Mechanisms of vasculogenic mimicry in hypoxic tumor microenvironments

Interference of FZD2 suppresses proliferation, vasculogenic mimicry and stemness in glioma cells via blocking the Notch/NF‑κB signaling pathway

Frizzled family protein 2 (FZD2) is widely associated with tumor development and metastasis. The present study aimed to gain an insight into the role and regulatory mechanism of FZD2 in glioma. The expression level of FZD2 in normal astrocyte and glioma cells was determined by reverse transcription-quantitative PCR and western blotting, and cell transfection was conducted for FZD2 expression knockdown. Malignant behaviors including cell proliferation, migration and invasion, vasculogenic mimicry (VM) and cell stemness were determined using Cell Counting Kit-8, 5-Ethynyl-2'-deoxyuridine (EdU) staining, colony formation, wound healing, Transwell, 3D culturing and sphere formation assays. The expression levels of proteins related to stemness, epithelial-mesenchymal transition (EMT) and Notch/NF-κB signaling were measured by western blotting. Then, the Notch agonist, Jagged-1 (JAG), was adopted for rescue experiments. The results demonstrated that FZD2 was highly expressed in glioma cells. Interference of FZD2 expression suppressed the proliferation of glioma cells, as evidenced by the reduced cell viability and the number of EdU+ cells and colonies. Meanwhile, the reduced sphere formation ability and decreased protein expression of Nanog, Sox2 and Oct4 following FZD2 knockdown confirmed that FZD2 repressed cell stemness in glioma. Additionally, FZD2 knockdown suppressed the migration, invasion, EMT and VM formation capabilities of glioma cells, and also blocked the Notch/NF-κB signaling pathway. Furthermore, activation of Notch by JAG treatment partially reversed the aforementioned FZD2 knockdown-mediated changes in glioma cell malignant behaviors. In conclusion, FZD2 may contribute to glioma progression through activating the Notch/NF-κB signaling pathway, providing a plausible therapeutic target for the treatment of glioma.

Juglone suppresses vasculogenic mimicry in glioma through inhibition of HuR-mediated VEGF-A expression

Vasculogenic mimicry (VM) serves as a vascular-like channel that provides important substances for tumor growth and is a primary factor in glioblastoma (GBM) drug resistance. Human Antigen R (HuR)-an mRNA-binding protein-is highly expressed in GBM, closely related to tumor progression, and deemed a potential drug target. Although some small-molecule compounds have been identified to disrupt HuR binding to target mRNA, they remain in the preclinical research stage, suggesting the need for further validation and development of HuR inhibitors. In our study, we aim to screen for potential HuR inhibitors and investigate their efficacy and molecular mechanisms in GBM. We employed the fluorescence polarization method to identify HuR inhibitors from a natural compound library, confirming the efficacy of juglone in effectively inhibiting the binding of HuR to AREVegf-a. Further validation of the binding of juglone to HuR at the protein level was conducted through electrophoretic mobility shift analysis, surface plasmon resonance, and molecular docking. Furthermore, juglone demonstrated inhibitory effects on glioma growth and VM formation in vitro and in vivo. Moreover, it was observed that juglone reversed epithelial-mesenchymal transition by inhibiting the VEGF-A/VEGFR2/AKT/SNAIL signaling pathway. Finally, we established the capability of juglone to target HuR in U251 cells through HuR knockdown, mRNA stability, and cell thermal shift assays. Therefore, this study identifies juglone as a novel HuR inhibitor, potentially offering promise as a lead compound for anti-VM therapy in GBM by targeting HuR. Abbreviations: AKT, protein kinase B; ARE, adenine-and uridine-rich elements; CETSA, cellular thermal shift assay; DMEM, Dulbecco's modified Eagle's medium; ELISA, enzyme linked immune sorbent assay; EMSA, electrophoretic mobility shift assay; EMT, epithelial mesenchymal transition; FP, fluorescence polarization; GBM, glioblastoma; HTS, high-throughput screening; HuR, human antigen R; IF, Immunofluorescence; PAS, periodic acid-Schiff; PI3K, phosphoinositide-3 kinase; qRT-PCR, quantitative real-time PCR; RRMs, RNA recognition motifs; SPR, surface plasmon resonance. TMZ, temozolomide; VM, vasculogenic mimicry; VEGF-A, Vascular endothelial growth factor-A; VEGFR2, Vascular endothelial growth factor receptor-2.

Acidity-targeting transition-aided universal chimeric antigen receptor T-cell (ATT-CAR-T) therapy for the treatment of solid tumors

The use of CAR-T cells in treating solid tumors frequently faces significant challenges, mainly due to the heterogeneity of tumor antigens. This study assessed the efficacy of an acidity-targeting transition-aided universal chimeric antigen receptor T (ATT-CAR-T) cell strategy, which is facilitated by an acidity-targeted transition. Specifically, the EGFRvIII peptide was attached to the N-terminus of a pH-low insertion peptide. Triggered by the acidic conditions of the tumor microenvironment, this peptide alters its structure and selectively integrates into the membrane of solid tumor cells. The acidity-targeted transition component effectively relocated the EGFRvIII peptide across various tumor cell membranes; thus, allowing the direct destruction of these cells by EGFRvIII-specific CAR-T cells. This method was efficient even when endogenous antigens were absent. In vivo tests showed marked antigen modification within the acidic tumor microenvironment using this component. Integrating this component with CAR-T cell therapy showed high effectiveness in combating solid tumors. These results highlight the capability of ATT-CAR-T cell therapy to address the challenges presented by tumor heterogeneity and expand the utility of CAR-T cell therapy in the treatment of solid tumors.

Comparative time-series multi-omics analyses suggest H1.2 involvement in anoxic adaptation and cancer resistance

The naked mole rat (NMR), Heterocephalus glaber, is known as the longest-lived rodent and is extraordinarily resistant to hypoxia and cancer. Here, both NMR embryonic fibroblasts (NEFs) and their mouse counterparts (MEFs) were subjected to anoxic conditions (0% O2, 5% CO2). A combination of comparative transcriptomics and proteomics was then employed to identify differentially expressed genes (DEGs). Notably, we observed distinct levels of histone H1.2 (encoded by HIST1H1C) accumulation between NEFs and MEFs. Subsequent mechanistic analyses showed that higher H1.2 expression in NEFs was associated with the lower expression of its inhibitor, PARP1. Additionally, we discovered that H1.2 can directly interact with HIF-1α PAS domains, thereby promoting the expression of HIF-1α through facilitating the dimerization with HIF-1β. The overexpression of H1.2 was also found to trigger autophagy and to suppress the migration of cancer cells, as well as the formation of xenograft tumors, via the NRF2/P62 signaling pathway. Moreover, an engineered H1.2 knock-in mouse model exhibited significantly extended survival in hypoxic conditions (4% O2) and showed a reduced rate of tumor formation. Collectively, our results indicate a potential mechanistic link between H1.2 and the dual phenomena of anoxic adaptation and cancer resistance.

