Pancreatic cancer: role of the immune system in cancer progression and vaccine-based immunotherapy

Modulating pancreatic cancer microenvironment: The efficacy of Huachansu in mouse models via TGF-β/Smad pathway

ETHNOPHARMACOLOGICAL RELEVANCE

Huachansu (HCS) is a traditional Chinese medicine obtained from the dried skin glands of Bufo gargarizans and clinical uses of HCS have been approved in China to treat malignant tumors. The traditional Chinese medicine theory states that HCS relieves patients with cancer by promoting blood circulation to remove blood stasis. Clinical observation found that local injection of HCS given to pancreatic cancer patients can significantly inhibit tumor progression and assist in enhancing the efficacy of chemotherapy. However, the material basis and underlying mechanism have not yet been elucidated.

AIM OF THE STUDY

To investigate the therapeutic potential of HCS for the treatment of pancreatic cancer in in situ transplanted tumor nude mouse model. Furthermore, this study sought to elucidate the molecular mechanisms underlying its efficacy and assess the impact of HCS on the microenvironment of pancreatic cancer. To identify the antitumor effect of HCS in in situ transplanted tumor nude mouse model and determine the Chemopreventive mechanism of HCS on tumor microenvironment (TME).

METHODS

Using the orthotopic transplantation nude mouse model with fluorescently labeled pancreatic cancer cell lines SW1990 and pancreatic stellate cells (PSCs), we examined the effect of HCS on the pancreatic ductal adenocarcinoma (PDAC) microenvironment based on the transforming growth factor β (TGF-β)/Smad pathway. The expression of TGF-β, smad2, smad3, smad4, collagen type-1 genes and proteins in nude mouse model were detected by qRT-PCR and Western blot.

RESULTS

HCS significantly reduced tumor growth rate, increased the survival rate, and ameliorated the histopathological changes in the pancreas. It was found that HCS concentration-dependently reduced the expression of TGF-β1 and collagen type-1 genes and proteins, decreased the expression of Smad2 and Smad3 genes, and downregulated the phosphorylation level of Smad2/3. Additionally, the gene and protein expression of Smad4 were promoted by HCS. Further, the promoting effect gradually enhanced with the rise of HCS concentration.

CONCLUSIONS

The results demonstrated HCS could regulate the activity of the TGF-β/Smad pathway in PDAC, improved the microenvironment of PDAC and delayed tumor progression. This study not only indicated that the protective mechanism of HCS on PDAC might be attributed partly to the inhibition of cytokine production and the TGF-β/Smad pathway, but also provided evidence for HCS as a potential medicine for PDAC treatment.

Immunocyte profiling changes in patients received epidural versus intravenous analgesia after pancreatectomy: A randomized controlled trial

BACKGROUND

Perioperative immunosuppressants, such as surgical stress and opioid use may downregulate anti-cancer immunocytes for patients undergoing pancreatectomy. Thoracic epidural analgesia (TEA) may attenuate these negative effects and provide better anti-cancer immunocyte profile change than intravenous analgesia using opioid.

METHODS

We randomly assigned 108 adult patients undergoing pancreatectomy to receive one of two 72-h postoperative analgesia protocols: one was TEA, and the other was intravenous patient-controlled analgesia (IV-PCA). The perioperative proportional changes of immunocytes relevant to anticancer immunity-namely natural killer (NK) cells, cytotoxic T cells, helper T cells, mature dendritic cells, and regulatory T (Treg) cells were determined at 1 day before surgery, at the end of surgery and on postoperative day 1,4 and 7 using flow cytometry. In addition, the progression-free survival and overall survival between the two groups were compared.

RESULTS

After surgery, the proportions of NK cells and cytotoxic T cells were significantly decreased; the proportion of B cells and mature dendritic cells and Treg cells were significantly increased. However, the proportions of helper T cells exhibited no significant change. These results were comparable between the two groups. Furthermore, there were no significant differences in progression-free survival (52.75 [39.96] and 57.48 [43.66] months for patients in the TEA and IV-PCA groups, respectively; p = 0.5600) and overall survival (62.71 [35.48] and 75.11 [33.10] months for patients in the TEA and IV-PCA groups, respectively; p = 0.0644).

CONCLUSIONS

TEA was neither associated with favorable anticancer immunity nor favorable oncological outcomes for patients undergoing pancreatectomy.

Decreased survival in patients with pancreatic cancer may be associated with an increase in histopathological expression of inflammasome marker NLRP3

Pancreatic cancer is a malignant neoplasm that, despite its low frequency, has a 5-year survival rate of less than 10%. The study of different histopathological markers has allowed a better understanding of the onset and development of this type of tumor as well as facilitating an approach to clinical variables based on their diagnostic, prognostic, and predictive value. In this sense, the NLRP3 protein of the inflammasome has been shown to be a component of great relevance in the initiation and progression of pancreatic cancer, although the value of this biomarker in patients has not yet been clarified. In this study, we selected 41 patients with pancreatic cancer and followed them for 60 months (5 years), evaluating their NLRP3 expression using immunohistochemical techniques. Furthermore, by performing Kaplan-Meier curves, we evaluated the survival of these patients in relation to their NLRP3 expression. Our results show that a significant percentage of our cohort had high expression of this component (90.74%) and that there is an inverse relationship between the expression of NLRP3 and patient survival. High levels of NLRP3 expression are related to lower survival and worse prognosis in these patients, possibly due to an ineffective immune system response and increased tumor-promoted inflammation. Future studies should be aimed at confirming these results in larger groups and evaluating various clinical strategies based on this knowledge.

Galectin-1 in Pancreatic Ductal Adenocarcinoma: Bridging Tumor Biology, Immune Evasion, and Therapeutic Opportunities

Pancreatic Ductal Adenocarcinoma (PDAC) remains one of the most challenging malignancies to treat, with a complex interplay of molecular pathways contributing to its aggressive nature. Galectin-1 (Gal-1), a member of the galectin family, has emerged as a pivotal player in the PDAC microenvironment, influencing various aspects from tumor growth and angiogenesis to immune modulation. This review provides a comprehensive overview of the multifaceted role of Galectin-1 in PDAC. We delve into its contributions to tumor stroma remodeling, angiogenesis, metabolic reprogramming, and potential implications for therapeutic interventions. The challenges associated with targeting Gal-1 are discussed, given its pleiotropic functions and complexities in different cellular conditions. Additionally, the promising prospects of Gal-1 inhibition, including the utilization of nanotechnology and theranostics, are highlighted. By integrating recent findings and shedding light on the intricacies of Gal-1's involvement in PDAC, this review aims to provide insights that could guide future research and therapeutic strategies.

Association between AHR Expression and Immune Dysregulation in Pancreatic Ductal Adenocarcinoma: Insights from Comprehensive Immune Profiling of Peripheral Blood Mononuclear Cells

Pancreatic cancer, particularly pancreatic ductal adenocarcinoma (PDAC), has an immune suppressive environment that allows tumour cells to evade the immune system. The aryl-hydrocarbon receptor (AHR) is a transcription factor that can be activated by certain exo/endo ligands, including kynurenine (KYN) and other tryptophan metabolites. Once activated, AHR regulates the expression of various genes involved in immune responses and inflammation. Previous studies have shown that AHR activation in PDAC can have both pro-tumorigenic and anti-tumorigenic effects, depending on the context. It can promote tumour growth and immune evasion by suppressing anti-tumour immune responses or induce anti-tumour effects by enhancing immune cell function. In this study involving 30 PDAC patients and 30 healthy individuals, peripheral blood samples were analysed. PDAC patients were categorized into Low (12 patients) and High/Medium (18 patients) AHR groups based on gene expression in peripheral blood mononuclear cells (PBMCs). The Low AHR group showed distinct immune characteristics, including increased levels of immune-suppressive proteins such as PDL1, as well as alterations in lymphocyte and monocyte subtypes. Functional assays demonstrated changes in phagocytosis, nitric oxide production, and the expression of cytokines IL-1, IL-6, and IL-10. These findings indicate that AHR's expression level has a crucial role in immune dysregulation in PDAC and could be a potential target for early diagnostics and personalised therapeutics.

Comparative analysis of the sarcopenia and HALP score on postoperative outcomes in pancreatic cancer patients after pancreatoduodenectomy

BACKGROUND

Sarcopenia and HALP (Hemoglobin, Albumin, Lymphocyte, and Platelet) scores are factors commonly associated with postoperative outcomes used in cancer patients. This study aims to evaluate the effect of these two prognostic factors on postoperative outcomes in operated pancreatic cancer patients and their correlation with each other.

METHODS

The study is a single-center, retrospective study conducted with 179 patients diagnosed with pancreatic adenocarcinoma after pancreatoduodenectomy (PD) between January 2012 and January 2022. The Psoas muscular index (PMI) and HALP scores of the patients were calculated. Cut-off values were determined in order to determine the nutritional status of the patients and to group them. The cut-off value of the HALP score was determined according to survival status. In addition, the clinical data and pathological findings of tumors were collected. These two parameters were evaluated in terms of length of hospital stay, postoperative complication rates, fistula development, and overall survival, and their correlations with each other were examined.

