Pancreatic ductal adenocarcinoma (PDAC) remains one of the most deadly malignancies with a highly immunosuppressive tumor immune microenvironment (TIME) that hinders effective therapy. PDAC is characterized by significant heterogeneity in immune cell composition, spatial distribution and activation states, which impacts tumor progression and treatment response. Tumour-infiltrating lymphocytes (TILs), including CD4+ T-helper cells, CD8+ cytotoxic T-cells and FOXP3+ regulatory T-cells, play a key role in immune regulation, yet PDAC is largely an immunologically "cold" tumour with limited effector T-cell infiltration. The surrounding cellular microenvironment, particularly Cancer Associated Fibroblasts (CAFs) and macrophages, contributes to immune evasion by promoting a fibrotic and desmoplastic barrier that limits TIL infiltration. The prognostic significance of TILs is increasingly recognized, with higher densities correlating with improved survival, whereas regulatory T-cell infiltration and immunosuppressive stromal interactions are associated with poor outcomes. Emerging therapeutic strategies targeting the TIME (e.g., CAFs), immune checkpoint inhibitors, and TIL-based therapies offer the potential to overcome resistance. Future research must focus on optimizing immunotherapy strategies and unravelling the complex stromal-immune interactions to improve clinical translation.

Pancreatic cancer is one of the most malignant tumors with a grim prognosis. Patients develop chemoresistance that drastically decreases their survival. The chemoresistance is mainly attributed to deficient vascularization of the tumor, intratumoral heterogeneity and pathophysiological barrier due to the highly desmoplastic tumor microenvironment. The interactions of cells that constitute the tumor microenvironment change its architecture into a cancer-permissive environment and stimulate cancer development, metastasis and treatment response. The cell-cell communication in the tumor microenvironment is often mediated by exosomes that harbour a diverse repertoire of molecular cargo, such as proteins, lipids, and nucleic acid, including messenger RNAs, non-coding RNAs and DNA. Therefore, exosomes can serve as potential targets as biomarkers and improve the clinical management of pancreatic cancer to overcome chemoresistance. This review critically elucidates the role of exosomes in cell-cell communication within the tumor microenvironment and how these interactions can orchestrate chemoresistance.

Immunotherapy has emerged as a standard treatment option for multiple solid tumors. However, most patients with pancreatic cancer (PC) do not derive a significant benefit. Identification and analyses of exceptional responders could eventually offer hints as to why PC is resistant to immunotherapy.

Oncologists from cancer centers in the United States were contacted to identify patients with PC who responded to immunotherapy. Exceptional responders were defined as those having either partial (PR) or complete response (CR) based on Response Evaluation Criteria in Solid Tumors, or biochemical response (CA 19-9 levels) after starting immunotherapy. Patients receiving concurrent chemotherapy were excluded.

14 patients met inclusion criteria. Immunotherapy drugs included checkpoint inhibitors and macrophage inhibitors. Eight patients (42%) were MSI (microsatellite instability)-high. Radiologically, 82% had PR. Four patients (28%) had marked reduction in CA 19-9. The median progression-free survival was 12 months from the start of immunotherapy. Median survival was not reached. The 1- and 2-year survival probabilities were 80%, 70% respectively.

Majority of clinical trials evaluating immunotherapy in PC have yielded disappointing response rates compared to other solid tumors. Our case series adds to published data from early-phase trials supporting the promise of immunotherapy in some patients with PC.

Cancer-associated fibroblasts (CAFs), the predominant stromal cells in the tumor microenvironment (TME), play a critical role in the progression of solid tumors, including oral squamous cell carcinoma (OSCC). However, the molecular mechanisms by which OSCC-derived factors mediate CAF differentiation remain incompletely understood. This study investigates the role of the C-X-C motif chemokine ligand 1 (CXCL1), secreted by OSCC cells, in promoting CAF differentiation and its downstream impact on tumor progression. Gingival fibroblasts (GFs) were treated with conditioned medium (CM) from various OSCC cell lines to assess their potential to induce CAF differentiation. Proteomic analysis using liquid chromatography-mass spectrometry identified CXCL1 as a key factor highly secreted in SCC25-derived CM, which exhibited the strongest capacity to induce CAF differentiation. CXCL1 synergistically enhanced TGF-β1-induced differentiation of GFs into α-smooth muscle actin (αSMA)- and vimentin-expressing CAFs by approximately 1.5-fold, confirming its co-stimulatory function. Conversely, silencing its receptor CXCR2 reduced CAF marker expression by over 50%, indicating a strong inhibitory effect on CAF differentiation. In vivo, co-injection of SCC25 cells with GFs significantly promoted tumor growth and stromal CAF marker expression, whereas CXCR2 knockdown in GFs led to a ~ 40% reduction in tumor volume and reduced αSMA/vimentin-positive CAFs. These findings establish CXCL1 as a pivotal mediator of CAF differentiation through CXCR2-dependent signaling, and highlight that the CXCL1-CXCR2 axis is a promising therapeutic target for modulating stromal-tumor interactions in OSCC.

Existing single-cell clustering methods are based on gene expressions that are susceptible to dropout events in single-cell RNA sequencing (scRNA-seq) data. To overcome this limitation, we proposed a pathway-based clustering method for single cells (scPathClus). scPathClus first transforms the single-cell gene expression matrix into a pathway enrichment matrix and generates its latent feature matrix. Based on the latent feature matrix, scPathClus clusters single cells using the method of community detection. Applying scPathClus to pancreatic ductal adenocarcinoma (PDAC) scRNA-seq datasets, we identified two types of cancer-associated fibroblasts (CAFs), termed csCAFs and gapCAFs, which highly expressed complement system and gap junction-related pathways, respectively. Spatial transcriptome analysis revealed that gapCAFs and csCAFs are located at cancer and non-cancer regions, respectively. Pseudotime analysis suggested a potential differentiation trajectory from csCAFs to gapCAFs. Bulk transcriptome analysis showed that gapCAFs-enriched tumors are more endowed with tumor-promoting characteristics and worse clinical outcomes, while csCAFs-enriched tumors confront stronger antitumor immune responses. Compared to established CAF subtyping methods, this method displays better prognostic relevance.

