Placental T cells retain enhanced stemness and altered cytokine response favoring durable efficacy of CD19 CAR-T
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ABSTRACT: We explored transcriptional profile of CD19 CAR-T cells generated from different starting material source (placenta vs. adult peripheral blood) with same protocol and transduced with same CAR construct
Project description:We have compared a low-affinity second-generation anti-CD19 CAR (CAT) with the high-affinity FMC63 CAR used in tisagenlecleucel to understand the unknown molecular mechanisms that drive different CAR T cell treatment outcomes. CAT cells are characterized by a faster antigen dissociation rate and present an enhanced in vivo expansion and anti-tumor efficacy, showing lower toxicity to patients and a long-term persistence in a Phase I clinical study. To understand this improved CAT cells behaviour, we performed a systematic in vitro characterization of the transcriptomic (RNA-seq) and protein (CyTOF) changes between the two groups. The analysis focused on T cells expressing low-affinity vs high-affinity anti-CD19 CARs following stimulation with CD19-expressing cells. Our results show that CAT potent and long-term anti-tumour responses may be sustained by the establishment of a CAR T cells self-reinforcing circuit activated through cytokines polyfunctional crosstalk. This study may inform the design of versatile CAR T cells, capable of balancing safety and efficacy.
Project description:Chimeric antigen receptor T cell (CAR-T) targeting the CD19 antigen represents an innovative therapeutic approach to improve the outcome of relapsed or refractory B-cell acute lymphoblastic leukemia (B-ALL). Yet, despite a high initial remission rate, CAR-T therapy ultimately fails for some patients. Notably, around half of relapsing patients develop CD19 negative (CD19neg) B-ALL allowing leukemic cells to evade CD19-targeted therapy. Herein, we investigate leukemic cells of a relapsing B-ALL patient, at two-time points: before (T1) and after (T2) anti-CD19 CAR-T treatment. We show that at T2, the B-ALL relapse is CD19 negative due to the expression of a non-functional CD19 transcript retaining intron 2. Then, using single-cell RNA sequencing (scRNAseq) approach, we demonstrate that CD19neg leukemic cells were present before CAR-T cell therapy and thus that the relapse results from the selection of these rare CD19neg B-ALL clones. In conclusion, our study shows that scRNAseq profiling can reveal pre-existing CD19neg subclones, raising the possibility to assess the risk of targeted therapy failure.
Project description:Recent improvements in relapse/refractory B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) outcome can be attributed, in part, to the emergence of CD19-directed immune-based therapies including chimeric antigen receptor (CAR)-T cell therapy and bi-specific T cell engager (BiTE) therapy. Longitudinal BCP-ALL studies have highlighted individual cases of progressive surface CD19 antigen reduction associated with disease persistence following CAR-T infusion. CD19 genomic deletions and mRNA alternative splicing have been previously shown to confer CAR-T and BiTE resistance, however gene regulatory programs that modulate BCP-ALL CD19 surface antigen abundance remains poorly understood. To address this, we performed genome-wide CRISPR/Cas9 screening to identify positive and negative regulators of surface CD19 abundance in human BCP-ALL as compared to mature B cell neoplasms, chronic lymphocytic leukemia and B cell lymphoma. Here, we show DNA binding protein, ZNF143, occupies the CD19 promoter and transcriptionally regulates CD19 mRNA expression in human B-cell malignancies. Conversely, we show that RNA-binding protein, NUDT21, limits surface CD19 abundance on BCP-ALL. NUDT21 acts to regulate CD19 3’ UTR length and CD19 mRNA stability. NUDT21 mRNA displays high concordance with CD19 mRNA expression in primary healthy and transformed human B cell progenitors. Using primary BCP-ALL patient single cell data, we show that reduction of CD19 mRNA expression following CAR-T therapy coincides with increased NUDT21 mRNA expression. Importantly, NUDT21 ablation sensitizes BCP-ALL to BiTE and CD19 CAR-T killing ex vivo. These findings reveal previously unknown modulators of CD19 antigen abundance that can be applied to therapeutically enhance or determine resistance to CD19-based therapies in B-cell leukemias.
Project description:CAR T-cell therapy has led to tremendous successes in the treatment of B-cell malignancies. However, 30%-50% of treated patients relapse – often with reduced target antigen expression. We report that anti-CD19 CAR T-cells cause a rapid reduction of CD19 expression within hours in CAR-T exposed CD19+ B-ALL cells. Initially, anti-CD19 CAR T-cells cause CD19 clusters at the T-cell – leukemia cell interface followed by CD19 internalization and decreased CD19 surface expression. Subsequently, CD19 expression is repressed by transcriptional rewiring. Using single-cell RNA-seq and single-cell ATAC-seq we demonstrate that a subset of CD19low cells that are refractory to CAR T-cell killing employ transcriptional programs of physiological B-cell activation and germinal center reaction in order to sustain decreased CD19 expression. Inhibiting B-cell activation programs with the BTK inhibitor ibrutinib increased the cytotoxic efficacy of anti-CD19 CAR T-cells without effecting CAR T-cell viability. These results demonstrate transcriptional plasticity as an underlying mechanism of CAR T-resistance and highlight the importance of combining CAR T-cell therapy with targeted therapies that aim to overcome this plasticity.
