Activated fibroblasts in cancer: Perspectives and challenges

Extracellular vesicles derived from EZH2-high ovarian cancer cells facilitate omental metastasis by inducing Periostin+ fibroblasts

The frequent omental metastasis of ovarian cancer (OvCa) at initial diagnosis is due to the omental premetastatic microenvironment, which is rich in activated fibroblasts. However, the molecular events driving the phenotypic transformation of omental fibroblasts that favor metastasis remain largely unexplored. Previously, we found that tumoral enhancer of zest homolog 2 (EZH2), a key epigenetic regulator catalyzing trimethylation at H3K27, played a crucial role in OvCa metastasis. In this study, we revealed that extracellular vesicles (EVs) derived from EZH2-high OvCa cells induce the expression of Periostin (POSTN), but not α-SMA, in omental fibroblasts, facilitating tumor metastasis. Nude mice with intraperitoneal injection of EVs before tumor cell inoculation showed that EVs derived from EZH2-high ovarian cancer cells promote omental metastasis. Human primary omental fibroblasts cocultured with EVs, especially those derived from EZH2-high OvCa cells, exhibited boosted migration, invasion capacities and conditioned medium from EV-activated fibroblasts promotes cancer cell migration, invasion and proliferation. These results may provide novel insight into EZH2-targeted therapy for ovarian carcinoma with intraperitoneal dissemination.

A novel radial co-culture microfluidic device for parallel and control detection of tumor cell invasiveness

Metastasis is responsible for the majority of cancer-related deaths, and tumor cell invasion is a critical step in the cancer metastatic cascade. Traditional invasion analysis using transwell assays and immunodeficient mouse models struggles to control tumor microenvironment factors, such as various biochemical signals and cell types. A microfluidic chip system has emerged as an important tool for invasion analysis, but the simultaneous parallel and controlled experiments within the same group of tumor cells remain challenging. Here, we developed a new three-dimensional co-culture microfluidic device to investigate tumor invasion. This device consists of three concentric circles and is divided into four identical regions. Each region includes a tumor cell region, an invasion channel and a co-culture channel. Additionally, the four identical regions allow for four specific groups of parallel or control analysis surrounding the same group of tumor cells. Thus, our device enables the comparison of invasion among the same group of cells under different conditions, avoiding the discrepancies in invasion that arise when the treatment factors differ across different groups of tumor cells. Using experimental examinations and numerical simulations, we verified the capability of the device for parallel and controlled analysis of tumor invasion in response to different stimuli, including chemokines, drugs and cellular factors secreted from co-cultured cells. Furthermore, we found that in a co-culture environment with cancer-associated fibroblasts, the invasiveness of LoVo cells and their resistance to 5-fluorouracil treatment were enhanced. This innovative approach allows for easy, parallel and controlled assays to study tumor cell invasion with the advantages of multiplexing and simplicity. The method provides straightforward, repeatable control over cell-biochemical signals and cell-cell interactions, making it a valuable tool for accurately evaluating tumor invasion in metastasis studies.

Targeting the tumor microenvironment, a new therapeutic approach for prostate cancer

BACKGROUND

A growing number of studies have shown that in addition to adaptive immune cells such as CD8 + T cells and CD4 + T cells, various other cellular components within prostate cancer (PCa) tumor microenvironment (TME), mainly tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs) and myeloid-derived suppressor cells (MDSCs), have been increasingly recognized as important modulators of tumor progression and promising therapeutic targets.

OBJECTIVE

In this review, we aim to delineate the mechanisms by which TAMs, CAFs and MDSCs interact with PCa cells in the TME, summarize the therapeutic advancements targeting these cells and discuss potential new therapeutic avenues.

METHODS

We searched PubMed for relevant studies published through December 10 2023 on TAMs, CAFs and MDSCs in PCa.

RESULTS

TAMs, CAFs and MDSCs play a critical role in the tumorigenesis, progression, and metastasis of PCa. Moreover, they substantially mediate therapeutic resistance against conventional treatments including anti-androgen therapy, chemotherapy, and immunotherapy. Therapeutic interventions targeting these cellular components have demonstrated promising effects in preclinical models and several clinical trials for PCa, when administrated alone, or combined with other anti-cancer therapies. However, the lack of reliable biomarkers for patient selection and incomplete understanding of the mechanisms underlying the interactions between these cellular components and PCa cells hinder their clinical translation and utility.

CONCLUSION

New therapeutic strategies targeting TAMs, CAFs, and MDSCs in PCa hold promising prospects. Future research endeavors should focus on a more comprehensive exploration of the specific mechanisms by which these cells contribute to PCa, aiming to identify additional drug targets and conduct more clinical trials to validate the safety and efficacy of these treatment strategies.

Cancer-associated fibroblasts-derived exosomal piR-35462 promotes the progression of oral squamous cell carcinoma via FTO/Twist1 pathway

BACKGROUND

Cancer-associated fibroblasts (CAFs) represent a crucial component of tumor stroma and play critical roles in cancer progression. However, the role of CAFs derived exosomes in oral squamous cell carcinoma (OSCC) environment is unexplored. PIWI-interacting RNAs (piRNAs) serve as epigenetic effectors in cancer progression and constitute significant compositions of exosomes. Here, we explored the functional mechanism of exosomal piRNAs in OSCC development.

METHODS

We screened exosomal piRNAs derived from CAFs and normal fibroblasts (NFs) and assess their effect on tumor proliferation and metastasis. A nude mouse model was established to assess the impact of exosomal piR-35462 on tumor progression.

RESULTS

CAFs-derived exosomes showed an enhanced piR-35462 expression and promoted OSCC cell proliferation, migration and invasion. Additionally, elevated piR-35462 expression in OSCC tissues correlates with poor prognosis. Mechanistically, CAFs-derived exosomal piR-35462 increased the expression of fat mass and obesity-associated protein (FTO) in OSCC cells. By inhibiting N6-methyladenosine (m6A) RNA methylation, the overexpression of FTO further enhances the stability and expression levels of Twist1 mRNA, thereby contributing to epithelial-mesenchymal transition (EMT) and tumor progression. In vivo xenograft tumor model also confirmed the same results.

CONCLUSION

The achieved outcomes elucidate that CAFs can deliver piR-35462 containing exosomes to OSCC cells and promote OSCC progression via FTO/Twist mediated EMT pathways, and could represent a promising therapeutic target for OSCC.

Extracellular matrix: unlocking new avenues in cancer treatment

The extracellular matrix (ECM) plays a critical role in cancer progression by influencing tumor growth, invasion, and metastasis. This review explores the emerging therapeutic strategies that target the ECM as a novel approach in cancer treatment. By disrupting the structural and biochemical interactions within the tumor microenvironment, ECM-targeted therapies aim to inhibit cancer progression and overcome therapeutic resistance. We examine the current state of ECM research, focusing on key components such as collagen, laminin, fibronectin, periostin, and hyaluronic acid, and their roles in tumor biology. Additionally, we discuss the challenges associated with ECM-targeted therapies, including drug delivery, specificity, and potential side effects, while highlighting recent advancements and future directions. This review underscores the potential of ECM-focused strategies to enhance the efficacy of existing treatments and contribute to more effective cancer therapies.

FAPI PET Versus FDG PET/CT in Gastrointestinal Cancers: An Overview

Fibroblast activation protein (FAP) is a type II transmembrane serine protease that is highly expressed in cancer-associated fibroblasts (CAFs) but absent in quiescent fibroblasts. Its overexpression is associated with poor prognosis in various cancers and contributes to treatment resistance. In recent years, radiolabeled FAP inhibitors (FAPI) for PET imaging have shown promising clinical value across a range of cancers. Gastrointestinal (GI) malignancies, which often exhibit a desmoplastic reaction with a high density of FAP-expressing CAFs, are particularly well-suited for FAPI PET. Given the limitations of [18F]FDG PET in GI cancers, such as low sensitivity in certain histological subtypes and high physiological background uptake, FAPI PET is expected to serve as a complementary method, potentially enhancing both diagnostic accuracy and treatment guidance. This review provides a comprehensive comparison of the clinical applications of FAPI PET and [18F]FDG PET in various GI cancers, including their value in diagnosis, staging, and treatment guidance. Additionally, this review summarizes studies on the expanding role of FAPI PET, including its use in assessing treatment response and predicting prognosis, aiming to provide insights into its potential contribution to the improved management of GI malignancies.