Fibroinflammation refers to the highly integrated fibrogenic and inflammatory responses mediated by the concerted function of fibroblasts and innate immune cells in response to tissue perturbation. This process underlies the desmoplastic remodelling of the tumour microenvironment and thus plays an important role in tumour initiation, growth and metastasis. More specifically, fibroinflammation alters the biochemical and biomechanical signalling in malignant cells to promote their proliferation and survival and further supports an immunosuppressive microenvironment by polarizing the immune status of tumours. Additionally, the presence of fibroinflammation is often associated with therapeutic resistance. As such, there is increasing interest in targeting this process to normalize the tumour microenvironment and thus enhance the treatment of solid tumours. Herein, we review advances made in unravelling the complexity of cancer-associated fibroinflammation that can inform the rational design of therapies targeting this.

Pancreatic cancer is one of the most deadly with poor prognosis and overall survival rate due to the dense stroma in the tumors which often is challenging for the delivery of drug to penetrate deep inside the tumor bed and usually results in the progression of cancer. The conventional treatment such as chemotherapy, radiotherapy or surgery shows a minimal benefit in the survival due to the drug resistance, poor penetration, less radiosensitivity or recurrence of tumor. There is an urgent demand to develop molecular-level targeted therapies to achieve therapeutic efficacy in the pancreatic ductal adenocarcinoma (PDAC) patients. The precision oncology focuses on the unique attributes of the patient such as epigenome, proteome, genome, microbiome, lifestyle and diet habits which contributes to promote oncogenesis. The targeted therapy helps to target the mutated proteins responsible for controlling growth, division and metastasis of tumor in the cancer cells. It is very important to consider all the attributes of the patient to provide the suitable personalized treatment to avoid any severe side effects. In this review, we have laid emphasis on the precision medicine; the utmost priority is to improve the survival of cancer patients by targeting molecular mutations through transmembrane proteins, inhibitors, signaling pathways, immunotherapy, gene therapy or the use of nanocarriers for the delivery at the tumor site. It will become beneficial therapeutic window to be considered for the advanced stage pancreatic cancer patients to prolong their survival rate.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a unique tumor microenvironment (TME) that plays pivotal roles in cancer progression, angiogenesis, metastasis, and drug resistance. This complex and dynamic ecosystem comprises cancer cells, stromal cells, and extracellular matrix (ECM) components, which interact synergistically to drive cancer aggressiveness. Among the stromal cells, cancer-associated fibroblasts (CAFs) and pancreatic stellate cells (PSCs), mainly accepted as a group of CAFs, are central players in shaping the desmoplastic, hypoxic, and immunosuppressive stroma of PDAC. PSCs, the most abundant stromal cells in PDAC, are resident pancreatic cells that undergo phenotypic changes upon activation, driving tumor progression through the secretion of cytokines, growth factors, ECM components (e.g., collagen, hyaluronic acid, fibronectin), and matrix metalloproteinases. In addition to cellular elements, ECM components significantly contribute to cancer aggressiveness by forming a physical barrier that hinders drug penetration, activating signaling pathways through specific receptor interactions, and generating peptides originating from the fragmentation of proteins to induce cancer migration. Regarding their critical roles in tumor progression, therapeutic approaches targeting PSCs and the ECM have garnered increasing interest in recent years. However, PSCs and stromal components may exhibit dual roles, with the potential to both promote and suppress tumor progression under different conditions. Therefore, targeting PSCs or stroma may lead to unintended outcomes, including exacerbation of cancer aggressiveness.

This review focuses on the multifaceted roles of PSCs in PDAC, particularly their interactions with cancer cells and their contributions to therapy resistance. Additionally, we discuss current and emerging therapeutic strategies targeting PSCs and the ECM components, including both preclinical and clinical efforts.

By synthesizing insights from recent literature, this review provides a comprehensive understanding of the role of PSCs in PDAC pathobiology and highlights potential therapeutic approaches targeting PSCs or ECM components to improve patient outcomes.

Chimeric antigen receptor (CAR) T cell therapy has revolutionized the treatment of haematological malignancies. Challenges in overcoming physical barriers however greatly limit CAR-T cell efficacy in solid tumours. Here we show that an approach based on collagenase nanogel generally improves the outcome of T cell-based therapies, and specifically of CAR-T cell therapy. The nanogels are created by cross-linking collagenase and subsequently modifying them with a CXCR4 antagonist peptide. These nanogels can bind CAR-T cells via receptor-ligand interaction, resulting in cellular backpack delivery systems. The nanogel backpacks modulate tumoural infiltration and localization of CAR-T cells by surmounting physical barriers and disrupting chemokine-mediated CAR-T cell imprisonment, thereby addressing their navigation deficiency within solid tumours. Our approach offers a promising strategy for pancreatic cancer therapy and holds potential for advancing CAR-T cell therapy towards clinical applications.

Pancreatic cancer is characterized by late diagnosis, therapy resistance, and poor prognosis, necessitating the exploration of early carcinogenesis and prevention methods. Preclinical mouse models have evolved from cell line-based to human tumor tissue- or organoid-derived xenografts, now to humanized mouse models and genetically engineered mouse models (GEMMs). GEMMs, primarily driven by oncogenic Kras mutations and tumor suppressor gene alterations, offer a realistic platform for investigating pancreatic cancer initiation, progression, and metastasis. The incorporation of inducible somatic mutations and CRISPR-Cas9 screening methods has expanded their utility. To better recapitulate tumor initiation triggered by inflammatory cues, common pancreatic risk factors are being integrated into model designs. This approach aims to decipher the role of environmental factors as secondary or parallel triggers of tumor initiation alongside oncogenic burdens. Emerging models exploring pancreatitis, obesity, diabetes, and other risk factors offer significant translational potential. This review describes current mouse models for studying pancreatic carcinogenesis, their combination with inflammatory factors, and their utility in evaluating pathogenesis, providing guidance for selecting the most suitable models for pancreatic cancer research.

