Heterogeneity and plasticity of cancer-associated fibroblasts in the pancreatic tumor microenvironment

The function of microRNA related to cancer-associated fibroblasts in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignant tumor characterized by a poor prognosis. A prominent feature of PDAC is the rich and dense stroma present in the tumor microenvironment (TME), which significantly hinders drug penetration. Cancer-associated fibroblasts (CAFs), activated fibroblasts originating from various cell sources, including pancreatic stellate cells (PSCs) and mesenchymal stem cells (MSCs), play a critical role in PDAC progression and TME formation. MicroRNAs (miRNAs) are small, single-stranded non-coding RNA molecules that are frequently involved in tumorigenesis and progression, exhibiting either oncolytic or oncogenic activity. Increasing evidence suggests that aberrant expression of miRNAs can mediate interactions between cancer cells and CAFs, thereby providing novel therapeutic targets for PDAC treatment. In this review, we will focus on the potential roles of miRNAs that target CAFs or CAFs-derived exosomes in PDAC progression, highlighting the feasibility of therapeutic strategies aimed at restoring aberrantly expressed miRNAs associated with CAFs, offering new pathways for the clinical management of PDAC.

Conserved spatial subtypes and cellular neighborhoods of cancer-associated fibroblasts revealed by single-cell spatial multi-omics

Cancer-associated fibroblasts (CAFs) are a multifaceted cell population essential for shaping the tumor microenvironment (TME) and influencing therapy responses. Characterizing the spatial organization and interactions of CAFs within complex tissue environments provides critical insights into tumor biology and immunobiology. In this study, through integrative analyses of over 14 million cells from 10 cancer types across 7 spatial transcriptomics and proteomics platforms, we discover, validate, and characterize four distinct spatial CAF subtypes. These subtypes are conserved across cancer types and independent of spatial omics platforms. Notably, they exhibit distinct spatial organizational patterns, neighboring cell compositions, interaction networks, and transcriptomic profiles. Their abundance and composition vary across tissues, shaping TME characteristics, such as levels, distribution, and state composition of tumor-infiltrating immune cells, tumor immune phenotypes, and patient survival. This study enriches our understanding of CAF spatial heterogeneity in cancer and paves the way for novel approaches to target and modulate CAFs.

An innovative strategy harnessing self-activating CAR-NK cells to mitigate TGF-β1-driven immune suppression

The dysfunction of natural killer (NK) cells, mediated by transforming growth factor β1 (TGFβ1) within the tumor microenvironment, impedes antitumor therapy and contributes to poor clinical outcomes. Our study introduces self-activating chimeric antigen receptor (CAR)-NK cells that block TGFβ1 signaling by releasing a specifically designed peptide, P6, which targets mesothelin in pancreatic tumors. P6 originates from the interaction sites between TGFβ1 and TGFβ receptor 1 and effectively disrupts TGFβ1's inhibitory signaling in NK cells. Our analysis demonstrates that P6 treatment interrupts the SMAD2/3 pathway in NK cells, mitigating TGFβ1-mediated suppression of NK cell activity, thereby enhancing their metabolic function and cytotoxic response against pancreatic tumors. These CAR-NK cells exhibit potent antitumor capabilities, as evidenced in spheroid cultures with cancer-associated fibroblasts and in vivo mouse models. Our approach marks a substantial advancement in overcoming TGFβ1-mediated immune evasion, offering a promising avenue for revolutionizing cancer immunotherapy.

Quantitative characterization of the 3D self-organization of PDAC tumor spheroids reveals cell type and matrix dependence through advanced microscopy analysis

Pancreatic ductal adenocarcinoma (PDAC) is characterized by an abundant tumor-associated stroma composed from pancreatic stellate cells, which play a critical role in tumor progression. Developing accurate in vitro models requires understanding the complex interactions between tumor cells and their microenvironment. In this study, we present a quantitative imaging-based characterization of the three dimensional (3D) self-organization of PDAC tumour spheroids using a microfluidic platform that mimics key aspects of the tumor microenvironment. Our model incorporates collagen type I hydrogels to recreate the extracellular matrix, activated human pancreatic stellate cells (HPSCs), and various tumor cell types. Advanced imaging techniques, including Lattice Lightsheet Microscopy, allowed us to analyze the 3D growth and spatial organization of the spheroids, revealing intricate biomechanical interactions. Our results indicate that alterations in matrix properties-such as stiffness, pore size, and hydraulic permeability-due to variations in collagen concentration significantly influence the growth patterns and organization of PDAC spheroids, depending on tumor subtype and epithelial-mesenchymal phenotype. Higher collagen concentrations promoted larger spheroids in epithelial-like cell lines, while mesenchymal-type cells required increased collagen for self-organization into smaller spheroids. Furthermore, coculture with HPSCs affected spheroid formation distinctly based on each PDAC cell line's genetic and phenotypic traits. HPSCs had opposing effects on epithelial-like cell lines: one cell line exhibited enhanced spheroid growth, while another showed inhibited formation, whereas mesenchymal-like spheroids showed minimal impact. These results provide insights into tumor-stroma interactions, emphasizing the importance of the cell-specific and matrix-dependent factors for advancing our understanding of PDAC progression and informing future therapeutic strategies.

Collagen remodeling-mediated signaling pathways and their impact on tumor therapy

In addition to their traditional roles in maintaining tissue morphology and organ development, emerging evidence suggests that collagen (COL) remodeling-referring to dynamic changes in the quantity, stiffness, arrangements, cleavage states, and homo-/hetero-trimerization of COLs-serves as a key signaling mechanism that governs tumor growth and metastasis. COL receptors act as switches, linking various forms of COL remodeling to different cell types during cancer progression, including cancer cells, immune cells, and cancer-associated fibroblasts. In this review, we summarize recent findings on the signaling pathways mediated by COL arrangement, cleavage, and trimerization states (both homo- and hetero-), as well as the roles of the primary COL receptors-integrin, DDR1/2, LAIR-1/2, MRC2, and GPVI-in cancer progression. We also discuss the latest therapeutic strategies targeting COL fragments, cancer-associated fibroblasts, and COL receptors, including integrins, DDR1/2, and LAIR1/2. Understanding the pathways modulated by COL remodeling and COL receptors in various pathological contexts will pave the way for developing new precision therapies.

KRT7 promotes pancreatic cancer metastasis by remodeling the extracellular matrix niche through FGF2-fibroblast crosstalk

Pancreatic ductal adenocarcinoma (PDAC) is a devastating cancer with a dismal prognosis due to distant metastasis. Through an analysis of large RNA sequencing and proteomics datasets, we found that high KRT7 expression in PDAC patients was correlated with liver metastasis and poor survival. A functional investigation revealed that the overexpression of KRT7 promoted liver metastasis but did not affect tumor cell proliferation in vivo or in vitro. Analysis of scRNA-Seq data from 24 PDAC samples revealed a negative correlation between KRT7 expression in PDAC cells and cancer-associated fibroblast (CAF) infiltration, and this was further confirmed in orthotopic tumor model mice injected with KRT7-overexpressing PDAC cells, which led the development of to a prometastatic niche with reduced ECM deposition. Mechanistically, KRT7 in PDAC cells promoted the secretion of FGF2, which inhibited CAF proliferation and ECM-related gene transcription through the Wnt/β-catenin pathway. Moreover, targeting FGF2 decreased liver metastasis in vivo. Our study revealed that KRT7 promotes PDAC liver metastasis by remodeling the extracellular matrix niche through FGF2-fibroblast crosstalk and provides a promising strategy for preventing PDAC liver metastasis.