The progress and prospects of targeting the adenosine pathway in cancer immunotherapy

Despite the notable success of cancer immunotherapy, its effectiveness is often limited in a significant proportion of patients, highlighting the need to explore alternative tumor immune evasion mechanisms. Adenosine, a key metabolite accumulating in hypoxic tumor regions, has emerged as a promising target in oncology. Inhibiting the adenosinergic pathway not only inhibits tumor progression but also holds potential to enhance immunotherapy outcomes. Multiple therapeutic strategies targeting this pathway are being explored, ranging from preclinical studies to clinical trials. This review examines the complex interactions between adenosine, its receptors, and the tumor microenvironment, proposing strategies to target the adenosinergic axis to boost anti-tumor immunity. It also evaluates early clinical data on pharmacological inhibitors of the adenosinergic pathway and discusses future directions for improving clinical responses.

Construction of a stromal cell-related prognostic signature based on a 101-combination machine learning framework for predicting prognosis and immunotherapy response in triple-negative breast cancer

Background

Triple-negative breast cancer (TNBC) is a highly aggressive subtype with limited therapeutic targets and poor immunotherapy outcomes. The tumor microenvironment (TME) plays a key role in cancer progression. Advances in single-cell transcriptomics have highlighted the impact of stromal cells on tumor progression, immune suppression, and immunotherapy. This study aims to identify stromal cell marker genes and develop a prognostic signature for predicting TNBC survival outcomes and immunotherapy response.

Methods

Single-cell RNA sequencing (scRNA-seq) datasets were retrieved from the Gene Expression Omnibus (GEO) database and annotated using known marker genes. Cell types preferentially distributed in TNBC were identified using odds ratios (OR). Bulk transcriptome data were analyzed using Weighted correlation network analysis (WGCNA) to identify myCAF-, VSMC-, and Pericyte-related genes (MVPRGs). A consensus MVP cell-related signature (MVPRS) was developed using 10 machine learning algorithms and 101 model combinations and validated in training and validation cohorts. Immune infiltration and immunotherapy response were assessed using CIBERSORT, ssGSEA, TIDE, IPS scores, and an independent cohort (GSE91061). FN1, a key gene in the model, was validated through qRT-PCR, immunohistochemistry, RNA interference, CCK-8 assay, apoptosis assay and wound-healing assay.

Results

In TNBC, three stromal cell subpopulations-myofibroblastic cancer-associated fibroblasts (myCAF), vascular smooth muscle cells (VSMCs), and pericytes-were enriched, exhibiting high interaction frequencies and strong associations with poor prognosis. A nine-gene prognostic model (MVPRS), developed from 23 prognostically significant genes among the 259 MVPRGs, demonstrated excellent predictive performance and was validated as an independent prognostic factor. A nomogram integrating MVPRS, age, stage, and tumor grade offered clinical utility. High-risk group showed reduced immune infiltration and increased activity in tumor-related pathways like ANGIOGENESIS and HYPOXIA, while low-risk groups responded better to immunotherapy based on TIDE and IPS scores. FN1, identified as a key oncogene, was highly expressed in TNBC tissues and cell lines, promoting proliferation and migration while inhibiting apoptosis.

Conclusion

This study reveals TNBC microenvironment heterogeneity and introduces a prognostic signature based on myCAF, VSMC, and Pericyte marker genes. MVPRS effectively predicts TNBC prognosis and immunotherapy response, providing guidance for personalized treatment. FN1 was validated as a key oncogene impacting TNBC progression and malignant phenotype, with potential as a therapeutic target.

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

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

Noninvasive prognostic classification of ITH in HCC with multi-omics insights and therapeutic implications

Intratumoral heterogeneity (ITH) is a critical factor associated with treatment failure and disease relapse in hepatocellular carcinoma (HCC). However, decoding ITH in a noninvasive and comprehensive manner remains a notable challenge. In this study involving 851 patients from five centers, we developed a noninvasive prognostic classification for ITH using radiomics based on multisequence MRI, termed radiomics ITH (RITH) phenotypes. The RITH phenotypes highly correlated with prognosis and pathological ITH. In addition, through an integrated multi-omics analysis, we uncovered the molecular mechanisms underlying RITH, notably enhancing its biological interpretability. Specifically, high-RITH tumors demonstrated an enrichment of cancer-associated fibroblasts and activation of extracellular matrix remodeling. Our approach facilitates the noninvasive refined classification of ITH using radiomics and multi-omics, paving the way for tailored treatment strategies in HCC. Extracellular matrix-receptor interaction could be a potential therapeutic target in patients with high-RITH tumors. Given the routine use of radiologic imaging in oncology, our methodology ignites versatile framework for broader application to other solid tumors.

Stromal Cells in Early Inflammation-Related Pancreatic Carcinogenesis-Biology and Its Potential Role in Therapeutic Targeting

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.

Fibroblast activation protein peptide-targeted NIR-I/II fluorescence imaging for stable and functional detection of hepatocellular carcinoma

PURPOSE

Cancer-associated fibroblasts (CAFs) are the primary stromal component of the tumor microenvironment in hepatocellular carcinoma (HCC), affecting tumor progression and post-resection recurrence. Fibroblast activation protein (FAP) is a key biomarker of CAFs. However, there is limited evidence on using FAP as a target in near-infrared (NIR) fluorescence imaging for HCC. Thus, this study aims to develop a novel NIR fluorescent imaging strategy targeting FAP+ CAFs in HCC.

METHODS

The ICG-FAP-TATA probe was synthesized by conjugating a novel cyclization anti-FAP peptide with an indocyanine green derivative (ICG-NH2) as fluorophore, capable for NIR window I (NIR-I, 700-900 nm) and II (NIR-II, 1000-1700 nm) imaging. Its efficacy in lesion localization and other potential applications was evaluated.

RESULTS

In vivo imaging of subcutaneous HCC models revealed that ICG-FAP-TATA specifically targeted FAP+ CAFs in the stroma and detected differences in CAFs loading within lesions. The fluorescence intensity/tumor-to-background ratio (TBR) positively correlated with FAP expression (R2 > 0.8, p < 0.05). Ex vivo incubation of tumor tissues with ICG-FAP-TATA provided stable fluorescence imaging of tumors in subcutaneous and orthotopic HCC models, including different cell line co-culture systems (LM3-luc, MHCC97H-luc, HepG2-luc + LX2), and various liver backgrounds (healthy/fibrotic) (n = 5 per group). TBR of the tumor mice models was higher for NIR-II than NIR-I imaging (3.89 ± 1.27 vs. 2.64 ± 0.64, p < 0.05). Moreover, NIR-I/II imaging of fresh tissues from seven patients with HCC undergoing surgery incubated with ICG-FAP-TATA visually provided the spatial distribution heterogeneity of CAFs. The targeted fluorescence was relatively enriched more in the blood flow direction and at the tumor edge, both of which were associated with tumor metastasis (all p < 0.05).

CONCLUSION

This study presents a rapid and effective method for detecting HCC lesions, locating FAP+ CAFs, and visualizing high-risk areas for tumor metastasis at the macroscopic level. It offers a new promising approach with translational potential for imaging HCC.

Macrophages and fibroblasts as regulators of the immune response in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the few cancers that has yet to benefit from immunotherapies. This is primarily a result of its characteristic 'cold' tumor microenvironment composed of cancer-associated fibroblasts (CAFs), a dense network of extracellular matrix and several immune cell types, the most abundant of which are the tumor-associated macrophages (TAMs). Advances in single-cell and spatial technologies have elucidated the vast functional heterogeneity of CAFs and TAMs, their symbiotic relationship and their cooperative role in the tumor microenvironment. In this Review, we provide an overview of the heterogeneity of CAFs and TAMs, how they establish an immunosuppressive microenvironment and their collaboration in the remodeling of the extracellular matrix. Finally, we examine why the impact of immunotherapy in PDAC has been limited and how a detailed molecular and spatial understanding of the combined role of CAFs and TAMs is paramount to the design of effective therapies.

Characterization of cancer-associated fibroblasts and their spatial architecture reveals heterogeneity and survival associations in classic Hodgkin lymphoma

Cancer-associated fibroblasts (CAFs) are a heterogeneous population of stromal cells, which modulate the immune system and can have both pro- and anti-tumorigenic effects. In classic Hodgkin lymphoma (cHL), the role of CAFs has remained largely undefined. We applied multiplexed immunofluorescence imaging and spatial analysis on tumor samples from two independent cHL patient cohorts (n = 131 and n = 148) to study CAFs and their interactions with Hodgkin Reed-Sternberg (HRS) and tumor microenvironment (TME) cells at the single-cell resolution. We show that higher proportions of CAFs are associated with favorable outcomes, independent of the clinical covariables. In contrast, a subset of CD45+ immune cells with strong fibroblast-activation protein positivity, classified as macrophages, was less abundant in nodular sclerosis subtype and associated with worse outcomes. Neighborhood analysis allowed for the identification of colocalization or regional exclusion of phenotypically defined cell types and recurrent cellular neighborhoods. Despite the positive impact of CAF proportions on survival, patients with enrichment of platelet-derived growth factor receptor beta (PDGFRB)-positive CAFs in the vicinity of HRS cells had worse survival in both cohorts, independent of the clinical determinants. Our findings distinguish various subsets of CAFs and macrophages impacting survival in cHL and underscore the importance of the spatial arrangements in the TME.

