IL1-Induced JAK/STAT Signaling Is Antagonized by TGFβ to Shape CAF Heterogeneity in Pancreatic Ductal Adenocarcinoma

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.

Myeloid cell-derived apCAFs promote HNSCC progression by regulating proportion of CD4+ and CD8+ T cells

It is well-known that cancer-associated fibroblasts (CAFs) are involved in the desmoplastic responses in Head and Neck Squamous Cell Carcinoma (HNSCC). CAFs are pivotal in the tumor microenvironment (TME) molding, and exert a profound influence on tumor development. The origin and roles of CAFs, however, are still unclear in the HNSCC, especially antigen-presenting cancer-associated fibroblasts (apCAFs). Our current study tried to explore the origin, mechanism, and function of the apCAFs in the HNSCC. Data from single-cell transcriptomics elucidated the presence of apCAFs in the HNSCC. Leveraging cell trajectory and Cellchat analysis along with robust lineage-tracing assays revealed that apCAFs were primarily derived from myeloid cells. This transdifferentiation was propelled by the macrophage migration inhibitory factor (MIF), which was secreted by tumor cells and activated the JAK/STAT3 signaling pathway. Analysis of the TCGA database has revealed that markers of apCAFs were inversely correlated with survival rates in patients with HNSCC. In vivo experiments have demonstrated that apCAFs could facilitate tumor progression. Furthermore, apCAFs could modulate ratio of CD4+ T cells/CD8+ T cells, such as higher ratio of CD4+ T cells/CD8+ T cells could promote tumor progression. Most importantly, data from in vivo assays revealed that inhibitors of MIF and p-STAT3 could significantly inhibit the OSCC growth. Therefore, our findings show potential innovative therapeutic approaches for the HNSCC.Significance: ApCAFs derived from myeloid cells promote the progression of HNSCC by increasing the ratio of CD4+/CD8+ cells, indicating potential novel targets to be used to treat the human HNSCC.

Interleukin-6 related signaling pathways as the intersection between chronic diseases and sepsis

Sepsis is associated with immune dysregulated and organ dysfunction due to severe infection. Clinicians aim to restore organ function, rather than prevent diseases that are prone to sepsis, resulting in high mortality and a heavy public health burden. Some chronic diseases can induce sepsis through inflammation cascade reaction and Cytokine Storm (CS). Interleukin (IL)-6, the core of CS, and its related signaling pathways have been considered as contributors to sepsis. Therefore, it is important to study the relationship between IL-6 and its related pathways in sepsis-related chronic diseases. This review generalized the mechanism of sepsis-related chronic diseases via IL-6 related pathways with the purpose to take rational management for these diseases. IL-6 related signaling pathways were sought in Kyoto Encyclopedia of Genes and Genomes (KEGG), and retrieved protein-protein interaction in the Search for Interaction Genes tool (STRING). In PubMed and Google Scholar, the studies were searched out, which correlating to IL-6 related pathways and associating with the pathological process of sepsis. Focused on the interactions of sepsis and IL-6 related pathways, some chronic diseases have been studied for association with sepsis, containing insulin resistance, Alcoholic liver disease (ALD), Alzheimer disease (AD), and atherosclerosis. This article summarized the inflammatory mechanisms of IL-6 cross-talked with other mediators of some chronic diseases in vitro, animal models, and human experiments, leading to the activation of pathways and accelerating the progression of sepsis. The clinicians should be highlight to this kind of diseases and more clinical trials are needed to provide more reliable theoretical basis for health policy formulation.

Spatial Transcriptomics Reveals Cancer and Stromal Cell Heterogeneity Between Center and Invasive Front of Pancreatic Cancer

Intratumor heterogeneity is considered a major cause of treatment failure in pancreatic ductal adenocarcinoma (PDAC). In recent years, marked heterogeneity at the genomic and transcriptional level has been revealed, but the spatial distribution of the heterogeneous cell populations has not been considered. Yet, it is assumed that cancer cells at the invasive front are endowed with enhanced migratory and invasive properties, although evidence is scanty, and cancer-associated fibroblasts (CAFs) in this location have not been characterized. In this study, digital spatial profiling was used to compare the transcriptional profiles of cancer cells and CAFs in the tumor center versus the invasive front of human PDAC. Four well-differentiated PDACs with conventional morphology were investigated with the GeoMx system (Nanostring). Regions of interest were analyzed in the tumor center and at the invasive front using a whole transcriptome assay in the cancer cell and CAF segments separately. Three of the PDACs harbored mutated KRAS, whereas the fourth case was confirmed wild-type KRAS. Substantial inter-regional heterogeneity was identified, with increased activity of pathways associated with cellular stress (including TNFα-signaling via NFκB, hypoxia, P53 pathway), proliferation (MYC targets, mitotic spindle), glycolysis, and epithelial-mesenchymal transition (EMT) at the invasive front in both the cancer cell and CAF segments compared with the center of the tumor. Immunohistochemical validation on 17 PDACs of well, moderate, and poor differentiation confirmed significant inter-regional heterogeneity in the expression level of markers of EMT and glycolysis. The results of this study show that in PDAC, transcriptional profiles of both cancer cells and CAFs differ between the center of the tumor and the invasive front.

TGF-β signaling orchestrates cancer-associated fibroblasts in the tumor microenvironment of human hepatocellular carcinoma: unveiling insights and clinical significance

Liver cancer, specifically hepatocellular carcinoma (HCC), stands out as one of the most formidable solid tumors, characterized by a dauntingly low survival rate. At the forefront of the tumor microenvironment (TME) orchestrating the initiation and advancement of HCC are cancer-associated fibroblasts (CAFs). TGF-β, widely recognized as a potent activator of CAFs, not only regulates their activity but also assumes a pivotal role in the metastatic journey of the tumor. In our recent study, drawing from the GEO database, we identified two fibroblast subtypes in HCC through single-cell RNA sequencing (scRNA-seq) and explore the expression and distribution of TGF-β and its receptors in the TME of HCC. Subsequently, we investigated the interactions between tumor cells expressing high levels (TGFB1high) and low levels (TGFB1low) of TGF-β in the HCC TME and the two subtypes of CAFs. We also employed multi-color immunohistochemistry (mIHC) technology to examine the expressions of FAP, α-SMA, CD4, Foxp3, and TGF-β in HCC tissues within a tissue microarray. Additionally, we analyzed clinical associations, prognostic values, and the correlation of these molecules. These insights advance our understanding of the molecular mechanisms driving HCC progression and underscore the intricate interplay between tumor cells and the stromal components of the TME.

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.

The Immune-Genomics of Cholangiocarcinoma: A Biological Footprint to Develop Novel Immunotherapies

Cholangiocarcinoma (CCA) represents approximately 3% of all gastrointestinal cancers and is a highly heterogeneous and aggressive malignancy originating from the epithelial cells of the biliary tree. CCA is classified by anatomical location into intrahepatic (iCCA), extrahepatic (eCCA), gallbladder cancer (GBC), and ampullary cancers. Although considered a rare tumor, CCA incidence has risen globally, particularly due to the increased diagnosis of iCCA. Genomic and immune profiling studies have revealed significant heterogeneity within CCA, leading to the identification of molecular subtypes and actionable genetic alterations in 40-60% of cases, particularly in iCCA. Among these, FGFR2 rearrangements or fusions (7-15%) and IDH1 mutations (10-20%) are common in iCCA, while HER2 amplifications/overexpression are more frequent in eCCA and GBC. The tumor-immune microenvironment (TIME) of CCAs plays an active role in the pathogenesis and progression of the disease, creating a complex and plastic environment dominated by immune-suppressive populations. Among these, cancer-associated fibroblasts (CAFs) are a key component of the TIME and are associated with worse survival due to their role in maintaining a poorly immunogenic landscape through the deposition of stiff extracellular matrix and release of pro-tumor soluble factors. Improved understanding of CCA tumor biology has driven the development of novel treatments. Combination therapies of cisplatin and gemcitabine with immune checkpoint inhibitors (ICIs) have replaced the decade-long standard doublet chemotherapy, becoming the new standard of care in patients with advanced CCA. However, the survival improvements remain modest prompting research into more effective ways to target the TIME of CCAs. As key mechanisms of immune evasion in CCA are uncovered, novel immune molecules emerge as potential therapeutic targets. Current studies are exploring strategies targeting multiple immune checkpoints, angiogenesis, and tumor-specific antigens that contribute to immune escape. Additionally, the success of ICIs in advanced CCA has led to interest in their application in earlier stages of the disease, such as in adjuvant and neoadjuvant settings. This review offers a comprehensive overview of the immune biology of CCAs and examines how this knowledge has guided clinical drug development, with a focus on both approved and emergent treatment strategies.