Diagnostic Performance of Radiolabelled FAPI Versus [18F]FDG PET Imaging in Hepato-Pancreato-Biliary Oncology: A Systematic Review and Meta-Analysis

Radiolabelled fibroblast activation protein inhibitor (FAPI) tracers have the potential to overcome the limitations of 2-deoxy-2-[18F]fluoro-D-glucose ([18F]FDG) and improve the diagnosis and staging of hepato-pancreato-biliary (HPB) cancers. This study aims to compare the diagnostic performance of radiolabelled FAPI versus [18F]FDG PET imaging in HPB cancers. A systematic search of PubMed, Embase, Web of Science and Cochrane Library was performed to identify eligible studies on the diagnostic performance of FAPI PET for primary HPB tumours (hepatocellular carcinoma (HCC), pancreatic cancer (PC) and biliary tract cancer (BTC)) and for liver metastases of gastrointestinal origin. The diagnostic performance was defined as a combination of detection rate and semi-quantitative tracer uptake. A random-effects model was used to calculate the risk differences. In total, 28 studies were included. Histopathology was the reference standard for the primary tumour in 26 studies (93%). The detection rate of radiolabelled FAPI in comparison to [18F]FDG was significantly higher in HCC (0.33, 95% CI: 0.20-0.47 and 0.34, 95% CI: 0.23-0.45) and BTC (0.27, 95% CI: 0.11-0.43 and 0.28, 95% CI: 0.08-0.48), in the patient- and lesion-based analyses, respectively. In PC, no differences were observed. Radiolabelled FAPI outperformed [18F]FDG in the lesion-based detection of lymph node, liver and extra-hepatic metastases. In all HPB cancers, the mean SUVmax was significantly higher with radiolabelled FAPI compared to [18F]FDG. Molecular imaging with FAPI PET seems to have several benefits over [18F]FDG PET in HPB cancer diagnostics, with an overall higher tracer uptake, and higher detection rates in HCC and BTC.

Distinct response to IL-1β blockade in liver- and lung-specific metastasis mouse models of pancreatic cancer with heterogeneous tumor microenvironments

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a heterogeneous tumor microenvironment (TME). The mechanism by which this heterogeneity confers resistance against immunotherapy remains unclear. Interleukin- 1β (IL-1β) is a proinflammatory cytokine that regulates heterogeneous cancer associated fibroblast (CAF) phenotype and promotes an immunosuppressive TME. Anti-IL-1β monoclonal antibody significantly enhanced the anti-tumor activity of anti-PD-1 in a preclinical model of PDAC. However, clinical trials have shown limited activity of the anti-IL-1β and anti-PD-1 combination. Therefore, we hypothesize that anti-tumor immune response to the combination of anti-IL-1β and anti-PD-1 antibodies is context-dependent and would be affected by the TME heterogeneity in PDAC.

METHODS

Liver- and lung-specific metastasis mouse models of PDAC were used to investigate the antitumor activity of anti-IL-1β and anti-PD-1 antibodies alone or in combination by ultrasound examination and survival analysis. Their effects on the TME heterogeneity were assessed by flow cytometry and single nuclear RNA sequencing.

RESULTS

The combination of anti-IL-1β and anti-PD-1 antibodies does not slow primary tumor growth but prolongs overall survival and reduces lung metastasis rates in a PDAC orthotopic murine model with lung metastasis tropism. In contrast, combination therapy slows primary tumor growth and prolongs survival, but does not reduce liver metastasis rates in a PDAC murine orthotopic model with liver metastasis tropism. Flow cytometry analysis showed that the combination of anti-IL-1β and anti-PD-1 antibodies restores T cell activation negated by the monotherapies. Mechanistically, in the PDAC model with lung metastasis tropism, but not in the model with liver metastasis tropism, combination treatment reverses an increased trend of immunosuppressive myeloid cells as a result of monotherapy. Single-nuclear RNA sequencing analysis of both organ-specific tumor models demonstrated that anti-IL-1β treatment altered infiltration and function of CAF and immune cells differently. Furthermore, anti-IL-1β treatment modulated cytokine/chemokine ligand-receptor-receptor interactions in the models with different organ-specific metastasis distinctly.

CONCLUSION

This study reveals the differential responses of organ-specific metastasis mouse models of PDAC with distinct TMEs to anti-IL-1β and anti-PD-1 treatments, suggesting that treatment response is context-dependent and affected by TME heterogeneity.

Nanocarrier-mediated modulation of cGAS-STING signaling pathway to disrupt tumor microenvironment

The cGAS-STING signaling plays an important role in the immune response in a tumor microenvironment (TME) of triple-negative breast cancer (TNBC). The acute and controlled activation of cGAS-STING signaling results in tumor suppression, while chronic activation of cGAS-STING signaling results in immune-suppressive TME that could result in tumor survival. There is a need, therefore, to develop therapeutic strategies for harnessing tumor suppressive effects of cGAS-STING signaling while minimizing the risks associated with chronic activation. Combination therapies and nanocarriers-based delivery of cGAS-STING agonists have emerged as promising strategies in immunotherapy for controlled modulation of cGAS-STING signaling in cancer. These approaches aim to optimize the tumor suppressive effects of the cGAS-STING pathway while minimizing the challenges associated with modulators of cGAS-STING signaling. In the present review, we discuss recent advancements and strategies in combination therapies and nanocarrier-based delivery systems for effectively controlling cGAS-STING signaling in cancer immunotherapy. Further, we emphasized the significance of nanocarrier-based approaches for effective targeting of the cGAS-STING signaling, tackling resistance mechanisms, and overcoming key challenges like immune suppression, tumor heterogeneity, and off-target effects.

Organoids, tissue slices and organotypic cultures: Advancing our understanding of pancreatic ductal adenocarcinoma through in vitro and ex vivo models

Pancreatic ductal adenocarcinoma (PDAC) has one of the worst prognoses of all common solid cancers. For the large majority of PDAC patients, only systemic therapies with very limited efficacy are indicated. In addition, immunotherapies have not brought the advances seen in other cancer types. Several key characteristics of PDAC contribute to poor treatment outcomes, and in this review, we will discuss how these characteristics are best captured in currently available ex vivo or in vitro model systems. For instance, PDAC is hallmarked by a highly desmoplastic and immune-suppressed tumor microenvironment that impacts disease progression and therapy resistance. Also, large differences in tumor biology exist between and within tumors, complicating treatment decisions. Furthermore, PDAC has a very high propensity for locally invasive and metastatic growth. The use of animal models is often not desirable or feasible and several in vitro and ex vivo model systems have been developed, such as organotypic cocultures and tissue slices, among others. However, the absence of a full host organism impacts the ability of these models to accurately capture the characteristics that contribute to poor outcomes in PDAC. We will discuss the caveats and advantages of these model systems in the context of PDAC's key characteristics and provide recommendations on model choice and the possibilities for optimization. These considerations should be of use to researchers aiming to study PDAC in the in vitro setting.

Cell confinement by micropatterning induces phenotypic changes in cancer-associated fibroblasts

Recent advances in single-cell studies have revealed the vast transcriptomic heterogeneity of cancer-associated fibroblasts (CAFs), with each subset likely having unique roles in the tumor microenvironment. However, it is still unclear how different CAF subsets should be cultured in vitro to recapitulate their in vivo phenotype. The inherent plasticity of CAFs, or their ability to dynamically change their phenotype in response to different environmental stimuli, makes it highly challenging to induce and maintain a specific CAF state in vitro. In this study, we investigated how cell shape and confinement on two-dimensional culture substrates with different stiffnesses influence CAF transcriptomic profile and phenotype. Using micropatterning of polyacrylamide hydrogels to induce shape- and confinement-dependent changes in cell morphology, we observed that micropatterned CAFs exhibited phenotypic shifts towards more desmoplastic and inflammatory CAF subsets. Additionally, micropatterning enabled control over a range of CAF-specific markers and pathways. Lastly, we report how micropatterned and non-micropatterned CAFs respond differently to anti-cancer drugs, highlighting the importance of phenotype-oriented therapy that considers for CAF plasticity and regulatory networks. Control over CAF morphology offers a unique opportunity to establish highly robust CAF phenotypes in vitro, facilitating deeper understanding of CAF plasticity, heterogeneity, and development of novel therapeutic targets. STATEMENT OF SIGNIFICANCE: Cancer-associated fibroblasts (CAFs) are the dominant stromal cell type in many cancers, and recent studies have revealed that they are highly heterogeneous and comprise several subpopulations. It is still unclear how different subsets of CAFs should be cultured in vitro to recapitulate their in vivo phenotype. In this study, we investigated how cell shape and confinement affect CAF transcriptomic profile and phenotype. We report that micropatterned CAFs resemble desmoplastic and inflammatory CAF subsets observed in vivo and respond differently to anti-cancer drugs as compared to non-patterned CAFs. Control over CAF morphology enables the generation of highly robust CAF phenotypes in vitro, facilitating deeper understanding of CAF plasticity and heterogeneity.