Single-Cell Transcriptomic Analysis Reveals an Aggressive Basal-Like Tumor Cell Subpopulation Associated With Poor Prognosis in Intrahepatic Cholangiocarcinoma

BACKGROUND AND AIM

Intrahepatic cholangiocarcinoma (ICC) is the second most common primary liver cancer whose incidence is increasing globally. However, the high tumor heterogeneity of ICC restricts the efficacy of available systematic therapies. We aim to dissect the tumor heterogeneity of ICC utilizing high-resolution single-cell RNA sequencing to identify novel therapeutic targets.

METHODS

We performed single-cell RNA sequencing (scRNA-seq) of 26 tumor samples from 23 ICC patients and spatial transcriptomic sequencing of six tumor sections from six ICC patients. Bulk RNA-seq data from two public datasets were used for validation. Additionally, immunohistochemical staining and multiplex immunofluorescence staining were conducted to validate the infiltration and distribution of cells in the tumor microenvironment.

RESULTS

We discovered that malignant cells in ICC samples exhibited a remarkably high degree of tumor heterogeneity. We identified a basal-like tumor cell subpopulation characterized by the expression of basal epithelial related genes including KRT5, KRT6A, and KRT17. The basal-like tumor subpopulation was characterized by activation of MET signaling and extracellular matrix organization associated with tumor invasion and correlated with poor prognosis. Cell-cell communication analysis further showed significant HGF-MET interaction between inflammatory cancer-associated fibroblasts (iCAFs) and basal-like tumor cells. We found that iCAFs were the major source of HGF in tumor environment and contributed to the basal-like phenotype formation of tumor cells by HGF-MET axis.

CONCLUSIONS

We identified an aggressive basal-like tumor cell subpopulation, which correlated with poor prognosis in ICC. The MET pathway contributes to the aggressiveness of basal-like tumor cells and serves as a novel therapeutic target for ICC.

Mechanistic role of stromal cancer-associated fibroblasts in tumorigenesis and brain metastasis: Highlighting drug resistance and targeted therapy

Brain metastases remain a major clinical challenge due to their high resistance to conventional and targeted therapies. Cancer-associated fibroblasts are the most common cellular component of the brain metastases tumor microenvironment. They significantly impact the tumor microenvironment because they promote cancer cell invasion, enhance metastasis, boost immune evasion, and contribute to drug resistance. We searched the PubMed and Google Scholar databases and included 99 studies to summarize the present review. Based on the searched articles, the present review emphasizes that biomarkers including PDGFR-β, α-SMA, and collagen I can identify metastatic brain cancer-associated fibroblasts, which lead to a poor prognosis and recurrence. In addition, cancer-associated fibroblasts can cause resistance to therapy by modifying the extracellular matrix (e.g., collagen I, fibronectin), secreting growth factors (e.g., TGF-β, HGF, IL-6), causing immunological evasion (e.g., Tregs, MDSCs), secreting exosomes (e.g., miRNAs), metabolic reprogramming, stemness induction, and plasticity. We also describe the molecular mechanisms by which cancer-associated fibroblasts confer drug resistance in brain metastases, such as extracellular matrix restoration, immunological evasion, metabolic reprogramming, etc. We also cover prospective therapeutic options for overcoming medication resistance, such as cancer-associated fibroblasts depletion, paracrine signaling blockage, metabolic inhibitors, and cancer-associated fibroblasts-targeted immunotherapies. Targeting cancer-associated fibroblasts in addition to existing medications may improve cancer treatment efficacy and survival rates for individuals with brain metastases. However, more research is required to better understand their role in metastatic brain tumors.

Tissue mechanics in tumor heterogeneity and aggression

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.

Comprehensive Metabolite Profiling in Single-Cell Systems via Dual-Modal MALDI-Mass Spectrometry Imaging

The development of spatial multiomics technologies, particularly matrix-assisted laser desorption/ionization mass spectrometry imaging (MALDI-MSI), has revolutionized our ability to map metabolic processes at single-cell resolution. However, the current techniques face challenges in minimizing matrix interferences and achieving comprehensive metabolite detection across multiple ionization modes. In this study, we present a novel dual-modal MSI workflow that leverages the pairing of 1,5-diaminonaphthalene (DAN) and its hydrochloric salt (DAN-HCl) matrices for sequential detection in positive- and negative-ion modes, respectively. This approach significantly enhanced metabolite coverage, spanning both lipid-based and nonlipid small molecules, while eliminating the need for solvent cleaning steps. Applied to a coculture of cholangiocarcinoma (CCLP1) and hepatic stellate (LX2) cells, the workflow revealed significant metabolic distinctions, including differential accumulation of glycerolipids and energy-related metabolites, highlighting the unique metabolic profiles of each cell type. Additionally, several unidentified metabolites were detected, indicating the potential to discover novel metabolic variations. These findings establish our method as a robust tool for single-cell spatial metabolomics with broad applicability in studying complex cellular interactions and advancing both research and clinical applications.

The INAVA mRNA in Extracellular Vesicles Activates Normal Ovarian Fibroblasts by Phosphorylation-Ubiquitylation Crosstalk of HMGA2

Ovarian cancer is an aggressive gynecological tumor usually diagnosed with widespread metastases. Extracellular vesicles (EVs), though recognized as important mediators of tumor metastasis, have received limited attention into their specific functions via the mRNA profiling. Here it is reported elevated expression and selective enrichment of INAVA mRNA in both plasma- and tissue-derived EVs from ovarian cancer patients, which is positively correlated with distant metastasis and poor prognosis. Functionally, INAVA mRNA, upon uptake and translation, activates normal ovarian fibroblasts (NOFs) and drives extensive peritoneum metastasis in the orthotopic xenograft mouse model. Mechanistically, INAVA competitively binds with high mobility group protein A2 (HMGA2) and consequently inhibit its interaction with vaccinia-related kinase 1 (VRK1), leading to reduced HMGA2 phosphorylation on Ser105. Interestingly, this inhibitory phosphorylation stabilizes HMGA2 via blocking tripartite motif-containing 21 (TRIM21) -mediated K48-linked ubiquitylation, and ultimately enhances the transcription of STAT3 to activate NOFs. Lastly, a cell-permeable peptide that disrupts the INAVA-HMGA2 interaction leads to attenuated NOF activation and provides a promising strategy for ovarian cancer therapy.

THBS2-producing matrix CAFs promote colorectal cancer progression and link to poor prognosis via the CD47-MAPK axis

Cancer-associated fibroblasts (CAFs) display significant functional and molecular heterogeneity within the tumor microenvironment, playing diverse roles in cancer progression. Employing single-cell RNA sequencing data of colorectal cancer (CRC), we identified a subset of matrix CAFs (mCAFs) as a critical subtype that secretes THBS2, a molecule linked to advanced cancer stages and poor prognosis. Spatial transcriptomics and multiplex immunohistochemistry revealed clear spatial colocalization between THBS2-producing mCAFs and tumor cells. Mechanically, CAF-secreted THBS2 binds to CD47 on tumor cells, triggering the MAPK/ERK5 signaling pathway, which enhances tumor progression. The tumor-promoting role of THBS2 was further validated using fibroblast-specific THBS2 knockout mice, patient-derived organoids, and xenografts. Moreover, the transcription factor CREB3L1 was identified as a regulator of the transformation of normal fibroblasts into THBS2-producing mCAFs. These findings underscore the pivotal role of THBS2 in CRC progression and highlight the therapeutic potential of targeting the THBS2-CD47 axis and CREB3L1 in CRC.

hnRNPA2B1 facilitates ovarian carcinoma metastasis by sorting cargoes into small extracellular vesicles driving myofibroblasts activation

BACKGROUND

Ovarian carcinoma (OvCa) metastasis is initiated and boosted by tumor-stroma interactions mediated by small extracellular vesicles (sEVs) containing microRNAs (miRNAs). However, the mechanisms of sorting relevant miRNAs into tumoral sEVs remain elusive.

