Circulating regulatory T cell subsets predict overall survival of patients with unresectable pancreatic cancer

In-depth immune profiling of peripheral blood mononuclear cells in patients with pancreatic ductal adenocarcinoma reveals discriminative immune subpopulations

Pancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis with a 5-year survival of less than 10%. More knowledge of the immune response developed in patients with PDAC is pivotal to develop better combination immune therapies to improve clinical outcome. In this study, we used mass cytometry time-of-flight to undertake an in-depth characterization of PBMCs from patients with PDAC and examine the differences with healthy controls and patients with benign diseases of the biliary system or pancreas. Peripheral blood mononuclear cells from patients with PDAC or benign disease are characterized by the increase of pro-inflammatory cells, as CD86+ classical monocytes and memory T cells expressing CCR6+ and CXCR3+, associated with T helper 1 (Th1) and Th17 immune responses, respectively. However, PBMCs from patients with PDAC present also an increase of CD39+ regulatory T cells and CCR4+CCR6-CXCR3- memory T cells, suggesting Th2 and regulatory responses. Concluding, our results show PDAC develops a multifaceted immunity, where a proinflammatory component is accompanied by regulatory responses, which could inhibit potential antitumor mechanisms.

The relationship between splenic dose and radiation-induced lymphopenia

Lymphocytes, which are highly sensitive to radiation, play a crucial role in the body's defense against tumors. Radiation-induced lymphopenia has been associated with poorer outcomes in different cancer types. Despite being the largest secondary lymphoid organ, the spleen has not been officially designated as an organ at risk. This study hypothesizes a connection between spleen irradiation and lymphopenia and seeks to establish evidence-based dosage limits for the spleen. We retrospectively analyzed data from 96 patients with locally advanced gastric cancer who received postoperative chemoradiotherapy (CRT) between May 2010 and May 2017. Complete blood counts were collected before, during and after CRT. We established a model for predicting the minimum absolute lymphocyte count (Min ALC) and to investigate potential associations between spleen dosimetric variables and Min ALC. The median follow-up was 60 months. The 5-year overall survival (OS) and disease-free survival (DFS) were 65.2% and 56.8%, respectively. The median values of pre-treatment ALC, Min ALC and post-treatment ALC were 1.40 × 109, 0.23 × 109 and 0.28 × 109/L, respectively. Regression analysis confirmed that the primary tumor location, number of fractions and spleen V5 were significant predictors of Min ALC during radiation therapy. Changes in ALC (ΔALC) were identified as an independent predictor of both OS and DFS. Spleen V5 is an independent predictor for Min ALC, and the maximum dose of the spleen is associated with an increased risk of severe lymphopenia. Therefore, these doses should be restricted in clinical practice. Additionally, ΔALC can serve as a prognostic indicator for adjuvant radiotherapy in gastric cancer.

Peripheral blood lymphocyte subsets predict the efficacy of TACE with or without PD-1 inhibitors in patients with hepatocellular carcinoma: a prospective clinical study

Background

Although peripheral blood lymphocyte subsets, particularly PD-1+ T cells, are promising prognostic indicators for patients with cancer. However, their clinical significance remains unclear.

Methods

We prospectively enrolled 157 patients with hepatocellular carcinoma (HCC) treated with transcatheter arterial chemoembolization combined with or without PD-1 inhibitors. Twenty peripheral lymphocyte subsets and cytokines were analyzed. We analyzed the differences in PD-1+ T cells between patients treated with and without PD-1 inhibitors and their associations with tumor response, survival prognosis, and clinical features.

Results

We found that the baseline CD8+PD-1+ and CD4+PD-1+ T-cell frequencies in patients who had received PD-1 inhibitors were lower than those in patients who had not received PD-1 inhibitors (p < 0.001). In the former patients, there were no differences in PD-1+ T-cell frequencies between the responder and non-responder subgroups (p > 0.05), whereas in the latter patients, the levels of CD8+PD-1+ T cells, CD4+PD-1+ T cells, and CD8+PD-1+/CD4+PD-1+ ratio did not predict tumor response, progression-free survival (PFS), or overall survival (OS) (p>0.05). Furthermore, in multivariate analysis of patients treated with or without PD-1 inhibitors revealed that the levels of CD8+CD38+ T cells (OR = 2.806, p = 0.006) were associated with tumor response, whereas those of CD8+CD28+ T cells (p = 0.038, p = 0.001) and natural killer (NK) cells (p = 0.001, p = 0.027) were associated with PFS and OS. Although, these independent prognostic factors were associated with progressive tumor characteristics (p<0.05), with the exception of CD8+CD28+ T cells, changes in these factors before and after treatment were unassociated with tumor response (p > 0.05).

Conclusion

Circulating CD8+CD38+ T cells, CD8+CD28+ T cells, and NK cells were identified as potential prognostic factors for tumor response and survival in patients with HCC. Contrastingly, although PD-1 inhibitors can effectively block the T cell PD-1 receptor, the baseline PD-1+ T-cell frequencies and changes in the frequency of these cells have limited prognostic value.

IL-35: New Target for Immunotherapy Targeting the Tumor Microenvironment

Interleukin 35(IL-35) is a newly discovered inhibitory cytokine of the IL12 family. More recently, IL-35 was found to be increased in the tumor microenvironment (TME) and peripheral blood of many patients with cancer, indicating that it plays an important role in the TME. Tumors secrete cytokines that recruit myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Treg) into the TME to promote malignant progression, which is a great challenge for cancer treatment. Radiotherapy causes serious adverse effects, and tumor resistance to immune checkpoint inhibitors is still an unsolved challenge. Thus, new cancer therapy approaches are urgently needed. Numerous studies have shown that IL-35 can recruit immunosuppressive cells to enable tumor immune escape by promoting the conversion of immune cells into a tumor growth-promoting phenotype as well as facilitating tumor angiogenesis. IL-35-neutralizing antibodies were found to boost the chemotherapeutic effect of gemcitabine and considerably reduce the microvascular density of pancreatic cancer in mice. Therefore, targeting IL-35 in the TME provides a promising cancer treatment target. In addition, IL-35 may be used as an independent prognostic factor for some tumors in the near future. This review intends to reveal the interplay of IL-35 with immune cells in the TME, which may provide new options for the treatment of cancer.

Tissue Resistance Decrease during Irreversible Electroporation of Pancreatic Cancer as a Biomarker for the Adaptive Immune Response and Survival

PURPOSE

To correlate irreversible electroporation (IRE) procedural resistance changes with survival outcomes and the IRE-induced systemic immune response in patients with locally advanced pancreatic cancer (LAPC).

MATERIALS AND METHODS

Data on IRE procedural tissue resistance (R) features and survival outcomes were collected from patients with LAPC treated within the context of 2 prospective clinical trials in a single tertiary center. Preprocedural and postprocedural peripheral blood samples were prospectively collected for immune monitoring. The change (ie, decrease) in R during the first 10 test pulses (ΔR10p) and during the total procedure (ΔRtotal) were calculated. Patients were divided in 2 groups on the basis of the median change in R (large ΔR vs small ΔR) and compared for differences in overall survival (OS) and progression-free survival and immune cell subsets.

RESULTS

A total of 54 patients were included; of these, 20 underwent immune monitoring. Linear regression modeling showed that the first 10 test pulses reflected the change in tissue resistance during the total procedure appropriately (P < .001; R2 = 0.91). A large change in tissue resistance significantly correlated with a better OS (P = .026) and longer time to disease progression (P = .045). Furthermore, a large change in tissue resistance was associated with CD8+ T cell activation through significant upregulation of Ki-67+ (P = .02) and PD-1+ (P = .047). Additionally, this subgroup demonstrated significantly increased expression of CD80 on conventional dendritic cells (cDC1; P = .027) and PD-L1 on immunosuppressive myeloid-derived suppressor cells (P = .039).

