Interactions between cancer-associated fibroblasts and T-cells: functional crosstalk with targeting and biomarker potential.

Cancer-associated fibroblasts (CAFs) are a heterogeneous cell population recognized as a key component of the tumour microenvironment (TME). Cancer-associated fibroblasts are known to play an important role in maintaining and remodelling the extracellular matrix (ECM) in the tumour stroma, supporting cancer progression and inhibiting the immune system's response against cancer cells. This review aims to summarize the immunomodulatory roles of CAFs, particularly focussing on their T-cell suppressive effects. Cancer-associated fibroblasts have several ways by which they can affect the tumour's immune microenvironment (TIME). For example, their interactions with macrophages and dendritic cells (DCs) create an immunosuppressive milieu that can indirectly affect T-cell anticancer immunity and enable immune evasion. In addition, a number of recent studies have confirmed CAF-mediated direct suppressive effects on T-cell anticancer capacity through ECM remodelling, promoting the expression of immune checkpoints, cytokine secretion and the release of extracellular vesicles. The consequential impact of CAFs on T-cell function is then reflected in affecting T-cell proliferation and apoptosis, migration and infiltration, differentiation and exhaustion. Emerging evidence highlights the existence of specific CAF subsets with distinct capabilities to modulate the immune landscape of TME in various cancers, suggesting the possibility of their exploitation as possible prognostic biomarkers and therapeutic targets.

SAP deletion promotes malignant insulinoma progression by inducing CXCL12 secretion from CAFs via the CXCR4/p38/ERK signalling pathway.

Malignant insulinoma is an extremely rare type of functioning pancreatic neuroendocrine tumour with a high degree of malignancy and a high incidence of metastasis. However, it is still unclear how malignant insulinomas develop and metastasize. Serum amyloid P component (SAP), a member of the pentraxin protein family, is an acute-phase protein secreted by liver cells. The role of SAP in insulinoma and the related mechanism are still unknown. To determine the effect of SAP on insulinoma, we crossed Rip1-Tag2 mice, which spontaneously develop insulinoma, and SAP knockout (KO) mice to generate Rip1-Tag2;SAP-/- mice. We found that SAP deletion significantly promoted the growth, invasion and metastasis of malignant insulinoma through C-X-C motif chemokine ligand 12 (CXCL12) secreted by cancer-associated fibroblasts (CAFs). Further study showed that SAP deletion promoted CXCL12 secretion by CAFs through the CXCR4/p38/ERK signalling pathway. These findings reveal a novel role and mechanism of SAP in malignant insulinoma and provide direct evidence that SAP may be a therapeutic agent for this disease.

Protection against experimental cryptococcosis elicited by Cationic Adjuvant Formulation 01-adjuvanted subunit vaccines.

The fungal infection, cryptococcosis, is responsible for >100,000 deaths annually. No licensed vaccines are available. We explored the efficacy and immune responses of subunit cryptococcal vaccines adjuvanted with Cationic Adjuvant Formulation 01 (CAF01). CAF01 promotes humoral and T helper (Th) 1 and Th17 immune responses and has been safely used in human vaccine trials. Four subcutaneous vaccines, each containing single recombinant Cryptococcus neoformans protein antigens, partially protected mice from experimental cryptococcosis. Protection increased, up to 100%, in mice that received bivalent and quadrivalent vaccine formulations. Vaccinated mice that received a pulmonary challenge with C. neoformans had an influx of leukocytes into the lung including robust numbers of polyfunctional CD4+ T cells which produced Interferon gamma (IFNγ), tumor necrosis factor alpha (TNFα), and interleukin (IL)-17 upon ex vivo antigenic stimulation. Cytokine-producing lung CD8+ T cells were also found, albeit in lesser numbers. A significant, durable IFNγ response was observed in the lungs, spleen, and blood. Moreover, IFNγ secretion following ex vivo stimulation directly correlated with fungal clearance in the lungs. Thus, we have developed multivalent cryptococcal vaccines which protect mice from experimental cryptococcosis using an adjuvant which has been safely tested in humans. These preclinical studies suggest a path towards human cryptococcal vaccine trials.

