Mechanisms Governing Immunotherapy Resistance in Pancreatic Ductal Adenocarcinoma

NPC1L1 on pancreatic adenocarcinoma cell functions as a two-pronged checkpoint against antitumor activity

Pancreatic adenocarcinoma (PAAD) is a highly lethal malignancy with an immunosuppressive microenvironment and a limited immunotherapy response. Cholesterol is necessary for rapid growth of cancer cells, and cholesterol metabolism reprogramming is a hallmark of PAAD. How PAAD cells initiate cholesterol reprogramming to sustain their growth demand and suppressive immunomicroenvironment remains elusive. In this study, we for the first time revealed that PAAD cells overcome cholesterol shortage and immune surveillance via ectopically overexpressing NPC1L1, a cholesterol transporter, but function as a two-pronged checkpoint, which not only directly suppresses TCR activation of CD8+T cells but also hijacks the intracellular cholesterol from CD8+T cells. In vivo, we showed that ezetimibe, an NPC1L1 inhibitor usually for hypercholesterolemia, efficiently prevented PAAD cells from depriving cholesterol of CD8+T cells, and improved the anti-tumor immunity of PAAD to synergize with PD-1 blockade, suggesting NPC1L1 as a promising target to rescue the anti-tumor activity in PAAD.

Macrophage Migration Inhibitory Factor (MIF) and D-Dopachrome Tautomerase (DDT): Pathways to Tumorigenesis and Therapeutic Opportunities

Discovered as inflammatory cytokines, MIF and DDT exhibit widespread expression and have emerged as critical mediators in the response to infection, inflammation, and more recently, in cancer. In this comprehensive review, we provide details on their structures, binding partners, regulatory mechanisms, and roles in cancer. We also elaborate on their significant impact in driving tumorigenesis across various cancer types, supported by extensive in vitro, in vivo, bioinformatic, and clinical studies. To date, only a limited number of clinical trials have explored MIF as a therapeutic target in cancer patients, and DDT has not been evaluated. The ongoing pursuit of optimal strategies for targeting MIF and DDT highlights their potential as promising antitumor candidates. Dual inhibition of MIF and DDT may allow for the most effective suppression of canonical and non-canonical signaling pathways, warranting further investigations and clinical exploration.

New avenues for the treatment of immunotherapy-resistant pancreatic cancer

Pancreatic cancer (PC) is characterized by its extremely aggressive nature and ranks 14th in the number of new cancer cases worldwide. However, due to its complexity, it ranks 7th in the list of the most lethal cancers worldwide. The pathogenesis of PC involves several complex processes, including familial genetic factors associated with risk factors such as obesity, diabetes mellitus, chronic pancreatitis, and smoking. Mutations in genes such as KRAS, TP53, and SMAD4 are linked to the appearance of malignant cells that generate pancreatic lesions and, consequently, cancer. In this context, some therapies are used for PC, one of which is immunotherapy, which is extremely promising in various other types of cancer but has shown little response in the treatment of PC due to various resistance mechanisms that contribute to a drop in immunotherapy efficiency. It is therefore clear that the tumor microenvironment (TME) has a huge impact on the resistance process, since cellular and non-cellular elements create an immunosuppressive environment, characterized by a dense desmoplastic stroma with cancer-associated fibroblasts, pancreatic stellate cells, extracellular matrix, and immunosuppressive cells. Linked to this are genetic mutations in TP53 and immunosuppressive factors that act on T cells, resulting in a shortage of CD8+ T cells and limited expression of activation markers such as interferon-gamma. In this way, finding new strategies that make it possible to manipulate resistance mechanisms is necessary. Thus, techniques such as the use of TME modulators that block receptors and stromal molecules that generate resistance, the use of genetic manipulation in specific regions, such as microRNAs, the modulation of extrinsic and intrinsic factors associated with T cells, and, above all, therapeutic models that combine these modulation techniques constitute the promising future of PC therapy. Thus, this study aims to elucidate the main mechanisms of resistance to immunotherapy in PC and new ways of manipulating this process, resulting in a more efficient therapy for cancer patients and, consequently, a reduction in the lethality of this aggressive cancer.

