Project description:Prostaglandin E2 (PGE2) is overexpressed in many tumors and plays an important role in suppressing T-cell function. In this study, we investigated the effect of PGE2 in human T-cells. Importantly, PGE2 caused profound transcriptomic changes both in unstimulated and exhausted T-cells with many genes and pathways altered including T-cell lipid metabolism. Our study suggests that PGE2-induced metabolic reprogramming is detrimental to dysfunctional T-cells and TIL, and its manipulation could be used to dampen the immunosuppressive effects of PGE2.
Project description:CD8 T cells normally differentiate from resting naïve T cells into function effector and then memory CD8 T cells following acute infections. During chronic viral infections, however, virus-specific CD8 T cells often become exhausted. We used microarrays to examine the gene expression differences between naive, effector, memory and exhausted virus-specific CD8 T cells following lymphocytic choriomeningitis virus infection. Experiment Overall Design: Three or four independent samples were sorted by flow cytometry for each cell type (naive, effector, memory and exhausted) virus-specific CD8 T cells. RNA was extracted and hybridized to Affymetrix microarrays.
Project description:Exhausted T cells express multiple co-inhibitory molecules that impair their function and limit immunity to chronic viral infection. Defining novel markers of exhaustion is important both for identifying and potentially reversing T cell exhaustion. Herein, we show that the ectonucleotidse CD39 is a marker of exhausted CD8+ T cells. CD8+ T cells specific for HCV or HIV express high levels of CD39, but those specific for EBV and CMV do not. CD39 expressed by CD8+ T cells in chronic infection is enzymatically active, co-expressed with PD-1, marks cells with a transcriptional signature of T cell exhaustion and correlates with viral load in HIV and HCV. In the mouse model of chronic Lymphocytic Choriomeningitis Virus infection, virus-specific CD8+ T cells contain a population of CD39high CD8+ T cells that is absent in functional memory cells elicited by acute infection. This CD39high CD8+ T cell population is enriched for cells with the phenotypic and functional profile of terminal exhaustion. These findings provide a new marker of T cell exhaustion, and implicate the purinergic pathway in the regulation of T cell exhaustion. CD8+ T cells from subjects with HCV infection were sorted and pelleted and re-suspended in TRIzol (Invitrogen). RNA extraction was performed using the RNAdvance Tissue Isolation kit (Agencourt). Concentrations of total RNA were determined with a Nanodrop spectrophotometer or Ribogreen RNA quantification kits (Molecular Probes/Invitrogen). RNA purity was determined by Bioanalyzer 2100 traces (Agilent Technologies). Total RNA was amplified with the WT-Ovation Pico RNA Amplification system (NuGEN) according to the manufacturer's instructions. After fragmentation and biotinylation, cDNA was hybridized to HG-U133A 2.0 microarrays (Affymetrix).
Project description:While the role of prostaglandin E2 (PGE2) in promoting malignant progression is well-established, how to optimally block the activity of PGE2 signaling remains to be demonstrated. Clinical trials with prostaglandin pathway targeted agents have shown activity but without sufficient significance or dose-limiting toxicities that have prevented approval. PGE2 signals through four receptors (EP1-4) to modulate tumor progression. EP2 and EP4 signaling exacerbates tumor pathology and is immunosuppressive through potentiating cAMP production. EP1 and EP3 signaling has the opposite effect through increasing IP3 and decreasing cAMP. Using available small molecule antagonists of single EP receptors, the COX-2 inhibitor celecoxib, or a novel dual EP2/EP4 antagonist generated in this investigation, we tested which approach to block PGE2 signaling optimally restored immunologic activity in mouse and human immune cells and antitumor activity in syngeneic, spontaneous and xenograft tumor models. We found that dual antagonism of EP2 and EP4 together significantly enhanced the activation of PGE2-suppressed mouse and human monocytes and CD8+ T cells in vitro as compared to single EP antagonists. CD8+ T cell activation was dampened by single EP1 and EP3 antagonists. Dual EP2/EP4 PGE2 receptor antagonists increased TME lymphocyte infiltration and significantly reduced disease burden in multiple tumor models, including in the adenomatous polyposis coli (APC)min+/- spontaneous colorectal tumor model, compared to celecoxib. These results support a hypothesis that redundancy of EP2 and EP4 receptor signaling necessitates a therapeutic strategy of dual blockade of EP2 and EP4. Here we describe TPST-1495, a first-in-class orally available small molecule dual EP2/EP4 antagonist.
Project description:TGFb signaling is a major pathway associated with poor clinical outcome in patients with
advanced metastatic cancers and non-response to immune checkpoint blockade, particularly in the immune-excluded tumor phenotype. While previous pre-clinical studies demonstrated that converting tumors from an excluded to an inflamed phenotype and curative anti-tumor immunity require attenuation of both PD-L1 and TGFb signaling, the underlying cellular mechanisms remain unclear. Recent studies suggest that stem cell-like CD8 T cells (TSCL) can differentiate into non-exhausted CD8 T effector cells that drive durable anti-tumor immunity. Here, we show that TGFb and PD-L1 restrain TSCL expansion as well as replacement of progenitor exhausted and dysfunctional CD8 T cells with non-exhausted IFNghi CD8 T effector cells in the tumor microenvironment (TME). Blockade of TGFb and PD-L1 generated IFNghi CD8 T effector cells with enhanced motility, enabling both their accumulation in the TME and increased interaction with other cell types. Ensuing IFNg signaling markedly transformed myeloid, stromal, and tumor niches to yield a broadly immune-supportive ecosystem. Blocking IFNg completely abolished the effect of anti-PD-L1/ TGFb combination therapy. Our data suggest that TGFb works in concert with PD-L1 to prevent TSCL expansion and replacement of exhausted CD8 T cells with fresh CD8
T effector cells, thereby maintaining the CD8 T cell compartment in a dysfunctional state.
Project description:CD8 T cells normally differentiate from resting naïve T cells into function effector and then memory CD8 T cells following acute infections. During chronic viral infections, however, virus-specific CD8 T cells often become exhausted. We used microarrays to examine the gene expression differences between naive, effector, memory and exhausted virus-specific CD8 T cells following lymphocytic choriomeningitis virus infection. Keywords: infection response
Project description:Since exhausted CD8 T-cells are known to have a strong epigenetic imprint, which is a major obstacle for reinvigoration, we investigated whether the induced Klf4 expression could change the epigenetic status of the exhausted CD8 T-cells. For this, we performed ATAC-sequencing and compared chromatin landscapes between naïve, in vitro generated effector, exhausted (GFP-induced), and reinvigorated (KLF4-induced) CD8 T-cells.