Research progress on the use of Salvia miltiorrhiza Bunge extracts in the treatment of pulmonary diseases

Salvia miltiorrhiza Bunge extracts, known for their diverse biological activities, often have remarkable efficacy in treating pulmonary diseases overlooked due to their specific cardiovascular actions. With the recent outbreak of COVID-19, research into pulmonary-related diseases has garnered significant attention. Salvia miltiorrhiza Bunge extracts can be broadly categorized into lipophilic and hydrophilic components; however, a comprehensive summary of their mechanisms in treating pulmonary diseases is lacking. Therefore, this review aims to systematically summarize the therapeutic mechanisms of 10 major Salvia miltiorrhiza Bunge extracts in treating pulmonary fibrosis, lung cancer, acute lung injury, and chronic obstructive pulmonary disease, with the goal of identifying promising options for efficacious therapies.

Hypoxia-Driven Changes in Tumor Microenvironment: Insights into Exosome-Mediated Cell Interactions

Hypoxia, as a prominent feature of the tumor microenvironment, has a profound impact on the multicomponent changes within this environment. Under hypoxic conditions, the malignant phenotype of tumor cells, the variety of cell types within the tumor microenvironment, as well as intercellular communication and material exchange, undergo complex alterations. These changes provide significant prospects for exploring the mechanisms of tumor development under different microenvironmental conditions and for devising therapeutic strategies. Exosomes secreted by tumor cells and stromal cells are integral components of the tumor microenvironment, serving as crucial mediators of intercellular communication and material exchange, and have consequently garnered increasing attention from researchers. This review focuses on the mechanisms by which hypoxic conditions promote the release of exosomes by tumor cells and alter their encapsulated contents. It also examines the effects of exosomes derived from tumor cells, immune cells, and other cell types under hypoxic conditions on the tumor microenvironment. Additionally, we summarize current research progress on the potential clinical applications of exosomes under hypoxic conditions and propose future research directions in this field.

Cellular and molecular mechanisms of gastrointestinal cancer liver metastases and drug resistance

Distant metastases and drug resistance account for poor survival of patients with gastrointestinal (GI) malignancies such as gastric cancer, pancreatic cancer, and colorectal cancer. GI cancers most commonly metastasize to the liver, which provides a unique immunosuppressive tumour microenvironment to support the development of a premetastatic niche for tumor cell colonization and metastatic outgrowth. Metastatic tumors often exhibit greater resistance to drugs than primary tumors, posing extra challenges in treatment. The liver metastases and drug resistance of GI cancers are regulated by complex, intertwined, and tumor-dependent cellular and molecular mechanisms that influence tumor cell behavior (e.g. epithelial-to-mesenchymal transition, or EMT), tumor microenvironment (TME) (e.g. the extracellular matrix, cancer-associated fibroblasts, and tumor-infiltrating immune cells), tumor cell-TME interactions (e.g. through cytokines and exosomes), liver microenvironment (e.g. hepatic stellate cells and macrophages), and the route and mechanism of tumor cell dissemination (e.g. circulating tumor cells). This review provides an overview of recent advances in the research on cellular and molecular mechanisms that regulate liver metastases and drug resistance of GI cancers. We also discuss recent advances in the development of mechanism-based therapy for these GI cancers. Targeting these cellular and molecular mechanisms, either alone or in combination, may potentially provide novel approaches to treat metastatic GI malignancies.

Beyond the Gut: The intratumoral microbiome's influence on tumorigenesis and treatment response

The intratumoral microbiome (TM) refers to the microorganisms in the tumor tissues, including bacteria, fungi, viruses, and so on, and is distinct from the gut microbiome and circulating microbiota. TM is strongly associated with tumorigenesis, progression, metastasis, and response to therapy. This paper highlights the current status of TM. Tract sources, adjacent normal tissue, circulatory system, and concomitant tumor co-metastasis are the main origin of TM. The advanced techniques in TM analysis are comprehensively summarized. Besides, TM is involved in tumor progression through several mechanisms, including DNA damage, activation of oncogenic signaling pathways (phosphoinositide 3-kinase [PI3K], signal transducer and activator of transcription [STAT], WNT/β-catenin, and extracellular regulated protein kinases [ERK]), influence of cytokines and induce inflammatory responses, and interaction with the tumor microenvironment (anti-tumor immunity, pro-tumor immunity, and microbial-derived metabolites). Moreover, promising directions of TM in tumor therapy include immunotherapy, chemotherapy, radiotherapy, the application of probiotics/prebiotics/synbiotics, fecal microbiome transplantation, engineered microbiota, phage therapy, and oncolytic virus therapy. The inherent challenges of clinical application are also summarized. This review provides a comprehensive landscape for analyzing TM, especially the TM-related mechanisms and TM-based treatment in cancer.

Functional roles of microRNAs in vasculogenic mimicry and resistance to therapy in human cancers: an update

INTRODUCTION

Vasculogenic mimicry (VM) alludes to the ability of cancer cells to organize on three-dimensional channel-like structures to obtain nutrients and oxygen. This mechanism confers an aggressive phenotype, metastatic potential, and resistance to chemotherapy resulting in a poor prognosis. Recent studies have been focused on the identification of microRNAs (miRNAs) that regulate the VM representing potential therapeutic targets in cancer.

AREAS COVERED

An overview of the roles of miRNAs on VM development and their functional relationships with tumor microenvironment. The functions of cancer stem-like cells in VM, and resistance to therapy are also discussed. Moreover, the modulation of VM by natural compounds is explored. The clinical significance of deregulated miRNAs as potential therapeutic targets in tumors showing VM is further highlighted.

EXPERT OPINION

The miRNAs are regulators of protein-encoding genes involved in VM; however, their specific expression signatures with clinical value in large cohorts of patients have not been established yet. We considered that genomic profiling of miRNAs could be useful to define some hallmarks of tumors such as stemness, drug resistance, and VM in cancer patients. However, additional studies are needed to establish the relevant role of miRNAs as effective therapeutic targets in tumors that have developed VM.

The in vitro dynamics of pseudo-vascular network formation

BACKGROUND/OBJECTIVES

Pseudo-vascular network formation in vitro is considered a key characteristic of vasculogenic mimicry. While many cancer cell lines form pseudo-vascular networks, little is known about the spatiotemporal dynamics of these formations.

