Exhausted Tumor-infiltrating CD39+CD103+ CD8+ T Cells Unveil Potential for Increased Survival in Human Pancreatic Cancer.

In pancreatic ductal adenocarcinoma, the infiltration of CD8+ T cells within the tumor microenvironment correlates with a favorable prognosis. However, a significant proportion of tumor-infiltrating T cells become trapped within the desmoplastic stroma and lack tumor reactivity. Here, we explored different T-cell subsets in pancreatic tumors and adjacent tissues. We identified a subset of CD8+ T cells, double positive (DP) for CD39 and CD103 in pancreatic tumors, which has recently been described to display tumor reactivity in other types of solid tumors. Interestingly, DP CD8+ T cells preferentially accumulated in central tumor tissues compared with paired peripheral tumor and adjacent non-tumor tissues. Consistent with an antigen encounter, DP CD8+ T cells demonstrated higher proliferative rates and displayed an exhausted phenotype, characterized by elevated expression of PD-1 and TIM-3, compared with CD39-CD103- CD8+ T cells. In addition, DP CD8+ T cells exhibited higher expression levels of the tissue trafficking receptors CCR5 and CXCR6, while displaying lower levels of CXCR3 and CXCR4. Importantly, a high proportion of DP CD8+ T cells is associated with increased patient survival. These findings suggest that DP CD8+ T cells with a phenotype reminiscent of that of tumor-reactive T cells are present in pancreatic tumors. The abundance of DP CD8+ T cells could potentially aid in selecting patients for pancreatic cancer immunotherapy trials. SIGNIFICANCE: Patients with pancreatic cancer with a high proportion of CD39+CD103+ CD8+ T cells exhibiting a tumor-reactive phenotype have improved survival rates, suggesting their potential utility in selecting candidates for immunotherapy trials.

FPR2 Shapes an Immune-Excluded Pancreatic Tumor Microenvironment and Drives T-cell Exhaustion in a Sex-Dependent Manner.

Sex-driven immune differences can affect tumor progression and the landscape of the tumor microenvironment. Deeper understanding of these differences in males and females can inform patient selection to improve sex-optimized immunotherapy treatments. In this study, single-cell RNA sequencing and protein analyses uncovered a subpopulation of myeloid cells in pancreatic lesions associated with an immune-excluded tumor phenotype and effector T-cell exhaustion exclusively in females. This myeloid subpopulation was positively correlated with poor survival and genetic signatures of M2-like macrophages and T-cell exhaustion in females. The G-protein coupled receptor formyl peptide receptor 2 (FPR2) mediated these immunosuppressive effects. In vitro, treatment of myeloid cells with a specific FPR2 antagonist prevented exhaustion and enhanced cytotoxicity of effector cells. Proteomic analysis revealed high expression of immunosuppressive secretory proteins PGE2 and galectin-9, enriched integrin pathway, and reduced proinflammatory signals like TNFα and IFNγ in female M2-like macrophages upon FPR2 agonist treatment. In addition, myeloid cells treated with FPR2 agonists induced TIM3 and PD-1 expression only in female T cells. Treatment with anti-TIM3 antibodies reversed T-cell exhaustion and stimulated their ability to infiltrate and kill pancreatic spheroids. In vivo, progression of syngeneic pancreatic tumors was significantly suppressed in FPR2 knockout (KO) female mice compared with wild-type (WT) female mice and to WT and FPR2 KO male mice. In female mice, inoculation of tumors with FPR2 KO macrophages significantly reduced tumor growth compared with WT macrophages. Overall, this study identified an immunosuppressive function of FPR2 in females, highlighting a potential sex-specific precision immunotherapy strategy. SIGNIFICANCE: FPR2 is a sex-dependent mediator of macrophage function in pancreatic cancer and can be targeted to reprogram macrophages and stimulate antitumor immunity in females.

Targeting myeloid suppressive cells revives cytotoxic anti-tumor responses in pancreatic cancer.