RESULTS

In this study, among the RNA-binding proteins, hnRNPA2B1 was identified as the most significant factor associated with survival in OvCa patients, and its expression was higher in omental metastases compared to paired ovarian lesions. Based on the CRISPR-Cas9 technique, orthotopic xenograft mice revealed a remarkable metastasis-inhibiting effect of hnRNPA2B1-knockdown, accompanied by diminished myofibroblast signals in the omentum. Meanwhile, after hnRNPA2B1-knockdown, OvCa-sEVs largely lost the ability to promote omental metastasis and myofibroblast activation in vivo and in vitro. High-throughput miRNA sequencing of sEV cargoes revealed that UAG motif-containing miRNAs were significantly affected by hnRNPA2B1, and RNA immunoprecipitation (RIP) verified their direct binding to hnRNPA2B1. In pull down assays, the miRNAs with mutated UAG motif exhibited decreased binding capacity to hnRNPA2B1. The myofibroblasts activated by OvCa-sEVs could promote tumor metastasis, and this effect was notably impacted by manipulating hnRNPA2B1, related sEV-miRNAs, and PI3K/AKT signaling.

CONCLUSIONS

These findings highlight the miRNA sorting to sEVs mediated by hnRNPA2B1 as an important mechanism involved in OvCa metastasis, which may illuminate new therapeutic strategies.

The FBXW7-KMT2 axis in cancer-associated fibroblasts controls tumor growth via an epigenetic-paracrine mechanism

F-box and WD repeat domain-containing 7 (FBXW7) is a tumor suppressor that targets various oncoproteins for degradation, but its role in modulating cancer-associated fibroblasts (CAFs) in the tumor microenvironment remains elusive. Here, we report that FBXW7 expression is gradually downregulated in CAFs during the progression of human pancreatic and lung cancers. Mechanically, FBXW7 inhibits histone lysine methyltransferase 2 (KMT2) methyltransferase activity via retinoblastoma binding protein 5 (RbBP5) binding, whereas FBXW7 depletion abrogates the binding to activate KMT2, leading to increased H3K4 methylations and global upregulation of gene expression. Activation of the interleukin-17 (IL-17) signaling pathway triggers the secretion of cytokines and chemokines to promote migration, invasion, and sphere formation of lung cancer cells. Coinjection of Fbxw7-depleted mouse embryonic fibroblasts with cancer cells enhances in vivo tumor growth, demonstrating a paracrine effect. Hypoxia downregulates CAF FBXW7 via ETS proto-oncogene 1 (ETS1) to increase H3K4 methylation, whereas conditioned media from hypoxia-exposed CAFs promotes migration and invasion of pancreatic cancer cells, highlighting FBXW7's tumor-suppressing role through KMT2 inactivation.

Cancer-associated fibroblasts in breast cancer in the single-cell era: Opportunities and challenges

Breast cancer is a leading cause of morbidity and mortality in women, and its progression is closely linked to the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs), key components of the TME, play a crucial role in promoting tumor growth by driving cancer cell proliferation, invasion, extracellular matrix (ECM) remodeling, inflammation, chemoresistance, and immunosuppression. CAFs exhibit considerable heterogeneity and are classified into subgroups based on different combinations of biomarkers. Single-cell RNA sequencing (scRNA-seq) enables high-throughput and high-resolution analysis of individual cells. Relying on this technology, it is possible to cluster complex CAFs according to different biomarkers to analyze the specific phenotypes and functions of different subpopulations. This review explores CAF clusters in breast cancer and their associated biomarkers, highlighting their roles in disease progression and potential for targeted therapies.

Tumor-stroma proportion is associated with increased M2 macrophage abundance and predicts the resistance to immune checkpoint blockade in breast cancer

BACKGROUND

The tumor stroma has been reported to be associated with worse prognosis in several solid tumors, but its prognostic value in breast cancer (BRCA) is still undefined.

METHODS

In this research, multiple public and in-house patient cohorts were collected to demonstrate the clinical and immune correlations of tumor-stroma proportion (TSP) in BRCA. In addition, in vitro assays uncovered the oncogenic role of TSP-related collagen in BRCA.

RESULTS

High TSP status based on hematoxylin and eosin (HE) staining was associated with positive hormone receptor status, advanced clinical stages, and poor immune checkpoint blockade (ICB) response. In addition, we developed a RNA-sequencing (RNA-seq)-based stromal score based on four critical genes expression (AEBP1, COL6A3, CTSK, and PLAC9). Both TSP status and stromal score were positively associated with increased M2 macrophage abundance in BRCA. Moreover, tumor collagen has been found to be enriched in samples with the high TSP status, and collagen promoted BRCA cells aggressiveness and macrophage M2 polarization.

CONCLUSIONS

The tumor stroma was found to be notably related to poor ICB response in patients with BRCA as a result of tumor stroma-macrophage interactions. Thus, the TSP status could predict the clinical outcomes of BRCA patients receiving ICB therapy.

Unveiling FKBP7 as an early endoplasmic reticulum sentinel in pancreatic stellate cell activation, collagen remodeling and tumor progression

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.

Repeated sequential administration of pegylated emulsion of SU5416 and liposomal paclitaxel enhances anti-tumor effect in 4T1 breast cancer-bearing mice

To improve vascular normalization strategy for intractable triple-negative breast cancer 4T1, we examined the anti-tumor effects of repeated sequential administration of polyethylene glycol (PEG)-modified emulsion of SU5416 (PE-SU5416), a vascular endothelial growth factor (VEGF) receptor-2 kinase inhibitor, and PEG-modified liposomal paclitaxel (PL-PTX) in mice bearing 4T1 cells. Three sequential administrations (Seq×3) of PE-SU5416 and PL-PTX exhibited significantly higher anti-tumor activity than a single sequential administration (Seq×1). The tumor vasculatures were structurally normalized until after two PE-SU5416 (PE-SU5416×2) or sequential (Seq×2) administrations, while the improvement in vascular function, such as oxygen supply, blood flow, and PEG-liposomal distribution, was evident until after three administrations of PE-SU5416 (PE-SU5416×3) and Seq×3. Although some discrepancies between the structural and functional improvement in tumor vasculatures were observed after PE-SU5416×3 and Seq×3, cancer-associated fibroblasts (CAFs) and collagen levels were significantly reduced after PE-SU5416×2, PE-SU5416×3, Seq×2, and Seq×3, suggesting that a possible decrease in interstitial fluid pressure due to the reduction in CAFs and collagen would have compensated for vascular function. Furthermore, PE-SU5416×2, PE-SU5416×3, Seq×2, and Seq×3 significantly decreased tumor growth factor-β (TGF-β), an activator of CAFs, in tumor tissues, suggesting that the reduction in TGF-β levels by PE-SU5416 suppresses CAF activation.

High antigen-presenting CAF levels correlate with reduced glycosaminoglycan biosynthesis-heparan sulfate/heparin metabolism in immune cells and poor prognosis in esophageal squamous cell carcinoma: Insights from bulk and single-cell transcriptome profiling

In esophageal squamous cell carcinoma (ESCC), the tumor microenvironment (TME) is characterized by a significant accumulation of cancer-associated fibroblasts (CAFs), which play a pivotal role in the host response against tumor cells. While fibroblasts are known to be crucial in the metabolic reprogramming of the TME, the specific metabolic alterations induced by these cells remain largely undefined. Utilizing single-cell RNA sequencing, we have identified a distinct subpopulation of antigen-presenting CAF (apCAF) within ESCC tumors. Our findings reveal that apCAF contribute to adverse patient outcomes by remodeling the tumor metabolic environment. Notably, apCAF modulate the glycosaminoglycan biosynthesis-heparan sulfate/heparin metabolism pathway in T cells, B cells, and macrophages. Disruption of this pathway may facilitate immune evasion by the tumor. These insights underscore the critical role of CAFs in shaping the metabolic landscape of the TME and lay the groundwork for developing therapeutic strategies aimed at enhancing anti-tumor immunity.

Spatial relationships and interactions of immune cell niches are linked to the pathologic response of muscle-invasive bladder cancer to neoadjuvant therapy

BACKGROUND

The identification of the complex spatial architecture of immune cell infiltration and its interaction mechanisms within tumor ecosystems provides crucial insights into therapeutic responses to neoadjuvant therapy in muscle-invasive bladder cancer (MIBC). This study aims to characterize the spatial features of distinct cell-type niches within the tumor microenvironment (TME) of patients with varying responses to neoadjuvant therapy.

METHODS

We performed spatial transcriptomic profiling on six MIBC specimens obtained from a registered clinical trial (ChiCTR2000032359), generating whole-transcriptome spatial atlases to map the TME architecture. High-throughput analytical frameworks were employed to deconstruct the TME, and key findings were validated through immunohistochemistry and mouse model experiments.

