Acetylcyssteine synergizes PD-1 blockers against colorectal cancer progression by promoting TCF1+PD1+CD8+ T cell differentiation in mice
Ontology highlight
ABSTRACT: PD-1 blockade is important in treating progressive colorectal cancer (CRC). However, some patients with CRC have a poor or no response to immunotherapy. An important reason for this problem is the exhaustion of CD8+ T cells in the tumor microenvironment. Acetylcysteine (NAC) can reduce CD8+ T cell exhaustion in vitro and induce their differentiation into long-lasting phenotypes, thus enhancing the anti-tumor effect of adoptive T cell transfer. However, whether NAC can be combined with PD-1 blockade in CRC treatment and how NAC regulates CD8+ T cell differentiation remains unclear. We constructed a mouse CRC model to study the effect of NAC on tumors. The effect of NAC on CD8+ T cell differentiation and its potential mechanism were explored by cell flow assay and other studies in vitro and ex vivo. We demonstrated that NAC synergized PD-1 antibodies to inhibit CRC progression in a mouse CRC model, mediated by CD8+ T cells. NAC induces TCF1+PD1+CD8+ T cell differentiation and reduces the formation of exhausted T cells (Tex). Moreover, NAC enhanced the expression of Glut4 in CD8+ T cells, promoting the differentiation of TCF1+PD1+CD8+ T cells. Our study provides a novel idea for immunotherapy of clinically progressive CRC and suggests that Glut4 may be a new immunometabolic molecular target for regulating CD8+ T cell differentiation.
Project description:PD-1 blockade therapy, harnessing the cytotoxic potential of CD8+ T cells, has yielded clinical success in treating malignancies. However, its efficacy is often limited due to the progressive differentiation of intratumoral CD8+ T cells into a hypofunctional state known as terminal exhaustion. Despite identifying CD8+ T cell subsets associated with immunotherapy resistance, the molecular pathway triggering the resistance remains elusive. Given the clear association of CD38 with CD8+ T cell subsets resistant to anti-PD1 therapy, we investigated its role in inducing resistance. Phenotypic and functional characterization, along with single-cell RNA sequencing analysis of both in vitro chronically stimulated and intratumoral CD8+ T cells, revealed that CD38-expressing CD8+ T cells are terminally exhausted. Exploring the molecular mechanism, we discovered that CD38 expression was crucial in promoting terminal differentiation of CD8+ T cells by suppressing TCF1 expression, thereby rendering them unresponsive to anti-PD1 therapy. Genetic ablation of CD38 in tumor reactive CD8+ T cells restored TCF1 levels and improved the responsiveness to anti-PD1 therapy in mice. Mechanistically, CD38 expression on exhausted CD8+ T cells elevated intracellular Ca2+ levels through RyR2 calcium channel activation. This, in turn, promoted chronic AKT activation, leading to TCF1 loss. Knockdown of RyR2 or inhibition of AKT in CD8+ T cells maintained TCF1 levels, induced a sustained anti-tumor response, and enhanced responsiveness to anti-PD1 therapy. Thus, targeting CD38 represents a potential strategy to improve the efficacy of anti-PD1 treatment in cancer.
Project description:CD8+ T cells isolated from HCC tissue were divided into three groups: PD1-TIM3- CD8+ TILs, exhibiting full effector function; PD1-intTIM3+ CD8+ TILs, exhibiting partial exhaustion; and PD1-hiTIM3+ CD8+ TILs, exhibiting severe exhaustion, as reflected by the differences in their ability to produce effector cytokines respectively. Transcriptome sequence analysis was performed to investigate the gene expression profile was performed.
