Cancer-associated fibroblasts: Origin, function, imaging, and therapeutic targeting

Inhibition of CDH11 Activates cGAS-STING by Stimulating Branched Chain Amino Acid Catabolism and Mitigates Lung Metastasis of Adenoid Cystic Carcinoma

Salivary adenoid cystic carcinoma (SACC) is an intractable malignant tumor originates in the secretory glands and frequently metastasizes to the lungs. Hybrid epithelial-mesenchymal transition (EMT) cells within the tumors are correlated with augmented proliferative capacity and facilitation of lung metastasis. Single-cell RNA sequencing and spatial transcriptomic sequencing are employed to reveal the hybrid EMT subsets within the vascular fibroblast microenvironment. These hybrid EMT cells exhibit a pro-tumorigenic impact in vitro. Notably, cadherin 11 (CDH11), a specific marker for hybrid EMT cells, may exert its regulatory role in cellular function by interfering with branched-chain amino acids (BCAA) metabolism by inhibiting branched-chain ketoacid dehydrogenase to activate the mammalian target of the rapamycin pathway, thus making it a potential therapeutic target for SACC. Furthermore, celecoxib and its derivatives are specific CDH11 inhibitors that regulate BCAA metabolism, increase reactive oxygen species production, and subsequently activate the cyclic GMP-AMP synthase-stimulator of the interferongene pathway (cGAS-STING). They also inhibit lung metastasis in NOD-SCID mice in vivo. Overall, these findings suggest a promising treatment strategy that targets hybrid EMT cells to mitigate lung metastasis in SACC. Celecoxib may serve as a promising clinical intervention for the treatment of lung metastases in patients with SACC.

Tumor exosomal RNPEP promotes lung metastasis of liver cancer via inducing cancer-associated fibroblast activation

Cancer-associated fibroblasts (CAFs) are essential players in the tumor microenvironment (TME) due to their roles in facilitating tumor progression and metastasis. It is worth noting that the high-metastatic hepatocellular carcinoma (HCC) cell-derived exosomes have exhibited the ability to transform normal fibroblasts into CAFs, which further fosters the lung metastasis of low-metastatic HCC cells. Yet, the mechanisms underlying this tumor exosome-induced metastatic niche formation are poorly explored. In this study, the secreted protein arginyl aminopeptidase (RNPEP) was highly expressed in the plasma of patients with HCC. In addition, high-metastatic HCC cells showed augmented RNPEP expression levels in their exosomes. These exosomes induced obvious CAF-like properties in the human fibroblast cell line MRC-5, as evidenced by the increased CAF marker expression, and enhanced migratory ability. More strikingly, the secretions from high-metastatic tumor exosome-educated MRC-5 cells increased tumor stemness and promoted epithelial-mesenchymal transition (EMT) in MHCC-97L cells, a low-metastatic HCC cell line. However, the knockdown of RNPEP in exosomes from high-metastatic HCC cells abated the changes described above. Animal studies in vivo highlighted the pro-tumor and pro-metastatic effects of exosomal RNPEP on MHCC-97L cells by inducing CAF activation. Furthermore, tumor-derived exosomal RNPEP induced the activation of NF-κB signaling in MRC-5 cells, a critical pathway associated with CAF activation. Collectively, these results provide novel insight into tumor-derived exosomal RNPEP for its crosstalk with CAFs during HCC lung metastasis.

Long non-coding RNAs are involved in the crosstalk between cancer-associated fibroblasts and tumor cells

The proliferation of tumors is not merely self-regulated by the cancer cells but is also intrinsically connected to the tumor microenvironment (TME). Within this complex TME, cancer-associated fibroblasts (CAFs) are pivotal in the modulation of tumor onset and progression. Rich signaling interactions exist between CAFs and tumor cells, which are crucial for tumor regulation. Long non-coding RNAs (LncRNAs) emerge from cellular transcription as a class of functionally diverse RNA molecules. Recent studies have revealed that LncRNAs are integral to the crosstalk between CAFs and tumor cells, with the capacity to modify cellular transcriptional activity and secretion profiles, thus facilitating CAFs activation, tumor proliferation, metastasis, drug resistance, and other related functionalities. This comprehensive review revisits the latest research on LncRNA-mediated interactions between CAFs and tumor cells, encapsulates the biological roles of LncRNAs, and delves into the molecular pathways from a broader perspective, aspiring to offer novel perspectives for a deeper comprehension of the etiology of tumors and the enhancement of therapeutic approaches.

Dental pulp stem cells promote malignant transformation of oral epithelial cells through mitochondrial transfer

Oral epithelial dysplasia includes a range of clinical oral mucosal diseases with potentially malignant traits. Dental pulp stem cells (DPSCs) are potential candidates for cell-based therapies targeting various diseases. However, the effect of DPSCs on the progression of oral mucosal precancerous lesions remains unclear. Animal experiments were conducted to assess the effect of human DPSCs (hDPSCs). We measured the proliferation, motility and mitochondrial respiratory function of the human dysplastic oral keratinocyte (DOK) cells cocultured with hDPSCs. Mitochondrial transfer experiments were performed to determine the role mitochondria from hDPSCs in the malignant transformation of DOK cells. hDPSCs injection accelerated carcinogenesis in 4NQO-induced oral epithelial dysplasia in mice. Coculture with hDPSCs increased the proliferation, migration, invasion and mitochondrial respiratory function of DOK cells. Mitochondria from hDPSCs could be transferred to DOK cells, and activated mTOR signaling pathway in DOK cells. Our study demonstrates that hDPSCs activate the mTOR signaling pathway through mitochondrial transfer, promoting the malignant transformation of oral precancerous epithelial lesions.

The roles of periostin derived from cancer-associated fibroblasts in tumor progression and treatment response

Periostin (POSTN), a matricellular protein predominantly secreted by cancer-associated fibroblasts (CAFs), has emerged as a key regulator of cancer progression and therapy response. This review provides an overview of recent findings regarding the diverse roles of periostin in cancer therapy and its potential as a therapeutic target. Studies have elucidated periostin's involvement in tumorigenesis, including tumor growth, metastasis, chemotherapy resistance, and modulation of the tumor microenvironment (TME). CAFs periostin + play a central role in shaping the TME by remodeling the extracellular matrix (ECM) and promoting immune evasion, thus promoting tumor cell survival and dissemination. Elevated periostin expression has been correlated with poor prognosis across multiple cancer types, suggesting its utility as a prognostic biomarker. Periostin has been implicated in mediating resistance to chemotherapy, with CAFs periostin + establishing a pro-tumorigenic niche that confers protection to cancer cells against cytotoxic therapies. Targeting periostin or its downstream effectors presents a promising strategy to overcome therapy resistance and enhance treatment efficacy. While significant progress has been made in understanding the biological functions of periostin in cancer, gaps persist in elucidating its precise mechanisms of action and clinical relevance. Future research should focus on deciphering the signaling pathways and molecular interactions underlying periostin-mediated effects in the TME. Prospective clinical studies are warranted to evaluate periostin as a predictive biomarker and therapeutic target in cancer patients.

Research Progress of Fibroblasts in Human Diseases

Fibroblasts, which originate from embryonic mesenchymal cells, are the predominant cell type seen in loose connective tissue. As the main components of the internal environment that cells depend on for survival, fibroblasts play an essential role in tissue development, wound healing, and the maintenance of tissue homeostasis. Furthermore, fibroblasts are also involved in several pathological processes, such as fibrosis, cancers, and some inflammatory diseases. In this review, we analyze the latest research progress on fibroblasts, summarize the biological characteristics and physiological functions of fibroblasts, and delve into the role of fibroblasts in disease pathogenesis and explore treatment approaches for fibroblast-related diseases.