METHODS

Here, we present a framework for monitoring and characterising the dynamic formation and dissolution of pseudo-vascular networks in vitro. The framework combines time-resolved optical microscopy with open-source image analysis for network feature extraction and statistical modelling. The framework is demonstrated by comparing diverse cancer cell lines associated with vasculogenic mimicry, then in detecting response to drug compounds proposed to affect formation of vasculogenic mimics. Dynamic datasets collected were analysed morphometrically and a descriptive statistical analysis model was developed in order to measure stability and dissimilarity characteristics of the pseudo-vascular networks formed.

RESULTS

Melanoma cells formed the most stable pseudo-vascular networks and were selected to evaluate the response of their pseudo-vascular networks to treatment with axitinib, brucine and tivantinib. Tivantinib has been found to inhibit the formation of the pseudo-vascular networks more effectively, even in dose an order of magnitude less than the two other agents.

CONCLUSIONS

Our framework is shown to enable quantitative analysis of both the capacity for network formation, linked vasculogenic mimicry, as well as dynamic responses to treatment.

Vascular mimicry in zebrafish fin regeneration: how macrophages build new blood vessels

Vascular mimicry has been thoroughly investigated in tumor angiogenesis. In this study, we demonstrate for the first time that a process closely resembling tumor vascular mimicry is present during physiological blood vessel formation in tissue regeneration using the zebrafish fin regeneration assay. At the fin-regenerating front, vasculature is formed by mosaic blood vessels with endothelial-like cells possessing the morphological phenotype of a macrophage and co-expressing both endothelial and macrophage markers within single cells. Our data demonstrate that the vascular segments of the regenerating tissue expand, in part, through the transformation of adjacent macrophages into endothelial-like cells, forming functional, perfused channels and contributing to the de novo formation of microvasculature. Inhibiting the formation of tubular vascular-like structures by CVM-1118 prevents vascular mimicry and network formation resulting in a 70% shorter regeneration area with 60% reduced vessel growth and a complete absence of any signs of regeneration in half of the fin area. Additionally, this is associated with a significant reduction in macrophages. Furthermore, depleting macrophages using macrophage inhibitor PLX-3397, results in impaired tissue regeneration and blood vessel formation, namely a reduction in the regeneration area and vessel network by 75% in comparison to controls.

Ultra-pH-sensitive nanoparticle of gambogenic acid for tumor targeting therapy via anti-vascular strategy plus immunotherapy

Although the combination of anti-vascular strategy plus immunotherapy has emerged as the optimal first-line treatment of hepatocellular carcinoma, lack of tumor targeting leads to low antitumor efficacy and serious side effect. Here, we report an ultra-pH-sensitive nanoparticle of gambogenic acid (GNA) encapsulated by poly(ethylene glycol)-poly(2-azepane ethyl methacrylate) (PEG-PAEMA) for tumor-targeting combined therapy of anti-vascular strategy plus immunotherapy. PEG-PAEMA-GNA nanoparticle was quite stable at pH 7.4 for 30 d. In contrast, it exerted size shrinkage, charge reversal and the release of GNA at pH 6.7 within 24 h. Moreover, PEG-PAEMA-GNA significantly enhanced the anti-vascular activity, membrane-disruptive capability and pro-apoptosis when pH changed from 7.4 to 6.7. Western blot analysis exhibits that PEG-PAEMA and its GNA nanoparticle facilitated the phosphorylation of STING protein. In vivo assays show that PEG-PAEMA-GNA not only displayed much higher tumor inhibition of 92 % than 37 % of free GNA, but also inhibited tumor vasculature, promoted the maturation of dendritic cells and recruited more cytotoxic t-lymphocytes for sufficient anti-vascular therapy and immunotherapy. All these results demonstrate that PEG-PAEMA-GNA displayed tumor-targeting combined treatment of anti-vascular therapy and immunotherapy. This study offers a simple and novel method for the combination of anti-vascular therapy and immunotherapy with high selectivity towards tumor.

Cancer Immunotherapy with "Vascular-Immune" Crosstalk as Entry Point: Associated Mechanisms, Therapeutic Drugs and Nano-Delivery Systems

Tumor vessels characterized by abnormal functions and structures hinder the infiltration and immune antigen presentation of immune cells by inducing the formation of an immunosuppressive microenvironment ("cold" environment). Vascular-targeted therapy has been proven to enhance immune stimulation and the effectiveness of immunotherapy by modulating the "cold" microenvironment, such as hypoxia and an acidic microenvironment. Notably, a therapeutic strategy based on "vascular-immune" crosstalk can achieve dual regulation of tumor vessels and the immune system by reprogramming the tumor microenvironment (TME), thus forming a positive feedback loop between tumor vessels and the immune microenvironment. From this perspective, we discuss the factors of tumor angiogenesis and "cold" TME formation. Building on this foundation, some vascular-targeted therapeutic drugs will be elaborated upon in detail to achieve dual regulation of tumor vessels and immunity. More importantly, we focus on cutting-edge nanotechnology in view of "vascular-immune" crosstalk and discuss the rational fabrication of tailor-made nanosystems for efficiently enhancing immunotherapy.

Acidity and hypoxia of tumor microenvironment, a positive interplay in extracellular vesicle release by tumor cells

The complex and continuously evolving features of the tumor microenvironment, varying between tumor histotypes, are characterized by the presence of host cells and tumor cells embedded in a milieu shaped by hypoxia and low pH, resulting from the frequent imbalance between vascularity and tumor cell proliferation. These microenvironmental metabolic stressors play a crucial role in remodeling host cells and tumor cells, contributing to the stimulation of cancer cell heterogeneity, clonal evolution, and multidrug resistance, ultimately leading to progression and metastasis. The extracellular vesicles (EVs), membrane-enclosed structures released into the extracellular milieu by tumor/host cells, are now recognized as critical drivers in the complex intercellular communication between tumor cells and the local cellular components in a hypoxic/acidic microenvironment. Understanding the intricate molecular mechanisms governing the interactions between tumor and host cells within a hypoxic and acidic microenvironment, triggered by the release of EVs, could pave the way for innovative strategies to disrupt the complex interplay of cancer cells with their microenvironment. This approach may contribute to the development of an efficient and safe therapeutic strategy to combat cancer progression. Therefore, we review the major findings on the release of EVs in a hypoxic/acidic tumor microenvironment to appreciate their role in tumor progression toward metastatic disease.