Ex-Vivo 3D Cellular Models of Pancreatic Ductal Adenocarcinoma: From Embryonic Development to Precision Oncology

ABSTRACT

Pancreas is a vital gland of gastrointestinal system with exocrine and endocrine secretory functions, interweaved into essential metabolic circuitries of the human body. Pancreatic ductal adenocarcinoma (PDAC) represents one of the most lethal malignancies, with a 5-year survival rate of 11%. This poor prognosis is primarily attributed to the absence of early symptoms, rapid metastatic dissemination, and the limited efficacy of current therapeutic interventions. Despite recent advancements in understanding the etiopathogenesis and treatment of PDAC, there remains a pressing need for improved individualized models, identification of novel molecular targets, and development of unbiased predictors of disease progression. Here we aim to explore the concept of precision medicine utilizing 3-dimensional, patient-specific cellular models of pancreatic tumors and discuss their potential applications in uncovering novel druggable molecular targets and predicting clinical parameters for individual patients.

Dual rectification of metabolism abnormality in pancreatic cancer by a programmed nanomedicine

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive and lethal malignancy characterized by dysregulated energy and stromal metabolism. It is strongly supported by activated pancreatic stellate cells (PSC) which drive excessive desmoplasia and tumor growth via metabolic crosstalk. Herein, a programmed nanosystem is designed to dual rectify the metabolism abnormalities of the PDAC cells, which overexpress glucose transporter 1(GLUT1) and CD71, and the PSC for oncotherapy. The nanosystem is based on a tumor microenvironment-responsive liposome encapsulating an NF-κB inhibitor (TPCA-1) and a CD71 aptamer-linked Glut1 siRNA. TPCA-1 reverses the activated PSC to quiescence, which hampers metabolic support of the PSC to PDAC cells and bolsters the PDAC cell-targeting delivery of the siRNA. Aerobic glycolysis and the following enhancement of oxidative phosphorylation are restrained by the nano-modulation so as to amplify anti-PDAC efficacy in an orthotopic xenograft mouse model, which implies more personalized PDAC treatment based on different energy metabolic profiles.

Unveiling the resistance to therapies in pancreatic ductal adenocarcinoma

Despite the ongoing advances in interventional strategies (surgery, chemotherapy, radiotherapy, and immunotherapy) for managing pancreatic ductal adenocarcinoma (PDAC), the development of therapy refractory phenotypes remains a significant challenge. Resistance to various therapeutic modalities in PDAC emanates from a combination of inherent and acquired factors and is attributable to cancer cell-intrinsic and -extrinsic mechanisms. The critical determinants of therapy resistance include oncogenic signaling and epigenetic modifications that drive cancer cell stemness and metabolic adaptations, CAF-mediated stromagenesis that results in ECM deposition altered mechanotransduction, and secretome and immune evasion. We reviewed the current understanding of these multifaceted mechanisms operating in the PDAC microenvironment, influencing the response to chemotherapy, radiotherapy, and immunotherapy regimens. We then describe how the lessons learned from these studies can guide us to discover novel therapeutic regimens to prevent, delay, or revert resistance and achieve durable clinical responses.

Overcoming therapy resistance in pancreatic cancer: New insights and future directions

Pancreatic adenocarcinoma (PDAC) is predicted to become the second leading cause of cancer deaths by 2030 and this is mostly due to therapy failure. Limited treatment options and resistance to standard-of-care (SoC) therapies makes PDAC one of the cancer types with poorest prognosis and survival rates [1,2]. Pancreatic tumors are renowned for their poor response to therapeutic interventions including targeted therapies, chemotherapy and radiotherapy. Herein, we review hallmarks of therapy resistance in PDAC and current strategies aiming to tackle escape mechanisms and to re-sensitize cancer cells to therapy. We will further provide insights on recent advances in the field of drug discovery, nanomedicine, and disease models that are setting the ground for future research.

Resveratrol inhibits pancreatic cancer proliferation and metastasis by depleting senescent tumor-associated fibroblasts

BACKGROUND

Pancreatic cancer, a formidable gastrointestinal neoplasm, is characterized by its insidious onset, rapid progression, and resistance to treatment, which often lead to a grim prognosis. While the complex pathogenesis of pancreatic cancer is well recognized, recent attention has focused on the oncogenic roles of senescent tumor-associated fibroblasts. However, their precise role in pancreatic cancer remains unknown. Resveratrol is a natural polyphenol known for its multifaceted biological actions, including antioxidative and neuroprotective properties, as well as its potential to inhibit tumor proliferation and migration. Our current investigation builds on prior research and reveals the remarkable ability of resveratrol to inhibit pancreatic cancer proliferation and metastasis.

AIM

To explore the potential of resveratrol in inhibiting pancreatic cancer by targeting senescent tumor-associated fibroblasts.

METHODS

Immunofluorescence staining of pancreatic cancer tissues revealed prominent coexpression of α-SMA and p16. HP-1 expression was determined using immunohistochemistry. Cells were treated with the senescence-inducing factors known as 3CKs. Long-term growth assays confirmed that 3CKs significantly decreased the CAF growth rate. Western blotting was conducted to assess the expression levels of p16 and p21. Immunofluorescence was performed to assess LaminB1 expression. Quantitative real-time polymerase chain reaction was used to measure the levels of several senescence-associated secretory phenotype factors, including IL-4, IL-6, IL-8, IL-13, MMP-2, MMP-9, CXCL1, and CXCL12. A scratch assay was used to assess the migratory capacity of the cells, whereas Transwell assays were used to evaluate their invasive potential.

RESULTS

Specifically, we identified the presence of senescent tumor-associated fibroblasts within pancreatic cancer tissues, linking their abundance to cancer progression. Intriguingly, Resveratrol effectively eradicated these fibroblasts and hindered their senescence, which consequently impeded pancreatic cancer progression.

CONCLUSION

This groundbreaking discovery reinforces Resveratrol's stature as a potential antitumor agent and positions senescent tumor-associated fibroblasts as pivotal contenders in future therapeutic strategies against pancreatic cancer.

The role of microRNAs in the gastric cancer tumor microenvironment

BACKGROUND

Gastric cancer (GC) is one of the deadliest malignant tumors with unknown pathogenesis. Due to its treatment resistance, high recurrence rate, and lack of reliable early detection techniques, a majority of patients have a poor prognosis. Therefore, identifying new tumor biomarkers and therapeutic targets is essential. This review aims to provide fresh insights into enhancing the prognosis of patients with GC by summarizing the processes through which microRNAs (miRNAs) regulate the tumor microenvironment (TME) and highlighting their critical role in the TME.

MAIN TEXT

A comprehensive literature review was conducted by focusing on the interactions among tumor cells, extracellular matrix, blood vessels, cancer-associated fibroblasts, and immune cells within the GC TME. The role of noncoding RNAs, known as miRNAs, in modulating the TME through various signaling pathways, cytokines, growth factors, and exosomes was specifically examined. Tumor formation, metastasis, and therapy in GC are significantly influenced by interactions within the TME. miRNAs regulate tumor progression by modulating these interactions through multiple signaling pathways, cytokines, growth factors, and exosomes. Dysregulation of miRNAs affects critical cellular processes such as cell proliferation, differentiation, angiogenesis, metastasis, and treatment resistance, contributing to the pathogenesis of GC.

CONCLUSIONS

miRNAs play a crucial role in the regulation of the GC TME, influencing tumor progression and patient prognosis. By understanding the mechanisms through which miRNAs control the TME, potential biomarkers and therapeutic targets can be identified to improve the prognosis of patients with GC.

Enhancing Neoadjuvant Virotherapy's Effectiveness by Targeting Stroma to Improve Resectability in Pancreatic Cancer

About one-fourth of patients with pancreatic ductal adenocarcinoma (PDAC) are categorized as borderline resectable (BR) or locally advanced (LA). Chemotherapy and radiation therapy have not yielded the anticipated outcomes in curing patients with BR/LA PDAC. The surgical resection of these tumors presents challenges owing to the unpredictability of the resection margin, involvement of vasculature with the tumor, the likelihood of occult metastasis, a higher ratio of positive lymph nodes, and the relatively larger size of tumor nodules. Oncolytic virotherapy has shown promising activity in preclinical PDAC models. Unfortunately, the desmoplastic stroma within the PDAC tumor microenvironment establishes a barrier, hindering the infiltration of oncolytic viruses and various therapeutic drugs-such as antibodies, adoptive cell therapy agents, and chemotherapeutic agents-in reaching the tumor site. Recently, a growing emphasis has been placed on targeting major acellular components of tumor stroma, such as hyaluronic acid and collagen, to enhance drug penetration. Oncolytic viruses can be engineered to express proteolytic enzymes that cleave hyaluronic acid and collagen into smaller polypeptides, thereby softening the desmoplastic stroma, ultimately leading to increased viral distribution along with increased oncolysis and subsequent tumor size regression. This approach may offer new possibilities to improve the resectability of patients diagnosed with BR and LA PDAC.