Leveraging Single-Cell Multi-Omics to Decode Tumor Microenvironment Diversity and Therapeutic Resistance

Recent developments in single-cell multi-omics technologies have provided the ability to identify diverse cell types and decipher key components of the tumor microenvironment (TME), leading to important advancements toward a much deeper understanding of how tumor microenvironment heterogeneity contributes to cancer progression and therapeutic resistance. These technologies are able to integrate data from molecular genomic, transcriptomic, proteomics, and metabolomics studies of cells at a single-cell resolution scale that give rise to the full cellular and molecular complexity in the TME. Understanding the complex and sometimes reciprocal relationships among cancer cells, CAFs, immune cells, and ECs has led to novel insights into their immense heterogeneity in functions, which can have important consequences on tumor behavior. In-depth studies have uncovered immune evasion mechanisms, including the exhaustion of T cells and metabolic reprogramming in response to hypoxia from cancer cells. Single-cell multi-omics also revealed resistance mechanisms, such as stromal cell-secreted factors and physical barriers in the extracellular matrix. Future studies examining specific metabolic pathways and targeting approaches to reduce the heterogeneity in the TME will likely lead to better outcomes with immunotherapies, drug delivery, etc., for cancer treatments. Future studies will incorporate multi-omics data, spatial relationships in tumor micro-environments, and their translation into personalized cancer therapies. This review emphasizes how single-cell multi-omics can provide insights into the cellular and molecular heterogeneity of the TME, revealing immune evasion mechanisms, metabolic reprogramming, and stromal cell influences. These insights aim to guide the development of personalized and targeted cancer therapies, highlighting the role of TME diversity in shaping tumor behavior and treatment outcomes.

Cancer-associated fibroblasts as therapeutic targets for cancer: advances, challenges, and future prospects

Research into cancer treatment has been mainly focused on developing therapies to directly target cancer cells. Over the past decade, extensive studies have revealed critical roles of the tumour microenvironment (TME) in cancer initiation, progression, and drug resistance. Notably, cancer-associated fibroblasts (CAFs) have emerged as one of the primary contributors in shaping TME, creating a favourable environment for cancer development. Many preclinical studies have identified promising targets on CAFs, demonstrating remarkable efficacy of some CAF-targeted treatments in preclinical models. Encouraged by these compelling findings, therapeutic strategies have now advanced into clinical evaluation. We aim to provide a comprehensive review of relevant subjects on CAFs, including CAF-related markers and targets, their multifaceted roles, and current landscape of ongoing clinical trials. This knowledge can guide future research on CAFs and advocate for clinical investigations targeting CAFs.

Targeting Triple NK Cell Suppression Mechanisms: A Comprehensive Review of Biomarkers in Pancreatic Cancer Therapy

Pancreatic ductal adenocarcinoma (PDAC) is an aggressive cancer with poor outcomes due to frequent recurrence, metastasis, and resistance to treatment. A major contributor to this resistance is the tumor's ability to suppress natural killer (NK) cells, which are key players in the immune system's fight against cancer. In PDAC, the tumor microenvironment (TME) creates conditions that impair NK cell function, including reduced proliferation, weakened cytotoxicity, and limited tumor infiltration. This review examines how interactions between tumor-derived factors, NK cells, and the TME contribute to tumor progression and treatment resistance. To address these challenges, we propose a new "Triple NK Cell Biomarker Approach". This strategy focuses on identifying biomarkers from three critical areas: tumor characteristics, TME factors, and NK cell suppression mechanisms. This approach could guide personalized treatments to enhance NK cell activity. Additionally, we highlight the potential of combining NK cell-based therapies with conventional treatments and repurposed drugs to improve outcomes for PDAC patients. While progress has been made, more research is needed to better understand NK cell dysfunction and develop effective therapies to overcome these barriers.

Facilitation of Tumor Stroma-Targeted Therapy: Model Difficulty and Co-Culture Organoid Method

Background: Tumors, as intricate ecosystems, comprise oncocytes and the highly dynamic tumor stroma. Tumor stroma, representing the non-cancerous and non-cellular composition of the tumor microenvironment (TME), plays a crucial role in oncogenesis and progression, through its interactions with biological, chemical, and mechanical signals. This review aims to analyze the challenges of stroma mimicry models, and highlight advanced personalized co-culture approaches for recapitulating tumor stroma using patient-derived tumor organoids (PDTOs). Methods: This review synthesizes findings from recent studies on tumor stroma composition, stromal remodeling, and the spatiotemporal heterogeneities of the TME. It explores popular stroma-related models, co-culture systems integrating PDTOs with stromal elements, and advanced techniques to improve stroma mimicry. Results: Stroma remodeling, driven by stromal cells, highlights the dynamism and heterogeneity of the TME. PDTOs, derived from tumor tissues or cancer-specific stem cells, accurately mimic the tissue-specific and genetic features of primary tumors, making them valuable for drug screening. Co-culture models combining PDTOs with stromal elements effectively recreate the dynamic TME, showing promise in personalized anti-cancer therapy. Advanced co-culture techniques and flexible combinations enhance the precision of tumor-stroma recapitulation. Conclusions: PDTO-based co-culture systems offer a promising platform for stroma mimicry and personalized anti-cancer therapy development. This review underscores the importance of refining these models to advance precision medicine and improve therapeutic outcomes.

Genetics and biology of pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) poses a grim prognosis for patients. Recent multidisciplinary research efforts have provided critical insights into its genetics and tumor biology, creating the foundation for rational development of targeted and immune therapies. Here, we review the PDAC genomic landscape and the role of specific oncogenic events in tumor initiation and progression, as well as their contributions to shaping its tumor biology. We further summarize and synthesize breakthroughs in single-cell and metabolic profiling technologies that have illuminated the complex cellular composition and heterotypic interactions of the PDAC tumor microenvironment, with an emphasis on metabolic cross-talk across cancer and stromal cells that sustains anabolic growth and suppresses tumor immunity. These conceptual advances have generated novel immunotherapy regimens, particularly cancer vaccines, which are now in clinical testing. We also highlight the advent of KRAS targeted therapy, a milestone advance that has transformed treatment paradigms and offers a platform for combined immunotherapy and targeted strategies. This review provides a perspective summarizing current scientific and therapeutic challenges as well as practice-changing opportunities for the PDAC field at this major inflection point.

Single cell and spatial analysis of immune-hot and immune-cold tumours identifies fibroblast subtypes associated with distinct immunological niches and positive immunotherapy response

Cancer-associated Fibroblasts (CAFs) have emerged as critical regulators of anti-tumour immunity, with both beneficial and detrimental properties that remain poorly characterised. To investigate this, we performed single-cell and spatial transcriptomic analysis, comparing head & neck squamous cell carcinoma (HNSCC) subgroups, which although heterogenous, can be considered broadly immune-hot and immune-cold (human papillomavirus [HPV]+ve and HPV-ve tumours respectively). This identified six fibroblast subpopulations, including two with immunomodulatory gene expression profiles (IL-11 + inflammatory [i]CAF and CCL19 + fibroblastic reticular cell [FRC]-like). IL-11 + iCAF were spatially associated with inflammatory monocytes and regulated in vitro through synergistic activation of canonical NF-κB signalling by IL-1β and TNF-α. FRC-like were enriched in immune-hot HPV+ve tumours, associated with CD4 + T-cells and B-cells in tertiary lymphoid structures and regulated through non-canonical NF-κB signalling via lymphotoxin. Pan-cancer analysis revealed several 'iCAF' subgroups present in both normal and cancer tissues; IL11 + iCAF were found in cancers from the gastrointestinal (GI) tract and transcriptomically distinct from iCAFs previously described in pancreatic and breast cancers with greater inflammatory properties; FRC-like fibroblasts were present at low frequencies in all tumour types, and were associated with significantly better survival in patients receiving checkpoint immunotherapy. This work clarifies and expands current literature on immunomodulatory CAFs, highlighting links with important immunological niches.