Cellular collusion: cracking the code of immunosuppression and chemo resistance in PDAC.

Despite the efforts, pancreatic ductal adenocarcinoma (PDAC) is still highly lethal. Therapeutic challenges reside in late diagnosis and establishment of peculiar tumor microenvironment (TME) supporting tumor outgrowth. This stromal landscape is highly heterogeneous between patients and even in the same patient. The organization of functional sub-TME with different cellular compositions provides evolutive advantages and sustains therapeutic resistance. Tumor progressively establishes a TME that can suit its own needs, including proliferation, stemness and invasion. Cancer-associated fibroblasts and immune cells, the main non-neoplastic cellular TME components, follow soluble factors-mediated neoplastic instructions and synergize to promote chemoresistance and immune surveillance destruction. Unveiling heterotypic stromal-neoplastic interactions is thus pivotal to breaking this synergism and promoting the reprogramming of the TME toward an anti-tumor milieu, improving thus the efficacy of conventional and immune-based therapies. We underscore recent advances in the characterization of immune and fibroblast stromal components supporting or dampening pancreatic cancer progression, as well as novel multi-omic technologies improving the current knowledge of PDAC biology. Finally, we put into context how the clinic will translate the acquired knowledge to design new-generation clinical trials with the final aim of improving the outcome of PDAC patients.

Unlocking the Hidden Pathway: A Rare Encounter With Right Coronary Artery Fistula to Coronary Sinus and Right Ventricle.

Coronary artery fistulas (CAFs) are rare vascular anomalies characterized by abnormal connections between coronary arteries and cardiac chambers or adjacent structures. Advances in cardiac interventions have led to an increasing recognition of acquired CAFs, which are typically congenital. We present a case of a 62-year-old male with a complex medical history, including hypertension, atrial fibrillation, and heart failure, who presented with exertional chest pain and palpitations. Diagnostic evaluation revealed a significant CAF originating from the right coronary artery (RCA) and terminating into the coronary sinus and right ventricle. Despite the absence of significant coronary artery occlusions, the fistula was deemed clinically significant due to its potential to cause myocardial ischemia. Management involved guideline-directed medical therapy and lifestyle modifications. This case underscores the importance of early recognition and appropriate management of CAFs to optimize patient outcomes. Further research is needed to better understand the natural history and optimal management strategies of CAFs.

Aspartate ß-Hydroxylase Is Upregulated in Head and Neck Squamous Cell Carcinoma and Regulates Invasiveness in Cancer Cell Models.

Aspartate ß-hydroxylase (ASPH) is a protein associated with malignancy in a wide range of tumors. We hypothesize that inhibition of ASPH activity could have anti-tumor properties in patients with head and neck cancer. In this study, we screened tumor tissues of 155 head and neck squamous cell carcinoma (HNSCC) patients for the expression of ASPH using immunohistochemistry. We used an ASPH inhibitor, MO-I-1151, known to inhibit the catalytic activity of ASPH in the endoplasmic reticulum, to show its inhibitory effect on the migration of SCC35 head and neck cancer cells in cell monolayers and in matrix-embedded spheroid co-cultures with primary cancer-associated fibroblast (CAF) CAF 61137 of head and neck origin. We also studied a combined effect of MO-I-1151 and HfFucCS, an inhibitor of invasion-blocking heparan 6-O-endosulfatase activity. We found ASPH was upregulated in HNSCC tumors compared to the adjacent normal tissues. ASPH was uniformly high in expression, irrespective of tumor stage. High expression of ASPH in tumors led us to consider it as a therapeutic target in cell line models. ASPH inhibitor MO-I-1151 had significant effects on reducing migration and invasion of head and neck cancer cells, both in monolayers and matrix-embedded spheroids. The combination of the two enzyme inhibitors showed an additive effect on restricting invasion in the HNSCC cell monolayers and in the CAF-containing co-culture spheroids. We identify ASPH as an abundant protein in HNSCC tumors. Targeting ASPH with inhibitor MO-I-1151 effectively reduces CAF-mediated cellular invasion in cancer cell models. We propose that the additive effect of MO-I-1151 with HfFucCS, an inhibitor of heparan 6-O-endosulfatases, on HNSCC cells could improve interventions and needs to be further explored.