The tumor microenvironment (TME) plays a crucial role in cancer development and spreading being considered as "the dark side of the tumor". Within this term tumor cells, immune components, supporting cells, extracellular matrix and a myriad of bioactive molecules that synergistically promote tumor development and therapeutic resistance, are included. Recent findings revealed the profound impacts of TME on cancer development, serving as physical support, critical mediator and biodynamic matrix in cancer evolution, immune modulation, and treatment outcomes. TME targeting strategies built on vasculature, immune checkpoints, and immuno-cell therapies, have paved the way for revolutionary clinical interventions. On this basis, the relevance of pre-clinical and clinical investigations has rapidly become fundamental for implementing novel therapeutical strategies breaking cell-cell and cell -mediators' interactions between TME components and tumor cells. This review summarizes the key players in the breast and pancreatic TME, elucidating the intricate interactions among cancer cells and their essential role for cancer progression and therapeutic resistance. Different tumors such breast and pancreatic cancer have both different and similar stroma features, that might affect therapeutic strategies. Therefore, this review aims to comprehensively evaluate recent findings for refining breast and pancreatic cancer therapies and improve patient prognoses by exploiting the TME's complexity in the next future.

Pancreatic cancer (PC), with pancreatic ductal adenocarcinoma (PDAC) comprising about 90% of all cases, is one of the most aggressive and lethal solid tumors. PDAC remains one of the most significant challenges of oncology to this day due to its inadequate response to conventional treatment, gradual rise in incidence since 2004, and poor five-year survival rates. As cancer cells are the primary adversary in this uneven fight, they remain the primary research target. Nevertheless, increasing attention is being paid to the tumor microenvironment (TME). The most crucial TME constellation components are immune cells, especially macrophages, stellate cells and lymphocytes, fibroblasts, bacterial and fungal microflora, and neuronal cells. Depending on the particular phenotype of these cells, the composition of the microenvironment, and the cell ratio, patients can experience different disease outcomes and varying vulnerability to treatment approaches. This study aims to present the current knowledge and review the most up-to-date scientific findings regarding the microenvironment of PC. It contains detailed information on the structure and cellular composition of the stroma, including its impact on disease development, metastasis, and response to treatment, as well as the therapeutic opportunities that arise from targeting this tissue.

The stroma of healthy pancreases contains various non-hematopoietic, non-endothelial mesenchymal cells. It is altered by chronic inflammation which in turn is a major contributor to the development of pancreatic adenocarcinoma (PDAC). In PDAC, the stroma plays a decisive and well-investigated role for tumor progression and therapy response. This review addresses the central role of stromal cells in the early inflammation-driven development of PDAC. It focuses on major subpopulations of pancreatic mesenchymal cells, i.e., fibroblasts, pancreatic stellate cells, and multipotent stroma cells, particularly their activation and functional alterations upon chronic inflammation including the development of different types of carcinoma-associated fibroblasts. In the second part, the current knowledge on the impact of activated stroma cells on acinar-to-ductal metaplasia and the transition to pancreatic intraepithelial neoplasia is summarized. Finally, putative strategies to target stroma cells and their signaling in early pancreatic carcinogenesis are reflected. In summary, the current data show that the activation of pancreatic stroma cells and the resulting fibrotic changes has pro- and anti-carcinogenetic effects but, overall, creates a carcinogenesis-promoting microenvironment. However, this is a dynamic process and the therapeutic targeting of specific pathways and cells requires in-depth knowledge of the molecular interplay of various cell types.

Cancer associated fibroblasts (CAFs) play a critically important role in facilitating tumour cell invasion during metastasis. They also modulate local biophysical features of the tumour microenvironment through the formation of fibrotic foci, which have been correlated with breast cancer aggression. However, the impact of the evolving three-dimensional biophysical tumour microenvironment on CAF function remains undefined. Here, by isolating CAFs from primary human triple-negative breast cancer tissue at the time of surgery, we find that their ability to remodel the local microenvironment and invade into a three-dimensional matrix correlates with disease state. We then engineered culture models to systematically deconstruct and recreate mechanical tissue features of early breast cancer fibrotic foci; and demonstrate that invasion is mechanically-activated only in CAFs from patients with no detectable pre-existing metastases, but is independent of mechanical cues in CAFs isolated from patients with later-stage axillary lymph node metastases. By comparing the differential transcriptional response of these cells to microenvironmental tissue stiffness, we identify the aryl hydrocarbon receptor (AhR) as being significantly upregulated in invasive sub-populations of both mechanically-activated and mechanically-insensitive CAFs. Increasing AhR expression in CAFs induced invasion, while suppressing AhR significantly reduced invasion in both mechanically-activated and mechanically-insensitive CAF populations, even on stiffnesses that recapitulate late-stage disease. This work therefore uses mechanobiological analyses to identify AhR as a mediator of CAF invasion, providing a potential stratification marker to identify those patients who might respond to future mechanics-based prophylactic therapies, and provides a targetable mechanism to limit CAF-associated metastatic disease progression in triple-negative breast cancer patients. STATEMENT OF SIGNIFICANCE: By designing a mechanically-tunable tissue-engineered model of fibroblastic foci, and using this to culture patient-derived cancer-associated fibroblasts, we demonstrate that these cells are differentially mechanosensitive, depending on disease stage of the patient. While comparing transcriptomic profiles of patient-derived cells produces too many pathways to screen, identifying the pathways activated by local tissue mechanics that were common across each patient allowed us to identify a specific target to limit fibroblast invasion. This broad discovery strategy may be useful across a variety of biomaterials-based tissue engineered models; and these specific findings suggest (1) a strategy to identify patients who might respond to CAF- or matrix-targeting therapies, and (2) a specific actionable target to limit CAF-associated metastatic disease progression.