Up-regulated ITGB4 promotes hepatocellular carcinoma metastasis by activating hypoxia-mediated glycolysis and cancer-associated fibroblasts

The pre-metastatic niche constructed by cancer-associated fibroblasts (CAFs) plays a key role in the hypoxic tumor microenvironment (TME), promoting hepatocellular carcinoma (HCC) metastasis. Integrin, which is involved in cell-to-cell or cell-to-matrix interactions and TME regulation, affects tumor metastasis. However, the complex interactions between integrin-mediated HCC cells and CAFs remain unclear. Co-culture experiments were used to assess the behaviors of HCC cells and CAFs, demonstrating HCC metastatic traits and CAFs activation in vitro. Transcriptome sequencing analysis and molecular detection identified key genes, with overexpression and knockdown experiments further confirming their roles in HCC progression. Xenograft models validated these findings in vivo. We showed that HCC cells induced the conversion of normal hepatic stellate cells (HSCs) into CAFs and recruit additional CAFs, driven by lactate produced by HCC. Integrin beta 4 (ITGB4) was identified as a key gene in the process. Inhibiting ITGB4 reduced lactate secretion, reversed CAFs activation and recruitment, and decreased HCC metastasis, while overexpressing ITGB4 significantly enhanced these malignant phenotypes. ITGB4 influences glycolysis and HCC metastasis through the AKT/HK2 signaling pathway, and CAFs activation and recruitment through the TGF-β/Smads signaling pathway. Compared to tumors derived from control cells, ITGB4-knockdown tumors showed fewer and smaller intrahepatic metastatic nodules, reduced lactate production and CAFs formation, along with inhibition of AKT/HK2 and TGF-β/Smads signaling pathways. Our findings highlighted the impact of hypoxia on HCC progression, revealing the roles of ITGB4-mediated glycolysis and lactate-induced CAFs in the pre-metastatic niche on HCC metastasis.

Depletion of Adipose Stroma-Like Cancer-Associated Fibroblasts Potentiates Pancreatic Cancer Immunotherapy

SIGNIFICANCE

This study shows that populations of CAFs have distinct effects on pancreatic cancer progression and shows that depletion of CAFs expressing adipose markers potentiates tumor/metastasis suppression effects of immune checkpoint blockade.

Convergent inducers and effectors of T cell paralysis in the tumour microenvironment

Tumorigenesis embodies the formation of a heterotypic tumour microenvironment (TME) that, among its many functions, enables the evasion of T cell-mediated immune responses. Remarkably, most TME cell types, including cancer cells, fibroblasts, myeloid cells, vascular endothelial cells and pericytes, can be stimulated to deploy immunoregulatory programmes. These programmes involve regulatory inducers (signals-in) and functional effectors (signals-out) that impair CD8+ and CD4+ T cell activity through cytokines, growth factors, immune checkpoints and metabolites. Some signals target specific cell types, whereas others, such as transforming growth factor-β (TGFβ) and prostaglandin E2 (PGE2), exert broad, pleiotropic effects; as signals-in, they trigger immunosuppressive programmes in most TME cell types, and as signals-out, they directly inhibit T cells and also modulate other cells to reinforce immunosuppression. This functional diversity and redundancy pose a challenge for therapeutic targeting of the immune-evasive TME. Fundamentally, the commonality of regulatory programmes aimed at abrogating T cell activity, along with paracrine signalling between cells of the TME, suggests that many normal cell types are hard-wired with latent functions that can be triggered to prevent inappropriate immune attack. This intrinsic capability is evidently co-opted throughout the TME, enabling tumours to evade immune destruction.

AMIGO2 characterizes cancer-associated fibroblasts in metastatic colon cancer and induces the release of paracrine active tumorigenic secretomes

Secretomes of cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC) contribute to malignancy. Detailed knowledge is available on the components and functions of CAF secretomes. Little is known about the regulation of CAF secretomes. Here, we searched for receptor-like membrane-bound molecules in CAFs, which may regulate the production and release of tumor-activating secretomes. The adhesion molecule with Ig-like domain 2 (AMIGO2) was significantly upregulated in cultivated CAFs compared to normal tissue-associated fibroblasts (NAFs), and this was confirmed in patient-derived tissues. AMIGO2 expression was low or absent in healthy colon, significantly increased in fibroblasts of primary CRC, and highest in the stromal tissues of CRC-derived liver metastases. AMIGO2 expression in CAFs correlated with a higher T-category, increased lymph node metastasis, progressed tumor stages and was associated with reduced survival in different cohorts of CRC patients. Interestingly, AMIGO2 expression was induced by transforming growth factor-β and higher in female patients, who exhibit a more aggressive disease course. In functional studies, conditioned media of NAFs with experimentally induced AMIGO2 overexpression enhanced proliferation and migration of different CRC tumor cells, while siRNA-mediated inhibition of AMIGO2 in CAFs attenuated these effects. Accordingly, therapeutic inhibition of the receptor-like AMIGO2 protein in CRC CAFs could prevent tumorigenic secretomes in CRC. © 2024 The Author(s). The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

The role of transcription factors in the crosstalk between cancer-associated fibroblasts and tumor cells

BACKGROUND

Transcription factors (TFs) fulfill a critical role in the formation and maintenance of different cell types during the developmental process as well as disease. It is believed that cancer-associated fibroblasts (CAFs) are activation status of tissue-resident fibroblasts or derived from form other cell types via transdifferentiation or dedifferentiation. Despite a subgroup of CAFs exhibit anti-cancer effects, most of them are reported to exert effects on tumor progression, further indicating their heterogeneous origin.

AIM OF REVIEW

This review aimed to summarize and review the roles of TFs in the reciprocal crosstalk between CAFs and tumor cells, discuss the emerging mechanisms, and their roles in cell-fate decision, cellular reprogramming and advancing our understanding of the gene regulatory networks over the period of cancer initiation and progression.

KEY SCIENTIFIC CONCEPTS OF REVIEW

This manuscript delves into the key contributory factors of TFs that are involved in activating CAFs and maintaining their unique states. Additionally, it explores how TFs play a pivotal and multifaceted role in the reciprocal crosstalk between CAFs and tumor cells. This includes their involvement in processes such as epithelial-mesenchymal transition (EMT), proliferation, invasion, and metastasis, as well as metabolic reprogramming. TFs also have a role in constructing an immunosuppressive microenvironment, inducing resistance to radiation and chemotherapy, facilitating angiogenesis, and even 'educating' CAFs to support the malignancies of tumor cells. Furthermore, this manuscript delves into the current status of TF-targeted therapy and considers the future directions of TFs in conjunction with anti-CAFs therapies to address the challenges in clinical cancer treatment.

Multi-omics analysis unveils the role of inflammatory cancer-associated fibroblasts in chordoma progression

Cancer-associated fibroblasts (CAFs) constitute the primary cellular component of the stroma in chordomas, characterized by an abundance of mucinous stromal elements, potentially facilitating their initiation and progression; however, this inference has yet to be fully confirmed. In this study, single-cell RNA sequencing (scRNA-seq), spatial transcriptomics (ST), bulk RNA-seq, multiplexed quantitative immunofluorescence (QIF), and in vivo and in vitro experiments were performed to determine the heterogeneity, spatial distribution, and clinical significance of CAFs in chordoma. ScRNA-seq was performed on 87,693 single cells derived from seven tumor samples and four control nucleus pulposus samples. A distinct CAF cluster distinguished by the upregulated expression of inflammatory genes and enriched functionality in activating inflammation-associated cells was identified. Pseudotime trajectory and cell communication analyses suggested that this inflammatory CAF (iCAF) subset originated from normal fibroblasts and interacted extensively with tumors and various other cell types. By integrating the scRNA-seq results with ST, the presence of iCAF in chordoma tissue was further confirmed, indicating their positioning at a distance from the tumor cells. Bulk RNA-seq data analysis from 126 patients revealed a correlation between iCAF signature scores, chordoma invasiveness, and poor prognosis. QIF validation involving an additional 116 patients found that although iCAFs were not in close proximity to tumor cells compared with other CAF subsets, their density correlated with malignant tumor phenotypes and adverse outcomes. In vivo and in vitro experiments further confirmed that iCAFs accelerate the malignant progression of chordomas. These findings could provide insights into the development of novel therapeutic strategies. © 2024 The Pathological Society of Great Britain and Ireland.

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.

Synovial mast cells and osteoarthritis: Current understandings and future perspectives

Osteoarthritis (OA) is a prevalent joint disease worldwide that significantly impacts the quality of life of individuals, particularly those in middle-aged and elderly populations. OA was initially considered as non-inflammatory arthritis, but recent studies have identified a substantial number of immune responses in OA, leading to the recognition of inflammation as a key factor in its pathogenesis. An increasing number of studies have found that mast cell (MC) and MC-secreted inflammatory mediators and cytokines are notably increased in the synovial fluid of OA patients, indicating a potential association between MCs and the onset and progression of synovial inflammation. The present review aims to summarize the significance and mechanism of MCs in the pathogenesis of OA. Meanwhile, we also discuss the clinical potential of using MCs as therapeutic target for OA therapy. Modulating the activities of MCs or the mediators of MCs in the synovial fluid inflammatory microenvironment will be promising new options for the treatment of OA.