RESULTS

Of the patients, 74 (41.3%) were female, and 105 (58.7%) were male. According to PMI cut-off values, 83 (46.4%) patients were in the sarcopenia group. According to the HALP score cut-off values, 77 (43.1%) patients were in the low HALP group. Sarcopenia and Low HALP group had a higher risk of death (respectively Hazard ratio:5.67, CI:3.58-8.98, Hazard ratio:5.95, CI: 3.72-9.52) (p < 0.001). There was a moderate correlation between PMI and HALP score (rs = 0.34, p = 0.01). The correlation in these values was higher in the female gender.

CONCLUSIONS

In line with the data obtained from our study, HALP score and sarcopenia are among the important parameters used to evaluate postoperative complications and provide information about survival. Patients with a low HALP score and sarcopenic have an increased likelihood of developing postoperative complications and a lower survival.

A Delay in Adjuvant Therapy Is Associated With Worse Prognosis Only in Patients With Transitional Circulating Tumor Cells After Resection of Pancreatic Ductal Adenocarcinoma

OBJECTIVES

The aim of the study was to assess the association of circulating tumor cells (CTCs) with survival as a biomarker in pancreatic ductal adenocarcinoma (PDAC) within the context of a delay in the initiation of adjuvant therapy.

BACKGROUND

Outcomes in patients with PDAC remain poor and are driven by aggressive systemic disease. Although systemic therapies improve survival in resected patients, factors such as a delay in the initiation of adjuvant therapy are associated with worse outcomes. CTCs have previously been shown to be predictive of survival.

METHODS

A retrospective study was performed on PDAC patients enrolled in the prospective CircuLating tUmor cellS in pancreaTic cancER trial (NCT02974764) on CTC-dynamics at the Johns Hopkins Hospital. CTCs were isolated based on size (isolation by size of epithelial tumor cells; Rarecells) and counted and characterized by subtype using immunofluorescence. The preoperative and postoperative blood samples were used to identify 2 CTC types: epithelial CTCs (eCTCs), expressing pancytokeratin, and transitional CTCs (trCTCs), expressing both pancytokeratin and vimentin. Patients who received adjuvant therapy were compared with those who did not. A delay in the receipt of adjuvant therapy was defined as the initiation of therapy ≥8 weeks after surgical resection. Clinicopathologic features, CTCs characteristics, and outcomes were analyzed.

RESULTS

Of 101 patients included in the study, 43 (42.5%) experienced a delay in initiation and 20 (19.8%) did not receive adjuvant therapy. On multivariable analysis, the presence of trCTCs ( P =0.002) and the absence of adjuvant therapy ( P =0.032) were associated with worse recurrence-free survival (RFS). Postoperative trCTC were associated with poorer RFS, both in patients with a delay in initiation (12.4 vs 17.9 mo, P =0.004) or no administration of adjuvant chemotherapy (3.4 vs NR, P =0.016). However, it was not associated with RFS in patients with timely initiation of adjuvant chemotherapy ( P =0.293).

CONCLUSIONS

Postoperative trCTCs positivity is associated with poorer RFS only in patients who either experience a delay in initiation or no receipt of adjuvant therapy. This study suggests that a delay in the initiation of adjuvant therapy could potentially provide residual systemic disease (trCTCs) a window of opportunity to recover from the surgical insult. Future studies are required to validate these findings and explore the underlying mechanisms involved.

Cholecystokinin Receptor Antagonist Induces Pancreatic Stellate Cell Plasticity Rendering the Tumor Microenvironment Less Oncogenic

CCK receptors are expressed on pancreatic cancer epithelial cells, and blockade with receptor antagonists decreases tumor growth. Activated pancreatic stellate cells or myofibroblasts have also been described to express CCK receptors, but the contribution of this novel pathway in fibrosis of the pancreatic cancer microenvironment has not been studied. We examined the effects of the nonselective CCK receptor antagonist proglumide on the activation, proliferation, collagen deposition, differential expression of genes, and migration in both murine and human PSCs. CCK receptor expression was examined using western blot analysis. Collagen production using activated PSCs was analyzed by mass spectroscopy and western blot. Migration of activated PSCs was prevented in vitro by proglumide and the CCK-B receptor antagonist, L365,260, but not by the CCK-A receptor antagonist L365,718. Proglumide effectively decreased the expression of extracellular matrix-associated genes and collagen-associated proteins in both mouse and human PSCs. Components of fibrosis, including hydroxyproline and proline levels, were significantly reduced in PSC treated with proglumide compared to controls. CCK peptide stimulated mouse and human PSC proliferation, and this effect was blocked by proglumide. These investigations demonstrate that targeting the CCK-B receptor signaling pathway with proglumide may alter the plasticity of PSC, rendering them more quiescent and leading to a decrease in fibrosis in the pancreatic cancer microenvironment.

Intratumour microbiome of pancreatic cancer

Pancreatic cancer is a high mortality malignancy with almost equal mortality and morbidity rates. Both normal and tumour tissues of the pancreas were previously considered sterile. In recent years, with the development of technologies for high-throughput sequencing, a variety of studies have revealed that pancreatic cancer tissues contain small amounts of bacteria and fungi. The intratumour microbiome is being revealed as an influential contributor to carcinogenesis. The intratumour microbiome has been identified as a crucial factor for pancreatic cancer progression, diagnosis, and treatment, chemotherapy resistance, and immune response. A better understanding of the biology of the intratumour microbiome of pancreatic cancer contributes to the establishment of better early cancer screening and treatment strategies. This review focuses on the possible origins of the intratumour microbiome in pancreatic cancer, the intratumour localization, the interaction with the tumour microenvironment, and strategies for improving the outcome of pancreatic cancer treatment. Thus, this review offers new perspectives for improving the prognosis of pancreatic cancer.

ENO1 promotes immunosuppression and tumor growth in pancreatic cancer

BACKGROUND

Pancreatic adenocarcinoma (PAAD) is a highly aggressive and malignant cancer type with the highest mortality rate of all major cancers. However, the molecular and tumor immune escape mechanism underlying pancreatic cancer remains largely unclear. α-enolase (ENO1) is a glycolytic enzyme reported to overexpress in a variety of cancer types. This study was undertaken to investigate the functional role and therapeutic potential of ENO1 in pancreatic cancer.

METHODS

We examined the expression levels of ENO1 across a broad spectrum of cancer types from the TCGA database. ENO1-knockout (ENO1-KO) through CRISPR/CAS9 technology in a mouse pancreatic cancer cell line (PAN02) was used to analyze the role of ENO1 on proliferation and colony formation. Flow cytometry and RT-PCR were also applied to analyze T lymphocytes and relevant cytokines.

RESULTS

In the present study, we identified that ENO1 promoted pancreatic cancer cell proliferation. Our bioinformatics data indicated that ENO1 was significantly overexpressed in pancreatic cancer cell lines and tissues. Survival analyses revealed that ENO1 overexpression implicated poor survival of PAAD patients. Knockout of ENO1 expression repressed the ability of proliferation and colony formation in PAN02. In addition, ENO1-KO significantly decreased tumor growth in mouse models. Further flow cytometry and RT-PCR analysis revealed that ENO1-KO modulates the tumor microenvironment (TME), especially in suppressed Treg cells and inducing anti-tumor cytokine responses.

CONCLUSIONS

Taken together, our data showed that ENO1 was an oncogenic biomarker and might serve as a promising target for immunotherapy of pancreatic cancer.

Metabolic Pathways as a Novel Landscape in Pancreatic Ductal Adenocarcinoma

Metabolism plays a fundamental role in both human physiology and pathology, including pancreatic ductal adenocarcinoma (PDAC) and other tumors. Anabolic and catabolic processes do not only have energetic implications but are tightly associated with other cellular activities, such as DNA duplication, redox reactions, and cell homeostasis. PDAC displays a marked metabolic phenotype and the observed reduction in tumor growth induced by calorie restriction with in vivo models supports the crucial role of metabolism in this cancer type. The aggressiveness of PDAC might, therefore, be reduced by interventions on bioenergetic circuits. In this review, we describe the main metabolic mechanisms involved in PDAC growth and the biological features that may favor its onset and progression within an immunometabolic context. We also discuss the need to bridge the gap between basic research and clinical practice in order to offer alternative therapeutic approaches for PDAC patients in the more immediate future.

How can we better predict the prognosis of patients with pancreatic cancer undergoing surgery using an immune-nutritional scoring system?

BACKGROUND

Several immune-nutritional scores have been used to predict the prognosis of pancreatic cancer, but the efficacies of these scores have yet to be compared. This study aimed to compare various immune-nutritional scores and establish a more accurate scoring system to evaluate the prognosis of pancreatic cancer.