The trend toward more target therapy in pancreatic ductal adenocarcinoma

INTRODUCTION

Despite the considerable progress made in cancer treatment through the development of target therapies, pancreatic ductal adenocarcinoma (PDAC) continues to exhibit resistance to this category of drugs. As a result, chemotherapy combination regimens remain the primary treatment approach for this aggressive cancer.

AREAS COVERED

In this review, we provide an in-depth analysis of past and ongoing trials on both well-known and novel targets that are being explored in PDAC, including PARP, EGFR, HER2, KRAS, and its downstream and upstream pathways (such as RAF/MEK/ERK and PI3K/AKT/mTOR), JAK/STAT pathway, angiogenesis, metabolisms, epigenetic targets, claudin, and novel targets (such as P53 and plectin). We also provide a comprehensive overview of the significant trials for each target, allowing a thorough glimpse into the past and future of target therapy.

EXPERT OPINION

The path toward implementing a target therapy capable of improving the overall survival of PDAC is still long, and it is unlikely that a monotherapy target drug will fulfill a meaningful role in addressing the complexity of this cancer. Thus, we discuss the future direction of target therapies in PDAC, trying to identify the more promising target and combination treatments, with a special focus on the more eagerly awaited ongoing trials.

Ubiquitin ligase TRIM15 promotes the progression of pancreatic cancer via the upregulation of the IGF2BP2-TLR4 axis

BACKGROUND

The tripartite motif family, predominantly characterized by its E3 ubiquitin ligase activities, is involved in various cellular processes including signal transduction, apoptosis and autophagy, protein quality control, immune regulation, and carcinogenesis. Tripartite Motif Containing 15 (TRIM15) plays an important role in melanoma progression through extracellular signal-regulated kinase activation; however, data on its role in pancreatic tumors remain lacking. We previously demonstrated that TRIM15 targeted lipid synthesis and metabolism in pancreatic cancer; however, other specific regulatory mechanisms remain elusive.

METHODS

We used transcriptomics and proteomics, conducted a series of phenotypic experiments, and used a mouse orthotopic transplantation model to study the specific mechanism of TRIM15 in pancreatic cancer in vitro and in vivo.

RESULTS

TRIM15 overexpression promoted the progression of pancreatic cancer by upregulating the toll-like receptor 4. The TRIM15 binding protein, IGF2BP2, could combine with TLR4 to inhibit its mRNA degradation. Furthermore, the ubiquitin level of IGF2BP2 was positively correlated with TRIM15.

CONCLUSIONS

TRIM15 could ubiquitinate IGF2BP2 to enhance the function of phase separation and the maintenance of mRNA stability of TLR4. TRIM15 is a potential therapeutic target against pancreatic cancer.

Polymeric nanofiber leveraged co-delivery of anti-stromal PAK1 inhibitor and paclitaxel enhances therapeutic effects in stroma-rich 3D spheroid models

The role of tumor stroma in solid tumors has been widely recognized in cancer progression, metastasis and chemoresistance. Cancer-associated fibroblasts (CAFs) play a crucial role in matrix remodeling and promoting cancer cell stemness and resistance via reciprocal crosstalk. Residual tumor tissue after surgical removal as well as unresectable tumors face therapeutic challenges to achieve curable outcome. In this study, we propose to develop a dual delivery approach by combining p21-activated kinase 1 (PAK1) inhibitor (FRAX597) to inhibit tumor stroma and chemotherapeutic agent paclitaxel (PTX) to kill cancer cells using electrospun nanofibers. First, the role of the PAK1 pathway was established in CAF differentiation, migration and contraction using relevant in vitro models. Second, polycaprolactone polymer-based nanofibers were fabricated using a uniaxial electrospinning technique to incorporate FRAX597 and/or PTX, which showed a uniform texture and a prolonged release of both drugs for 16 days. To test nanofibers, stroma-rich 3D heterospheroid models were set up which showed high resistance to PTX nanofibers compared to stroma-free homospheroids. Interestingly, nanofibers containing PTX and FRAX597 showed strong anti-tumor effects on heterospheroids by reducing the growth and viability by > 90 % compared to either of single drug-loaded nanofibers. These effects were reflected by reduced intra-spheroidal expression levels of collagen 1 and α-smooth muscle actin (α-SMA). Overall, this study provides a new therapeutic strategy to inhibit the tumor stroma using PAK1 inhibitor and thereby enhance the efficacy of chemotherapy using nanofibers as a local delivery system for unresectable or residual tumor. Use of 3D models to evaluate nanofibers highlights these models as advanced in vitro tools to study the effect of controlled release local drug delivery systems before animal studies.

Tumor Stroma as a Therapeutic Target for Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) has a poor prognosis owing to its desmoplastic stroma. Therefore, therapeutic strategies targeting this tumor stroma should be developed. In this study, we describe the heterogeneity of cancer-associated fibroblasts (CAFs) and their diverse roles in the progression, immune evasion, and resistance to treatment of PDAC. We subclassified the spatial distribution and functional activity of CAFs to highlight their effects on prognosis and drug delivery. Extracellular matrix components such as collagen and hyaluronan are described for their roles in tumor behavior and treatment outcomes, implying their potential as therapeutic targets. We also discussed the roles of extracellular matrix (ECM) including matrix metalloproteinases and tissue inhibitors in PDAC progression. Finally, we explored the role of the adaptive and innate immune systems in shaping the PDAC microenvironment and potential therapeutic strategies, with a focus on immune cell subsets, cytokines, and immunosuppressive mechanisms. These insights provide a comprehensive understanding of PDAC and pave the way for the development of prognostic markers and therapeutic interventions.

Discovery of YS-1 as a cell line of gastric inflammatory cancer-associated fibroblasts

BACKGROUND

Inflammatory cancer-associated fibroblasts (iCAFs) was first identified by co-culture of pancreatic stellate cells and tumor organoids. The key feature of iCAFs is IL-6high/αSMAlow. We examine this phenomenon in gastric cancer using two cell lines of gastric fibroblasts (HGF and YS-1).

METHODS AND RESULTS

HGF or YS-1 were co-cultured with MKN7 (a gastric adenocarcinoma cell line) in Matrigel. IL-6 protein levels in the culture supernatant were measured by ELISA. The increased production of IL-6 was not observed in any of the combinations. Instead, the supernatant of YS-1 exhibited the higher levels of IL-6. YS-1 showed IL-6high/αSMA (ACTA2)low in real-time PCR, mRNA-seq and immunohistochemistry. In mRNA-seq, iCAFs-associated genes and signaling pathways were up-regulated in YS-1. No transition to myofibroblastic phenotype was observed by monolayer culture, or the exposure to sonic hedgehog (SHH) or TGF-β. YS-1 conditioned medium induced changes of morphology and stem-ness/differentiation in NUGC-3 (a human gastric adenocarcinoma cell line) and UBE6T-15 (a human bone marrow-derived mesenchymal stem cell line).

CONCLUSIONS

YS-1 is a stable cell line of gastric iCAFs. This discovery will promote further research on iCAFs for many researchers.

Targeted Therapy for Highly Desmoplastic and Immunosuppressive Tumor Microenvironment of Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal malignancy with a very poor prognosis. Despite advancements in treatment strategies, PDAC remains recalcitrant to therapies because patients are often diagnosed at an advanced stage. The advanced stage of PDAC is characterized by metastasis, which typically renders it unresectable by surgery or untreatable by chemotherapy. The tumor microenvironment (TME) of PDAC comprises highly proliferative myofibroblast-like cells and hosts the intense deposition of a extracellular matrix component that forms dense fibrous connective tissue, a process called the desmoplastic reaction. In desmoplastic TMEs, the incessant aberration of signaling pathways contributes to immunosuppression by suppressing antitumor immunity. This feature offers a protective barrier that impedes the targeted delivery of drugs. In addition, the efficacy of immunotherapy is compromised because of the immune cold TME of PDAC. Targeted therapy approaches towards stromal and immunosuppressive TMEs are challenging. In this review, we discuss cellular and non-cellular TME components that contain actionable targets for drug development. We also highlight findings from preclinical studies and provide updates about the efficacies of new investigational drugs in clinical trials.