Decoding tumor-fibrosis interplay: mechanisms, impact on progression, and innovative therapeutic strategies

Malignant tumors are a category of diseases that possess invasive and metastatic capabilities, with global incidence and mortality rates remaining high. In recent years, the pivotal role of fibrosis in tumor progression, drug resistance, and immune evasion has increasingly been acknowledged. Fibrosis enhances the proliferation, migration, and invasion of tumor cells by modifying the composition and structure of the extracellular matrix, thereby offering protection for immune evasion by tumor cells. The activation of cancer-associated fibroblasts (CAFs) plays a significant role in this process, as they further exacerbate the malignant traits of tumors by secreting a variety of cytokines and growth factors. Anti-fibrotic tumor treatment strategies, including the use of anti-fibrotic drugs and inhibition of fibrosis-related signaling pathways such as Transforming Growth Factor-β (TGF-β), have demonstrated potential in delaying tumor progression and improving the effectiveness of chemotherapy, targeted therapy, and immunotherapy. In the future, by developing novel drugs that target the fibrotic microenvironment, new therapeutic options may be available for patients with various refractory tumors.

Cancer-Associated Fibroblasts Expressing Sulfatase 1 Facilitate VEGFA-Dependent Microenvironmental Remodeling to Support Colorectal Cancer

Tumor stroma plays a critical role in fostering tumor progression and metastasis. Cancer-associated fibroblasts (CAF) are a major component of the tumor stroma. Identifying the key molecular determinants for the protumor properties of CAFs could enable the development of more effective treatment strategies. In this study, through analyses of single-cell sequencing data, we identified a population of CAFs expressing high levels of sulfatase 1 (SULF1), which was associated with poor prognosis in patients with colorectal cancer. Colorectal cancer models using mice with conditional SULF1 knockout in fibroblasts revealed the tumor-supportive function of SULF1+ CAFs. Mechanistically, SULF1+ CAFs enhanced the release of VEGFA from heparan sulfate proteoglycan. The increased bioavailability of VEGFA initiated the deposition of extracellular matrix and enhanced angiogenesis. In addition, intestinal microbiota-produced butyrate suppressed SULF1 expression in CAFs through its histone deacetylase (HDAC) inhibitory activity. The insufficient butyrate production in patients with colorectal cancer increased the abundance of SULF1+ CAFs, thereby promoting tumor progression. Importantly, tumor growth inhibition by HDAC was dependent on SULF1 expression in CAFs, and patients with colorectal cancer with more SULF1+ CAFs were more responsive to treatment with the HDAC inhibitor chidamide. Collectively, these findings unveil the critical role of SULF1+ CAFs in colorectal cancer and provide a strategy to stratify patients with colorectal cancer for HDAC inhibitor treatment.  Significance: SULF1+ cancer-associated fibroblasts play a tumor-promoting role in colorectal cancer by stimulating extracellular matrix deposition and angiogenesis and can serve as a biomarker for the therapeutic response to HDAC inhibitors in patients.

Hypoxic Upregulation of IER2 Increases Paracrine GMFG Signaling of Endoplasmic Reticulum Stress-CAF to Promote Chordoma Progression via Targeting ITGB1

Currently, the oncogenic mechanism of endoplasmic reticulum stress-CAF (ERS-CAF) subpopulation in chordoma remains unknown. Here, single-cell RNA sequencing, spatial transcriptomics, GeoMx Digital Spatial Profiler, data-independent acquisition proteomics, bulk RNA-seq, and multiplexed quantitative immunofluorescence are used to unveil the precise molecular mechanism of how ERS-CAF affected chordoma progression. Results show that hypoxic microenvironment reprograms CAFs into ERS-CAF subtype. Mechanistically, this occurrs via hypoxia-mediated transcriptional upregulation of IER2. Overexpression of IER2 in CAFs promotes chordoma progression, which can be impeded by IER2 knockdown or use of ERS inhibitors. IER2 also induces expression of ERS-CAF marker genes and results in production of a pro-tumorigenic paracrine GMFG signaling, which exert its biological function via directly binding to ITGB1 on tumor cells. ITGB1 inhibition attenuates tumor malignant progression, which can be partially reversed by exogenous GMFG intervention. Further analyses reveal a positive correlation between ITGB1high tumor cell counts and SPP1+ macrophage density, as well as the spatial proximity of these two cell types. Clinically, a significant correlation of high IER2/ITGB1 expression with tumor aggressive phenotype and poor patient survival is observed. Collectively, the findings suggest that ERS-CAF regulates SPP1+ macrophage to aggravate chordoma progression via the IER2/GMFG/ITGB1 axis, which may be targeted therapeutically in future.

Therapeutic targets of armored chimeric antigen receptor T cells navigating the tumor microenvironment

Chimeric antigen receptor (CAR) T cell therapy, which targets tumors with high specificity through the recognition of particular antigens, has emerged as one of the most rapidly advancing modalities in immunotherapy, demonstrating substantial success against hematological malignancies. However, previous generations of CAR-T cell therapy encountered numerous challenges in treating solid tumors, such as the lack of suitable targets, high immunosuppression, suboptimal persistence, and insufficient infiltration owing to the complexities of the tumor microenvironment, all of which limited their efficacy. In this review, we focus on the current therapeutic targets of fourth-generation CAR-T cells, also known as armored CAR-T cells, and explore the mechanisms by which these engineered cells navigate the tumor microenvironment by targeting its various components. Enhancing CAR-T cells with these therapeutic targets holds promise for improving their effectiveness against solid tumors, thus achieving substantial clinical value and advancing the field of CAR-T cell therapy. Additionally, we discuss potential strategies to overcome existing challenges and highlight novel targets that could further enhance the efficacy of CAR-T cell therapy in treating solid tumors.

Cancer associated fibroblasts and metabolic reprogramming: unraveling the intricate crosstalk in tumor evolution

Metabolic reprogramming provides tumors with an energy source and biofuel to support their survival in the malignant microenvironment. Extensive research into the intrinsic oncogenic mechanisms of the tumor microenvironment (TME) has established that cancer-associated fibroblast (CAFs) and metabolic reprogramming regulates tumor progression through numerous biological activities, including tumor immunosuppression, chronic inflammation, and ecological niche remodeling. Specifically, immunosuppressive TME formation is promoted and mediators released via CAFs and multiple immune cells that collectively support chronic inflammation, thereby inducing pre-metastatic ecological niche formation, and ultimately driving a vicious cycle of tumor proliferation and metastasis. This review comprehensively explores the process of CAFs and metabolic regulation of the dynamic evolution of tumor-adapted TME, with particular focus on the mechanisms by which CAFs promote the formation of an immunosuppressive microenvironment and support metastasis. Existing findings confirm that multiple components of the TME act cooperatively to accelerate the progression of tumor events. The potential applications and challenges of targeted therapies based on CAFs in the clinical setting are further discussed in the context of advancing research related to CAFs.

Cancer-associated fibroblasts derived exosomal LINC01833 promotes the occurrence of non-small cell lung cancer through miR-335-5p -VAPA axis

Cancer-associated fibroblasts (CAFs) are an important component of the tumor microenvironment (TME) and can induce functional polarization of tumor macrophages. This study aimed to explore the effect of CAFs-derived exosome LINC01833 on the malignant biological behavior of non-small cell lung cancer (NSCLC) cells and its mechanism. Tumor tissues (n = 3) and adjacent noncancerous tissues (n = 3) were collected from patients with NSCLC, and fibroblasts (CAF, NF) were isolated from the two tissues. Expression of LINC01833/miR-335-5p/VAPA in NSCLC clinical tissues and cell lines was detected by RT-qPCR. Exosomes of CAFs and NFs were isolated by ultracentrifugation. Cell proliferation, migration, invasion, and M2 macrophage polarization were detected by MTT, transwell, wound-healing assay, and flow cytometry assay, while western blot was used to verify the expression of M2 macrophage polarization-related proteins. Tumor volume weight and M2 macrophage polarization were detected by tumor xenografts in nude mice. LINC01833 was highly expressed in NSCLC tumor tissues and cells. Knockdown of LINC01833 exosomes could significantly inhibit proliferation, migration, invasion of NSCLC cells, and M2 macrophage polarization of THP-1 cells, while simultaneous knockdown of miR-335-5p on the above basis could reverse the effect of knockdown of LINC01833. In vivo experiments also indicated that knockdown of LINC01833 exosomes suppressed tumor growth and M2 macrophage polarization. CAF-derived LINC01833 exosomes can promote the proliferation, migration and invasion of NSCLC cells and M2 macrophage polarization by inhibiting miR-335-5p and regulating VAPA activity.