Single-cell transcriptomics reveal the prognostic roles of epithelial and T cells and DNA methylation-based prognostic models in pancreatic cancer

BACKGROUND

Pancreatic adenocarcinoma (PDAC) exhibits a complex microenvironment with diverse cell populations influencing patient prognosis. Single-cell RNA sequencing (scRNA-seq) was used to identify prognosis-related cell types, and DNA methylation (DNAm)-based models were developed to predict outcomes based on their cellular characteristics.

METHODS

We integrated scRNA-seq, bulk data, and clinical information to identify key cell populations associated with prognosis. The TCGA dataset was used for validation, and cell composition was inferred from DNAm data. Prognostic models were constructed based on cell-type-specific DNAm markers, and genomic features were compared across risk groups. Nomograms were created to assess treatment responses in different risk levels.

RESULTS

Epithelial and T cells were major prognostic factors. Genomic analysis showed that epithelial cells in PDAC followed a malignant trajectory. DNAm data from TCGA confirmed the association of higher epithelial and T cell proportions with worse prognosis. Prognostic models based on DNAm markers of these cells effectively predicted patient survival, especially 5-year overall survival (AUC = 0.834). High-risk group with epithelial cell model showed altered pathways (tight junctions, NOTCH, and P53 signaling), while high-risk group with T cell model had changes in glycolysis, hypoxia, and NOTCH signaling, with more KRAS or TP53 mutations. Low-risk groups in the T cell model displayed stronger antitumor immune responses. Treatment predictions and nomograms were developed for clinical use.

CONCLUSIONS

scRNA-seq and DNAm data integration enabled the creation of predictive models based on epithelial and T cell-specific methylation patterns, offering robust prognosis prediction for PDAC patients.

C3+ cancer-associated fibroblasts promote tumor growth and therapeutic resistance in gastric cancer via activation of the NF-κB signaling pathway

BACKGROUND

Gastric cancer (GC) remains one of the most lethal malignancies globally, with limited therapeutic options. Cancer-associated fibroblasts (CAFs), a diverse population of stromal cells within the tumor microenvironment (TME), play a central role in tumor progression and therapeutic resistance. However, the specific markers identifying tumor-promoting CAF subsets in GC have yet to be fully characterized.

METHODS

Through animal studies and RNA sequencing, complement C3 (C3) emerged as a key marker linked to tumor-promoting CAF subsets. Single-cell sequencing and multiplex immunofluorescence staining confirmed that C3 expression is predominantly localized within CAFs. Independent cohort analyses demonstrated a strong association between elevated levels of C3+ CAFs and poor clinical outcomes in GC patients. To further investigate, small interfering RNA (siRNA)-mediated knockdown of C3 in CAFs was employed in vitro, with subsequent experiments, including cell migration assays, cell viability assays, and immunofluorescence, revealing significant functional impacts.

RESULTS

C3 secreted by CAFs promoted Epithelial-mesenchymal transition (EMT) and accelerated cancer cell migration. Patients with minimal C3+ CAF infiltration exhibited a higher probability of deriving therapeutic benefit from adjuvant treatments. Furthermore, C3+ CAFs were associated with immunosuppressive effects and an immune-evasive microenvironment marked by CD8 + T cell dysfunction. A lower prevalence of C3+ CAFs correlated with improved responsiveness to immunotherapy in GC patients. Enrichment analysis highlighted pronounced activation of the NF-κB signaling pathway in C3+ CAFs relative to their C3- counterparts, supported by elevated phosphorylation levels of IKK, IκBα, and p65 in C3+ CAFs compared to both C3- CAFs and normal fibroblasts (NFs). Silencing p65 nuclear translocation in CAFs through siRNA significantly suppressed C3 secretion.

CONCLUSIONS

The study suggests that NF-κB pathway-mediated CAF activation enhances C3 secretion, driving EMT, migration, chemoresistance, and immune evasion in GC progression. Targeting the NF-κB/C3 signaling axis in CAFs may offer a viable therapeutic strategy for GC management.

Cancer-associated fibroblasts, tumor and radiotherapy: interactions in the tumor micro-environment

Cancer-associated fibroblasts (CAFs) represent a group of genotypically non-malignant stromal cells in the tumor micro-environment (TME) of solid tumors that encompasses up to 80% of the tumor volume. Even though the phenotypic diversity and plasticity of CAFs complicates research, it is well-established that CAFs can affect many aspects of tumor progression, including growth, invasion and therapy resistance. Although anti-tumorigenic properties of CAFs have been reported, the majority of research demonstrates a pro-tumorigenic role for CAFs via (in)direct signaling to cancer cells, immunomodulation and extracellular matrix (ECM) remodeling. Following harsh therapeutic approaches such as radio- and/or chemotherapy, CAFs do not die but rather become senescent. Upon conversion towards senescence, many pro-tumorigenic characteristics of CAFs are preserved or even amplified. Senescent CAFs continue to promote tumor cell therapy resistance, modulate the ECM, stimulate epithelial-to-mesenchymal transition (EMT) and induce immunosuppression. Consequently, CAFs play a significant role in tumor cell survival, relapse and potentially malignant transformation of surviving cancer cells following therapy. Modulating CAF functioning in the TME therefore is a critical area of research. Proposed strategies to enhance therapeutic efficacy include reverting senescent CAFs towards a quiescent phenotype or selectively targeting (non-)senescent CAFs. In this review, we discuss CAF functioning in the TME before and during therapy, with a strong focus on radiotherapy. In the future, CAF functioning in the therapeutic TME should be taken into account when designing treatment plans and new therapeutic approaches.

Blocking IL1RAP on cancer-associated fibroblasts in pancreatic ductal adenocarcinoma suppresses IL-1-induced neutrophil recruitment

BACKGROUND

Pancreatic ductal adenocarcinoma (PDAC) represents a major clinical challenge due to its tumor microenvironment, which exhibits immune-suppressive properties that facilitate cancer progression, metastasis, and therapy resistance. Interleukin 1 (IL-1) signaling has been implicated as a driver in this process. Mechanistically, both IL-1α and IL-1β bind to the IL-1 receptor type 1, forming a complex with IL-1-receptor accessory protein (IL1RAP), which triggers downstream signaling pathways. The IL1RAP blocking antibody nadunolimab is currently in clinical development, but the precise consequences of inhibiting IL-1 signaling in PDAC remains elusive.

METHODS

To evaluate the biological relevance of blocking IL1RAP using nadunolimab in a PDAC animal model, human PDAC cells and cancer-associated fibroblasts (CAFs) were co-transplanted into mice. To study the underlying mechanisms of IL1RAP blockade ex vivo, co-cultured PDAC cells and CAFs were treated with nadunolimab prior to RNA sequencing. Migration assays were performed to assess how nadunolimab affects interactions between CAFs and myeloid immune cells. Finally, to establish a clinical correlation between IL1RAP expression and nadunolimab treatment effects, we analyzed tumor biopsies from a clinical phase I/II study in which nadunolimab was administered to patients.

RESULTS

In the xenograft mouse model, nadunolimab exhibited antitumor effects only when human CAFs were co-transplanted with PDAC cells. IL-1 stimulation induced CAFs to secrete chemokines that recruited neutrophils and monocytes. The secretion of this chemokine and the migration of myeloid cells were inhibited by nadunolimab. Media conditioned by IL-1-stimulated CAFs sustained a neutrophil population with a tissue invasion phenotype, an effect that was reversed by nadunolimab. In a cohort of metastatic late-stage PDAC patients receiving nadunolimab as monotherapy, high IL1RAP expression in tumors was associated with extended progression-free survival.

CONCLUSIONS

Our study demonstrates that targeting IL1RAP on CAFs inhibits IL-1-induced chemokine secretion and recruitment of neutrophils and monocytes, thereby counteracting the immunosuppressive microenvironment in PDAC. These findings highlight the therapeutic potential of targeting IL1RAP in PDAC.

Construction of 3D tumor in vitro models with an immune microenvironment exhibiting similar tumor properties and biomimetic physiological functionality

Tumors pose a serious threat to people's lives and health, and the complex tumor microenvironment is the biggest obstacle to their treatment. In contrast to the basic protein matrices typically employed in 2D or 3D cell culture systems, decellularized extracellular matrix (dECM) can create complex microenvironments. In this study, a combination of physicochemical methods was established to obtain liver decellularized extracellular matrix scaffolds (dLECMs) to provide mechanical support and cell adhesion sites. By co-culturing tumor cells, tumor-associated stromal cells and immune cells, an in vitro 3D tumor model with a biomimetic immune microenvironment was constructed. By utilizing microenvironment data obtained from human liver tumor tissues and refining the double seeding modeling process, 3D in vitro liver tumor-like tissues with a tumor immune microenvironment (TIME) were obtained and designated as reconstructed human liver cancer (RHLC). These tissues demonstrated similar tumor characteristics and exhibited satisfactory physiological functionality. The results of metabolic characterisation and mouse tumorigenicity testing verified that the constructed RHLC significantly increased in vitro drug resistance while also closely mimicking in vivo tissue metabolism. This opens up new possibilities for creating effective in vitro models for screening chemotherapy drugs.