PDGFRα+ITGA11+ fibroblasts foster early-stage cancer lymphovascular invasion and lymphatic metastasis via ITGA11-SELE interplay

Cancer-associated fibroblasts (CAFs) exhibit considerable heterogeneity in advanced cancers; however, the functional annotation and mechanism of CAFs in early-stage cancers remain elusive. Utilizing single-cell RNA sequencing and spatial transcriptomic, we identify a previously unknown PDGFRα+ITGA11+ CAF subset in early-stage bladder cancer (BCa). Multicenter clinical analysis of a 910-case cohort confirms that PDGFRα+ITGA11+ CAFs are associated with lymphovascular invasion (LVI) and poor prognosis in early-stage BCa. These CAFs facilitate LVI and lymph node (LN) metastasis in early-stage BCa, as evidenced in a PDGFRα+ITGA11+ CAFs-specific deficient mouse model. Mechanistically, PDGFRα+ITGA11+ CAFs promote lymphangiogenesis via recognizing ITGA11 surface receptor SELE on lymphatic endothelial cells to activate SRC-p-VEGFR3-MAPK pathway. Further, CHI3L1 from PDGFRα+ITGA11+ CAFs aligns the surrounding matrix to assist cancer cell intravasation, fostering early-stage BCa LVI and LN metastasis. Collectively, our study reveals the crucial role of PDGFRα+ITGA11+ CAFs in shaping metastatic landscape, informing the treatment of early-stage BCa LVI.

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via exosomes in gastrointestinal tumors

Gastrointestinal (GI) tumors are a significant global health threat, with high rates of morbidity and mortality. Exosomes contain various biologically active molecules like nucleic acids, proteins, and lipids and can serve as messengers for intercellular communication. They play critical roles in the exchange of information between tumor cells and the tumor microenvironment (TME). The TME consists of mesenchymal cells and components of the extracellular matrix (ECM), with fibroblasts being the most abundant cell type in the tumor mesenchyme. Cancer-associated fibroblasts (CAFs) are derived from normal fibroblasts and mesenchymal stem cells that are activated in the TME. CAFs can secrete exosomes to modulate cell proliferation, invasion, migration, drug resistance, and other biological processes in tumors. Additionally, tumor cells can manipulate the function and behavior of fibroblasts through direct cell-cell interactions. This review provides a summary of the intercellular crosstalk between GI tumor cells and CAFs through exosomes, along with potential underlying mechanisms.

Emerging Therapeutic Options in Pancreatic Cancer Management

Pancreatic ductal adenocarcinoma (PDAC) is a devastating disease with a 5-year survival rate of <8% [...].

Translational and oncologic significance of tertiary lymphoid structures in pancreatic adenocarcinoma

Pancreatic adenocarcinoma (PDAC) is an aggressive tumor with poor survival and limited treatment options. PDAC resistance to immunotherapeutic strategies is multifactorial, but partially owed to an immunosuppressive tumor immune microenvironment (TiME). However, the PDAC TiME is heterogeneous and harbors favorable tumor-infiltrating lymphocyte (TIL) populations. Tertiary lymphoid structures (TLS) are organized aggregates of immune cells that develop within non-lymphoid tissue under chronic inflammation in multiple contexts, including cancers. Our current understanding of their role within the PDAC TiME remains limited; TLS are complex structures with multiple anatomic features such as location, density, and maturity that may impact clinical outcomes such as survival and therapy response in PDAC. Similarly, our understanding of methods to manipulate TLS is an actively developing field of research. TLS may function as anti-tumoral immune niches that can be leveraged as a therapeutic strategy to potentiate both existing chemotherapeutic regimens and potentiate future immune-based therapeutic strategies to improve patient outcomes. This review seeks to cover anatomy, relevant features, immune effects, translational significance, and future directions of understanding TLS within the context of PDAC.

Evidence of steady-state fibroblast subtypes in the normal human breast as cells-of-origin for perturbed-state fibroblasts in breast cancer

BACKGROUND

Human breast cancer most frequently originates within a well-defined anatomical structure referred to as the terminal duct lobular unit (TDLU). This structure is endowed with its very own lobular fibroblasts representing one out of two steady-state fibroblast subtypes-the other being interlobular fibroblasts. While cancer-associated fibroblasts (CAFs) are increasingly appreciated as covering a spectrum of perturbed states, we lack a coherent understanding of their relationship-if any-with the steady-state fibroblast subtypes. To address this, we here established two autologous CAF lines representing inflammatory CAFs (iCAFs) and myofibroblast CAFs (myCAFs) and compared them with already established interlobular- and lobular fibroblasts with respect to their origin and impact on tumor formation.

METHODS

Primary breast tumor-derived CAFs were transduced to express human telomerase reverse transcriptase (hTERT) and sorted into CD105low and CD105high populations using fluorescence-activated cell sorting (FACS). The two populations were tested for differentiation similarities to iCAF and myCAF states through transcriptome-wide RNA-Sequencing (RNA-Seq) including comparison to an available iCAF-myCAF cell state atlas. Inference of origin in interlobular and lobular fibroblasts relied on RNA-Seq profiles, immunocytochemistry and growth characteristics. Osteogenic differentiation and bone formation assays in culture and in vivo were employed to gauge for origin in bone marrow-derived mesenchymal stem cells (bMSCs). Functional characteristics were assessed with respect to contractility in culture and interaction with tumor cells in mouse xenografts. The cells' gene expression signatures were tested for association with clinical outcome of breast cancer patients using survival data from The Cancer Genome Atlas database.

RESULTS

We demonstrate that iCAFs have properties in common with interlobular fibroblasts while myCAFs and lobular fibroblasts are related. None of the CAFs qualify as bMSCs as revealed by lack of critical performance in bone formation assays. Functionally, myCAFs and lobular fibroblasts are almost equally tumor promoting as opposed to iCAFs and interlobular fibroblasts. A myCAF gene signature is found to associate with poor breast cancer-specific survival.

CONCLUSIONS

We propose that iCAFs and myCAFs originate in interlobular and lobular fibroblasts, respectively, and more importantly, that the tumor-promoting properties of lobular fibroblasts render the TDLU an epicenter for breast cancer evolution.

Cancer-associated fibroblasts drive early pancreatic cancer cell invasion via the SOX4/MMP11 signalling axis

Pancreatic ductal adenocarcinoma (PDAC) is characterized by abundant cancer-associated fibroblasts (CAFs), early perineural invasion (PNI) and microvascular invasion (MVI). However, the differentiation trajectories and underlying molecular mechanisms of CAFs in PDAC early invasion have not been fully elucidated. In this study, we integrated and reanalysed single-cell data from the National Geoscience Data Centre (NGDC) database and confirmed that myofibroblast-like CAFs (myCAFs) mediated epithelial-mesenchymal transformation (EMT) and enhanced the invasion abilities of PDAC cells by secreting regulators of angiogenesis and metastasis. Furthermore, we constructed a differentiation trajectory of CAFs and revealed that reprogramming from iCAFs to myCAFs was associated with poor prognosis. Mechanistically, SOX4 was aberrantly activated in myCAFs, which promoted the secretion of MMP11 and eventually induced early cancer cell invasion. Together, our results provide a comprehensive transcriptomic overview of PDAC patients with early invasion and reveal the intercellular crosstalk between myCAFs and cancer cells, which suggests potential targets for early invasion PDAC therapy.

Thinking small to win big? A critical review on the potential application of extracellular vesicles for biomarker discovery and new therapeutic approaches in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is an extremely deadly form of cancer, with limited progress in 5-year survival rates despite significant research efforts. The main challenges in treating PDAC include difficulties in early detection, and resistance to current therapeutic approaches due to aggressive molecular and microenvironment features. These challenges emphasize the importance of identifying clinically validated biomarkers for early detection and clinical management. Extracellular vesicles (EVs), particularly exosomes, have emerged as crucial mediators of intercellular communication by transporting molecular cargo. Recent research has unveiled their role in initiation, metastasis, and chemoresistance of PDAC. Consequently, utilizing EVs in liquid biopsies holds promise for the identification of biomarkers for early detection, prognosis, and monitoring of drug efficacy. However, numerous limitations, including challenges in isolation and characterization of homogeneous EVs populations, as well as the absence of standardized protocols, can affect the reliability of studies involving EVs as biomarkers, underscoring the necessity for a prudent approach. EVs have also garnered considerable attention as a promising drug delivery system and novel therapy for tumors. The loading of biomolecules or chemical drugs into exosomes and their subsequent delivery to target cells can effectively impede tumor progression. Nevertheless, there are obstacles that must be overcome to ensure the accuracy and efficacy of therapies relying on EVs for the treatment of tumors. In this review, we examine both recent advancements and remaining obstacles, exploring the potential of utilizing EVs in biomarker discovery as well as for the development of drug delivery vehicles.