RESULTS

Our analysis revealed that tissues from complete responders exhibited greater infiltration of T and B cells, with the formation of tertiary lymphoid structure (TLS). Trajectory analysis identified CCL19/CCL21 as the key signaling molecules driving TLS formation in MIBC. Mouse experiments demonstrated that recombinant CCL19/CCL21 protein injections promoted intratumoral TLS formation and enhance the efficacy of immunotherapy. Furthermore, we observed significant intrinsic heterogeneity within individual tumors, which may contribute to the lack of therapeutic efficacy in MIBC.

CONCLUSIONS

This study underscores the critical role of TLS formation in the response to neoadjuvant therapy in MIBC. We identified CCL19/CCL21 as key drivers of TLS formation within MIBC tumors and potential immune-sensitizing agents. Additionally, the intrinsic heterogeneity of tumor should be considered a significant factor influencing therapeutic efficacy.

Endothelial-like cancer-associated fibroblasts facilitate pancreatic cancer metastasis via vasculogenic mimicry and paracrine signalling

BACKGROUND

Cancer-associated fibroblasts (CAFs) are highly heterogeneous in the progression of pancreatic ductal adenocarcinoma (PDAC) and vasculogenic mimicry (VM) refers to a phenomenon in which cancer cells adopt endothelial-like characteristics.

OBJECTIVE

To identify a novel protumoural CAF subtype undertaking VM.

DESIGN

We used single-cell RNA sequencing and mIHC to identify FAPα+CD144+ endothelial-like CAFs (endoCAFs) and combined prospective and retrospective analyses to assess its clinical outcomes. Tube formation, proliferation and invasion assay were conducted on cell lines, organoids, the orthotopic tumour model and LSL-KrasG12D/+, LSL-Trp53R172H/+ and Pdx1-Cre (KPC) mouse model. Mechanically, we performed cytokine array assays, RNA-sequencing, IP-mass spectrometry, ChIP and luciferase analyses. Importantly, an siRNA delivery nanosystem was developed to precisely target FAPα+CD144+endoCAFs in vivo.

RESULTS

FAPα+CD144+endoCAFs were present in the tumour microenvironment of PDAC, and patients with a higher CD144+CAFs proportion displayed poor prognosis of PDAC. FAPα+CD144+endoCAFs not only acquired a VM phenotype to provide metastatic conduits but also promoted the proliferation and invasion of tumour cells in situ through paracrine signalling, thereby actively facilitating the metastasis of tumour cells. The CD144-β-catenin-STAT3 signalling axis was activated, and CD144 and downstream secreted cytokines were transcriptionally upregulated to maintain the dual roles of endoCAFs. A CAF-targeting siRNA delivery nanosystem, via loading FAPα and siCD144, was administered to precisely target FAPα+CD144+ endoCAFs, which substantially inhibited their protumoural roles in vivo.

CONCLUSION

FAPα+CD144+endoCAFs can promote metastasis of PDAC via undertaking VM and paracrine through activation of the CD144-β-catenin-STAT3 signalling axis. CAF-targeting siRNA delivery nanosystem can inhibit tumour progression by precisely targeting FAPα+CD144+endoCAFs.

Immune-featured stromal niches associate with response to neoadjuvant immunotherapy in oral squamous cell carcinoma

Tumor stromal cells (TSCs) play a crucial yet underexplored role in the tumor microenvironment (TME). This study uses single-cell sequencing and spatial transcriptomics on paired tumor specimens from 22 patients with oral squamous cell carcinoma (OSCC) enrolled in a randomized two-arm phase 2 trial, receiving neoadjuvant anti-PD-1 mono-immunotherapy or anti-PD-1 plus docetaxel-cisplatin-5-fluorouracil (TPF) immunochemotherapy. Single-cell analysis reveals increased TSCs within the TME of responders in immunochemotherapy. Notably, significant post-treatment upregulation of SELP+ high endothelial venules (HEVs) and APOD+ myofibroblastic cancer-associated fibroblasts (myCAFs), alongside a decline in STMN1+ capillary endothelial cells (cECs), is specific to the immunochemotherapy cohort. In contrast, MYF5+ muscle satellite cells (MSCs) are upregulated in non-responders to mono-immunotherapy. SELP+ HEVs and APOD+ myCAFs foster favorable immunomodulatory stromal niches for improved outcomes, while STMN1+ cECs and MYF5+ MSCs form immunosuppressive niches in tumor invasion regions, highlighting therapeutic targets. The trial was registered at ClinicalTrials.gov, and the registration number is NCT04649476.

Tumor cell-derived ISG15 promotes fibroblast recruitment in oral squamous cell carcinoma via CD11a-dependent glycolytic reprogramming

Cancer-associated fibroblast (CAF) recruitment and activation within the tumor microenvironment (TME) are increasingly acknowledged as drivers of oral squamous cell carcinoma (OSCC) tumor growth and metastasis. Therefore, the mechanisms underlying tumor cell and fibroblast crosstalk warrant further investigation. We discovered that ectopic interferon-stimulated gene 15 (ISG15) expression, which is a promising and novel oncoprotein biomarker elevated in a variety of cancers, enhanced OSCC growth and elevated collagen and α-smooth muscle actin (α-SMA) expression in ISG15-expressing tumors. Analysis of immunohistochemistry revealed high ISG15 expression in human oral tissues correlated with high expression of α-SMA and fibroblast activation protein (FAP). Fibroblast migration and recruitment by ISG15-expressing OSCC cells were confirmed by in vitro and in vivo experiments. Exogenous ISG15 induced fibroblast migration, morphological changes, and vimentin expression. Enrichment of glycolysis pathway genes, as well as increased glycolysis-related gene expression, glucose uptake, and lactate production were observed in ISG15-treated fibroblasts. Lactate release and fibroblast migration were blocked by a competitive inhibitor of glucose metabolism. Furthermore, the knockdown of integrin αL (ITGAL)/CD11a, a subunit of ISG15 receptor lymphocyte functional-associated antigen-1 (LFA-1), in immortalized fibroblasts diminished extracellular ISG15-mediated glycolysis and migration. Our findings suggest that ISG15 derived from OSCC cells interacts with fibroblasts through the LFA-1 receptor, leading to glycolytic reprogramming and promotion of fibroblast migration into the TME.

Single-cell multi-stage spatial evolutional map of esophageal carcinogenesis

Cancer development involves the co-evolution of cancer cells and their surrounding microenvironment, yet the dynamics of this interaction within the physical architecture remains poorly understood. Here, we present a spatial transcriptomic map at single-cell resolution, encompassing 127 multi-stage fields of view from 43 patients, to chart the evolutionary trajectories of human esophageal squamous cell carcinoma (ESCC). By analyzing 6.4 million cells, we reveal that ESCC progression is driven by a proliferative epithelial cell subpopulation that acquires dedifferentiated and invasive characteristics. At the late precancerous stage, these cells disrupt the epithelial-stromal interface and recruit normal fibroblasts via JAG1-NOTCH1 signaling, transforming them into cancer-associated fibroblasts (CAFs). This interaction leads to the formation of a "CAF-Epi" (CAF and epithelial cell) niche at the tumor edge that shields the tumor from immune surveillance. The CAF-Epi niche formation is a key indicator of progression in ESCC and other squamous cell carcinomas and patient outcomes.

Single-cell and spatial transcriptome profiling reveal CTHRC1+ fibroblasts promote EMT through WNT5A signaling in colorectal cancer

BACKGROUND

Cancer-associated fibroblasts (CAFs), known for facilitating the progression and metastasis of colorectal cancer (CRC), have become a promising therapeutic target. However, the significant heterogeneity of CAFs and their intricate crosstalk with tumor cells present substantial challenges in the development of precise and effective therapeutic strategies.

METHODS

Single-cell RNA sequencing (scRNA-seq) technology was used to identify various cell subtypes. Spatial transcriptomics (ST) was employed to map the spatial niches and colocalization patterns of these cell subtypes. Cell-cell interactions among these subtypes were analysed via CellChat and NicheNet software. Tumor cell invasion, migration, and proliferation were assessed through wound healing assays, transwell assays, colony formation assays, and xenograft mouse models.

RESULTS

We identified a significant spatial colocalization between CTHRC1+ CAFs and a distinct subtype of malignant epithelial cells, both residing within the EMT-active spatial niche. Our results demonstrate that CTHRC1+ CAFs, as a major source of WNT5A, promote epithelial-mesenchymal transition (EMT) and enhance tumor cell invasiveness by upregulating MSLN expression in adjacent malignant epithelial cells. This signaling axis contributes significantly to CRC progression and metastasis.

