Search Results (73)

Dickkopf-1 (DKK1) is a 266-amino-acid secreted glycoprotein originally identified as a high-affinity antagonist of the canonical Wnt/β-catenin signaling pathway and has emerged as a complex regulator in oncology. While historically considered as a tumor suppressor due to its ability to abrogate Wnt-driven proliferation, recent discoveries highlight a paradoxical pro-oncogenic role across various malignancies. The molecular mechanisms by which DKK1 promotes tumor progression, metastasis, and immune evasion are driven by its interaction with cell-surface receptors, specifically LRP5/6 and CKAP4. The DKK1-CKAP4 axis independently activates PI3K/AKT signaling, facilitating epithelial–mesenchymal transition (EMT), chemoresistance, and the formation of osteolytic bone lesions. Furthermore, DKK1 serves as a critical orchestrator of the tumor microenvironment (TME) by driving comprehensive immune reprogramming. It mediates the recruitment of myeloid-derived suppressor cells (MDSCs) and inactivates cytotoxic CD8⁺ T cells and natural killer (NK) cells, thereby fostering an immunosuppressive tumor microenvironment and resistance to checkpoint inhibitors. Interestingly, cancer-associated fibroblasts (CAFs) are a primary source of DKK1 in the stroma, where they facilitate immune evasion. Clinically, elevated circulating DKK1 levels correlate with advanced disease stages, increased metastatic potential, and poor overall survival in solid and hematological tumors. When used in combination with established biomarkers, serum DKK1 levels demonstrate significant utility for early detection and therapeutic monitoring. Given its intricate impact on malignancy, DKK1 has become a promising therapeutic target, with ongoing clinical trials investigating neutralizing antibodies such as DKN-01 to disrupt its oncogenic and immunosuppressive signaling. Understanding the context-dependent nature of DKK1 signaling remains essential for refining its application as both a biomarker and a component of emerging precision immunotherapy strategies. By prioritizing the literature from the last decade, this review characterizes DKK1 as a key mediator of tumor progression and immune reprogramming, while assessing its clinical potential as a biomarker and therapeutic target. Full article

Pancreatic ductal adenocarcinoma (PDAC) remains one of the deadliest solid tumours, driven by late diagnosis, early metastatic dissemination, and profound resistance to systemic therapies. Increasing evidence indicates that these hallmarks are not solely tumour cell intrinsic but are critically orchestrated by a complex and highly dynamic tumour microenvironment (TME) composed of pancreatic stellate cells (PSCs), cancer-associated fibroblast (CAF) subtypes, immune cells, endothelial and neuronal elements, and a dense extracellular matrix (ECM). This review provides an integrated overview of the cellular and acellular components of the PDAC TME and delineates how their reciprocal crosstalk drives desmoplasia, immune suppression, metabolic reprogramming, epithelial–mesenchymal transition (EMT), pre-metastatic niche formation, and metastatic outgrowth. Particular emphasis is placed on the context-dependent roles of stromal and immune niches in modulating drug delivery, chemoresistance, and failure of immunotherapy, highlighting why indiscriminate stromal depletion has yielded paradoxical outcomes. Building on these mechanistic insights, the review critically examines emerging therapeutic strategies targeting PSCs, CAF subsets, ECM components, myeloid and lymphoid populations, and key signalling pathways, including approaches that normalize stroma, reprogram immunity, or exploit nanocarrier-based delivery systems. Finally, a structured framework is proposed for rational TME-targeted combination regimens that integrate cytotoxic, targeted, and immunotherapeutic agents to overcome current therapeutic barriers in PDAC. Full article

Objective: This study aimed to identify clinically relevant regulators of pancreatic ductal adenocarcinoma (PDAC), a disease characterized by stromal remodeling and immune suppression, and to define their links to malignant progression and microenvironmental reprogramming. Methods: We integrated multi-cohort bulk, single-cell, and spatial transcriptomic datasets and subsequently validated bulk differential expression and network analyses with machine learning-based prioritization in an independent combined cohort (TCGA-PAAD plus GSE62452). Single-cell mapping was used to assess cell-type specificity, positioning candidates along inferCNV- and pseudotime-defined malignant continua. In Visium sections, a DKK1-associated program score quantified intratumoral spatial heterogeneity and informed our analyses of ligand–receptor communication. Bulk immune deconvolution linked gene levels to immune infiltration patterns, and functional assays were used to test the impact of DKK1 knockdown on migration, proliferation, clonogenic growth, and apoptosis in PDAC cells. Results: Four reproducible tumor-associated genes—DKK1, COL10A1, SULF1, and SLC24A3—were prioritized and validated externally. DKK1 was predominantly expressed by epithelial tumor cells and tracked along a malignant progression continuum. Spatially, the DKK1 program localized to epithelial-dominant regions, revealed pronounced intratumoral heterogeneity, and highlighted epithelial–endothelial and endothelial–immune signaling in high-score areas. Immune deconvolution associated higher DKK1 expression with increased myeloid infiltration and reduced cytotoxic lymphocyte signatures. Functionally, DKK1 knockdown impaired migration, proliferation, and clonogenicity while increasing apoptosis. Conclusions: We demonstrate that DKK1 is an epithelial-derived regulator linked to malignant progression and tumor–stroma–immune remodeling, supporting its potential as a biomarker and therapeutic target in PDAC treatment, including rational combinations with stroma-modulating strategies and immunotherapy. Full article

