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Cancer‐associated fibroblasts (CAFs) contribute to the progression of lung cancer. Four and a half LIM domain protein‐2 (FHL2) is a component of focal adhesion structures. We analyzed the function of FHL2 expressed by CAFs in lung adenocarcinoma. Expression of FHL2 in fibroblast subtypes was investigated using database of single‐cell RNA‐sequencing of lung cancer tissue. The role of FHL2 in the proliferation and migration of CAFs was assessed. The effects of FHL2 knockout on the migration and invasion of human lung adenocarcinoma cells and tube formation of endothelial cells induced by CAF‐conditioned medium (CM) were evaluated. The effect of FHL2 knockout in CAFs on metastasis was determined using a murine orthotopic lung cancer model. The prognostic significance of stromal FHL2 was assessed by immunohistochemistry in human adenocarcinoma specimens. FHL2 is highly expressed in myofibroblasts in cancer tissue. TGF‐β1 upregulated FHL2 expression in CAFs and FHL2 knockdown attenuated CAF proliferation. FHL2 knockout reduced CAF induced migration of A110L and H23 human lung adenocarcinoma cell lines, and the induction of tube formation of endothelial cells. FHL2 knockout reduced CAF‐induced metastasis of lung adenocarcinomas in an orthotopic model in vivo. The concentration of Osteopontin (OPN) in CM from CAF was downregulated by FHL2 knockout. siRNA silencing and antibody blocking of OPN reduced the pro‐migratory effect of CM from CAF on lung cancer cells. In resected lung adenocarcinoma specimens, positive stromal FHL2 expression was significantly associated with higher microvascular density and worse prognosis. In conclusion, FHL2 expression by CAFs enhances the progression of lung adenocarcinoma by promoting angiogenesis and metastasis. [ABSTRACT FROM AUTHOR]

Background: Gastric cancer (GC) remains a significant cause of cancer-related mortality worldwide. Despite the transformative impact of immune checkpoint blockade (ICB) therapies across various cancers, only a minority of patients with metastatic GC (mGC) benefit, emphasizing the urgent need for precise biomarkers to predict therapeutic responses and optimize patient selection. Methods: In this multi-omics study, we conducted whole exome and transcriptome sequencing on 12 tumors from mGC patients treated with nivolumab as first-line therapy. To validate our findings, we performed whole transcriptome sequencing on 17 additional tumors and analyzed 45 tumors from public dataset (PRJEB25780) of patients who received ICB therapy as second or third-line treatment. Comprehensive multi-omics analyses were conducted using single-cell RNA sequencing (n = 5, GSE167297) and spatial transcriptome sequencing (n = 2, independent internal dataset). Results: ICB-sensitive tumors exhibited robust activation of the interferon response pathway, while ICB-resistant tumors displayed epithelial–mesenchymal transition signatures. Intriguingly, at the single-cell level, genes associated with ICB sensitivity were predominantly expressed in immune cells, whereas genes associated with resistance were primarily found in cancer-associated fibroblasts (CAFs), particularly the desmoplastic CAF (dCAF) subtype. We identified DCN as a hallmark dCAF marker, and high DCN expression was inversely correlated with PD-L1 levels, ICB resistance, and poor prognosis in mGC (log-rank p = 0.027). Conclusion: This study elucidates the critical influence of the tumor microenvironment, specifically dCAFs, in mediating ICB resistance in mGC. Our findings highlight DCN as a representative marker for dCAF and a promising negative predictive biomarker for ICB response. These findings highlight the complex stromal-immune interactions and open avenues for personalized treatment for mGC. [ABSTRACT FROM AUTHOR]

Cancer‐associated fibroblasts (CAFs) are the dominant nonmalignant component of the tumour microenvironment (TME). CAFs demonstrate a high level of inter‐ and intra‐tumour heterogeneity in solid tumours, though the drivers of CAF subpopulations are not fully understood. Here, we demonstrate that non‐small cell lung cancer (NSCLC) patient‐derived CAFs upregulate the secretion of inflammatory cytokines (IL6, LIF, IL33, GM‐CSF, IL1ra) and chemokines (CCL2, CCL3, CCL4, CCL20, CXCL8, CXCL9, CXCL10, CXCL11) in response to in vitro co‐culture with anti‐CD3/anti‐CD28‐stimulated peripheral blood mononuclear cells (PBMCs) via IFNγ and TNFα. Furthermore, T‐cell‐derived IFNγ inhibits CXCL12 secretion by CAFs in vitro. Our results highlight the ability of T‐cell effector cytokines to modulate the CAF secretome in NSCLC. [ABSTRACT FROM AUTHOR]

Objectives: Podoplanin (PDPN) expression in cancer‐associated fibroblasts (CAFs) (CAF‐PDPN) is considered a poor prognostic factor in nonsmall cell lung cancer, but little is known about its clinical significance in high‐grade neuroendocrine carcinoma of the lung (HGNEC). This study examines the association between CAF‐PDPN and stromal programmed death‐ligand 1 (PD‐L1) expression and the prognostic implications of CAF‐PDPN and PD‐L1 expression status in surgically resected HGNEC patients. Methods: Immunohistochemical analyses were performed on 121 resected HGNEC specimens using antibodies against PDPN and PD‐L1. Correlations between CAF‐PDPN, stromal PD‐L1 expression, and clinicopathologic features and their implications for survival were analyzed statistically. Results: There were substantially more large‐cell neuroendocrine carcinomas in the stromal PD‐L1‐positive group and more vascular invasion in the tumoral PD‐L1‐positive group. PDPN expression in CAF was moderately correlated with stromal PD‐L1 expression (ρ = 0.567, p < 0.001). In a survival analysis combining CAF‐PDPN and stromal PD‐L1 status, the 5‐year RFS rates for Group A: CAF‐PDPN (+)/stromal PD‐L1 (+), Group B: CAF‐PDPN (+)/stromal PD‐L1 (−), Group C: CAF‐PDPN (−)/stromal PD‐L1 (+), and Group D: CAF‐PDPN (−)/stromal PD‐L1 (−) were 62.0%, 46.8%, 17.5%, and 20.2%, respectively, with corresponding 5‐year OS rates of 76.6%, 69.2%, 27.0%, and 25.3%. The log‐rank test showed statistically significant differences among the groups in RFS (p < 0.001) and OS (p < 0.001). Conclusions: There is a correlation between CAF‐PDPN and tumoral/stromal PD‐L1 expression, and positive status for either CAF‐PDPN or stromal PD‐L1 expression could be an independent favorable prognostic factor in surgically resected HGNEC patients. [ABSTRACT FROM AUTHOR]

Simple Summary: Peritoneal metastasis, where cancer spreads to the lining of the abdomen, is a serious issue for patients with gastric cancer and often affects adipose-rich areas like the omentum. This study explores whether stem cells from the omentum contribute to peritoneal metastasis by becoming members of the cancer microenvironment and affecting cancer stem cells. By examining how these stem cells interact with gastric cancer cells, this study finds that they can promote peritoneal metastasis and resistance to treatment. These findings lead to new strategies for targeting omentum-derived stem cells to improve treatment outcomes for patients with peritoneal metastasis. Background: Peritoneal metastasis (PM) remains a major challenge in patients with gastric cancer (GC) and occurs preferentially in adipose-rich organs, such as the omentum. Adipose-derived stem cells (ASCs) may influence cancer behavior. This study aimed to investigate whether ASCs isolated from the omentum can act as progenitors of cancer-associated fibroblasts (CAFs) and analyze their effects on the cancer stem cell (CSC) niche and the treatment resistance of GC cells. Methods: ASCs were isolated from the human omentum and their cellular characteristics were analyzed during co-culturing with GC cells. Results: ASCs express CAF markers and promote desmoplasia in cancer stroma in a mouse xenograft model. When co-cultured with GC cells, ASCs enhanced the sphere-forming efficiency of MKN45 and MKN74 cells. ASCs increased IL-6 secretion and enhanced the expression of Nanog and CD44v6 in GC cells; however, these changes were suppressed by the inhibition of IL-6. Xenograft mouse models co-inoculated with MKN45 cells and ASCs showed enhanced CD44v6 and Nanog expression and markedly reduced apoptosis induced by 5-FU treatment. Conclusion: This study improves our understanding of ASCs' role in PM treatment resistance and has demonstrated the potential for new treatment strategies targeting ASCs. [ABSTRACT FROM AUTHOR]