CONCLUSIONS

Targeting the CTHRC1+ CAF-WNT5A-MSLN signaling axis presents a promising therapeutic strategy for advanced CRC patients. Our study provides new insights into the role of CAFs in CRC progression and offers potential avenues for developing targeted therapies to disrupt this pathway.

Pancreatic cancer-derived extracellular vesicles enhance chemoresistance by delivering KRASG12D protein to cancer-associated fibroblasts

KRAS mutations are instrumental in the development and progression of pancreatic ductal adenocarcinoma (PDAC). Nevertheless, the efficacy of direct targeting of KRAS mutations to inhibit tumor development remains doubtful. It is therefore necessary to gain a deeper insight into the mechanism in which KRAS mutations influence the effectiveness of clinical treatments. In this study, KRASG12D protein was detected in cancer-associated fibroblasts (CAFs) from clinical samples of PDAC. In vitro experiments demonstrated that KRASG12D protein in CAFs was not expressed from its own mutant gene but was derived from the ingestion of tumor cell-derived extracellular vesicles (EVs). The presence of KRASG12D protein in CAFs resulted in enhanced proliferation and migration. Furthermore, KRASG12D-containing CAFs were observed to promote tumor chemoresistance to gemcitabine treatment both in vitro and in vivo. Application of a KRAS mutation-specific inhibitor, MRTX1133, has been demonstrated to reverse chemoresistance in PDAC. Moreover, clinical data suggest that patients with KRAS mutations have poorer prognosis following adjuvant chemotherapy. These findings elucidate the mechanism by which oncogenic KRAS mutations promote cancer chemoresistance and remodel tumor environment in a non-autonomous manner, suggesting a novel strategy for targeting KRAS mutations to enhance chemosensitivity in PDAC.

Multi-omics analysis of the dynamic role of STAR+ cells in regulating platinum-based chemotherapy responses and tumor microenvironment in serous ovarian carcinoma

Background

Serous ovarian carcinoma (SOC) is the most lethal subtype of ovarian cancer, with chemoresistance to platinum-based chemotherapy remaining a major challenge in improving clinical outcomes. The role of the tumor microenvironment (TME), particularly cancer-associated fibroblasts (CAFs), in modulating chemotherapy responses is not yet fully understood.

Methods

To explore the relationship between CAF subtypes and chemotherapy sensitivity, we employed single-cell RNA sequencing (scRNA-seq), bulk RNA-seq, spatial transcriptomics, immunohistochemistry (IHC), and immunofluorescence (IF). This multi-omics approach enabled the identification, characterization, and functional analysis of CAF subtypes in both chemotherapy-sensitive and chemotherapy-resistant SOC patients.

Results

We identified steroidogenic acute regulatory protein-positive (STAR+) cells as a novel CAF subtype enriched in chemotherapy-sensitive SOC patients. STAR + cells exhibited unique transcriptional profiles and were functionally enriched in pathways related to P450 drug metabolism, lipid metabolism, and amino acid metabolism, with enhanced pathway activity observed in chemotherapy-sensitive groups. Spatial transcriptomics and IF revealed that STAR + cells were closely localized to tumor cells, suggesting potential cell-cell interactions. Further communication analysis indicated that STAR + cells may suppress WNT signaling in tumor cells, contributing to improved chemotherapy responses. Importantly, STAR expression levels, validated by IHC, were positively correlated with chemotherapy sensitivity and improved patient prognosis. Platinum-based chemotherapy was shown to increase the proportion of STAR + cells, underscoring their dynamic response to treatment.

Conclusion

Our study identifies STAR + cells as a novel CAF subtype that enhances chemotherapy sensitivity in SOC. By modulating key metabolic pathways and potentially suppressing WNT signaling, STAR + cells could contribute to improved treatment responses. These findings position STAR + cells as a promising biomarker for predicting chemotherapy efficacy in SOC, which warrants further investigation.

Evaluation of a Novel Gd-FAPI Dimer Molecular Probe Targeting Fibroblast Activation Protein for Imaging of Solid Tumors

Cancer-associated fibroblasts (CAFs) are essential components of the tumor microenvironment. Fibroblast activation protein (FAP) is overexpressed in CAFs. FAP-targeted molecular imaging agents, including the FAP inhibitors (FAPIs), have shown promising results in tumor diagnosis. We aimed to design a Gd-labeled FAPI Dimer, Gd-DOTA-Suc-Lys-(FAPI04)2, to optimize the pharmacokinetics and evaluate its potential capacity for targeting FAP-positive solid tumors in vivo. The Gd-labeled FAPI Dimer was successfully synthesized with exceeding 98% purity. Preclinical pharmacokinetics were determined in assessed FAP-positive U87 cell-derived xenografts and FAP-negative C6-derived xenografts using small-animal T1-weighted 7.0T MR imaging. The longitudinal correlation coefficient (r1) of the agent was 3.813 mM-1·S-1. The administration of the Gd-FAPI04 Dimer probe showed a notable enhancement of tumor contrast on T1-weighted whole-body MRI. At 10 and 30 minutes post-injection, the U87 subcutaneous tumor demonstrated significantly greater contrast enhancement than the C6 subcutaneous tumor (P <0.05). In vivo, the safety of the Gd-FAPI-04 Dimer probe was evaluated, which showed no tissue damage in vital organs like the heart, liver, spleen, lung, and kidneys, as indicated by unchanged morphology compared to a normal saline control group. The novel Gd-FAPI04 Dimer molecular probe, Gd-DOTA-Suc-Lys-(FAPI-04)2 specifically targeting FAP may serve as a safe and promising tool for the diagnostic imaging of solid tumors.

Extracellular matrix cancer-associated fibroblasts promote stromal fibrosis and immune exclusion in triple-negative breast cancer

The impact of high heterogeneity of cancer-associated fibroblasts (CAFs) on triple-negative breast cancer (TNBC) immunotherapy response has not been fully elucidated, restricting progress in precision immuno-oncology. We integrated single-cell transcriptomic data from 18 TNBC patients and analyzed fibroblast subpopulations. Extracellular matrix CAFs (ecmCAFs) were identified as a fibroblast subpopulation with distinct ECM-associated characteristics. The ecmCAFs were significantly enriched in TNBC patients with residual disease after neoadjuvant immunotherapy and contributed to a fibrotic tumor microenvironment and T-cell exclusion. Secreted phosphoprotein 1 (SPP1) positive macrophages (SPP1+ Mφs) were closely localized to ecmCAFs and produced more transforming growth factor beta (TGFB1), interleukin 1 beta (IL1B), and SPP1 under hypoxic conditions. SPP1+ Mφs were found to facilitate the differentiation of normal breast fibroblasts to ecmCAFs, thus promoting ECM remodeling and stromal fibrosis. Our work revealed the critical role of ecmCAFs in generating a desmoplastic architecture and driving immunosuppression in TNBC. © 2025 The Pathological Society of Great Britain and Ireland.

Bioprinted Fibroblast Mediated Heterogeneous Tumor Microenvironment for Studying Tumor-Stroma Interaction and Drug Screening

Cancer-associated fibroblasts (CAFs) are crucial stromal cells in the tumor microenvironment, affecting cancer growth, angiogenesis, and matrix remodeling. Developing an effective in vitro tumor model that accurately recapitulates the dynamic interplay between tumor and stromal cells remains a challenge. In this study, a 3D bioprinted fibroblast - mediated heterogeneous breast tumor model was created, with tumor cells and fibroblasts in a bionic matrix. The impact of transforming growth factor-β （TGF-β） on the dynamic transformation of normal fibroblasts into CAFs and its subsequent influence on tumor cells is further investigated. These findings reveales a profound correlation between CAFs and several critical biological processes, including epithelial-mesenchymal transition (EMT), extracellular matrix (ECM) remodeling, gene expression profiles, and tumor progression. Furthermore, tumor models incorporating CAFs exhibits reduced drug sensitivity compared to models containing tumor cells alone or models co-cultured with normal fibroblasts. These results underscore the potential of the in vitro fibroblast-mediated heterogeneous tumor model to simulate real-life physiological conditions, thereby offering a more effective drug screening platform for elucidating tumor pathogenesis and facilitating drug design prior to animal and clinical trials. This model's establishment promotes the understanding of tumor-stromal interactions and their therapeutic implications.