Prostate cancer (PCa) progression involves dynamic interactions between neoplastic cells and the reactive stroma (RS). Although myofibroblasts are established components of the RS, the role of other stromal populations, such as telocytes, remains poorly understood. This study investigated the presence and distribution of a telocytic stromal phenotype (CD34⁺/Vimentin⁺) in PCa across different histological grades and acinar patterns. We used digital image analysis and standardized immunohistochemistry to assess biopsy samples from 120 patients with confirmed PCa. The telocytic phenotype showed a heterogeneous distribution and was significantly enriched in high-grade tumors and specific acinar architectures, particularly Patterns B and D. In contrast, well-differentiated regions exhibited lower telocyte density, resembling non-neoplastic prostate tissue. Although the myofibroblastic phenotype (α-SMA⁺/Vimentin⁺/CD34⁻) also increased overall with tumor grade and varied across acinar patterns, this association was comparatively weaker and less statistically robust than that observed for telocytes. These results suggest that stromal remodeling encompasses a spectrum of cellular phenotypes influenced by local architectural constraints. It is proposed that telocytes serve as key mediators of tissue organization and biomechanical signaling, contributing to a feedback loop that promotes tumor progression. Combining acinar architecture with stromal phenotyping provides a refined framework for understanding epithelial–stromal co-evolution in PCa. Full article

Collagen type I has become a practical cornerstone for constructing biologically meaningful barrier interfaces in microfluidic systems. Its fibrillar architecture, native ligand display, and susceptibility to cell-mediated remodeling support epithelial and endothelial polarization, tight junctions, and transport behaviors that are difficult to achieve with purely synthetic barrier interfaces. Recent advances pair these biological strengths with tighter engineering control. For example, ultrathin collagen barriers (tens of micrometers or less) enable faster molecular exchange and short-range signaling; gentle crosslinking and composite designs limit gel compaction and delamination under flow; and patterning/bioprinting introduce alignment, graded porosity, and robust integration into device geometries. Applications now span intestine, vasculature, skin, airway, kidney, and tumor–stroma interfaces, with readouts including transepithelial/transendothelial electrical resistance (TEER), tracer permeability, and image-based quality control of fiber architecture. Persistent constraints include batch variability, long-term mechanical drift, limited standardization of fibrillogenesis conditions, and difficulties scaling fabrication without loss of bioactivity. Priorities include reporting standards for microstructure and residual crosslinker, chips for continuous monitoring, immune-competent co-cultures, and closer collaboration across materials science, microfabrication, computational modelling, and clinical pharmacology. Thus, this review synthesizes the state-of-the-art and offers practical guidance on technological readiness and future directions for using collagen type I as a biological barrier interface in biomimetic microfluidic systems. Full article

A limited period of endometrial receptivity is defined by molecular interactions between the embryo and maternal tissues, which are crucial for successful implantation. The results of clinical studies assessing intrauterine human chorionic gonadotropin (hCG) as an endometrial priming agent in in vitro fertilisation (IVF) have been inconsistent, markedly affected by dose, timing, and cycle context. This narrative review summarises molecular data demonstrating that hCG modulates immunological, stromal, endothelial, and epithelial compartments in a coordinated manner, affecting essential endometrial processes. hCG promotes adhesion competence and proliferation in the epithelium via a microRNA-regulated signalling axis (miR-126-3p–PIK3R2–PI3K/Akt). Intrauterine hCG promotes controlled apposition and invasion at the vascular interface by selectively strengthening endothelial junctional cohesion via VE-cadherin and CD146, without promoting angiogenesis. hCG collaborates with ERK/mTOR signalling to regulate autophagy and apoptosis, alters steroid–receptor networks in the stroma, initiates early decidual and survival markers (ACTA2, NOTCH1, complement C3), and enhances stress resistance. hCG modifies the immunological milieu by enhancing the activity of regulatory T cells and altering the distribution of uterine natural killer cells. This facilitates immunological tolerance and the remodelling of spiral arteries. These pleiotropic effects together enhance biomarkers and provide a scientific justification for context-dependent clinical responses, including patient-chosen, directed methods for the delivery of intrauterine hCG during IVF. Full article