METHODS

The preoperative immune-nutritional scores of 411 patients with pancreatic cancer who underwent radical surgery were retrospectively compared. The cut-off point for predicting mortality was determined using X-tile analysis. The efficacies of various immune-nutritional scores for predicting the short- and long-term outcomes of pancreatic cancer were compared. A new nomogram was established based on immune-nutritional scores.

RESULTS

Regardless of the immune-nutritional scoring method, the short- and long-term outcomes of the group with better nutritional status were better than those of the other groups. The modified Glasgow prognosis score (C-index = 0.74) and controlling nutritional status score (C-index = 0.61) were more effective for predicting the prognosis of pancreatic cancer. A nomogram based on controlling nutritional status, red blood cell distribution, modified Glasgow prognosis score, and tumor node metastasis classification stage was more accurate than any single immune-nutritional score for predicting pancreatic cancer prognosis (C-index = 0.78).

CONCLUSION

Patients with pancreatic cancer with poor preoperative nutritional status have a poorer prognosis. We identify a new nomogram based on immune-nutritional scores that provides an accurate and individualized prediction of prognosis for pancreatic cancer.

Discoveries in Pancreatic Physiology and Disease Biology Using Single-Cell RNA Sequencing

Transcriptome analysis is used to study gene expression in human tissues. It can promote the discovery of new therapeutic targets for related diseases by characterizing the endocrine function of pancreatic physiology and pathology, as well as the gene expression of pancreatic tumors. Compared to whole-tissue RNA sequencing, single-cell RNA sequencing (scRNA-seq) can detect transcriptional activity within a single cell. The scRNA-seq had an invaluable contribution to discovering previously unknown cell subtypes in normal and diseased pancreases, studying the functional role of rare islet cells, and studying various types of cells in diabetes as well as cancer. Here, we review the recent in vitro and in vivo advances in understanding the pancreatic physiology and pathology associated with single-cell sequencing technology, which may provide new insights into treatment strategy optimization for diabetes and pancreatic cancer.

Interrupting the nitrosative stress fuels tumor-specific cytotoxic T lymphocytes in pancreatic cancer

Background

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest tumors owing to its robust desmoplasia, low immunogenicity, and recruitment of cancer-conditioned, immunoregulatory myeloid cells. These features strongly limit the success of immunotherapy as a single agent, thereby suggesting the need for the development of a multitargeted approach. The goal is to foster T lymphocyte infiltration within the tumor landscape and neutralize cancer-triggered immune suppression, to enhance the therapeutic effectiveness of immune-based treatments, such as anticancer adoptive cell therapy (ACT).

Methods

We examined the contribution of immunosuppressive myeloid cells expressing arginase 1 and nitric oxide synthase 2 in building up a reactive nitrogen species (RNS)-dependent chemical barrier and shaping the PDAC immune landscape. We examined the impact of pharmacological RNS interference on overcoming the recruitment and immunosuppressive activity of tumor-expanded myeloid cells, which render pancreatic cancers resistant to immunotherapy.

Results

PDAC progression is marked by a stepwise infiltration of myeloid cells, which enforces a highly immunosuppressive microenvironment through the uncontrolled metabolism of L-arginine by arginase 1 and inducible nitric oxide synthase activity, resulting in the production of large amounts of reactive oxygen and nitrogen species. The extensive accumulation of myeloid suppressing cells and nitrated tyrosines (nitrotyrosine, N-Ty) establishes an RNS-dependent chemical barrier that impairs tumor infiltration by T lymphocytes and restricts the efficacy of adoptive immunotherapy. A pharmacological treatment with AT38 ([3-(aminocarbonyl)furoxan-4-yl]methyl salicylate) reprograms the tumor microenvironment from protumoral to antitumoral, which supports T lymphocyte entrance within the tumor core and aids the efficacy of ACT with telomerase-specific cytotoxic T lymphocytes.

Conclusions

Tumor microenvironment reprogramming by ablating aberrant RNS production bypasses the current limits of immunotherapy in PDAC by overcoming immune resistance.

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.

Towards an updated view on the clinical management of pancreatic adenocarcinoma: Current and future perspectives

Pancreatic cancer has a dire prognosis and will represent the second leading cause of cancer death in the next 10 years. The multifactorial approach represents one of the main issues in controlling the extension of this neoplasm. In recent years, the characteristics of the tumor microenvironment, metastasis mechanisms and the relationship between immune system and neoplastic cells have been described, which has made it possible to understand the pathophysiology of pancreatic adenocarcinoma. Currently, there is a failure to provide an effective preventive method or early detection, so patients present with an advanced stage at the time of diagnosis. Despite numerous efforts, little progress has been made in clinical outcome and in improving survival in long term. Therefore, in the recent years, diverse diagnostic tests, treatments and possible approaches have been developed in the fields of radiotherapy, chemotherapy and surgery to find a combination of them that improves life expectancy in patients diagnosed with pancreatic cancer. At the moment, numerous clinical trials are being conducted to evaluate preventive diagnostic procedures such as serological markers or perfecting available imaging tests. On the other hand, implementation of immunotherapy is being studied in a neoplasm that has lagged in the application of this procedure since present possible treatments do not substantially improve quality of life. Therefore, the purpose of our study is to summarize the main progresses that have been made in the diagnosis, treatment and screening of this disease, explaining the limitations that have been observed and analyzing future prospects in the management of this illness.

Improved Immunotherapy Efficacy by Vascular Modulation

Several strategies have been developed to modulate the tumour vasculature for cancer therapy including anti-angiogenesis and vascular normalisation. Vasculature modulation results in changes to the tumour microenvironment including oxygenation and immune cell infiltration, therefore lending itself to combination with cancer therapy. The development of immunotherapies has led to significant improvements in cancer treatment. Particularly promising are immune checkpoint blockade and CAR T cell therapies, which use antibodies against negative regulators of T cell activation and T cells reprogrammed to better target tumour antigens, respectively. However, while immunotherapy is successful in some patients, including those with advanced or metastatic cancers, only a subset of patients respond. Therefore, better predictors of patient response and methods to overcome resistance warrant investigation. Poor, or periphery-limited, T cell infiltration in the tumour is associated with poor responses to immunotherapy. Given that (1) lymphocyte recruitment requires leucocyte-endothelial cell adhesion and (2) the vasculature controls tumour oxygenation and plays a pivotal role in T cell infiltration and activation, vessel targeting strategies including anti-angiogenesis and vascular normalisation in combination with immunotherapy are providing possible new strategies to enhance therapy. Here, we review the progress of vessel modulation in enhancing immunotherapy efficacy.

Identification of tumor antigens and immune subtypes in lower grade gliomas for mRNA vaccine development

BACKGROUND

As an important part of tumor immunotherapy for adjunct, therapeutic tumor vaccines have been effective against multiple solid cancers, while their efficacy against lower grade glioma (LGG) remains undefined. Immunophenotyping of tumors is an essential tool to evaluate the immune function of patients with immunodeficiency or autoimmunity. Therefore, this study aims to find the potential tumor antigen of LGG and identify the suitable population for cancer vaccination based on the immune landscape.

METHOD

The genomic and clinical data of 529 patients with LGG were obtained from TCGA, the mRNA_seq data of normal brain tissue were downloaded from GTEx. Differential expression gene and mutation analysis were performed to screen out potential antigens, K-M curves were carried out to investigate the correlation between the level of potential antigens and OS and DFS of patients. TIMER dataset was used to explore the correlation between genes and immune infiltrating cells. Immunophenotyping of 529 tumor samples was based on the single-sample gene sets enrichment analysis. Cibersort and Estimate algorithm were used to explore the tumor immune microenvironment characteristics in each immune subtype. Weighted gene co-expression network analysis (WGCNA) clustered immune-related genes and screened the hub genes, and pathway enrichment analyses were performed on the hub modules related to immune subtype in the WGCNA.

RESULTS

Selecting for the mutated, up-regulated, prognosis- and immune-related genes, four potential tumor antigens were identified in LGG. They were also significantly positively associated with the antigen-presenting immune cells (APCs). Three robust immune subtypes, IS1, IS2 and IS3, represented immune status "desert", "immune inhibition", and "inflamed" respectively, which might serve as a predictive parameter. Subsequently, clinicopathological features, including the codeletion status of 1p19q, IDH mutation status, tumor mutation burden, tumor stemness, etc., were significantly different among subtypes.

CONCLUSION

FCGBP, FLNC, TLR7, and CSF2RA were potential antigens for developing cancer vaccination, and the patients in IS3 were considered the most suitable for vaccination in LGG.