CONCLUSIONS

IRE procedural resistance changes may serve as a biomarker for survival and IRE-induced systemic CD8+ T cell and cDC1 activation.

A Novel HOXA10-Associated 5-Gene-Based Prognostic Signature for Stratification of Short-term Survivors of Pancreatic Ductal Adenocarcinoma

PURPOSE

Despite the significant association of molecular subtypes with poor prognosis in patients with pancreatic ductal adenocarcinoma (PDAC), few efforts have been made to identify the underlying pathway(s) responsible for this prognosis. Identifying a clinically relevant prognosis-based gene signature may be the key to improving patient outcomes.

EXPERIMENTAL DESIGN

We analyzed the transcriptomic profiles of treatment-naïve surgically resected short-term survivor (STS) and long-term survivor (LTS) tumors (GSE62452) for expression and survival, followed by validation in several datasets. These results were corroborated by IHC analysis of PDAC-resected STS and LTS tumors. The mechanism of this differential survival was investigated using CIBERSORT and pathway analyses.

RESULTS

We identified a short-surviving prognostic subtype of PDAC with a high degree of significance (P = 0.018). One hundred thirty genes in this novel subtype were found to be regulated by a master regulator, homeobox gene HOXA10, and a 5-gene signature derived from these genes, including BANF1, EIF4G1, MRPS10, PDIA4, and TYMS, exhibited differential expression in STSs and a strong association with poor survival. This signature was further associated with the proportion of T cells and macrophages found in STSs and LTSs, demonstrating a potential role in PDAC immunosuppression. Pathway analyses corroborated these findings, revealing that this HOXA10-driven prognostic signature is associated with immune suppression and enhanced tumorigenesis.

CONCLUSIONS

Overall, these findings reveal the presence of a HOXA10-associated prognostic subtype that can be used to differentiate between STS and LTS patients of PDAC and inform on the molecular interactions that play a role in this poor prognosis.

Mechanistic Insights into the Roles of the IL-17/IL-17R Families in Pancreatic Cancer

The members of the cytokine interleukin 17 (IL-17) family, along with their receptors (IL-17R), are vital players in a range of inflammatory diseases and cancer. Although generally regarded as proinflammatory, the effects they exhibit on cancer progression are a double-edged sword, with both antitumor and protumor activities being discovered. There is growing evidence that the IL-17 signaling pathways have significant impacts on the tumor microenvironment (TME), immune response, and inflammation in various types of cancer, including pancreatic cancer. However, the detailed mechanistic functions of the IL-17/IL-17R families in pancreatic cancer were rarely systematically elucidated. This review considers the role of the IL-17/IL-17R families in inflammation and tumor immunity and elaborates on the mechanistic functions and correlations of these members with pathogenesis, progression, and chemoresistance in pancreatic cancer. By summarizing the advanced findings on the role of IL-17/IL17R family members and IL-17 signaling pathways at the molecular level, cellular level, and disease level in pancreatic cancer, this review provides an in-depth discussion on the potential of IL-17/IL-17R as prognostic markers and therapeutic targets in pancreatic cancer.

Immunomodulatory Effects of Endoscopic Ultrasound-Guided Thermal Ablation in Patients with Pancreatic Ductal Adenocarcinoma

Immunological consequences of endoscopic ultrasound (EUS)-local thermal ablation (LTA) for pancreatic ductal adenocarcinoma (PDAC) have not been extensively assessed. We aimed to explore EUS-LTA effects on the systemic immune response in PDAC. Peripheral blood was collected from 10 treatment-naïve patients with borderline resectable and locally advanced PDAC, randomly allocated to Nab-paclitaxel plus Gemcitabine chemotherapy (CT-arm, n = 5) or EUS-LTA with HybridTherm Probe plus CT (HTP + CT-arm, n = 5). Twenty healthy donors were included as controls. Flow-cytometry and multiplex assays were used to profile immune cell subsets and measure serum cytokines/chemokines, respectively. At baseline, PDAC patients showed increased circulating monocytes and lower circulating lymphocytes and CD19+ B cells counts compared to healthy controls. After 4 months, CT induced decrease of B regulatory cells, CD4+ cytotoxic T cells and IL-1β. The addition of EUS-HTP to CT selectively decreased the serum levels of APRIL/TNFSF13 as well as T regulatory cells, total, classic and inflammatory monocytes. Serum levels of APRIL/TNFSF13 and total, classic and inflammatory monocytes counts at baseline were associated with worse overall survival. EUS-HTP has the potential to selectively impact on immune cells and cytokines associated with poor outcomes in PDAC.

Construction of a metabolism-related gene prognostic model to predict survival of pancreatic cancer patients

Pancreatic cancer (PC) is one of the most fatal malignant tumors, and is commonly diagnosed at an advanced stage with no effective therapy. Metabolism-related genes (MRGs) and immune-related genes (IRGs) play considerable roles in the tumor microenvironment. Therefore, an effective prediction model based on MRGs and IRGs could aid in the prognosis of PC. In this study, differential expression analysis was performed to gain 25 intersectional genes from 857 differentially expressed MRGs (DEMRGs), and 1353 differentially expressed IRGs, from The Cancer Genome Atlas database of PC. Cox and Lasso regression were applied and a five-DEMRGs prognostic model constructed. Survival analysis, ROC values, risk curve and validation analysis showed that the model could independently predict PC prognosis. In addition, the correlation analysis suggested that the five-DEMRGs prognostic model could reflect the status of the immune microenvironment, including Tregs, M1 macrophages and Mast cell resting. Therefore, our study provides new underlying predictive biomarkers and associated immunotherapy targets.

Cytokines and Lymphoid Populations as Potential Biomarkers in Locally and Borderline Pancreatic Adenocarcinoma

Despite its relative low incidence, PDAC is one of the most aggressive and lethal types of cancer, being currently the seventh leading cause of cancer death worldwide, with a 5-year survival rate of 10.8%. Taking into consideration the necessity to improve the prognosis of these patients, this research has been focused on the discovery of new biomarkers. For this purpose, patients with BL and resectable disease were recruited. Serum cytokines and growth factors were monitored at different time points using protein arrays. Immune cell populations were determined by flow cytometry in peripheral blood as well as by immunohistochemistry (IHC) in tumor tissues. Several cytokines were found to be differentially expressed between the study subgroups. In the BL disease setting, two different scores were proven to be independent prognostic factors for progression-free survival (PFS) (based on IL-10, MDC, MIF, and eotaxin-3) and OS (based on eotaxin-3, NT-3, FGF-9, and IP10). In the same context, CA19-9 was found to play a role as independent prognostic factor for OS. Eotaxin-3 and MDC cytokines for PFS, and eotaxin-3, NT-3, and CKβ8-1 for OS, were shown to be predictive biomarkers for nab-paclitaxel and gemcitabine regimen. Similarly, oncostatin, BDNF, and IP10 cytokines were proven to act as predictive biomarkers regarding PFS, for FOLFIRINOX regimen. In the resectable cohort, RANTES, TIMP-1, FGF-4, and IL-10 individually differentiated patients according to their cancer-associated survival. Regarding immune cell populations, baseline high levels of circulating B lymphocytes were related to a significantly longer OS, while these levels significantly decreased as progression occurred. Similarly, baseline high levels of helper lymphocytes (CD4+), low levels of cytotoxic lymphocytes (CD8+), and a high CD4/CD8 ratio, were related to a significantly longer PFS. Finally, high levels of CD4+ and CD8+ intratumoural infiltration was associated with significantly longer PFS. In conclusion, in this study we were able to identify several prognostic and predictive biomarker candidates in patients diagnosed of resectable or BL PDAC.