Tumor cell-intrinsic epigenetic dysregulation shapes cancer-associated fibroblasts heterogeneity to metabolically support pancreatic cancer.

The tumor microenvironment (TME) in pancreatic ductal adenocarcinoma (PDAC) involves a significant accumulation of cancer-associated fibroblasts (CAFs) as part of the host response to tumor cells. The origins and functions of transcriptionally diverse CAF populations in PDAC remain poorly understood. Tumor cell-intrinsic genetic mutations and epigenetic dysregulation may reshape the TME; however, their impacts on CAF heterogeneity remain elusive. SETD2, a histone H3K36 trimethyl-transferase, functions as a tumor suppressor. Through single-cell RNA sequencing, we identify a lipid-laden CAF subpopulation marked by ABCA8a in Setd2-deficient pancreatic tumors. Our findings reveal that tumor-intrinsic SETD2 loss unleashes BMP2 signaling via ectopic gain of H3K27Ac, leading to CAFs differentiation toward lipid-rich phenotype. Lipid-laden CAFs then enhance tumor progression by providing lipids for mitochondrial oxidative phosphorylation via ABCA8a transporter. Together, our study links CAF heterogeneity to epigenetic dysregulation in tumor cells, highlighting a previously unappreciated metabolic interaction between CAFs and pancreatic tumor cells.

Stromal cartilage oligomeric matrix protein as a tumorigenic driver in ovarian cancer via Notch3 signaling and epithelial-to-mesenchymal transition.

BACKGROUND: Cartilage oligomeric matrix protein (COMP), an extracellular matrix glycoprotein, is vital in preserving cartilage integrity. Further, its overexpression is associated with the aggressiveness of several types of solid cancers. This study investigated COMP's role in ovarian cancer, exploring clinicopathological links and mechanistic insights. METHODS: To study the association of COMP expression in cancer cells and stroma with clinicopathological features of ovarian tumor patients, we analyzed an epithelial ovarian tumor cohort by immunohistochemical analysis. Subsequently, to study the functional mechanisms played by COMP, an in vivo xenograft mouse model and several molecular biology techniques such as transwell migration and invasion assay, tumorsphere formation assay, proximity ligation assay, and RT-qPCR array were performed. RESULTS: Based on immunohistochemical analysis of epithelial ovarian tumor tissues, COMP expression in the stroma, but not in cancer cells, was linked to worse overall survival (OS) of ovarian cancer patients. A xenograft mouse model showed that carcinoma-associated fibroblasts (CAFs) expressing COMP stimulate the growth and metastasis of ovarian tumors through the secretion of COMP. The expression of COMP was upregulated in CAFs stimulated with TGF-ß. Functionally, secreted COMP by CAFs enhanced the migratory capacity of ovarian cancer cells. Mechanistically, COMP activated the Notch3 receptor by enhancing the Notch3-Jagged1 interaction. The dependency of the COMP effect on Notch was confirmed when the migration and tumorsphere formation of COMP-treated ovarian cancer cells were inhibited upon incubation with Notch inhibitors. Moreover, COMP treatment induced epithelial-to-mesenchymal transition and upregulation of active ß-catenin in ovarian cancer cells. CONCLUSION: This study suggests that COMP secretion by CAFs drives ovarian cancer progression through the induction of the Notch pathway and epithelial-to-mesenchymal transition.

scRNA-seq characterizing the heterogeneity of fibroblasts in breast cancer reveals a novel subtype SFRP4+ CAF that inhibits migration and predicts prognosis.