Overcoming the Tumor Microenvironmental Barriers of Pancreatic Ductal Adenocarcinomas for Achieving Better Treatment Outcomes

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with the lowest survival rate among all solid tumors. The lethality of PDAC arises from late detection and propensity of the tumor to metastasize and develop resistance against chemo and radiation therapy. A highly complex tumor microenvironment composed of dense stroma, immune cells, fibroblast, and disorganized blood vessels, is the main obstacle to current PDAC therapy. Despite the tremendous success of immune checkpoint inhibitors (ICIs) in cancers, PDAC remains one of the poorest responders of ICIs therapy. The immunologically "cold" phenotype of PDAC is attributed to the low mutational burden, high infiltration of myeloid-derived suppressor cells and T-regs, contributing to a significant immunotherapy resistance mechanism. Thus, the development of innovative strategies for turning immunologically "cold" tumor into "hot" ones is an unmet need to improve the outcome of PDAC ICIs therapies. Other smart strategies, such as nanomedicines, sonic Hedgehog inhibitor, or smoothened inhibitor, are discussed to enhance chemotherapeutic agents' efficiency by disrupting the PDAC stroma. This review highlights the current challenges and various preclinical and clinical strategies to overcome current PDAC therapy difficulties, thus significantly advancing PDAC research knowledge.

Immunotherapy for pancreatic cancer

Pancreatic cancer, a highly lethal cancer, has the lowest 5-year survival rate for several reasons, including its tendency for the late diagnosis, a lack of serologic markers for screening, aggressive local invasion, its early metastatic dissemination, and its resistance to chemotherapy/radiotherapy. Pancreatic cancer evades immunologic elimination by a variety of mechanisms, including induction of an immunosuppressive microenvironment. Cancer-associated fibroblasts interact with inhibitory immune cells, such as tumor-associated macrophages and regulatory T cells, to form an inflammatory shell-like desmoplastic stroma around tumor cells. Immunotherapy has the potential to mobilize the immune system to eliminate cancer cells. Nevertheless, although immunotherapy has shown brilliant results across a wide range of malignancies, only anti-programmed cell death 1 antibodies have been approved for use in patients with pancreatic cancer who test positive for microsatellite instability or mismatch repair deficiency. Some patients treated with immunotherapy who show progression based on conventional response criteria may prove to have a durable response later. Continuation of immune-based treatment beyond disease progression can be chosen if the patient is clinically stable. Immunotherapeutic approaches for pancreatic cancer treatment deserve further exploration, given the plethora of combination trials with other immunotherapeutic agents, targeted therapy, stroma-modulating agents, chemotherapy, and multi-way combination therapies.

Role of different immune cells and metabolic pathways in modulating the immune response in pancreatic cancer (Review)

Pancreatic cancer is an aggressive cancer, making it a leading cause of cancer‑related deaths. It is characteristically resistant to treatment, which results in low survival rates. In pancreatic cancer, immune cells undergo transitions that can inhibit or promote their functions, enabling treatment resistance and tumor progression. These transitions can be fostered by metabolic pathways that are dysregulated during tumorigenesis. The present review aimed to summarize the different immune cells and their roles in pancreatic cancer. The review also highlighted the individual metabolic pathways in pancreatic cancer and how they enable transitions in immune cells. Finally, the potential of targeting metabolic pathways for effective therapeutic strategies was considered.

Multidisciplinary standards of care and recent progress in pancreatic ductal adenocarcinoma

Despite tremendous gains in the molecular understanding of exocrine pancreatic cancer, the prognosis for this disease remains very poor, largely because of delayed disease detection and limited effectiveness of systemic therapies. Both incidence rates and mortality rates for pancreatic cancer have increased during the past decade, in contrast to most other solid tumor types. Recent improvements in multimodality care have substantially improved overall survival, local control, and metastasis-free survival for patients who have localized tumors that are amenable to surgical resection. The widening gap in prognosis between patients with resectable and unresectable or metastatic disease reinforces the importance of detecting pancreatic cancer sooner to improve outcomes. Furthermore, the developing use of therapies that target tumor-specific molecular vulnerabilities may offer improved disease control for patients with advanced disease. Finally, the substantial morbidity associated with pancreatic cancer, including wasting, fatigue, and pain, remains an under-addressed component of this disease, which powerfully affects quality of life and limits tolerance to aggressive therapies. In this article, the authors review the current multidisciplinary standards of care in pancreatic cancer with a focus on emerging concepts in pancreatic cancer detection, precision therapy, and survivorship.

BxPC-3-Derived Small Extracellular Vesicles Induce FOXP3+ Treg through ATM-AMPK-Sirtuins-Mediated FOXOs Nuclear Translocations

Immunotherapy in pancreatic ductal adenocarcinoma (PDAC) treatment faces serious challenges, due particularly to the poor immunogenicity. Cancer cell-derived small extracellular vesicles (sEVs) play important roles in damaging the immune system. However, the effects of pancreatic cancer-derived sEVs on T lymphocytes are unknown. Here we investigated changes in phenotypes and signal transduction pathways in sEVs-treated T lymphocytes. We identified the overexpression of immune checkpoint proteins PD-1, PD-L1, CTLA4, and Tim-3 and the enrichment of FOXP3+ Treg cluster in sEVs-treated T lymphocytes by CyTOF. Gene set enrichment analysis revealed that DNA damage response and metabolic pathways might be involved in sEVs-induced Tregs. ATM, AMPK, SIRT1, SIRT2, and SIRT6 were activated sequentially in sEVs-treated T lymphocytes and essential for sEVs-upregulated expressions of FOXO1A, FOXO3A, and FOXP3. Our study reveals the impact and mechanism of pancreatic cancer cell-derived sEVs on T lymphocytes and may provide insights into developing immunotherapy strategies for PDAC treatment.

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Human pancreatic cancer cells-derived sEVs induce Treg promotion

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DNA damage responses and metabolism are altered in sEVs-stimulated T lymphocytes

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ATM-AMPK-SIRT1/2/6-FOXO1A/3A axis plays a role in sEVs-induced Treg

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FOXO1A, FOXO3A, and FOXP3 are highly expressed in pancreatic cancer-involved lymph nodes

Tumor microenvironment in chemoresistance, metastasis and immunotherapy of pancreatic cancer

Pancreatic cancer (PC) is a fatal disease with high malignancy and difficult for early diagnosis. PC causes more than 400,000 patient deaths world widely and becomes the severe health problems. The tumor microenvironment (TME) is comprised of acellular stroma, pancreatic stellate cells, immune cells, and soluble factors. TME is maintained by continuous cell-matrix and cell-cell interactions. TME induced by the interaction among pancreatic cancer cells, epithelial cells and stromal cells is essential for the progression of PC and leads to resistance to chemotherapy. Components in the microenvironment can also promote the formation of connective tissue in the primary or metastatic site, or promote the metastatic ability of PC by enhancing angiogenesis, epithelial-mesenchymal transformation, and lymph angiogenesis. In addition, the TME also leaves pancreatic cancer unsusceptible to different immunotherapeutic strategies. In this review, we summarized the current knowledge about TME in PC. And the focus was placed on the role of TME in chemotherapeutic resistance and metastasis in the field of PC. And we also paid attention to the immunological therapy targeting the TME, aiming to provide the novel therapy for pancreatic cancer.

Metabolomics profile in gastrointestinal cancers: Update and future perspectives

Despite recent progress in diagnosis and therapy, gastrointestinal (GI) cancers remain one of the most important causes of death with a poor prognosis due to late diagnosis. Serum tumor markers and detection of occult blood in the stool are the current tests used in the clinic of GI cancers; however, these tests are not useful as diagnostic screening since they have low specificity and low sensitivity. Considering that one of the hallmarks of cancer is dysregulated metabolism and metabolomics is an optimal approach to illustrate the metabolic mechanisms that belong to living systems, is now clear that this -omics could open a new way to study cancer. In the last years, nuclear magnetic resonance (NMR) metabolomics has demonstrated to be an optimal approach for diseases' diagnosis nevertheless a few studies focus on the NMR capability to find new biomarkers for early diagnosis of GI cancers. For these reasons in this review, we will give an update on the status of NMR metabolomic studies for the diagnosis and development of GI cancers using biological fluids.

H2Mab-19 Anti-Human Epidermal Growth Factor Receptor 2 Monoclonal Antibody Therapy Exerts Antitumor Activity in Pancreatic Cancer Xenograft Models

Overexpression of human epidermal growth factor receptor 2 (HER2) has been reported in breast cancer, gastric, lung, colorectal, oral, and pancreatic cancers. HER2 expression is associated with poor clinical outcomes. An anti-HER2 humanized antibody, trastuzumab, has improved survival rates in patients with HER2-overexpressing breast and gastric cancers. Previously, we established a novel anti-HER2 monoclonal antibody (mAb), H₂Mab-19 (IgG_2b, kappa). It has also been characterized for breast, oral, and colon cancers. In this study, we investigated the antitumor activities of H₂Mab-19 in pancreatic cancer xenograft models. We selected MIA PaCa-2, a pancreatic cancer cell line which expresses HER2. H₂Mab-19 showed high binding affinity (K_D: 1.2 × 10^-8 M) against MIA PaCa-2 cells. Furthermore, H₂Mab-19 significantly reduced tumor development in a MIA PaCa-2 xenograft model. These results suggest that treatment with H₂Mab-19 may be a useful therapy for patients with HER2-expressing pancreatic cancers.