Tumorigenesis ensues within a heterogeneous tissue microenvironment that promotes malignant transformation, metastasis and treatment resistance. A major feature of the tumor microenvironment is the heterogeneous population of cancer-associated fibroblasts and myeloid cells that stiffen the extracellular matrix. The heterogeneously stiffened extracellular matrix in turn activates cellular mechanotransduction and creates a hypoxic and metabolically hostile microenvironment. The stiffened extracellular matrix and elevated mechanosignaling also drive tumor aggression by fostering tumor cell growth, survival, and invasion, compromising antitumor immunity, expanding cancer stem cell frequency, and increasing mutational burden, which promote intratumor heterogeneity. Delineating the molecular mechanisms whereby tissue mechanics regulate these phenotypes should help to clarify the basis for tumor heterogeneity and cancer aggression and identify novel therapeutic targets that could improve patient outcome. Here, we discuss the role of the extracellular matrix in driving cancer aggression through its impact on tumor heterogeneity.

Transforming growth factor-beta (TGF-β) has long been known to be associated with early embryonic development and organogenesis, immune supervision, and tissue repair and homeostasis in adults. TGF-β has complex roles in fibrosis and cancer that may be opposing at different stages of these diseases. Under pathological conditions, overexpression of TGF-β causes epithelial-mesenchymal transition, deposition of extracellular matrix, and formation of cancer-associated fibroblasts, leading to fibrotic disease or cancer. Fibroblasts, epithelial cells, and immune cells are the most common targets of TGF-β, while fibrosis and cancer are the most common TGF-β-associated diseases. Given the critical role of TGF-β and its downstream molecules in fibrosis and progression of cancer, therapies targeting TGF-β signaling appear to be a promising strategy. Preclinical and clinical studies have investigated therapies targeting TGF-β, including antisense oligonucleotides, monoclonal antibodies, and ligand traps. However, development of targeted TGF-β therapy has been hindered by systemic cytotoxicity. This review discusses the molecular mechanisms of TGF-β signaling and highlights targeted TGF-β therapy for cancer and fibrosis as a therapeutic strategy for related diseases.

Pathological examination of lymph node metastasis (LNM) is crucial for treating pancreatic ductal adenocarcinoma (PDAC). Although the tumour stroma is correlated with prognosis in multiple solid tumors, its role in detecting LNM in PDAC is unclear. Thus, this study aimed to investigate the relationship of tumor-stroma ratio (TSR) with LNM, survival and mutational profile in PDAC.

In this multicenter retrospective study, we examined molecular and clinicopathologic features of 737 PDAC patients from 5 independent cohorts, including surgically resected and endoscopic ultrasound fine-needle aspiration (EUS-FNA) biopsy specimens. TSR was evaluated on hematoxylin and eosin-stained slides and classified as stroma-low (<50% stroma) or stroma-high (≥50% stroma).

Compared to TSR-high cases, TSR-low cases were significantly associated with LNM (P < 0.001). TSR could accurately distinguish patients with and without LNM with an area under curve (AUC) of 0.749, with the sensitivity and specificity of 76.5% and 71.6%, respectively. This accuracy of TSR for identifying LNM was further increased by adding other factors including PD-L1 expression or pretreatment serum CA19-9 levels. TSR showed similar levels of accuracy in analysis of resected tumor specimens and EUS-FNA biopsies. Moreover, we found that TSR could also identify residual nodal involvement after neoadjuvant therapy (NAT) using pretreatment EUS-FNA biopsy samples. Heterogeneous genetic alterations were observed between TSR-low and TSR-high subgroups. TSR was identified as an independent predictor of LNM and worse disease-free survival. Major findings were all reproducible in validation, EUS-FNA biopsy, and pre-treatment NAT EUS-FNA biopsy cohorts.

TSR served as a robust and reproducible biomarker that identifies patients at risk for LNM. TSR might be used to select treatment and management strategies for PDAC patients.

Osteosarcoma (OS) is a prevalent primary bone malignancy with limited treatment options. Therefore, it is imperative to investigate and understand the mechanisms underlying OS pathogenesis. Cancer-associated fibroblasts (CAFs) are markedly abundant in tumor stromal cells and are essentially involved in the modulation of tumor occurrence and development. In recent years, CAFs have become a hotspot as researchers aim to elucidate CAF mechanisms that regulate tumor progression. However, most studies on CAFs are limited to a few common cancers, and their association with OS remains elusive. This review describes the role and current knowledge of CAFs in OS, focusing on their potential cellular origin, classification, and diverse functionality. It was found that CAFs influenced OS tumor cell signaling, proliferation, invasion, metastasis, epithelial-mesenchymal transition, stemness maintenance, angiogenesis, and the ability to modify immune system components. Furthermore, findings on other common cancers indicated that effective therapeutic strategies included the manipulation of CAF activation, targeting CAF-derived components, and depletion of CAFs by biomarkers. This review provides new insights and a theoretical basis for OS research.

