An increased abundance of tumor-infiltrating regulatory T cells is correlated with the progression and prognosis of pancreatic ductal adenocarcinoma

Regulatory T Cells in the Tumor Microenvironment and Cancer Progression: Role and Therapeutic Targeting

Recent years have seen significant efforts in understanding and modulating the immune response in cancer. In this context, immunosuppressive cells, including regulatory T cells (Tregs) and myeloid-derived suppressor cells (MDSCs), have come under intense investigation for their proposed roles in suppressing tumor-specific immune responses and establishing an immunosuppressive tumor microenvironment, thus enabling tumor immune evasion. Additionally, recent evidence indicates that Tregs comprise diverse and heterogeneous subsets; phenotypically and functionally distinct subsets of tumor-infiltrating Tregs could contribute differently to cancer prognosis and clinical outcomes. Understanding Treg biology in the setting of cancer, and specifically the tumor microenvironment, is important for designing effective cancer therapies. In this review, we critically examine the role of Tregs in the tumor microenvironment and in cancer progression focusing on human studies. We also discuss the impact of current therapeutic modalities on Treg biology and the therapeutic opportunities for targeting Tregs to enhance anti-tumor immune responses and clinical benefits.

Positive effect of HPV status on prognostic value of blood lymphocyte-to-monocyte ratio in advanced cervical carcinoma

Background

This retrospective study aimed to investigate the prognostic significance of pretreatment lymphocyte-to-monocyte ratio (LMR) in locally advanced cervical cancer and its effect on overall survival.

Methods

The usual blood routine test was quantitatively performed to detect LMR. Signal strengths of human papilloma virus (HPV) type DNA in detected cervical cancer samples using hybrid capture 2 were analyzed in relative light units (RLU) compared with 1 pg/mL of HPV type 16 DNA-positive control (RLU/PC) samples. A total of 1.0 RLU/PC (~1 pg/mL) was used as the threshold for a positive result. The HPV-positive specimens were typed using reverse-hybridization line probe assay.

Results

The LMR and HPV DNA were found to be independent prognostic markers for 5-year overall survival (OS) and progression-free survival, respectively. Their joint detection may further enhance the predictive value for OS. In the positive HR (high risk)-HPV DNA status subgroup, LMR had a positive effect on improved OS but not in the non-HR HPV DNA status subgroup.

Conclusions

The LMR and HR-HPV DNA status can be identified as independent prognostic factors. The different influences of LMR in combined chemoradiotherapy on survival may be related to HR-HPV DNA status. The combined detection of LMR and HR-HPV DNA status may contribute to screening prognosis.

Cancer cell-derived IL-1α induces CCL22 and the recruitment of regulatory T cells

In cancer patients, immunosuppression through regulatory T cells (Treg) is a crucial component of tumor immune evasion and contributes to disease progression. Tumor-infiltrating Treg in particular suppress local effector T cell responses and are associated with poor prognosis in tumors such as human pancreatic cancer or hepatocellular carcinoma (HCC). The chemokine CCL22 is known to recruit Treg into the tumor tissue and many types of human tumors are known to express high levels of CCL22. The mechanisms leading to intratumoral secretion of CCL22 are so far unknown. We demonstrate here that intratumoral CCL22 is induced in tumor-infiltrating immune cells through cancer cell-derived interleukin-1 (IL-1α). In pancreatic cancer and HCC, CCL22 is produced by intratumoral dendritic cells, while the cancer cells themselves do not secrete CCL22 in vitro and in vivo. Incubation of human peripheral blood mononuclear cells (PBMC) or murine splenocytes with tumor cells or tumor cell supernatants strongly induced CCL22 secretion in vitro. Tumor cell supernatants contained IL-1 and CCL22 induction in PBMC could be specifically prevented by the IL-1 receptor antagonist anakinra or by transfection of tumor cell lines with IL-1 siRNA, leading to a suppression of Treg migration. In conclusion, we identify here tumor cell-derived IL-1α as a major inducer of the Treg attracting chemokine CCL22 in human cancer cells. Therapeutic blockade of the IL-1 pathway could represent a promising strategy to inhibit tumor-induced immunosuppression.

