Understanding the immune response and the current landscape of immunotherapy in pancreatic cancer

Frontiers and future of immunotherapy for pancreatic cancer: from molecular mechanisms to clinical application

Pancreatic cancer is a highly aggressive malignant tumor, that is becoming increasingly common in recent years. Despite advances in intensive treatment modalities including surgery, radiotherapy, biological therapy, and targeted therapy, the overall survival rate has not significantly improved in patients with pancreatic cancer. This may be attributed to the insidious onset, unknown pathophysiology, and poor prognosis of the disease. It is therefore essential to identify and develop more effective and safer treatments for pancreatic cancer. Tumor immunotherapy is the new and fourth pillar of anti-tumor therapy after surgery, radiotherapy, and chemotherapy. Significant progress has made in the use of immunotherapy for a wide variety of malignant tumors in recent years; a breakthrough has also been made in the treatment of pancreatic cancer. This review describes the advances in immune checkpoint inhibitors, cancer vaccines, adoptive cell therapy, oncolytic virus, and matrix-depletion therapies for the treatment of pancreatic cancer. At the same time, some new potential biomarkers and potential immunotherapy combinations for pancreatic cancer are discussed. The molecular mechanisms of various immunotherapies have also been elucidated, and their clinical applications have been highlighted. The current challenges associated with immunotherapy and proposed strategies that hold promise in overcoming these limitations have also been discussed, with the aim of offering new insights into immunotherapy for pancreatic cancer.

Development of a customizable mouse backbone spectral flow cytometry panel to delineate immune cell populations in normal and tumor tissues

Introduction

In vivo studies of cancer biology and assessment of therapeutic efficacy are critical to advancing cancer research and ultimately improving patient outcomes. Murine cancer models have proven to be an invaluable tool in pre-clinical studies. In this context, multi-parameter flow cytometry is a powerful method for elucidating the profile of immune cells within the tumor microenvironment and/or play a role in hematological diseases. However, designing an appropriate multi-parameter panel to comprehensively profile the increasing diversity of immune cells across different murine tissues can be extremely challenging.

Methods

To address this issue, we designed a panel with 13 fixed markers that define the major immune populations -referred to as the backbone panel- that can be profiled in different tissues but with the option to incorporate up to seven additional fluorochromes, including any marker specific to the study in question.

Results

This backbone panel maintains its resolution across different spectral flow cytometers and organs, both hematopoietic and non-hematopoietic, as well as tumors with complex immune microenvironments.

Discussion

Having a robust backbone that can be easily customized with pre-validated drop-in fluorochromes saves time and resources and brings consistency and standardization, making it a versatile solution for immuno-oncology researchers. In addition, the approach presented here can serve as a guide to develop similar types of customizable backbone panels for different research questions requiring high-parameter flow cytometry panels.

Polyphenol Supplementation Enhances the Efficacy of PD-1/PD-L1 Inhibitors Against Cancer: A Meta-Analysis of Animal Studies

BACKGROUND

This study performed a meta-analysis to evaluate the combined effects of polyphenols and anti-programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) inhibitors.

METHODS

Relevant studies were collected from electronic databases. Standardized mean differences (SMDs) or hazard ratio (HR) was calculated by Stata 15.0 software.

RESULTS

Sixteen preclinical studies were included. The overall meta-analysis showed that, compared to anti-PD-1/PD-L1 alone, polyphenol combined therapy significantly reduced the tumor volume (SMD = -3.28), weight (SMD = -2.18), number (SMD = -2.17), and prolonged the survival (HR = 0.45) of mice (all P < 0.001). Pooled analysis of mechanism studies indicated polyphenol combined therapy could increase the number of cytotoxic CD8+ T cells (SMD = 3.88; P < 0.001), IFN-γ+ CD8+ T cells (SMD = 2.38; P < 0.001), decrease the number of myeloid-derived suppressor cells (SMD = -2.52; P = 0.044) and Treg cells (SMD = -4.00; P = 0.004) and suppress PD-L1 expression in tumors (SMD = -13.41; P < 0.001). Subgroup analyses demonstrated curcuminoids, flavonoids, and stilbene changed the tumor volume, the percentage of CD8+ T cells, IFN-γ+CD8+ T cells, and PD-L1 expression.

CONCLUSION

Polyphenol supplementation may be a promising combined strategy for patients with poor response to anti-PD-1/PD-L1 monotherapy.