Project description:Chronic viral infections are characterized by a state of CD8 T cell dysfunction termed exhaustion. A better understanding of the mechanisms that regulate CD8 T cell responses during chronic infection is required to improve immunotherapies that restore function in exhausted CD8 T cells. Here we identify a novel population of virus-specific CD8 T cells with a T follicular helper (Tfh)-like signature in mice chronically infected with lymphocytic choriomeningitis virus (LCMV). These Tfh-like CD8 T cells expressed the programmed cell death-1 (PD-1) inhibitory receptor but at the same time also expressed co-stimulatory molecules and had a gene signature that was related to CD8 T cell memory precursor cells and hematopoietic stem cells (HSC). These Tfh-like CD8 T cells acted as stem cells during chronic infection undergoing self-renewal and also differentiating into the terminally exhausted CD8 T cells that were present in both lymphoid and non-lymphoid tissues. The Tfh-like CD8 T cells were found only in lymphoid tissues and resided predominantly in the T cell zones along with naïve CD8 T cells. Interestingly, the proliferative burst after PD-1 blockade came almost exclusively from this Tfh-like CD8 T cell subset. Importantly, the transcription factor TCF1 played a cell intrinsic and essential role in the generation of Tfh-like CD8 T cells. Taken together, our study identifies Tfh-like CD8 T cells as the critical subset for maintaining the pool of virus-specific CD8 T cells during chronic infection and as the cells that proliferate after PD-1 blockade. These findings provide a better understanding of T cell exhaustion and have implications towards optimizing PD-1 directed immunotherapy. 8 samples isolated from CD8 T-cells in LCMV clone 13 GK1.5 infected mice (2 naïve, 3 CXCR5+Tim3-, 3 CXCR5-Tim3+) cells were analyzed
Project description:Lymphocytic choriomeningitis virus (LCMV) is the prototypic arenavirus and a natural mouse pathogen. LCMV Armstrong, an acutely resolved strain, and LCMV Clone 13, a mutant that establishes chronic infection, have provided contrasting infection models that continue to inform the fundamental biology of T cell differentiation, regulation of exhaustion, and response to checkpoint blockade. Here, we report the isolation and characterization of LCMV Minnesota (LCMV-MN), which was naturally transmitted to laboratory mice upon cohousing with pet shop mice and shares 80-95% amino acid homology with previously characterized LCMV strains. Infection of laboratory mice with purified LCMV-MN resulted in viral persistence that was intermediate between LCMV Armstrong and Clone 13, with widely disseminated viral replication and viremia that was controlled within 15-30 days, unless CD4 T cells were depleted prior to infection. LCMV-MN responding CD8+ T cells biased differentiation towards the recently described PD1+ CXCR5+ Tim-3lo stem-like CD8+ T cell population (also referred to as T exhausted progenitors, Tpex) that effectuates responses to PD-1 blockade checkpoint inhibition, a therapy that rejuvenates responses against chronic infections and cancer. This subset resembled previously characterized PD1+ TCF1+ stem-like CD8+ T cells by transcriptional, phenotypic, and functional assays, yet was atypically abundant. LCMV-MN may provide a tool to better understand the breadth of immune responses in different settings of chronic antigen stimulation as well as the ontogeny of T exhausted progenitors and the regulation of responsiveness to PD-1 blockade.
Project description:CD4+ T cell help is critical for optimal CD8+ T cell expansion after priming in many experimental systems. However, a role for CD4+ T cells in regulating the initial steps of CD8+ T cell effector differentiation is not well established. Here we demonstrate that absence of CD4+ T cells at the time of replication-incompetent adenovirus vector immunization of C57BL/6 mice led to immediate CD8+ T cell dysfunction characteristic of exhaustion at the first detectable timepoints as well as impaired expansion of antigen-specific CD8+ T cells. The absence of CD4+ T cell help resulted in antigen-specific CD8+ T cells that had reduced ex vivo cytotoxicity and decreased capacity to produce IFN-γ and TNF-α. CD8+ T cells primed in the absence of CD4+ T cells expressed elevated levels of the inhibitory receptors PD-1, LAG-3, and Tim-3, and these cells exhibited transcriptomic exhaustion profiles by gene set enrichment analysis. This dysfunctional state was imprinted within 3 days of immunization and could not be reversed by provision of CD4+ T cell help after priming. Partial rescue of unhelped CD8+ T cell expansion and effector differentiation could be achieved by PD-1 pathway blockade or recombinant IL-2 administration. This study identifies a novel, previously undescribed role of CD4+ T cells to prevent immediate dysfunction and features of exhaustion in CD8+ T cells following antigen priming. Splenic AL11-specific CD8 T cells from mice immunized with Ad5HVR48(1-7)-SIV Gag and treated with anti-CD4 antibody or not were purified by FACS on day 14 post-immunization
