Project description:Cell–cell interactions (CCIs) are essential for tissue functionality and targeted therapies, particularly in the context of chimeric antigen receptor T (CAR T) cells. Here, we introduce TyP-HIM-seq, a barcoding approach based on tyrosinase-catalyzed proximity (TyP) labeling. This method enables the simultaneous high-throughput measurement of interacting cells and their mRNA expressions through single-cell sequencing. By translating intercellular contact into in situ chemical labeling of a DNA barcode, TyP-HIM-seq allows for a comprehensive assessment of CCIs and full deconvolution of related molecular pathways. We used TyP-HIM-seq to investigate the CCIs between CD19 CAR-Jurkat cells and Ramos tumor cells.
Project description:Chimeric antigen receptor T-cell (CAR-T) therapy is at the forefront of cell immunotherapy. In this study, we generated an anti-CD19 CAR-Jurkat T cell line using a locally produced second-generation CD19 CAR construct, enabling us to analyze early proteomic changes crucial for understanding the signaling pathways and mechanisms of action of this CAR-T cell. SILAC-heavy tagged RAJI B-cells and anti-CD19 CAR-Jurkat T-cells were co-cultured for ten minutes. The proteomic profiles were obtained via DIA methodology on the Orbitrap Astral LC-MS/MS platform. The proteome was extensively covered, resulting in approximately 8800 protein identifications at 1% FDR. The effector CAR-Jurkat cells showed proteomic changes involving antigen presentation by CD74. The target RAJI B-cells exhibited more significant alterations, such as CD28, essential for T-cell survival and activation.
Project description:TNFRSF17 in Ramos tumor cells has been found to affect their interaction with CD19 CAR T cells. We used RNA sequencing to compare the transcriptomic profiles between TNFRSF17 knockdown Ramos cells and unperturbed control cells.
Project description:Adoptive cell therapy, a subset of cancer immunotherapy, is collection of therapeutic approaches which aim to redirect the immune system by reprogramming patient T-cells to target antigenic molecules differentially and specifically expressed in certain cancers. One promising immunotherapy technique is CAR T-cell therapy, where cancer cells are targeted through the expression a chimeric antigen receptor (CAR), a synthetic trans- membrane receptor that functionally compensates for the T-cell receptor (TCR) but targets a tumor associated antigen on the cancer cell surface. While CAR T-cell therapy is promising with two clinically approved second-generation CARs (Kymriah and Yescarta), few studies have investigated the mechanism of signal propagation in T-cells and no studies have investigated the potential signaling response in the target cells. To gain further insight to CAR-based signaling, we stimulated third generation CD19 CAR-expressing Jurkat T-cells by co-culture with SILAC labeled CD19HI Raji B-cells and used two phosphoenrichment strategies coupled with liquid chromatography-tandem mass spec- trometry (LC-MS/MS) to detect and analyze global phosphorylation changes in both cell populations. Analysis of the phosphopeptides originating from the CD19-CAR T cells revealed an increase in many phosphorylation events necessary for canonical TCR signaling. We also observed for the first time a significant decrease in B-cell receptor- related phosphopeptide abundance in CD19HI Raji B-cells after co-culture with CD19-targetted CAR T-cells.
Project description:To characterize transfer of molecules from target cells into CAR T cells via trogocytosis we cultured NALM-6 leukemia cell line expressing a CD19-mCherry fusion protein with CAR T cells. NALM6-CD19-mCherry were loaded with heavy amino acid and cocultured with CAR T cells for 1 hour. CAR T cells were next sorted into two fractions, mCherry-positive (TrogPos), and -negative (TrogNeg). Proteomics analysis revealed the presence of targeted antigen (CD19) in the TrogPos only.
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: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:Long-lived, self-renewing, multipotent T memory stem cells (TSCM) can trigger profound and sustained tumor regression but their rareness poses a major hurdle to their clinical application. Presently, clinically compliant procedures to generate relevant numbers of this T cell population are undefined. Here, we provide a strategy for deriving large numbers of clinical grade tumor-redirected TSCM cells starting from naïve precursors. CD8+CD62L+CD45RA+ naïve T cells enriched by streptamer-based serial positive selection were activated by CD3/CD28 engagement in the presence of IL-7, IL-21 and the glycogen synthase-3β inhibitor TWS119, and genetically engineered to express a CD19-specific chimeric antigen receptor (CD19-CAR). These conditions allowed for the generation of CD19-CAR modified TSCM cells that were phenotypically, functionally and transcriptomically equivalent to their naturally occurring counterpart. Compared with T cell products currently under clinical investigation, CD19-CAR modified TSCM cells exhibit enhanced metabolic fitness, persistence and anti-tumor activity against systemic acute lymphoblastic leukemia xenografts. Based on these findings, we have initiated a phase 1 clinical study to evaluate the activity of CD19-CAR modified TSCM in patients with B-cell malignancies refractory to prior allogeneic hematopoietic stem cell transplantation. Three healthy human blood donors provided lymphocyte-enriched apheresis blood for this study after informed consent. From all samples, total RNA was isolated using an miRNeasy Mini Kit (Qiagen), processed by Ambionâ??s WT expression kit, fragmented and labeled with a WT Terminal Labeling Kit (Affymetrix), hybridized to WT Human Gene 1.0 ST arrays (Affymetrix) and stained on a Genechip Fluidics Station 450 (Affymetrix), all according to the respective manufacturer's instructions. Samples represent exon-level and gene-level analyses.
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.