Regulatory T cells that co-express RORγt and FOXP3 are pro-inflammatory and immunosuppressive and expand in human pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is highly infiltrated by CD4+T cells that express RORγt and IL-17 (TH17). Compelling evidence from the tumor microenvironment suggest that regulatory T cells (Treg) contribute to TH17 mediated inflammation. Concurrently, PDAC patients have elevated levels of pro-inflammatory cytokines that may lead to TH17 associated functional plasticity in Treg. In this study, we investigated the phenotype and functional properties of Treg in patients with PDAC. We report that PDAC patients have elevated frequency of FOXP3+Treg, which exclusively occurred within the FOXP3+RORγt+Treg compartment. The FOXP3+RORγt+Treg retained FOXP3+Treg markers and represented an activated subset. The expression of RORγt in Treg may indicate a phenotypic switch toward TH17 cells. However, the FOXP3+RORγt+Treg produced both TH17 and TH2 associated pro-inflammatory cytokines, which corresponded with elevated TH17 and TH2 immune responses in PDAC patients. Both the FOXP3+Treg and FOXP3+RORγt+Treg from PDAC patients strongly suppressed T cell immune responses, but they had impaired anti-inflammatory properties. We conclude that FOXP3+RORγt+Treg have a dual phenotype with combined pro-inflammatory and immunosuppressive activity, which may be involved in the pathogenesis of PDAC.

The role of exosomes in the pathogenesis of pancreatic ductal adenocarcinoma

Exosomes are small membrane bound vesicles secreted by cancer cells that have a cytosol rich in proteins and nucleic acids which are capable of modulating the phenotype of neighbouring cells which take them up. In this review we explore the mechanisms through which exosomes are able to impact on the pathogenesis of pancreatic ductal cancer through the modulation of tumour formation and development and exploitation of the tumour microenvironment to modulate both the adaptive and innate immune response. In addition we highlight the potential utility of exosomes not only as biomarkers of disease but also as tools to be used in the therapeutic armamentarium against this disease.

A novel multi-drug metronomic chemotherapy significantly delays tumor growth in mice

BACKGROUND

The tumor immunosuppressive microenvironment represents a major obstacle to an effective tumor-specific cellular immune response.

METHODS

In the present study, the counterbalance effect of a novel metronomic chemotherapy protocol on such an immunosuppressive microenvironment was evaluated in a mouse model upon sub-cutaneous ectopic implantation of B16 melanoma cells. The chemotherapy consisted of a novel multi-drug cocktail including taxanes and alkylating agents, administered in a daily metronomic fashion. The newly designed strategy was shown to be safe, well tolerated and significantly efficacious.

RESULTS

Treated animals showed a remarkable delay in tumor growth and prolonged survival as compared to control group. Such an effect was directly correlated with CD4(+) T cell reduction and CD8(+) T cell increase. Furthermore, a significant reduction in the percentage of both CD25(+)FoxP3(+) and CD25(+)CD127(low) regulatory T cell population was found both in the spleens and in the tumor lesions. Finally, the metronomic chemotherapy induced an intrinsic CD8(+) T cell response specific to B16 naturally expressed Trp2 TAA.

CONCLUSION

The novel multi-drug daily metronomic chemotherapy evaluated in the present study was very effective in counterbalancing the immunosuppressive tumor microenvironment. Consequently, the intrinsic anti-tumor T cell immunity could exert its function, targeting specific TAA and significantly containing tumor growth. Overall, the results show that this represents a promising adjuvant approach to significantly enhance efficacy of intrinsic or vaccine-elicited tumor-specific cellular immunity.

Inhibition of HIF-1α by PX-478 enhances the anti-tumor effect of gemcitabine by inducing immunogenic cell death in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is the worst prognoses among all the malignancies. Now, gemcitabine (Gem) is the first line chemotherapeutic drug for advanced pancreatic cancer. However, Gem is usually ineffective to the PDAC because of high degree of drug resistance. Hypoxia and immune suppressive milieu are the best-described hallmarks of PDAC; therefore, we investigated the impact of hypoxia inducible factor-1 (HIF-1) inhibitor, PX-478, in combination with Gem on the induction of immunogenic cell death (ICD). We verified that combined treatment with Gem/PX-478 significantly enhanced the anti-tumor effect and increased proportion of tumor infiltrating T-lymphocytes in Panc02-bearing immune-competent but not in immune-deficient mice. Vaccination using Panc02 cell line treated with single agent or in combination showed significant anti-tumor effects. Pancreatic cell lines treated with Gem and PX-478 can induce an increase in eIF2α phosphorylation was correlated with down-regulation of HIF-1α and elicited exposure of CRT and release of HMGB1 and ATP. Only co-treated cells induced DC maturation/phagocytosis and IFN-γ secretion by cytotoxic T lymphocytes. Altogether, combined treatment with Gem/PX-478 showed significantly inhibition on tumor growth and anti-tumor immunization. We propose that inhibition HIF-1α elicits Gem-induced immune response and eliminates PDAC cells by inducing ICD.