Project description:Cytotoxic T cells (CTLs) play a crucial role in the elimination of cancer cells. However, within the intra-tumor microenvironment, these cells eventually undergo cell death or enter a state of dysfunction known as "exhaustion". T cell exhaustion not only impairs the efficacy of tumor immunity but also contributes to resistance against immune-checkpoint inhibitors. Our previous investigations have demonstrated that the NR4a family of nuclear receptors, induced by chronic TCR stimulation, plays a pivotal role in driving exhaustion. These receptors enhance the transcription of inhibitory molecules, such as PD1, while suppressing the expression of functional molecules, including cytokines. However, it remains unclear at which stage of T cell differentiation NR4a exerts its influence and whether the loss of NR4a can "rejuvenate" T cell fate. In the present study, we confirmed that simultaneous deletion of NR4a1 and NR4a2 in CD8+ T cells led to a less exhausted phenotype characterized by reduced expression of PD1, Tim3, and Tox, as well as increased oxidative phosphorylation (OXPHOS) and glycolysis activities, resulting in potent suppression of tumor growth. Interestingly, the transfer of activated NR4a1-/-NR4a2-/-CD8+ T cells into tumor-bearing mice gave rise to TCF1+ (Tcf7+) early memory T cells. Wild-type PD1+TIM3+CD8+ tumor-infiltrating lymphocytes (TILs) diminished in the secondary transfer to tumor-bearing mice, while NR4a-deficient CD8+ TILs expanded even during the secondary transfer, indicating a strong stemness of memory T cells due to NR4a loss. We discovered that NR4a directly repressed the expression of Tcf7 by binding to the enhancer region of the Tcf7 gene. Collectively, these findings indicate that inhibiting NR4a in tumors represents a potent strategy for immuno-oncotherapy by enhancing stemness and reducing exhaustion of memory T cells.
Project description:Cytotoxic T cells (CTLs) play a crucial role in the elimination of cancer cells. However, within the intra-tumor microenvironment, these cells eventually undergo cell death or enter a state of dysfunction known as "exhaustion". T cell exhaustion not only impairs the efficacy of tumor immunity but also contributes to resistance against immune-checkpoint inhibitors. Our previous investigations have demonstrated that the NR4a family of nuclear receptors, induced by chronic TCR stimulation, plays a pivotal role in driving exhaustion. These receptors enhance the transcription of inhibitory molecules, such as PD1, while suppressing the expression of functional molecules, including cytokines. However, it remains unclear at which stage of T cell differentiation NR4a exerts its influence and whether the loss of NR4a can "rejuvenate" T cell fate. In the present study, we confirmed that simultaneous deletion of NR4a1 and NR4a2 in CD8+ T cells led to a less exhausted phenotype characterized by reduced expression of PD1, Tim3, and Tox, as well as increased oxidative phosphorylation (OXPHOS) and glycolysis activities, resulting in potent suppression of tumor growth. Interestingly, the transfer of activated NR4a1-/-NR4a2-/-CD8+ T cells into tumor-bearing mice gave rise to TCF1+ (Tcf7+) early memory T cells. Wild-type PD1+TIM3+CD8+ tumor-infiltrating lymphocytes (TILs) diminished in the secondary transfer to tumor-bearing mice, while NR4a-deficient CD8+ TILs expanded even during the secondary transfer, indicating a strong stemness of memory T cells due to NR4a loss. We discovered that NR4a directly repressed the expression of Tcf7 by binding to the enhancer region of the Tcf7 gene. Collectively, these findings indicate that inhibiting NR4a in tumors represents a potent strategy for immuno-oncotherapy by enhancing stemness and reducing exhaustion of memory T cells.
Project description:Cytotoxic T cells (CTLs) play a crucial role in the elimination of cancer cells. However, within the intra-tumor microenvironment, these cells eventually undergo cell death or enter a state of dysfunction known as "exhaustion". T cell exhaustion not only impairs the efficacy of tumor immunity but also contributes to resistance against immune-checkpoint inhibitors. Our previous investigations have demonstrated that the NR4a family of nuclear receptors, induced by chronic TCR stimulation, plays a pivotal role in driving exhaustion. These receptors enhance the transcription of inhibitory molecules, such as PD1, while suppressing the expression of functional molecules, including cytokines. However, it remains unclear at which stage of T cell differentiation NR4a exerts its influence and whether the loss of NR4a can "rejuvenate" T cell fate. In the present study, we confirmed that simultaneous deletion of NR4a1 and NR4a2 in CD8+ T cells led to a less exhausted phenotype characterized by reduced expression of PD1, Tim3, and Tox, as well as increased oxidative phosphorylation (OXPHOS) and glycolysis activities, resulting in potent suppression of tumor growth. Interestingly, the transfer of activated NR4a1-/-NR4a2-/-CD8+ T cells into tumor-bearing mice gave rise to TCF1+ (Tcf7+) early memory T cells. Wild-type PD1+TIM3+CD8+ tumor-infiltrating lymphocytes (TILs) diminished in the secondary transfer to tumor-bearing mice, while NR4a-deficient CD8+ TILs expanded even during the secondary transfer, indicating a strong stemness of memory T cells due to NR4a loss. We discovered that NR4a directly repressed the expression of Tcf7 by binding to the enhancer region of the Tcf7 gene. Collectively, these findings indicate that inhibiting NR4a in tumors represents a potent strategy for immuno-oncotherapy by enhancing stemness and reducing exhaustion of memory T cells.