The present and future of systemic and microenvironment-targeted therapy for pancreatic adenocarcinoma

Metastatic pancreatic adenocarcinoma remains one of the deadliest cancer diagnoses with 5-year survival rates as low as 3%. For decades, gemcitabine remained the mainstay of systemic therapy before the approvals of FOLFIRINOX and gemcitabine with nab-paclitaxel. Despite these advances in the early 2010s, almost all patients progress on systemic chemotherapy and significant effort is needed to identify novel therapeutic targets. A promising array of approaches is currently under investigation, enabled by deeper understanding of the immune system within the tumor microenvironment (TME) and of the key vulnerabilities in pathways essential for tumor survival. In this review, we will explore the different approaches to boost tumor immunity and to target tumor metabolic pathways that are currently under clinical investigation for systemic treatment, and highlight the promising therapeutic areas that may give rise to the next generation of therapies for pancreatic cancer.

Oncologic impact of preoperative prognostic nutritional index change in resected pancreatic cancer following neoadjuvant chemotherapy

BACKGROUND

Although several studies have focused on the oncologic impact of the preoperative prognostic nutritional index (PNI), there is no study correlating the preoperative PNI changes with the oncologic outcome of resected pancreatic cancer following neoadjuvant chemotherapy (NAC).

METHODS

We retrospectively analyzed 107 pancreatic ductal adenocarcinoma patients who underwent NAC followed by surgical resection. ΔPNI was defined as post-NAC PNI subtracted from pre-NAC PNI. Patients were divided into high (≥-1.94, n = 54) and low ΔPNI groups (<-1.94, n = 53). Long-term oncologic outcomes, such as overall survival (OS) and disease-free survival (DFS), were compared. Univariate and multivariate analysis were used to identify independent prognostic factors.

RESULTS

The high ΔPNI group correlated with lower pre-NAC PNI (46.96 ± 4.68 vs. 51.77 ± 5.63, p < 0.001) and higher post-NAC PNI (50.05 ± 4.80 vs. 42.56 ± 7.44, p < 0.001) more than the low ΔPNI group. The high ΔPNI group was also associated with longer OS compared with the low ΔPNI group (mean OS: 63.97 months [95% CI: 49.95-77.99] vs. 41.16 months [95% CI: 27.66-54.66], p = 0.003); there was no significant difference in DFS (p > 0.05). Multivariate analysis revealed that low ΔPNI was an independent risk factor for OS (HR, 3.516; 95% CI, 1.885-6.558; p < 0.001), but not for DFS (p > 0.05).

CONCLUSIONS

Low ΔPNI (<-1.94) was an independent risk factor for the overall survival of resected pancreatic cancer patients following NAC. In the preoperative setting, improving the PNI can better the long-term oncologic outcome of this condition.

Deciphering the Crosstalk Between Myeloid-Derived Suppressor Cells and Regulatory T Cells in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a fatal disease with rising incidence and a remarkable resistance to current therapies. The reasons for this therapeutic failure include the tumor's extensive infiltration by immunosuppressive cells such as myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs). By using light sheet fluorescent microscopy, we identified here direct interactions between these major immunoregulatory cells in PDAC. The in vivo depletion of MDSCs led to a significant reduction in Tregs in the pancreatic tumors. Through videomicroscopy and ex vivo functional assays we have shown that (i) MDSCs are able to induce Treg cells in a cell-cell dependent manner; (ii) Treg cells affect the survival and/or the proliferation of MDSCs. Furthermore, we have observed contacts between MDSCs and Treg cells at different stages of human cancer. Overall our findings suggest that interactions between MDSCs and Treg cells contribute to PDAC immunosuppressive environment.

A novel gemcitabine derivative-loaded liposome with great pancreas-targeting ability

Gemcitabine (Gem) is a standard first-line treatment for pancreatic cancer (PC). However, its chemotherapeutic efficacy is hampered by various limitations such as short half-life, metabolic inactivation, and lack of tumor localizing. We previously synthesized a lipophilic Gem derivative (Gem formyl hexadecyl ester, GemC16) that exhibited improved antitumor activity in vitro. In this study, a target ligand N,N-dimethyl-1,3-propanediamine was conjugated to 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[hydroxyl succinimidyl (polyethylene glycol-2000)] (DSPE-PEG-NHS) to form DSPE-PEG-2N. Then, pancreas-targeting liposomes (2N-LPs) were prepared using the film dispersion-ultrasonic method. GemC16-loaded 2N-LPs displayed near-spherical shapes with an average size distribution of 157.2 nm (polydispersity index (PDI) = 0.201). The encapsulation efficiency of GemC16 was up to 97.3% with a loading capacity of 8.9%. In human PC cell line (BxPC-3) and rat pancreatic acinar cell line (AR42J), cellular uptake of 2N-LPs was significantly enhanced compared with that of unmodified PEG-LPs. 2N-LPs exhibited more potent in vitro cytotoxicity against BxPC-3 and AR42J cell lines than PEG-LPs. After systemic administration in mice, 2N-LPs remarkably increased drug distribution in the pancreas. In an orthotopic tumor mouse model of PC, GemC16-bearing liposomes were more effective in preventing tumor growth than free GemC16. Among these treatments, 2N-LPs showed the best curative effect. Together, 2N-LPs represent a promising nanocarrier to achieve pancreas-targeting drug delivery, and this work would provide new ideas for the chemotherapy of PC.

The Role of Mesothelin as a Diagnostic and Therapeutic Target in Pancreatic Ductal Adenocarcinoma: A Comprehensive Review

Mesothelin is a tumor differentiation antigen, which is highly expressed in several solid neoplasms, including pancreatic cancer. Its selective expression on malignant cells and on only a limited number of healthy tissues has made it an interesting candidate for investigation as a diagnostic and prognostic biomarker and as a therapeutic target. Based on a strong preclinical rationale, a number of therapeutic agents targeting mesothelin have entered clinical trials, including immunotoxins, monoclonal antibodies, antibody-drug conjugates, cancer vaccines, and adoptive T cell therapies with chimeric antigen receptors. In pancreatic cancer, mesothelin has been investigated mainly to address two unmet issues: the urgent need for new laboratory techniques for early tumor detection and the lack of successfully targetable oncogenic alterations for patients' treatment. In this review, we describe the clinicopathological significance of mesothelin expression in pancreatic cancer initiation and progression, we summarize available studies evaluating mesothelin as a potential diagnostic and prognostic biomarker in this disease, and we discuss current evidence and future perspectives of preclinical and clinical studies testing mesothelin as a molecular target for pancreatic cancer treatment.

A Phase Ib Study of the Combination of Personalized Autologous Dendritic Cell Vaccine, Aspirin, and Standard of Care Adjuvant Chemotherapy Followed by Nivolumab for Resected Pancreatic Adenocarcinoma-A Proof of Antigen Discovery Feasibility in Three Patients

Despite the promising therapeutic effects of immune checkpoint blockade (ICB), most patients with solid tumors treated with anti-PD-1/PD-L1 monotherapy do not achieve objective responses, with most tumor regressions being partial rather than complete. It is hypothesized that the absence of pre-existing antitumor immunity and/or the presence of additional tumor immune suppressive factors at the tumor microenvironment are responsible for such therapeutic failures. It is therefore clear that in order to fully exploit the potential of PD-1 blockade therapy, antitumor immune response should be amplified, while tumor immune suppression should be further attenuated. Cancer vaccines may prime patients for treatments with ICB by inducing effective anti-tumor immunity, especially in patients lacking tumor-infiltrating T-cells. These "non-inflamed" non-permissive tumors that are resistant to ICB could be rendered sensitive and transformed into "inflamed" tumor by vaccination. In this article we describe a clinical study where we use pancreatic cancer as a model, and we hypothesize that effective vaccination in pancreatic cancer patients, along with interventions that can reprogram important immunosuppressive factors in the tumor microenvironment, can enhance tumor immune recognition, thus enhancing response to PD-1/PD-L1 blockade. We incorporate into the schedule of standard of care (SOC) chemotherapy adjuvant setting a vaccine platform comprised of autologous dendritic cells loaded with personalized neoantigen peptides (PEP-DC) identified through our own proteo-genomics antigen discovery pipeline. Furthermore, we add nivolumab, an antibody against PD-1, to boost and maintain the vaccine's effect. We also demonstrate the feasibility of identifying personalized neoantigens in three pancreatic ductal adenocarcinoma (PDAC) patients, and we describe their optimal incorporation into long peptides for manufacturing into vaccine products. We finally discuss the advantages as well as the scientific and logistic challenges of such an exploratory vaccine clinical trial, and we highlight its novelty.