Pancreatic cancer is characterized by an extensive fibrotic stroma largely driven by activated pancreatic stellate cells (PSCs)/fibroblasts, which also function to support tumor growth and metastasis. Cholecystokinin-B receptors (CCK-BRs) are expressed on pancreatic stellate cells (PSCs) and have emerged as a key regulator of PSC activation and tumor-stromal interactions. We hypothesized that disrupting CCK-BR function shifts PSCs to a more quiescent phenotype and reduces their pro-fibrotic and tumor-supportive activity to decrease growth of pancreatic cancer. Murine PSCs were genetically engineered with CRISPR-Cas9 to knockout the CCK-BR. In a series of experiments, the role of the CCK-BR expression was evaluated on cell migration, proliferation, differentially expressed genes, molecular signaling pathways, and in co-culture with murine pancreatic cancer epithelial cells. Next, primary human pancreatic stellate cells were treated with proglumide, a CCK-BR antagonist, to study the effects of pharmacologic blockade of the CCK-BR on cellular signaling and proliferative pathways by RNA sequencing. Knockout of the CCK-BR led to significant decreases in PSC activation and the ability to stimulate growth of pancreatic cancer cells in co-culture. Both genetic knockdown and pharmacologic blockade of the CCK-BR downregulated genes implicated in fibrosis, proliferation, fibroblast activation, and tumorigenesis, while genes implicated in apoptosis and tumor suppression were upregulated. Flow cytometry showed increased apoptosis markers in CCK-BR-knockout cells compared to controls. These experiments combine transcriptomic profiling with functional validation to provide a comprehensive analysis of how targeting CCK-BR interrupts the cross-communication between cancer cells and fibroblasts. Blockade or downregulation of the CCK-BR on pancreatic fibroblasts may provide a strategy to disrupt oncogenic signaling pathways and reprogram the tumor microenvironment. Full article

Background: Colorectal cancer (CRC) mortality is predominantly driven by liver metastasis and poor responsiveness to chemotherapy. The histone methyltransferase SMYD3 has been implicated in oncogenic transcriptional programs; however, its downstream effectors and microenvironmental roles in CRC remain unclear. Methods: We investigated whether SMYD3 regulates the transcription and function of the membrane receptor CDCP1, which mediates Src/PKCδ signaling and promotes invasion and stromal remodeling. A combination of molecular assays, including ChIP-qPCR, Western blotting, and co-culture experiments, was employed to examine the SMYD3–CDCP1 axis and its impact on epithelial–mesenchymal transition (EMT), cancer-associated fibroblast (CAF) activation, and oxaliplatin (OXA) sensitivity. Results: SMYD3 directly bound to the CDCP1 promoter and catalyzed H3K4me3 enrichment, thereby enhancing CDCP1 transcription. Upregulated CDCP1 activated Src/PKCδ signaling, facilitating EMT and CAF activation within the tumor microenvironment. Genetic suppression of SMYD3 reduced metastatic potential and improved oxaliplatin response in vivo, while genetic or pharmacologic perturbation attenuated tumor–stroma crosstalk and enhanced oxaliplatin sensitivity in vitro. Conclusions: The SMYD3–CDCP1 axis drives CRC progression by epigenetically promoting CDCP1 transcription and remodeling the tumor microenvironment. Targeting this pathway may provide a promising therapeutic strategy to restrain metastasis and enhance chemotherapy efficacy in CRC. Full article