Treatment resistance in pancreatic and biliary tract cancer: molecular and clinical pharmacology perspectives

INTRODUCTION

Treatment resistance poses a significant obstacle in oncology, especially in biliary tract cancer (BTC) and pancreatic cancer (PC). Current therapeutic options include chemotherapy, targeted therapy, and immunotherapy. Resistance to these treatments may arise due to diverse molecular mechanisms, such as genetic and epigenetic modifications, altered drug metabolism and efflux, and changes in the tumor microenvironment. Identifying and overcoming these mechanisms is a major focus of research: strategies being explored include combination therapies, modulation of the tumor microenvironment, and personalized approaches.

AREAS COVERED

We provide a current overview and discussion of the most relevant mechanisms of resistance to chemotherapy, target therapy, and immunotherapy in both BTC and PC. Furthermore, we compare the different strategies that are being implemented to overcome these obstacles.

EXPERT OPINION

So far there is no unified theory on drug resistance and progress is limited. To overcome this issue, individualized patient approaches, possibly through liquid biopsies or single-cell transcriptome studies, are suggested, along with the potential use of artificial intelligence, to guide effective treatment strategies. Furthermore, we provide insights into what we consider the most promising areas of research, and we speculate on the future of managing treatment resistance to improve patient outcomes.

The β1-adrenergic receptor links sympathetic nerves to T cell exhaustion

CD8+ T cells are essential components of the immune response against viral infections and tumours, and are capable of eliminating infected and cancerous cells. However, when the antigen cannot be cleared, T cells enter a state known as exhaustion1. Although it is clear that chronic antigen contributes to CD8+ T cell exhaustion, less is known about how stress responses in tissues regulate T cell function. Here we show a new link between the stress-associated catecholamines and the progression of T cell exhaustion through the β1-adrenergic receptor ADRB1. We identify that exhausted CD8+ T cells increase ADRB1 expression and that exposure of ADRB1+ T cells to catecholamines suppresses their cytokine production and proliferation. Exhausted CD8+ T cells cluster around sympathetic nerves in an ADRB1-dependent manner. Ablation of β1-adrenergic signalling limits the progression of T cells towards the exhausted state in chronic infection and improves effector functions when combined with immune checkpoint blockade (ICB) in melanoma. In a pancreatic cancer model resistant to ICB, β-blockers and ICB synergize to boost CD8+ T cell responses and induce the development of tissue-resident memory-like T cells. Malignant disease is associated with increased catecholamine levels in patients2,3, and our results establish a connection between the sympathetic stress response, tissue innervation and T cell exhaustion. Here, we uncover a new mechanism by which blocking β-adrenergic signalling in CD8+ T cells rejuvenates anti-tumour functions.

Activin A-Mediated Polarization of Cancer-Associated Fibroblasts and Macrophages Confers Resistance to Checkpoint Immunotherapy in Skin Cancer

PURPOSE

Cemiplimab is approved for the treatment of locally advanced basal cell carcinomas (BCC), although with mitigated results. We sought to interrogate the cellular and molecular transcriptional reprogramming underlying BCC resistance to immunotherapy.

EXPERIMENTAL DESIGN

Here, we combined spatial and single-cell transcriptomics to deconvolute the spatial heterogeneity of the tumor microenvironment in regard with response to immunotherapy, in a cohort of both naïve and resistant BCCs.

RESULTS

We identified subsets of intermingled cancer-associated fibroblasts (CAF) and macrophages contributing the most to CD8 T-cell exclusion and immunosuppression. Within this spatially resolved peritumoral immunosuppressive niche, CAFs and adjacent macrophages were found to display Activin A-mediated transcriptional reprogramming towards extracellular matrix remodeling, suggesting active participation to CD8 T-cell exclusion. In independent datasets of human skin cancers, Activin A-conditioned CAFs and macrophages were associated with resistance to immune checkpoint inhibitors (ICI).

CONCLUSIONS

Altogether, our data identify the cellular and molecular plasticity of tumor microenvironment (TME) and the pivotal role of Activin A in polarizing the TME towards immune suppression and ICI resistance.

Obesity, cancer, and response to immune checkpoint inhibitors: Could the gut microbiota be the mechanistic link?