Gene Expression Comparison between the Lymph Node-Positive and -Negative Reveals a Peculiar Immune Microenvironment Signature and a Theranostic Role for WNT Targeting in Pancreatic Ductal Adenocarcinoma: A Pilot Study

Over the past several years there has been much debate with regards to the prognostic and clinical significance of pancreatic ductal adenocarcinoma (PDAC) with lymph nodes metastasis. The PDAC gene expression knowledge and the biologic alterations underlying the lymph node involvement convey a clinical implication in dealing with the theranostic window. To this end, we provide an original bioinformatic dissection of the gene expression differences of PDAC according to the nodal involvement from a large public available dataset. Comprehensive transcriptomic analysis from 143 RNA-seq patient's derived samples indicated that WNT increased activation and a peculiar immune microenvironment identify subjects with nodal involvement. In frame of this thinking, we validated the WNT pathway role in increasing the likelihood of lymphatic dissemination in vitro. Moreover, we demonstrated for the first time in a PDAC model the potential therapeutic window that XAV-939-a specific WNT pathway inhibitor-has in re-educating a tumor-permissive immune system. Finally, we outline the potential implication on bystander molecular drivers exerted by WNT molecular inhibition, providing a picture of the proteomic oncogenic landscape changes elicited by XAV-939 on PDAC cells and their clinical implication. Our findings hold the promise to identify novel immune-based therapeutic strategies targeting WNT to enhance PDAC cytotoxicity and restore anti-PDAC immunity in node-positive disease.

Pancreatic Cancer and Immunotherapy: Resistance Mechanisms and Proposed Solutions

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) continues to be one of the most aggressive and lethal diseases in the world. The success of immunotherapy in other types of malignancy has led to further trials to understand better the role of immunotherapy in PDAC. However, initial studies with immunotherapy, namely, the checkpoint inhibitors, in PDAC have not been met with the same outcomes. The purpose of this review is to identify and discuss the various resistance mechanisms of PDAC to immunotherapy (pancreatic stroma, genetic predisposition/epigenetics, and the immune inhibitory cells, cytokines, soluble factors, and enzymes that comprise the tumor microenvironment) and the solutions currently being studied to overcome them.

CONCLUSIONS

Various preclinical and early clinical studies have shown that immunotherapy, especially checkpoint inhibitors, in PDAC may be efficacious as part of a multi-modal treatment, in combination with other therapies that target these resistance mechanisms. Several clinical trials are ongoing to explore this concept further.

Stromal Microenvironment Shapes the Intratumoral Architecture of Pancreatic Cancer

Single-cell technologies have described heterogeneity across tissues, but the spatial distribution and forces that drive single-cell phenotypes have not been well defined. Combining single-cell RNA and protein analytics in studying the role of stromal cancer-associated fibroblasts (CAFs) in modulating heterogeneity in pancreatic cancer (pancreatic ductal adenocarcinoma [PDAC]) model systems, we have identified significant single-cell population shifts toward invasive epithelial-to-mesenchymal transition (EMT) and proliferative (PRO) phenotypes linked with mitogen-activated protein kinase (MAPK) and signal transducer and activator of transcription 3 (STAT3) signaling. Using high-content digital imaging of RNA in situ hybridization in 195 PDAC tumors, we quantified these EMT and PRO subpopulations in 319,626 individual cancer cells that can be classified within the context of distinct tumor gland "units." Tumor gland typing provided an additional layer of intratumoral heterogeneity that was associated with differences in stromal abundance and clinical outcomes. This demonstrates the impact of the stroma in shaping tumor architecture by altering inherent patterns of tumor glands in human PDAC.

Combining the Specific Anti-MUC1 Antibody TAB004 and Lip-MSA-IL-2 Limits Pancreatic Cancer Progression in Immune Competent Murine Models of Pancreatic Ductal Adenocarcinoma

Immunotherapy regimens have shown success in subsets of cancer patients; however, their efficacy against pancreatic ductal adenocarcinoma (PDA) remain unclear. Previously, we demonstrated the potential of TAB004, a monoclonal antibody targeting the unique tumor-associated form of MUC1 (tMUC1) in the early detection of PDA. In this study, we evaluated the therapeutic benefit of combining the TAB004 antibody with Liposomal-MSA-IL-2 in immune competent and human MUC1 transgenic (MUC1.Tg) mouse models of PDA and investigated the associated immune responses. Treatment with TAB004 + Lip-MSA-IL-2 resulted in significantly improved survival and slower tumor growth compared to controls in MUC1.Tg mice bearing an orthotopic PDA.MUC1 tumor. Similarly, in the spontaneous model of PDA that expresses human MUC1, the combination treatment stalled the progression of pancreatic intraepithelial pre-neoplastic (PanIN) lesion to adenocarcinoma. Treatment with the combination elicited a robust systemic and tumor-specific immune response with (a) increased percentages of systemic and tumor infiltrated CD45+CD11b+ cells, (b) increased levels of myeloperoxidase (MPO), (c) increased antibody-dependent cellular cytotoxicity/phagocytosis (ADCC/ADCP), (d) decreased percentage of immune regulatory cells (CD8+CD69+ cells), and (e) reduced circulating levels of immunosuppressive tMUC1. We report that treatment with a novel antibody against tMUC1 in combination with a unique formulation of IL-2 can improve survival and lead to stable disease in appropriate models of PDA by reducing tumor-induced immune regulation and promoting recruitment of CD45+CD11b+ cells, thereby enhancing ADCC/ADCP.

IL-39 acts as a friend to pancreatic cancer

Pancreatic cancer is the most lethal digestive cancer and the fourth leading cause of cancer death in the US. IL-39, a heterodimer of p19 and EBI3, is a newly found cytokine and its role in the pathogenesis of neoplasia has not been studied yet. This study was designed to investigate the direct role of IL-39 in the growth of pancreatic cancer. Clonogenic survival assay, cell proliferation, and caspase-3 activity kits were used to evaluate the direct effects of IL-39 on cell survival, proliferation and apoptosis of the widely studied pancreatic cancer cell line MiaPaCa-2. We further investigated the possible molecular mechanisms by using RT-PCR and IHC. The percentage of colonies of pancreatic cancer cells increased significantly in the presence of IL-39. This was paralleled with the increase in the OD value of cancer cells in the presence of IL-39. Interestingly, the relative caspase-3 activity in cancer cells decreased significantly in the presence of IL-39. Furthermore, the pro-tumor effect of IL-39 on pancreatic cancer cells correlated with decreased anti-proliferative molecule p21.The anti-apoptotic effect of IL-39 correlated with decreased pro-apoptotic molecule TRAILR1. These results suggest that IL-39 favors growth of pancreatic cancer by promoting growth and inhibiting apoptosis of cancer cells. This suggests that IL-39 acts as a friend to pancreatic cancer. Thus, inhibition of effect of IL-39 on cells might be a promising strategy to treat pancreatic cancer.

Local Blockade of Interleukin 10 and C-X-C Motif Chemokine Ligand 12 with Nano-Delivery Promotes Antitumor Response in Murine Cancers

In many cancers, the tumor microenvironment (TME) is largely immune suppressive, blocking the antitumor immunity and resulting in immunotherapy resistance. Interleukin 10 (IL-10) is a major player controlling the immunosuppressive TME in different murine tumor models. Increased IL-10 production suppresses intratumoral dendritic cell production of interleukin 12, thereby limiting antitumor cytotoxic T-cell responses and activation of NK cells during therapy. We engineered, formulated, and delivered genes encoding an IL-10 protein trap to change immunosuppressive TME, which could enhance antitumor immunity. Additionally, to achieve stronger and long-term therapeutic efficacy in a pancreatic cancer model, we targeted C-X-C motif chemokine ligand 12 (CXCL12), a key factor for inhibiting T-cell tumor infiltration, and simultaneously delivered an IL-10 trap. Following three injections of the lipid-protamine-DNA (LPD) nanoparticles loaded with trap genes (IL-10 trap and CXCL12 trap), we found tumor growth reduction and significantly prolonged survival of the host compared to control groups. Furthermore, the combination trap gene treatment significantly reduced immunosuppressive cells, such as M2 macrophages, MDSCs, and PD-L1⁺ cells, and activated immunosuppressive tolerogenic dendritic cells, NK cells, and macrophages intratumorally. We have also shown that, when effectively delivered to the tumor, the IL-10 trap gene alone can inhibit triple-negative breast cancer growth. This strategy may allow clinicians and researchers to change the immunosuppressive microenvironment in the tumor with either a single therapeutic agent or in combination with other immunotherapies to prime the immune system, preventing cancer invasion and prolonging patient survival.