Cancer-associated fibroblasts: heterogeneity, tumorigenicity and therapeutic targets

Cancer, characterized by its immune evasion, active metabolism, and heightened proliferation, comprises both stroma and cells. Although the research has always focused on parenchymal cells, the non-parenchymal components must not be overlooked. Targeting cancer parenchymal cells has proven to be a formidable challenge, yielding limited success on a broad scale. The tumor microenvironment(TME), a critical niche for cancer cell survival, presents a novel way for cancer treatment. Cancer-associated fibroblast (CAF), as a main component of TME, is a dynamically evolving, dual-functioning stromal cell. Furthermore, their biological activities span the entire spectrum of tumor development, metastasis, drug resistance, and prognosis. A thorough understanding of CAFs functions and therapeutic advances holds significant clinical implications. In this review, we underscore the heterogeneity of CAFs by elaborating on their origins, types and function. Most importantly, by elucidating the direct or indirect crosstalk between CAFs and immune cells, the extracellular matrix, and cancer cells, we emphasize the tumorigenicity of CAFs in cancer. Finally, we highlight the challenges encountered in the exploration of CAFs and list targeted therapies for CAF, which have implications for clinical treatment.

Patient-derived tumor organoid and fibroblast assembloid models for interrogation of the tumor microenvironment in esophageal adenocarcinoma

The tumor microenvironment (TME) comprises all non-tumor elements of cancer and strongly influences disease progression and phenotype. To understand tumor biology and accurately test new therapeutic strategies, representative models should contain both tumor cells and normal cells of the TME. Here, we describe and characterize co-culture tumor-derived organoids and cancer-associated fibroblasts (CAFs), a major component of the TME, in matrix-embedded assembloid models of esophageal adenocarcinoma (EAC). We demonstrate that the assembloid models faithfully recapitulate the differentiation status of EAC and different CAF phenotypes found in the EAC patient TME. We evaluate cell phenotypes by combining tissue-clearing techniques with whole-mount immunofluorescence and histology, providing a practical framework for the characterization of cancer assembloids.

Inhibition of JNK Signaling Overcomes Cancer-Associated Fibroblast-Mediated Immunosuppression and Enhances the Efficacy of Immunotherapy in Bladder Cancer

Currently, only 20% to 40% of patients with cancer benefit from immune checkpoint inhibitors. Understanding the mechanisms underlying the immunosuppressive tumor microenvironment (TME) and characterizing dynamic changes in the immunologic landscape during treatment are critical for improving responsiveness to immunotherapy. In this study, we identified JNK signaling in cancer-associated fibroblasts (CAF) as a regulator of the immunosuppressive TME. Single-cell RNA sequencing of bladder cancer samples treated with a JNK inhibitor revealed enhanced cytotoxicity and effector functions of CD8+ T cells. In untreated tumors, CAFs interacted frequently with CD8+ T cells and mediated their exhaustion. JNK inhibition abrogated the immunosuppression function of CAFs by downregulating the expression of thymic stromal lymphopoietin (TSLP), thereby restoring CD8+ T-cell cytotoxicity. In addition, blockade of CAF-derived TSLP in combination with anti-PD-1 treatment promoted tumor elimination by CD8+ T cells in vivo. Collectively, these results indicate that JNK signaling plays an important immunosuppressive role in the TME by promoting expression of TSLP in CAFs and suggest that inhibiting JNK signaling could be a promising immunotherapeutic strategy for cancer treatment. Significance: JNK signaling promotes the secretion of TSLP by bladder cancer-associated fibroblasts to impede CD8+ T-cell activity, which can be circumvented by combination treatment targeting JNK signaling and PD-1.

Bufadienolides from Chansu Injection Synergistically Enhances the Antitumor Effect of Erlotinib by Inhibiting the KRAS Pathway in Pancreatic Cancer

Background and Objectives: The Chansu injection (CSI), a sterile aqueous solution derived from Chansu, is applied in clinical settings to support antitumor and anti-radiation treatments. CSI's principal active components, bufadienolides (≥90%), demonstrate potential effects on pancreatic cancer (PDAC), but their underlying mechanisms remain unclear. This study aimed to elucidate the antitumor effects and pathways associated with CSI in PDAC. Methods: Network pharmacology and bioinformatics analyses explored CSI's mechanisms against PDAC. MTT, colony-formation, and migration assays evaluated CSI's impact on proliferation and migration in PANC-1 and MIA PACA-2 cells, both as a single agent and in combination with erlotinib (EGFR inhibitor). Cell cycle analysis employed flow cytometry. Animal experiments were performed on tumor-bearing mice, with targets and pathways assessed via molecular docking and western blotting. Results: CSI treatment suppressed PDAC cell proliferation and migration by inducing G2/M phase arrest. Network pharmacology, bioinformatics, and molecular docking indicated that CSI's anti-PDAC effects may involve EGFR pathway modulation, with CSI lowering p-EGFR/KRAS/p-ERK1/2 pathway expressions in PDAC cells. Additionally, sustained KRAS activation in mediating erlotinib resistance in PDAC and CSI potentiated erlotinib's antitumor effects through enhanced KRAS and p-ERK1/2 inhibition. CSI also enhanced erlotinib's efficacy in tumor-bearing mice without causing detectable toxicity in renal, cardiac, or hepatic tissues at therapeutic doses. Conclusions: CSI as an adjuvant used in antitumor and anti-radiation therapies enhanced erlotinib's antitumor effects through modulation of the KRAS pathway. CSI and erlotinib's synergistic interaction represents a promising approach for addressing erlotinib resistance in PDAC treatment.

Excess shed mesothelin disrupts pancreatic cancer cell clustering to impair peritoneal colonization

Peritoneum is the second most common site of metastasis in patients with pancreatic ductal adenocarcinoma (PDAC). Peritoneal colonization is impaired in PDAC cells with knockout (KO) of the cancer surface antigen mesothelin (MSLN) or by introducing Y318A mutation in MSLN to prevent binding to mucin-16 (MUC-16). MSLN has a membrane-bound form but is also shed to release soluble MSLN (sMSLN). Their individual roles in peritoneal metastasis are unknown. Here, a C-terminal truncated MSLN mutant (∆591) incapable of cell membrane insertion but proficient in secretion was engineered. Expression of ∆591 MSLN failed to rescue peritoneal metastasis in MSLN KO cells and inhibited peritoneal colonization when overexpressed in WT PDAC cells. Exposing PDAC cells to conditioned medium (CM) containing excess sMSLN impaired cancer cell clustering in vitro and in peritoneal fluid in vivo, while CM containing only Y318A sMSLN did not. These data demonstrate that interaction of membrane-bound MSLN with MUC-16 promotes cell clustering that is critical for efficient peritoneal metastasis. However, peritoneal colonization by MSLN KO cells was rescued by expression of ∆591 mutant MSLN bearing Y318A mutation, suggesting that sMSLN also has a MUC-16-independent role in peritoneal spread. Alterations in inflammatory signaling pathways occurred following KO cell exposure to CM containing sMSLN, and CM from cancer cells with intact peritoneal metastasis provoked increased KO cell secretion of IL-1α. While excess sMSLN inhibits cell clustering and peritoneal colonization, sMSLN may also promote PDAC peritoneal metastasis independent of MUC-16.

Disruption of cellular plasticity by repeat RNAs in human pancreatic cancer

Aberrant expression of repeat RNAs in pancreatic ductal adenocarcinoma (PDAC) mimics viral-like responses with implications on tumor cell state and the response of the surrounding microenvironment. To better understand the relationship of repeat RNAs in human PDAC, we performed spatial molecular imaging at single-cell resolution in 46 primary tumors, revealing correlations of high repeat RNA expression with alterations in epithelial state in PDAC cells and myofibroblast phenotype in cancer-associated fibroblasts (CAFs). This loss of cellular identity is observed with dosing of extracellular vesicles (EVs) and individual repeat RNAs of PDAC and CAF cell culture models pointing to cell-cell intercommunication of these viral-like elements. Differences in PDAC and CAF responses are driven by distinct innate immune signaling through interferon regulatory factor 3 (IRF3). The cell-context-specific viral-like responses to repeat RNAs provide a mechanism for modulation of cellular plasticity in diverse cell types in the PDAC microenvironment.