Neoadjuvant chemotherapy drives intratumoral T cells toward a proinflammatory profile in pancreatic cancer

BACKGROUNDPancreatic ductal adenocarcinoma (PDAC) has a dismal prognosis. At diagnosis, only 20% of patients with PDAC are eligible for primary resection. Neoadjuvant chemotherapy can enable surgical resection in 30%-40% of patients with locally advanced and borderline resectable PDAC. The effects of neoadjuvant chemotherapy on the cytokine production of tumor-infiltrating T cells are unknown in PDAC.METHODSWe performed multiplex immunofluorescence to investigate T cell infiltration in 91 patients with PDAC. Using flow cytometry, we analyzed tumor and matched blood samples from 71 patients with PDAC and determined the frequencies of T cell subsets and their cytokine profiles. Both cohorts included patients who underwent primary resection and patients who received neoadjuvant chemotherapy followed by surgical resection.RESULTSIn human PDAC, T cells were particularly enriched within the tumor stroma. Neoadjuvant chemotherapy markedly enhanced T cell density within the ductal area of the tumor. Whereas infiltration of cytotoxic CD8+ T cells was unaffected by neoadjuvant chemotherapy, the frequency of conventional CD4+ T cells was increased, and the proportion of Tregs was reduced in the pancreatic tumor microenvironment after neoadjuvant treatment. Moreover, neoadjuvant chemotherapy increased the production of proinflammatory cytokines by tumor-infiltrating T cells, with enhanced TNF-α and IL-2 and reduced IL-4 and IL-10 expression.CONCLUSIONNeoadjuvant chemotherapy drives intratumoral T cells toward a proinflammatory profile. Combinational treatment strategies incorporating immunotherapy in neoadjuvant regimens may unleash more effective antitumor responses and improve prognosis of pancreatic cancer.FUNDINGThis work was supported by the Jung Foundation for Science and Research, the Monika Kutzner Foundation, the German Research Foundation (SE2980/5-1), the German Cancer Consortium, and the Faculty of Medicine Carl Gustav Carus, Technische Universität Dresden.

Circulating CD8+CD122+ T cells as a prognostic indicator of pancreatic cancer

Purpose

The distribution of tissue infiltrating lymphocytes has been shown to affect the prognosis of patients with pancreatic cancer in some previous studies. However, the role of peripheral lymphocytes in pancreatic cancer remains debated. The purpose of this study was to analyze the peripheral subtypes of T lymphocytes, and establish their association with the prognosis of patients with pancreatic cancer.

Methods

Blood and tissue samples were collected from patients with metastatic pancreatic cancer (n = 54), resectable pancreatic cancer (n = 12), and benign pancreatic cysts (n = 52) between April 2019 and January 2022 and analyzed.

Results

Patients with metastatic pancreatic cancer had a larger proportion of both tumor-suppressive and tumor-promoting cells than those with benign pancreatic cysts. In addition, the proportion of peripheral CD4+ T cells positively correlated with the survival of patients with metastatic pancreatic cancer, and the proportion of peripheral CD8+CD122+ T cells was associated with early mortality (< 90 days). After chemotherapy, CD8+CD122+ T cells decreased in patients who had a partial response or stable disease. Moreover, by analyzing resected specimens, we first proved that the existence of CD8+CD122+ T cells in a tumor microenvironment (TME) depends on their proportion in peripheral blood.

Conclusion

Circulating CD8+CD122+ T cells can be a prognostic indicator in patients with pancreatic cancer.

Neoadjuvant therapy alters the immune microenvironment in pancreatic cancer

Pancreatic cancer has an exclusive inhibitory tumor microenvironment characterized by a dense mechanical barrier, profound infiltration of immunosuppressive cells, and a lack of penetration of effector T cells, which constitute an important cause for recurrence and metastasis, resistance to chemotherapy, and insensitivity to immunotherapy. Neoadjuvant therapy has been widely used in clinical practice due to its many benefits, including the ability to improve the R0 resection rate, eliminate tumor cell micrometastases, and identify highly malignant tumors that may not benefit from surgery. In this review, we summarize multiple aspects of the effect of neoadjuvant therapy on the immune microenvironment of pancreatic cancer, discuss possible mechanisms by which these changes occur, and generalize the theoretical basis of neoadjuvant chemoradiotherapy combined with immunotherapy, providing support for the development of more effective combination therapeutic strategies to induce potent immune responses to tumors.

Advance of T regulatory cells in tumor microenvironment remodeling and immunotherapy in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is highly aggressive, deadly, and is rarely diagnosed early. Regulatory T cells (Treg) are a multifunctional class of immunosuppressive T cells that help maintain immunologic homeostasis and participate in autoimmune diseases, transplants, and tumors. This cell type mediates immune homeostasis, tolerance, and surveillance and is associated with poor outcomes in PDAC. Tregs remodel the tumor immune microenvironment, mediate tumor immune escape, and promote tumor invasion and metastasis. A promising area of research involves regulating Tregs to reduce their infiltration into tumor tissues. However, the complexity of the immune microenvironment has limited the efficacy of immunotherapy in PDAC. Treg modulation combined with other treatments is emerging. This review summarizes the mechanisms of Tregs activity in tumor immune microenvironments in PDAC and the latest developments in immunotherapy and clinical trials.

Tumor immune-gene expression profiles and peripheral immune phenotypes associated with clinical outcomes of locally advanced pancreatic cancer following FOLFIRINOX

Background

A comprehensive analysis of peripheral immune cell phenotypes and tumor immune-gene expression profiles in locally advanced pancreatic cancer patients treated with neoadjuvant chemotherapy in a phase II clinical trial was carried out.

Methods

Patients were treated with neoadjuvant modified folinic acid, fluorouracil, irinotecan hydrochloride, oxaliplatin (mFOLFIRINOX) followed by surgery and adjuvant gemcitabine at the Asan Medical Center. Correlations between survival outcomes and baseline peripheral immune cells and their changes during preoperative chemotherapy were analyzed. Patients who had surgery were divided into two groups according to achievement of disease-free survival >10 months (achieved versus failed). Differential expression and pathway analysis of immune-related genes were carried out using the Nanostring platform, and immune cells within the tumor microenvironment were compared by immunohistochemistry.

Results

Forty-four patients were treated in the phase II clinical trial. Higher baseline CD14+CD11c+HLA-DR+ monocytes (P = 0.044) and lower Foxp3+CD4+ T cells (P = 0.02) were associated with poor progression-free survival of neoadjuvant mFOLFIRINOX. During the preoperative chemotherapy, PD-1 T cells significantly decreased (P = 0.0110). Differential expression and pathway analysis of immune-genes from the resected tumor after neoadjuvant treatment revealed transforming growth factor-β pathway enrichment and higher expression of MARCO (adjusted P < 0.05) associated with early recurrence. Enrichment of the Th1 pathway and higher peritumoral CD8+ T cells (P = 0.0103) were associated with durable disease-free survival from surgery (>10 months) following neoadjuvant mFOLFIRINOX.

Conclusions

Our results identify potential immune biomarkers for locally advanced pancreatic cancer and provide insights into pancreatic cancer immunity.

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We performed immune profiling of locally advanced pancreatic cancer treated with neoadjuvant therapy in a phase II trial.

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Proportion of programmed cell death protein 1-expressing peripheral CD8+ cells decreased after neoadjuvant chemotherapy.

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Lower peripheral monocytes and higher regulatory T cells were associated with better progression-free survival.

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Th1 pathway and higher peritumoral CD8+ T cells were associated with longer disease-free survival from surgery.

