Project description:Chimeric antigen receptor modified T (CAR-T) cell therapy has limited efficacy against solid tumor, one major challenge is T cell exhaustion. To address this challenge, we performed a candidate gene screen using a hypofunction CAR-T cell model, and found that knocking out BATF improved the performance of CAR-T cells. In different types of CAR-T cells and mouse OT-1 cells, knocking out BATF endows T cells with improved resistance to exhaustion and better tumor eradication efficacy. We find that BATF binds to and up-regulates a subset of exhaustion genes in human CAR-T cells. Furthermore, BATF regulates the expression of genes involved in the development of effector and memory cells, and knocking out BATF shifts the population towards more central memory subset. Therefore, we conclude that BATF is a key factor limiting CAR-T cell function, and its depletion improves CAR-T cells efficacy against solid tumor.
Project description:Cooperative interactions among transcription factors are essential for gene transcription. We previously showed that NFAT and AP-1 (Fos-Jun) transcription factors cooperate to promote the effector functions of T cells, but that under conditions where it is unable to cooperate with AP-1, NFAT imposes a negative feedback programme of T cell hyporesponsiveness (“exhaustion”). Here we show that BATF and IRF4 cooperate to counter T cell exhaustion. Overexpression of Batf in CD8+ 42 T cells expressing a chimeric antigen receptor (CAR) promoted the survival and expansion of tumour-infiltrating CAR T cells, increased their production of effector cytokines, decreased their expression of inhibitory receptors and the exhaustion-associated transcription factor TOX, and led to the generation of long-lived memory T cells that controlled tumour recurrence. These responses were dependent on the BATF-IRF interaction, since cells expressing a Batf mutant unable to interact with Irf4 did not survive in tumours and did not effectively delay tumour growth. We suggest that BATF overexpression is a therapeutically viable option for improving the anti-tumour responses of CAR TILs, by skewing their phenotypes and transcriptional profiles away from exhaustion and towards increased effector function.
Project description:Cooperative interactions among transcription factors are essential for gene transcription. We previously showed that NFAT and AP-1 (Fos-Jun) transcription factors cooperate to promote the effector functions of T cells, but that under conditions where it is unable to cooperate with AP-1, NFAT imposes a negative feedback programme of T cell hyporesponsiveness (“exhaustion”). Here we show that BATF and IRF4 cooperate to counter T cell exhaustion. Overexpression of Batf in CD8+ 42 T cells expressing a chimeric antigen receptor (CAR) promoted the survival and expansion of tumour-infiltrating CAR T cells, increased their production of effector cytokines, decreased their expression of inhibitory receptors and the exhaustion-associated transcription factor TOX, and led to the generation of long-lived memory T cells that controlled tumour recurrence. These responses were dependent on the BATF-IRF interaction, since cells expressing a Batf mutant unable to interact with Irf4 did not survive in tumours and did not effectively delay tumour growth. We suggest that BATF overexpression is a therapeutically viable option for improving the anti-tumour responses of CAR TILs, by skewing their phenotypes and transcriptional profiles away from exhaustion and towards increased effector function.
Project description:Cooperative interactions among transcription factors are essential for gene transcription. We previously showed that NFAT and AP-1 (Fos-Jun) transcription factors cooperate to promote the effector functions of T cells, but that under conditions where it is unable to cooperate with AP-1, NFAT imposes a negative feedback programme of T cell hyporesponsiveness (“exhaustion”). Here we show that BATF and IRF4 cooperate to counter T cell exhaustion. Overexpression of Batf in CD8+ 42 T cells expressing a chimeric antigen receptor (CAR) promoted the survival and expansion of tumour-infiltrating CAR T cells, increased their production of effector cytokines, decreased their expression of inhibitory receptors and the exhaustion-associated transcription factor TOX, and led to the generation of long-lived memory T cells that controlled tumour recurrence. These responses were dependent on the BATF-IRF interaction, since cells expressing a Batf mutant unable to interact with Irf4 did not survive in tumours and did not effectively delay tumour growth. We suggest that BATF overexpression is a therapeutically viable option for improving the anti-tumour responses of CAR TILs, by skewing their phenotypes and transcriptional profiles away from exhaustion and towards increased effector function.
Project description:Adoptive T cell therapy with gene-modified T cells expressing chimeric antigen receptor (CAR) is a rapidly growing field of translational medicine and recently has shown dramatic therapeutic success in the treatment of B-cell malignancies. However, challenges to achieve similar response in patients harboring solid tumour are still considerable. To achieve anti-tumor efficacy, these cells must survive, expand and persist after infusion into patients. An important lesson has been derived from clinical trials using CAR technologies: the relevance of the CAR design to enhance signaling and sustain T cell proliferation and survival. Here, we prove that third generation CARs specific for GD2 antigen incorporating CD28.4-1BB costimulatory domains improves T cell immunotherapy in a neuroblastoma (NB) pre-clinical model, as compared to a CAR with the same specificity but including CD28.OX40 costimulation. Indeed, we test the anti-tumor activity of polyclonal T cells genetically modified with third generation CAR.GD2 incorporating either CD28.4-1BB or CD28.OX40 in frame with the safety switch inducible Caspase 9 (iC9). We prove a significant in vitro and in vivo amelioration of the approach by the presence of 4.1BB signaling in terms of: 1) less T cell exhaustion, 2) lower basal T cell activation, 3) higher in vivo tumor control and 4) T cell persistence. In addition, the fine tuning of T cell culture conditions with the use of IL7 and IL15 show to be synergic with the third generation CAR.GD2 design to optimize CAR T immunotherapy for NB. Our results provide a proof-of-concept for the need to optimize not only CAR construct design but also T cell culture conditions in order to boost T cell activity in vivo.