Cancer-associated fibroblasts: a versatile mediator in tumor progression, metastasis, and targeted therapy

Tumor microenvironment (TME) has been demonstrated to play a significant role in tumor initiation, progression, and metastasis. Cancer-associated fibroblasts (CAFs) are the major component of TME and exhibit heterogeneous properties in their communication with tumor cells. This heterogeneity of CAFs can be attributed to various origins, including quiescent fibroblasts, mesenchymal stem cells (MSCs), adipocytes, pericytes, endothelial cells, and mesothelial cells. Moreover, single-cell RNA sequencing has identified diverse phenotypes of CAFs, with myofibroblastic CAFs (myCAFs) and inflammatory CAFs (iCAFs) being the most acknowledged, alongside newly discovered subtypes like antigen-presenting CAFs (apCAFs). Due to these heterogeneities, CAFs exert multiple functions in tumorigenesis, cancer stemness, angiogenesis, immunosuppression, metabolism, and metastasis. As a result, targeted therapies aimed at the TME, particularly focusing on CAFs, are rapidly developing, fueling the promising future of advanced tumor-targeted therapy.

The neoantigens derived from transposable elements - A hidden treasure for cancer immunotherapy

Neoantigen-based therapy is a promising approach that selectively activates the immune system of the host to recognize and eradicate cancer cells. Preliminary clinical trials have validated the feasibility, safety, and immunogenicity of personalized neoantigen-directed vaccines, enhancing their effectiveness and broad applicability in immunotherapy. While many ongoing oncological trials concentrate on neoantigens derived from mutations, these targets do not consistently provoke an immune response in all patients harboring the mutations. Additionally, tumors like ovarian cancer, which have a low tumor mutational burden (TMB), may be less amenable to mutation-based neoantigen therapies. Recent advancements in next-generation sequencing and bioinformatics have uncovered a rich source of neoantigens from non-canonical RNAs associated with transposable elements (TEs). Considering the substantial presence of TEs in the human genome and the proven immunogenicity of TE-derived neoantigens in various tumor types, this review investigates the latest findings on TE-derived neoantigens, examining their clinical implications, challenges, and unique advantages in enhancing tumor immunotherapy.

Efficacy and Safety Evaluation of 177Lu-FAP-2286 in the Treatment of Advanced Lung Cancer

PURPOSE

The aim of this study was to evaluate the efficacy and safety of peptide-targeted radionuclide therapy (PTRT) with 177Lu-FAP-2286 in advanced lung cancer.

PATIENTS AND METHODS

This single-center prospective study included 9 patients diagnosed with advanced lung cancer. These patients met the inclusion criteria and received PTRT with 177Lu-FAP-2286. Short-term efficacy was assessed using RECIST 1.1 and PERCIST 1.0 criteria. Long-term efficacy was evaluated through overall survival, progression-free survival (PFS), overall response rate, EORTC QLQ-C30 v3.0, Eastern Cooperative Oncology Group, and Karnofsky Performance Status. Toxicity response was assessed using CTCAE v5.0.

RESULTS

The results based on RECIST 1.1 and PERCIST 1.0 criteria were comparable, with 44% of patients showing a partial metabolic response, 33.3% with stable metabolic disease, and 22.22% with progressive metabolic disease. The highest metabolic response after treatment reached 66.89%, and the overall response rate could reach 77.78%. In the long-term efficacy assessment, the median overall survival and PFS were 10 months and 6 months, respectively. The 2 patients with the lowest PFS (3 months) started PTRT relatively late. EORTC QLQ-C30 v3.0, Eastern Cooperative Oncology Group, and Karnofsky Performance Status scores showed that the overall health status, symptom response, and quality of life of patients improved after 177Lu-FAP-2286 treatment. The most noticeable improvements in clinical symptoms were dyspnea and cancer-related pain. No grade III/IV toxicity events were observed during follow-up period, and fibrinogen decreased significantly after treatment.

CONCLUSIONS

177Lu-FAP-2286 has the potential to be a viable PTRT option for patients with advanced lung cancer.

Immunotherapy and the ovarian cancer microenvironment: Exploring potential strategies for enhanced treatment efficacy

Despite progress in cancer immunotherapy, ovarian cancer (OC) prognosis continues to be disappointing. Recent studies have shed light on how not just tumour cells, but also the complex tumour microenvironment, contribute to this unfavourable outcome of OC immunotherapy. The complexities of the immune microenvironment categorize OC as a 'cold tumour'. Nonetheless, understanding the precise mechanisms through which the microenvironment influences the effectiveness of OC immunotherapy remains an ongoing scientific endeavour. This review primarily aims to dissect the inherent characteristics and behaviours of diverse cells within the immune microenvironment, along with an exploration into its reprogramming and metabolic changes. It is expected that these insights will elucidate the operational dynamics of the immune microenvironment in OC and lay a theoretical groundwork for improving the efficacy of immunotherapy in OC management.

Emerging role of immunogenic cell death in cancer immunotherapy: Advancing next-generation CAR-T cell immunotherapy by combination

Immunogenic cell death (ICD) is a stress-driven form of regulated cell death (RCD) in which dying tumor cells' specific signaling pathways are activated to release damage-associated molecular patterns (DAMPs), leading to the robust anti-tumor immune response as well as a reversal of the tumor immune microenvironment from "cold" to "hot". Chimeric antigen receptor (CAR)-T cell therapy, as a landmark in anti-tumor immunotherapy, plays a formidable role in hematologic malignancies but falls short in solid tumors. The Gordian knot of CAR-T cells for solid tumors includes but is not limited to, tumor antigen heterogeneity or absence, physical and immune barriers of tumors. The combination of ICD induction therapy and CAR-T cell immunotherapy is expected to promote the intensive use of CAR-T cell in solid tumors. In this review, we summarize the characteristics of ICD, stress-responsive mechanism, and the synergistic effect of various ICD-based therapies with CAR-T cells to effectively improve anti-tumor capacity.

Applications of nanotechnology in remodeling the tumour microenvironment for glioblastoma treatment

With the increasing research and deepening understanding of the glioblastoma (GBM) tumour microenvironment (TME), novel and more effective therapeutic strategies have been proposed. The GBM TME involves intricate interactions between tumour and non-tumour cells, promoting tumour progression. Key therapeutic goals for GBM treatment include improving the immunosuppressive microenvironment, enhancing the cytotoxicity of immune cells against tumours, and inhibiting tumour growth and proliferation. Consequently, remodeling the GBM TME using nanotechnology has emerged as a promising approach. Nanoparticle-based drug delivery enables targeted delivery, thereby improving treatment specificity, facilitating combination therapies, and optimizing drug metabolism. This review provides an overview of the GBM TME and discusses the methods of remodeling the GBM TME using nanotechnology. Specifically, it explores the application of nanotechnology in ameliorating immune cell immunosuppression, inducing immunogenic cell death, stimulating, and recruiting immune cells, regulating tumour metabolism, and modulating the crosstalk between tumours and other cells.