Golgi Protein 73 Promotes Angiogenesis in Hepatocellular Carcinoma

Golgi protein 73 (GP73), a resident protein of the Golgi apparatus, is notably elevated in hepatocellular carcinoma (HCC). While its critical role in remodeling the tumor microenvironment (TME) is recognized, the intricate mechanisms are not fully understood. This study reveals that GP73 in HCC cells interacts with prolyl hydroxylase-2 (PHD-2) in a competitive manner, thereby impeding the hydroxylation of hypoxia-induced factor-1α (HIF-1α). The effect above promotes the production and secretion of vascular endothelial growth factor A (VEGFA). Moreover, exosomal GP73 derived from HCC cells can be internalized by human umbilical vein endothelial cells (HUVECs) and competitively interact with HECTD1, an E3 ubiquitin ligase targeting growth factor receptor-bound protein 2 (GRB2). This interaction stabilizes GRB2, thereby activating the Ras-mitogen-activated protein kinase (MAPK) signaling pathway. Consequently, escalated levels of GP73 intensify VEGF production in HCC cells and potentiate mitogenic signaling in vascular endothelial cells, fostering angiogenesis in the TME. Our findings propose that GP73 might serve as a novel target for anti-angiogenic therapy in HCC.

Amelioration of breast cancer therapies through normalization of tumor vessels and microenvironment: paradigm shift to improve drug perfusion and nanocarrier permeation

Breast cancer (BC) is the most commonly diagnosed cancer among women. Chemo-, immune- and photothermal therapies are employed to manage BC. However, the tumor microenvironment (TME) prevents free drugs and nanocarriers (NCs) from entering the tumor premises. Formulation scientists rely on enhanced permeation and retention (EPR) to extravasate NCs in the TME. However, recent research has demonstrated the inconsistent nature of EPR among different patients and tumor types. In addition, angiogenesis, high intra-tumor fluid pressure, desmoplasia, and high cell and extracellular matrix density resist the accumulation of NCs in the TME. In this review, we discuss TME normalization as an approach to improve the penetration of drugs and NCSs in the tumor premises. Strategies such as normalization of tumor vessels, reversal of hypoxia, alleviation of high intra-tumor pressure, and infiltration of lymphocytes for the reversal of therapy failure have been discussed in this manuscript. Strategies to promote the infiltration of anticancer immune cells in the TME after vascular normalization have been discussed. Studies strategizing time points to administer TME-normalizing agents are highlighted. Mechanistic pathways controlling the angiogenesis and normalization processes are discussed along with the studies. This review will provide greater tumor-targeting insights to the formulation scientists.

Vasorin Exocytosed from Glioma Cells Facilitates Angiogenesis via VEGFR2/AKT Signaling Pathway

Glioma is a highly vascularized tumor of the central nervous system. Angiogenesis plays a predominant role in glioma progression and is considered an important therapeutic target. Our previous study showed that vasorin (VASN), a transmembrane protein, is overexpressed in glioma and promotes angiogenesis; however, the potential mechanism remains unclear. In this study, we found that human vascular endothelial cells (hEC) co-cultured with VASN-overexpressing glioma cells exhibited accelerated migration ability and increased expression of VASN originated from glioma cells. VASN was found in exosomes secreted by glioma cells and could be taken up by hECs. hECs showed more edge filopodia and significantly upregulated expression of endothelial tip cell marker gene and protein levels after co-culture with VASN-overexpressing glioma cells. In clinical glioma tissue and orthotopic transplantation glioma tissue, the vascular density and the number of vascular endothelial cells with a tip cell phenotype in VASN-overexpressed tissues were significantly higher than in tissues with low expression. At the molecular level, VASN interacted with VEGFR2 and caused internalization and autophosphorylation of VEGFR2 protein, and then activated the AKT signaling pathway. Our study collectively reveals the function and mechanism of VASN in facilitating angiogenesis in glioma, providing a new therapeutic target for glioma.

IMPLICATIONS

These findings demonstrate that VASN exocytosed from glioma cells enhanced the migration of vascular endothelial cells by VEGFR2/AKT signaling pathway.

EIF4A3-Induced Circ_0059914 Promoted Angiogenesis and EMT of Glioma via the miR-1249/VEGFA Pathway

Gliomas are common brain tumors. Despite extensive research, the 5-year survival rate of glioma remains low. Many studies have reported that circular RNAs (circRNAs) play a role in promoting the malignant progression of glioma; however, the role of circ_0059914 in this process remains unclear. In this study, we aimed to investigate the function and underlying mechanism of circ_0059914 in glioma. Western blotting and qRT-PCR were used to determine the levels of circ_0059914, miR-1249, VEGFA, N-cadherin, vimentin, Snail, and EIF4A3. EDU and colony formation assays were conducted to evaluate cell proliferation. Transwell assays were used to explore cell migration and invasion and tube formation assays were used to analyze angiogenesis. RNA immunoprecipitation (RIP) and dual-luciferase reporter assays were used to explore the relationship between EIF4A3, circ_0059914, miR-1249, and VEGFA. A xenograft tumor assay was performed to determine the role of circ_0059914 in vivo. Circ_0059914 expression was upregulated in gliomas. Knockdown of gliomal circ_0059914 expression reduced the proliferation, migration, invasion, epithelial-mesenchymal transition (EMT), angiogenesis, and growth of glioma cells in vivo. Circ_0059914 sponged miR-1249, and miR-1249 inhibition reversed the circ_0059914 knockdown-mediated effects in glioma cells. VEGFA was found to be a target gene of miR1249; overexpression of VEGFA reversed the effect of miR-1249 up-regulation in glioma. Finally, EIF4A3 increased the expression of circ_0059914. EIF4A3-induced circ_0059914 expression plays a role in promoting glioma via the miR-1249/VEGFA axis.

Engineered in vivo and in vitro tumor model recapitulates vasculogenic mimicry signatures in melanoma

Vasculogenic mimicry (VM) describes a process by which tumor cells formed a novel microcirculation pattern in an endothelial cell-free manner. Clinically, VM is associated with aggressive phenotype and poor patient survival. However, the current models for investigating VM include 2D monolayer cultures, Matrigel-based cultures, and animal models, each of which has limitations. Matrigel-based models often exhibit batch-to-batch variations, while in vivo tumor models currently produce insufficient amounts of VM. There is currently no suitable tumor model to discover new therapeutic targets against VM. Herein, we establish an extracellular matrix (ECM)-based engineered tumor model in vivo and in vitro. In this study, we demonstrate that matrix proteins enhanced the VM formation in the engineered xenograft model. Furthermore, we also investigated the role of collagen/fibronectin (FN) in melanoma progression and VM formation. Compared with cells cultured on TCPS plates, the B16F10 cells cultured on collagen/FN coated plates showed increased proliferation and stemness, and significantly enhanced invasion and formation of VM networks. Molecular mechanism analysis showed that Integrin/VE-cadherin/EphA2/PI3K/MMP-2 signaling pathways are responsible for VM formation. Our results indicate that collagen/FN matrix plays an important role in VM formation in melanoma, suggesting that ECM protein is a potential therapeutic target for anti-VM therapy for melanoma.