Project description:Recent improvements in relapse/refractory B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) outcome can be attributed, in part, to the emergence of CD19-directed immune-based therapies including chimeric antigen receptor (CAR)-T cell therapy and bi-specific T cell engager (BiTE) therapy. Longitudinal BCP-ALL studies have highlighted individual cases of progressive surface CD19 antigen reduction associated with disease persistence following CAR-T infusion. CD19 genomic deletions and mRNA alternative splicing have been previously shown to confer CAR-T and BiTE resistance, however gene regulatory programs that modulate BCP-ALL CD19 surface antigen abundance remains poorly understood. To address this, we performed genome-wide CRISPR/Cas9 screening to identify positive and negative regulators of surface CD19 abundance in human BCP-ALL as compared to mature B cell neoplasms, chronic lymphocytic leukemia and B cell lymphoma. Here, we show DNA binding protein, ZNF143, occupies the CD19 promoter and transcriptionally regulates CD19 mRNA expression in human B-cell malignancies. Conversely, we show that RNA-binding protein, NUDT21, limits surface CD19 abundance on BCP-ALL. NUDT21 acts to regulate CD19 3’ UTR length and CD19 mRNA stability. NUDT21 mRNA displays high concordance with CD19 mRNA expression in primary healthy and transformed human B cell progenitors. Using primary BCP-ALL patient single cell data, we show that reduction of CD19 mRNA expression following CAR-T therapy coincides with increased NUDT21 mRNA expression. Importantly, NUDT21 ablation sensitizes BCP-ALL to BiTE and CD19 CAR-T killing ex vivo. These findings reveal previously unknown modulators of CD19 antigen abundance that can be applied to therapeutically enhance or determine resistance to CD19-based therapies in B-cell leukemias.
Project description:Recent improvements in relapse/refractory B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) outcome can be attributed, in part, to the emergence of CD19-directed immune-based therapies including chimeric antigen receptor (CAR)-T cell therapy and bi-specific T cell engager (BiTE) therapy. Longitudinal BCP-ALL studies have highlighted individual cases of progressive surface CD19 antigen reduction associated with disease persistence following CAR-T infusion. CD19 genomic deletions and mRNA alternative splicing have been previously shown to confer CAR-T and BiTE resistance, however gene regulatory programs that modulate BCP-ALL CD19 surface antigen abundance remains poorly understood. To address this, we performed genome-wide CRISPR/Cas9 screening to identify positive and negative regulators of surface CD19 abundance in human BCP-ALL as compared to mature B cell neoplasms, chronic lymphocytic leukemia and B cell lymphoma. Here, we show DNA binding protein, ZNF143, occupies the CD19 promoter and transcriptionally regulates CD19 mRNA expression in human B-cell malignancies. Conversely, we show that RNA-binding protein, NUDT21, limits surface CD19 abundance on BCP-ALL. NUDT21 acts to regulate CD19 3’ UTR length and CD19 mRNA stability. NUDT21 mRNA displays high concordance with CD19 mRNA expression in primary healthy and transformed human B cell progenitors. Using primary BCP-ALL patient single cell data, we show that reduction of CD19 mRNA expression following CAR-T therapy coincides with increased NUDT21 mRNA expression. Importantly, NUDT21 ablation sensitizes BCP-ALL to BiTE and CD19 CAR-T killing ex vivo. These findings reveal previously unknown modulators of CD19 antigen abundance that can be applied to therapeutically enhance or determine resistance to CD19-based therapies in B-cell leukemias.
Project description:Recent improvements in relapse/refractory B-cell progenitor acute lymphoblastic leukemia (BCP-ALL) outcome can be attributed, in part, to the emergence of CD19-directed immune-based therapies including chimeric antigen receptor (CAR)-T cell therapy and bi-specific T cell engager (BiTE) therapy. Longitudinal BCP-ALL studies have highlighted individual cases of progressive surface CD19 antigen reduction associated with disease persistence following CAR-T infusion. CD19 genomic deletions and mRNA alternative splicing have been previously shown to confer CAR-T and BiTE resistance, however gene regulatory programs that modulate BCP-ALL CD19 surface antigen abundance remains poorly understood. To address this, we performed genome-wide CRISPR/Cas9 screening to identify positive and negative regulators of surface CD19 abundance in human BCP-ALL as compared to mature B cell neoplasms, chronic lymphocytic leukemia and B cell lymphoma. Here, we show DNA binding protein, ZNF143, occupies the CD19 promoter and transcriptionally regulates CD19 mRNA expression in human B-cell malignancies. Conversely, we show that RNA-binding protein, NUDT21, limits surface CD19 abundance on BCP-ALL. NUDT21 acts to regulate CD19 3’ UTR length and CD19 mRNA stability. NUDT21 mRNA displays high concordance with CD19 mRNA expression in primary healthy and transformed human B cell progenitors. Using primary BCP-ALL patient single cell data, we show that reduction of CD19 mRNA expression following CAR-T therapy coincides with increased NUDT21 mRNA expression. Importantly, NUDT21 ablation sensitizes BCP-ALL to BiTE and CD19 CAR-T killing ex vivo. These findings reveal previously unknown modulators of CD19 antigen abundance that can be applied to therapeutically enhance or determine resistance to CD19-based therapies in B-cell leukemias.
Project description:Purpose: To compare cell states between CD19-28z and GD2-28z human CAR T cells on day 10 of cell culture. Methods: Human T cells were activated and lentivirally transduced with CD19-28z or GD2-28z CAR constructs and maintained in culture for 10 days, and then delivered to the Stanford Functional Genomics Facility for 3' single-cell RNA-sequencing on the 10X Genomics platform. Results: Comparison of transcription factor profiles by single cell RNA-seq analysis of CD8+ T cells expressing CD19-28z vs. GD2-28z CAR confirmed that the bZIP family members JUN, JUNB, JUND, and ATF4 were among the most differentially expressed and broadly connected in exhausted GD2-28z CAR T cells. Conclusions: This study provides insights into cell states that could explain the underlying differences between highly functional CD19-28z CAR T cells and exhaustion-prone GD2-28z CAR T cells on day 10 in culture.