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Transforming growth factor-β pathway and higher MARCO expression were associated with early recurrence after surgery.

Neoadjuvant chemoradiation alters the immune microenvironment in pancreatic ductal adenocarcinoma

Patients with pancreatic ductal adenocarcinoma (PDAC) have a grim prognosis despite complete surgical resection and intense systemic therapies. While immunotherapies have been beneficial with many different types of solid tumors, they have almost uniformly failed in the treatment of PDAC. Understanding how therapies affect the tumor immune microenvironment (TIME) can provide insights for the development of strategies to treat PDAC. We used quantitative multiplexed immunofluorescence (qmIF) quantitative spatial analysis (qSA), and immunogenomic (IG) analysis to analyze formalin-fixed paraffin embedded (FFPE) primary tumor specimens from 44 patients with PDAC including 18 treated with neoadjuvant chemoradiation (CRT) and 26 patients receiving no treatment (NT) and compared them with tissues from 40 treatment-naïve melanoma patients. We find that relative to NT tumors, CD3+ T cell infiltration was increased in CRT treated tumors (p = .0006), including increases in CD3+CD8+ cytotoxic T cells (CTLs, p = .0079), CD3+CD4+FOXP3- T helper cells (Th, p = .0010), and CD3+CD4+FOXP3+ regulatory T cells (Tregs, p = .0089) with no difference in CD68+ macrophages. IG analysis from micro-dissected tissues indicated overexpression of genes involved in antigen presentation, T cell activation, and inflammation in CRT treated tumors. Among treated patients, a higher ratio of Tregs to total T cells was associated with shorter survival time (p = .0121). Despite comparable levels of infiltrating T cells in CRT PDACs to melanoma, PDACs displayed distinct spatial profiles with less T cell clustering as defined by nearest neighbor analysis (p < .001). These findings demonstrate that, while CRT can achieve high T cell densities in PDAC compared to melanoma, phenotype and spatial organization of T cells may limit benefit of T cell infiltration in this immunotherapy-resistant tumor.

Modulation of Type I Interferon Responses to Influence Tumor-Immune Cross Talk in PDAC

Immunotherapy has revolutionized the treatment of many cancer types. However, pancreatic ductal adenocarcinomas (PDACs) exhibit poor responses to immune checkpoint inhibitors with immunotherapy-based trials not generating convincing clinical activity. PDAC tumors often have low infiltration of tumor CD8+ T cells and a highly immunosuppressive microenvironment. These features classify PDAC as immunologically "cold." However, the presence of tumor T cells is a favorable prognostic feature in PDAC. Intrinsic tumor cell properties govern interactions with the immune system. Alterations in tumor DNA such as genomic instability, high tumor mutation burden, and/or defects in DNA damage repair are associated with responses to both immunotherapy and chemotherapy. Cytotoxic or metabolic stress produced by radiation and/or chemotherapy can act as potent immune triggers and prime immune responses. Damage- or stress-mediated activation of nucleic acid-sensing pathways triggers type I interferon (IFN-I) responses that activate innate immune cells and natural killer cells, promote maturation of dendritic cells, and stimulate adaptive immunity. While PDAC exhibits intrinsic features that have the potential to engage immune cells, particularly following chemotherapy, these immune-sensing mechanisms are ineffective. Understanding where defects in innate immune triggers render the PDAC tumor-immune interface less effective, or how T-cell function is suppressed will help develop more effective treatments and harness the immune system for durable outcomes. This review will focus on the pivotal role played by IFN-I in promoting tumor cell-immune cell cross talk in PDAC. We will discuss how PDAC tumor cells bypass IFN-I signaling pathways and explore how these pathways can be co-opted or re-engaged to enhance the therapeutic outcome.

Baseline immunity predicts prognosis of pancreatic cancer patients treated with WT1 and/or MUC1 peptide-loaded dendritic cell vaccination and a standard chemotherapy

The prognosis of patients with advanced pancreatic cancer is poor despite the recent introduction of immune checkpoint inhibitors. Therefore, the development of new therapeutic approaches is urgently required. In the present phase I/II study, we have evaluated the safety, the efficacy and the prognostic factors of Wilms' tumor 1 (WT1) and/or mucin 1 (MUC1) peptide-loaded dendritic cell (DC) vaccination in combination with a chemotherapy employing gemcitabine plus nab-paclitaxel or a combination chemotherapy regimen consisting of oxaliplatin, irinotecan, fluorouracil and leucovorin (FOLFIRINOX) in patients with advanced or relapsed pancreatic ductal adenocarcinoma (PDAC). Forty-eight eligible patients were enrolled and received the vaccinations approximately every 2-4 weeks at least seven times. No severe adverse events related to the vaccinations were observed. Median progression free survival and overall survival were 8.1 months and 15.1 months, respectively. DC vaccinations augmented tumor specific immunity which might be related to clinical outcome. The multivariate analyses demonstrated that WT1 or MUC1-specific interferonɤ enzyme-linked immunospot number prior to DC vaccination was an independent prognostic factor related to overall survival. These results indicate that DC-based immunotherapy combined with a conventional chemotherapy is safe and has clinical benefits for patients in advanced stage of PDAC. The precise evaluation of the baseline antitumor specific immunity is critical to predict clinical outcome.

The tumor microenvironment in pancreatic ductal adenocarcinoma: current perspectives and future directions

Pancreatic ductal adenocarcinoma (PDAC) is among the most lethal malignancies and is characterized by a unique tumor microenvironment (TME) consisting of an abundant stromal component. Many features contained with the PDAC stroma contribute to resistance to cytotoxic and immunotherapeutic regimens, as well as the propensity for this tumor to metastasize. At the cellular level, PDAC cells crosstalk with a complex mixture of non-neoplastic cell types including fibroblasts, endothelial cells, and immune cells. These intricate interactions fuel the progression and therapeutic resistance of this aggressive cancer. Moreover, data suggest the polarization of these cell types, in particular immune and fibroblast populations, dictate how PDAC tumors grow, metastasize, and respond to therapy. As a result, current research is focused on how to best target these populations to render tumors responsive to treatment. Herein, we summarize the cell populations implicated in providing a supporting role for the development and progression of PDAC. We focus on stromal fibroblasts and immune subsets that have been widely researched. We discuss factors which govern the phenotype of these populations and provide insight on how they have been targeted therapeutically. This review provides an overview of the tumor microenvironment and postulates that cellular and soluble factors within the microenvironment can be specifically targeted to improve patient outcomes.

Changes of proportions of circulating lymphocyte subsets in cancer patients after chemotherapy

BACKGROUND

It remains unknown how chemotherapy affects circulating lymphocyte subsets and whether the pattern of change is related to prognosis in cancer patients.

METHODS

Cancer patients who received chemotherapy between 2018/03/01 and 2019/12/31 were enrolled from the Hefei Cancer Hospital, Chinese Academy of Sciences. Peripheral blood samples were collected before and 3 weeks after the start of chemotherapy, and the proportions of T cells (CD3+), helper T cells (CD3+CD4+), cytotoxic T cells (CD3+CD8+), B cells (CD19+), and Natural killer (NK) cells (CD3-CD56+) were examined by flow cytometry. Multivariable logistic regression analysis was employed to explore risk factors associated with overall survival within 12 months after the start of chemotherapy.