The role of tumor microenvironment and self-organization in cancer progression: Key insights for therapeutic development

Introduction

The tumor microenvironment (TME) plays a pivotal role in cancer progression, influencing tumor initiation, growth, invasion, metastasis, and response to therapies. This study explores the dynamic interactions within the TME, particularly focusing on self-organization-a process by which tumor cells and their microenvironment reciprocally shape one another, leading to cancer progression and resistance. Understanding these interactions can reveal new prognostic markers and therapeutic targets within the TME, such as extracellular matrix (ECM) components, immune cells, and cytokine signaling pathways.

Methods

A comprehensive search method was employed to investigate the current academic literature on TME, particularly focusing on self-organization in the context of cancer progression and resistance across the PubMed, Google Scholar, and Science Direct databases.

Results

Recent studies suggest that therapies that disrupt TME self-organization could improve patient outcomes by defeating drug resistance and increasing the effectiveness of conventional therapy. Additionally, this research highlights the essential of understanding the biophysical properties of the TME, like cytoskeletal alterations, in the development of more effective malignancy therapy.

Conclusion

This review indicated that targeting the ECM and immune cells within the TME can improve therapy effectiveness. Also, by focusing on TME self-organization, we can recognize new therapeutic plans to defeat drug resistance.

Macropinocytosis controls metabolic stress-driven CAF subtype identity in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) tumors are deficient in glutamine, an amino acid that tumor cells and CAFs use to sustain their fitness. In PDAC, both cell types stimulate macropinocytosis as an adaptive response to glutamine depletion. CAFs play a critical role in sculpting the tumor microenvironment, yet how adaptations to metabolic stress impact the stromal architecture remains elusive. In this study, we find that macropinocytosis functions to control CAF subtype identity when glutamine is limiting. Our data demonstrate that metabolic stress leads to an intrinsic inflammatory CAF (iCAF) program driven by MEK/ERK signaling. Utilizing in vivo models, we find that blocking macropinocytosis alters CAF subtypes and reorganizes the tumor stroma. Importantly, these changes in stromal architecture can be exploited to sensitize PDAC to immunotherapy and chemotherapy. Our findings demonstrate that metabolic stress plays a role in shaping the tumor microenvironment, and that this attribute can be harnessed for therapeutic impact.

Differential activity of MAPK signalling defines fibroblast subtypes in pancreatic cancer

Fibroblast heterogeneity is increasingly recognised across cancer conditions. Given their important contribution to disease progression, mapping fibroblasts' heterogeneity is critical to devise effective anti-cancer therapies. Cancer-associated fibroblasts (CAFs) represent the most abundant cell population in pancreatic ductal adenocarcinoma (PDAC). Whether CAF phenotypes are differently specified by PDAC cell lineages remains to be elucidated. Here, we reveal an important role for the MAPK signalling pathway in defining PDAC CAF phenotypes. We show that epithelial MAPK activity promotes the myofibroblastic differentiation of CAFs by sustaining the expression and secretion of TGF-β1. We integrate single-cell profiling of post-perturbation transcriptional responses from mouse models with cellular and spatial profiles of human tissues to define a MAPKhigh CAF (mapCAF) phenotype. We show that this phenotype associates with basal-like tumour cells and reduced frequency of CD8+ T cells. In addition to elevated MAPK activity, this mapCAF phenotype is characterized by TGF-β signalling, hypoxia responsive signatures, and immunoregulatory gene programs. Furthermore, the mapCAF signature is enriched in myofibroblastic CAFs from various cancer conditions and correlates with reduced response to immune checkpoint inhibition in melanoma. Altogether, our data expand our knowledge on CAF phenotype heterogeneity and reveal a potential strategy for targeting myofibroblastic CAFs in vivo.

Pathophysiology-Driven Approaches for Overcoming Nanomedicine Resistance in Pancreatic Cancer

Tumor heterogeneity poses a significant challenge in cancer therapy. To address this, we analyze pharmacotherapeutic challenges by categorizing them into static and dynamic barriers, reframing these challenges to improve drug delivery, efficacy, and the development of controlled-release nanomedicines (CRNMs). This pathophysiology-driven approach facilitates the design of novel therapeutics tailored to overcome obstacles in pancreatic ductal adenocarcinoma (PDAC) using nanotechnology. Advanced biomaterials in nanodrug delivery systems offer innovative solutions by combining controlled release, stimuli sensitivity, and smart design strategies. CRNMs are engineered to modulate spatiotemporal signaling and control drug release in PDAC, where resistance to conventional therapies is particularly high. This review explores pharmacokinetic considerations for nanomedicine design, RNA interference (RNAi) for stromal modulation, and the development of targeted nanomedicine strategies. Additionally, we highlight the limitations of current animal models in capturing the complexities of PDAC and discuss notable clinical failures, such as PEGylated hyaluronidase (Phase III HALO 109-301 trial) and evofosfamide (TH-302) with gemcitabine (MAESTRO trial), underscoring the need for improved models and treatment strategies. By targeting pathways like Notch and Hedgehog and incorporating stimuli-sensitive and pathway-modulating agents, CRNMs offer a promising avenue to enhance drug penetration and efficacy, reshaping the paradigm of pancreatic cancer treatment.

Targeting cancer-associated fibroblasts with pirfenidone: A novel approach for cancer therapy

Cancer-associated fibroblasts (CAFs) are a heterogeneous cell population within the tumor that have recently come into the spotlight. By extracellular matrix (ECM) remodeling and robust cross-talk with cancer cells via different secretions such as cytokines, chemokines, and growth factors, CAFs contribute to cancer progression and poorer prognoses in patients. Novel candidates have been developed to inhibit CAFs; however, due to safety and efficacy issues, none have successfully passed clinical trials. Despite these shortcomings, one concept embraced by many researchers is to repurpose non-oncology drugs with potential anti-cancer properties for cancer treatment. One such example is pirfenidone (PFD), an oral anti-fibrotic medication, primarily administered for idiopathic pulmonary fibrosis. Emerging evidence suggests that PFD has promising anti-cancer effects, mainly manifesting through targeting CAFs. With inhibitory effects on CAFs, PFD restricts cancer proliferation, metastasis, immunosuppression, drug resistance, and tumor stiffness. To improve efficacy and minimize adverse effects, several innovative approaches have been proposed for targeting CAFs via PFD. Interestingly, combination therapy comprising PFD and chemotherapeutics e.g. doxorubicin has shown synergistic anti-cancer effects while protecting normal tissue. Furthermore, novel drug delivery systems, e.g. biomimetic liposomes and multilayer core-shell nanoparticles, have enhanced the pharmacokinetic properties of PFD and further increased its intratumoral delivery. Single-cell RNA sequencing (scRNA-seq) has also been suggested to characterize different subpopulations of CAFs and design precise PFD-based therapeutic strategies. Herein, we discuss the promising anti-cancer effects of PFD via inhibition of CAFs. We then provide findings on novel PFD-based approaches to target CAFs using combination therapy, nanocarrier-based drug delivery, and scRNA-seq.

Botanical drugs and their natural compounds: a neglected treasury for inhibiting the carcinogenesis of pancreatic ductal adenocarcinoma

CONTEXT

Pancreatic ductal adenocarcinoma (PDAC), which is characterized by its malignant nature, presents challenges for early detection and is associated with a poor prognosis. Any strategy that can interfere with the beginning or earlier stage of PDAC greatly delays disease progression. In response to this intractable problem, the exploration of new drugs is critical to reduce the incidence of PDAC.

OBJECTIVE

In this study, we summarize the mechanisms of pancreatitis-induced PDAC and traditional Chinese medicine (TCM) theory and review the roles and mechanisms of botanical drugs and their natural compounds that can inhibit the process of pancreatitis-induced PDAC.

METHODS

With the keywords 'chronic pancreatitis', 'TCM', 'Chinese medicinal formulae', 'natural compounds', 'PDAC' and 'pancreatic cancer', we conducted an extensive literature search of the PubMed, Web of Science, and other databases to identify studies that effectively prevent PDAC in complex inflammatory microenvironments.

RESULTS

We summarized the mechanism of pancreatitis-induced PDAC. Persistent inflammatory microenvironments cause multiple changes in the pancreas itself, including tissue damage, abnormal cell differentiation, and even gene mutation. According to TCM, pancreatitis-induced PDAC is the process of 'dampness-heat obstructing the spleen and deficiency due to stagnation' induced by a variety of pathological factors. A variety of botanical drugs and their natural compounds, such as Chaihu classical formulae, flavonoids, phenolics, terpenoids, etc., may be potential drugs to interfere with the development of PDAC via reshaping the inflammatory microenvironment by improving tissue injury and pancreatic fibrosis.