Immune checkpoint inhibitors (ICI) have deeply changed the therapeutic management of a broad spectrum of solid tumors. Recent observations showed that obese patients receiving ICIs might have better outcomes than those with normal weight, while obesity was historically associated with a worse prognosis in cancer patients. Of note, obesity is associated with alterations in the gut microbiome profile, which interacts with immune and inflammatory pathways, both at the systemic and intratumoral levels. As the influence of the gut microbiota on the response to ICI has been repeatedly reported, a specific gut microbiome profile in obese cancer patients may be involved in their better response to ICI. This review summarizes recent data on the interactions between obesity, gut microbiota, and ICIs. In addition, we highlight possible pathophysiological mechanisms supporting the hypothesis that gut microbiota could be one of the links between obesity and poor response to ICIs.

The Tango between Cancer-Associated Fibroblasts (CAFs) and Immune Cells in Affecting Immunotherapy Efficacy in Pancreatic Cancer

The lack of response to therapy in pancreatic ductal adenocarcinoma (PDAC) patients has contributed to PDAC having one of the lowest survival rates of all cancer types. The poor survival of PDAC patients urges the exploration of novel treatment strategies. Immunotherapy has shown promising results in several other cancer types, but it is still ineffective in PDAC. What sets PDAC apart from other cancer types is its tumour microenvironment (TME) with desmoplasia and low immune infiltration and activity. The most abundant cell type in the TME, cancer-associated fibroblasts (CAFs), could be instrumental in why low immunotherapy responses are observed. CAF heterogeneity and interactions with components of the TME is an emerging field of research, where many paths are to be explored. Understanding CAF-immune cell interactions in the TME might pave the way to optimize immunotherapy efficacy for PDAC and related cancers with stromal abundance. In this review, we discuss recent discoveries on the functions and interactions of CAFs and how targeting CAFs might improve immunotherapy.

Galectin-9 and PD-L1 antibody blockade combination therapy inhibits tumour progression in pancreatic cancer

Background: The study aimed to evaluate the effect of a galectin-9 and PD-L1 combined blockade in pancreatic ductal adenocarcinoma (PDAC). Methods: The expression of galectin-9 and PD-L1 was analyzed in PDAC. Furthermore, we explored the therapeutic effect of combined anti-galectin-9 and anti-PD-L1 therapy on pancreatic cancer in vivo. Results: Higher expression of galectin-9 and PD-L1 was observed in human PDAC compared with the normal pancreas. Furthermore, in a murine model of PDAC, combined anti-galectin-9 and anti-PD-L1 treatment was associated with a greater decrease in tumor growth compared with treatment with either antibody therapy alone. Conclusion: Anti-PD-L1 antibody treatment for PDAC patients may be enhanced by inhibiting galectin-9.

CD73 Inhibits cGAS-STING and Cooperates with CD39 to Promote Pancreatic Cancer

The ectonucleotidases CD39 and CD73 catalyze extracellular ATP to immunosuppressive adenosine, and as such, represent potential cancer targets. We investigated biological impacts of CD39 and CD73 in pancreatic ductal adenocarcinoma (PDAC) by studying clinical samples and experimental mouse tumors. Stromal CD39 and tumoral CD73 expression significantly associated with worse survival in human PDAC samples and abolished the favorable prognostic impact associated with the presence of tumor-infiltrating CD8+ T cells. In mouse transplanted KPC tumors, both CD39 and CD73 on myeloid cells, as well as CD73 on tumor cells, promoted polarization of infiltrating myeloid cells towards an M2-like phenotype, which enhanced tumor growth. CD39 on tumor-specific CD8+ T cells and pancreatic stellate cells also suppressed IFNγ production by T cells. Although therapeutic inhibition of CD39 or CD73 alone significantly delayed tumor growth in vivo, targeting of both ectonucleotidases exhibited markedly superior antitumor activity. CD73 expression on human and mouse PDAC tumor cells also protected against DNA damage induced by gemcitabine and irradiation. Accordingly, large-scale pharmacogenomic analyses of human PDAC cell lines revealed significant associations between CD73 expression and gemcitabine chemoresistance. Strikingly, increased DNA damage in CD73-deficient tumor cells associated with activation of the cGAS-STING pathway. Moreover, cGAS expression in mouse KPC tumor cells was required for antitumor activity of the CD73 inhibitor AB680 in vivo. Our study, thus, illuminates molecular mechanisms whereby CD73 and CD39 seemingly cooperate to promote PDAC progression.