Aberrant expression of repeat RNAs in pancreatic ductal adenocarcinoma (PDAC) mimics viral-like responses with implications on tumor cell state and the response of the surrounding microenvironment. To better understand the relationship of repeat RNAs in human PDAC, we performed spatial molecular imaging at single-cell resolution in 46 primary tumors, revealing correlations of high repeat RNA expression with alterations in epithelial state in PDAC cells and myofibroblast phenotype in cancer-associated fibroblasts (CAFs). This loss of cellular identity is observed with dosing of extracellular vesicles (EVs) and individual repeat RNAs of PDAC and CAF cell culture models pointing to cell-cell intercommunication of these viral-like elements. Differences in PDAC and CAF responses are driven by distinct innate immune signaling through interferon regulatory factor 3 (IRF3). The cell-context-specific viral-like responses to repeat RNAs provide a mechanism for modulation of cellular plasticity in diverse cell types in the PDAC microenvironment. [Display omitted] • Single-molecule imaging provides a spatial map of repeat and coding RNAs in human PDAC • Interferon response to repeat RNAs perturbs multiple cell types in PDAC tumor • Repeat RNA delivery to stromal cells via extracellular vesicles analogous to a virus • Divergent responses to repeat RNAs between CAFs and PDAC cells are driven by IRF3 Single-molecule spatial imaging in human pancreatic cancers identifies aberrant repeat RNA expression in cancer cells and the surrounding tumor microenvironment linked with alterations in cell fate induced by an interferon response to the viral-like behavior of repeat elements. [ABSTRACT FROM AUTHOR]

• Integrin α11β1 locates in fibrillar adhesions in fibroblast, but not α2β1. • Integrin α11β1 translocation into fibrillar adhesions is tensin-1 dependent. • α5β1 and α11β1 integrins are in same fibrillar adhesions but do not overlap. • Integrin α11β1 contributes to cell surface-associated collagen I assembly. Solid epithelial cancers with significant desmoplasia are characterized by an excessive deposition of collagen-based matrix, which often supports tumor progression. However, the mechanism of how collagen receptors mediate collagen fibrillogenesis still remains mostly unclear. We show that the collagen-binding integrin α11β1 can co-localize with tensin-1 and deposited collagen I in human pancreatic ductal adenocarcinoma (PDAC) stroma. In addition to the canonical fibrillar adhesion integrin α5β1 expressed by human PDAC cancer-associated fibroblasts (CAFs), tensin-1-positive fibrillar adhesions contained α11β1 but lacked α1β1 and α2β1. CAFs lacking α5β1 expression displayed mechanoregulated and tensin-1 dependent α11β1 fibrillar adhesions, suggesting independent roles of the two integrins with regards to fibrillar adhesions-based de novo fibrillogenesis. Further, we demonstrate that cell surface-associated collagen I assembly necessitated α11β1, but not α5β1 expression. In summary, α11β1 integrin is a novel component of fibrillar adhesions, which is strategically positioned to mediate de novo collagen fibrillogenesis at the cell surface under pro-fibrotic conditions. [ABSTRACT FROM AUTHOR]

Cancer-associated fibroblasts (CAFs) exhibit remarkable phenotypic heterogeneity, with specific subsets implicated in immunosuppression in various malignancies. However, whether and how they attenuate anti-tumor immunity in gastric cancer (GC) remains elusive. CPT1C, a unique isoform of carnitine palmitoyltransferase pivotal in regulating fatty acid oxidation, is briefly indicated as a protumoral metabolic mediator in the tumor microenvironment (TME) of GC. In the present study, we initially identified specific subsets of fibroblasts exclusively overexpressing CPT1C, hereby termed them as CPT1C+CAFs. Subsequent findings indicated that CPT1C+CAFs fostered a stroma-enriched and immunosuppressive TME as they correlated with extracellular matrix-related molecular features and enrichment of both immunosuppressive subsets, especially M2-like macrophages, and multiple immune-related pathways. Next, we identified that CPT1C+CAFs promoted the M2-like phenotype of macrophage in vitro. Bioinformatic analyses unveiled the robust IL-6 signaling between CPT1C+CAFs and M2-like phenotype of macrophage and identified CPT1C+CAFs as the primary source of IL-6. Meanwhile, suppressing CPT1C expression in CAFs significantly decreased IL-6 secretion in vitro. Lastly, we demonstrated the association of CPT1C+CAFs with therapeutic resistance. Notably, GC patients with high CPT1C+CAFs infiltration responded poorly to immunotherapy in clinical cohort. Collectively, our data not only present the novel identification of CPT1C+CAFs as immunosuppressive subsets in TME of GC, but also reveal the underlying mechanism that CPT1C+CAFs impair tumor immunity by secreting IL-6 to induce the immunosuppressive M2-like phenotype of macrophage in GC. [ABSTRACT FROM AUTHOR]

Abstract Ferroptosis is a type of regulated cell death characterized by its non-apoptotic, iron-dependent and oxidative nature. Since its discovery in 2012, extensive research has demonstrated its pivotal roles in tumorigenesis, metastasis and cancer therapy. The tumor microenvironment (TME) is a complex ecosystem comprising cancer cells, non-cancer cells, extracellular matrix, metabolites and cytokines. Recent studies have underscored a new paradigm in which non-cancer cells in the TME, such as immune and stromal cells, also play significant roles in regulating tumor progression and therapeutic resistance typically through complicated crosstalk with cancer cells. Notably, this crosstalk in the TME were partially mediated through ferrotopsis-related mechanisms. This review provides a comprehensive and systematic summary of the current findings concerning the roles of ferroptosis in the TME and how ferroptosis-mediated TME reprogramming impacts cancer therapeutic resistance and progression. Additionally, this review outlines various ferroptosis-related therapeutic strategies aimed at targeting the TME.

Abstract Background Stromal fibrosis is highly associated with therapeutic resistance and poor survival in esophageal squamous cell carcinoma (ESCC) patients. Low expression of plasma gelsolin (pGSN), a serum abundant protein, has been found to correlate with inflammation and fibrosis. Here, we evaluated pGSN expression in patients with different stages of cancer and therapeutic responses, and delineated the molecular mechanisms involved to gain insight into therapeutic strategies for ESCC. Methods Circulating pGSN level in ESCC patients was determined by enzyme-linked immunosorbent assay analysis, and the tissue microarray of tumors was analyzed by immunohistochemistry staining. Cell-based studies were performed to investigate cancer behaviors and molecular mechanisms, and mouse models were used to examine the pGSN-induced tumor suppressive effects in vivo. Results Circulating pGSN expression is distinctively decreased during ESCC progression, and low pGSN expression correlates with poor therapeutic responses and poor survival. Methylation-specific PCR analysis confirmed that decreased pGSN expression is partly attributed to the hypermethylation of the GSN promoter, the gene encoding pGSN. Importantly, cell-based immunoprecipitation and protein stability assays demonstrated that pGSN competes with oncogenic tenascin-C (TNC) for the binding and degradation of integrin αvβ3, revealing that decreased pGSN expression leads to the promotion of oncogenic signaling transduction in cancer cells and fibroblasts. Furthermore, overexpression of pGSN caused the attenuation of TNC expression and inactivation of cancer-associated fibroblast (CAF), thereby leading to tumor growth inhibition in mice. Conclusions Our results demonstrated that GSN methylation causes decreased secretion of pGSN, leading to integrin dysregulation, oncogenic TNC activation, and CAF formation. These findings highlight the role of pGSN in therapeutic resistance and the fibrotic tumor microenvironment of ESCC.