The tumor microenvironment (TME) 's primary constituents that promote cancer development are cancer-associated fibroblasts (CAFs). Metabolic remodeling has been shown to control CAF activity, particularly aberrant lipid metabolism. SCD1 can be thought of as the primary enzyme controlling the fluidity of lipid bilayers by gradually converting saturated fatty acids into monounsaturated fatty acids. Furthermore, its crucial function in the onset and spread of cancer is well acknowledged. Even with the increasing amount of research on changes in lipid metabolism, this problem remains a relatively understudied aspect of cancer research. Blocking several fatty acid synthesis-related enzymes highly expressed in cancerous cells inhibits cell division and encourages apoptosis. This is the situation with SCD1, whose overexpression has been linked to several changed tumors and cells. Both genetic and pharmacological silencing of SCD1 in cancer cells prevents glucose-mediated lipogenesis and tumor cell growth. However, its role in CAFs, hence, cancer biology, has been less studied. This study aimed to review the role of SCD1 in CAF biology, shedding light on their function in cancer cell biology.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most aggressive cancers, primarily due to its complex tumor microenvironment (TME), which drives both disease progression and therapy resistance. Understanding the molecular mechanisms governing TME dynamics is essential for developing new treatment strategies for this devastating disease. In this study, we uncover an oncogenic role for Galectin-1 (Gal1), a glycan-binding protein abundantly expressed by activated pancreatic stellate cells (PSCs), a key component of the PDAC TME that orchestrates tumor progression. Our findings reveal that Gal1 expression is elevated in the nucleus of human PSCs in both tissue samples and cultured cell lines. Using chromatin immunoprecipitation followed by sequencing analysis (ChIP-seq), we identify Gal1 occupancy at the promoters of several cancer-associated genes, including KRAS, a pivotal oncogene involved in PDAC pathogenesis. We demonstrate that Gal1 binds to the KRAS promoter, sustaining KRAS expression in PSCs, which, in turn, maintains PSC activation and promotes the secretion of protumorigenic cytokines. Mechanistically, Gal1 is required to preserve histone H3 lysine 4 monomethylation levels and to recruit the histone methyltransferase MLL1 to target promoters. Collectively, our findings define a nuclear function of Gal1 in modulating the transcriptional landscape of cancer-associated genes in PSCs within the PDAC TME, mediated through an epigenetic mechanism. These insights enhance our understanding of PDAC pathology and open potential avenues for therapeutic interventions targeting intracellular Gal1.

The tumor microenvironment (TME) is a highly complex and continuous evolving ecosystem, consisting of a diverse array of cellular and non-cellular components. Among these, benign non-immune cells, including cancer-associated fibroblasts (CAFs), adipocytes, endothelial cells (ECs), pericytes (PCs), Schwann cells (SCs) and others, are crucial factors for tumor development. Benign non-immune cells within the TME interact with both tumor cells and immune cells. These interactions contribute to tumor progression through both direct contact and indirect communication. Numerous studies have highlighted the role that benign non-immune cells exert on tumor progression and potential tumor-promoting mechanisms via multiple signaling pathways and factors. However, these benign non-immune cells may play different roles across cancer types. Therefore, it is important to understand the potential roles of benign non-immune cells within the TME based on tumor heterogeneity. A deep understanding allows us to develop novel cancer therapies by targeting these cells. In this review, we will introduce several types of benign non-immune cells that exert on different cancer types according to tumor heterogeneity and their roles in the TME.

Due to the highly heterogeneous and immunosuppressed tumor microenvironment (TME), pancreatic adenocarcinoma (PAAD) has limited therapeutic options and an abysmal prognosis. Ephrin A 1-5 (EFNA1-5) have been shown to regulate tumorigenesis and metastasis in various cancers, but its role in PAAD remains unclear.

We comprehensively analyzed EFNA gene expression levels in pan-cancer and PAAD using the GEPIA and HPA databases. Then, we assessed the prognostic value of EFNA1-5 using the Kaplan-Meier plotter and nomogram model. Further exploration of the association of EFNA1-5 with clinicopathological features of PAAD used information from the UALCAN database, and the TIMER dataset was used to reveal the correlation between EFNA1-5 and the tumor immune microenvironment (TIME) of pancreatic cancer. In addition, cBioPortal Databases, GSEA, and GSCALite were used to explore gene changes, protein interactions, and biological functions. Finally, the oncogenic effect of EFNA5 was verified in vivo and in vitro.

The expression levels of EFNA1-5 were significantly upregulated in PAAD. The expression of EFNA1/3/4/5 were significantly associated with overall survival (OS) and relapse-free survival (RFS) in PAAD patients. The high expression of EFNA2-5 were related to poor clinical features, such as higher tumor stage or grade and a wider range of lymph node metastasis. EFNA1-5 were closely associated with immune cell infiltration, CAFs, and MDSCs expression. Furthermore, EFNA5 is an independent risk factor for poor prognosis in PAAD patients, and it can promote the malignant progression of pancreatic cancer in vitro and in vivo.

Differential expression of EFNA1-5 is associated with TIME in pancreatic cancer, predicts different survival outcomes, and maybe a novel prognostic marker reflecting an immunosuppressive state and a potential therapeutic target.

Cancer, one of the world's deadliest diseases, is expected to claim an estimated 16 million lives by 2040. Three-dimensional (3D) models of cancer have become invaluable tools for the study of tumor biology and the development of new therapies. The tumor microenvironment (TME) is a determinant of tumor progression and has implications for clinical therapies. Cancer-associated fibroblasts (CAFs) are one of the most important components of the TME. Modeling the interactions between cancer cells and CAFs in vitro can help to create biomimetic tumor equivalents for elucidating the causes of cancer growth and assessing the effectiveness of therapies. Here, we are investigated the effect of the mutual arrangement of tumor cells and fibroblasts on the formation of tumor models and their biomimetic properties. Pancreatic tumor models of three different designs were formed by the bioprinting method. Gelatin-alginate hydrogels with and without PANC-1 (pancreatic cancer) and NIH/3 T3 (mouse fibroblasts) cells, as well as their homo- and heterospheroids, were used as bioink. To enable bioprinting, we have chosen the most suitable compositions of alginate and gelatin that provide both good printability and cell proliferation activity. We also have investigated the kinetics of spheroid formation to identify the optimal cultivation parameters for achieving spheroid sizes suitable for bioprinting. All tumor models remained viable for 3-4 weeks. At the same time, the patterns of model development in the cultivation process and the biomimetic properties of the final tissue-engineered structures depended on the model design.