The potential of vascular normalization for sensitization to radiotherapy

Radiotherapy causes apoptosis mainly through direct or indirect damage to DNA via ionizing radiation, leading to DNA strand breaks. However, the efficacy of radiotherapy is attenuated in malignant tumor microenvironment (TME), such as hypoxia. Tumor vasculature, due to the imbalance of various angiogenic and anti-angiogenic factors, leads to irregular morphology of tumor neovasculature, disordered arrangement of endothelial cells, and too little peripheral coverage. This ultimately leads to a TME characterized by hypoxia, low pH and high interstitial pressure. This deleterious TME further exacerbates the adverse effects of tumor neovascularization and weakens the efficacy of conventional radiotherapy. Whereas normalization of blood vessels improves TME and thus the efficacy of radiotherapy. In addition to describing the research progress of radiotherapy sensitization and vascular normalization, this review focuses on the strategy and application prospect of modulating vascular normalization to improve the efficacy of radiotherapy sensitization.

Lumbrokinase Extracted from Earthworms Synergizes with Bevacizumab and Chemotherapeutics in Treating Non-Small Cell Lung Cancer by Targeted Inactivation of BPTF/VEGF and NF-κB/COX-2 Signaling

As a kind of proteolytic enzyme extracted from earthworms, lumbrokinase has been used as an antithrombotic drug clinically. Nevertheless, its potential in anti-cancer, especially in anti-non-small cell lung cancer (NSCLC), as a single form of treatment or in combination with other therapies, is still poorly understood. In this study, we explored the anti-tumor role and the responsive molecular mechanisms of lumbrokinase in suppressing tumor angiogenesis and chemoresistance development in NSCLC and its clinical potential in combination with bevacizumab and chemotherapeutics. Lumbrokinase was found to inhibit cell proliferation in a concentration-dependent manner and caused metastasis suppression and apoptosis induction to varying degrees in NSCLC cells. Lumbrokinase enhanced the anti-angiogenesis efficiency of bevacizumab by down-regulating BPTF expression, decreasing its anchoring at the VEGF promoter region and subsequent VEGF expression and secretion. Furthermore, lumbrokinase treatment reduced IC50 values of chemotherapeutics and improved their cytotoxicity in parental and chemo-resistant NSCLC cells via inactivating the NF-κB pathway, inhibiting the expression of COX-2 and subsequent secretion of PGE2. LPS-induced NF-κB activation reversed its inhibition on NSCLC cell proliferation and its synergy with chemotherapeutic cytotoxicity, while COX-2 inhibitor celecoxib treatment boosted such effects. Lumbrokinase combined with bevacizumab, paclitaxel, or vincristine inhibited the xenograft growth of NSCLC cells in mice more significantly than a single treatment. In conclusion, lumbrokinase inhibited NSCLC survival and sensitized NSCLC cells to bevacizumab or chemotherapeutics treatment by targeted down-regulation of BPTF/VEGF signaling and inactivation of NF-κB/COX-2 signaling, respectively. The combinational applications of lumbrokinase with bevacizumab or chemotherapeutics are expected to be developed as promising candidate therapeutic strategies to improve the efficacy of the original monotherapy in anti-NSCLC.

Role of Protein Phosphatases in Tumor Angiogenesis: Assessing PP1, PP2A, PP2B and PTPs Activity

Tumor angiogenesis, the formation of new blood vessels to support tumor growth and metastasis, is a complex process regulated by a multitude of signaling pathways. Dysregulation of signaling pathways involving protein kinases has been extensively studied, but the role of protein phosphatases in angiogenesis within the tumor microenvironment remains less explored. However, among angiogenic pathways, protein phosphatases play critical roles in modulating signaling cascades. This review provides a comprehensive overview of the involvement of protein phosphatases in tumor angiogenesis, highlighting their diverse functions and mechanisms of action. Protein phosphatases are key regulators of cellular signaling pathways by catalyzing the dephosphorylation of proteins, thereby modulating their activity and function. This review aims to assess the activity of the protein tyrosine phosphatases and serine/threonine phosphatases. These phosphatases exert their effects on angiogenic signaling pathways through various mechanisms, including direct dephosphorylation of angiogenic receptors and downstream signaling molecules. Moreover, protein phosphatases also crosstalk with other signaling pathways involved in angiogenesis, further emphasizing their significance in regulating tumor vascularization, including endothelial cell survival, sprouting, and vessel maturation. In conclusion, this review underscores the pivotal role of protein phosphatases in tumor angiogenesis and accentuate their potential as therapeutic targets for anti-angiogenic therapy in cancer.

Selenium nanoparticles stabilized by Sargassum fusiforme polysaccharides: Synthesis, characterization and bioactivity

Selenium nanoparticles (SeNPs) are a potential tumor therapeutic drug and have attracted widespread attention due to their high bioavailability and significant anticancer activity. However, the poor water solubility and degradability of selenium nanoparticles severely limit their application. In this study, spherical selenium nanoparticles with a particle size of approximately 50 nm were prepared by using Sargassum fusiforme polysaccharide (SFPS) as a modifier and Tween-80 as a stabilizer. The results of in vitro experiments showed that Sargassum fusiforme polysaccharide-Tween-80-Selenium nanoparticles (SFPS-Tw-SeNPs) had a significant inhibitory effect on A549 cells, with an IC50 value of 6.14 μg/mL, and showed antitumor cell migration and invasion ability against A549 cells in scratch assays and cell migration and invasion assays (transwell assays). Western blot experiments showed that SFPS-Tw-SeNPs could inhibit the expression of tumor migration- and invasion-related proteins. These results suggest that SFPS-Tw-SeNPs may be potential tumor therapeutic agents, especially for the treatment of human lung cancer.

Vitamin D in tuberous sclerosis complex-associated tumors

Mammalian target of rapamycin inhibitors (mTORi) have been used to treat pediatric tuberous sclerosis complex (TSC)-associated tumors, particularly in cases with contraindications to surgery or difficulties in complete tumor resection. However, some patients experience side effects and tumor regression after discontinuation of the treatment. Therefore, there is an urgent need to develop drugs that can be used in combination with mTORi to increase their efficacy and minimize their side effects. 1,25-Dihydroxyvitamin D3 (1,25-D), which has anticancer properties, may be a promising candidate for adjuvant or alternative therapy because TSC and cancer cells share common mechanisms, including angiogenesis, cell growth, and proliferation. Vitamin D receptor-mediated signaling can be epigenetically modified and plays an important role in susceptibility to 1,25-D. Therefore, vitamin D signaling may be a promising drug target, and in vitro studies are required to evaluate the efficacy of 1,25-D in TSC-associated tumors, brain development, and core symptoms of psychiatric disorders.