Role of noncoding RNAs in pancreatic ductal adenocarcinoma associated cachexia

Cachexia is an acute syndrome that is very commonly observed in patients with cancer. Cachexia is the number one cause of death in patients with metastatic disease and is also the major factor for physical toxicity and financial burden. More importantly, the majority of patients with advanced-stage pancreatic ductal adenocarcinoma (PDAC) cancer undergo cachexia. Pancreatic cancer causes deaths of ∼50,000 Americans and about 400,000 people worldwide every year. The high mortality rates in metastatic PDAC are due to systemic pathologies and cachexia, which quickens death in these patients. About 90% of all patients with PDAC undergo wasting of muscle causing mobility loss and leading to a number of additional pathological conditions. PDAC-associated cancer cachexia emanates from complex signaling cues involving both mechanical and biological signals. Tumor invasion is associated with the loss of pancreatic function-induced digestive disorders and malabsorption, which causes subsequent weight loss and eventually promotes cachexia. Besides, systemic inflammation of patients with PDAC could release chemical cues (e.g., cytokine-mediated Atrogin-1/MAFbx expression) that participate in muscle wasting. Our understanding of genes, proteins, and cytokines involved in promoting cancer cachexia has evolved considerably. However, the role of epigenetic factors, particularly the role of noncoding RNAs (ncRNAs) in regulating PDAC-associated cachexia is less studied. In this review article, the most updated knowledge on the various ncRNAs including microRNAs (miRs), long noncoding RNA (lncRNAs), piwi interacting RNAs (PiwiRNAs), small nucleolar RNA (snoRNAs), and circular RNAs (circRNA) and their roles in cancer cachexia are described.

Facts and Hopes in Immunotherapy of Pancreatic Cancer

Pancreatic ductal adenocarcinoma (PDAC) remains one of the most challenging cancers to treat. For patients with advanced and metastatic disease, chemotherapy has yielded only modest incremental benefits, which are not durable. Immunotherapy has revolutionized the treatment of other solid tumors by leading to cures where none existed only a decade ago, yet it has made few inroads with PDAC. A host of trials with promising preclinical data have failed, except for in a small minority of patients with selected biomarkers. There is, however, a glimmer of hope, which we seek to cultivate. In this review, we discuss recent advances in the understanding of the uniquely immunosuppressive tumor microenvironment (TME) in PDAC, learnings from completed trials of checkpoint inhibitors, TME modifiers, cellular and vaccine therapies, oncolytic viruses, and other novel approaches. We go on to discuss our expectations for improved preclinical models of immunotherapy in PDAC, new approaches to modifying the TME including the myeloid compartment, and emerging biomarkers to better select patients who may benefit from immunotherapy. We also discuss improvements in clinical trial design specific to immunotherapy that will help us better measure success when we find it. Finally, we discuss the urgent imperative to better design and execute bold, but rational, combination trials of novel agents designed to cure patients with PDAC.

Multiscale anisotropy analysis of second-harmonic generation collagen imaging of human pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the deadliest cancers with a minority (< 10%) of patients surviving five years past diagnosis. This could be improved with the development of new imaging modalities for early differentiation of benign and cancerous fibrosis. This study intends to explore the application of a two-photon microscopy technique known as second harmonic generation to PDAC using the 2D Wavelet Transform Modulus Maxima (WTMM) Anisotropy method to quantify collagen organization in fibrotic pancreatic tissue. Forty slides from PDAC patients were obtained and eight images were captured per each tissue category on each slide. Brownian surface motion and white noise images were generated for calibration and testing of a new variable binning approach to the 2D WTMM Anisotropy method. The variable binning method had greater resistance to wavelet scaling effects and white noise images were found to have the lowest anisotropy factor. Cancer and fibrosis had greater anisotropy factors (Fa) at small wavelet scales than normal and normal adjacent tissue. At a larger scale of 21 μm this relationship changed with normal tissue having a higher Fa than all other tissue groups. White noise is the best representative image for isotropy and the 2D WTMM anisotropy method is sensitive to changes induced in collagen by PDAC.