CONCLUSIONS

Botanical drugs and their natural compounds show great potential for preventing PDAC in complex inflammatory microenvironments.

Pirfenidone antagonizes TGF-β1-mediated gabapentin resistance via reversal of desmoplasia and the 'cold' microenvironment in pancreatic cancer

Owing to the desmoplastic stroma constituted by cancer-associated fibroblasts (CAFs), few immune cells infiltrate the pancreatic ductal adenocarcinoma (PDAC). Gabapentin can impede the production of ketoacids by CAFs to support cancer cells. However, in our study, we discovered a dose-dependent increase in transforming growth factor β1 (TGF-β1) levels in cancer cells in response to gabapentin. This reverse increase of TGF-β1 contributes to 'Gabapentin-resistance', leading to the antitumor effects on PDAC cell lines are negatively negotiated in the presence of pancreatic stellate cells. Pirfenidone synergistically inhibited the growth and apoptosis resistance of PDAC when combined with Gabapentin. In a mouse orthotopic PDAC model, Fe3+-mediated coordination nanodrugs, which contain gabapentin, pirfenidone and the natural polyphenol (EGCG), efficiently promoted the infiltration of naïve CD8+ T cells (CD44lowCD62Lhigh) and the accumulation of inflammatory CAFs (α-SMAlowIL-6high). This led to a nearly two-fold increase in survival compared to the control. Furthermore, we identified a new subpopulation as Hmox1highiCAFs following treatment with our nanodrugs. Hmox1highiCAFs overexpressed the Cxcl10 receptor (Sdc4) and facilitated functional CD8+ T-cell infiltration through the Tnfsf9-Tnfrsf9 axis. Overall, our nanodrugs reshape the phenotype of CAFs and enhance functional CD8+ T-cell infiltration into tumors, holding the potential to be a safe and promising therapy for PDAC.

Inflammatory Mesenchymal Stromal Cells and IFN-responsive T cells are key mediators of human bone marrow niche remodeling in CHIP and MDS

Somatic mutations in hematopoietic stem/progenitor cells (HSPCs) can lead to clonal hematopoiesis of indeterminate potential (CHIP), potentially progressing to myelodysplastic syndromes (MDS). Here, we investigated how CHIP and MDS remodel the human bone marrow (BM) niche relative to healthy elderly donors, using single cell and anatomical analyses in a large BM cohort. We found distinct inflammatory remodeling of the BM in CHIP and MDS. Furthermore, the stromal compartment progressively lost its HSPC-supportive adipogenic CXCL12-abundant reticular cells while an inflammatory mesenchymal stroma cell (iMSCs) population emerged in CHIP, which expanded in MDS. iMSCs exhibited distinct functional signatures in CHIP and MDS, retaining residual HSPC-support and angiogenic activity in MDS, corresponding with an increase in microvasculature in the MDS niche. Additionally, an IFN-responsive T cell population was linked to fueling inflammation in the stroma. Overall, these findings open new avenues for early intervention in hematological malignancies.

CAFomics: convergence to translation for precision stroma approaches

A noticeable characteristic of pancreatic ductal adenocarcinoma (PDAC) tumors is a dense tumor microenvironment with abundant and dense, desmoplastic stroma woven tightly with both cellular and matrix components. The high stromal density is associated with higher intratumor pressures which, until the last decade, was largely assumed to be tumor protective, confirmed by early studies demonstrating that altering the stroma was effective in genetically engineered models of PDAC. However, clinical trials using these approaches have been disappointing. There is increasing recognition that stroma heterogeneity is much greater than initially thought with an explosion of investigation into cancer-associated fibroblast (CAF) subpopulations led by experimental and single-cell transcriptomic studies. This review summarizes and attempts to harmonize the current transcriptomic data of CAF subpopulations. Understanding the heterogeneity of CAFs, the matrix, and other tumor microenvironment features will be critical to developing effective therapeutic approaches. Identifying model systems that best recapitulate the clinical behavior and treatment response of human PDAC will be important. Examining subpopulations as defined by clinical outcome will remain a critical step in defining clinically impactful CAF subtypes in larger clinical cohorts. The future of precision oncology in PDAC will depend on the integration of precision tumor epithelial and precision stroma approaches.

YAP1 Inhibition Induces Phenotype Switching of Cancer-Associated Fibroblasts to Tumor Suppressive in Prostate Cancer

Prostate cancer rarely responds to immune-checkpoint blockade (ICB) therapies. Cancer-associated fibroblasts (CAF) are critical components of the immunologically "cold" tumor microenvironment and are considered a promising target to enhance the immunotherapy response. In this study, we aimed to reveal the mechanisms regulating CAF plasticity to identify potential strategies to switch CAFs from protumorigenic to antitumor phenotypes and to enhance ICB efficacy in prostate cancer. Integration of four prostate cancer single-cell RNA sequencing datasets defined protumorigenic and antitumor CAFs, and RNA-seq, flow cytometry, and a prostate cancer organoid model demonstrated the functions of two CAF subtypes. Extracellular matrix-associated CAFs (ECM-CAF) promoted collagen deposition and cancer cell progression, and lymphocyte-associated CAFs (Lym-CAF) exhibited an antitumor phenotype and induced the infiltration and activation of CD8+ T cells. YAP1 activity regulated the ECM-CAF phenotype, and YAP1 silencing promoted switching to Lym-CAFs. NF-κB p65 was the core transcription factor in the Lym-CAF subset, and YAP1 inhibited nuclear translocation of p65. Selective depletion of YAP1 in ECM-CAFs in vivo promoted CD8+ T-cell infiltration and activation and enhanced the therapeutic effects of anti-PD-1 treatment on prostate cancer. Overall, this study revealed a mechanism regulating CAF identity in prostate cancer and highlighted a therapeutic strategy for altering the CAF subtype to suppress tumor growth and increase sensitivity to ICB. Significance: YAP1 regulates cancer-associated fibroblast phenotypes and can be targeted to switch cancer-associated fibroblasts from a protumorigenic subtype that promotes extracellular matrix deposition to a tumor-suppressive subtype that stimulates antitumor immunity and immunotherapy efficacy.

Mapping and tracing Grem1+ stromal cells in an Apc Min/+ mouse utilizing cryopreserved intestinal sections prepared via modified Swiss-roll technique

Grem1+ cancer-associated fibroblasts (CAFs) are crucial in colorectal cancer (CRC) development, yet technical challenges have limited understanding of their origins, spatiotemporal distribution, and potential roles. Here, we devised a custom mold, optimizing the gut Swiss-roll technique to create a single cryopreserved slide for comprehensive staining. Our integrated approach uncovered a marked increase in Grem1+ CAFs within Apc Min/+ mouse tumors at 12 weeks, compared to normal mucosa. Subsequent lineage tracing in Grem1-CreER T2 ; R26-LSL-tdTomato; Apc Min/+ mice revealed that most Grem1+ CAFs infiltrating the tumor core originated from Grem1+ intestinal reticular stem cells (iRSCs). A minor subset of Grem1+ CAFs, located in the submucosa, retained characteristics of Grem1+ intestinal sub-epithelial myofibroblasts (ISEMFs). Altogether, CAFs derived from Grem1+ iRSCs may serve as a principal stromal cell type driving early-stage CRC progression, while Grem1+ ISEMFs contribute less from a more distant location. Hence, targeting Grem1+ CAFs presents an early and promising therapeutic strategy in CRC.