Introduction: Cancer-associated fibroblasts (CAFs) are a diverse group of cells that significantly impact the tumor microenvironment and therapeutic responses in breast cancer (BC). Despite their importance, the comprehensive profile of CAFs in BC remains to be fully elucidated. Methods: To address this gap, we utilized single-cell RNA sequencing (scRNA-seq) to delineate the CAF landscape within 14 BC normal-tumor paired samples. We further corroborated our findings by analyzing several public datasets, thereby validating the newly identified CAF subtype. Additionally, we conducted coculture experiments with BC cells to assess the functional implications of this CAF subtype. Results: Our scRNA-seq analysis unveiled eight distinct CAF subtypes across five tumor and six adjacent normal tissue samples. Notably, we discovered a novel subtype, designated as SFRP4+ CAFs, which was predominantly observed in normal tissues. The presence of SFRP4+ CAFs was substantiated by two independent scRNA-seq datasets and a spatial transcriptomics dataset. Functionally, SFRP4+ CAFs were found to impede BC cell migration and the epithelial-mesenchymal transition (EMT) process by secreting SFRP4, thereby modulating the WNT signaling pathway. Furthermore, we established that elevated expression levels of SFRP4+ CAF markers correlate with improved survival outcomes in BC patients, yet paradoxically, they predict a diminished response to neoadjuvant chemotherapy in cases of triple-negative breast cancer. Conclusion: This investigation sheds light on the heterogeneity of CAFs in BC and introduces a novel SFRP4+ CAF subtype that hinders BC cell migration. This discovery holds promise as a potential biomarker for refined prognostic assessment and therapeutic intervention in BC.

Distinct fibroblast subpopulations associated with bone, brain or intrapulmonary metastasis in advanced non-small-cell lung cancer.

BACKGROUND: Bone or brain metastases may develop in 20-40% of individuals with late-stage non-small-cell lung cancer (NSCLC), resulting in a median overall survival of only 4-6 months. However, the primary lung cancer tissue's distinctions between bone, brain and intrapulmonary metastases of NSCLC at the single-cell level have not been underexplored. METHODS: We conducted a comprehensive analysis of 14 tissue biopsy samples obtained from treatment-naïve advanced NSCLC patients with bone (n = 4), brain (n = 6) or intrapulmonary (n = 4) metastasis using single-cell sequencing originating from the lungs. Following quality control and the removal of doublets, a total of 80 084 cells were successfully captured. RESULTS: The most significant inter-group differences were observed in the fraction and function of fibroblasts. We identified three distinct cancer-associated fibroblast (CAF) subpopulations: myofibroblastic CAF (myCAF), inflammatory CAF (iCAF) and antigen-presenting CAF (apCAF). Notably, apCAF was prevalent in NSCLC with bone metastasis, while iCAF dominated in NSCLC with brain metastasis. Intercellular signalling network analysis revealed that apCAF may play a role in bone metastasis by activating signalling pathways associated with cancer stemness, such as SPP1-CD44 and SPP1-PTGER4. Conversely, iCAF was found to promote brain metastasis by activating invasion and metastasis-related molecules, such as MET hepatocyte growth factor. Furthermore, the interaction between CAFs and tumour cells influenced T-cell exhaustion and signalling pathways within the tumour microenvironment. CONCLUSIONS: This study unveils the direct interplay between tumour cells and CAFs in NSCLC with bone or brain metastasis and identifies potential therapeutic targets for inhibiting metastasis by disrupting these critical cell-cell interactions.

Simultaneous Expression of CD70 and POSTN in Cancer-Associated Fibroblasts Predicts Worse Survival of Colorectal Cancer Patients.

Colorectal cancer (CRC) is one of the most common gastrointestinal cancers worldwide, with high morbidity and mortality rates. The evidence for the tumor-supporting capacities of cancer-associated fibroblasts (CAFs) that modulate cancer cell proliferation, invasion, metastasis, and tumor immunity, including in CRC, has been attracting attention. The present study examined the expression status of CD70 and POSTN in CRC and analyzed their association with clinicopathological features and clinical outcomes. In the present study, in total 15% (40/269) and 44% (119/269) of cases exhibited CD70 and POSTN expression on CAFs, respectively. Co-expression of CD70 and POSTN was detected in 8% (21/269) of patients. Fluorescent immunohistochemistry identified the co-expression of CD70 and POSTN with FAP and PDPN, respectively. ACTA2 was not co-expressed with CD70 or POSTN in CRC CAFs. CRC with CD70+/POSTN+ status in CAFs was significantly associated with distant organ metastasis (p = 0.0020) or incomplete resection status (p = 0.0011). CD70+/POSTN+ status tended to associate with advanced pT stage (p = 0.032) or peritoneal metastasis (p = 0.0059). Multivariate Cox hazards regression analysis identified CD70+/POSTN+ status in CAFs [hazard ratio (HR) = 3.78] as a potential independent risk factor. In vitro experiments revealed the activated phenotypes of colonic fibroblasts induced by CD70 and POSTN, while migration and invasion assays identified enhanced migration and invasion of CRC cells co-cultured with CD70- and POSTN-expressing colonic fibroblasts. On the basis of our observations, CD70 and POSTN immunohistochemistry can be used in the prognostication of CRC patients. CRC CAFs may be a promising target in the treatment of CRC patients.