Hydrogel-Based Therapeutics for Pancreatic Ductal Adenocarcinoma Treatment

Pancreatic ductal adenocarcinoma (PDAC), one of the deadliest malignancies worldwide, is characteristic of the tumor microenvironments (TME) comprising numerous fibroblasts and immunosuppressive cells. Conventional therapies for PDAC are often restricted by limited drug delivery efficiency, immunosuppressive TME, and adverse effects. Thus, effective and safe therapeutics are urgently required for PDAC treatment. In recent years, hydrogels, with their excellent biocompatibility, high drug load capacity, and sustainable release profiles, have been developed as effective drug-delivery systems, offering potential therapeutic options for PDAC. This review summarizes the distinctive features of the immunosuppressive TME of PDAC and discusses the application of hydrogel-based therapies in PDAC, with a focus on how these hydrogels remodel the TME and deliver different types of cargoes in a controlled manner. Furthermore, we also discuss potential drug candidates and the challenges and prospects for hydrogel-based therapeutics for PDAC. By providing a comprehensive overview of hydrogel-based therapeutics for PDAC treatment, this review seeks to serve as a reference for researchers and clinicians involved in developing therapeutic strategies targeting the PDAC microenvironment.

Development and validation of a radiomics model of magnetic resonance for predicting liver metastasis in resectable pancreatic ductal adenocarcinoma patients

BACKGROUND

Nearly one fourth of patients with pancreatic ductal adenocarcinoma (PDAC) occur to liver metastasis after surgery, and liver metastasis is a risk factor for prognosis for those patients with surgery therapy. However, there is no effective way to predict liver metastasis post-operation.

METHOD

Clinical data and preoperative magnetic resonance imaging (MRI) of PDAC patients diagnosed between July 2010 and July 2020 were retrospectively collected from three hospital centers in China. The significant MRI radiomics features or clinicopathological characteristics were used to establish a model to predict liver metastasis in the development and validation cohort.

RESULTS

A total of 204 PDAC patients from three hospital centers were divided randomly (7:3) into development and validation cohort. Due to poor predictive value of clinical features, MRI radiomics model had similar receiver operating characteristics curve (ROC) value to clinical-radiomics combing model in development cohort (0.878 vs. 0.880, p = 0.897) but better ROC in validation dataset (0.815 vs. 0.732, p = 0.022). Radiomics model got a sensitivity of 0.872/0.750 and a specificity of 0.760/0.822 to predict liver metastasis in development and validation cohort, respectively. Among 54 patients randomly selected with post-operation specimens, fibrosis markers (α-smooth muscle actin) staining was shown to promote radiomics model with ROC value from 0.772 to 0.923 (p = 0.049) to predict liver metastasis.

CONCLUSION

This study developed and validated an MRI-based radiomics model and showed a good performance in predicting liver metastasis in resectable PDAC patients.

A Quick Guide to CAF Subtypes in Pancreatic Cancer

Pancreatic cancer represents one of the most desmoplastic malignancies and is characterized by an extensive deposition of extracellular matrix. The latter is provided by activated cancer-associated fibroblasts (CAFs), which are abundant cells in the pancreatic tumor microenvironment. Many recent studies have made it clear that CAFs are not a singular cellular entity but represent a multitude of potentially dynamic subgroups that affect tumor biology at several levels. As mentioned before, CAFs significantly contribute to the fibrotic reaction and the biomechanical properties of the tumor, but they can also modulate the local immune environment and the response to targeted, chemo or radiotherapy. As the number of known and emerging CAF subgroups is steadily increasing, it is becoming increasingly difficult to keep up with these developments and to clearly discriminate the cellular subsets identified so far. This review aims to provide a helpful overview that enables readers to quickly familiarize themselves with field of CAF heterogeneity and to grasp the phenotypic, functional and therapeutic distinctions of the various stromal subpopulations.

Fibroblasts in pancreatic cancer: molecular and clinical perspectives

Pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs) are highly abundant cells in the pancreatic tumor microenvironment (TME) that modulate desmoplasia. The formation of a dense stroma leads to immunosuppression and therapy resistance that are major causes of treatment failure in pancreatic ductal adenocarcinoma (PDAC). Recent evidence suggests that several subpopulations of CAFs in the TME can interconvert, explaining the dual roles (antitumorigenic and protumorigenic) of CAFs in PDAC and the contradictory results of CAF-targeted therapies in clinical trials. This highlights the need to clarify CAF heterogeneity and their interactions with PDAC cells. This review focuses on the communication between activated PSCs/CAFs and PDAC cells, as well as on the mechanisms underlying this crosstalk. CAF-focused therapies and emerging biomarkers are also outlined.

Drug Delivery Strategies for the Treatment of Pancreatic Cancer

Pancreatic cancer is fast becoming a global menace and it is projected to be the second leading cause of cancer-related death by 2030. Pancreatic adenocarcinomas, which develop in the pancreas' exocrine region, are the predominant type of pancreatic cancer, representing about 95% of total pancreatic tumors. The malignancy progresses asymptomatically, making early diagnosis difficult. It is characterized by excessive production of fibrotic stroma known as desmoplasia, which aids tumor growth and metastatic spread by remodeling the extracellular matrix and releasing tumor growth factors. For decades, immense efforts have been harnessed toward developing more effective drug delivery systems for pancreatic cancer treatment leveraging nanotechnology, immunotherapy, drug conjugates, and combinations of these approaches. However, despite the reported preclinical success of these approaches, no substantial progress has been made clinically and the prognosis for pancreatic cancer is worsening. This review provides insights into challenges associated with the delivery of therapeutics for pancreatic cancer treatment and discusses drug delivery strategies to minimize adverse effects associated with current chemotherapy options and to improve the efficiency of drug treatment.

GLI1 interaction with p300 modulates SDF1 expression in cancer-associated fibroblasts to promote pancreatic cancer cells migration

Carcinoma-associated fibroblasts (CAFs) play an important role in the progression of multiple malignancies. Secretion of cytokines and growth factors underlies the pro-tumoral effect of CAFs. Although this paracrine function has been extensively documented, the molecular mechanisms controlling the expression of these factors remain elusive. In this study, we provide evidence of a novel CAF transcriptional axis regulating the expression of SDF1, a major driver of cancer cell migration, involving the transcription factor GLI1 and histone acetyltransferase p300. We demonstrate that conditioned media from CAFs overexpressing GLI1 induce the migration of pancreatic cancer cells, and this effect is impaired by an SDF1-neutralizing antibody. Using a combination of co-immunoprecipitation, proximity ligation assay and chromatin immunoprecipitation assay, we further demonstrate that GLI1 and p300 physically interact in CAFs to co-occupy and drive SDF1 promoter activity. Mapping experiments highlight the requirement of GLI1 N-terminal for the interaction with p300. Importantly, knockdowns of both GLI1 and p300 reduce SDF1 expression. Further analysis shows that knockdown of GLI1 decreases SDF1 promoter activity, p300 recruitment, and levels of its associated histone marks (H4ac, H3K27ac, and H3K14ac). Finally, we show that the integrity of two GLI binding sites in the SDF1 promoter is required for p300 recruitment. Our findings define a new role for the p300-GLI1 complex in the regulation of SDF1, providing new mechanistic insight into the molecular events controlling pancreatic cancer cells migration.

Synergistic therapeutic combination with a CAF inhibitor enhances CAR-NK-mediated cytotoxicity via reduction of CAF-released IL-6

BACKGROUND

Cancer-associated fibroblasts (CAFs) in the tumor microenvironment (TME) contribute to an impaired functionality of natural killer (NK) cells that have emerged as a promising therapeutic modality. The interaction between CAFs and NK cells within the TME exerts major inhibitory effects on immune responses, indicating CAF-targeted therapies as potential targets for effective NK-mediated cancer killing.

METHODS

To overcome CAF-induced NK dysfunction, we selected an antifibrotic drug, nintedanib, for synergistic therapeutic combination. To evaluate synergistic therapeutic efficacy, we established an in vitro 3D Capan2/patient-derived CAF spheroid model or in vivo mixed Capan2/CAF tumor xenograft model. The molecular mechanism of NK-mediated synergistic therapeutic combination with nintedanib was revealed through in vitro experiments. In vivo therapeutic combination efficacy was subsequently evaluated. Additionally, the expression score of target proteins was measured in patient-derived tumor sections by the immunohistochemical method.