Project description:Cytotoxic T cells (CTLs) play a crucial role in the elimination of cancer cells. However, within the intra-tumor microenvironment, these cells eventually undergo cell death or enter a state of dysfunction known as "exhaustion". T cell exhaustion not only impairs the efficacy of tumor immunity but also contributes to resistance against immune-checkpoint inhibitors. Our previous investigations have demonstrated that the NR4a family of nuclear receptors, induced by chronic TCR stimulation, plays a pivotal role in driving exhaustion. These receptors enhance the transcription of inhibitory molecules, such as PD1, while suppressing the expression of functional molecules, including cytokines. However, it remains unclear at which stage of T cell differentiation NR4a exerts its influence and whether the loss of NR4a can "rejuvenate" T cell fate. In the present study, we confirmed that simultaneous deletion of NR4a1 and NR4a2 in CD8+ T cells led to a less exhausted phenotype characterized by reduced expression of PD1, Tim3, and Tox, as well as increased oxidative phosphorylation (OXPHOS) and glycolysis activities, resulting in potent suppression of tumor growth. Interestingly, the transfer of activated NR4a1-/-NR4a2-/-CD8+ T cells into tumor-bearing mice gave rise to TCF1+ (Tcf7+) early memory T cells. Wild-type PD1+TIM3+CD8+ tumor-infiltrating lymphocytes (TILs) diminished in the secondary transfer to tumor-bearing mice, while NR4a-deficient CD8+ TILs expanded even during the secondary transfer, indicating a strong stemness of memory T cells due to NR4a loss. We discovered that NR4a directly repressed the expression of Tcf7 by binding to the enhancer region of the Tcf7 gene. Collectively, these findings indicate that inhibiting NR4a in tumors represents a potent strategy for immuno-oncotherapy by enhancing stemness and reducing exhaustion of memory T cells.
Project description:Cytotoxic T cells (CTLs) play a crucial role in the elimination of cancer cells. However, within the intra-tumor microenvironment, these cells eventually undergo cell death or enter a state of dysfunction known as "exhaustion". T cell exhaustion not only impairs the efficacy of tumor immunity but also contributes to resistance against immune-checkpoint inhibitors. Our previous investigations have demonstrated that the NR4a family of nuclear receptors, induced by chronic TCR stimulation, plays a pivotal role in driving exhaustion. These receptors enhance the transcription of inhibitory molecules, such as PD1, while suppressing the expression of functional molecules, including cytokines. However, it remains unclear at which stage of T cell differentiation NR4a exerts its influence and whether the loss of NR4a can "rejuvenate" T cell fate. In the present study, we confirmed that simultaneous deletion of NR4a1 and NR4a2 in CD8+ T cells led to a less exhausted phenotype characterized by reduced expression of PD1, Tim3, and Tox, as well as increased oxidative phosphorylation (OXPHOS) and glycolysis activities, resulting in potent suppression of tumor growth. Interestingly, the transfer of activated NR4a1-/-NR4a2-/-CD8+ T cells into tumor-bearing mice gave rise to TCF1+ (Tcf7+) early memory T cells. Wild-type PD1+TIM3+CD8+ tumor-infiltrating lymphocytes (TILs) diminished in the secondary transfer to tumor-bearing mice, while NR4a-deficient CD8+ TILs expanded even during the secondary transfer, indicating a strong stemness of memory T cells due to NR4a loss. We discovered that NR4a directly repressed the expression of Tcf7 by binding to the enhancer region of the Tcf7 gene. Collectively, these findings indicate that inhibiting NR4a in tumors represents a potent strategy for immuno-oncotherapy by enhancing stemness and reducing exhaustion of memory T cells.