The extracellular matrix protein type I collagen and fibronectin are regulated by β-arrestin-1/endothelin axis in human ovarian fibroblasts

BACKGROUND

The invasive and metastatic spread of serous ovarian cancer (SOC) results from the cooperative interactions between cancer and stroma, which include extracellular matrix (ECM) and cellular components, including cancer-associated fibroblasts (CAFs). Soluble factors secreted by cancer and stromal cells contribute to stroma remodeling through the secretion of ECM proteins, providing a favorable environment for cancer cell dissemination. The peptide endothelin-1 (ET-1), through two G protein-coupled receptors (GPCR), endothelin receptor type A (ETAR) and B (ETBR), acts on both cancer and stromal cells, engaging the protein β-arrestin1 (β-arr1), to bolster SOC progression. However, its role in the regulation of the ECM proteins by ovarian fibroblasts is not understood. This study delves into the role of ET-1 as a regulator of type I collagen (Col1) and fibronectin (FN).

METHODS

We used human primary ovarian fibroblasts (HOFs) and CAFs. The expression of Col1 (COL1A1) and FN (FN1) were detected by western blotting (WB), quantitative real time-polymerase chain reaction (qRT-PCR), immunofluorescence (IF), and confocal laser scanning microscopy (CLSM) in cells and tumor tissue sections from mice xenografts, while the transcription of COL1A1 was detected by luciferase reporter gene assay. The nuclear function of β-arr1 was evaluated by silencing and rescue expression with wild-type (WT) and nuclear mutant plasmid constructs, RNA seq and differential gene expression and gene sets enrichment analyses. The prognostic role of COL1A1, FN1, EDN1 (ET-1) and ARRB1 (β-arr1) gene expression was evaluated using the Kaplan-Meier plotter database and clinical ovarian cancer tissue samples.

RESULTS

We demonstrated that ET-1 boosts Col1 and FN expression in HOFs, akin to ovarian CAF levels. Both receptors are implicated, evident from inhibitory effects after ETAR or ETBR antagonist treatments and notably with bosentan, a dual antagonist, in vitro and in vivo. At the molecular level, ET-1 triggers the activation of COL1A1 promoter activity and its enhanced expression via β-arr1 nuclear function. Transcriptome analysis of β-arr1-silenced HOFs confirms the nuclear role of β-arr1 in collagen and ECM remodeling-related protein transcriptional regulation. Accordingly, a high level of EDN1/ARRB1 expression in combination with either COL1A1 or FN1 is associated with the poor prognosis of SOC patients.

CONCLUSIONS

These findings hint at ET-1 involvement in ECM remodeling and early SOC stages by modulating the expression of Col1 and FN. Targeting ET-1 signaling with ETAR/ETBR antagonists might interfere with the ability of CAFs to produce key ECM proteins in this tumor.

A novel HVEM-Fc recombinant protein for lung cancer immunotherapy

BACKGROUND

The ubiquitously expressed transmembrane protein, Herpesvirus Entry Mediator (HVEM), functions as a molecular switch, capable of both activating and inhibiting the immune response depending on its interacting ligands. HVEM-Fc is a novel recombinant fusion protein with the potential to eradicate tumor cells.

METHODS

The anti-tumor efficacy of HVEM-Fc was evaluated in C57BL/6 mice-bearing lung cancer models: a syngeneic model and an orthotopic model of mouse lung cancer. Additionally, patient-derived organoids were employed in conjunction with T cell co-culture systems. To investigate the underlying mechanisms, a comprehensive array of techniques was utilized, including single-cell RNA sequencing, spatial transcriptomics, bulk RNA sequencing, and flow cytometry. Furthermore, the anti-tumor effects of HVEM-Fc in combination with Programmed Death-1 (PD-1) inhibitors were assessed. Finally, mouse immune cell depletion antibodies were used to elucidate the underlying mechanisms of action.

RESULTS

In vivo, 1 mg/kg HVEM-Fc demonstrated effective inhibition of tumor growth and metastasis in C57BL/6 mice bearing lung cancer model and a KP orthotopic model of mouse lung cancer. Multi-omics analysis showed that HVEM-Fc induced an immune-stimulatory microenvironment. Notably, the combination of HVEM-Fc with a PD-1 inhibitor demonstrated the most potent inhibition of tumor cell growth. In vitro, HVEM-Fc was validated to eradicate tumor cells through the activation of T cells in both non-small cell lung cancer (NSCLC) organoids and T cell co-culture models.

CONCLUSIONS

Our data demonstrate that HVEM-Fc exerts a strong signal that augments and prolongs T-cell activity in both murine models and human NSCLC organoid models. Moreover, the combination of HVEM-Fc with a PD-1 inhibitor yields the most effective anti-tumor outcomes.

Engineered mesenchymal stem/stromal cells against cancer

Mesenchymal stem/stromal cells (MSCs) have garnered attention for their potential in cancer therapy due to their ability to home to tumor sites. Engineered MSCs have been developed to deliver therapeutic proteins, microRNAs, prodrugs, chemotherapy drugs, and oncolytic viruses directly to the tumor microenvironment, with the goal of enhancing therapeutic efficacy while minimizing off-target effects. Despite promising results in preclinical studies and clinical trials, challenges such as variability in delivery efficiency and safety concerns persist. Ongoing research aims to optimize MSC-based cancer eradication and immunotherapy, enhancing their specificity and efficacy in cancer treatment. This review focuses on advancements in engineering MSCs for tumor-targeted therapy.

Spatially resolved transcriptomics reveal the determinants of primary resistance to immunotherapy in NSCLC with mature tertiary lymphoid structures

Effectiveness of immune checkpoint inhibitors (ICIs) in non-small cell lung cancer (NSCLC) has been linked to the presence of mature tertiary lymphoid structures (mTLSs) within the tumor microenvironment (TME). However, only a subset of mTLS-positive NSCLC derives benefit, thus highlighting the need to unravel ICI response determinants. The comprehensive analysis of ICI-treated patients with NSCLC (n = 509) from the Bergonié Institute Profiling (BIP) study (NCT02534649) reveals that the presence of mTLSs correlates with improved clinical outcomes, independently of programmed death ligand 1 (PD-L1) expression and genomic features. Employing spatial transcriptomics alongside multiplex immunofluorescence (mIF), we show that two distinct subsets of cancer-associated fibroblasts (CAFs) are essential factors in mediating primary resistance to ICIs in mTLS-positive NSCLC. These CAFs are associated with immune exclusion, CD8+ T cell exhaustion, and increased regulatory CD4+ T cell infiltration, underscoring an immunosuppressive TME. Our study highlights the pivotal role of specific CAF subsets in thwarting ICIs, proposing new therapeutic targets to enhance immunotherapy efficacy.

Comprehensive analysis of the multifaceted role of ITGAV in digestive system cancer progression and immune infiltration

Background

Digestive system cancers are among the most common malignancies, exhibiting consistently high incidence and mortality rates, yet effective detection and treatment targets remain limited. Integrin αv (ITGAV, CD51) is a significant member of the integrin family, widely recognized for its role in mediating interactions between cells and the extracellular matrix, as well as intracellular signaling. In recent years, ITGAV has been found to have significantly elevated expression in multiple tumors, such as prostate cancer, breast cancer, and osteosarcoma, and was considered to be a key component in various stages of tumor progression. However, no systematic digestive system cancer analysis has been conducted to explore its function in prognosis, diagnosis, and immunology.

Methods

Transcriptome sequencing and clinical data of samples were obtained from The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression Project (GTEx), Human Protein Atlas (HPA), cBioPortal, TIMER and TISIDB databases. Bioinformatics methods were employed to investigate the potential oncogenicity of ITGAV, focusing specifically on the analysis of its prognosis, diagnostic value, and immune infiltration level of ITGAV in digestive system cancers. In addition, GO, KEGG, and PPI network analysis revealed the biological functions and related signaling pathways related to ITGAV. Finally, the role of ITGAV in regulating cancer progression was experimentally verified using hepatocellular carcinoma and pancreatic cancer as examples.

Results

We found that ITGAV was highly expressed in multiple digestive system cancers. In addition, high expression of ITGAV was closely associated with poor prognosis and showed potential for early diagnosis. Enrichment of pathways related to extracellular matrix organizing processes and tumor migratory movements was identified. In vitro, results showed that the knockdown of ITGAV significantly inhibited the migratory movement ability of hepatocellular carcinoma and pancreatic cancer cells, while its overexpression significantly promoted the migration of the above cells. Finally, immunoassays showed a significant correlation between ITGAV expression and the infiltration level of various immune cells, further clarifying the critical role of ITGAV in the tumor immune microenvironment.

Conclusion

Our results elucidated the importance of ITGAV in the prognostic assessment, early diagnosis, and targeted immunotherapy of digestive system cancers, and revealed its multifaceted role in regulating cancer progression.