Long-term survival of pancreatic cancer patients treated with multimodal therapy combined with WT1-targeted dendritic cell vaccines

BACKGROUND/AIM

Pancreatic ductal adenocarcinoma (PDA) remains one of the most aggressive tumors with a dismally poor prognosis. Although surgical resection remains the only potentially curative treatment, most PDAs are not surgically resectable at diagnosis. Therefore, multimodal therapy is urgently needed to improve the long-term survival of PDA patients.

METHODS

Six eligible PDA patients underwent multimodal therapy comprising dendritic cells (DCs) pulsed with Wilms' tumor 1 (WT1) peptide (DC/WT1-I) restricted by the human leukocyte antigen (HLA) class I (A*24:02 or A*02:06) allele, chemotherapy, radiation, and/or surgery. Patient laboratory data, DC/WT1-I-specific delayed-type hypersensitivity (DTH) reactions, and WT1-specific immune responses were analyzed to assess the prognostic markers of multimodal therapy.

RESULTS

Compared to 2-treatment type combinations, multimodal therapy involving 3 to 4 treatment types was significantly associated with longer overall survival (p = 0.0177). Moreover, after 7 DC/WT1-I vaccinations, the progression-free survival (PFS) of PDA patients with a neutrophil to lymphocyte ratio (NLR) or C-reactive protein (CRP) level less than the median was superior to that of PDA patients with values above the median (p = 0.0246). PDA patients with an overall survival (OS)>1000 days had significantly more lymphocytes after one DC/WT1-I vaccination course than did those with an OS<1000 days.

CONCLUSION

Multimodal therapy involving the DC/WT1-I vaccination may benefit patients with advanced PDA. However, comparing the limited number of PDA patients in terms of survival is difficult because the patients were at different disease stages and received different treatments. Further studies are needed to evaluate the clinical benefits of this multimodal therapy.

Immunotherapy for pancreatic cancer: A long and hopeful journey

Multiple therapeutic strategies have been developed to treat pancreatic cancer. However, the outcomes of these approaches are disappointing. Due to deeper understandings of the pivotal roles of the immune system in pancreatic cancer tumorigenesis and progression, novel therapeutic strategies based on immune cells and the tumor microenvironment are being investigated. Some of these approaches, such as checkpoint inhibitors, chimeric antigen receptor T-cell therapy, and BiTE antibodies, have achieved exciting outcomes in preclinical and clinical trials. The current review describes the roles of immune cells and the immunosuppressive microenvironment in the development of pancreatic cancer, as well as the preclinical and clinical outcomes and benefits of recent immunotherapeutic approaches, which may help us further disclose the mechanisms of pancreatic cancer progression and the dialectical views of feasibility and effectiveness of immunotherapy in treatment of pancreatic cancer.

Prognostic value of PDL1 expression in pancreatic cancer

Pancreatic cancer is one of the most aggressive human cancers. PD1/PDL1-inhibitors recently showed promising results in different cancers with correlation between PDL1 tumor expression and responses. Expression of programmed cell death receptor ligand 1 (PDL1) has been scarcely studied in pancreatic cancer. In this retrospective study, we analyzed PDL1 mRNA expression in 453 clinical pancreatic cancer samples profiled using DNA microarrays and RNASeq. Compared to normal pancreatic samples, PDL1 expression was upregulated in 19% of cancer samples. Upregulation was not associated with clinicopathological features such as patients' age and sex, pathological type, tumor size, lymph node status, and grade, but was associated with shorter disease-free survival and overall survival in multivariate analyses. Analysis of correlations with biological parameters showed that PDL1 upregulation was associated with some degree of lymphocyte infiltration and signs of anti-tumor T-cell response, but to a lesser extent than what has been reported in breast cancer and GIST. PDL1-up pancreatic cancers displayed profiles of lymphocyte exhaustion, were more enriched in inhibitory molecules and pro-tumor populations (Tregs with upregulation of FOXP3 and IL10, myeloid-derived suppressor cells with upregulation of CD33 and S100A8/A9), and demonstrated a down-modulation of most MHC class I members (HLA-A/B/C, HLA-E/F/G) suggestive of a defect in antigen processing and presentation. In conclusion, our results suggest that PDL1 expression might refine the prediction of metastatic relapse in operated pancreatic cancer, and that PD1/PDL1 inhibitors might reactivate inhibited T-cells to increase the anti-tumor immune response in PDL1-upregulated tumors.

Cholecystokinin receptor antagonist alters pancreatic cancer microenvironment and increases efficacy of immune checkpoint antibody therapy in mice

Advanced pancreatic ductal adenocarcinoma (PDAC) has typically been resistant to chemotherapy and immunotherapy; therefore, novel strategies are needed to enhance therapeutic response. Cholecystokinin (CCK) has been shown to stimulate growth of pancreatic cancer. CCK receptors (CCKRs) are present on pancreatic cancer cells, fibroblasts, and lymphocytes. We hypothesized that CCKR blockade would improve response to immune checkpoint antibodies by promoting influx of tumor-infiltrating lymphocytes (TILs) and reducing fibrosis. We examined the effects of CCKR antagonists or immune checkpoint blockade antibodies alone or in combination in murine models of PDAC. Monotherapy with CCKR blockade significantly decreased tumor size and metastases in SCID mice with orthotopic PDAC, and in C57BL/6 mice, it reduced fibrosis and induced the influx of TILs. Immune-competent mice bearing syngeneic pancreatic cancer (Panc02 and mT3-2D) that were treated with the combination of CCK receptor antagonists and immune checkpoint blockade antibodies survived significantly longer with smaller tumors. Tumor immunohistochemical staining and flow cytometry demonstrated that the tumors of mice treated with the combination regimen had a significant reduction in Foxp3+ T-regulatory cells and an increase in CD4+ and CD8+ lymphocytes. Masson's trichrome stain analysis revealed 50% less fibrosis in the tumors of mice treated with CCKR antagonist compared to controls and compared to checkpoint antibody therapy. CCKR antagonists given with immune checkpoint antibody therapy represent a novel approach for improving survival of PDAC. The mechanism by which this combination therapy improves the survival of PDAC may be related to the decreased fibrosis and immune cells of the tumor microenvironment.

Immunodeficiency in Pancreatic Adenocarcinoma with Diabetes Revealed by Comparative Genomics

Purpose: Pancreatic adenocarcinomas (PAAD) often are not diagnosed until their late stages, leaving no effective treatments. Currently, immunotherapy provides a promising treatment option against this malignancy. However, a set of immunotherapy agents benefit patients with many types of cancer, but not PAAD. Sharing the origin in the same organ, diabetes and PAAD tend to occur concurrently. We aimed to identify the impact of diabetes on immunotherapy of PAAD by conducting a comparative genomics analysis.Experimental Design: We analyzed level 3 PAAD genomics data (RNAseq, miRNAseq, DNA methylation, somatic copy number, and somatic mutation) from The Cancer Genome Atlas (TCGA) and Firehose. The differential molecular profiles in PAAD with/out diabetes were performed by the differential gene expression, pathway analysis, epigenetic regulation, somatic copy-number alteration, and somatic gene mutation.Results: Differential gene expression analysis revealed a strong enrichment of immunogenic signature genes in diabetic individuals, including PD-1 and CTLA4, that were currently targetable for immunotherapy. Pathway analysis further implied that diabetic individuals were defective in immune modulation genes. Somatic copy-number aberration (SCNA) analysis showed a higher frequency of amplification and deletion occurred in the cohort without diabetes. Integrative analysis revealed strong association between differential gene expression, and epigenetic regulations, however, seemed not affected by SCNAs. Importantly, our somatic mutation analysis showed that the occurrence of diabetes in PAAD was associated with a large set of gene mutations encoding genes participating in immune modulation.Conclusions: Our analysis reveals the impact of diabetes on immunodeficiency in PAAD patients and provides novel insights into new therapeutic opportunities. Clin Cancer Res; 23(20); 6363-73. ©2017 AACR.

Validation of Lymphocyte-to-Monocyte Ratio as a Prognostic Factor in Advanced Pancreatic Cancer: An East Asian Cohort Study of 2 Countries

OBJECTIVES

Although the prognostic value of lymphocyte-to-monocyte ratio (LMR) has been recently demonstrated in solid tumors, little is known of its impact on advanced pancreatic cancer (APC). This study evaluates and validates the cutoff value of LMR for predicting palliative chemotherapy outcome using a transnational cohort of APC patients.

METHODS

A total of 405 APC patients receiving first-line palliative chemotherapy were retrospectively reviewed. Of these, 153 patients were from Shanghai General Hospital (training set) and 252 patients were from Kyoto University Hospital (validation set). The optimal cutoff value of LMR was determined by a generating receiver operating characteristic curve for the training set. The association between LMR and survival was evaluated using log-rank tests, and a Cox regression model was used to validate the independent prognostic significance of LMR in APC patients.