Cancer-associated fibroblasts barrier breaking via TGF-β blockade paved way for docetaxel micelles delivery to treat pancreatic cancer

TGF-β is a crucial regulator in tumor microenvironment (TME), especially for myofibroblastic cancer-associated fibroblasts (myCAFs). The myCAFs can be motivated by TGF-β signaling to erect pro-tumor TME, meanwhile, myCAFs overexpress TGF-β to mediate the crosstalk between tumor and stromal cells. The blockade of TGF-β can break cancer-associated fibroblasts barrier, consequently opening the access for drugs into tumor. The TGF-β is a promising target in anti-tumor therapy. Herein, we introduced a two-stage combination therapy (TC-Therapy), including TGF-β receptor I inhibitor SB525334 (SB) and cytotoxicity agent docetaxel micelle (DTX-M). We found that SB and DTX-M synergistically inhibited myCAFs proliferation and elevated p53 protein expression in BxPC-3/3T3 mixed cells. Gene and protein tests demonstrated that SB cut off TGF-β signaling via receptor blockade and it did not arouse TGF-β legend compensated internal autocrine. On the contrary, two agents combined decreased TGF-β secretion and inhibited myCAFs viability marked by α-SMA and FAPα. TC-Therapy was applied in BxPc-3/3T3 mixed tumor-bearing mice model. After TC-Therapy, the α-SMA+/ FAPα+ myCAFs faded increasingly and collagenous fibers mainly secreted by myCAFs decreased dramatically as well. More than that, the myCAFs barrier breaking helped to normalize micro-vessels and paved way for micelle penetration. The TGF-β protein level of TC-Therapy in TME was much lower than that of simplex DTX-M, which might account for TME restoration. In conclusion, TGF-β inhibitor acted as the pioneer before nano chemotherapeutic agents. The TC-Therapy of TGF-β signaling inhibition and anti-tumor agent DTX-M is a promising regimen without arising metastasis risk to treat pancreatic cancer. The therapeutic regimen focused on TGF-β related myCAFs reminds clinicians to have a comprehensive understanding of pancreatic cancer.

TAK1 Promotes an Immunosuppressive Tumor Microenvironment through Cancer-Associated Fibroblast Phenotypic Conversion in Pancreatic Ductal Adenocarcinoma

PURPOSE

We aim to clarify the precise function of TGFβ1-activated kinase 1 (TAK1) in cancer-associated fibroblasts (CAF) within human pancreatic ductal adenocarcinoma (PDAC) by investigating its role in cytokine-mediated signaling pathways.

EXPERIMENTAL DESIGN

The expression of TAK1 in pancreatic cancer was confirmed by The Cancer Genome Atlas data and human pancreatic cancer specimens. CAFs from freshly resected PDAC specimens were cultured and used in a three-dimensional model for direct and indirect coculture with PDAC tumors to investigate TAK1 function. Additionally, organoids from [LSL-KrasG12D/+, LSL-Trp53R172H/+, Pdx1-Cre (KPC)] mice were mixed with CAFs and injected subcutaneously into C57BL/6 mice to explore in vivo functional interactions of TAK1.

RESULTS

The Cancer Genome Atlas data revealed significant upregulation of TAK1 in PDAC, associating with a positive correlation with the T-cell exhaustion signature. Knockdown of TAK1 in CAFs decreased the inflammatory CAF signature and increased the myofibroblastic CAF signature both in vitro and in vivo. The absence of TAK1 hindered CAF proliferation, blocked several inflammatory factors via multiple pathways associated with immunosuppression, and hindered epithelial-mesenchymal transition and outgrowth in vitro in spheroid cocultures with PDAC cells. Additionally, TAK1 inhibitor restrained tumor growth, increased CD4+ and CD8+ T-cell abundance, and reduced immunosuppressive cells present in vivo.

CONCLUSIONS

Blocking the TAK1+ CAF phenotype leads to the conversion of protumorigenic CAFs to antitumorigenic CAFs. This highlights TAK1 as a potential therapeutic target, particularly in CAFs, and represents a novel avenue for combined immunotherapy in PDAC.

SpottedPy quantifies relationships between spatial transcriptomic hotspots and uncovers environmental cues of epithelial-mesenchymal plasticity in breast cancer

Spatial transcriptomics is revolutionizing the exploration of intratissue heterogeneity in cancer, yet capturing cellular niches and their spatial relationships remains challenging. We introduce SpottedPy, a Python package designed to identify tumor hotspots and map spatial interactions within the cancer ecosystem. Using SpottedPy, we examine epithelial-mesenchymal plasticity in breast cancer and highlight stable niches associated with angiogenic and hypoxic regions, shielded by CAFs and macrophages. Hybrid and mesenchymal hotspot distribution follows transformation gradients reflecting progressive immunosuppression. Our method offers flexibility to explore spatial relationships at different scales, from immediate neighbors to broader tissue modules, providing new insights into tumor microenvironment dynamics.

The Mechanism by Which Hedgehog Interacting Protein (HHIP) in Cancer-Associated Fibroblasts Regulate the Secretion of Inflammatory Factors Through the JAK1/STAT3 Pathway Affecting Prostate Cancer Stemness

Purpose

Prostate cancer (PCa) is seriously affecting men's health and quality of life. Existing studies indicate that PCa stem cells are responsible for promoting the growth and contributing to the high recurrence rate of PCa.

Methods

We retrieved and downloaded PCa-related datasets from both the GEO and TCGA database. These datasets were subsequently analyzed using single-cell analysis, difference analysis, WGCNA, and machine learning algorithms. WB was performed to detect the expression of Hedgehog interacting protein (HHIP), JAK1/STAT3 pathway-related protein, CD133 and CD44. Immunohistochemistry was conducted to assess the distribution of HHIP and Ki67. The levels of inflammatory factors were measured using ELISA. The tumor cell stemness was evaluated through spheroid formation assay and flow cytometry.

Results

Through bioinformatics analysis, we identified eight genes (ARHGAP24, HHIP, MITF, CBX7, PPP1R12B, PLEKHA1, ADGRA2, and PGR). Among these genes, we selected HHIP for follow-up experiments and confirmed its low expression in PCa tumor tissues. Primary cancer-associated fibroblasts (CAFs) were extracted, and to further explore the mechanism of HHIP, we overexpressed or knocked down HHIP in CAFs. Overexpression of HHIP was found to inhibit the JAK1/STAT3 pathway and the secretion of inflammatory factors, thus suppressing both the proliferation and stemness of PCa cells. Treatment of CAFs with the JAK1/STAT3 pathway inhibitor AG490 led to a decrease in inflammatory factor secretion, along with inhibition of PCa cell proliferation and stemness. On this basis, knockdown of HHIP partially reversed the inhibitory effects of AG490 on PCa cells. Finally, we constructed a mouse subcutaneous tumor model and found that HHIP inhibited tumor proliferation and densification.

Conclusion

In summary, HHIP in CAFs can regulate the JAK1/STAT3 pathway and affect the secretion of inflammatory factors, thus affecting the proliferation of PCa.

Understanding and measuring mechanical signals in the tumor stroma

The tumor microenvironment (TME) is well known for its immune suppressive role, especially in solid tumors which are characterized by a thick, dense stroma. Apart from cell-cell interactions and biochemical signals, the tumor stroma is also characterized by its distinct mechanical properties, which are dictated by the composition and architecture of its extracellular matrix (ECM). Cancer-associated fibroblasts (CAFs) are the main producers and remodelers of the stromal ECM, and their heterogeneity has recently become a focus of intense research. This review describes recent findings highlighting CAF subtypes and their specific functions, as well as the development of 3D models to study tumor stroma mechanics in vitro. Finally, we discuss the quantitative techniques used to measure tissue mechanical properties at different scales. Given the diagnostic and prognostic value of stroma stiffness and composition, and the recent development of anti-tumor therapeutic strategies targeting the stroma, understanding and measuring tumor stroma mechanical properties has never been more timely or relevant.

Targeting heterogeneous tumor microenvironments in pancreatic cancer mouse models of metastasis by TGF-β depletion

The dual tumor-suppressive and -promoting functions of TGF-β signaling has made its targeting challenging. We examined the effects of TGF-β depletion by AVID200/BMS-986416 (TGF-β-TRAP), a TGF-β ligand trap, on the tumor microenvironment of pancreatic ductal adenocarcinoma (PDAC) murine models with different organ-specific metastasis. Our study demonstrated that TGF-β-TRAP potentiates the efficacy of anti-programmed cell death 1 (anti-PD-1) in a PDAC orthotopic murine model with liver metastasis tropism, significantly reducing liver metastases. We further demonstrated the heterogeneous response of cytotoxic effector T cells to combination TGF-β-TRAP and anti-PD-1 treatment across several tumor models. Single-nuclear RNA sequencing suggested that TGF-β-TRAP modulates cancer-associated fibroblast (CAF) heterogeneity and suppresses neutrophil degranulation and CD4+ T cell response to neutrophil degranulation. Ligand-receptor analysis indicated that TGF-β-TRAP may modulate the CCL5/CCR5 axis as well as costimulatory and checkpoint signaling from CAFs and myeloid cells. Notably, the most highly expressed ligands of CCR5 shifted from the immunosuppressive CCL5 to CCL7 and CCL8, which may mediate the immune agonist activity of CCR5 following TGF-β-TRAP and anti-PD-1 combination treatment. This study suggested that TGF-β depletion modulates CAF heterogeneity and potentially reprograms CAFs and myeloid cells into antitumor immune agonists in PDAC, supporting the validation of such effects in human specimens.

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.