Dendritic nanomedicine enhances chemo-immunotherapy by disturbing metabolism of cancer-associated fibroblasts for deep penetration and activating function of immune cells

Inefficient drug penetration hurdled by the stroma in the tumor tissue leads to a diminished therapeutic effect for drugs and a reduced infiltration level of immune cells. Herein, we constructed a PEGylated dendritic epirubicin (Epi) prodrug (Epi-P4D) to regulate the metabolism of cancer-associated fibroblasts (CAFs), thus enhancing Epi penetration into both multicellular tumor spheroids (MTSs) and tumor tissues in mouse colon cancer (CT26), mouse breast cancer (4T1) and human breast cancer (MDA-MB-231) models. Enhanced cytotoxicity against CT26 MTSs and remarkable antitumor efficacy of Epi-P4D were ascribed to reduced fibronectin, α-SMA, and collagen secretion. Besides, thinning of the tumor tissue stroma and efficient eradication of tumor cells promoted the immunogenic cell death effect for dendritic cell (DC) maturation and subsequent immune activation, including elevating the CD4+ T cell population, reducing CD4+ and CD8+ T cell hyperactivation and exhaustion, and amplifying the natural killer (NK) cell proportion and effectively activating them. As a result, this dendritic nanomedicine thinned the stroma of tumor tissues to enhance drug penetration and facilitate immune cell infiltration for elevated antitumor efficacy.

Membrane Fusion Liposomes Deliver Antifibrotic and Chemotherapeutic Drugs Sequentially to Enhance Tumor Treatment Efficacy by Reshaping Tumor Microenvironment

The intricate tumor microenvironment in triple-negative breast cancer (TNBC) hampers chemotherapy and immunotherapy efficacy due to dense extracellular matrix (ECM) by tumor-associated fibroblasts (TAFs). Nanoparticle-based therapies, especially "all-in-one" nanoparticles, have shown great potential in combined drug delivery strategies to reshape the tumor microenvironment and enhance therapeutic efficiency. However, these "all-in-one" nanoparticles suffer from limitations in targeting different target cells, uncontrollable dosing ratio, and disregarding the impact of delivery schedules. This study prepared cell membrane fusion liposomes (TAFsomes and CCMsomes) to load FDA-approved antifibrotic drug pirfenidone (PFD/TAFsomes) and antitumor drug doxorubicin (DOX/CCMsomes). These liposomes can specifically target TAFs cells and tumor cells, and combined administration can effectively inhibit TAFs activity, reshape the tumor microenvironment (TME), and significantly enhance the tumor chemotherapy efficacy. Combined drug delivery defeats "all-in-one" liposomes (DOX/PFD/Liposomes, DOX/PFD/TAFsomes, and DOX/PFD/CCMsomes) by flexibly adjusting the drug delivery ratio. Moreover, an asynchronous delivery strategy that optimizes the administration schedule not only further improves the therapeutic effect, but also amplifies the effectiveness of α-PD-L1 immunotherapy by modulating the tumor immune microenvironment. This delivery strategy provides a personalized treatment approach with clinical translation potential, providing new ideas for enhancing the therapeutic effect against solid tumors such as TNBC.

Far-Red Aggregation-Induced Emission Hydrogel-Reinforced Tissue Clearing for 3D Vasculature Imaging of Whole Lung and Whole Tumor

Understanding the vascular formation and distribution in metastatic lung tumors is a significant challenge due to autofluorescence, antibody/dye diffusion in dense tumor, and fluorophore stability when exposed to solvent-based clearing agents. Here, an approach is presented that redefines 3D vasculature imaging within metastatic tumor, peritumoral lung tissue, and normal lung. Specifically, a far-red aggregation-induced emission nanoparticle with surface amino groups (termed as TSCN nanoparticle, TSCNNP) is designed for in situ formation of hydrogel (TSCNNP@Gel) inside vasculatures to provide structural support and enhance the fluorescence in solvent-based tissue clearing method. Using this TSCNNP@Gel-reinforced tissue clearing imaging approach, the critical challenges are successfully overcome and comprehensive visualization of the whole pulmonary vasculature up to 2 µm resolution is enabled, including its detailed examination in metastatic tumors. Importantly, features of tumor-associated vasculature in 3D panoramic views are unveiled, providing the potential to determine tumor stages, predict tumor progression, and facilitate the histopathological diagnosis of various tumor types.

The role of cancer-associated fibroblasts in the invasion and metastasis of colorectal cancer

Colorectal cancer (CRC) is the third most common cancer and has ranked the third leading cause in cancerassociated death globally. Metastasis is the leading cause of death in colorectal cancer patients. The role of tumor microenvironment (TME) in colorectal cancer metastasis has received increasing attention. As the most abundant cell type in the TME of solid tumors, cancer-associated fibroblasts (CAFs) have been demonstrated to have multiple functions in advancing tumor growth and metastasis. They can remodel the extracellular matrix (ECM) architecture, promote epithelial-mesenchymal transition (EMT), and interact with cancer cells or other stromal cells by secreting growth factors, cytokines, chemokines, and exosomes, facilitating tumor cell invasion into TME and contributing to distant metastasis. This article aims to analyze the sources and heterogeneity of CAFs in CRC, as well as their role in invasion and metastasis, in order to provide new insights into the metastasis mechanism of CRC and its clinical applications.

Advances in targeting cancer-associated fibroblasts through single-cell spatial transcriptomic sequencing

Cancer-associated fibroblasts (CAFs) are the major components of the tumor microenvironment and are related to tumor proliferation, metastasis, relapse, and drug resistance. With the development of sequencing technologies, single-cell RNA sequencing has become a popular method for identifying CAFs in the tumor microenvironment. Whereas the drawbacks of CAFs, such as the lack of a spatial landscape, still exist, recent research has utilized spatial transcriptomics combined with single-cell RNA sequencing to address this issue. These multiomics analyses can resolve the single-cell resolution problem in spatial transcriptomics. In this review, we summarized the recent literature regarding the targeting of CAFs to address drug resistance, angiogenesis, metabolic reprogramming and metastasis in tumor tissue.

Hydrogen Therapy Reverses Cancer-Associated Fibroblasts Phenotypes and Remodels Stromal Microenvironment to Stimulate Systematic Anti-Tumor Immunity

Tumor microenvironment (TME) plays an important role in the tumor progression. Among TME components, cancer-associated fibroblasts (CAFs) show multiple tumor-promoting effects and can induce tumor immune evasion and drug-resistance. Regulating CAFs can be a potential strategy to augment systemic anti-tumor immunity. Here, the study observes that hydrogen treatment can alleviate intracellular reactive oxygen species of CAFs and reshape CAFs' tumor-promoting and immune-suppressive phenotypes. Accordingly, a controllable and TME-responsive hydrogen therapy based on a CaCO3 nanoparticles-coated magnesium system (Mg-CaCO3) is developed. The hydrogen therapy by Mg-CaCO3 can not only directly kill tumor cells, but also inhibit pro-tumor and immune suppressive factors in CAFs, and thus augment immune activities of CD4+ T cells. As implanted in situ, Mg-CaCO3 can significantly suppress tumor growth, turn the "cold" primary tumor into "hot", and stimulate systematic anti-tumor immunity, which is confirmed by the bilateral tumor transplantation models of "cold tumor" (4T1 cells) and "hot tumor" (MC38 cells). This hydrogen therapy system reverses immune suppressive phenotypes of CAFs, thus providing a systematic anti-tumor immune stimulating strategy by remodeling tumor stromal microenvironment.

Glucocorticoids in lung cancer: Navigating the balance between immunosuppression and therapeutic efficacy

Glucocorticoids (GCs), a class of hormones secreted by the adrenal glands, are released into the bloodstream to maintain homeostasis and modulate responses to various stressors. These hormones function by binding to the widely expressed GC receptor (GR), thereby regulating a wide range of pathophysiological processes, especially in metabolism and immunity. The role of GCs in the tumor immune microenvironment (TIME) of lung cancer (LC) has been a focal point of research. As immunosuppressive agents, GCs exert a crucial impact on the occurrence, progression, and treatment of LC. In the TIME of LC, GCs act as a constantly swinging pendulum, simultaneously offering tumor-suppressive properties while diminishing the efficacy of immune-based therapies. The present study reviews the role and mechanisms of GCs in the TIME of LC.