Immunotherapy for cancer that aims to promote T cell anti-tumor activity has changed current clinical practice, where some previously lethal cancers have now become treatable. However, clinical trials with low response rates have been disappointing for pancreatic ductal adenocarcinoma (PDAC). One suggested explanation is the accumulation of dominantly immunosuppressive tumor-associated macrophages and myeloid-derived suppressor cells in the tumor microenvironment (TME). Using retrospectively collected tumor specimens and transcriptomic data from PDAC, we demonstrate that expression of the scavenger receptor MARCO correlates with poor prognosis and a lymphocyte-excluding tumor phenotype. PDAC cell lines produce IL-10 and induce high expression of MARCO in myeloid cells, and this was further enhanced during hypoxic conditions. These myeloid cells suppressed effector T and natural killer (NK) cells and blocked NK cell tumor infiltration and tumor killing in a PDAC 3D-spheroid model. Anti-human MARCO (anti-hMARCO) antibody targeting triggered the repolarization of tumor-associated macrophages and activated the inflammasome machinery, resulting in IL-18 production. This in turn enhanced T cell and NK cell functions. The targeting of MARCO thus remodels the TME and represents a rational approach to make immunotherapy more efficient in PDAC patients.

Potential for Screening for Pancreatic Exocrine Insufficiency Using the Fecal Elastase-1 Test.

The early diagnosis of pancreatic exocrine insufficiency (PEI) is hindered because many of the functional diagnostic techniques used are expensive and require specialized facilities, which prevent their widespread availability. We have reviewed current evidence in order to compare the utility of these functional diagnostic techniques with the fecal elastase-1 (FE-1) test in the following three scenarios: screening for PEI in patients presenting with symptoms suggestive of pancreatic disease, such as abdominal pain or diarrhea; determining the presence of PEI in patients with an established diagnosis of pancreatic disease, such as chronic pancreatitis or cystic fibrosis; determining exocrine status in disorders not commonly tested for PEI, but which have a known association with this disorder. Evidence suggests the FE-1 test is reliable for the evaluation of pancreatic function in many pancreatic and non-pancreatic disorders. It is non-invasive, is less time-consuming, and is unaffected by pancreatic enzyme replacement therapy. Although it cannot be considered the gold-standard method for the functional diagnosis of PEI, the advantages of the FE-1 test make it a very appropriate test for screening patients who may be at risk of this disorder.

Survival Analysis and Risk for Progression of Intraductal Papillary Mucinous Neoplasia of the Pancreas (IPMN) Under Surveillance: A Single-Institution Experience.

PURPOSE: While surveillance of the majority of patients with IPMN is considered best practice, consensus regarding the duration of follow-up is lacking. This study assessed the survival rate and risk for progression of IPMN under surveillance. METHODS: All patients diagnosed with and surveyed for IPMN between January 2008 and December 2013 were identified and assigned to two groups: patients without indication for surgery (Group 1), and patients whose IPMN required surgery but were inoperable for general reasons (Group 2). Disease progression and survival data were compared between both groups. RESULTS: In total 503 patients were identified, of whom 444 (88.3%) were followed up. Group 1 included 395 patients, and Group 2 had 49. In Group 1, IPMN-specific 1-, 5-, and 10-year survival rates were 100, 100, and 94.2%, respectively. Four patients died of associated or concomitant pancreatic cancer, and 230 patients (58.2%) experienced disease progression. The 1-, 4-, 10-year cumulative risk for progression and for surgery was 11.2, 70.6, 97.5, and 2.9, 26.2, 72.1%, respectively. In Group 2, the 1-, 5-, 10-year IPMN-specific survival rate was 90.7, 74.8, and 74.8%, respectively. CONCLUSIONS: This study confirmed the safety of surveillance for patients with IPMN who do not require surgery. However, the risk for disease progression and for surgery increases significantly over time. The study results support International and European guidelines not to discontinue IPMN surveillance and validate the European recommendation to intensify follow-up after 5 years. The fairly good prognosis of patients whose IPMN requires surgery but cannot undergo resection suggests a relatively indolent disease biology.