10,000-member library of TF combinations. Non-viral knockin of a combined BATF-TFAP4 polycistronic construct further enhanced function. ModPoKI facilitates discovery of complex gene constructs to program cellular functions.
Project description:Chronic stimulation can cause T cell dysfunction and limit efficacy of cellular immunotherapies. CRISPR screens have nominated gene targets for engineered T cells, but improved methods are required to compare large numbers of synthetic knockin sequences to reprogram cell functions. Here, we developed Modular Pooled Knockin Screening (ModPoKI), an adaptable platform for modular construction of DNA knockin libraries using barcoded multicistronic adaptors. We built two ModPoKI libraries of 100 transcription factors (TFs) and 129 natural and synthetic surface receptors. Over 30 ModPoKI screens across human TCR and CAR T cells in diverse conditions identified a transcription factor AP4 (TFAP4) construct that enhanced fitness of chronically-stimulated CAR T cells and anti-cancer function in vitro and in vivo. ModPoKI’s modularity allowed us to generate a ~10,000-member library of TF combinations. Non-viral knockin of a combined BATF-TFAP4 polycistronic construct further enhanced function. ModPoKI facilitates discovery of complex gene constructs to program cellular functions.