Comprehensive analysis and experimental verification reveal the molecular characteristics of EGLN3 in pan-cancer and its relationship with the proliferation and apoptosis of lung cancer

Background

Egl-9 family hypoxia-inducible factor 3 (EGLN3) is involved in the regulation of tumor microenvironment and tumor progression. However, its biological function and clinical significance in various cancers remain unclear.

Methods

RNA-seq, immunofluorescence, and single-cell sequencing were used to investigate the expression landscape of EGLN3 in pan-cancer. The TISCH2 and CancerSEA databases were used for single-cell function analysis of EGLN3 in tumors. TIMER2.0 database was used to explain the relationship between EGLN3 expression and immune cell infiltration. In addition, the LinkedOmics database was used to perform KEGG enrichment analysis of EGLN3 in pan-cancer. siRNA was used to silence gene expression. CCK8, transwell migration assay, flow cytometry analysis, RT-PCR, and western blotting were used to explore biological function of EGLN3.

Results

The results showed that EGLN3 was highly expressed in a variety of tumors, and was mainly localized to the cytosol. EGLN3 expression is associated with immunoinfiltration of a variety of immune cells, including macrophages in the tumor immune microenvironment and tumor-associated fibroblasts. Functional experiments revealed that EGLN3 knockdown could inhibit cell proliferation, migration, and promote cell apoptosis. In addition, we found that Bax expression was up-regulated and Bcl-2 expression was down-regulated in the si-EGLN3 group. Taken together, as a potential oncogene, EGLN3 is involved in the regulation of tumor malignant process, especially tumor cell apoptosis.

Conclusion

We comprehensively investigated the expression pattern, single-cell function, immune infiltration level and regulated signaling pathway of EGLN3 in pan-cancer. We found that EGLN3 is an important hypoxia and immune-related gene that may serve as a potential target for tumor immunotherapy.

Fibronectin-Targeting Dual-Modal MR/NIRF Imaging Contrast Agents for Diagnosis of Gastric Cancer and Peritoneal Metastasis

The prevalence and fatality rates of gastric cancer (GC) remain elevated, with advanced stages presenting a grim prognosis. Noninvasive diagnosis of GC cancer often proves challenging until the disease has progressed to an advanced stage or metastasized. Initially, the level of fibronectin (FN) in cancer-associated fibroblasts (CAFs) of GC was at least 3.7 times higher than that in normal fibroblasts. Herein, two FN-targeting magnetic resonance/near-infrared fluorescence (MR/NIRF) imaging contrast agents were developed to detect GC and peritoneal metastasis noninvasively. The probes CREKA-Cy7-(Gd-DOTA) and CREKA-Cy7-(Gd-DOTA)3 demonstrated significant FN-targeting capability (with dissociation constants of 1.0 and 2.1 mM) and effective MR imaging performance (with proton relaxivity values of 9.66 and 27.44 mM-1 s-1 at 9.4 T, 37 °C). In vivo imaging revealed a high signal-to-noise ratio and successful visualization of GC metastasis using NIRF imaging as well as successful tumor detection in MR imaging. Therefore, this study highlights the potential of FN-targeting probes for GC diagnosis and aids in the advancement of new diagnostic strategies for the clinical detection of GC.

Molecular mechanisms of secretory autophagy and its potential role in diseases

Autophagy is a cellular degradation system that recycles or degrades damaged organelles, viral particles, and aggregated proteins through the lysosomal pathway. Autophagy plays an indispensable role in cellular homeostasis and communication processes. An interesting aspect is that autophagy also mediates the secretion of cellular contents, a process known as secretory autophagy. Secretory autophagy differs from macroautophagy, which sequesters recruited proteins, organelles, or viral particles into autophagosomes and degrades these sequesters in lysosomes, while the secretory autophagy pathway participates in the extracellular export of cellular contents sequestered by autophagosomes through autophagy and endosomal modulators. Recent evidence reveals that secretory autophagy is pivotal in the occurrence and progression of diseases. In this review, we summarize the molecular mechanisms of secretory autophagy. Furthermore, we review the impact of secretory autophagy on diseases, including cancer, viral infectious diseases, neurodegenerative diseases, and cardiovascular diseases. Considering the pleiotropic actions of secretory autophagy on diseases, studying the mechanism of secretory autophagy may help to understand the relevant pathophysiological processes.

Biophysical and biochemical aspects of immune cell-tumor microenvironment interactions

The tumor microenvironment (TME), composed of and influenced by a heterogeneous set of cancer cells and an extracellular matrix, plays a crucial role in cancer progression. The biophysical aspects of the TME (namely, its architecture and mechanics) regulate interactions and spatial distributions of cancer cells and immune cells. In this review, we discuss the factors of the TME-notably, the extracellular matrix, as well as tumor and stromal cells-that contribute to a pro-tumor, immunosuppressive response. We then discuss the ways in which cells of the innate and adaptive immune systems respond to tumors from both biochemical and biophysical perspectives, with increased focus on CD8+ and CD4+ T cells. Building upon this information, we turn to immune-based antitumor interventions-specifically, recent biophysical breakthroughs aimed at improving CAR-T cell therapy.

Dendritic Polymer-Based Nanomedicines Remodel the Tumor Stroma: Improve Drug Penetration and Enhance Antitumor Immune Response

The dense extracellular matrix (ECM) in solid tumors, contributed by cancer-associated fibroblasts (CAFs), hinders penetration of drugs and diminishes their therapeutic outcomes. A sequential treatment strategy of remodeling the ECM via a CAF modifier (dasatinib, DAS) is proposed to promote penetration of an immunogenic cell death (ICD) inducer (epirubicin, Epi) via apoptotic vesicles, ultimately enhancing the treatment efficacy against breast cancer. Dendritic poly(oligo(ethylene glycol) methyl ether methacrylate) (POEGMA)-based nanomedicines (poly[OEGMA-Dendron(G2)-Gly-Phe-Leu-Gly-DAS] (P-DAS) and poly[OEGMA-Dendron(G2)-hydrazone-Epi] (P-Epi)) are developed for sequential delivery of DAS and Epi, respectively. P-DAS reprograms CAFs to reduce collagen by downregulating collagen anabolism and energy metabolism, thereby reducing the ECM deposition. The regulated ECM can enhance tumor penetration of P-Epi to strengthen its ICD effect, leading to an amplified antitumor immune response. In breast cancer-bearing mice, this approach alleviates the ECM barrier, resulting in reduced tumor burden and increased cytotoxic T lymphocyte infiltration, and more encouragingly, synergizes effectively with anti-programmed cell death 1 (PD-1) therapy, significantly inhibiting tumor growth and preventing lung metastasis. Furthermore, systemic toxicity is barely detectable after sequential treatment with P-DAS and P-Epi. This approach opens a new avenue for treating desmoplastic tumors by metabolically targeting CAFs to overcome the ECM barrier.