Head and neck cancer (HNC) is highly heterogeneous and difficult to treat, underscoring the need for rapid, patient-specific models. Standard three-dimensional (3D) cultures often lose stromal partners that influence therapy response. We developed a patient-derived system maintaining tumor cells, cancer-associated fibroblasts (CAFs), and cells undergoing partial epithelial–mesenchymal transition (pEMT) for drug sensitivity testing. Biopsies from four HNC patients were enzymatically dissociated. CAFs were directly cultured, and their conditioned medium (CAF-CM) was collected. Cryopreserved primary tumor cell suspensions were later revived, screened in five different growth media under 2D conditions, and the most heterogeneous cultures were re-embedded in 3D hydrogels with varied gel mixtures, media, and seeding geometries. Tumoroid morphology was quantified using a perimeter-based complexity index. Viability after treatment with cisplatin or Notch modulators (RIN-1, recombination signal-binding protein for immunoglobulin κ J region (RBPJ) inhibitor; FLI-06, inhibitor) was assessed by live imaging and the water-soluble tetrazolium-8 (WST-8) assay. Endothelial Cell Growth Medium 2 (ECM-2) medium alone produced compact CAF-free spheroids, whereas ECM-2 supplemented with CAF-CM generated invasive aggregates that deposited endogenous matrix. Matrigel with this medium and single-point seeding gave the highest complexity scores. Two of the three patient tumoroids were cisplatin-sensitive, and all showed significant growth inhibition with the FLI-06 Notch inhibitor, while the RBPJ inhibitor RIN-1 induced minimal change. The optimized scaffold retains tumor–stroma crosstalk and provides patient-specific drug response data within days after operation, supporting personalized treatment selection in HNC. Full article

Cancer-associated fibroblasts (CAFs) are crucial regulators of the tumor microenvironment (TME), promoting cancer progression, immune suppression, and therapy resistance. Single-cell transcriptomics has identified at least five distinct CAF subtypes: myofibroblastic (myCAFs), inflammatory (iCAFs), antigen-presenting (apCAFs), metabolic (meCAFs), and vascular/developmental (vCAFs/dCAFs), each with unique localization, signaling, and functions. While CAFs are well studied in epithelial cancers, their roles in sarcomas are less understood despite the shared mesenchymal origin of tumor and stromal cells. This overlap blurs the line between malignant and non-malignant fibroblasts, raising fundamental questions about the identity of CAFs in mesenchymal tumors. In this narrative review, we explore the heterogeneity and plasticity of CAFs across solid tumors, focusing on their role in immune evasion, epithelial-to-mesenchymal transition (EMT), and resistance to chemotherapy, targeted therapy, and immunotherapy. We highlight emerging evidence on CAF-like cells in sarcomas and their contribution to tumor invasion, immune exclusion, and metastatic niche formation. We also assess new strategies to target or reprogram CAFs and suggest that CAF profiling may serve as a potential biomarker for patient stratification. Understanding CAF biology across various tumor types, including those with dense stroma and immunologically cold sarcomas, is crucial for developing more effective, personalized cancer treatments. Full article

The major event that leads to death from breast cancer (BrCa) is the emergence of micrometastases into lethal growing metastases. While it is still uncertain what regulates the cell fate decision between remaining in dormancy and aggressive proliferative progression, accumulating evidence demonstrates a major role for the metastatic microenvironment. One area of interest is that of tissue and circulating mesenchymal stem cells (MSCs), which have been shown to alter the proliferative and metastatic potential of BrCa. Herein, we investigate how these cells impact the phenotype of metastatic BrCa. As the disseminated BrCa cells initially adopt an epithelial phenotype in ectopic organs, one that is dormant in having limited proliferation and being immune-silent, interactions that revert the disseminated metastatic BrCa to aggressive mesenchymal phenotypes, would be a driver of metastatic progression. BrCa cells exhibited phenotypic changes including increased E-cadherin expression, altered proliferation, and differential sensitivity to TRAIL-induced apoptosis when directly co-cultured with immortalized human MSCs, compared to the BrCa cells not co-cultured. These regulatory effects were dependent upon the BrCa cell’s epithelial–mesenchymal status and involved distinct juxtacrine and paracrine signaling mechanisms, as evidenced by differing responses in direct co-culture, conditioned medium, and Transwell systems. Our findings highlight the complex and context-dependent roles of MSCs in BrCa progression, improving our understanding of tumor-stroma interactions and laying groundwork for future therapeutic exploration. Full article

Endometriosis is a disease characterized by the presence of endometrial glands and stroma outside of the uterine corpus, often clinically presenting with pain and/or infertility. Ectopic lesions exhibit features characteristic of epithelial-to-mesenchymal transition (EMT), a process in which epithelial cells lose polarity and acquire mesenchymal traits, including migratory and invasive capabilities. During the process of EMT, epithelial traits are downregulated, while mesenchymal traits are acquired, with cells developing migratory ability, increasing proliferation, and resistance to apoptosis. EMT is promoted by exposure to hypoxia and stimulation by transforming growth factor-β (TGF-β), platelet-derived growth factor (PDGF), and estradiol. Signaling pathways that promote EMT are activated in most ectopic lesions and involve transcription factors such as Snail, Slug, ZEB-1/2, and TWIST-1/2. EMT-specific molecules present in the serum of women with endometriosis appear to have diagnostic potential. Strategies targeting EMT in animal models of endometriosis have demonstrated regression of ectopic lesions, opening the door for novel therapeutic approaches. This review summarizes the current understanding of the role of EMT in endometriosis and highlights potential targets for EMT-related diagnosis and therapeutic interventions. Full article