Role of cancer stem cell ecosystem on breast cancer metastasis and related mouse models

Breast cancer metastasis is responsible for most breast cancer-related deaths and is influenced by many factors within the tumor ecosystem, including tumor cells and microenvironment. Breast cancer stem cells (BCSCs) constitute a small population of cancer cells with unique characteristics, including their capacity for self-renewal and differentiation. Studies have shown that BCSCs not only drive tumorigenesis but also play a crucial role in promoting metastasis in breast cancer. The tumor microenvironment (TME), composed of stromal cells, immune cells, blood vessel cells, fibroblasts, and microbes in proximity to cancer cells, is increasingly recognized for its crosstalk with BCSCs and role in BCSC survival, growth, and dissemination, thereby influencing metastatic ability. Hence, a thorough understanding of BCSCs and the TME is critical for unraveling the mechanisms underlying breast cancer metastasis. In this review, we summarize current knowledge on the roles of BCSCs and the TME in breast cancer metastasis, as well as the underlying regulatory mechanisms. Furthermore, we provide an overview of relevant mouse models used to study breast cancer metastasis, as well as treatment strategies and clinical trials addressing BCSC-TME interactions during metastasis. Overall, this study provides valuable insights for the development of effective therapeutic strategies to reduce breast cancer metastasis.

ESM1 enhances fatty acid synthesis and vascular mimicry in ovarian cancer by utilizing the PKM2-dependent warburg effect within the hypoxic tumor microenvironment

BACKGROUND

The hypoxic tumor microenvironment is a key factor that promotes metabolic reprogramming and vascular mimicry (VM) in ovarian cancer (OC) patients. ESM1, a secreted protein, plays an important role in promoting proliferation and angiogenesis in OC. However, the role of ESM1 in metabolic reprogramming and VM in the hypoxic microenvironment in OC patients has not been determined.

METHODS

Liquid chromatography coupled with tandem MS was used to analyze CAOV3 and OV90 cells. Interactions between ESM1, PKM2, UBA2, and SUMO1 were detected by GST pull-down, Co-IP, and molecular docking. The effects of the ESM1-PKM2 axis on cell glucose metabolism were analyzed based on an ECAR experiment. The biological effects of the signaling axis on OC cells were detected by tubule formation, transwell assay, RT‒PCR, Western blot, immunofluorescence, and in vivo xenograft tumor experiments.

RESULTS

Our findings demonstrated that hypoxia induces the upregulation of ESM1 expression through the transcription of HIF-1α. ESM1 serves as a crucial mediator of the interaction between PKM2 and UBA2, facilitating the SUMOylation of PKM2 and the subsequent formation of PKM2 dimers. This process promotes the Warburg effect and facilitates the nuclear translocation of PKM2, ultimately leading to the phosphorylation of STAT3. These molecular events contribute to the promotion of ovarian cancer glycolysis and vasculogenic mimicry. Furthermore, our study revealed that Shikonin effectively inhibits the molecular interaction between ESM1 and PKM2, consequently preventing the formation of PKM2 dimers and thereby inhibiting ovarian cancer glycolysis, fatty acid synthesis and vasculogenic mimicry.

CONCLUSION

Our findings demonstrated that hypoxia increases ESM1 expression through the transcriptional regulation of HIF-1α to induce dimerization via PKM2 SUMOylation, which promotes the OC Warburg effect and VM.

The biological behavior and clinical outcome of pituitary adenoma are affected by the microenvironment

BACKGROUND

Pituitary adenoma is one of the most common brain tumors. Most pituitary adenomas are benign and can be cured by surgery and/or medication. However, some pituitary adenomas show aggressive growth with a fast growth rate and are resistant to conventional treatments such as surgery, drug therapy, and radiation therapy. These tumors, referred to as refractory pituitary adenomas, often relapse or regrow in the early postoperative period. The tumor microenvironment (TME) has recently been identified as an important factor affecting the biological manifestations of tumors and acts as the main battlefield between the tumor and the host immune system.

MAIN BODY

In this review, we focus on describing TME in pituitary adenomas and refractory pituitary adenomas. Research on the immune microenvironment of pituitary adenomas is currently focused on immune cells such as macrophages and lymphocytes, and extensive research and experimental verifications are still required regarding other components of the TME. In particular, studies are needed to determine the role of the TME in the specific biological behaviors of refractory pituitary adenomas, such as high invasion, fast recurrence rate, and high tolerance to traditional treatments and to identify the mechanisms involved.

CONCLUSION

Overall, we summarize the similarities and differences between the TME of pituitary adenomas and refractory pituitary adenomas as well as the changes in the biological behavior of pituitary adenomas that may be caused by the microenvironment. These changes greatly affect the outcome of patients.

Vasculogenic mimicry regulates immune infiltration and mutational status of the tumor microenvironment in breast cancer to influence tumor prognosis

BACKGROUND

Vasculogenic mimicry (VM) refers to the direct formation of microcirculatory ducts by invasive malignant tumors via cellular phenotypic transformation. However, there is a lack of VM-based biomarkers for breast cancer.

METHODS

We obtained transcriptomic expression data, single cell sequencing data, and clinical data of patients from The Cancer Genome Atlas Program (TCGA) database and GEO database, performed single cell analysis to obtain specific type annotations of breast cancer cells and analyzed their spatial expression analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) and gene ontology (GO) analyses as well as Gene Set Enrichment Analysis (GSEA) analyses were performed to clarify the biological pathways and tumor functional enrichment relationships of the major expressed genes of VM in the breast cancer bulk data specimens. VM biomarkers were constructed. Meanwhile, the relationship between VM scores and tumor immune infiltration in breast cancer was analyzed using MCPcounter and ssGSEA methods. In addition, we assessed the specific relationship between NDRG1, a key VM gene in breast cancer, and tumor colonization, adhesion and invasion by biological experiments in breast cancer cell lines.

RESULTS

The main cell types of breast cancer (BRCA) samples were annotated by single cell transcriptome analysis. Most of the VM-high group was present in epithelial cells, whereas the VM-low group was present in immune and stromal cells. Multiple tumor pathways such as TGFβ p53 and MAPK were closely associated with VM-mediated breast cancer infiltration and invasion. A prognostic model of breast cancer based on VM key genes was constituted. Prognostic stratification of breast cancer was successfully achieved for the TCGA-BRCA and GSE58812 datasets. Through immune infiltration analysis, we found that differential expression of VM markers was associated with multiple immune cell regulation. In MDA-MB-231 and MDA-MB-453 cell lines, we found that the NDRG1 gene significantly promoted colony formation of breast cancer cells.