Apigenin Targets MicroRNA-155, Enhances SHIP-1 Expression, and Augments Anti-Tumor Responses in Pancreatic Cancer

Pancreatic cancer (PC) is a deadly disease with a grim prognosis. Pancreatic tumor derived factors (TDF) contribute to the induction of an immunosuppressive tumor microenvironment (TME) that impedes the effectiveness of immunotherapy. PC-induced microRNA-155 (miRNA-155) represses expression of Src homology 2 (SH2) domain-containing Inositol 5'-phosphatase-1 (SHIP-1), a regulator of myeloid cell development and function, thus impacting anti-tumor immunity. We recently reported that the bioflavonoid apigenin (API) increased SHIP-1 expression which correlated with the expansion of tumoricidal macrophages (TAM) and improved anti-tumor immune responses in the TME of mice with PC. We now show that API transcriptionally regulates SHIP-1 expression via the suppression of miRNA-155, impacting anti-tumor immune responses in the bone marrow (BM) and TME of mice with PC. We discovered that API reduced miRNA-155 in the PC milieu, which induced SHIP-1 expression. This promoted the restoration of myelopoiesis and increased anti-tumor immune responses in the TME of heterotopic, orthotopic and transgenic SHIP-1 knockout preclinical mouse models of PC. Our results suggest that manipulating SHIP-1 through miR-155 may assist in augmenting anti-tumor immune responses and aid in the therapeutic intervention of PC.

Antibody-Based Approaches to Target Pancreatic Tumours

Pancreatic cancer is an aggressive cancer with a dismal prognosis. This is due to the difficulty to detect the disease at an early and curable stage. In addition, only limited treatment options are available, and they are confronted by mechanisms of resistance. Monoclonal antibody (mAb) molecules are highly specific biologics that can be directly used as a blocking agent or modified to deliver a drug payload depending on the desired outcome. They are widely used to target extracellular proteins, but they can also be employed to inhibit intracellular proteins, such as oncoproteins. While mAbs are a class of therapeutics that have been successfully employed to treat many cancers, they have shown only limited efficacy in pancreatic cancer as a monotherapy so far. In this review, we will discuss the challenges, opportunities and hopes to use mAbs for pancreatic cancer treatment, diagnostics and imagery.

Immunotherapy as a Therapeutic Strategy for Gastrointestinal Cancer-Current Treatment Options and Future Perspectives

Gastrointestinal (GI) cancer constitutes a highly lethal entity among malignancies in the last decades and is still a major challenge for cancer therapeutic options. Despite the current combinational treatment strategies, including chemotherapy, surgery, radiotherapy, and targeted therapies, the survival rates remain notably low for patients with advanced disease. A better knowledge of the molecular mechanisms that influence tumor progression and the development of optimal therapeutic strategies for GI malignancies are urgently needed. Currently, the development and the assessment of the efficacy of immunotherapeutic agents in GI cancer are in the spotlight of several clinical trials. Thus, several new modalities and combinational treatments with other anti-neoplastic agents have been identified and evaluated for their efficiency in cancer management, including immune checkpoint inhibitors, adoptive cell transfer, chimeric antigen receptor (CAR)-T cell therapy, cancer vaccines, and/or combinations thereof. Understanding the interrelation among the tumor microenvironment, cancer progression, and immune resistance is pivotal for the optimal therapeutic management of all gastrointestinal solid tumors. This review will shed light on the recent advances and future directions of immunotherapy for malignant tumors of the GI system.

Single-cell immunology: Past, present, and future

The immune system is a complex, dynamic, and plastic ecosystem composed of multiple cell types that constantly sense and interact with their local microenvironment to protect from infection and maintain homeostasis. For over a century, great efforts and ingenuity have been applied to the characterization of immune cells and their microenvironments, but traditional marker-based and bulk technologies left key questions unanswered. In the past decade, the advent of single-cell genomic approaches has revolutionized our knowledge of the cellular and molecular makeup of the immune system. In this perspective, we outline the past, present, and future applications of single-cell genomics in immunology and discuss how the integration of multiomics at the single-cell level will pave the way for future advances in immunology research and clinical translation.