Anlotinib may enhance the efficacy of anti-PD1 therapy by inhibiting the AKT pathway and promoting the apoptosis of CAFs in lung adenocarcinoma

Although PD-1 inhibitors have revolutionized the treatment paradigm of non-small cell lung cancer (NSCLC), their efficacy in treating NSCLC has remained unsatisfactory. Targeting cancer-associated fibroblasts (CAFs) is a potential approach for improving the immunotherapy response. Multitarget antiangiogenic tyrosine kinase receptor inhibitors (TKIs) can enhance the efficacy of PD-1 inhibitors in NSCLC patients. However, the effects and mechanisms of antiangiogenic TKIs on CAFs have not been elucidated. In this study, we first compared anlotinib with other antiangiogenic TKIs and confirmed the superior efficacy of anlotinib. Furthermore, we established NSCLC-associated CAF models and found that anlotinib impaired CAF viability and migration capacity and contributed to CAF apoptosis and cell cycle arrest in the G2/M phase. Moreover, anlotinib treatment attenuated the capacity of CAFs to recruit lung cancer cells and macrophages. Experiments in animal models suggested that anlotinib could enhance the efficacy of anti-PD1 therapy in NSCLC and affect CAF proliferation and apoptosis. Anlotinib increased the abundance of tumor-infiltrating CD8 + T cells, and PD-1 inhibitor-induced cytotoxicity to tumor cells was achieved through the transformation of the tumor microenvironment (TME) caused by anlotinib, which may partly explain the synergistic antitumor effect of anlotinib and PD-1 inhibitors. Mechanistically, anlotinib affects CAF apoptosis and cell viability at least in part by inhibiting the AKT pathway. In conclusion, our study suggested that anlotinib could regulate the TME, inhibit the AKT pathway and promote CAF apoptosis, providing new insights into the antitumor effect of anlotinib and improving the efficacy of immunotherapy.

Rational Design and Pharmacomodulation of 18F-Labeled Biotin/FAPI-Conjugated Heterodimers

Due to the complex heterogeneity in different cancer types, the heterodimeric strategy has been intensively practiced to improve the effectiveness of tumor diagnostics. In this study, we developed a series of novel 18F-labeled biotin/FAPI-conjugated heterobivalent radioligands ([18F]AlF-NSFB, [18F]AlF-NSFBP2, and [18F]AlF-NSFBP4), synergistically targeting both fibroblast activation protein (FAP) and biotin receptor (BR), to enhance specific tumor uptake and retention. The in vitro and in vivo biological properties of these dual-targeting tracers were evaluated, with a particular focus on positron emission tomography imaging in A549 and HT1080-FAP tumor-bearing mice. Notably, in comparison to the corresponding FAP-targeted monomer [18F]AlF-NSF, biotin/FAPI-conjugated heterodimers exhibited a high uptake in tumor and prolong retention. In conclusion, as a proof-of-concept study, the findings validated the superiority of biotin/FAPI-conjugated heterodimers and the positive influence of biotin and linker on pharmacokinetics of radioligands. Within them, the bispecific [18F]AlF-NSFBP4 holds significant promise as a candidate for further clinical translational studies.

Prognostic and therapeutic potential of senescent stromal fibroblasts in prostate cancer

The stromal component of the tumour microenvironment in primary and metastatic prostate cancer can influence and promote disease progression. Within the prostatic stroma, fibroblasts are one of the most prevalent cell types associated with precancerous and cancerous lesions; they have a vital role in the structural composition, organization and integrity of the extracellular matrix. Fibroblasts within the tumour microenvironment can undergo cellular senescence, which is a stable arrest of cell growth and a phenomenon that is emerging as a recognized hallmark of cancer. Supporting the idea that cellular senescence has a pro-tumorigenic role, a subset of senescent cells exhibits a senescence-associated secretory phenotype (SASP), which, along with increased inflammation, can promote prostate cancer cell growth and survival. These cellular characteristics make targeting senescent cells and/or modulating SASP attractive as a potential preventive or therapeutic option for prostate cancer.

CD63+ cancer-associated fibroblasts confer CDK4/6 inhibitor resistance to breast cancer cells by exosomal miR-20

Cyclin-dependent kinase 4 (CDK4) and CDK6 inhibitors (CDK4/6i) have rapidly received Food and Drug Administration (FDA) approval as a new type of therapy for patients with advanced hormone receptor-positive breast cancer. However, with the widespread application of CDK4/6i, drug resistance has become a new challenge for clinical practice and has greatly limited the treatment effect. Here, the whole microenvironment landscape of ER+ breast cancer tumors was revealed through single-cell RNA sequencing, and a specific subset of cancer-associated fibroblasts (CD63+ CAFs) was identified as highly enriched in CDK4/6i resistant tumor tissues. Then, we found that CD63+ CAFs can distinctly promote resistance to CDK4/6i in breast cancer cells and tumor xenografts. In addition, it was discovered that miR-20 is markedly enriched in the CD63+ CAFs-derived exosomes, which are used to communicate with ER+ breast cancer cells, leading to CDK4/6i resistance. Furthermore, exosomal miR-20 could directly target the RB1 mRNA 3'UTR and negatively regulate RB1 expression to decrease CDK4/6i sensitivity in breast cancer cells. Most importantly, we designed and synthesized cRGD-miR-20 sponge nanoparticles and found that they can enhance the therapeutic effect of CDK4/6i in breast cancer. In summary, our findings reveal that CD63+ CAFs can promote CDK4/6i resistance via exosomal miR-20, which induces the downregulation of RB1 in breast cancer cells, and suggest that CD63+ CAFs may be a novel therapeutic target to enhance CDK4/6i sensitivity.

Crosstalk between cancer-associated fibroblasts and regulated cell death in tumors: insights into apoptosis, autophagy, ferroptosis, and pyroptosis

Cancer-associated fibroblasts (CAFs), the main stromal component of the tumor microenvironment (TME), play multifaceted roles in cancer progression through paracrine signaling, exosome transfer, and cell interactions. Attractively, recent evidence indicates that CAFs can modulate various forms of regulated cell death (RCD) in adjacent tumor cells, thus involving cancer proliferation, therapy resistance, and immune exclusion. Here, we present a brief introduction to CAFs and basic knowledge of RCD, including apoptosis, autophagy, ferroptosis, and pyroptosis. In addition, we further summarize the different types of RCD in tumors that are mediated by CAFs, as well as the effects of these modes of RCD on CAFs. This review will deepen our understanding of the interactions between CAFs and RCD and might offer novel therapeutic avenues for future cancer treatments.

An exosomal strategy for targeting cancer-associated fibroblasts mediated tumors desmoplastic microenvironments

Tumors desmoplastic microenvironments are characterized by abundant stromal cells and extracellular matrix (ECM) deposition. Cancer-associated fibroblasts (CAFs), as the most abundant of all stromal cells, play significant role in mediating microenvironments, which not only remodel ECM to establish unique pathological barriers to hinder drug delivery in desmoplastic tumors, but also talk with immune cells and cancer cells to promote immunosuppression and cancer stem cells-mediated drug resistance. Thus, CAFs mediated desmoplastic microenvironments will be emerging as promising strategy to treat desmoplastic tumors. However, due to the complexity of microenvironments and the heterogeneity of CAFs in such tumors, an effective deliver system should be fully considered when designing the strategy of targeting CAFs mediated microenvironments. Engineered exosomes own powerful intercellular communication, cargoes delivery, penetration and targeted property of desired sites, which endow them with powerful theranostic potential in desmoplastic tumors. Here, we illustrate the significance of CAFs in tumors desmoplastic microenvironments and the theranostic potential of engineered exosomes targeting CAFs mediated desmoplastic microenvironments in next generation personalized nano-drugs development.

The hidden messengers: cancer associated fibroblasts-derived exosomal miRNAs as key regulators of cancer malignancy

Cancer-associated fibroblasts (CAFs), a class of stromal cells in the tumor microenvironment (TME), play a key role in controlling cancer cell invasion and metastasis, immune evasion, angiogenesis, and resistance to chemotherapy. CAFs mediate their activities by secreting soluble chemicals, releasing exosomes, and altering the extracellular matrix (ECM). Exosomes contain various biomolecules, such as nucleic acids, lipids, and proteins. microRNA (miRNA), a 22-26 nucleotide non-coding RNA, can regulate the cellular transcription processes. Studies have shown that miRNA-loaded exosomes secreted by CAFs engage in various regulatory communication networks with other TME constituents. This study focused on the roles of CAF-derived exosomal miRNAs in generating cancer malignant characteristics, including immune modulation, tumor growth, migration and invasion, epithelial-mesenchymal transition (EMT), and treatment resistance. This study thoroughly examines miRNA's dual regulatory roles in promoting and suppressing cancer. Thus, changes in the CAF-derived exosomal miRNAs can be used as biomarkers for the diagnosis and prognosis of patients, and their specificity can be used to develop newer therapies. This review also discusses the pressing problems that require immediate attention, aiming to inspire researchers to explore more novel avenues in this field.