Expression of miR-425-5p in Pancreatic Carcinoma and Its Correlation with Tumor Immune Microenvironment

Background: Pancreatic carcinoma (PC) is a global health threat with a high death rate. miRNAs are implicated in tumor initiation and progression. This study explored the expression of miR-425-5p in PC patients and its correlation with tumor immune microenvironment (TIME).Method: miR-425-5p expression in cancer tissues and adjacent non-tumor tissues of PC patients was examined by RT-qPCR. The levels of immune cells and cytokines were measured by flow cytometry and ELISA. The correlation of miR-425-5p with TNM stage and TIME was assessed by Spearman method. The death of PC patients was recorded through 36-month follow-ups. The prognosis of patients was assessed by Kaplan-Meier curves.Results: miR-425-5p expression was upregulated in PC tissues and elevated with increasing TNM stage. miR-425-5p expression was positively correlated with TNM stage. The PC tissues had decreased levels of CD3+, CD4+, CD8+, and natural killer (NK) cells, CD4+/CD8+ ratio, IL-2, and INF-γ, but increased levels of Tregs, IL-4, IL-10, and TGF-β. miR-425-5p level in cancer tissues was positively correlated with Tregs/IL-10/TGF-β, but negatively related to CD3+/CD4+/CD8+/NK cells and IL-2/INF-γ. Moreover, high miR-425-5p expression predicted a poor prognosis in PC patients.Conclusion: miR-425-5p is upregulated in PC patients and is prominently associated with the TIME, and high miR-425-5p predicts a poor prognosis in PC patients.

Improving the prognosis of pancreatic cancer: insights from epidemiology, genomic alterations, and therapeutic challenges

Pancreatic cancer, notorious for its late diagnosis and aggressive progression, poses a substantial challenge owing to scarce treatment alternatives. This review endeavors to furnish a holistic insight into pancreatic cancer, encompassing its epidemiology, genomic characterization, risk factors, diagnosis, therapeutic strategies, and treatment resistance mechanisms. We delve into identifying risk factors, including genetic predisposition and environmental exposures, and explore recent research advancements in precursor lesions and molecular subtypes of pancreatic cancer. Additionally, we highlight the development and application of multi-omics approaches in pancreatic cancer research and discuss the latest combinations of pancreatic cancer biomarkers and their efficacy. We also dissect the primary mechanisms underlying treatment resistance in this malignancy, illustrating the latest therapeutic options and advancements in the field. Conclusively, we accentuate the urgent demand for more extensive research to enhance the prognosis for pancreatic cancer patients.

Pancreatic cancer challenge in 52 Asian countries: age-centric insights and the role of modifiable risk factors (1990-2019)

Background

Pancreatic cancer is renowned for its elevated incidence and mortality rates on a global scale. The disease burden of pancreatic cancer is anticipated to increase, particularly in Asia, due to its vast and rapidly aging population.

Methods

Data from the Global Burden of Disease 2019 were analyzed for pancreatic cancer burden across 52 countries in Asia, including the incidence, mortality, and disability-adjusted life years (DALY) for pancreatic cancer, with a focus on risk factors such as high body mass index (BMI), elevated fasting plasma glucose, and smoking. We applied the Estimated Annual Percentage Change, the Age-Period-Cohort model, and decomposition analysis to evaluate incidence trends and effects.

Results

From 1990 to 2019, both incidence and mortality rates of pancreatic cancer in Asia significantly increased, with an average annual standardized incidence rate change of 1.73%. Males consistently exhibited higher rates than females, with smoking as a key risk factor. Central Asia reported the highest rates, and South Asia the lowest. The incidence rose with age, peaking in those aged 70~74. The disease burden increased in all age groups, particularly in populations aged 55 and above, representing 84.41% of total cases in 2019, up from 79.01% in 1990. Pancreatic cancer ranked the fifth in incidence among six major gastrointestinal tumors but presented a significant growth rate of mortality and DALY.

Conclusion

With the growing, aging population in Asia, the pancreatic cancer burden is projected to escalate, bringing a significant public health challenge. Hence, comprehensive public health strategies emphasizing early detection, risk modification, and optimized treatment of pancreatic cancer are imperative.

Suppression of the antitumoral activity of natural killer cells under indirect coculture with cancer-associated fibroblasts in a pancreatic TIME-on-chip model

BACKGROUND

Recently, natural killer (NK) cells emerged as a treatment option for various solid tumors. However, the immunosuppressive tumor immune microenvironment (TIME) can reduce the cytotoxic ability of NK cells in pancreatic ductal adenocarcinoma. Cancer-associated fibroblasts within the tumor stroma can suppress immune surveillance by dysregulating factors involved in the cellular activity of NK cells. Herein, the effect of activated pancreatic stellate cells (aPSCs) on NK cell-mediated anticancer efficacy under three-dimensional (3D) coculture conditions was investigated.