RESULTS

A total of 167 patients with cancer were included in the analysis, including 14 cases of cervical cancer, 18 cases of breast cancer, 33 cases of gastric cancer, 48 cases of lung cancer, 21 cases of colorectal cancer, and 33 cases of esophageal cancer. The proportion of T cells (72.58%±10.44% vs. 80.67%±11.63%, P<0.001) and cytotoxic T cells (25.38%±8.87% vs. 39.20%±12.26%, P<0.001) significantly increased, while the proportion of helper T cells (45.58%±10.19% vs. 41.98%±10.47%, P<0.001), B cells (15.10%±5.23% vs. 11.29%±5.60%, P<0.001), and NK cells (19.33%±7.54% vs. 18.28%±7.62%, P<0.001) significantly decreased at 3 weeks after chemotherapy when compared to baseline levels. The overall mortality rate was 14.97% (25/167) within 1 year after the start of chemotherapy. Patients who survived showed a significantly less increase in cytotoxic T cells (13.38%±8.28% vs. 17.28%±7.97%, P=0.030) and less decrease in B cells (-3.58%±2.81% vs. -5.29%±3.03%, P=0.006) when compared to non-survivors. Greater decreases in helper T cells (OR 0.81, 95% CI, 0.68-0.96) and B cells (OR 0.72, 95% CI, 0.59-0.87), and a greater increase in cytotoxic T cells (OR 1.09, 95% CI, 1.03-1.16) were risk factors for poor overall survival.

CONCLUSIONS

Circulating lymphocyte subsets of cancer patients presented characteristic changes after chemotherapy. Patients with a greater decrease in helper T cells and B cells, or greater increase in cytotoxic T cells, may have worse survival.

Circulating Immunological Biomarkers: Prognosis of Pancreatic Cancer Patients Reflected by the Immune System

ABSTRACT

To date, little advances have been made toward new and more effective therapies for pancreatic ductal adenocarcinoma (PDAC). Discovery of prognostic and predictive biomarkers is needed to stratify patients for available treatments and to elucidate how new therapies could be developed. Recent studies have made clear that the immune system is not only affected in the microenvironment of the primary tumor and it is also systemically disrupted in PDAC patients. Under normal circumstances, the immune system is in perfect balance with both proinflammatory and anti-inflammatory components present. In this review, we focus on circulating immunological characteristics including immune cells and their subtypes, cytokines, and immune checkpoints in the peripheral blood not only to understand the poor prognosis of PDAC patients but also to find new leads for new innovative therapies.

Tumor Microenvironment Immune Response in Pancreatic Ductal Adenocarcinoma Patients Treated With Neoadjuvant Therapy

BACKGROUND

Neoadjuvant folinic acid, fluorouracil, irinotecan, and oxaliplatin (FOLFIRINOX) and chemoradiation have been used to downstage borderline and locally advanced pancreatic ductal adenocarcinoma (PDAC). Whether neoadjuvant therapy-induced tumor immune response contributes to the improved survival is unknown. Therefore, we evaluated whether neoadjuvant therapy induces an immune response towards PDAC.

METHODS

Clinicopathological variables were collected for surgically resected PDACs at the Massachusetts General Hospital (1998-2016). Neoadjuvant regimens included FOLFIRINOX with or without chemoradiation, proton chemoradiation (25 Gy), photon chemoradiation (50.4 Gy), or no neoadjuvant therapy. Human leukocyte antigen (HLA) class I and II expression and immune cell infiltration (CD4+, FoxP3+, CD8+, granzyme B+ cells, and M2 macrophages) were analyzed immunohistochemically and correlated with clinicopathologic variables. The antitumor immune response was compared among neoadjuvant therapy regimens. All statistical tests were 2-sided.

RESULTS

Two hundred forty-eight PDAC patients were included. The median age was 64 years and 50.0% were female. HLA-A defects were less frequent in the FOLFIRINOX cohort (P = .006). HLA class II expression was lowest in photon and highest in proton patients (P = .02). The FOLFIRINOX cohort exhibited the densest CD8+ cell infiltration (P < .001). FOLFIRINOX and proton patients had the highest CD4+ and lowest T regulatory (FoxP3+) cell density, respectively. M2 macrophage density was statistically significantly higher in the treatment-naïve group (P < .001) in which dense M2 macrophage infiltration was an independent predictor of poor overall survival.

CONCLUSIONS

Neoadjuvant FOLFIRINOX with or without chemoradiation may induce immunologically relevant changes in the tumor microenvironment. It may reduce HLA-A defects, increase CD8+ cell density, and decrease T regulatory cell and M2 macrophage density. Therefore, neoadjuvant FOLFIRINOX therapy may benefit from combinations with checkpoint inhibitors, which can enhance patients' antitumor immune response.

Dendritic cell vaccination combined with a conventional chemotherapy for patients with relapsed or advanced pancreatic ductal adenocarcinoma: a single-center phase I/II trial

The prognosis of patients with advanced pancreatic cancer is poor. In the present phase I/II study, we have evaluated the safety and the feasibility of Wilms' tumor 1 (WT1) and/or mucin1 (MUC1) peptide-pulsed dendritic cell (DC) vaccination in combination with chemotherapy in patients with advanced or relapsed pancreatic ductal adenocarcinoma (PDAC). Sixty-five eligible patients were enrolled. No severe adverse events related to the vaccinations were observed. Objective response rate and disease control rate was 12.3% and 50.8%, respectively. Median progression-free survival and overall survival were 4.9 and 9.6 months, respectively. DC vaccinations augmented WT1- and MUC1-specific immunity which might be related to clinical outcome. These results indicate that DC-based immunotherapy combined with a conventional chemotherapy is safe and feasible for patients in advanced stage of PDAC.

Heme Oxygenase-1 Inhibition Potentiates the Effects of Nab-Paclitaxel-Gemcitabine and Modulates the Tumor Microenvironment in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive malignancy with a poor prognosis. Tumor hypoxia plays an active role in promoting tumor progression, malignancy, and resistance to therapy in PDAC. We present evidence that nab-paclitaxel-gemcitabine (NPG) and/or a hypoxic tumor microenvironment (TME) up-regulate heme oxygenase-1 (HO-1), providing a survival advantage for tumors. Using PDAC cells in vitro and a PDAC mouse model, we found that NPG chemotherapy up-regulated expression of HO-1 in PDAC cells and increased its nuclear translocation. Inhibition of HO-1 with ZnPP and SnPP sensitized PDAC cells to NPG-induced cytotoxicity (p < 0.05) and increased apoptosis (p < 0.05). Additionally, HO-1 expression was increased in gemcitabine-resistant PDAC cells (p < 0.05), and HO-1 inhibition increased GEM-resistant PDAC sensitivity to NPG (p < 0.05). NPG combined with HO-1 inhibitor inhibited tumor size in an orthotopic model. In parallel, HO-1 inhibition abrogated the influx of macrophages and FoxP3+ cells, while increasing the proportion of CD8+ infiltration in the pancreatic tumors. These effects were mediated primarily by reducing expression of the immunosuppressive cytokine IL-10.

Alterations in regulatory T cells and immune checkpoint molecules in pancreatic cancer patients receiving FOLFIRINOX or gemcitabine plus nab-paclitaxel

Purpose

This pilot study aimed on generating insight on alterations in circulating immune cells during the use of FOLFIRINOX and gemcitabine/nab-paclitaxel in pancreatic ductal adenocarcinoma (PDAC).

Patients and methods

Peripheral blood mononuclear cells were isolated before and 30 days after initiation of chemotherapy from 20 patients with advanced PDAC. Regulatory T cells (FoxP3+) and immune checkpoints (PD-1 and TIM-3) were analyzed by flow cytometry and immunological changes were correlated with clinical outcome.

Results

Heterogeneous changes during chemotherapy were observed in circulating T-cell subpopulations with a pronounced effect on PD-1+ CD4+/CD8+ T cells. An increase in FoxP3+ or PD-1+ T cells had no significant effect on survival. An increase in TIM3+/CD8+ (but not TIM3+/CD4+) T cells was associated with a significant inferior outcome: median progression-free survival in the subgroup with an increase of TIM-3+/CD8+ T cells was 6.0 compared to 14.0 months in patients with a decrease/no change (p = 0.026); corresponding median overall survival was 13.0 and 20.0 months (p = 0.011), respectively.