Ferroptosis is a type of regulated cell death characterized by its non-apoptotic, iron-dependent and oxidative nature. Since its discovery in 2012, extensive research has demonstrated its pivotal roles in tumorigenesis, metastasis and cancer therapy. The tumor microenvironment (TME) is a complex ecosystem comprising cancer cells, non-cancer cells, extracellular matrix, metabolites and cytokines. Recent studies have underscored a new paradigm in which non-cancer cells in the TME, such as immune and stromal cells, also play significant roles in regulating tumor progression and therapeutic resistance typically through complicated crosstalk with cancer cells. Notably, this crosstalk in the TME were partially mediated through ferrotopsis-related mechanisms. This review provides a comprehensive and systematic summary of the current findings concerning the roles of ferroptosis in the TME and how ferroptosis-mediated TME reprogramming impacts cancer therapeutic resistance and progression. Additionally, this review outlines various ferroptosis-related therapeutic strategies aimed at targeting the TME. [ABSTRACT FROM AUTHOR]

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

In the development of colorectal cancer (CRC), cancer-associated fibroblasts (CAFs) play a pivotal role in establishing tumor-permissive extracellular matrix structures, angiogenesis, and modulating the immune status of the tumor microenvironment (TME), thereby influencing tumor metastasis and resistance to radiotherapy and chemotherapy. The pleiotropic effects of CAFs in the TME may be attributed to the heterogeneous origin and high plasticity of their population. Given the specificity of CAFs, they provide a variety of potential target molecules for future CRC treatment, which may play an indispensable role in CRC therapeutic strategies. This review summarizes the origin of CAFs and their roles in the CRC tumor microenvironment, including the interaction between exosomes and CAFs in CRC. Additionally, we discuss potential therapeutic strategies targeting CAFs. [ABSTRACT FROM AUTHOR]

Objective: To assess the utility of tumor-intrinsic and cancer-associated fibroblast (CAF) subtypes of pancreatic ductal adenocarcinoma (PDAC) in predicting response to neoadjuvant therapy (NAT) and overall survival (OS). Background: PDAC remains a deadly disease with limited treatment options, and both the tumor as well as the microenvironment play an important role in pathogenesis. Gene expression--based tumorintrinsic subtypes (classical and basal-like) have been shown to predict outcomes, but tumor microenvironment subtypes are still evolving. Methods: RNA-sequencing was performed on 114 deidentified resected PDAC tumors. Clinical data were collected by retrospective chart review. Single sample classifiers were used to determine classical and basal-like subtypes as well as tumor-permissive permCAF and tumor-restraining restCAF subtypes. Survival was analyzed using the log-rank test. Results: Patients who received NAT had an increase in OS, with a median survival of 27.9 months compared with 20.1 months for those who did not receive NAT, but the difference did not reach statistical significance (hazard ratio: 0.64, P=0.076). Either tumorintrinsic or CAF subtypes alone were associated with OS regardless of NAT or no NAT, and patients with classical or restCAF subtypes had the best outcomes. When evaluated together, patients with the classical-restCAF subtype had the best OS and basalpermCAF the worst OS (P< 0.0001). Patients undergoing NAT with the classical-restCAF subtype demonstrated the longest OS compared with the other groups (P=0.00041). Conclusions: CAF subtypes have an additive effect over tumorintrinsic subtypes in predicting survival with or without neoadjuvant FOLFIRINOX in PDAC. Molecular subtyping of both tumor and CAF compartments of PDAC may be important steps in selecting first-line systemic therapy. [ABSTRACT FROM AUTHOR]

Background: Stromal fibrosis is highly associated with therapeutic resistance and poor survival in esophageal squamous cell carcinoma (ESCC) patients. Low expression of plasma gelsolin (pGSN), a serum abundant protein, has been found to correlate with inflammation and fibrosis. Here, we evaluated pGSN expression in patients with different stages of cancer and therapeutic responses, and delineated the molecular mechanisms involved to gain insight into therapeutic strategies for ESCC. Methods: Circulating pGSN level in ESCC patients was determined by enzyme-linked immunosorbent assay analysis, and the tissue microarray of tumors was analyzed by immunohistochemistry staining. Cell-based studies were performed to investigate cancer behaviors and molecular mechanisms, and mouse models were used to examine the pGSN-induced tumor suppressive effects in vivo. Results: Circulating pGSN expression is distinctively decreased during ESCC progression, and low pGSN expression correlates with poor therapeutic responses and poor survival. Methylation-specific PCR analysis confirmed that decreased pGSN expression is partly attributed to the hypermethylation of the GSN promoter, the gene encoding pGSN. Importantly, cell-based immunoprecipitation and protein stability assays demonstrated that pGSN competes with oncogenic tenascin-C (TNC) for the binding and degradation of integrin αvβ3, revealing that decreased pGSN expression leads to the promotion of oncogenic signaling transduction in cancer cells and fibroblasts. Furthermore, overexpression of pGSN caused the attenuation of TNC expression and inactivation of cancer-associated fibroblast (CAF), thereby leading to tumor growth inhibition in mice. Conclusions: Our results demonstrated that GSN methylation causes decreased secretion of pGSN, leading to integrin dysregulation, oncogenic TNC activation, and CAF formation. These findings highlight the role of pGSN in therapeutic resistance and the fibrotic tumor microenvironment of ESCC. [ABSTRACT FROM AUTHOR]

Colon cancer is a global health challenge. This research is designed to build a prognostic model that can personalize the guidance of immunotherapy among colon cancer patients. Coagulation-associated prognostic genes which were subsequently integrated into a Least Absolute Shrinkage and Selection Operator algorithm for constructing a prognostic model were identified with the univariate Cox analyses. The potential of coagulation-related risk score (CRRS) in prognosis and immunotherapy outcomes was rigorously assessed. Finally, the cellular origin of genes in the CRRS model was explored with single-cell RNA-seq data, and the biological functions of core genes were further confirmed by cell function experiments. Our findings showed the CRRS model usefully classified patients into high-risk and low-risk groups. High-risk patients exhibited worse total survival. A nomogram was subsequently devised, enabling quantitative survival prediction by incorporating CRRS, age, sex, and TNM stage. Moreover, the CRRS model predicted the extent of cancer-associated fibroblasts (CAFs) infiltration. The analysis further indicated diminished immune responsiveness in high-risk patients, and single-cell data analysis pinpointed TIMP1+ CAF as a potential contributor to cancer progression. The CRRS model can be adopted as a prognostic device for colon cancer patients and low-risk patients are more suitable for treatment with immune checkpoint inhibitors. TIMP1 secreted by CAF can promote the malignant progression of colon cancer. [ABSTRACT FROM AUTHOR]

Purpose: Cancer-associated fibroblasts (CAFs) are one of the most critical cells in the tumor environment, with crucial roles in cancer progression and metastasis. Due to Field-Effect phenomena (also called field cancerization), the adjacent cavity side area of the margin is histologically normal, but it has been entered into neoplastic transformation due to MCT4 and MCT1 pathways activated by H2O2/ROS oxidative stress agents secreted by CAF in adjacent tumor bed microenvironment. This paper specifically focused on the role of cancer-associated fibroblast in breast tumor beds and its correlation with the presence of scattered cancer cells or onco-protein-activated cells (may be high risk but not completely transformed cancer cells) in the cavity side margins. Methods: In this study, the glycolytic behavior of non-tumoral cavity side margins was examined using carbon nanotube-based electrochemical biosensors integrated into a cancer diagnostic probe. This method enabled the detection of CAF accumulation sites in non-cancerous neighboring tissues of tumors, with a correlation to CAF concentration. Subsequently, RT-PCR, fluorescent, histopathological, and invasion assays were conducted on hyperglycolytic lesions to explore any correlation between the abundance of CAFs and the electrochemical responses of the non-cancerous tissues surrounding the tumor, as well as their neoplastic potential. Results: We observed overexpression of cancer-associated transcriptomes as well as the presence and hyperactivation of CAFs in cavity-side regions in which glycolytic metabolism was recorded, independent of the histopathological state of the lesion. At mean 70.4%, 66.7%, 70.4%, and 44.5% increments were observed in GLUT-1, MMP-2, N-cadherin, and MMP-9 transcriptomes by highly glycolytic but histologically cancer-free expression samples in comparison with negative controls (histologically non-cancer lesions with low glycolytic behavior). Conclusion: The presence of CAFs is correlated with the presence of high glycolytic metabolism in the cavity margin lesion, high ROS level in the lesion, and finally aggressive cancer-associated proteins (such as MMP2, …) in the margin while these metabolomes, molecules, and proteins are absent in the margins with negatively scored CDP response and low ROS level. So, it seems that when we observe CAFs in glycolytic lesions with high ROS levels, some high-risk epithelial breast cells may exist while no histological trace of cancer cells was observed. Further research on CAFs could provide valuable insights into the local recurrence of malignant breast diseases. Hence, real-time sensors can be used to detect and investigate CAFs in the non-tumoral regions surrounding tumors in cancer patients, potentially aiding in the prevention of cancer recurrence. [ABSTRACT FROM AUTHOR]