RESULTS

Nintedanib blocked the platelet-derived growth factor receptor β (PDGFRβ) signaling pathway and diminished the activation and growth of CAFs, markedly reducing CAF-secreted IL-6. Moreover, coadministration of nintedanib improved the mesothelin (MSLN) targeting chimeric antigen receptor-NK-mediated tumor killing abilities in CAF/tumor spheroids or a xenograft model. The synergistic combination resulted in intense NK infiltration in vivo. Nintedanib alone exerted no effects, whereas blockade of IL-6 trans-signaling ameliorated the function of NK cells. The combination of the expression of MSLN and the PDGFRβ+-CAF population area, a potential prognostic/therapeutic marker, was associated with inferior clinical outcomes.

CONCLUSION

Our strategy against PDGFRβ+-CAF-containing pancreatic cancer allows improvements in the therapy of pancreatic ductal adenocarcinoma.

Therapeutic Strategies to Overcome Fibrotic Barriers to Nanomedicine in the Pancreatic Tumor Microenvironment

Pancreatic cancer is notorious for its dismal prognosis. The enhanced permeability and retention (EPR) effect theory posits that nanomedicines (therapeutics in the size range of approximately 10-200 nm) selectively accumulate in tumors. Nanomedicine has thus been suggested to be the "magic bullet"-both effective and safe-to treat pancreatic cancer. However, the densely fibrotic tumor microenvironment of pancreatic cancer impedes nanomedicine delivery. The EPR effect is thus insufficient to achieve a significant therapeutic effect. Intratumoral fibrosis is chiefly driven by aberrantly activated fibroblasts and the extracellular matrix (ECM) components secreted. Fibroblast and ECM abnormalities offer various potential targets for therapeutic intervention. In this review, we detail the diverse strategies being tested to overcome the fibrotic barriers to nanomedicine in pancreatic cancer. Strategies that target the fibrotic tissue/process are discussed first, which are followed by strategies to optimize nanomedicine design. We provide an overview of how a deeper understanding, increasingly at single-cell resolution, of fibroblast biology is revealing the complex role of the fibrotic stroma in pancreatic cancer pathogenesis and consider the therapeutic implications. Finally, we discuss critical gaps in our understanding and how we might better formulate strategies to successfully overcome the fibrotic barriers in pancreatic cancer.

Diagnostic accuracy and added value of blood-based protein biomarkers for pancreatic cancer: A meta-analysis of aggregate and individual participant data

BACKGROUND

Novel blood-based protein biomarkers may be of value for efficient, accurate, and non-invasive diagnosis of pancreatic cancer. This study assesses the diagnostic accuracy of newly recognized blood-based protein biomarkers for detecting pancreatic cancer, and investigates their added value to CA19-9, the common blood-based biomarker in clinical use for pancreatic cancer.

METHODS

PubMed, Embase, Web of Science, and the Wiley/Cochrane Library were systematically searched from inception until June 2022. A meta-analysis of aggregate and individual participant data was conducted using frequentist and Bayesian hierarchical random-effects models. The added clinical utility of protein biomarkers was investigated using bootstrap bias-corrected decision curve analyses.

FINDINGS

Aggregate data from 28 primary studies (6127 participants) were included, of which 8 studies (1790 participants) provided individual participant data. CA19-9 was significantly more accurate than MIC-1 for distinguishing pancreatic cancer from benign disease (AUC, 0.83 vs 0.74; relative diagnostic odds ratio [rDOR], 2.10 [95% CI, 0.98-4.48]; p = 0.002), THBS2 (AUC, 0.87 vs 0.69; rDOR, 4.53 [2.16-9.39]; p < 0.0001), TIMP-1 (AUC, 0.91 vs 0.70; rDOR, 8.00 [3.81-16.9]; p < 0.0001), OPN (AUC, 0.89 vs 0.74; rDOR, 4.22 [1.13-15.6]; p < 0.0001), ICAM-1 (AUC, 0.91 vs 0.68; rDOR 9.30 [0.87-99.5]; p < 0.0001), and IGFBP2 (AUC, 0.91 vs 0.68; rDOR, 4.48 [0.78-24.3]; p < 0.0001). The addition of these novel protein biomarkers to CA19-9 did not significantly improve the AUC, and resulted in minor increases or limited decreases in clinical utility.

INTERPRETATION

Novel protein biomarkers have moderate diagnostic accuracy, do not outperform CA19-9 in differentiating pancreatic cancer from benign disease, and show limited added clinical value to CA19-9. We propose recommendations to aid the development of minimally invasive diagnostic tests with sufficient clinical utility to improve the management of patients with suspected pancreatic cancer.

FUNDING

Bennink Foundation, Dutch Cancer Foundation (KWF Kankerbestrijding), and AIRC.

Exosome-derived FGD5-AS1 promotes tumor-associated macrophage M2 polarization-mediated pancreatic cancer cell proliferation and metastasis

Inflammatory molecules and exosomes are crucial for signal transduction between tumor-associated macrophages and tumor cells. IL-6, a key inflammatory molecule secreted by M2 macrophages after polarization, can mediate malignant progression of pancreatic cancer (PC). However, the functions and mechanisms of IL-6 and tumor-derived exosomes in tumor-associated macrophages and PC remain unclear. Transcriptome chip and quantitative reverse transcription PCR experiments indicated that FGD5-AS1 induced IL-6 and high FGD5-AS1 expression correlated with the poor prognosis in PC patients. RNA pulldown, mass spectrometry, and dual luciferase reporter assays were used to identify the mechanism of exosomal FGD5-AS1 in promoting PC progression and M2 macrophage polarization. FGD5-AS1 exerted cancer-promoting functions when co-cultured with M2 macrophages. PC-derived exosomal FGD5-AS1 stimulated M2 macrophage polarization by activating STAT3/NF-κB pathway. FGD5-AS1 interacts with p300, resulting in STAT3 acetylation, thus promoting nuclear localization and transcriptional activity of STAT3/NF-κB. These data indicated that PC cells generate FGD5-AS1-rich exosomes, which cause M2 macrophage polarization to promote the malignant behaviors of PC cells. Targeting exosomal FGD5-AS1 may provide a potential diagnosis and treatment strategy for PC.

Fibroblast heterogeneity in solid tumors: From single cell analysis to whole-body imaging

Cancer-Associated Fibroblasts (CAFs) represent the most prominent component of the tumor microenvironment (TME). Recent studies demonstrated that CAF are heterogeneous and composed of different subpopulations exerting distinct functions in cancer. CAF populations differentially modulate various aspects of tumor growth, including cancer cell proliferation, extra-cellular matrix remodeling, metastatic dissemination, immunosuppression and resistance to treatment. Among other markers, the Fibroblast Activation Protein (FAP) led to the identification of a specific CAF subpopulation involved in metastatic spread and immunosuppression. Expression of FAP at the surface of CAF is detected in many different cancer types of poor prognosis. Thus, FAP recently appears as an appealing target for therapeutic and molecular imaging applications. In that context, ⁶⁸Ga-labeled radiopharmaceutical-FAP-inhibitors (FAPI) have been recently developed and validated for quantitatively mapping FAP expression over the whole-body using Positron Emission Tomography (PET/CT). In this review, we describe the main current knowledge on CAF subpopulations and their distinct functions in solid tumors, as well as the promising diagnostic and therapeutic implications of radionuclides targeting FAP.

Cancer-associated fibroblasts in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a lethal cancer with a prominent extracellular matrix (ECM) deposition and poor prognosis. High levels of ECM proteins derived from tumour cells reduce the efficacy of conventional cancer treatment paradigms and contribute to tumour progression and metastasis. As abundant tumour-promoting cells in the ECM, cancer-associated fibroblasts (CAFs) are promising targets for novel anti-tumour interventions. Nonetheless, related clinical trials are hampered by the lack of specific markers and elusive differences between CAF subtypes. Here, we review the origins and functional diversity of CAFs and show how they create a tumour-promoting milieu, focusing on the crosstalk between CAFs, tumour cells, and immune cells in the tumour microenvironment. Furthermore, relevant clinical advances and potential therapeutic strategies relating to CAFs are discussed.