Tumor Microenvironment Modulation by Cancer-Derived Extracellular Vesicles

The tumor microenvironment (TME) plays an important role in the process of tumorigenesis, regulating the growth, metabolism, proliferation, and invasion of cancer cells, as well as contributing to tumor resistance to the conventional chemoradiotherapies. Several types of cells with relatively stable phenotypes have been identified within the TME, including cancer-associated fibroblasts (CAFs), tumor-associated macrophages (TAMs), neutrophils, and natural killer (NK) cells, which have been shown to modulate cancer cell proliferation, metastasis, and interaction with the immune system, thus promoting tumor heterogeneity. Growing evidence suggests that tumor-cell-derived extracellular vesicles (EVs), via the transfer of various molecules (e.g., RNA, proteins, peptides, and lipids), play a pivotal role in the transformation of normal cells in the TME into their tumor-associated protumorigenic counterparts. This review article focuses on the functions of EVs in the modulation of the TME with a view to how exosomes contribute to the transformation of normal cells, as well as their importance for cancer diagnosis and therapy.

The Application of Nanoparticles Targeting Cancer-Associated Fibroblasts

Cancer-associated fibroblasts (CAF) are the most abundant stromal cells in the tumor microenvironment (TME), especially in solid tumors. It has been confirmed that it can not only interact with tumor cells to promote cancer progression and metastasis, but also affect the infiltration and function of immune cells to induce chemotherapy and immunotherapy resistance. So, targeting CAF has been considered an important method in cancer treatment. The rapid development of nanotechnology provides a good perspective to improve the efficiency of targeting CAF. At present, more and more researches have focused on the application of nanoparticles (NPs) in targeting CAF. These studies explored the effects of different types of NPs on CAF and the multifunctional nanomedicines that can eliminate CAF are able to enhance the EPR effect which facilitate the anti-tumor effect of themselves. There also exist amounts of studies focusing on using NPs to inhibit the activation and function of CAF to improve the therapeutic efficacy. The application of NPs targeting CAF needs to be based on an understanding of CAF biology. Therefore, in this review, we first summarized the latest progress of CAF biology, then discussed the types of CAF-targeting NPs and the main strategies in the current. The aim is to elucidate the application of NPs in targeting CAF and provide new insights for engineering nanomedicine to enhance immune response in cancer treatment.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSION

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

Modulator of TMB-associated immune infiltration (MOTIF) predicts immunotherapy response and guides combination therapy

Patients with high tumor mutational burden (TMB) levels do not consistently respond to immune checkpoint inhibitors (ICIs), possibly because a high TMB level does not necessarily result in adequate infiltration of CD8+ T cells. Using bulk ribonucleic acid sequencing (RNA-seq) data from 9311 tumor samples across 30 cancer types, we developed a novel tool called the modulator of TMB-associated immune infiltration (MOTIF), which comprises genes that can determine the extent of CD8+ T cell infiltration prompted by a certain TMB level. We confirmed that MOTIF can accurately reflect the integrity and defects of the cancer-immunity cycle. By analyzing 84 human single-cell RNA-seq datasets from 32 types of solid tumors, we revealed that MOTIF can provide insights into the diverse roles of various cell types in the modulation of CD8+ T cell infiltration. Using pretreatment RNA-seq data from 13 ICI-treated cohorts, we validated the use of MOTIF in predicting CD8+ T cell infiltration and ICI efficacy. Among the components of MOTIF, we identified EMC3 as a negative regulator of CD8+ T cell infiltration, which was validated via in vivo studies. Additionally, MOTIF provided guidance for the potential combinations of programmed death 1 blockade with certain immunostimulatory drugs to facilitate CD8+ T cell infiltration and improve ICI efficacy.

Recent advances in cancer-associated fibroblast: Biomarkers, signaling pathways, and therapeutic opportunities

ABSTRACT

Anti-cancer therapies usually focus on tumor cells, but non-tumor stromal components in the tumor microenvironment also play vital roles in tumor initiation and progression, which may be the prognostic factors and potential therapeutic targets. Cancer-associated fibroblasts (CAFs) are the essential component in the tumor environment, exhibiting high heterogeneity in their cell origin and phenotype with diverse functions that influence tumor angiogenesis, immune systems, and metabolism. Single-cell RNA sequencing and genetically engineered mouse models have increased our understanding of CAF diversity, and many subtypes have been defined. However, the precise functions of these subtypes need to be studied and validated. Studies of signaling pathways and epigenetic changes in CAFs facilitate understanding of the phenotypes of CAFs and the crosstalk between tumor cells and CAFs to provide potential therapeutic targets. Some clinical trials, including phase III trials targeting CAFs, have been performed recently. However, few of these trials have generated promising results, which indicates that the complexity of CAFs in the tumor microenvironment remains largely unknown, and in-depth investigations of CAFs should be performed. This review summarizes the research on CAFs, focusing on the heterogeneity of their phenotypes and functions, specific signaling pathways, and the therapeutic strategies involving CAFs. Additionally, we briefly discuss the current technologies commonly used in CAF studies and describe the challenges and future perspectives of CAF research.

Potential anti-tumor effects of regulatory T cells in the tumor microenvironment: a review

Regulatory T cells (Tregs) expressing the transcription factor FoxP3 are essential for maintaining immunological balance and are a significant component of the immunosuppressive tumor microenvironment (TME). Single-cell RNA sequencing (ScRNA-seq) technology has shown that Tregs exhibit significant plasticity and functional diversity in various tumors within the TME. This results in Tregs playing a dual role in the TME, which is not always centered around supporting tumor progression as typically believed. Abundant data confirms the anti-tumor activities of Tregs and their correlation with enhanced patient prognosis in specific types of malignancies. In this review, we summarize the potential anti-tumor actions of Tregs, including suppressing tumor-promoting inflammatory responses and boosting anti-tumor immunity. In addition, this study outlines the spatial and temporal variations in Tregs function to emphasize that their predictive significance in malignancies may change. It is essential to comprehend the functional diversity and potential anti-tumor effects of Tregs to improve tumor therapy strategies.

Intercellular crosstalk between cancer cells and cancer-associated fibroblasts via exosomes in gastrointestinal tumors

Gastrointestinal (GI) tumors are a significant global health threat, with high rates of morbidity and mortality. Exosomes contain various biologically active molecules like nucleic acids, proteins, and lipids and can serve as messengers for intercellular communication. They play critical roles in the exchange of information between tumor cells and the tumor microenvironment (TME). The TME consists of mesenchymal cells and components of the extracellular matrix (ECM), with fibroblasts being the most abundant cell type in the tumor mesenchyme. Cancer-associated fibroblasts (CAFs) are derived from normal fibroblasts and mesenchymal stem cells that are activated in the TME. CAFs can secrete exosomes to modulate cell proliferation, invasion, migration, drug resistance, and other biological processes in tumors. Additionally, tumor cells can manipulate the function and behavior of fibroblasts through direct cell-cell interactions. This review provides a summary of the intercellular crosstalk between GI tumor cells and CAFs through exosomes, along with potential underlying mechanisms.