Mesoporous silica nanoparticles (MSNs) have emerged as promising drug carriers that can facilitate targeted anticancer drug delivery, but efficiency studies relying on active targeting mechanisms remain elusive. This study implements in vitro 3D cocultures, so‐called microtissues, to model a physiologically relevant tumor microenvironment (TME) to examine the impact of surface‐modified MSNs without targeting ligands on the internalization, cargo delivery, and cargo release in tumor cells and cancer‐associated fibroblasts. Among these, acetylated MSNs most effectively localized in tumor cells in a 3D setting containing collagen, while other MSNs did so to a lesser degree, most likely due to remaining trapped in the extracellular matrix of the TME. Confocal imaging of hydrophobic model drug‐loaded MSNs demonstrated effective cargo release predominantly in tumor cells, both in 2D and 3D cocultures. MSN‐mediated delivery of an anticancer drug in the microtissues exhibited a significant reduction in tumor organoid size and enhanced the tumor‐specific cytotoxic effects of a γ‐secretase inhibitor, compared to the highly hydrophobic drug in free form. This inherent targeting potential suggests reduced off‐target effects and increased drug efficacy, showcasing the promise of surface modification of MSNs as a means of direct cell‐specific targeting and delivery for precise and successful targeted drug delivery. [ABSTRACT FROM AUTHOR]

Exosomes secreted by cancer-associated fibroblasts (CAFs) play a critical part in cancer progression. This study aimed to explore the effects of CAF-exosomes on gastric cancer (GC) cell metastasis. AGS and HGC-27 cells were treated with exosomes and cell viability, migration, and invasion were evaluated using Cell-Counting Kit-8 and Transwell assays. Exosome-regulated mRNAs were explored using quantitative real-time PCR. The relationship between interleukin (IL)32 and estrogen receptor 1 (ESR1) was evaluated using co-immunoprecipitation and dual-luciferase reporter assays. The results of this study show that CAF-derived exosomes promote GC cell viability, migration, and invasion. Exosome treatment increased the levels of IL32, which interacted with ESR1 and negatively regulated ESR1 levels. Rescue experiments were conducted to demonstrate that CAF-exosomes promoted biological behaviors of GC cells by upregulating IL32 and downregulating ESR1 expression. In conclusion, CAF-derived exosomes promote GC cell viability, migration, and invasion by elevating the IL32/ESR1 axis, suggesting a novel strategy for metastatic GC treatment. [ABSTRACT FROM AUTHOR]

Bladder cancer was one of the most common carcinomas around the world. However, the mechanism of the disease still remained to be investigated. We expected to establish a prognostic survival model with 9 prognostic genes to predict overall survival (OS) in patients of bladder cancer. The gene expression data of bladder cancer were obtained from TCGA and GEO datasets. TCGA and GEO datasets were used for screening prognostic genes along with developing and validating a 9-gene prognostic survival model by method of weighted gene co-expression network analysis (WGCNA) and LASSO with Cox regression. The relative analysis of evaluate tumor burden mutation (TBM), GO, KEGG, chemotherapy drug and functional pathway were also performed based on CAF-related mRNAs. 151 Overlapping CAF-related genes were distinguished after intersecting differentially expressed genes from 945 genes in TCGA and 491 genes in GEO dataset. 9 Prognostic genes (MSRB2, AGMAT, KLF6, DDAH2, GADD45B, SERPINE2, STMN3, TEAD2, and COMP) were used for construction of prognostic model after LASSO with Cox regression. Receiver operating characteristic (ROC) curves showed a good survival prediction by this model. Functional analysis indicated chemokine, cytokine, ECM interaction, oxidative stress and apoptosis were highly appeared. Potential drugs targeted different CAF-related genes like vemurafenib, irofulven, ghiotepa, and idarubicin were found as well. We constructed a novel 9 CAF-related mRNAs prognostic model and explored the gene expression and potential functional information of related genes, which might be worthy of clinical application. In addition, potential chemotherapy drugs could provide useful insights into the potential clinical treatment of bladder cancer. [ABSTRACT FROM AUTHOR]

Cancer-associated fibroblasts (CAFs) can interact with macrophages in the tumor microenvironment by secreting extracellular vesicles (EVs), thereby affecting tumor progression. However, the mechanisms of CAF-secreted EVs in gastric cancer (GC) remain not well understood. Here, we investigated the effect of CAF-EVs on macrophage polarization in GC and the underlying mechanisms. Macrophage polarization was evaluated using flow cytometry and quantitative real-time polymerase chain reaction. GC cell proliferation was determined using cell counting kit-8, EdU, and colony formation assays. The molecular mechanism was explored using microarray analysis, dual-luciferase reporter assay, and RNA pull-down analysis. The results showed that CAFs secreted EVs that inhibit macrophage M1 polarization and promote M2 polarization. Moreover, miR-4253 expression was increased in CAF-EVs, and inhibition of miR-4253 reversed the macrophage polarization induced by EVs. IL6R was identified as the target of miR-4253. Additionally, macrophages treated with EVs that encapsulated miR-4253 promote GC cell proliferation. In conclusion, CAF-secreted EVs packaging miR-4253 facilitate macrophage polarization from M1 to M2 phenotype by targeting IL6R, thereby accelerating GC cell proliferation. The findings suggest that EV-encapsulated miR-4253 may be a promising therapeutic target of GC.

Abstract Background Cancer-associated fibroblasts (CAFs) are the prominent cell type in the tumor microenvironment (TME), and CAF subsets have been identified in various tumors. However, how CAFs spatially coordinate other cell populations within the liver TME to promote cancer progression remains unclear. Methods We combined multi-region proteomics (6 patients, 24 samples), 10X Genomics Visium spatial transcriptomics (11 patients, 25 samples), and multiplexed imaging (92 patients, 264 samples) technologies to decipher the expression heterogeneity, functional diversity, spatial distribution, colocalization, and interaction of fibroblasts. The newly identified CAF subpopulation was validated by cells isolated from 5 liver cancer patients and in vitro functional assays. Results We identified a liver CAF subpopulation, marked by the expression of COL1A2, COL4A1, COL4A2, CTGF, and FSTL1, and named F5-CAF. F5-CAF is preferentially located within and around tumor nests and colocalizes with cancer cells with higher stemness in hepatocellular carcinoma (HCC). Multiplexed staining of 92 patients and the bulk transcriptome of 371 patients demonstrated that the abundance of F5-CAFs in HCC was associated with a worse prognosis. Further in vitro experiments showed that F5-CAFs isolated from liver cancer patients can promote the proliferation and stemness of HCC cells. Conclusions We identified a CAF subpopulation F5-CAF in liver cancer, which is associated with cancer stemness and unfavorable prognosis. Our results provide potential mechanisms by which the CAF subset in the TME promotes the development of liver cancer by supporting the survival of cancer stem cells.