Multicellular Tumoroids for Investigating Cancer Stem-Like Cells in the Heterogeneous Tumor Microenvironment.

Cancer stem-like cells (CSC) are a major contributing factor to chemoresistance, tumor recurrence, and poor survival outcomes in patients across cancer types. Signaling from non-tumor cells in the tumor microenvironment (TME) enriches for and supports CSC. This complex cell-cell signaling in the heterogeneous TME presents a challenge for patient survival; however, it also presents an opportunity to develop new targeted therapies that can inhibit survival of CSC. In this chapter, we report a multicellular tumoroid model which can be used to investigate the interactions between cancer cells and non-tumor cells in the TME to better understand the contribution of various cell types to cancer cell phenotypes, as well as the underlying mechanisms involved. The following methods allow for each cell type to be distinguished using FACS and studied individually. Gene expression can be analyzed for cancer cells, as well as the other non-tumor cells using qPCR following sorting. The response to chemotherapeutic agents and expression of stem markers can be determined for cancer cells using flow cytometry, excluding the other cell types to get an accurate view of the cancer cells. Furthermore, the viability of non-tumor cells can be analyzed as well to determine if there are cytotoxic effects of the drugs on non-tumor cells. Thus, the multicellular tumoroid model will reveal the interactions between the CSC and non-tumor cells in the heterogenous TME, resulting in discoveries in the fields of cancer biology, novel targeted therapies, and personalized drug screening for precision medicine.

KU70 and CAF-1 in Arabidopsis: Divergent roles in rDNA stability and telomere homeostasis.

Deficiency in chromatin assembly factor-1 (CAF-1) in plants through dysfunction of its components, FASCIATA1 and 2 (FAS1, FAS2), leads to the specific and progressive loss of rDNA and telomere repeats in plants. This loss is attributed to defective repair mechanisms for the increased DNA breaks encountered during replication, a consequence of impaired replication-dependent chromatin assembly. In this study, we explore the role of KU70 in these processes. Our findings reveal that, although the rDNA copy number is reduced in ku70 mutants when compared with wild-type plants, it is not markedly affected by diverse KU70 status in fas1 mutants. This is consistent with our previous characterisation of rDNA loss in fas mutants as a consequence part of the single-strand annealing pathway of homology-dependent repair. In stark contrast to rDNA, KU70 dysfunction fully suppresses the loss of telomeres in fas1 plants and converts telomeres to their elongated and heterogeneous state typical for ku70 plants. We conclude that the alternative telomere lengthening pathway, known to be activated in the absence of KU70, overrides progressive telomere loss due to CAF-1 dysfunction.

Bioengineered Hydrogels Recapitulate Fibroblast Heterogeneity in Cancer.

Recently mapped transcriptomic landscapes reveal the extent of heterogeneity in cancer-associated fibroblasts (CAFs) beyond previously established single-gene markers. Functional analyses of individual CAF subsets within the tumor microenvironment are critical to develop more accurate CAF-targeting therapeutic strategies. However, there is a lack of robust preclinical models that reflect this heterogeneity in vitro. In this study, single-cell RNA sequencing datasets acquired from head and neck squamous cell carcinoma tissues to predict microenvironmental and cellular features governing individual CAF subsets are leveraged. Some of these features are then incorporated into a tunable hyaluronan-based hydrogel system to culture patient-derived CAFs. Control over hydrogel degradability and integrin adhesiveness enabled derivation of the predominant myofibroblastic and inflammatory CAF subsets, as shown through changes in cell morphology and transcriptomic profiles. Last, using these hydrogel-cultured CAFs, microtubule dynamics are identified, but not actomyosin contractility, as a key mediator of CAF plasticity. The recapitulation of CAF heterogeneity in vitro using defined hydrogels presents unique opportunities for advancing the understanding of CAF biology and evaluation of CAF-targeting therapeutics.