In pancreatic ductal adenocarcinoma (PDAC), fibroblast activation leads to excessive secretion of extracellular matrix (ECM) and soluble factors that regulate tumor progression, prompting investigation into endoplasmic reticulum (ER)-resident proteins that may support this activation. We identified FKBP7, a peptidyl-prolyl isomerase in the ER, as overexpressed in PDAC stroma compared to cancer cells, and in patients with favorable prognosis. Analysis of single-cell RNA sequencing databases revealed FKBP7 expression in pancreatic stellate cells (PSCs) and cancer-associated fibroblasts (CAFs). When analyzed by immunohistochemistry on PDAC patient tissues, FKBP7 emerged as an early activation marker in the preneoplastic stroma, preceding αSMA expression, and responding to FAK- and TGFβ-induced stiffening and pro-fibrotic programs in PSCs. Functional analyses revealed that FKBP7 knockdown in PSCs enhanced contractility, Rho/FAK signaling, and secretion of pro-inflammatory cytokines as well as remodeling of type I collagen, promoting an activated phenotype and accelerating tumor growth in vivo. Conversely, FKBP7 expression supported a tumor-restraining (i.e. encapsulating) ECM characterized by type IV collagen. Mechanistically, FKBP7 interacts with BiP, and blocking this interaction instead leads to increased PSC secretion of type I collagen. Thus, FKBP7 serves as a novel PSC marker and ER regulator in a complex with BiP of the secretion of specific collagen subtypes, highlighting its potential to mediate ECM normalization and constrain PDAC tumorigenesis.

Pancreatic ductal adenocarcinoma (PDAC) is characterized by a complex tumor microenvironment (TME) including stromal cells that influence resistance to therapy. Recent studies have revealed that stromal cancer-associated fibroblasts (CAFs) are heterogeneous in origin, gene expression, and function. Antigen-presenting CAFs (apCAFs), are defined by major histocompatibility complex (MHC)-II expression and can activate effector CD4 + T cells that have the potential to contribute to the anti-cancer immune response, but also can induce regulatory T cell (Treg) differentiation. Whether apCAFs promote or restrain the antitumor response remains uncertain. Using tumor clones of the KPC murine PDAC model differing in sensitivity to immune checkpoint blockade (ICB), we found that immunosensitive (sKPC) tumors were characterized by higher immune cell and apCAF infiltration than resistant (rKPC) tumors. IMC analysis showed proximity of apCAFs and CD4 + T cells in both sKPC and rKPC tumors implicating interaction within the TME. apCAF-depleted sKPC tumor-bearing mice had diminished sensitivity to ICB. apCAFs from both sKPC and rKPC tumors activated tumor-infiltrating CD4 + T cells and induced Treg differentiation. However, transcriptomic analysis showed that Tregs induced by apCAFs were overexpressed for immunosuppressive genes in rKPCs relative to sKPCs, and that this is associated with differential chemokine signaling from apCAFs depending on tumor origin. Together these data implicate apCAFs as important mediators of the antitumor immune response, modulation of which could facilitate the development of more effective anti-tumor immune based approaches for PDAC patients.

Isorhamnetin (ISO), a dietary flavonoid, has been shown to possess antioxidant, anti-cancer, and anti-inflammatory properties. Cancer-associated fibroblasts (CAFs), found in the tumor microenvironment of several types of cancer including pancreatic ductal adenocarcinoma (PDAC) impact the tumor growth and development of chemoresistance. Thus, modulating CAFs is an attractive mean to increase the efficacy of therapies targeting cancer cells. In this study, the anti-proliferative effect of ISO and the underlying transcriptomic profile of ISO-treated PDAC-derived CAFs were investigated. ISO treatment showed a time- and concentration-dependent decrease in cell viability with a slight increase in apoptotic cells. Microarray and cell cycle analyses revealed ISO induced downregulation of pathways in cell cycle and DNA replication; and G2/M checkpoint. Cell cycle analysis showed cells in the G2/M phase were increased. In response to the treatment, hallmark for p53 pathway genes, known to regulate cell cycle checkpoints, were highly upregulated. Moreover, ISO-treated cells had an increased area of the mitochondrial network, but lower mitochondrial membrane potential accompanied by a decrease of ATP production, measured by oxygen consumption rate. Inflammatory gene expression of IL1A1, IL6, CXCL1, and LIF were significantly inhibited in ISO-treated CAFs. Taken together, our results demonstrated that the cytostatic effect of ISO on human CAFs was mediated by inducing cell cycle arrest at G2/M phase associated with activation of p21, impaired mitochondrial homeostasis, and inhibition of inflammatory mediators gene expression, warranting further investigation for its use in combinatorial therapy that target both the cancer and the tumor microenvironment as a whole.

Cancer-associated fibroblasts (CAFs) are key players in cancer development and therapy, and they exhibit multifaceted roles in the tumor microenvironment (TME). From their diverse cellular origins, CAFs undergo phenotypic and functional transformation upon interacting with tumor cells and their presence can adversely influence treatment outcomes and the severity of the cancer. Emerging evidence from single-cell RNA sequencing (scRNA-seq) studies have highlighted the heterogeneity and plasticity of CAFs, with subtypes identifiable through distinct gene expression profiles and functional properties. CAFs influence cancer development through multiple mechanisms, including regulation of extracellular matrix (ECM) remodeling, direct promotion of tumor growth through provision of metabolic support, promoting epithelial-mesenchymal transition (EMT) to enhance cancer invasiveness and growth, as well as stimulating cancer stem cell properties within the tumor. Moreover, CAFs can induce an immunosuppressive TME and contribute to therapeutic resistance. In this review, we summarize the fundamental knowledge and recent advances regarding CAFs, focusing on their sophisticated roles in cancer development and potential as therapeutic targets. We discuss various strategies to target CAFs, including ECM modulation, direct elimination, interruption of CAF-TME crosstalk, and CAF normalization, as approaches to developing more effective treatments. An improved understanding of the complex interplay between CAFs and TME is crucial for developing new and effective targeted therapies for cancer.