Abstract Cancer-associated fibroblasts (CAFs), integral components of the tumor microenvironment, play a pivotal role in tumor proliferation, metastasis, and clinical outcomes. However, its specific roles in Kidney Renal Clear Cell Carcinoma (KIRC) remain poorly understood. Employing the established Seurat single-cell analysis pipeline, we identified 21 CAFs marker genes. Subsequently, a prognostic signature consisting of 6 CAFs marker genes (RGS5, PGF, TPM2, GJA4, SEPT4, and PLXDC1) was developed in a cohort through univariate and LASSO Cox regression analyses. The model’s efficacy was then validated in an external cohort, with a remarkable predictive performance in 1-, 3-, and 5-year. Patients in the high-risk group exhibited significantly inferior survival outcomes (p

Colorectal cancer, the third most commonly occurring tumor worldwide, poses challenges owing to its high mortality rate and persistent drug resistance in metastatic cases. We investigated the tumor microenvironment, emphasizing the role of cancer-associated fibroblasts in the progression and chemoresistance of colorectal cancer. We used an indirect co-culture system comprising colorectal cancer organoids and cancer-associated fibroblasts to simulate the tumor microenvironment. Immunofluorescence staining validated the characteristics of both organoids and fibroblasts, showing high expression of epithelial cell markers (EPCAM), colon cancer markers (CK20), proliferation markers (KI67), and fibroblast markers (VIM, SMA). Transcriptome profiling was conducted after treatment with anticancer drugs, such as 5-fluorouracil and oxaliplatin, to identify chemoresistance-related genes. Changes in gene expression in the co-cultured colorectal cancer organoids following anticancer drug treatment, compared to monocultured organoids, particularly in pathways related to interferon-alpha/beta signaling and major histocompatibility complex class II protein complex assembly, were identified. These two gene groups potentially mediate drug resistance associated with JAK/STAT signaling. The interaction between colorectal cancer organoids and fibroblasts crucially modulates the expression of genes related to drug resistance. These findings suggest that the interaction between colorectal cancer organoids and fibroblasts significantly influences gene expression related to drug resistance, highlighting potential biomarkers and therapeutic targets for overcoming chemoresistance. Enhanced understanding of the interactions between cancer cells and their microenvironment can lead to advancements in personalized medical research..

Abstract Background Triple-negative breast cancer (TNBC) is characterized by its high metastatic potential, which results in poor patient survival. Cancer-associated fibroblasts (CAFs) are crucial in facilitating TNBC metastasis via induction of mitochondrial biogenesis. However, how to inhibit CAF-conferred mitochondrial biogenesis is still needed to explore. Methods We investigated metastasis using wound healing and cell invasion assays, 3D-culture, anoikis detection, and NOD/SCID mice. Mitochondrial biogenesis was detected by MitoTracker green FM staining, quantification of mitochondrial DNA levels, and blue-native polyacrylamide gel electrophoresis. The expression, transcription, and phosphorylation of peroxisome-proliferator activated receptor coactivator 1α (PGC-1α) were detected by western blotting, chromatin immunoprecipitation, dual-luciferase reporter assay, quantitative polymerase chain reaction, immunoprecipitation, and liquid chromatography-tandem mass spectrometry. The prognostic role of PGC-1α in TNBC was evaluated using the Kaplan–Meier plotter database and clinical breast cancer tissue samples. Results We demonstrated that PGC-1α indicated lymph node metastasis, tumor thrombus formation, and poor survival in TNBC patients, and it was induced by CAFs, which functioned as an inducer of mitochondrial biogenesis and metastasis in TNBC. Shikonin impeded the CAF-induced PGC-1α expression, nuclear localization, and interaction with estrogen-related receptor alpha (ERRα), thereby inhibiting PGC-1α/ERRα-targeted mitochondrial genes. Mechanistically, the downregulation of PGC-1α was mediated by synthase kinase 3β-induced phosphorylation of PGC-1α at Thr295, which associated with neural precursor cell expressed developmentally downregulated 4e1 recognition and subsequent degradation by ubiquitin proteolysis. Mutation of PGC-1α at Thr295 negated the suppressive effects of shikonin on CAF-stimulated TNBC mitochondrial biogenesis and metastasis in vitro and in vivo. Conclusions Our findings indicate that PGC-1α is a viable target for blocking TNBC metastasis by disrupting mitochondrial biogenesis, and that shikonin merits potential for treatment of TNBC metastasis as an inhibitor of mitochondrial biogenesis through targeting PGC-1α.

Cancer-associated fibroblasts (CAFs) play critical roles in the metastasis and therapeutic response of high-grade serous ovarian cancer (HGSC). Our study intended to select HGSC patients with unfavorable prognoses and therapeutic responses based on CAF-enriched prognostic genes. The bulk RNA and single-cell RNA sequencing (scRNA-seq) data of tumor tissues were collected from the TCGA and GEO databases. The infiltrated levels of immune and stromal cells were estimated by multiple immune deconvolution algorithms and verified through immunohistochemical analysis. The univariate Cox regression analyses were used to identify prognostic genes. Gene Set Enrichment Analysis (GSEA) was conducted to annotate enriched gene sets. The Genomics of Drug Sensitivity in Cancer (GDSC) database was used to explore potential alternative drugs. We found the infiltered levels of CAFs were remarkedly elevated in advanced and metastatic HGSC tissues and identified hundreds of genes specifically enriched in CAFs. Then we selected 6 CAF-enriched prognostic genes based on which HGSC patients were reclassified into 2 subclusters with discrepancy prognoses. Further analysis revealed that the HGSC patients in cluster-2 tended to undergo poor responses to traditional chemotherapy and immunotherapy. Subsequently, we selected 24 novel potential therapeutic drugs for cluster-2 HGSC patients. Moreover, we discovered a positive correlation of infiltrated levels between CAFs and monocytes/macrophages in HGSC tissues. Collectively, our study successfully reclassified HGSC patients into 2 different subgroups that have discrepancy prognoses and responses to current therapeutic methods. [ABSTRACT FROM AUTHOR]

Background: Cancer-associated fibroblasts (CAFs) are the prominent cell type in the tumor microenvironment (TME), and CAF subsets have been identified in various tumors. However, how CAFs spatially coordinate other cell populations within the liver TME to promote cancer progression remains unclear. Methods: We combined multi-region proteomics (6 patients, 24 samples), 10X Genomics Visium spatial transcriptomics (11 patients, 25 samples), and multiplexed imaging (92 patients, 264 samples) technologies to decipher the expression heterogeneity, functional diversity, spatial distribution, colocalization, and interaction of fibroblasts. The newly identified CAF subpopulation was validated by cells isolated from 5 liver cancer patients and in vitro functional assays. Results: We identified a liver CAF subpopulation, marked by the expression of COL1A2, COL4A1, COL4A2, CTGF, and FSTL1, and named F5-CAF. F5-CAF is preferentially located within and around tumor nests and colocalizes with cancer cells with higher stemness in hepatocellular carcinoma (HCC). Multiplexed staining of 92 patients and the bulk transcriptome of 371 patients demonstrated that the abundance of F5-CAFs in HCC was associated with a worse prognosis. Further in vitro experiments showed that F5-CAFs isolated from liver cancer patients can promote the proliferation and stemness of HCC cells. Conclusions: We identified a CAF subpopulation F5-CAF in liver cancer, which is associated with cancer stemness and unfavorable prognosis. Our results provide potential mechanisms by which the CAF subset in the TME promotes the development of liver cancer by supporting the survival of cancer stem cells. [ABSTRACT FROM AUTHOR]

The genetic alterations currently identified in papillary thyroid microcarcinomas (PTMCs) are insufficient for distinguishing tumors with aggressive features. We aimed to identify candidate markers associated with lateral lymph node metastasis (LLNM, N1sb disease) in patients with PTMC using transcriptomic analysis. RNA sequencing was performed on 26 matched tumor and normal thyroid tissue samples (N0, n = 14; N1b, n = 12), followed by functional enrichment analyses of differentially expressed genes (DEGs). EcoTyper was used to explore the distinct tumor microenvironment (TME). We identified 631 DEGs (213 upregulated and 418 downregulated) between N1b and N0 PTMCs. The most significantly upregulated genes in N1b were associated with tumorigenesis, adhesion, migration, and invasion. DEGs were mainly enriched in the pathways of idiopathic pulmonary fibrosis, TME, wound healing, and inhibition of matrix metalloproteases. We predicted the activation of these pathways in N1b PTMCs. N1b PTMCs had a unique TME with abundant fibroblasts and epithelial cells, associated with an increased risk of disease progression. Fibroblast marker genes, including POSTN, MMP11, TNFAIP6, and FN1, and epithelial cell marker genes, including NOX4, MFAP2, TGFVBI, and TNC, were selected. POSTN and FN1, fibroblast cell-specific genes, and NOX4 and TNC, epithelial cell-specific genes, were promising biomarkers for predicting LLNM development and recurrence in patients with PTMC. We delineated the cellular ecotypes within the TME of patients with N1b PTMC and revealed potential markers for predicting LLNM and the prognosis of PTMC. These findings provide valuable insights into the contributions of cancer-associated fibroblasts and epithelial cells to PTMC progression and metastasis. [ABSTRACT FROM AUTHOR]