Tumor stroma ratio, tumor stroma maturity, tumor-infiltrating immune cells in relation to prognosis, and neoadjuvant therapy response in esophagogastric junction adenocarcinoma

Accurate predictions on prognosis and neoadjuvant therapy response are crucial for esophagogastric junction adenocarcinoma (EGJA) patients. Therefore, we aimed to investigate the predictive abilities of several indicators, including tumor stroma ratio (TSR), tumor stroma maturity (TSM), and the density and spatial distribution of tumor-infiltrating immune cells (TIICs), such as T cells, B cells, and tumor-associated macrophages (TAMs). Resection and biopsy specimens of a total of 695 patients were included, obtained from the National Cancer Center (NCC) and The Cancer Genome Atlas (TCGA) cohorts. TSR and TSM were evaluated based on histological assessment. TIICs were quantified by QuPath following immunohistochemical (IHC) staining in resection specimens, while the Klintrup-Mäkinen (KM) grade was employed for evaluating TIIC in biopsy specimens. Patients with high stromal levels or immature stroma had relatively worse prognoses. Furthermore, high CD8+T cell count in the tumor periphery, as well as low CD68+ TAM count either in the tumor center or in the tumor periphery, was an independent favorable prognostic factor. Significantly, the combination model incorporating TSM and CD163+TAMs emerged as an independent prognostic factor in both two independent cohorts (HR 3.644, 95% CI 1.341-9.900, p = 0.011 and HR 1.891, 95% CI 1.195-2.99, p = 0.006, respectively). Additionally, high stromal levels in preoperative biopsies correlated with poor neoadjuvant therapy response (p < 0.05). In conclusion, our findings suggest that TSR, TSM, CD8+T cell, CD68+TAMs, and CD163+TAMs predict the prognosis to some extent in patients with EGJA. Notably, the combined model incorporating TSM and CD163+TAM can contribute significantly to prognostic stratification. Additionally, high stromal levels evaluated in preoperative biopsy specimens correlated with poor neoadjuvant therapy response.

Understanding Cancer's Defense against Topoisomerase-Active Drugs: A Comprehensive Review

In recent years, the emergence of cancer drug resistance has been one of the crucial tumor hallmarks that are supported by the level of genetic heterogeneity and complexities at cellular levels. Oxidative stress, immune evasion, metabolic reprogramming, overexpression of ABC transporters, and stemness are among the several key contributing molecular and cellular response mechanisms. Topo-active drugs, e.g., doxorubicin and topotecan, are clinically active and are utilized extensively against a wide variety of human tumors and often result in the development of resistance and failure to therapy. Thus, there is an urgent need for an incremental and comprehensive understanding of mechanisms of cancer drug resistance specifically in the context of topo-active drugs. This review delves into the intricate mechanistic aspects of these intracellular and extracellular topo-active drug resistance mechanisms and explores the use of potential combinatorial approaches by utilizing various topo-active drugs and inhibitors of pathways involved in drug resistance. We believe that this review will help guide basic scientists, pre-clinicians, clinicians, and policymakers toward holistic and interdisciplinary strategies that transcend resistance, renewing optimism in the ongoing battle against cancer.

Development and verification of a combined immune- and cancer-associated fibroblast related prognostic signature for colon adenocarcinoma

Introduction

To better understand the role of immune escape and cancer-associated fibroblasts (CAFs) in colon adenocarcinoma (COAD), an integrative analysis of the tumor microenvironment was performed using a set of 12 immune- and CAF-related genes (ICRGs).

Methods

Univariate and least absolute shrinkage and selection operator (LASSO) Cox regression analyses were used to establish a prognostic signature based on the expression of these 12 genes (S1PR5, AEN, IL20RB, FGF9, OSBPL1A, HSF4, PCAT6, FABP4, KIF15, ZNF792, CD1B and GLP2R). This signature was validated in both internal and external cohorts and was found to have a higher C-index than previous COAD signatures, confirming its robustness and reliability. To make use of this signature in clinical settings, a nomogram incorporating ICRG signatures and key clinical parameters, such as age and T stage, was developed. Finally, the role of S1PR5 in the immune response of COAD was validated through in vitro cytotoxicity experiments.

Results

The developed nomogram exhibited slightly improved predictive accuracy compared to the ICRG signature alone, as indicated by the areas under the receiver operating characteristic curves (AUC, nomogram:0.838; ICRGs:0.807). The study also evaluated the relationships between risk scores (RS) based on the expression of the ICRGs and other key immunotherapy variables, including immune checkpoint expression, immunophenoscore (IPS), and microsatellite instability (MSI). Integration of these variables led to more precise prediction of treatment efficacy, enabling personalized immunotherapy for COAD patients. Knocking down S1PR5 can enhance the efficacy of PD-1 monoclonal antibody, promoting the cytotoxicity of T cells against HCT116 cells ((p<0.05).

Discussion

These findings indicate that the ICRG signature may be a valuable tool for predicting prognostic risk, evaluating the efficacy of immunotherapy, and tailoring personalized treatment options for patients with COAD.

Immune infiltration and clinical significance analyses of the cancer-associated fibroblast-related signature in skin cutaneous melanoma

BACKGROUND

Skin cutaneous melanoma (SKCM) is one of the most aggressive cancers with high mortality rates. Cancer-associated fibroblasts (CAFs) play essential roles in tumor growth, metastasis and the establishment of a pro-tumor microenvironment. This study aimed to establish a CAF-related signature for providing a new perspective for indicating prognosis and guiding therapeutic regimens of SKCM patients.

METHODS

In this study, the CAF-related genes were screened out based on melanoma-associated fibroblast markers identified from single-cell transcriptome analysis in the Gene Expression Omnibus (GEO) database and a CAF-related module identified from weighted gene co-expression analysis using The Cancer Genome Atlas (TCGA) dataset. We extracted these gene expression data of SKCM samples from TCGA and constructed a prognostic CAF-related signature. The prediction abilities of the signature for survival prognosis, tumor immune landscape and responses to chemo-/immunotherapies were evaluated in the TCGA-SKCM cohort.

RESULTS

We suggested that CAFs were significantly involved in the clinical outcomes of SKCM. A 10-gene CAF-related model was constructed, and the high-CAF risk group exhibited immunosuppressive features and worse prognosis. Patients with high CAF score were more likely to not respond to immune checkpoint inhibitors but were more sensitive to some chemotherapeutic agents, suggesting a potential approach of chemotherapy/anti-CAF combination treatment to improve the SKCM patient response rate of current immunotherapies.

CONCLUSIONS

The CAF-related risk score could serve as a robust prognostic indicator and personal assessment of this score could uncover the degree of immunosuppression and provide treatment strategies to improve outcomes in clinical decision-making in SKCM patients.

[Patterns of CAF expression in tumors of the genitourinary system]

Cancer-associated fibroblasts (CAF), as the most important component of the tumor microenvironment, have been the subject of targeted study in recent years. There is increasing evidence of CAF heterogeneity and their different roles in tumor progression. However, there is no single marker identifying CAF, and there is also no understanding of the similarity of CAF markers in various tumors of the genitourinary system.

OBJECTIVE

To evaluate the response of CAF markers - FAP and PDGFRα+β in bladder cancer and prostate cancer.

MATERIAL AND METHODS

An immunohistochemical study with antibodies to FAP and PDGFRα+β was conducted on material from 34 patients with prostate cancer and 44 patients with bladder cancer in order to identify statistical relationships with stage, morphological characteristics and survival, as well as to understand the applicability of the same markers for cancer of different localizations.

RESULTS

An increased FAP reaction was shown in prostate cancer with metastases (p=0.0239), a significantly higher number of recurrences in the group with a high PDGFRa+β (3+) reaction (p=0.0018); the presence of FAP reaction only in invasive bladder cancers (p=0.0094) and bladder cancers with high grade dysplasia (p=0.0000234), the absence of a relationship between the level of PDGFRa+β and clinical and morphological characteristics in bladder cancer.

CONCLUSION

Our results confirm the heterogeneity of CAF in both bladder and prostate tumors and indicate that FAP is one of CAF subpopulation marker.

Considering that FAP is expressed in a population of CAFs that lead to resistance to treatment with immune checkpoint inhibitors in melanoma, the FAP marker may also be diagnostically significant for tumors of the genitourinary system, especially given the fact that bladder tumors are treated with the BCG vaccine.