Translational advances in pancreatic ductal adenocarcinoma therapy

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer that is most frequently detected at advanced stages, limiting treatment options to systemic chemotherapy with modest clinical responses. Here, we review recent advances in targeted therapy and immunotherapy for treating subtypes of PDAC with diverse molecular alterations. We focus on the current preclinical and clinical evidence supporting the potential of these approaches and the promise of combinatorial regimens to improve the lives of patients with PDAC.

Synergistic effect of Abraxane that combines human IL15 fused with an albumin-binding domain on murine models of pancreatic ductal adenocarcinoma

Nab‐paclitaxel (Abraxane), which is a nanoparticle form of albumin‐bound paclitaxel, is one of the standard chemotherapies for pancreatic ductal adenocarcinoma (PDAC). This study determined the effect of Abraxane in combination with a fusion protein, hIL15‐ABD, on subcutaneous Panc02 and orthotopic KPC C57BL/6 murine PDAC models. Abraxane combined with hIL15‐ABD best suppressed tumour growth and produced a 40%–60% reduction in the tumour size for Panc02 and KPC, compared to the vehicle group. In the combination group, the active form of interferon‐γ (IFN‐γ)‐secreting CD8⁺ T cells and CD11b⁺CD86⁺ M1 macrophages in tumour infiltrating lymphocytes (TILs) were increased. In the tumour drainage lymph nodes (TDLNs) of the combination group, there was a 18% reduction in CD8⁺IFN‐γ⁺ T cells and a 0.47% reduction in CD4⁺CD25⁺FOXP3⁺ regulatory T cells, as opposed to 5.0% and 5.1% reductions, respectively, for the control group. Superior suppression of CD11b⁺GR‐1⁺ myeloid‐derived suppressor cells (MDSCs) and the induction of M1 macrophages in the spleen and bone marrow of mice were found in the combination group. Abraxane and hIL15‐ABD effectively suppressed NF‐κB‐mediated immune suppressive markers, including indoleamine 2,3‐dioxygenase (IDO), Foxp3 and VEGF. In conclusion, Abraxane combined with hIL15‐ABD stimulates the anticancer activity of effector cells, inhibits immunosuppressive cells within the tumour microenvironment (TME) of PDAC, and produces a greater inhibitory effect than individual monotherapies.

Uncovering key targets of success for immunotherapy in pancreatic cancer

INTRODUCTION

Despite available treatment options, pancreatic ductal adenocarcinoma (PDAC) is frequently lethal. Recent immunotherapy strategies have failed to yield any notable impact. Therefore, research is focussed on unearthing new drug targets and therapeutic strategies to tackle this malignancy and attain more positive outcomes for patients.

AREAS COVERED

In this perspective article, we evaluate the main resistance mechanisms to immune checkpoint inhibitors (ICIs) and the approaches to circumvent them. We also offer an assessment of concluded and ongoing trials of PDAC immunotherapy. Literature research was performed on Pubmed accessible through keywords such as: 'pancreatic ductal adenocarcinoma,' 'immunotherapy,' 'immunotherapy resistance,' 'immune escape,' 'biomarkers.' Papers published between 2000 and 2021 were selected.

EXPERT OPINION

The tumor microenvironment is a critical variable of treatment resistance because of its role as a physical barrier and inhibitory immune signaling. Promising therapeutic strategies appear to be a combination of immunotherapeutics with other targeted treatments. Going forward, predictive biomarkers are required to improve patient selection. Biomarker-driven trials could enhance approaches for assessing the role of immunotherapy in PDAC.

Identification of tumour immune microenvironment-related alternative splicing events for the prognostication of pancreatic adenocarcinoma

PURPOSE

Pancreatic adenocarcinoma (PAAD) is characterized by low antitumour immune cell infiltration in an immunosuppressive microenvironment. This study aimed to systematically explore the impact on prognostic alternative splicing events (ASs) of tumour immune microenvironment (TIME) in PAAD.

METHODS

The ESTIMATE algorithm was implemented to compute the stromal/immune-related scores of each PAAD patient, followed by Kaplan-Meier (KM) survival analysis of patients with different scores grouped by X-tile software. TIME-related differentially expressed ASs (DEASs) were determined and evaluated through functional annotation analysis. In addition, Cox analyses were implemented to construct a TIME-related signature and an AS clinical nomogram. Moreover, comprehensive analyses, including gene set enrichment analysis (GSEA), immune infiltration, immune checkpoint gene expression, and tumour mutation were performed between the two risk groups to understand the potential mechanisms. Finally, Cytoscape was implemented to illuminate the AS-splicing factor (SF) regulatory network.