Cancer-associated fibroblasts (CAFs), as significant constituents of the tumor microenvironment (TME), play a pivotal role in the progression of cancers, including colorectal cancer (CRC). In this comprehensive review, we presented the origins and activation mechanisms of CAFs in CRC, elaborating on how CAFs drive tumor progression through their interactions with CRC cells, immune cells, vascular endothelial cells, and the extracellular matrix within the TME. We systematically outline the intricate web of interactions among CAFs, tumor cells, and other TME components, and based on this complex interplay, we summarize various therapeutic strategies designed to target CAFs in CRC. It is also essential to recognize that CAFs represent a highly heterogeneous group, encompassing various subtypes such as myofibroblastic CAF (myCAF), inflammatory CAF (iCAF), antigen-presenting CAF (apCAF), vessel-associated CAF (vCAF). Herein, we provide a summary of studies investigating the heterogeneity of CAFs in CRC and the characteristic expression patterns of each subtype. While the majority of CAFs contribute to the exacerbation of CRC malignancy, recent findings have revealed specific subtypes that exert inhibitory effects on CRC progression. Nevertheless, the comprehensive landscape of CAF heterogeneity still awaits exploration. We also highlight pivotal unanswered questions that need to be addressed before CAFs can be recognized as feasible targets for cancer treatment. In conclusion, the aim of our review is to elucidate the significance and challenges of advancing in-depth research on CAFs, while outlining the pathway to uncover the complex roles of CAFs in CRC and underscore their significant potential as therapeutic targets. [ABSTRACT FROM AUTHOR]

The functional heterogeneity and ecological niche of prostate cancer stem cells (PCSCs), which are major drivers of prostate cancer development and treatment resistance, have attracted considerable research attention. Cancer-associated fibroblasts (CAFs), which are crucial components of the tumor microenvironment (TME), substantially affect PCSC stemness. Additionally, CAFs promote PCSC growth and survival by releasing signaling molecules and modifying the surrounding environment. Conversely, PCSCs may affect the characteristics and behavior of CAFs by producing various molecules. This crosstalk mechanism is potentially crucial for prostate cancer progression and the development of treatment resistance. Using organoids to model the TME enables an in-depth study of CAF-PCSC interactions, providing a valuable preclinical tool to accurately evaluate potential target genes and design novel treatment strategies for prostate cancer. The objective of this review is to discuss the current research on the multilevel and multitarget regulatory mechanisms underlying CAF-PCSC interactions and crosstalk, aiming to inform therapeutic approaches that address challenges in prostate cancer treatment. [ABSTRACT FROM AUTHOR]

Cancer-associated fibroblasts (CAFs), integral components of the tumor microenvironment, play a pivotal role in tumor proliferation, metastasis, and clinical outcomes. However, its specific roles in Kidney Renal Clear Cell Carcinoma (KIRC) remain poorly understood. Employing the established Seurat single-cell analysis pipeline, we identified 21 CAFs marker genes. Subsequently, a prognostic signature consisting of 6 CAFs marker genes (RGS5, PGF, TPM2, GJA4, SEPT4, and PLXDC1) was developed in a cohort through univariate and LASSO Cox regression analyses. The model's efficacy was then validated in an external cohort, with a remarkable predictive performance in 1-, 3-, and 5-year. Patients in the high-risk group exhibited significantly inferior survival outcomes (p < 0.001), and the risk score was an independent prognostic factor (p < 0.05). Distinct differences in immune cell profiles and drug susceptibility were observed between the two risk groups. In KIRC, the PGF-VEGFR1 signaling pathway displayed a notable increase. PGF expression was significantly elevated in tumor tissues, as demonstrated by quantitative real-time polymerase chain reaction. In vitro, transwell assays and CCK8 revealed that recombinant-PGF could enhance the capability of cell proliferation, migration, and invasion in 769P and 786-O cells. This study firstly developed a novel predictive model based on 6 CAFs genes for KIRC. Additionally, PGF may present a potential therapeutic target to enhance KIRC treatment. [ABSTRACT FROM AUTHOR]

Background: Cancer-associated fibroblasts have become a new target for therapy. Fibroblasts present within malignancies express the fibroblast activation protein (FAP). Inhibitors to FAP (FAPI) are small molecules recently developed as a theranostic agents for imaging and radiotherapy. All currently used FAPI rely on a linker–chelator complex attached to the 'inhibitor'. We describe a new automated method of the direct attachment of the radioisotope to the inhibitor, resulting in a >50% MW reduction with the hope of an improved tumor-to-background ratio and tumor uptake. Methods: [18F]FluroFAPI was developed from a Sn precursor. This allowed for subsequent automated radioflourination. We obtained the biodistribution of [18F]FluroFAPI in rats, performed estimated human radiation dosimetry, and performed a 100× expected single dose toxicology analysis for eventual first-in-human experiments. Results: The synthesis of the Sn precursor for FluorFAPI and the automated synthesis of [18F]FluroFAPI was demonstrated. [18F]FluroFAPI had favorable estimated human radiation dosimetry, and demonstrated no adverse effects when injected at a dose of 100× that planned for [18F]FluroFAPI. Conclusions: With the successful development of an automated synthesis of [18F]FluroFAPI, first-in-human testing can be planned with the hope of an improved tumor-to-background performance compared to other FAPI agents. [ABSTRACT FROM AUTHOR]

Background Objectives Methods Results Conclusion Apoptosis can fuel oncogenesis by the education of surrounding stromal cells. However, the function of cancer‐associated fibroblasts (CAFs), which interacted with apoptotic cancer cells, in oral squamous cell carcinoma (OSCC) progression is still unknown.This study aimed to explore the prognostic value of apoptosis and the biological effects of CAFs, interacted with apoptotic cancer cells, on OSCC.A total of 166 samples from OSCC patients were stained via TUNEL reaction to evaluate the correlation between apoptosis and clinical characteristics. Cell viability and proliferation were assessed through flow cytometry and CCK‐8 assays, respectively. Levels of mRNA and protein were examined through qRT‐PCR, western blot and immunofluorescence.Higher percentage of apoptotic cancer cells in OSCC positively correlated with more Ki67+ cells and predicted poor clinical outcomes. Conditioned medium from CAFs exposed to apoptotic cancer cells significantly facilitated cell proliferation. Co‐culture CAFs with apoptotic cancer cells dampened the phosphorylation of STING/IRF3 signaling, as well as the production of type I interferon, which was required for the inhibition of OSCC cell proliferation.These results demonstrate the interplay between apoptotic cancer cells and CAFs promotes OSCC proliferation via STING signaling, identifying a potential therapy targeted CAFs surrounded with apoptotic cancer cells for OSCC. [ABSTRACT FROM AUTHOR]