CONCLUSION

Our constructed VM-related gene-based model of breast cancer biology holds promise for prognostic prediction and patient stratification of breast cancer. This may provide a potentially clinically valuable aid in promoting a deeper understanding of the biological regulation of VM in breast cancer and exploring the specific mechanisms of tumor angiogenesis and breast cancer development.

Exosomes derived from pulmonary metastatic sites enhance osteosarcoma lung metastasis by transferring the miR-194/215 cluster targeting MARCKS

Osteosarcoma, a prevalent primary malignant bone tumor, often presents with lung metastases, severely impacting patient survival rates. Extracellular vesicles, particularly exosomes, play a pivotal role in the formation and progression of osteosarcoma-related pulmonary lesions. However, the communication between primary osteosarcoma and exosome-mediated pulmonary lesions remains obscure, with the potential impact of pulmonary metastatic foci on osteosarcoma progression largely unknown. This study unveils an innovative mechanism by which exosomes originating from osteosarcoma pulmonary metastatic sites transport the miR-194/215 cluster to the primary tumor site. This transportation enhances lung metastatic capability by downregulating myristoylated alanine-rich C-kinase substrate (MARCKS) expression. Addressing this phenomenon, in this study we employ cationic bovine serum albumin (CBSA) to form nanoparticles (CBSA-anta-194/215) via electrostatic interaction with antagomir-miR-194/215. These nanoparticles are loaded into nucleic acid-depleted exosomal membrane vesicles (anta-194/215@Exo) targeting osteosarcoma lung metastatic sites. Intervention with bioengineered exosome mimetics (anta-194/215@Exo) not only impedes osteosarcoma progression but also significantly prolongs the lifespan of tumor-bearing mice. These findings suggest that pulmonary metastatic foci-derived exosomes initiate primary osteosarcoma lung metastasis by transferring the miR-194/215 cluster targeting MARCKS, making the miR-194/215 cluster a promising therapeutic target for inhibiting the progression of patients with osteosarcoma lung metastases.

An oral bioactive chitosan-decorated doxorubicin nanoparticles/bacteria bioconjugates enhance chemotherapy efficacy in an in-situ breast cancer model

Breast cancer is the second leading cause of cancer-related deaths among women worldwide. Despite significant advancements in chemotherapy, its effectiveness is often limited by poor drug distribution and systemic toxicity caused by the weak targeting ability of conventional therapeutic agents. The hypoxic tumor microenvironment (TME) also plays a vital role in treatment outcomes. Oral anticancer therapeutic agents have gained popularity and show promising results due to their ease of repeated administration. This study introduces autopilot biohybrids (Bif@BDC-NPs) for the effective delivery of doxorubicin (DOX) to the tumor site. This hybrid combines albumin-encapsulated DOX nanoparticles (BD-NPs) coated with chitosan (CS) for breast cancer chemotherapy, along with anaerobic Bifidobacterium infantis (B. infantis, Bif) serving as self-propelled motors. Due to Bif's specific anaerobic properties, Bif@BDC-NPs precisely anchor hypoxic regions of tumor tissue and significantly increase drug accumulation at the tumor site, thereby promoting tumor cell death. In an in-situ mouse breast cancer model, Bif@BDC-NPs achieved 94 % tumor inhibition, significantly prolonging the median survival of mice to 62 days, and reducing the toxic side effects of DOX. Therefore, the new bacteria-driven oral drug delivery system, Bif@BDC-NPs, overcomes multiple physiological barriers and holds great potential for the precise treatment of solid tumors.

HSP27 promotes vasculogenic mimicry formation in human salivary adenoid cystic carcinoma via the AKT-MMP-2/9 pathway

PURPOSE

To explore the role and mechanism of heat shock protein 27 (HSP27) in SACC VM formation.

STUDY DESIGN

Immunohistochemistry and double staining with cluster of differentiation 31 (CD31) and periodic acid-Schiff (PAS) were used to detect HSP27 expression and VM in 70 SACC tissue samples separately. Quantitative real-time polymerase chain reaction (qRT-PCR), western blot analysis, and immunofluorescence were used to detect gene and protein expression. HSP27 in SACC cells were overexpression or downregulated by transfecting HSP27 or short hairpin RNA target HSP27 (sh-HSP27). The migration and invasion abilities of SACC cells were detected using wound healing and Transwell invasion assays. The VM formation ability of the cells in vitro was detected using a Matrigel 3-dimensional culture.

RESULTS

HSP27 expression was positively correlated with VM formation and affected the prognosis of patients. In vitro, HSP27 upregulation engendered VM formation and the invasion and migration of SACC cells. Mechanistically, HSP27 upregulation increased Akt phosphorylation and subsequently increased downstream matrix metalloproteinase 2 and 9 expressions.

CONCLUSION

HSP27 may plays an important role in VM formation in SACC via the AKT-MMP-2/9 signalling pathway.

LIFU/MMP-2 dual-responsive release of repurposed drug disulfiram from nanodroplets for inhibiting vasculogenic mimicry and lung metastasis in triple-negative breast cancer

BACKGROUND

Vasculogenic mimicry (VM), when microvascular channels are formed by cancer cells independent of endothelial cells, often occurs in deep hypoxic areas of tumors and contributes to the aggressiveness and metastasis of triple-negative breast cancer (TNBC) cells. However, well-developed VM inhibitors exhibit inadequate efficacy due to their low drug utilization rate and limited deep penetration. Thus, a cost-effective VM inhibition strategy needs to be designed for TNBC treatment.

RESULTS

Herein, we designed a low-intensity focused ultrasound (LIFU) and matrix metalloproteinase-2 (MMP-2) dual-responsive nanoplatform termed PFP@PDM-PEG for the cost-effective and efficient utilization of the drug disulfiram (DSF) as a VM inhibitor. The PFP@PDM-PEG nanodroplets effectively penetrated tumors and exhibited substantial accumulation facilitated by PEG deshielding in a LIFU-mediated and MMP-2-sensitive manner. Furthermore, upon exposure to LIFU irradiation, DSF was released controllably under ultrasound imaging guidance. This secure and controllable dual-response DSF delivery platform reduced VM formation by inhibiting COL1/pro-MMP-2 activity, thereby significantly inhibiting tumor progression and metastasis.

CONCLUSIONS

Considering the safety of the raw materials, controlled treatment process, and reliable repurposing of DSF, this dual-responsive nanoplatform represents a novel and effective VM-based therapeutic strategy for TNBC in clinical settings.