RESULTS

The optimal cutoff value of LMR was 2.8. Overall survival was significantly longer in patients with LMR of 2.8 or greater than those with LMR of less than 2.8 (P < 0.001). Cox regression analysis showed that LMR was an independent prognostic factor. The impact of LMR was widely observed in all subgroups except the performance status 2 subgroup.

CONCLUSIONS

Lymphocyte-to-monocyte ratio may be considered as a promising prognostic marker for APC patients receiving palliative chemotherapy.

Interleukin-15 stimulates natural killer cell-mediated killing of both human pancreatic cancer and stellate cells

Pancreatic ductal adenocarcinoma (PDAC) is the 4^th leading cause of cancer-related death in Western countries with a 5-year survival rate below 5%. One of the hallmarks of this cancer is the strong desmoplastic reaction within the tumor microenvironment (TME), orchestrated by activated pancreatic stellate cells (PSC). This results in a functional and mechanical shield which causes resistance to conventional therapies. Aiming to overcome this resistance by tackling the stromal shield, we assessed for the first time the capacity of IL-15 stimulated natural killer (NK) cells to kill PSC and pancreatic cancer cells (PCC). The potency of IL-15 to promote NK cell-mediated killing was evaluated phenotypically and functionally. In addition, NK cell and immune checkpoint ligands on PSC were charted. We demonstrate that IL-15 activated NK cells kill both PCC and PSC lines (range 9-35% and 20-50%, respectively) in a contact-dependent manner and significantly higher as compared to resting NK cells. Improved killing of these pancreatic cell lines is, at least partly, dependent on IL-15 induced upregulation of TIM-3 and NKG2D. Furthermore, we confirm significant killing of primary PSC by IL-15 activated NK cells in an ex vivo autologous system. Screening for potential targets for immunotherapeutic strategies, we demonstrate surface expression of both inhibitory (PD-L1, PD-L2) and activating (MICA/B, ULBPs and Galectin-9) ligands on primary PSC. These data underscore the therapeutic potential of IL-15 to promote NK cell-mediated cytotoxicity as a treatment of pancreatic cancer and provide promising future targets to tackle remaining PSC.

Efficacy of vaccination with tumor-exosome loaded dendritic cells combined with cytotoxic drug treatment in pancreatic cancer

Pancreatic cancer (PaCa) has a dismal prognosis and adjuvant immunotherapy frequently is of low efficacy due to immunosuppressive features of PaCa and PaCa-stroma. We here explored, whether the efficacy of vaccination with tumor-exosome (TEX)-loaded dendritic cells (DC) can be improved by combining with drugs affecting myeloid-derived suppressor cells (MDSC). Experiments were performed with the UNKC6141 PaCa line. UNKC6141 TEX-loaded DC were weekly intravenously injected, mice additionally receiving Gemcitabine (GEM) and/or ATRA and/or Sunitinib (Sun). UNKC6141 grow aggressively after subcutaneous and orthotopic application and are consistently recovered in peripheral blood, bone marrow, lung and frequently liver. Vaccination with DC-TEX significantly prolonged the survival time, the efficacy of DC-TEX exceeding that of the cytotoxic drugs. However, ATRA, Sun and most efficiently GEM, sufficed for a pronounced reduction of MDSC including tumor-infiltrating MDSC, which was accompanied by a decrease in migrating and metastasizing tumor cells. When combined with DC-TEX vaccination, a higher number of activated T cells was recovered in the tumor and the survival time was prolonged compared with only DC-TEX vaccinated mice. As ATRA, GEM and Sun affect MDSC at distinct maturation and activation stages, a stronger support for DC-TEX vaccination was expected by the drug combination. Intrapancreatic tumor growth was prevented beyond the death of control mice. However, tumors developed after a partial breakdown of the immune system by the persisting drug application. Nonetheless, in combination with optimized drug tuning to prevent MDSC maturation and activation, vaccination with TEX-loaded DC appears a most promising option in PaCa therapy.

Differentiated State of Initiating Tumor Cells Is Key to Distinctive Immune Responses Seen in H-RasG12V-Induced Squamous Tumors

Heterogeneity in tumor immune responses is a poorly understood yet critical parameter for successful immunotherapy. In two doxycycline-inducible models where oncogenic H-Ras^G12V is targeted either to the epidermal basal/stem cell layer with a Keratin14-rtTA transgene (K14Ras), or committed progenitor/suprabasal cells with an Involucrin-tTA transgene (InvRas), we observed strikingly distinct tumor immune responses. On threshold doxycycline levels yielding similar Ras expression, tumor latency, and numbers, tumors from K14Ras mice had an immunosuppressed microenvironment, whereas InvRas tumors had a proinflammatory microenvironment. On a Rag1^-/- background, InvRas mice developed fewer and smaller tumors that regressed over time, whereas K14Ras mice developed more tumors with shorter latency than Rag1^+/+ controls. Adoptive transfer and depletion studies revealed that B-cell and CD4 T-cell cooperation was critical for tumor yield, lymphocyte polarization, and tumor immune phenotype in Rag1^+/+ mice of both models. Coculture of tumor-conditioned B cells with CD4 T cells implicated direct contact for Th1 and regulatory T cell (Treg) polarization, and CD40-CD40L for Th1, Th2, and Treg generation, a response not observed from splenic B cells. Anti-CD40L caused regression of InvRas tumors but enhanced growth in K14Ras, whereas a CD40 agonist mAb had opposite effects in each tumor model. These data show that position of tumor-initiating cells within a stratified squamous epithelial tissue provokes distinct B- and CD4 T-cell interactions, which establish unique tumor microenvironments that regulate tumor development and response to immunotherapy. Cancer Immunol Res; 5(3); 198-210. ©2017 AACR.

Role of immune cells in pancreatic cancer from bench to clinical application: An updated review

BACKGROUND

Pancreatic cancer (PC) remains difficult to treat, despite the recent advances in various anticancer therapies. Immuno-inflammatory response is considered to be a major risk factor for the development of PC in addition to a combination of genetic background and environmental factors. Although patients with PC exhibit evidence of systemic immune dysfunction, the PC microenvironment is replete with immune cells.

METHODS

We searched PubMed for all relevant English language articles published up to March 2016. They included clinical trials, experimental studies, observational studies, and reviews. Trials enrolled at Clinical trial.gov were also searched.

RESULTS

PC induces an immunosuppressive microenvironment, and intratumoral activation of immunity in PC is attenuated by inhibitory signals that limit immune effector function. Multiple types of immune responses can promote an immunosuppressive microenvironment; key regulators of the host tumor immune response are dendritic cells, natural killer cells, macrophages, myeloid derived suppressor cells, and T cells. The function of these immune cells in PC is also influenced by chemotherapeutic agents and the components in tumor microenvironment such as pancreatic stellate cells. Immunotherapy of PC employs monoclonal antibodies/effector cells generated in vitro or vaccination to stimulate antitumor response. Immune therapy in PC has failed to improve overall survival; however, combination therapies comprising immune checkpoint inhibitors and vaccines have been attempted to increase the response.

CONCLUSION

A number of studies have begun to elucidate the roles of immune cell subtypes and their capacity to function or dysfunction in the tumor microenvironment of PC. It will not be long before immune therapy for PC becomes a clinical reality.

Human Pancreatic Cancer Cells Induce a MyD88-Dependent Stromal Response to Promote a Tumor-Tolerant Immune Microenvironment

Cancer cells exert mastery over the local tumor-associated stroma (TAS) to configure protective immunity within the tumor microenvironment. The immunomodulatory character of pancreatic lysates of patients with cancer differs from those with pancreatitis. In this study, we evaluated the cross-talk between pancreatic cancer and its TAS in primary human cell culture models. Upon exposure of TAS to pancreatic cancer cell-conditioned media, we documented robust secretion of IL6 and IL8. This TAS response was MyD88-dependent and sufficient to directly suppress both CD4⁺ and CD8⁺ T-cell proliferation, inducing Th17 polarization at the expense of Th1. We found that patients possessed a similar shift in circulating effector memory Th17:Th1 ratios compared with healthy controls. The TAS response also directly suppressed CD8⁺ T-cell-mediated cytotoxicity. Overall, our results demonstrate how TAS contributes to the production of an immunosuppressive tumor microenvironment in pancreatic cancer. Cancer Res; 77(3); 672-83. ©2016 AACR.

Current Status of Immunotherapy Treatments for Pancreatic Cancer

Pancreatic cancer (PC) is a lethal disease representing the seventh most frequent cause of death from cancer worldwide. Resistance of pancreatic tumors to current treatments leads to disappointing survival rates, and more specific and effective therapies are urgently needed. In recent years, immunotherapy has been proposed as a promising approach to the treatment of PC, and encouraging results have been published by various preclinical and clinical studies. This review provides an overview of the latest developments in the immunotherapeutic treatment of PC and summarizes the most recent and important clinical trials.