Background: Adenocarcinomas show a stepwise progression from atypical adenomatous hyperplasia (AAH) through adenocarcinoma in situ (AIS) to invasive adenocarcinoma (IA). Immunoglobulin superfamily containing leucine-rich repeat (ISLR) is a marker of tumor-restraining cancer-associated fibroblasts (CAFs), which are distinct from conventional, strongly α-smooth muscle actin (αSMA)-positive CAFs. Fibroblast activation protein (FAP) has been focused on as a potential therapeutic and diagnostic target of CAFs. Methods: We investigated the changes in protein expression during adenocarcinoma progression in the pre-existing alveolar septa by assessing ISLR, αSMA, and FAP expression in normal lung, AAH, AIS, and IA. Fourteen AAH, seventeen AIS, and twenty IA lesions were identified and randomly sampled. Immunohistochemical analysis was performed to evaluate cancer-associated changes and FAP expression in the pre-existing alveolar structures. Results: Normal alveolar septa expressed ISLR. The ISLR level in the alveolar septa decreased in AAH and AIS tissues when compared with that in normal lung tissue. The αSMA-positive area gradually increased from the adjacent lung tissue (13.3% ± 15%) to AIS (87.7% ± 14%), through AAH (70.2% ± 21%). Moreover, the FAP-positive area gradually increased from AAH (1.69% ± 1.4%) to IA (11.8% ± 7.1%), through AIS (6.11% ± 5.3%). Protein expression changes are a feature of CAFs in the pre-existing alveolar septa that begin in AAH. These changes gradually progressed from AAH to IA through AIS. Conclusions: FAP-positive fibroblasts may contribute to tumor stroma formation in early-stage lung adenocarcinoma, and this could influence the development of therapeutic strategies targeting FAP-positive CAFs for disrupting extracellular matrix formation. [ABSTRACT FROM AUTHOR]

Despite the dominant roles of cancer-associated fibroblasts (CAFs) have attached much attention in tumorigenesis, the CAFs-derived molecular determinants that regulate renal cell carcinoma (RCC) development remains elusive. Our previous study uncovered an oncogenic SNHG1 in the immune escape of RCC, whereas CAFs-derived exosomes could be a source accounting for increasing SNHG1 in RCC cells, this is still a mystery. The obtained CAFs and normal fibroblast (NFs) from fresh RCC and adjacent tissues were firstly identified using western blot and immunofluorescent staining. The enrichment of SNHG1 was validated by RT-qPCR. CAFs-derived exosomes were isolated from conditioned medium using ultracentrifugation method and ExoQuick-TC system. The internalization of exosomes, transfer of SNHG1, was measured by immunofluorescence. Regulation of conditioned medium or exosomal SNHG1 from CAFs on RCC biological functions was evaluated by CCK-8, EdU incorporation, colony formation, and transwell assays to assess the RCC cell proliferation, migration, and invasion. SNHG1 was significantly upregulated in CAFs isolated from RCC stroma. Exosomes derived from CAFs transferred SNHG1 to RCC cells and resulted in an increased SNHG1 expression in RCC cells. The exosomes excreted by CAFs promoted RCC cell proliferation, migration, and invasion, whereas the promotion effect of CAFs-exosomes on RCC progression was attenuated by SNHG1 knockdown. The present study revealed a new mechanism of exosomal SNHG1 extracted from CAFs enhanced RCC progression and may provide a potential target for the treatment of RCC. [ABSTRACT FROM AUTHOR]

Accumulating evidence suggests that cancer-associated fibroblast (CAF) macroautophagy/autophagy is crucial in tumor development and may be a therapeutic target for pancreatic ductal adenocarcinoma (PDAC). However, the role of CAF autophagy during immune surveillance and cancer immunotherapy is unclear. The present study revealed that the inhibition of CAF autophagy suppresses in vivo tumor development in immune-deficient xenografts. This deletion compromises anti-tumor immunity and anti-tumor efficacy both in vitro and in vivo by upregulating CD274/PDL1 levels in an immune-competent mouse model. A block in CAF autophagy reduced the production of IL6 (interleukin 6), disrupting high desmoplastic TME and decreasing USP14 expression at the transcription level in pancreatic cancer cells. We further identify USP14 as the post-translational factor responsible for downregulating CD274 expression by removing K63 linked-ubiquitination at the K280 residue. Finally, chloroquine diphosphate-loaded mesenchymal stem cell (MSC)-liposomes, by accurately targeting CAFs, inhibited CAF autophagy, improving the efficacy of immunochemotherapy to combat pancreatic cancer. Abbreviation: AIR: adaptive immune resistance; ATRA: all-trans-retinoicacid; CAF: cancer-associated fibroblast; CD274/PDL1: CD274 molecule; CM: conditioned medium; CQ: chloroquine diphosphate; CyTOF: Mass cytometry; FGF2/bFGF: fibroblast growth factor 2; ICB: immune checkpoint blockade; IF: immunofluorescence; IHC: immunohistochemistry; IP: immunoprecipitation; MS: mass spectrometer; MSC: mesenchymal stem cell; PDAC: pancreatic ductal adenocarcinoma; TEM: transmission electron microscopy; TILs: tumor infiltrating lymphocytes; TME: tumor microenvironment; USP14: ubiquitin specific peptidase 14. [ABSTRACT FROM AUTHOR]

Abstract Long non‐coding RNAs (lncRNAs) can crucially regulate activation and transformation of cancer‐associated fibroblasts (CAFs) but have not been systematically investigated at single cell resolution. Here, by utilizing integrated single‐cell sequencing datasets, we screened the aberrantly expressed lncRNAs in CAFs, which are the major component of tumor microenvironment. Our findings revealed a consistent CAF‐specific downregulation of Maternally Expressed Gene 3 (MEG3) expression and increased MEG3+ proportion at the pan‐cancer level, which may be attributed to m6A‐related post‐transcriptional modifications. Through activation trajectory analysis of the major CAF subtypes, it was determined that elevated MEG3 expression in CAFs leads to an increase in PDGFRA expression. This, in turn, promotes CAF activation and transformation into an MEG3+ adipogenic CAF (MACAF) subtype, which is more sensitive to Dasatinib. MACAF‐related cell–cell interactions highlighted that MACAF could enhance the epithelial‐mesenchymal transition process in tumor cells via the TGF‐β pathway, promoting tumor cell migration and possibly contributing to tumor progression and invasiveness. Notably, patients with higher MACAF scores experience unfavorable prognoses and poor response rates to checkpoint inhibitor‐based immunotherapy, suggesting a correlation between MACAF and immunosuppressive microenvironment shaping. Our findings provide novel insights of the MEG3 in CAF activation and highlight the potential value of the MACAF score for therapeutic strategies design involving Dasatinib and immunotherapy.

Abstract Breast cancer, the most frequent female malignancy, is often curable when detected at an early stage. The treatment of metastatic breast cancer is more challenging and may be unresponsive to conventional therapy. Immunotherapy is crucial for treating metastatic breast cancer, but its resistance is a major limitation. The tumor microenvironment (TME) is vital in modulating the immunotherapy response. Various tumor microenvironmental components, such as cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), and myeloid-derived suppressor cells (MDSCs), are involved in TME modulation to cause immunotherapy resistance. This review highlights the role of stromal cells in modulating the breast tumor microenvironment, including the involvement of CAF-TAM interaction, alteration of tumor metabolism leading to immunotherapy failure, and other latest strategies, including high throughput genomic screening, single-cell and spatial omics techniques for identifying tumor immune genes regulating immunotherapy response. This review emphasizes the therapeutic approach to overcome breast cancer immune resistance through CAF reprogramming, modulation of TAM polarization, tumor metabolism, and genomic alterations.

Abstract Background Characterization of shared cancer mechanisms have been proposed to improve therapy strategies and prognosis. Here, we aimed to identify shared cell–cell interactions (CCIs) within the tumor microenvironment across multiple solid cancers and assess their association with cancer mortality. Methods CCIs of each cancer were identified by NicheNet analysis of single-cell RNA sequencing data from breast, colon, liver, lung, and ovarian cancers. These CCIs were used to construct a shared multi-cellular tumor model (shared-MCTM) representing common CCIs across cancers. A gene signature was identified from the shared-MCTM and tested on the mRNA and protein level in two large independent cohorts: The Cancer Genome Atlas (TCGA, 9185 tumor samples and 727 controls across 22 cancers) and UK biobank (UKBB, 10,384 cancer patients and 5063 controls with proteomics data across 17 cancers). Cox proportional hazards models were used to evaluate the association of the signature with 10-year all-cause mortality, including sex-specific analysis. Results A shared-MCTM was derived from five individual cancers. A shared gene signature was extracted from this shared-MCTM and the most prominent regulatory cell type, matrix cancer-associated fibroblast (mCAF). The signature exhibited significant expression changes in multiple cancers compared to controls at both mRNA and protein levels in two independent cohorts. Importantly, it was significantly associated with mortality in cancer patients in both cohorts. The highest hazard ratios were observed for brain cancer in TCGA (HR [95%CI] = 6.90[4.64–10.25]) and ovarian cancer in UKBB (5.53[2.08–8.80]). Sex-specific analysis revealed distinct risks, with a higher mortality risk associated with the protein signature score in males (2.41[1.97–2.96]) compared to females (1.84[1.44–2.37]). Conclusion We identified a gene signature from a comprehensive shared-MCTM representing common CCIs across different cancers and revealed the regulatory role of mCAF in the tumor microenvironment. The pathogenic relevance of the gene signature was supported by differential expression and association with mortality on both mRNA and protein levels in two independent cohorts.