Species have different strategies for implantation and placentation. Much can be learned about general molecular and cellular biology through the examination and comparison of these differences. To varying degrees, implantation in all species includes alterations in epithelial polarity, the transformation of the endometrial stroma, the differentiation of the trophoblast, cell-to-cell and tissue-to-tissue signaling through hormones, cytokines, and extracellular vesicles, and the alteration of the maternal immune system. This review focuses on implantation in pigs, sheep, and cows. These species share with mice/rats and humans/primates the key events of early embryonic development, pregnancy recognition, and the establishment of functional placentation. However, there are differences between the pregnancies of livestock and other species that make livestock unique biomedical models for the study of pregnancy and cell biology in general. Pig, sheep, and cow conceptuses (embryo/fetus and associated placental membranes) elongate prior to implantation, displaying central implantation, extended periods of conceptus attachment to the uterus, and epitheliochorial (pigs) and synepitheliochorial (sheep and cows) placentation. This review will discuss what is understood about how the trophoblast and extraembryonic endoderm of pig, sheep, and cow conceptuses elongate, and how a major goal of current in vitro models is to achieve conceptus elongation. It will then examine the adhesion cascade for conceptus implantation that initiates early placental development in pigs, sheep, and cows. Finally, it will conclude with a brief overview of early placental development in pigs, sheep, and cows, with a listing of some important “omics” studies that have been published. Full article

Neutrophils, accounting for 50–70% of circulating leukocytes, exhibit remarkable plasticity in tumor biology. Depending on tumor type and microenvironmental cues, they can exert either anti-tumor or pro-tumor effects. During tumor initiation, neutrophils exposed to chronic inflammation secrete cytokines and oncogenic microRNAs that promote genomic instability and malignant transformation. In tumor progression, neutrophils adopt context-dependent phenotypes and execute diverse functions, including polarization into anti-tumor (N1) or pro-tumor (N2) subsets; secretion of inflammatory and angiogenic mediators; formation of neutrophil extracellular traps (NETs); production of reactive oxygen and nitrogen species (e.g., H₂O₂ and nitric oxide); and modulation of immune cell infiltration and function within the tumor microenvironment. During metastasis, neutrophils facilitate cancer dissemination through three principal mechanisms: (1) promoting epithelial–mesenchymal transition (EMT) via inflammatory signaling, adhesion molecule interactions, and lipid metabolic support; (2) establishing pre-metastatic niches by remodeling distant organ stroma through NETs and matrix metalloproteinases; and (3) reactivating dormant tumor cells in response to chronic inflammation, viral infection, or stress hormones. Collectively, neutrophils function as central regulators across all stages of tumor evolution, influencing cancer growth, immune evasion, and metastatic progression. This review aims to provide a comprehensive synthesis of neutrophil-mediated mechanisms in the tumor microenvironment and highlight emerging strategies for neutrophil-targeted cancer therapy. Full article

Background: Colorectal cancer (CRC) heterogeneity is strongly influenced by molecular subtypes and tumor stroma interactions. The meprin/A5/PTPmu (MAM) domain, a conserved structural motif in transmembrane proteins, remains undercharacterized in CRC pathogenesis. Methods: We analyzed RNA-seq data from TCGA-COAD to evaluate MAM domain gene expression. Immunohistochemistry and Western blotting were conducted to validate the results of the database analysis. Results: Bioinformatics analysis revealed that MAM domain-containing protein 2 (MAMDC2) was enriched in mesenchymal subtype 4 (CMS4) colorectal cancer (p < 0.001). IHC confirmed MAMDC2 overexpression in MSS colorectal cancer with a high tumor stroma ratio (TSR) and peritoneal metastatic lesions (p < 0.01). WB and real-time PCR analyses confirmed that MAMDC2 has a role in regulating epithelial–mesenchymal transition (EMT) development in CRC. Importantly, we identified that cancer cell-derived MAMDC2 promotes MYLK expression in cancer-associated fibroblasts (CAFs) through paracrine signaling. Conclusions: Our findings suggest MAMDC2 may function as a stromal-associated regulator in MSS colorectal cancer with a high tumor stromal ratio (TSR). Full article