Conclusions

Chemotherapy with FOLFIRNOX or gemcitabine/nab-paclitaxel induces variable changes in circulating T-cell populations that may provide prognostic information in PDAC.

A Phase 2 Randomized Placebo-Controlled Adjuvant Trial of GI-4000, a Recombinant Yeast Expressing Mutated RAS Proteins in Patients with Resected Pancreas Cancer

Purpose: GI-4000, a series of recombinant yeast expressing four different mutated RAS proteins, was evaluated in subjects with resected ras-mutated pancreas cancer. Methods: Subjects (n = 176) received GI-4000 or placebo plus gemcitabine. Subjects' tumors were genotyped to identify which matched GI-4000 product to administer. Immune responses were measured by interferon-γ (IFNγ) ELISpot assay and by regulatory T cell (Treg) frequencies on treatment. Pretreatment plasma was retrospectively analyzed by matrix-assisted laser desorption/ionization-time-of-flight (MALDI-ToF) mass spectrometry for proteomic signatures predictive of GI-4000 responsiveness. Results: GI-4000 was well tolerated, with comparable safety findings between treatment groups. The GI-4000 group showed a similar pattern of median recurrence-free and overall survival (OS) compared with placebo. For the prospectively defined and stratified R1 resection subgroup, there was a trend in 1 year OS (72% vs. 56%), an improvement in OS (523.5 vs. 443.5 days [hazard ratio (HR) = 1.06 [confidence interval (CI): 0.53-2.13], p = 0.872), and increased frequency of immune responders (40% vs. 8%; p = 0.062) for GI-4000 versus placebo and a 159-day improvement in OS for R1 GI-4000 immune responders versus placebo (p = 0.810). For R0 resection subjects, no increases in IFNγ responses in GI-4000-treated subjects were observed. A higher frequency of R0/R1 subjects with a reduction in Tregs (CD4⁺/CD45RA⁺/Foxp3^low) was observed in GI-4000-treated subjects versus placebo (p = 0.033). A proteomic signature was identified that predicted response to GI-4000/gemcitabine regardless of resection status. Conclusion: These results justify continued investigation of GI-4000 in studies stratified for likely responders or in combination with immune check-point inhibitors or other immunomodulators, which may provide optimal reactivation of antitumor immunity. ClinicalTrials.gov Number: NCT00300950.

CXCL10 is a Tumor Microenvironment and Immune Infiltration Related Prognostic Biomarker in Pancreatic Adenocarcinoma

Pancreatic adenocarcinoma (PAAD) is the 10th most common cancer worldwide and the outcomes for patients with the disease remain extremely poor. Precision biomarkers are urgently needed to increase the efficiency of early diagnosis and to improve the prognosis of patients. The tumor microenvironment (TME) and tumor immune infiltration are thought to impact the occurrence, progression, and prognosis of PAAD. Novel biomarkers excavated originating from the TME and immune infiltration may be effective in predicting the prognosis of PAAD patients. In the current study, the ESTIMATE and CIBERSORT algorithms were applied to estimate the division of immune and stromal components and the proportion of tumor-infiltrating immune cells in 182 PAAD cases downloaded from The Cancer Genome Atlas database. Intersection analyses of the Protein-Protein Interaction networks and Cox regression analysis identified the chemokine (CXC-motif) ligand 10 (CXCL10) as a predictive biomarker. We verified that CXCL10 in the TME negatively correlates with prognosis in PAAD and positively correlates with tumor cell differentiation. GSE62452 from the GEO database and cumulative survival analysis were performed to validate CXCL10 expression as an independent prognostic indicator. We also found that memory B cells, regulatory T cells, and macrophages M0 and M1 were correlated with the expression of CXCL10 indicating that expression of CXCL10 influenced the immune activity of the TME. Our data suggest that CXCL10 is beneficial as a prognostic indicator in PAAD patients and highlights the potential for immune targeted therapy in the treatment of PAAD.

T-Cell Immunity in Pancreatic Cancer

Worldwide, approximately half a million people are diagnosed with pancreatic cancer every year, with mortality rates of more than 90%. T cells within pancreatic tumors are generally infrequent and incapable of eliciting antitumor immunity. Thus, pancreatic cancer is considered an "immunologically cold" tumor. However, recent studies clearly show that when T-cell immunity in pancreatic cancer is sufficiently induced, T cells become effective weapons. This fact suggests that to improve pancreatic cancer patients' clinical outcomes, we need to unveil the complex immune biology of this disease. In this review, we discuss the elements of tumor immunogenicity in the specific context of pancreatic malignancy.

Effect of Octreotide Long-Acting Release on Tregs and MDSC Cells in Neuroendocrine Tumour Patients: A Pivotal Prospective Study

Octreotide long-acting repeatable (LAR) is largely used to treat functional and/or metastatic neuroendocrine neoplasms (NENs). Its effect in controlling carcinoid syndrome and partially reduce tumour burden is attributable to the ability of octreotide to bind somatostatin receptors (SSTRs) on the tumour and metastasis, regulating growth hormone secretion and cell growth. Notably, SSTRs are also expressed, at different levels, on Tregs. Tregs, together with myeloid-derived suppressor cells (MDSCs), are key components in the anti-tumour immunoregulation. This is the first prospective study aimed to explore the impact of Octreotide (OCT) LAR on the immune system, with a particular focus on Tregs and MDSC cells. Here, we show that circulating Tregs are elevated in NENs patients compared to healthy donors and that treatment with OCT LAR significantly decrease the level of total Tregs and of the three functional Tregs populations: nTregs, eTregs and non-Tregs. Furthermore, OCT LAR treatment induces a functional impairment of the remaining circulating Tregs, significantly decreasing the expression of PD1, CTLA4 and ENTPD1. A trend in circulating MDSC cells is reported in patients treated with OCT LAR. The results reported here suggest that the effect of OCT LAR on Tregs could tip the balance of the patients' immune-system towards a durable anti-tumour immunosurveillance with consequent long-term control of the NENs disease.

FoxP3+ T regulatory cells in cancer: Prognostic biomarkers and therapeutic targets

T Regulatory cells (Tregs) can have both protective and pathological roles. They maintain immune homeostasis and inhibit immune responses in various diseases, including cancer. Proportions of Tregs in the peripheral blood of some cancer patients increase by approximately two-fold, compared to those in healthy individuals. Tregs contribute to cancer development and progression by suppressing T effector cell functions, thereby compromising tumor killing and promoting tumor growth. Highly immunosuppressive Tregs express upregulated levels of the transcription factor, Forkhead box protein P3 (FoxP3). Elevated levels of FoxP3⁺ Tregs within the tumor microenvironment (TME) showed a positive correlation with poor prognosis in various cancer patients. Despite the success of immunotherapy, including the use of immune checkpoint inhibitors, a significant proportion of patients show low response rates as a result of primary or acquired resistance against therapy. Some of the mechanisms which underlie the development of therapy resistance are associated with Treg suppressive function. In this review, we describe Treg contribution to cancer development/progression, and the mechanisms of Treg-mediated immunosuppression. We discuss the prognostic significance of FoxP3⁺ Tregs in different cancers and their potential use as prognostic biomarkers. We also describe potential therapeutic strategies to target Tregs in combination with other types of immunotherapies aiming to overcome tumor resistance and improve clinical outcomes in cancer patients. Overall, understanding the prognostic significance of FoxP3⁺ Tregs in various cancers and their contribution to therapy resistance could help in the development of more effective targeted therapeutic strategies to enhance the clinical outcomes in cancer patients.