Abstract Heterogeneous cancer-associated fibroblasts (CAFs) play important roles in cancer progression. However, the specific biological functions and regulatory mechanisms involved in endometrial cancer have yet to be elucidated. We aimed to explore the potential mechanisms of heterogeneous CAFs in promoting endometrial cancer progression. The presence of melanoma cell adhesion molecule (MCAM; CD146) positive CAFs was confirmed by tissue multi-immunofluorescence (mIF), and fluorescence activated cell sorting (FACS). The biological functions were determined by wound healing assays, tuber formation assays and cord formation assays. The effects of CD146+CAFs on endometrial cancer cells were studied in vitro and in vivo. The expression level of interleukin 10 (IL-10) was measured by quantitative real time polymerase chain reaction (qRT-PCR), western boltting and enzyme linked immunosorbent assays (ELISAs). In addition, the transcription factor STAT3 was identified by bioinformatics methods and chromatin immunoprecipitation (ChIP). A subtype of CAFs marked with CD146 was found in endometrial cancer and correlated with poor prognosis. CD146+CAFs promoted angiogenesis and vasculogenic mimicry (VM) in vitro. A xenograft tumour model also showed that CD146+CAFs can facilitate tumour progression. The expression of IL-10 was elevated in CD146+CAFs. IL-10 promoted epithelial-endothelial transformation (EET) and further VM formation in endometrial cancer cells via the janus kinase 1/signal transducer and activator of transcription 3 (JAK1/STAT3) signalling pathway. This process could be blocked by the JAK1/STAT3 inhibitor niclosamide. Mechanically, STAT3 can bind to the promoter of cadherin5 (CDH5) to promote its transcription which may be stimulated by IL-10. We concluded that CD146+CAFs could promote angiogenesis and VM formation via the IL-10/JAK1/STAT3 signalling pathway. These findings may lead to the identification of potential targets for antiangiogenic therapeutic strategies for endometrial cancers.

Background: Characterization of shared cancer mechanisms have been proposed to improve therapy strategies and prognosis. Here, we aimed to identify shared cell–cell interactions (CCIs) within the tumor microenvironment across multiple solid cancers and assess their association with cancer mortality. Methods: CCIs of each cancer were identified by NicheNet analysis of single-cell RNA sequencing data from breast, colon, liver, lung, and ovarian cancers. These CCIs were used to construct a shared multi-cellular tumor model (shared-MCTM) representing common CCIs across cancers. A gene signature was identified from the shared-MCTM and tested on the mRNA and protein level in two large independent cohorts: The Cancer Genome Atlas (TCGA, 9185 tumor samples and 727 controls across 22 cancers) and UK biobank (UKBB, 10,384 cancer patients and 5063 controls with proteomics data across 17 cancers). Cox proportional hazards models were used to evaluate the association of the signature with 10-year all-cause mortality, including sex-specific analysis. Results: A shared-MCTM was derived from five individual cancers. A shared gene signature was extracted from this shared-MCTM and the most prominent regulatory cell type, matrix cancer-associated fibroblast (mCAF). The signature exhibited significant expression changes in multiple cancers compared to controls at both mRNA and protein levels in two independent cohorts. Importantly, it was significantly associated with mortality in cancer patients in both cohorts. The highest hazard ratios were observed for brain cancer in TCGA (HR [95%CI] = 6.90[4.64–10.25]) and ovarian cancer in UKBB (5.53[2.08–8.80]). Sex-specific analysis revealed distinct risks, with a higher mortality risk associated with the protein signature score in males (2.41[1.97–2.96]) compared to females (1.84[1.44–2.37]). Conclusion: We identified a gene signature from a comprehensive shared-MCTM representing common CCIs across different cancers and revealed the regulatory role of mCAF in the tumor microenvironment. The pathogenic relevance of the gene signature was supported by differential expression and association with mortality on both mRNA and protein levels in two independent cohorts. [ABSTRACT FROM AUTHOR]

Simple Summary: Invasion of cancer into surrounding tissues is crucial for it to spread to other parts of the body, a process known as metastasis. The characteristics of cancer cells within tumors are significantly influenced by the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are the primary cellular component of the TME and play a pivotal role in cancer progression, including growth, invasion, metastasis, therapy resistance, and immune suppression. Numerous factors mediating interactions between CAFs and cancer cells have been identified, such as growth factors, cytokines, and extracellular vesicles. Recent studies have highlighted the importance of direct contact between CAFs and cancer cells in facilitating cancer invasion and metastasis to distant organs. This review summarizes recent findings on the molecular and cellular mechanisms underlying this direct heterocellular adhesion, providing insights into how CAFs drive cancer invasion and metastasis. Cancer invasion is a requisite for the most malignant progression of cancer, that is, metastasis. The mechanisms of cancer invasion were originally studied using in vitro cell culture systems, in which cancer cells were cultured using artificial extracellular matrices (ECMs). However, conventional culture systems do not precisely recapitulate in vivo cancer invasion because the phenotypes of cancer cells in tumor tissues are strongly affected by the tumor microenvironment (TME). Cancer-associated fibroblasts (CAFs) are the most abundant cell type in the TME and accelerate cancer progression through invasion, metastasis, therapy resistance, and immune suppression. Thus, the reciprocal interactions between CAFs and cancer cells have been extensively studied, leading to the identification of factors that mediate cellular interactions, such as growth factors, cytokines, and extracellular vesicles. In addition, the importance of direct heterocellular adhesion between cancer cells and CAFs in cancer progression has recently been elucidated. In particular, CAFs are directly associated with cancer cells, allowing them to invade the ECM and metastasize to distant organs. In this review, we summarize the recent progress in understanding the molecular and cellular mechanisms of the direct heterocellular interaction in CAF-led cancer invasion and metastasis, with an emphasis on gastric cancer. [ABSTRACT FROM AUTHOR]

Gastric cancer has become the fifth most common cause of cancer-related death worldwide. However, the treatment of gastric cancer remains a challenge. Recently, caveolin-1 has attracted the attention because of its association with cancer-associated fibroblasts that play essential roles in tumor growth. In this study, we established a co-culture model using fibroblasts and gastric cancer cells to mimic tumor microenvironment and investigate the effect of caveolin-1 on the growth of gastric cancer cells. It was found that down-regulation of caveolin-1 in cancer-associated fibroblasts led to cellular autophagy and increased gastric cancer cell growth. This co-culture model promoted the expression of biomarkers of myofibroblasts transformation, including alpha-smooth muscle actin and vimentin. Moreover, quercetin which is a natural polyphenolic flavonoid compound, often used for the treatment of gastric cancer, showed strong inhibitory effect on gastric cancer cell growth in the co-culture; quercetin and unregulated caveolin-1 showed inhibitory activity of myofibroblasts oncogenic transformation both in vitro and in vivo. Quercetin treatment significantly reduced cancer cell migration and invasion, suppressed tumor size and weight. Taken together, our findings have provided new insights on the effect of tumor microenvironment, particularly cancer-associated fibroblast, on tumor cell growth. It has also illustrated the molecular mechanism of quercetin in the treatment of gastric cancer. [ABSTRACT FROM AUTHOR]