Low intratumoral regulatory T cells and high peritumoral CD8(+) T cells relate to long-term survival in patients with pancreatic ductal adenocarcinoma after pancreatectomy

The prognosis for pancreatic ductal adenocarcinoma (PDAC) remains extremely poor. Recent studies have focused on the role of lymphocytes in the PDAC microenvironment. Using immunohistochemistry, our study explored the clinical significance of intratumoral or peritumoral CD4(+)Foxp3(+) regulatory T cells (Tregs) and CD8(+) T cells in the tumor microenvironment and analyzed their relation to the prognosis of PDAC in a consecutive series of 92 patients after resection. CD8(+) T cells were more frequently seen within peritumoral sites, while CD4(+)Foxp3(+) Tregs were more frequent within intratumoral areas. Neither exhibited any relationship with other clinicopathologic factors. Patients with low levels of intratumoral Tregs had longer disease-free survival than those with higher levels (DFS 22.2 vs. 11.2 months, p < 0.001), and patients with higher levels of peritumoral CD8(+) T cells had longer overall survival than those with lower levels (OS 31.0 vs. 14.2 months, p < 0.001). Multivariate analysis demonstrated that intratumoral Tregs (hazard ratio, HR 3.39, p = 0.010) and peritumoral CD8(+) T cells (HR 0.10, p < 0.001) are related to DFS and OS, respectively. These results indicate that intratumoral Tregs are a negative predictor of DFS, while peritumoral CD8(+) T cells are a positive predictor of OS for PDAC patients with pancreatectomy.

Immunoregulatory Forkhead Box Protein p3-Positive Lymphocytes Are Associated with Overall Survival in Patients with Pancreatic Neuroendocrine Tumors

BACKGROUND

Forkhead box protein p3-positive (FoxP3(+)) regulatory T cells (Tregs) suppress host T-cell-mediated immune responses, limit surveillance against cancers, and have been associated with a poor prognosis.

STUDY DESIGN

This study aims to identify the prognostic significance of FoxP3(+) Tregs in pancreatic neuroendocrine tumors (PNETs). Patients diagnosed with PNETs between 1992 and 2014 (n = 101) were included in this retrospective analysis. Clinical data, histopathology, and expression of FoxP3(+) Tregs and Ki-67 by immunohistochemistry were assessed. The association of these factors with survival was tested by log-rank test and in additional multivariable analysis.

RESULTS

A total of 101 patients were included in this study. Mean age was 58.0 years (range 18 to 87 years) and median tumor size was 25 mm (range 8 to 160 mm). The degree of infiltration of tumor by FoxP3(+) Tregs was graded as 0 (n = 75), 1 (n = 15), or 2 (n = 11). Median follow-up was 50 months (interquartile range 123 months; Q1 = 20 months and Q3 = 123 months). In univariate analyses, patient age older than 57 years, TNM stage III or IV, tumor size >25 mm, Ki-67 labeling index >20, and a high number of FoxP3(+) tumor-infiltrating lymphocytes were significantly associated with poorer overall survival. In multivariable analyses, FoxP3(+) expression score of 2 (hazard ratio = 6.9; 95% CI 1.4-34.4) was the only statistically significant predictor for overall mortality.

CONCLUSIONS

FoxP3(+) Treg expression is an independent prognostic factor in patients with PNETs, associated with statistically significant shorter overall survival. There is a role for additional research into the immune-mediated role of FoxP3(+) Tregs in PNETs.

Macrophages and pancreatic ductal adenocarcinoma

Monocytes and macrophages make up part of the innate immune system and provide one of the first defenses against variety of treats. Macrophages can also modulate the adaptive immune system. Efficient sensing and response to tissue environmental cues highlights the complexity and dynamic nature of macrophages and their plasticity. Macrophages may have divergent roles depending on their polarity and stimulus received. Accumulating evidence demonstrates the critical role played by macrophages in tumor initiation, development, and progression. In this review, we discuss the characteristics of tumor-associated macrophages (TAMs) and their role in pancreatic adenocarcinoma. In addition, we give an overview on recent advances related to the therapeutic implication associated with targeting TAMs in pancreas cancer.