Pancreatic ductal adenocarcinoma (PDAC) is one of the most lethal cancers known to humans. However, not all patients fare equally poor survival, and a minority of patients even survives advanced disease for months or years. Thus, there is a clinical need to search corresponding prognostic biomarkers which forecast survival on an individual basis. To dig more information and identify potential biomarkers from PDAC pathological slides, we trained a deep learning (DL) model based U-net-shaped backbone. This DL model can automatically detect tumor, stroma and lymphocytes on whole slide images (WSIs) of PDAC patients. We performed an analysis of 800 PDAC scans, categorizing stroma in percentage (SIP) and lymphocytes in percentage (LIP) into two and three categories, respectively. The presented model achieved remarkable accuracy results with a total accuracy of 94.72%, a mean intersection of union rate of 78.66%, and a mean dice coefficient of 87.74%. Survival analysis revealed that SIP-mediate and LIP-high groups correlated with enhanced median overall survival (OS) across all cohorts. These findings underscore the potential of SIP and LIP as prognostic biomarkers for PDAC and highlight the utility of DL as a tool for PDAC biomarkers detecting on WSIs.

We evaluated the in vivo therapeutic efficacy and tolerability of BI-3406-mediated pharmacological inhibition of SOS1 in comparison to genetic ablation of this universal Ras-GEF in various KRAS-dependent experimental tumor settings. Contrary to the rapid lethality caused by SOS1 genetic ablation in SOS2KO mice, SOS1 pharmacological inhibition by its specific inhibitor BI-3406 did not significantly affect animal weight/viability nor cause noteworthy systemic toxicity. Allograft assays using different KRASmut cell lines showed that treatment with BI-3406 impaired RAS activation and RAS downstream signaling and decreased tumor burden and disease progression as a result of both tumor-intrinsic and -extrinsic therapeutic effects of the drug. Consistent with prior genetic evidence and the KRASmut allografts assays in immunocompromised mice, our analyses using an in vivo model of KRASG12D-driven lung adenocarcinoma (LUAD) in immunocompetent mice showed that single, systemic BI-3406 treatment impaired tumor growth and downmodulated protumorigenic components of the tumor microenvironment comparably to SOS1 genetic ablation or to treatment with the specific KRASG12D inhibitor MRTX1133. Furthermore, markedly stronger, synergistic antitumor effects were observed upon concomitant treatment with BI-3406 and MRTX1133 in the same in vivo LUAD mouse model. Our data confirm SOS1 as an actionable therapy target in RAS-dependent cancers and suggest that BI-3406 treatment may yield clinical benefit both as monotherapy or as a potential combination partner for multiple RAS-targeting strategies.

The mechanical properties of the tumor microenvironment (TME) undergo significant changes during tumor growth, primarily driven by alterations in extracellular (ECM) stiffness and tumor viscoelasticity. These mechanical changes not only promote tumor progression but also hinder therapeutic efficacy by impairing drug delivery and activating mechanotransduction pathways that regulate crucial cellular processes such as migration, proliferation, and resistance to therapy. In this review, we examine the mechanisms through which tumor cells sense and transmit mechanical signals to maintain homeostasis in the biomechanically altered TME. We explore current computational modelling strategies for mechanotransduction pathways, highlighting the need for developing models that incorporate additional components of the mechanosignaling machinery. Furthermore, we review available methods for measuring the mechanical properties of tumors in clinical settings and strategies aiming at restoring the TME and blocking deregulated mechanotransduction pathways. Finally, we propose that proper characterization and a deeper understanding of the mechanical landscape of the TME, both at the tissue and cellular levels, are essential for developing therapeutic strategies that account for the influence of mechanical forces on treatment efficacy.

Pancreatic ductal adenocarcinoma (PDAC) is marked by significant desmoplastic reactions, or the accumulation of excessive extracellular matrices. PDAC stroma has abnormally high stiffness, which alters cancer cell behaviors and creates a barrier for effective drug delivery. Unfortunately, clinical trials using a combination of chemotherapy and matrix-degrading enzyme have led to disappointing results, as the degradation of stromal tissue likely accelerated the dissemination of cancer cells. High matrix stiffness has been shown to activate cancer-associated fibroblasts (CAFs), increasing their interaction with pancreatic cancer cells (PCCs) through promoting proliferation, migration, and resistance to chemotherapy. With the advance of biomaterials science and engineering, it is now possible to design chemically defined matrices to understand the role of stiffness in activating pancreatic CAFs and how this may alter cancer cell migration. Here, we developed a norbornene-based click hydrogel system with independently tunable stiffness and cell adhesive ligand to evaluate stiffness-induced activation of CAFs and migration of PCCs. Our results show that matrix stiffness did not alter matrix deposition from CAFs but affected nuclear localization of Yes-associated protein (YAP). Our results also verify the role of CAFs on promoting PCC migration and an elevated substrate stiffness further increased PCC motility.