A comprehensive multi-omics analysis identifies a robust scoring system for cancer-associated fibroblasts and intervention targets in colorectal cancer.

BACKGROUND: Cancer-associated fibroblasts (CAF) play a critical role in promoting tumor growth, metastasis, and immune evasion. While numerous studies have investigated CAF, there remains a paucity of research on their clinical application in colorectal cancer (CRC). METHODS: In this study, we collected differentially expressed genes between CAF and normal fibroblasts (NF) from previous CRC studies, and utilized machine learning analysis to differentiate two distinct subtypes of CAF in CRC. To enable practical application, a CAF-related genes (CAFGs) scoring system was developed based on multivariate Cox regression. We then conducted functional enrichment analysis, Kaplan-Meier plot, consensus molecular subtypes (CMS) classification, and Tumor Immune Dysfunction and Exclusion (TIDE) algorithm to investigate the relationship between the CAFGs scoring system and various biological mechanisms, prognostic value, tumor microenvironment, and response to immune checkpoint blockade (ICB) therapy. Moreover, single-cell transcriptomics and proteomics analyses have been employed to validate the significance of scoring system-related molecules in the identity and function of CAF. RESULTS: We unveiled significant distinctions in tumor immune status and prognosis not only between the CAF clusters, but also across high and low CAFGs groups. Specifically, patients in CAF cluster 2 or with high CAFGs scores exhibited higher CAF markers and were enriched for CAF-related biological pathways such as epithelial-mesenchymal transition (EMT) and angiogenesis. In addition, CAFGs score was identified as a risk index and correlated with poor overall survival (OS), progression-free survival (PFS), disease-free survival (DFS), and recurrence-free survival (RFS). High CAFGs scores were observed in patients with advanced stages, CMS4, as well as lymphatic invasion. Furthermore, elevated CAFG scores in patients signified a suppressive tumor microenvironment characterized by the upregulation of programmed death-ligand 1 (PD-L1), T-cell dysfunction, exclusion, and TIDE score. And high CAFGs scores can differentiate patients with lower response rates and poor prognosis under ICB therapy. Notably, single-cell transcriptomics and proteomics analyses identified several molecules related to CAF identity and function, such as FSTL1, IGFBP7, and FBN1. CONCLUSION: We constructed a robust CAFGs score system with clinical significance using multiple CRC cohorts. In addition, we identified several molecules related to CAF identity and function that could be potential intervention targets for CRC patients.

Enhancement of Tumorigenicity, Spheroid Niche, and Drug Resistance of Pancreatic Cancer Cells in Three-Dimensional Culture System.

The three-dimensional (3D) cell culture technique has been applied comprehensively as a variable platform for medical research, biochemical signal pathway analysis, and evaluation of anti-tumor treatment response due to an excellent recapitulation of a tumor microenvironment (TME) in the in vitro cultured cancer cells. Pancreatic cancer (PaC) is one of the toughest malignancies with a complex TME and refractory treatment response. To comprehensively study the TME of PaC, there is an eager need to develop a 3D culture model to decompose the cellular components and their cross interactions. Herein, we establish a 3D PaC culture system with cancer stem cell (CSC) and scalability properties. To validate our model, we tested the individual PaC cell and the combined effects with cancer-associated fibroblasts (CAFs) on cancer tumorigenicity, the cellular interaction through the CXCR3/CXCL10 axis, and cellular responses reflection of anti-cancer treatments. With the help of our 3D technology, a simulated malignant spheroid with important stromal populations and TME physiochemical properties may be successfully recreated. It can be used in a wide range of preclinical research and helpful in advancing basic and translational cancer biology.

Cancer-associated fibroblast spatial heterogeneity and EMILIN1 expression in the tumor microenvironment modulate TGF-ß activity and CD8+ T-cell infiltration in breast cancer.