METHODS

3D cocultures of PANC-1 tumor spheroids (TSs) with aPSCs and NK-92 cells in a collagen matrix were optimized to identify the occurring cellular interactions and differential cytokine profiles in conditioned media using microchannel chips. PANC-1 TSs and aPSCs were indirectly cocultured, whereas NK-92 cells were allowed to infiltrate the TS channel using convective medium flow.

RESULTS

Coculture with aPSCs promoted PANC-1 TSs growth and suppressed the antitumor cytotoxic effects of NK-92 cells. Mutual inhibition of cellular activity without compromising migration ability was observed between aPSCs and NK-92 cells. Moreover, the reduced killing activity of NK-92 cells was found to be related with reduced granzyme B expression in NK cells.

CONCLUSIONS

Herein, a novel TIME-on-chip model based on the coculture of PANC-1 TSs, aPSCs, and NK-92 cells was described. This model may be useful for studying the detailed mechanisms underlying NK cells dysregulation and for exploring future therapeutic interventions to restore NK cell activity in the tumor microenvironment.

Time trend of pancreatic cancer mortality in the Western Pacific Region: age-period-cohort analysis from 1990 to 2019 and forecasting for 2044

BACKGROUND

Pancreatic cancer poses a serious medical problem worldwide. Countries in the Western Pacific Region are facing public health challenges from cancer. This study assesses the time trends of pancreatic cancer mortality in the Western Pacific Region from 1990 to 2019 and predicts its trend to 2044.

METHODS

Mortality data were obtained from the Global Health Data Exchange. We used an age-period-cohort model to estimate age, period and birth cohort effects on pancreatic cancer mortality from 1990 to 2019 by calculating net drift, local drift, age-specific rate, period rate ratio, and cohort rate ratio. We also predict pancreatic cancer mortality to 2044 in Western Pacific countries.

RESULTS

Overall, there were 178,276 (95% uncertain interval: 157,771 to 198,636) pancreatic cancer deaths in the Western Pacific Region in 2019, accounting for 33.6% of all deaths due to pancreatic cancer worldwide. There were significant increases in pancreatic cancer disability-adjusted life years between 1990 and 2019 in the Western Pacific Region, mainly due to population growth and aging. Pancreatic cancer mortality increased with age. The period effect showed an increasing trend of mortality for both sexes over the study period. Compared to the reference period (2000 to 2004), the rate ratio was elevated in both males and females in the period of 2015 to 2019. There was an overall increasing rate ratio from early birth cohorts to recent cohorts. Deaths may continue to increase in the next 25 years in the ten countries, while most countries have seen their age-standardized rate forecasts fall.

CONCLUSION

The mortality of pancreatic cancer is still high in the Western Pacific Region. Countries/territories should focus on pancreatic cancer prevention and early cancer screening in high-risk populations. Specific public health methods and policies aimed at reducing risk factors for pancreatic cancer are also needed.

The clinical terrain of immunotherapies in heterogeneous pancreatic cancer: unravelling challenges and opportunities

Pancreatic ductal adenocarcinoma (PDAC) is the most common and aggressive type of pancreatic cancer and has abysmal survival rates. In the past two decades, immunotherapeutic agents with success in other cancer types have gradually been trialled against PDACs at different stages of cancer progression, either as a monotherapy or in combination with chemotherapy. Unfortunately, to this day, chemotherapy still prolongs the survival rates the most and is prescribed in clinics despite the severe side effects in other cancer types. The low success rates of immunotherapy against PDAC have been attributed most frequently to its complex and multi-faceted tumour microenvironment (TME) and low mutational burden. In this review, we give a comprehensive overview of the immunotherapies tested in PDAC clinical trials thus far, their limitations, and potential explanations for their failure. We also discuss the existing classification of heterogenous PDACs into cancer, cancer-associated fibroblast, and immune subtypes and their potential opportunity in patient selection as a form of personalisation of PDAC immunotherapy. © 2023 The Pathological Society of Great Britain and Ireland.

Analysis of M2 macrophage-associated risk score signature in pancreatic cancer TME landscape and immunotherapy