RESULTS

A total of 437 TIME-related DEASs significantly related to PAAD tumorigenesis and the formation of the TIME were identified. Additionally, a robust TIME-related prognostic signature based on seven DEASs was generated, and an AS clinical nomogram combining the signature and four clinical predictors also exhibited prominent discrimination by ROC (0.762 ~ 0.804) and calibration curves. More importantly, the fractions of CD8 T cells, regulatory T cells and activated memory CD4 T cells were lower, and the expression of four immune checkpoints-PD-L1, CD47, CD276, and PVR-was obviously higher in high-risk patients. Finally, functional analysis and tumour mutations revealed that aberrant immune signatures and activated carcinogenic pathways in high-risk patients may be the cause of the poor prognosis.

CONCLUSION

We extracted a list of DEASs associated with the TIME through the ESTIMATE algorithm and constructed a prognostic signature on the basis of seven DEASs to predict the prognosis of PAAD patients, which may guide advanced decision-making for personalized precision intervention.

Next-generation immunotherapy for pancreatic ductal adenocarcinoma: navigating pathways of immune resistance

To date, the use of immune checkpoint inhibitors has proven largely ineffective in patients with advanced pancreatic ductal adenocarcinoma. A combination of low tumor antigenicity, deficits in immune activation along with an exclusive and suppressive tumor microenvironment result in resistance to host defensives. However, a deepening understanding of these immune escape and suppressive mechanisms has led to the discovery of novel molecular targets and treatment strategies that may hold the key to a long-awaited therapeutic breakthrough. In this review, we describe the tumor-intrinsic and microenvironmental barriers to modern immunotherapy, examine novel immune-based and targeted modalities, summarize relevant pre-clinical findings and human experience, and, finally, discuss novel synergistic approaches to overcome immune-resistance in pancreatic cancer. Beyond checkpoint inhibition, immune agonists and anti-tumor vaccines represent promising strategies to stimulate host response via activation and expansion of anti-tumor immune effectors. Off-the-shelf natural killer cell therapies may offer an effective method for bypassing downregulated tumor antigen presentation. In parallel with this, sophisticated targeting of crosstalk between tumor and tumor-associated immune cells may lead to enhanced immune infiltration and survival of anti-tumor lymphocytes. A future multimodal treatment strategy involving immune priming/activation, tumor microenvironment reprogramming, and immune checkpoint blockade may help transform pancreatic cancer into an immunogenic tumor.

Natural Killer Cells and Dendritic Cells: Expanding Clinical Relevance in the Non-Small Cell Lung Cancer (NSCLC) Tumor Microenvironment

Non-small cell lung cancer (NSCLC) is a major subtype of lung cancer that accounts for almost 85% of lung cancer cases worldwide. Although recent advances in chemotherapy, radiotherapy, and immunotherapy have helped in the clinical management of these patients, the survival rate in advanced stages remains dismal. Furthermore, there is a critical lack of accurate prognostic and stratification markers for emerging immunotherapies. To harness immune response modalities for therapeutic benefits, a detailed understanding of the immune cells in the complex tumor microenvironment (TME) is required. Among the diverse immune cells, natural killer (NK cells) and dendritic cells (DCs) have generated tremendous interest in the scientific community. NK cells play a critical role in tumor immunosurveillance by directly killing malignant cells. DCs link innate and adaptive immune systems by cross-presenting the antigens to T cells. The presence of an immunosuppressive milieu in tumors can lead to inactivation and poor functioning of NK cells and DCs, which results in an adverse outcome for many cancer patients, including those with NSCLC. Recently, clinical intervention using modified NK cells and DCs have shown encouraging response in advanced NSCLC patients. Herein, we will discuss prognostic and predictive aspects of NK cells and DC cells with an emphasis on NSCLC. Additionally, the discussion will extend to potential strategies that seek to enhance the anti-tumor functionality of NK cells and DCs.