Prognostic Significance of Preoperative Circulating Monocyte Count in Patients With Breast Cancer: Based on a Large Cohort Study

Growing evidence showed that inflammation response plays an important role in cancer development and progression, and absolute lymphocyte count (ALC), absolute monocyte count (AMC), and lymphocyte to monocyte ratio (LMR) have been used as parameters of systemic inflammation in several tumors. In this study, we evaluated the prognostic significance of preoperative ALC, AMC and LMR in breast cancer and 2000 patients between January 2002 and December 2008 at Sun Yat-Sen University Cancer Center were enrolled. Patients were grouped by the cut-off value according to the receiver operating characteristics (ROC) curve analysis. Kaplan-Meier analysis showed that patients with elevated AMC levels (>0.48 × 10/L) had shorter overall survival (OS, P < 0.001). In multivariate analysis, preoperative AMC was identified as an independent prognostic parameter for OS in breast cancer patients (hazard ratio = 1.374, 95% confidence interval: 1.045-1.807). Subgroup analyses revealed that AMC was an unfavorable prognostic factor in stage II-III breast cancer patients and Luminal B, human epithelial growth factor receptor-2 overexpressing subtype, and triple-negative breast cancer (all P < 0.05). Additionally, the prognostic value of ALC and LMR could not be proven in the current study. Preoperative AMC may serve as an easily available and low-priced parameter to predict the outcomes of breast cancer.

The impact of dendritic cell-tumor fusion cells on cancer vaccines - past progress and future strategies

Dendritic cells (DCs) are potent antigen-presenting cells that can be used in cancer vaccines. Thus, various strategies have been developed to deliver tumor-associated antigens via DCs. One strategy includes administering DC-tumor fusion cells (DC-tumor FCs) to induce antitumor immune responses in cancer patients. However, clinical trials using this strategy have fallen short of expectations. Several factors might limit the efficacy of these anticancer vaccines. To induce efficient antitumor immune responses and enhance potential clinical benefits, DC-tumor FC-based cancer vaccines require manipulations that improve immunogenicity for both DCs and whole tumor cells. This review addresses recent progress in improving clinical outcomes using DC-tumor FC-based cancer vaccines.

Perspectives in the treatment of pancreatic adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is an incurable lethal disease whose incidence rate is growing. There is no effective screening for detection of early stage tumors and, in most cases, PDAC is diagnosed at advanced disease stages, when radical pancreatic resection is not possible. The aggressive nature of pancreatic tumor cells lies in the complex genetic mechanisms behind their uncontrolled capability to grow and metastasize, which involve essential adaptive changes in cellular metabolism, signaling, adhesion and immunoediting. In addition, PDAC cells promote a dense functional stroma that facilitates tumor resistance to chemotherapy and radiation. During the last two decades, gemcitabine has been the reference for the systemic treatment of PDAC. However, recently, a regimen combining fluorouracil, irinotecan, oxaliplatin, and leucovorin (FOLFIRINOX) and another combining albumin-bound paclitaxel with gemcitabine have shown clear therapeutic advantage in advanced PDAC, with survival outcomes of 11.3 and 8.5 mo on phase III trials, respectively, over single-agent gemcitabine. With the pending issue of their higher toxicities, these regimens set the reference for ongoing and future clinical studies in advanced PDAC. In addition, the efficacy of oral fluoropyrimidine (S-1) has been well documented in Asiatic PDAC patients. The development of therapeutic approaches other than cytotoxic drugs has proven difficult in the past, with only one drug (erlotinib) approved to date. Besides, a number of agents targeting signaling pathways in tumor or stroma cells are being investigated. Likewise, immunotherapies that target PDAC in various ways are the subject of a number of clinical trials. The search for reliable biomarkers with diagnostic and prognostic value using genomics and mass spectrometry methods may facilitate monitoring and refinement of therapies. This review focuses on current understanding of the pathogenesis of PDAC and the latest developments in the treatment of advanced PDAC.

High expression of sphingosine kinase 1 is associated with poor prognosis in nasopharyngeal carcinoma

It has been reported that sphingosine kinase 1 (SPHK1), an oncogenic enzyme, was involved in the development and progression of a number of human cancers. However, the role of SPHK1 in nasopharyngeal carcinoma (NPC) is largely unknown. The present study aimed to characterize the expression of SPHK1 in human NPC and evaluate its clinical significance. Real-time quantitative reverse transcriptase-polymerase chain reaction (qRT-PCR) and Western blot analyses showed that the expression of SPHK1 mRNA and protein in NPC specimens was significantly higher than that in non-tumorous nasopharyngeal mucosa biopsies. Immunohistochemistry (IHC) was conducted to characterize the expression pattern of SPHK1 in 142 archived paraffin-embedded NPC specimens. Statistical analyses revealed that high levels of SPHK1 expression were associated with the clinical stages, locoregional recurrence and distant metastasis of NPC. NPC patients with high levels of SPHK1 expression had shorter survival time, whereas those with lower levels of SPHK1 expression survived longer. Moreover, multivariate analysis suggested that SPHK1 up-regulation was an independent prognostic factor for NPC. Our results suggest for the first time that SPHK1 is involved in the development and progression of NPC, which can be used as a useful prognostic marker for NPC patients and may be an effective target for treating NPC.