Background: M2 macrophages perform an influential role in the progression of pancreatic cancer. This study is dedicated to explore the value of M2 macrophage-related genes in the treatment and prognosis of pancreatic cancer. Methods: RNA-Seq and clinical information were downloaded from TCGA, GEO and ICGC databases. The pancreatic cancer tumour microenvironment was revealed using the CIBERSORT algorithm. Weighted gene co-expression network analysis (WGCNA) was used to detect M2 macrophage-associated gene modules. Univariate Cox regression, Least absolute shrinkage and selection operator (LASSO) regression analysis and multivariate Cox regression were applied to develop the prognostic model. The modelling and validation cohorts were divided into high-risk and low-risk groups according to the median risk score. The nomogram predicting survival was constructed based on risk scores. Correlations between risk scores and tumour mutational load, clinical variables, immune checkpoint blockade, and immune cells were further explored. Finally, potential associations between different risk models and chemotherapeutic agent efficacy were predicted. Results: The intersection of the WGCNA results from the TCGA and GEO data screened for 317 M2 macrophage-associated genes. Nine genes were identified by multivariate COX regression analysis and applied to the construction of risk models. The results of GSEA analysis revealed that most of these genes were related to signaling, cytokine receptor interaction and immunodeficiency pathways. The high and low risk groups were closely associated with tumour mutational burden, immune checkpoint blockade related genes, and immune cells. The maximum inhibitory concentrations of metformin, paclitaxel, and rufatinib lapatinib were significantly differences on the two risk groups. Conclusion: WGCNA-based analysis of M2 macrophage-associated genes can help predict the prognosis of pancreatic cancer patients and may provide new options for immunotherapy of pancreatic cancer.

A Comprehensive Transcriptional Signature in Pancreatic Ductal Adenocarcinoma Reveals New Insights into the Immune and Desmoplastic Microenvironments

Pancreatic ductal adenocarcinoma (PDAC) prognoses and treatment responses remain devastatingly poor due partly to the highly heterogeneous, aggressive, and immunosuppressive nature of this tumor type. The intricate relationship between the stroma, inflammation, and immunity remains vaguely understood in the PDAC microenvironment. Here, we performed a meta-analysis of stroma-, and immune-related gene expression in the PDAC microenvironment to improve disease prognosis and therapeutic development. We selected 21 PDAC studies from the Gene Expression Omnibus and ArrayExpress databases, including 922 samples (320 controls and 602 cases). Differential gene enrichment analysis identified 1153 significant dysregulated genes in PDAC patients that contribute to a desmoplastic stroma and an immunosuppressive environment (the hallmarks of PDAC tumors). The results highlighted two gene signatures related to the immune and stromal environments that cluster PDAC patients into high- and low-risk groups, impacting patients' stratification and therapeutic decision making. Moreover, HCP5, SLFN13, IRF9, IFIT2, and IFI35 immune genes are related to the prognosis of PDAC patients for the first time.

Immunosuppression, immune escape, and immunotherapy in pancreatic cancer: focused on the tumor microenvironment

Pancreatic ductal adenocarcinoma (PDAC), the most common type of pancreatic cancer, is characterized by poor treatment response and low survival time. The current clinical treatment for advanced PDAC is still not effective. In recent years, the research and application of immunotherapy have developed rapidly and achieved substantial results in many malignant tumors. However, the translational application in PDAC is still far from satisfactory and needs to be developed urgently. To carry out the study of immunotherapy, it is necessary to fully decipher the immune characteristics of PDAC. This review summarizes the recent progress of the tumor microenvironment (TME) of PDAC and highlights its link with immunotherapy. We describe the molecular cues and corresponding intervention methods, collate several promising targets and progress worthy of further study, and put forward the importance of integrated immunotherapy to provide ideas for future research of TME and immunotherapy of PDAC.

Quantitative Spatial Profiling of Immune Populations in Pancreatic Ductal Adenocarcinoma Reveals Tumor Microenvironment Heterogeneity and Prognostic Biomarkers

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with poor 5-year survival rates, necessitating identification of novel therapeutic targets. Elucidating the biology of the tumor immune microenvironment (TiME) can provide vital insights into mechanisms of tumor progression. In this study, we developed a quantitative image processing platform to analyze sequential multiplexed IHC data from archival PDAC tissue resection specimens. A 27-plex marker panel was employed to simultaneously phenotype cell populations and their functional states, followed by a computational workflow to interrogate the immune contextures of the TiME in search of potential biomarkers. The PDAC TiME reflected a low-immunogenic ecosystem with both high intratumoral and intertumoral heterogeneity. Spatial analysis revealed that the relative distance between IL10+ myelomonocytes, PD-1+ CD4+ T cells, and granzyme B+ CD8+ T cells correlated significantly with survival, from which a spatial proximity signature termed imRS was derived that correlated with PDAC patient survival. Furthermore, spatial enrichment of CD8+ T cells in lymphoid aggregates was also linked to improved survival. Altogether, these findings indicate that the PDAC TiME, generally considered immuno-dormant or immunosuppressive, is a spatially nuanced ecosystem orchestrated by ordered immune hierarchies. This new understanding of spatial complexity may guide novel treatment strategies for PDAC.

SIGNIFICANCE

Quantitative image analysis of PDAC specimens reveals intertumoral and intratumoral heterogeneity of immune populations and identifies spatial immune architectures that are significantly associated with disease prognosis.