Alpha-fetoprotein-producing gastric or gastro-esophageal junction (AFP-G/GEJ) cancer, a rare gastric cancer subtype, exhibits increased angiogenesis and more immunosuppression than non-AFP-G/GEJ cancer. The potential benefits of anti-angiogenic agents and immunotherapy for this specific subtype remain unknown. This multi-center, single-arm, phase 2 trial (ClinicalTrials.gov NCT04609176) evaluated the antitumor activity, safety, and biomarkers of camrelizumab plus apatinib and S-1 and oxaliplatin (SOX), followed by maintenance treatment with camrelizumab plus apatinib, as a first-line treatment in patients with AFP-G/GEJ adenocarcinoma. Primary endpoint was the confirmed objective response rate (ORR) per RECIST v1.1 in the full analysis set. Secondary endpoints were disease control rate (DCR), progression-free survival (PFS), overall survival (OS), duration of response, time to response, and safety. Between December 4, 2020, and August 4, 2023, 36 patients were enrolled and treated. The trial met its primary endpoint with a confirmed ORR of 66.7% (95% CI: 49.0-81.4). The DCR was 88.9% (95% CI: 73.9-96.9). With a median follow-up of 11.7 months (range: 3.2-37.9), the median PFS reached 7.8 months (95% CI: 4.9-12.3) and the median OS reached 18.0 months (95% CI: 10.5-NR). No new safety concerns were identified. In exploratory analysis, patients with durable clinical benefit exhibited higher pre-treatment (PD-1+) CD8+ T cell densities and effective scores. First-line treatment with camrelizumab plus apatinib and SOX, followed by maintenance treatment with camrelizumab plus apatinib, is effective and safe in AFP-G/GEJ adenocarcinoma. Further studies are necessary to validate these findings.

The tumor microenvironment is a dynamic and complex three-dimensional network comprising the extracellular matrix and diverse non-cancerous cells, including fibroblasts, adipocytes, endothelial cells and various immune cells (lymphocytes T and B, NK cells, dendritic cells, monocytes/macrophages, myeloid-derived suppressor cells, and innate lymphoid cells). A constantly and rapidly growing number of studies highlight the critical role of these cells in shaping cancer survival, metastatic potential and therapy resistance. This review provides a synthesis of current knowledge on the modulating role of the cellular microenvironment in cancer progression and response to treatment.

In this ageing society, the number of patients suffering from age-related diseases, including cancer, is increasing. Cellular senescence is a cell fate that involves permanent cell cycle arrest. Accumulated senescent cells in tissues over time present senescence-associated secretory phenotype (SASP) and make the inflammatory context, disturbing the tumour microenvironment. In particular, the effect of senescent cancer-associated fibroblasts on cancer progression has recently come under the spotlight. Although scientific evidence on the impact of cellular senescence on cancer is emerging, the association between cellular senescence and cancer is heterogeneous and the comprehensive mechanism is still not revealed. Recently, a therapy targeting senescent cells, senotherapeutics, has been reported to be effective against cancer in preclinical research and even clinical trials. With further research, the development of senotherapeutics as a novel cancer therapy is expected.

Intrahepatic cholangiocarcinoma (iCCA) denotes a rare, highly malignant, and heterogeneous class of primary liver adenocarcinomas exhibiting phenotypic characteristics of cholangiocyte differentiation. Among the distinctive pathological features of iCCA, one that differentiates the most common macroscopic subtype (eg, mass-forming type) of this hepatic tumor from conventional hepatocellular carcinoma is a prominent desmoplastic reaction manifested as a dense fibro-collagenous-enriched tumor stroma. Cancer-associated fibroblasts (CAFs) represent the most abundant mesenchymal cell type in the desmoplastic reaction. Although the protumor effects of CAFs in iCCA have been increasingly recognized, more recent cell lineage tracing studies, advanced single-cell RNA sequencing, and expanded biomarker analyses have provided new awareness into their ontogeny, as well as underscored their biological complexity as reflected by the presence of multiple subtypes. In addition, evidence supports CAFs' potential to display cancer-restrictive roles, including immunosuppression. However, CAFs also play important roles in facilitating metastasis, as exemplified by lymph node metastasis and peritoneal carcinomatosis, which are common in iCCA. Herein, the authors provide a timely appraisal of the origins and phenotypic and functional complexity of CAFs in iCCA, together with providing mechanistic insights into lymphangiogenesis and peritoneal metastasis relevant to this lethal human cancer.

Genome sequencing of cancer and normal tissues, alongside single-cell transcriptomics, continues to produce findings that challenge the idea that cancer is a 'genetic disease', as posited by the somatic mutation theory (SMT). In this prevailing paradigm, tumorigenesis is caused by cancer-driving somatic mutations and clonal expansion. However, results from tumor sequencing, motivated by the genetic paradigm itself, create apparent 'paradoxes' that are not conducive to a pure SMT. But beyond genetic causation, the new results lend credence to old ideas from organismal biology. To resolve inconsistencies between the genetic paradigm of cancer and biological reality, we must complement deep sequencing with deep thinking: embrace formal theory and historicity of biological entities, and (re)consider non-genetic plasticity of cells and tissues. In this Essay, we discuss the concepts of cell state dynamics and tissue fields that emerge from the collective action of genes and of cells in their morphogenetic context, respectively, and how they help explain inconsistencies in the data in the context of SMT.

Cancer-associated fibroblasts (CAFs) are key components of the tumor microenvironment (TME). Given their various roles in tumor progression and treatment resistance, CAFs are promising therapeutic targets in cancer. The elimination of tumor-promoting CAFs has been investigated in various animal models to determine whether it effectively suppresses tumor growth. Based on recent evidence, several simple strategies have been proposed to eliminate tumor-promoting CAFs and attenuate these features. In addition, attention has focused on the critical role that CAFs play in the immunosuppressive TME. Therefore, the functional reprogramming of CAFs in combination with immune checkpoint inhibitors has also been investigated as a possible therapeutic approach. However, although potential targets in CAFs have been widely characterized, the plasticity and heterogeneity of CAFs complicate the understanding of their properties and present difficulties for clinical application. Moreover, the identification of tumor-suppressive CAFs highlights the necessity for the development of therapeutic approaches that can distinguish and switch between tumor-promoting and tumor-suppressive CAFs in an appropriate manner. In this review, we introduce the origins and diversity of CAFs, their role in cancer, and current therapeutic strategies aimed at targeting CAFs, including ongoing clinical evaluations.