Pancreatic Ductal Adenocarcinoma: Molecular Pathology and Predictive Biomarkers

Pancreatic ductal adenocarcinoma (PDAC) has an extremely poor prognosis due to the lack of methods or biomarkers for early diagnosis and its resistance to conventional treatment modalities, targeted therapies, and immunotherapies. PDACs are a heterogenous group of malignant epithelial neoplasms with various histomorphological patterns and complex, heterogenous genetic/molecular landscapes. The newly proposed molecular classifications of PDAC based on extensive genomic, transcriptomic, proteomic and epigenetic data have provided significant insights into the molecular heterogeneity and aggressive biology of this deadly disease. Recent studies characterizing the tumor microenvironment (TME) have shed light on the dynamic interplays between the tumor cells and the immunosuppressive TME of PDAC, which is essential to disease progression, as well as its resistance to chemotherapy, newly developed targeted therapy and immunotherapy. There is a critical need for the development of predictive markers that can be clinically utilized to select effective personalized therapies for PDAC patients. In this review, we provide an overview of the histological and molecular heterogeneity and subtypes of PDAC, as well as its precursor lesions, immunosuppressive TME, and currently available predictive molecular markers for patients.

Role of drug catabolism, modulation of oncogenic signaling and tumor microenvironment in microbe-mediated pancreatic cancer chemoresistance

Pancreatic ductal adenocarcinoma (PDAC) has one of the highest incidence/death ratios among all neoplasms due to its late diagnosis and dominant chemoresistance. Most PDAC patients present with an advanced disease characterized by a multifactorial, inherent and acquired resistance to current anticancer treatments. This remarkable chemoresistance has been ascribed to several PDAC features including the genetic landscape, metabolic alterations, and a heterogeneous tumor microenvironment that is characterized by dense fibrosis, and a cellular contexture including functionally distinct subclasses of cancer-associated fibroblasts, immune suppressive cells, but also a number of bacteria, shaping a specific tumor microbiome microenvironment. Thus, recent studies prompted the emergence of a new research avenue, by describing the role of the microbiome in gemcitabine resistance, while next-generation-sequencing analyses identified a specific microbiome in different tumors, including PDAC. Functionally, the contribution of these microbes to PDAC chemoresistance is only beginning to be explored. Here we provide an overview of the studies demonstrating that bacteria have the capacity to metabolically transform and hence inactivate anticancer drugs, as exemplified by the inhibition of the efficacy of 10 out of 30 chemotherapeutics by Escherichia coli. Moreover, a number of bacteria modulate specific oncogenic pathways, such as Fusobacterium nucleatum, affecting autophagy and apoptosis induction by 5-fluorouracil and oxaliplatin. We hypothesize that improved understanding of how chemoresistance is driven by bacteria could enhance the efficacy of current treatments, and discuss the potential of microbiome modulation and targeted therapeutic approaches as well as the need for more reliable models and biomarkers to translate the findings of preclinical/translational research to the clinical setting, and ultimately overcome PDAC chemoresistance, hence improving clinical outcome.

Senescent Human Pancreatic Stellate Cells Secrete CXCR2 Agonist CXCLs to Promote Proliferation and Migration of Human Pancreatic Cancer AsPC-1 and MIAPaCa-2 Cell Lines

Interactions between pancreatic cancer cells and pancreatic stellate cells (PSCs) play an important role in the progression of pancreatic cancer. Recent studies have shown that cellular senescence and senescence-associated secretory phenotype factors play roles in the progression of cancer. This study aimed to clarify the effects of senescence-induced PSCs on pancreatic cancer cells. Senescence was induced in primary-cultured human PSCs (hPSCs) through treatment with hydrogen peroxide or gemcitabine. Microarray and Gene Ontology analyses showed the alterations in genes and pathways related to cellular senescence and senescence-associated secretory phenotype factors, including the upregulation of C-X-C motif chemokine ligand (CXCL)-1, CXCL2, and CXCL3 through the induction of senescence in hPSCs. Conditioned media of senescent hPSCs increased the proliferation—as found in an assessment with a BrdU incorporation assay—and migration—as found in an assessment with wound-healing and two-chamber assays—of pancreatic cancer AsPC-1 and MIAPaca-2 cell lines. SB225002, a selective CXCR2 antagonist, and SCH-527123, a CXCR1/CXCR2 antagonist, attenuated the effects of conditioned media of senescent hPSCs on the proliferation and migration of pancreatic cancer cells. These results suggest a role of CXCLs as senescence-associated secretory phenotype factors in the interaction between senescent hPSCs and pancreatic cancer cells. Senescent PSCs might be novel therapeutic targets for pancreatic cancer.

It Takes Two to Tango: Potential Prognostic Impact of Circulating TGF-Beta and PD-L1 in Pancreatic Cancer

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly devastating disease with rising incidence and poor prognosis. The lack of reliable prognostic biomarkers hampers the individual evaluation of the survival and recurrence potential. Methods: Here, we investigate the value of plasma levels of two potential key players in molecular mechanisms underlying PDAC aggressiveness and immune evasion, soluble TGF-beta (sTGF-beta) and sPD-L1, in both metastatic and radically-resected PDAC. To this aim we prospectively enrolled 38 PDAC patients and performed appropriate statistical analyses in order to evaluate their correlation, and role in the prediction of disease relapse/progression, and patients’ outcome. Results: Metastatic patients showed lower levels of circulating sTGF-beta and higher levels of sPD-L1 compared to radically-resected patients. Moreover, a decrease in sTGF-beta levels (but not sPD-L1) was significantly associated with disease relapse in radically-resected patients. We also observed lower sTGF-beta at disease progression after first-line chemotherapy in metastatic patients, though this change was not statistically significant. We found a significant correlation between the levels of sTGF-beta and sPD-L1 before first-line chemotherapy. Conclusions: These findings support the possible interaction of TGF-beta and PD-L1 pathways and suggest that sTGF-beta and sPD-L1 might synergize and be new potential blood-based biomarkers.

AdipoRon and Pancreatic Ductal Adenocarcinoma: a future perspective in overcoming chemotherapy-induced resistance?

The latest scientific knowledge has provided additional insights accountable for the worst prognosis for pancreatic ductal adenocarcinoma (PDAC). Among the causative factors, the aptitude to develop resistance towards approved medications denotes the master key for understanding the lack of improvement in PDAC survival over the years. Even though several compounds have achieved encouraging results at preclinical stage, no new adjuvant agents have reached the bedside of PDAC patients lately. The adiponectin receptor agonist AdipoRon is emerging as a promising anticancer drug in different cancer models, particularly in PDAC. Building on the existing findings, we recently reinforced its candidacy in PDAC cells, proposing AdipoRon either as a suitable partner in gemcitabine-based treatment or as an effective drug in resistant cells. Crossing the current state-of-the-art, herein we provide a critical perspective on AdipoRon to figure out whether this receptor agonist can potentially be considered a future therapeutic choice in overcoming chemotherapy-induced resistance, expressly in PDAC.

Biodegradable Ultrasmall-in-Nano Architectures Loaded with Cisplatin Prodrug in Combination with Ionizing Radiation Induces DNA Damage and Apoptosis in Pancreatic Ductal Adenocarcinoma

Considering the dismal survival rate, novel therapeutic strategies are warranted to improve the outcome of pancreatic ductal adenocarcinoma (PDAC). Combining nanotechnology for delivery of chemotherapeutics-preferably radiosensitizing agents-is a promising approach to enhance the therapeutic efficacy of chemoradiation. We assessed the effect of biodegradable ultrasmall-in-nano architectures (NAs) containing gold ultra-small nanoparticles (USNPs) enclosed in silica shells loaded with cisplatin prodrug (NAs-cisPt) combined with ionizing radiation (IR). The cytotoxic effects and DNA damage induction were evaluated in PDAC cell lines (MIA PaCa2, SUIT2-028) and primary culture (PDAC3) in vitro and in the chorioallantoic membrane (CAM) in ovo model. Unlike NAs, NAs-cisPt affected the cell viability in MIA PaCa2 and SUIT2-028 cells. Furthermore, NAs-cisPt showed increased γH2AX expression up to 24 h post-IR and reduced β-globin amplifications resulting in apoptosis induction at DNA and protein levels. Similarly, combined treatment of NAs-cisPt + IR in PDAC3 and SUIT2-028 CAM models showed enhanced DNA damage and apoptosis leading to tumor growth delay. Our results demonstrate an increased cytotoxic effect of NAs-cisPt, particularly through its release of the cisplatin prodrug. As cisplatin is a well-known radiosensitizer, administration of cisplatin prodrug in a controlled fashion through encapsulation is a promising new treatment approach which merits further investigation in combination with other radiosensitizing agents.