Project description:Dysfunction in T cells limits the efficacy of cancer immunotherapy. We profiled the epigenome, transcriptome, and enhancer connectome of exhaustion-prone GD2-targeting HA-28z chimeric antigen receptor (CAR) T cells and control CD19-targeting CAR T cells, which present less exhaustion-inducing tonic signaling, at multiple points during their ex vivo expansion. We found widespread, dynamic changes in chromatin accessibility and 3D chromosome conformation preceding changes in gene expression, notably at loci proximal to exhaustion-associated genes such as PDCD1, CTLA4, and HAVCR2, and increased DNA motif access for AP-1 family transcription factors, which are known to promote exhaustion. Although T cell exhaustion has been studied in detail in mouse, we find that the regulatory networks of T cell exhaustion differ between the species and involve distinct loci of accessible chromatin and cis-regulated target genes in human CAR T cell exhaustion. Deletion of exhaustion-specific candidate enhancers of PDCD1 suppress the expression of PD-1 in an in vitro model of T cell dysfunction and in HA-28z CAR T cells, suggesting enhancer editing as a path forward in improving cancer immunotherapy.
Project description:Dysfunction in T cells limits the efficacy of cancer immunotherapy. We profiled the epigenome, transcriptome, and enhancer connectome of exhaustion-prone GD2-targeting HA-28z chimeric antigen receptor (CAR) T cells and control CD19-targeting CAR T cells, which present less exhaustion-inducing tonic signaling, at multiple points during their ex vivo expansion. We found widespread, dynamic changes in chromatin accessibility and 3D chromosome conformation preceding changes in gene expression, notably at loci proximal to exhaustion-associated genes such as PDCD1, CTLA4, and HAVCR2, and increased DNA motif access for AP-1 family transcription factors, which are known to promote exhaustion. Although T cell exhaustion has been studied in detail in mouse, we find that the regulatory networks of T cell exhaustion differ between the species and involve distinct loci of accessible chromatin and cis-regulated target genes in human CAR T cell exhaustion. Deletion of exhaustion-specific candidate enhancers of PDCD1 suppress the expression of PD-1 in an in vitro model of T cell dysfunction and in HA-28z CAR T cells, suggesting enhancer editing as a path forward in improving cancer immunotherapy.
Project description:Chimeric antigen receptor (CAR)-expressing T-cells induce durable remissions in patients with relapsed/refractory B-cell malignancies. CARs are artificial constructs introduced into mature T-cells conferring a second, non-MHC restricted specificity in addition to the endogenous T-cell receptor (TCR). The impact of TCR activation on CAR T-cell efficacy in vivo has important implications for clinical optimization of CAR T-cell therapy, but cannot be systematically evaluated in xenograft models. Using an immunocompetent, syngeneic murine model of CD19-targeted CAR T-cell therapy for pre-B cell ALL, we demonstrate loss of CD8 CAR T-cell mediated clearance of leukemia associated with T-cell exhaustion and apoptosis when TCR antigen is present. CD4 CAR T-cells demonstrate equivalent cytotoxicity, as compared to CD8 CAR T-cells, and in contrast, retain in vivo efficacy in the presence of TCR stimulation. Gene expression profiles confirm increased exhaustion and apoptosis of CAR8 upon dual receptor stimulation compared to CAR4, and indicate inherent differences in T-cell pathways. Chimeric antigen receptor (CAR) T cells express two activating receptors, the CAR and the endogenous T cell receptor (TCR). CAR T cells can be derived from either CD8 or CD4 T cells to generate CAR8 and CAR4 cells, respectively. In vivo, CAR8 and CAR4 cells respond differently when simultaneously stimulated through the CAR and TCR.
Project description:Chimeric antigen receptor (CAR) T-cells have not induced meaningful clinical responses in solid tumor indications. Loss of T-cell stemness, poor expansion capacity and exhaustion during prolonged tumor antigen exposure are major causes of CAR T-cell therapeutic resistance. scRNA-sequencing analysis of CAR T-cells from a first-in-human trial in metastatic prostate cancer identified two distinct and independently validated cell states associated with antitumor potency or lack of efficacy. Low levels of the PRDM1 gene encoding the BLIMP1 transcription factor defined highly potent TCF7+CD8+ CAR T-cells, while enrichment of TIM3+CD8+ T-cells with elevated PRDM1 expression predicted poor outcome. PRDM1 single knockout promoted TCF7-dependent CAR T-cell stemness and proliferation resulting in marginally enhanced leukemia control. However, in the setting of PRDM1 deficiency, a negative epigenetic feedback program of NFAT-driven T-cell dysfunction characterized by compensatory upregulation of NR4A3 and multiple other genes encoding exhaustion-related transcription factors hampered effector function in solid tumors. PRDM1 and NR4A3 combined ablation skewed CAR T-cell phenotypes away from TIM3+CD8+ and toward TCF7+CD8+ to counter exhaustion of tumor-infiltrating CAR T-cells and improve in vivo antitumor responses, effects that were not achieved with BLIMP1 or NR4A3 single disruption alone. These data reveal a novel molecular targeting strategy to enrich stem-like CAR T-cells resistant to exhaustion and underscore dual inhibition of PRDM1/NR4A3 expression or activity as a promising approach to advance adoptive cell immuno-oncotherapy.