Single-cell and spatial-resolved profiling reveals cancer-associated fibroblast heterogeneity in colorectal cancer metabolic subtypes

BACKGROUND

Colorectal cancer (CRC) presents significant treatment challenges due to its high heterogeneity and complex intercellular interactions. Further exploration of CRC subtypes and interactions among tumor-specific clusters will facilitate the development of personalized treatment strategies.

METHODS

Single-cell RNA sequencing and bulk RNA sequencing datasets were integrated to determine CRC metabolic subtypes by hierarchical clustering. The analysis was further extended to cellchat, pseudotime, immune infiltration, and clinicopathological relevance to explore the characteristics of secreted frizzled related protein 2 (SFRP2) + cancer-associated fibroblast (CAF) clusters, and validated by spatial transcriptomics (ST), in vivo experiments, and multiple immunohistochemistry (mIHC).

RESULTS

CRC samples were stably classified into three heterogeneous metabolic subtypes, each exhibiting different microenvironment and CAF heterogeneity, particularly in the distribution of SFRP2 + CAF, which was aligned with metabolic activity. SFRP2 + CAF exhibits high extracellular matrix (ECM) activity and is closely involved in cellular communication, not only promoting the malignant progression of cancer cells but also inducing the differentiation of Tregs. Compared to responders of chemotherapy, the proportion of SFRP2 + CAFs is significantly increased in non-responders. Importantly, mIHC and ST analyses confirm that cancer cells with low expression of agmatinase (AGMAT) can recruit SFRP2 + CAFs, and Treg infiltration surrounding SFRP2 + CAFs was observed. AGMAT combined with oxaliplatin showed the best efficacy in vivo, which may be associated with the inhibition of SFRP2 + CAF infiltration.

CONCLUSIONS

Our study identified and described the potential protumor biological properties of SFRP2 + CAFs, and AGMAT may be a valuable target for disrupting their properties.

FAP-targeting biomimetic nanosystem to restore the activated cancer-associated fibroblasts to quiescent state for breast cancer radiotherapy

Cancer associated fibroblasts (CAFs) are one of the most important stromal cells in the tumor microenvironment, playing a pivotal role in the development, recurrence, metastasis, and immunosuppression of cancer and treatment resistance. Here, we developed a core-shell biomimetic nanosystem termed as FAP-C NPs. This system was comprised of 4T1 extracellular vesicles fused with a FAP single-chain antibody fragment to form the biomimetic shell, and PLGA nanoparticles loaded with calcipotriol as the core. The FAP-modified shell endowed this nanosystem with active targeting ability to CAFs. Calcipotriol, a vitamin D analog, can activate the vitamin D receptor expressed on CAFs, promoting their transition from an activated to quiescent state. This process would help to reduce the pro-tumorigenic signals generated by CAFs, inhibit the stemness of cancer cells, and attenuate the inhibitory effect of CAFs on immune cells. The hydrated particle size of FAP-C NPs was approximately 206 nm, with a narrow distribution (polydispersity index < 0.2). The zeta potential of FAP-C NPs was -12.63 ± 0.61 mV. FAP-C NPs can restore CAFs to a quiescent state to shield the function of activated CAFs, inhibit tumor cell stemness, facilitate the maturation of dendritic cell, and relieve the inhibition of CAFs on lymphocytes. Besides, when combined with radiotherapy, this biomimetic nanosystem could inhibit the activation of CAFs, improve the sensitivity to radiation, and stimulate potent anti-tumor immune response with a 2-fold increase in the infiltration of cytotoxic T cells in tumor microenvironment, thereby effectively suppressing tumor growth with the tumor inhibitory rate as 78.3 %. Therefore, FAP-C NPs hold great potential for targeted breast cancer therapy.

Role of COL5A1 in lung squamous cell Carcinoma: Prognostic Implications and therapeutic potential

BACKGROUND

Lung squamous cell carcinoma (LUSC) is a significant health concern, characterized by a lack of specific therapies and limited treatment options for patients in advanced stages. This study aims to identify key molecules of prognostic importance in LUSC and provide an experimental foundation for their potential therapeutic applications.

METHODS

Immune-related transcriptome expression analysis was performed on LUSC samples using the NanoString digital gene analysis system to develop a prognostic transcriptomic signature. This was followed by validation within the LUSC cohort database, and the immune properties and cellular functions of the critical molecule were examined through molecular biology experiments.

RESULTS

Advanced nCounter analysis revealed significant differences in the numbers of T cells, cytotoxic cells, B cells, and CD45+ and CD8+ T cells between the OS1 (short-term survival) group and the OS2 (long-term survival) group. A comparison of the differences in tumor immune-related pathways between the two groups revealed that signaling pathways such as the PI3K-AKT, NF-kappaB signaling, Notch signaling, angiogenesis, matrix remodeling, and metastasis pathways were activated in the OS1 subgroup, and DNA damage repair and lymphatic chamber signaling pathways were activated in the OS2 subgroup. We analyzed and compared differentially expressed mRNAs with high expression levels in the OS1 and stage IV groups. Collagen type V alpha 1 (COL5A1) was found to be associated with the prognosis of LUSC. Phenotypic analysis revealed that COL5A1 knockdown inhibited the proliferation, migration, and invasion of SKMES1 cells. Locating COL5A1 was shown to be expressed in CAFs, T cells, and EPI cells through single-cell omics analysis.

CONCLUSION

COL5A1 plays a crucial role in tumor progression, indicating that COL5A1 inhibitors may represent a promising therapeutic strategy for the treatment of LUSC.

Cancer-associated fibroblasts promote pro-tumor functions of neutrophils in pancreatic cancer via IL-8: potential suppression by pirfenidone

BACKGROUND

The mechanisms by which neutrophils acquire pro-tumor properties remain poorly understood. In pancreatic cancer, cancer-associated fibroblasts (CAFs) may interact with neutrophils, directing them to promote tumor progression.

METHODS

To validate the association between CAFs and neutrophils, the localization of neutrophils was examined in clinically resected pancreatic cancer specimens. CAFs were produced by culturing in cancer-conditioned media, and the effects of these CAFs on neutrophils were examined. In vitro migration and invasion assays assess the effect of CAF-activated neutrophils on cancer cells. The factors secreted by the activated neutrophils were also explored. Finally, pirfenidone (PFD) was tested to determine whether it could suppress the pro-tumor functions of activated neutrophils.

RESULTS

In pancreatic cancer specimens, neutrophils tended to co-localize with IL-6-positive CAFs. Neutrophils co-cultured with CAFs increased migratory capacity and prolonged life span. CAF-affected neutrophils enhance the migratory and invasive activities of pancreatic cancer cells. IL-8 is the most upregulated cytokine secreted by the neutrophils. PFD suppresses IL-8 secretion from CAF-stimulated neutrophils and mitigates the malignant traits of pancreatic cancer cells.

CONCLUSION

CAFs activate neutrophils and enhance the malignant phenotype of pancreatic cancer. The interactions between cancer cells, CAFs, and neutrophils can be disrupted by PFD, highlighting a potential therapeutic approach.

High prevalence of FAP+ cancer-associated fibroblasts predicts poor outcome in patients with high-grade serous ovarian cancer with high CD8 T-cell density

OBJECTIVE

Studies have implied that fibroblasts may act as regulators of immune cells in the tumor microenvironment (TME). We investigated the clinical relevance of fibroblast activation protein (FAP) positive stroma in high-grade serous ovarian cancer (HGSC) in relation to CD8+ lymphocyte's infiltration.

METHODS

In a discovery cohort (N = 113) of HGSC, expression of FAP and CD8 in the TME was analyzed with immunohistochemistry. Results were correlated with overall survival (OS) and progression-free survival (PFS). The findings were validated in an independent cohort of HGSC (N = 121) and in public available datasets.

RESULTS

High infiltration of CD8+ cells in the TME of HGSC was found to be associated with longer OS, as previously known. Increased expression of FAP was associated with shorter median PFS (11.4 vs. 18.6 months) in tumors with high density of CD8+ cells (HR 4.03, CI 95 % 1.38-11.72, p = 0.01). Similarly, in the validation cohort, high intensity of FAP in cases with high density of CD8+ cells was associated with shorter OS, 31.5 vs 76.9 months (HR 2.83; 95 % CI 1.17-6.86, p = 0.02). The results were consistent in multivariable analyses. The association between high FAP expression and poor outcome in high density CD8 HGSC was also confirmed in publicly available datasets.

CONCLUSIONS

The TME infiltration of FAP-positive fibroblasts is associated with poor prognosis in HGSC with high CD8+ cells density. Targeting the FAP+ subset of fibroblasts may unlock the local immune-activation in the TME thus enhance the positive prognostic effect of T-cells in ovarian cancer.

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.