Rationale: The tumor microenvironment (TME) and its multifaceted interactions with cancer cells are major targets for cancer treatment. Single-cell technologies have brought major insights into the TME, but the resulting complexity often precludes conclusions on function. Methods: We combined single-cell RNA sequencing and spatial transcriptomic data to explore the relationship between different cancer-associated fibroblast (CAF) populations and immune cell exclusion in breast tumors. The significance of the findings was then evaluated in a cohort of tumors (N=75) from breast cancer patients using immunohistochemistry analysis. Results: Our data show for the first time the degree of spatial organization of different CAF populations in breast cancer. We found that IL-iCAFs, Detox-iCAFs, and IFNγ-iCAFs tended to cluster together, while Wound-myCAFs, TGFß-myCAFs, and ECM-myCAFs formed another group that overlapped with elevated TGF-ß signaling. Differential gene expression analysis of areas with CD8+ T-cell infiltration/exclusion within the TGF-ß signaling-rich zones identified elastin microfibrillar interface protein 1 (EMILIN1) as a top modulated gene. EMILIN1, a TGF-ß inhibitor, was upregulated in IFNγ-iCAFs directly modulating TGFß immunosuppressive function. Histological analysis of 75 breast cancer samples confirmed that high EMILIN1 expression in the tumor margins was related to high CD8+ T-cell infiltration, consistent with our spatial gene expression analysis. High EMILIN1 expression was also associated with better prognosis of patients with breast cancer, underscoring its functional significance for the recruitment of cytotoxic T cells into the tumor area. Conclusion: Our data show that correlating TGF-ß signaling to a CAF subpopulation is not enough because proteins with TGF-ß-modulating activity originating from other CAF subpopulations can alter its activity. Therefore, therapeutic targeting should remain focused on biological processes rather than on specific CAF subtypes.

Extracellular vesicles and cancer stemness in hepatocellular carcinoma - is there a link?

Hepatocellular carcinoma (HCC) is a highly aggressive malignancy, with high recurrence rates and notorious resistance to conventional chemotherapy. Cancer stemness refers to the stem-cell-like phenotype of cancer cells and has been recognized to play important roles in different aspects of hepatocarcinogenesis. Small extracellular vesicles (sEVs) are small membranous particles secreted by cells that can transfer bioactive molecules, such as nucleic acids, proteins, lipids, and metabolites, to neighboring or distant cells. Recent studies have highlighted the role of sEVs in modulating different aspects of the cancer stemness properties of HCC. Furthermore, sEVs derived from diverse cellular sources, such as cancer cells, stromal cells, and immune cells, contribute to the maintenance of the cancer stemness phenotype in HCC. Through cargo transfer, specific signaling pathways are activated within the recipient cells, thus promoting the stemness properties. Additionally, sEVs can govern the secretion of growth factors from non-cancer cells to further maintain their stemness features. Clinically, plasma sEVs may hold promise as potential biomarkers for HCC diagnosis and treatment prediction. Understanding the underlying mechanisms by which sEVs promote cancer stemness in HCC is crucial, as targeting sEV-mediated communication may offer novel strategies in treatment and improve patient outcome.

Melanoma-associated fibroblasts in tumor-promotion flammation and antitumor immunity: novel mechanisms and potential immunotherapeutic strategies.

Melanoma, renowned for its aggressive behavior and resistance to conventional treatments, stands as a formidable challenge in the oncology landscape. The dynamic and complex interplay between cancer cells and the tumor microenvironment has gained significant attention, revealing Melanoma-Associated Fibroblasts (MAFs) as central players in disease progression. The heterogeneity of MAFs endows them with a dual role in melanoma. This exhaustive review seeks to not only shed light on the multifaceted roles of MAFs in orchestrating tumor-promoting inflammation but also to explore their involvement in antitumor immunity. By unraveling novel mechanisms underlying MAF functions, this review aims to provide a comprehensive understanding of their impact on melanoma development. Additionally, it delves into the potential of leveraging MAFs for innovative immunotherapeutic strategies, offering new avenues for enhancing treatment outcomes in the challenging realm of melanoma therapeutics.