Role of CD25 expression on prognosis of acute myeloid leukemia: A literature review and meta-analysis

The gene expression for interleukin-2 receptor subunit alpha (CD25/IL2RA) is frequently altered in adults with acute myeloid leukemia (AML). Increasing evidence indicates that the elevated expression of CD25 may be correlated with poor survival for AML patients. Thus, we performed this meta-analysis to further evaluate the prognostic value of elevated CD25 in AML. Eligible studies were gathered by searching on PubMed, Web of Science, and Embase. Using the R language 3.6.0 software, Pooled hazard ratios (HRs) with their corresponding 95% confidence intervals (CIs) of overall survival (OS) and disease-free survival (DFS)/relapse-free survival (RFS)/event-free survival (EFS) for total and subgroup analyses were calculated to investigate the association of elevated CD25 and outcomes of AML patients. Ten studies with a total of 1640 participants were enrolled in this meta-analysis. Pooled HRs suggested that overexpression of CD25 predicted poor outcomes on both OS (HR = 2.27, 95%CI 1.95–2.64) and DFS/RFS/EFS (HR = 1.77, 95%CI 1.44–2.17) in overall population. Subgroup analyses stratified by ethnicity, AML subtype, cut-off value, statistical methodologies and detection method draw similar results. Our meta-analysis indicates that elevated CD25 expression is a poor prognostic factor for AML patients. Considering limited number of samples, further relevant studies are warranted.

Circulating cells and exosomes in acute myelogenous leukemia and their role in disease progression and survival

Acute myelogenous leukemia (AML) is an aggressive hematological malignancy associated with high rates of mortality. This incidence is due to the complexity in which the AML cells interact with other healthy human cells. These phenomena create an environment that favors the expansion of leukemic cells, which will affect the patient's prognosis. An important aspect is the ability of AML cells to evade immune responses via targeting and signaling immune cells to suppress anti-tumor responses. Many studies have reported that associations among components in the peripheral bloodstream might modulate leukemic progression because AML survival is a fundamental step for recolonizing bone marrow after allogeneic hematopoietic stem cell (HSC) transplantation or chemotherapy. Therefore, we collected the most important data about components that circulate with leukemic blasts and contribute to their survival and proliferation. We also discuss clinical approaches that could be conducted to more effectively treat the disease.

Kras mutation correlating with circulating regulatory T cells predicts the prognosis of advanced pancreatic cancer patients

Purpose

Kras mutation and abnormal immune status are associated with pancreatic cancer development and progression. In this study, we evaluated the Kras mutation status in circulating tumor DNA and circulating T cell subsets in a cohort of advanced pancreatic cancer patients.

Methods

Samples were retrospectively obtained from a series of 210 pathological advanced pancreatic cancer patients between 2012 and 2014. The Kras mutation status was detected in cell‐free circulating tumor DNA (ctDNA) by ddPCR and circulating T cell subsets were analyzed by flow cytometry.

Results

Univariate analysis found that tumor node metastasis (TNM) stage, chemotherapy, circulating regulatory T cells, CA19‐9 levels, CA125 levels, and Kras^G12D and Kras^G12V mutations were significantly related to overall survival in advanced pancreatic cancer patients. Multivariate analysis identified that TNM stage (P = .03, HR:1.422), Tregs (P = .004, HR:1.522), CA19‐9 levels (P = .009, HR:1.488), Kras^G12D mutation (P = .044, HR:1.353), and Kras^G12V mutation (P = .001, HR:1.667) were independent prognostic markers. Furthermore, we found that Kras^G12V mutation in ctDNA was correlated with high circulating proportion of Tregs, and patients with both Kras^G12V mutation and high levels of Tregs were associated with extremely poor survival in advanced pancreatic cancer.

Conclusion

Kras^G12V mutation was associated with high circulating regulatory T cell levels, and both of them predicted worse prognosis in advanced pancreatic cancer patients.

Pancreatic Stellate Cells Promote Tumor Progression by Promoting an Immunosuppressive Microenvironment in Murine Models of Pancreatic Cancer

OBJECTIVES

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal forms of cancer with poor prognosis. Pancreatic stellate cells (PSCs) play a vital role in PDAC development. The aim of this study was to explore tumor microenvironment response to PSCs in an orthotopic pancreatic cancer mouse model and to assess if PSCs secreted factors that can facilitate an immunosuppressive microenvironment.

METHODS

Pancreatic ductal adenocarcinoma orthotopic tumor model, derived from coinjection of Panc02 cells plus PSCs, was used to investigate tumor proliferation, metastasis, and the population of immune cells in vivo, including regulatory T cells, M2-type macrophages, myeloid-derived suppressor cells, CD8 T cells, CD4 T cells, M1-type macrophages, natural killer (NK), and NK T cells.

RESULTS

Pancreatic stellate cells promoted PDAC growth not only induced cell proliferation and metastasis, but also significantly increased the suppressive immune cell population of regulatory T cells, M2-type macrophages, and myeloid-derived suppressor cells. In addition, PSCs decreased the immune cell population of CD8 T, CD4 T cells, and M1-type macrophages in the spleen and tumor tissues of the tumor-bearing mice. Moreover, PSCs decreased the population of NK and NK T cells in the tumor tissues.

CONCLUSIONS

Our findings support PSCs playing multiple roles in PDAC development via promoting immunosuppressive microenvironment.

Inhibition of PAK1 suppresses pancreatic cancer by stimulation of anti-tumour immunity through down-regulation of PD-L1

Immunotherapies have not yielded significant clinical benefits for pancreatic ductal adenocarcinoma (PDA) because of the existence of an immunosuppressive tumour microenvironment (TME) characterized by a desmoplastic stroma containing infiltrated immune cells and activated pancreatic stellate cells (PSCs). This study aims to investigate the involvement of PAK1 in anti-tumour immunity. In PDA patients, low PAK1 expression, low activation of PSC and high CD8⁺ T cell/PAK1 ratios correlated with longer overall survival. In a murine PDA model, PAK1 knockout increased intra-tumoral CD4⁺ and CD8⁺ T cells, inhibited PSCs activation and extended survival. Inhibition of PAK1 reduced PSC-stimulated PDA cell proliferation and migration, blocked PSC-mediated protection of PDA cells from killing by cytotoxic lymphocytes and decreased intrinsic and PSC-stimulated PD-L1 expression in PDA cells, which further sensitized PDA cells to cytotoxic lymphocytes. Inhibition of PAK1 stimulates anti-tumour immunity by increasing intra-tumoral CD4⁺ and CD8⁺ T cells, and by sensitizing PDA cells to killing by cytotoxic lymphocytes via down-regulation of intrinsic and PSC-stimulated PD-L1 expression. PAK1 inhibitors, especially in combination with immune checkpoint inhibitors may result in improved efficacy of immunotherapy of PDA.

Real-time prediction of patient immune cell modulation during irreversible electroporation therapy

Immunotherapies have demonstrated limited efficacy in pancreatic ductal adenocarcinoma (PDAC) patients despite their success in treating other tumor types. This limitation is largely due to the relatively immunosuppressive environment surrounding the tumor. A focal ablative technique called irreversible electroporation (IRE) has been shown to modulate this environment, enhancing the efficacy of immunotherapy. One enhancing factor related to improved prognosis is a decrease in regulatory T cells (T_reg). This decrease has been previously unpredictable for clinicians using IRE, who currently have limited real-time metrics for determining the activation of the patient’s immune response. Here, we report that larger overall changes in output current are correlated with larger decreases in T cell populations 24 hours post-treatment. This result suggests that clinicians can make real-time decisions regarding optimal follow-up therapy based on the range of output current delivered during treatment. This capability could maximize the immunomodulating effect of IRE in synergy with follow-up immunotherapy. Additionally, these results suggest that feedback from a preliminary IRE treatment of the local tumor may help inform clinicians regarding the timing and choice of subsequent therapies, such as resection, immunotherapy, chemotherapy, or follow-up thermal or non-thermal ablation.