Dendritic cell cancer vaccines: from the bench to the bedside

The recognition that the development of cancer is associated with acquired immunodeficiency, mostly against cancer cells themselves, and understanding pathways inducing this immunosuppression, has led to a tremendous development of new immunological approaches, both vaccines and drugs, which overcome this inhibition. Both "passive" (e.g. strategies relying on the administration of specific T cells) and "active" vaccines (e.g. peptide-directed or whole-cell vaccines) have become attractive immunological approaches, inducing cell death by targeting tumor-associated antigens. Whereas peptide-targeted vaccines are usually directed against a single antigen, whole-cell vaccines (e.g. dendritic cell vaccines) are aimed to induce robust responsiveness by targeting several tumor-related antigens simultaneously. The combination of vaccines with new immuno-stimulating agents which target "immunosuppressive checkpoints" (anti-CTLA-4, PD-1, etc.) is likely to improve and maintain immune response induced by vaccination.

FOXP3+ lymphocyte density in pancreatic cancer correlates with lymph node metastasis

OBJECTIVE

To determine if the density of FOXP3+ lymphocytes in primary tumors and lymph nodes in pancreatic cancer correlates with the presence of lymph node metastases.

METHODS

FOXP3+ lymphocyte density in primary pancreatic cancer tissue and draining lymph nodes was measured using immunohistochemistry. We analyzed the clinical and pathological aspects associated with the accumulation of FOXP3+ lymphocytes in pancreatic cancer. We also analyzed the correlation of density of FOXP3+ lymphocytes in lymph nodes with the nodal status and distance from the primary tumor.

RESULTS

FOXP3+ lymphocyte density in pancreatic cancer was significantly higher than in paratumoral pancreatic tissue. The density of FOXP3+ lymphocytes in local tumor tissue correlated significantly with the histological grade and overall lymph node status. Furthermore, FOXP3+ lymphocyte density was significantly higher in positive lymph nodes than in negative ones, while it had no correlation with the distance of the lymph node from the primary tumor.

CONCLUSION

FOXP3+ lymphocyte density in primary tumor tissue in patients with pancreatic cancer correlates with lymph node metastasis. Lymph nodes containing metastases having higher FOXP3+ lymphocyte densities than do negative lymph nodes.

Prognostic impact of circulating monocytes and lymphocyte-to-monocyte ratio on previously untreated metastatic non-small cell lung cancer patients receiving platinum-based doublet

The link between circulating lymphocyte-to-monocyte ratio (LMR) and newly diagnosed metastatic non-small cell lung cancer (NSCLC) is not fully defined. The study was conducted to evaluate the prognostic impact of LMR on survival outcomes in previously untreated metastatic NSCLC patients receiving platinum-based doublet. Chemotherapy-naive metastatic NSCLC patients undergoing platinum-based doublet were retrospectively enrolled. Clinical features regarding gender, age, Eastern Cooperative Oncology Group (ECOG) performance status, histology, absolute lymphocyte count (ALC), absolute monocyte count (AMC) and LMR were collected to determinate their prognostic impact on progression-free survival (PFS) and overall survival (OS). Up to 370 patients were eligible for the study. By univariate analysis, ECOG performance status, histology, ALC, AMC and LMR were showed to be significantly associated with PFS and OS. In subsequent Cox multivariate analysis, non-squamous cell carcinoma, ALC ≥ 2.45 × 10(9)/L, AMC <0.45 × 10(9)/L and LMR ≥ 4.56 were demonstrated to be independently correlated with better PFS. In addition, independent favorable prognostic factors for OS were only limited to LMR ≥ 4.56 and non-squamous cell carcinoma, whereas ECOG performance status of 2 and AMC ≥ 0.45 × 10(9)/L remained as independently inferior prognostic indicators for OS. Our findings implicate that circulating AMC and LMR are regarded as independent prognostic factors for PFS and OS in previously untreated metastatic NSCLC patients receiving platinum-based doublet.