Outcomes in patients with pancreatic cancer as a secondary malignancy: a retrospective single-institution study

PURPOSE

This study aimed to evaluate the clinicopathological features and oncological outcomes of pancreatic cancer (PC) patients with prior malignancies (2nd primary PC) compared with those of patients without any prior malignancies in their history (1st primary PC).

METHODS

We retrospectively reviewed clinical data from 185 PC patients undergoing surgical resection. Patients were divided into the 1st and 2nd primary PC groups.

RESULTS

Forty-three patients (23.2%) had a history of prior malignancy. The 2nd primary PC group was significantly older than the 1st primary PC group (mean, 72.1 vs. 65.9 years, respectively, P < 0.001) and was more frequently asymptomatic compared to the 1st primary PC group (67.4 vs. 31.0%, respectively, P < 0.001). The tumor size was larger, and extrapancreatic nerve plexus invasion, venous invasion, and lymph node metastasis were more frequently observed in the 1st primary PC group. The rate of adjuvant therapy administration was lower in 2nd primary PC patients (72.5 vs. 51.2%, P = 0.009). In the survival analysis, no significant difference in overall or disease-free survival was found between the two groups (16.8 vs. 16.4 months, P = 0.725, and 8.7 vs. 9.3 months, P = 0.284, respectively).

CONCLUSION

Despite significant surveillance bias, such as earlier detection in 2nd primary PC, the outcomes of patients with 2nd primary PC were comparable to those of patients with 1st primary PC. Further investigation with a larger sample size and matching for patient age and tumor stage in both groups is needed to elucidate the biological features of 2nd primary PC.

The Gastrointestinal Tumor Microenvironment: An Updated Biological and Clinical Perspective

Gastrointestinal cancers are still responsible for high numbers of cancer-related deaths despite advances in therapy. Tumor-associated cells play a key role in tumor biology, by supporting or halting tumor development through the production of extracellular matrix, growth factors, cytokines, and extracellular vesicles. Here, we review the roles of these tumor-associated cells in the initiation, angiogenesis, immune modulation, and resistance to therapy of gastrointestinal cancers. We also discuss novel diagnostic and therapeutic strategies directed at tumor-associated cells and their potential benefits for the survival of these patients.

T Regulatory CD4+CD25+FoxP3+ Lymphocytes in the Peripheral Blood of Left-Sided Colorectal Cancer Patients

Background and objectives: T regulatory lymphocytes (Treg) are one of the subsets of T-lymphocytes involved in the interaction of neoplastic tumors and the host immune system, and they may impair the immune reaction against cancer. It has been shown that Treg are increased in the peripheral blood of patients with various cancers. In colorectal cancer, the prognostic role of Treg remains controversial. Colorectal cancer is a heterogenous disease, with many variations stemming from its primary tumor location. The aim of this study is to analyse the relationship between the amount of Treg in the peripheral blood of patients with left-sided colorectal cancer in various stages of disease and long-term survival. Materials and Methods: A prospective analysis of 94 patients with left-sided colorectal cancer and a group of 21 healthy volunteers was carried out. Treg levels in peripheral blood were analysed using flow cytometry. Results: There was a statistically significant difference between the amount of Treg in the Ist and IInd TNM stages (p = 0.047). The number of Treg in the entire study group was significantly lower than in the control group (p = 0.008) and between patients in stages II and III and the control group (p = 0.003 and p = 0.018). The group of pT3+pT4 patients also had significantly lower Treg counts in their peripheral blood than the control group (p = 0.005). In the entire study group, the level of Treg cells in the peripheral blood had no influence on survival. The analysis of the TNM stage subgroups also showed no difference in survival between patients with “low” and “high” Treg counts. Conclusion: The absolute number of Treg in the peripheral blood of patients with left-sided colorectal cancer was significantly decreased in comparison to healthy controls, especially for patients with stage II+III disease. Treg presence in the peripheral blood had no impact on survival.

IL-17A increases MHC class I expression and promotes T cell activation in papillary thyroid cancer patients with coexistent Hashimoto's thyroiditis

Background

The incidence of coexisting papillary thyroid cancer (PTC) and Hashimoto’s thyroiditis (HT) is increasing. The impact of HT on PTC prognosis and its possible mechanism remains controversial. Interleukin-17A (IL-17A) has been reported to participate in the pathogenesis of multiple autoimmune diseases and cancers. The aim of this study is to investigate the role of IL-17A in PTC with coexistent HT and evaluate the changes in tumor antigenicity.

Methods

Expression of IL-17A and major histocompatibility complex (MHC) class I molecules were compared on PTC tissue samples with or without HT. PTC cell lines K1 and TPC-1 were stimulated with IL-17A and analyzed for MHC class I expression afterwards. Cluster of differentiation (CD) 8⁺T cell activation, production of Interleukin-2 (IL-2) and Interferon-gamma (IFN-γ) as well as the programmed death-1 (PD-1) expression on lymphocytes were assessed by coculture of donor peripheral blood lymphocytes (PBLs) with IL-17A pretreated PTC cells.

Results

Elevated IL-17A and MHC class I expression were observed in PTC tissue samples with coexistent HT. Stimulation of PTC cells with IL-17A effectively increased MHC class I expression in vitro. Coculture of PBLs with IL-17A pretreated PTC cells resulted in enhanced T cell activation (%CD25⁺ of CD3⁺T cells) and increased IL-2 production along with decreased IFN-γ secretion and PD-1 expression of the lymphocytes.

Conclusions

Papillary thyroid cancer with coexisting Hashimoto’s thyroiditis presents elevated MHC class I expression, which may be the result of IL-17A secretion. T cell activation is enhanced in vitro by IL-17A and may provide future utility in PTC immunotherapy.

Electronic supplementary material

The online version of this article (10.1186/s13000-019-0832-2) contains supplementary material, which is available to authorized users.

Pancreatic Tumor Microenvironment Modulation by EphB4-ephrinB2 Inhibition and Radiation Combination

PURPOSE

A driving factor in pancreatic ductal adenocarcinoma (PDAC) treatment resistance is the tumor microenvironment, which is highly immunosuppressive. One potent immunologic adjuvant is radiotherapy. Radiation, however, has also been shown to induce immunosuppressive factors, which can contribute to tumor progression and formation of fibrotic tumor stroma. To capitalize on the immunogenic effects of radiation and obtain a durable tumor response, radiation must be rationally combined with targeted therapies to mitigate the influx of immunosuppressive cells and fibrosis. One such target is ephrinB2, which is overexpressed in PDAC and correlates negatively with prognosis.Experimental Design: On the basis of previous studies of ephrinB2 ligand-EphB4 receptor signaling, we hypothesized that inhibition of ephrinB2-EphB4 combined with radiation can regulate the microenvironment response postradiation, leading to increased tumor control in PDAC. This hypothesis was explored using both cell lines and in vivo human and mouse tumor models.

RESULTS

Our data show this treatment regimen significantly reduces regulatory T-cell, macrophage, and neutrophil infiltration and stromal fibrosis, enhances effector T-cell activation, and decreases tumor growth. Furthermore, our data show that depletion of regulatory T cells in combination with radiation reduces tumor growth and fibrosis.

CONCLUSIONS

These are the first findings to suggest that in PDAC, ephrinB2-EphB4 interaction has a profibrotic, protumorigenic role, presenting a novel and promising therapeutic target.