Toward morphologically relevant extracellular matrix: nanofiber-hydrogel composites for tumor cell culture

The natural extracellular matrix (ECM) consists of a continuous integrated fibrin network and a negatively charged proteoglycan-based matrix. In this work, we report a novel three-dimensional nanofiber hydrogel composite that mimics the natural ECM structure, exhibiting both degradability and mechanical characteristics comparable to that of tumor tissue. The embedded nanofiber improves the hydrogel mechanical properties, and varying the fiber density can match the elastic modulus of different tumor tissues (1.51-10.77 kPa). The degradability of the scaffold gives sufficient space for tumor cells to secrete and remodel the ECM. The expression levels of cancer stem cell markers confirmed the development of aggressive and metastatic phenotypes of prostate cancer cells in the 3D scaffold. Similar results were obtained in terms of anticancer resistance of prostate cancer cells in 3D scaffolds showing stem cell-like properties, suggesting that the current bionic 3D scaffold tumor model has broad potential in the development of effective targeted agents.

Pan-cancer dissection of vasculogenic mimicry characteristic to provide potential therapeutic targets

Introduction

Vasculogenic mimicry (VM) represents a novel form of tumor angiogenesis that is associated with tumor invasiveness and drug resistance. However, the VM landscape across cancer types remains poorly understood. In this study, we elucidate the characterizations of VM across cancers based on multi-omics data and provide potential targeted therapeutic strategies.

Methods

Multi-omics data from The Cancer Genome Atlas was used to conduct comprehensive analyses of the characteristics of VM related genes (VRGs) across cancer types. Pan-cancer vasculogenic mimicry score was established to provide a depiction of the VM landscape across cancer types. The correlation between VM and cancer phenotypes was conducted to explore potential regulatory mechanisms of VM. We further systematically examined the relationship between VM and both tumor immunity and tumor microenvironment (TME). In addition, cell communication analysis based on single-cell transcriptome data was used to investigate the interactions between VM cells and TME. Finally, transcriptional and drug response data from the Genomics of Drug Sensitivity in Cancer database were utilized to identify potential therapeutic targets and drugs. The impact of VM on immunotherapy was also further clarified.

Results

Our study revealed that VRGs were dysregulated in tumor and regulated by multiple mechanisms. Then, VM level was found to be heterogeneous among different tumors and correlated with tumor invasiveness, metastatic potential, malignancy, and prognosis. VM was found to be strongly associated with epithelial-mesenchymal transition (EMT). Further analyses revealed cancer-associated fibroblasts can promote EMT and VM formation. Furthermore, the immune-suppressive state is associated with a microenvironment characterized by high levels of VM. VM score can be used as an indicator to predict the effect of immunotherapy. Finally, seven potential drugs targeting VM were identified.

Conclusion

In conclusion, we elucidate the characteristics and key regulatory mechanisms of VM across various cancer types, underscoring the pivotal role of CAFs in VM. VM was further found to be associated with the immunosuppressive TME. We also provide clues for the research of drugs targeting VM. Our study provides an initial overview and reference point for future research on VM, opening up new avenues for therapeutic intervention.

RUNX1-BMP2 promotes vasculogenic mimicry in laryngeal squamous cell carcinoma via activation of the PI3K-AKT signaling pathway

BACKGROUND

Laryngeal squamous cell carcinoma (LSCC) is one of the most common malignant tumors of the head and neck. Vasculogenic mimicry (VM) is crucial for tumor growth and metastasis and refers to the formation of fluid channels by invasive tumor cells rather than endothelial cells. However, the regulatory mechanisms underlying VM during the malignant progression of LSCC remain largely unknown.

METHODS

Gene expression and clinical data for LSCC were obtained from the TCGA and Gene GEO (GSE27020) databases. A risk prediction model associated with VM was established using LASSO and Cox regression analyses. Based on their risk scores, patients with LSCC were categorized into high- and low-risk groups. The disparities in immune infiltration, tumor mutational burden (TMB), and functional enrichment between these two groups were examined. The core genes in LSCC were identified using the machine learning (SVM-RFE) and WGCNA algorithms. Subsequently, the involvement of bone morphogenetic protein 2 (BMP2) in VM and metastasis was investigated both in vitro and in vivo. To elucidate the downstream signaling pathways regulated by BMP2, western blotting was performed. Additionally, ChIP experiments were employed to identify the key transcription factors responsible for modulating the expression of BMP2.

RESULTS

We established a new precise prognostic model for LSCC related to VM based on three genes: BMP2, EPO, and AGPS. The ROC curves from both TCGA and GSE27020 validation cohorts demonstrated precision survival prediction capabilities, with the nomogram showing some net clinical benefit. Multiple algorithm analyses indicated BMP2 as a potential core gene. Further experiments suggested that BMP2 promotes VM and metastasis in LSCC. The malignant progression of LSCC is promoted by BMP2 via the activation of the PI3K-AKT signaling pathway, with the high expression of BMP2 in LSCC resulting from its transcriptional activation by runt-related transcription factor 1 (RUNX1).

CONCLUSION

BMP2 predicts poor prognosis in LSCC, promotes LSCC VM and metastasis through the PI3K-AKT signaling pathway, and is transcriptionally regulated by RUNX1. BMP2 may be a novel, precise, diagnostic, and therapeutic biomarker of LSCC.

EHMT2 Suppresses ARRB1 Transcription and Activates the Hedgehog Signaling to Promote Malignant Phenotype and Stem Cell Property in Oral Squamous Cell Carcinoma

Oral squamous cell carcinoma (OSCC) represents the primary subtype of head and neck squamous cell carcinoma (HNSCC), characterized by a high morbidity and mortality rate. Although previous studies have established specific correlations between euchromatic histone lysine methyltransferase 2 (EHMT2), a histone lysine methyltransferase, and the malignant phenotype of OSCC cells, its biological functions in OSCC remain largely unknown. This study, grounded in bioinformatics predictions, aims to clarify the influence of EHMT2 on the malignant behavior of OSCC cells and delve into the underlying mechanisms. EHMT2 exhibited high expression in OSCC tissues and demonstrated an association with poor patient outcomes. Artificial EHMT2 silencing in OSCC cells, achieved through lentiviral vector infection, significantly inhibited colony formation, migration, invasion, and cell survival. Regarding the mechanism, EHMT2 was found to bind the promoter of arrestin beta 1 (ARRB1), thereby suppressing its transcription through H3K9me2 modification. ARRB1, in turn, was identified as a negative regulator of the Hedgehog pathway, leading to a reduction in the proteins GLI1 and PTCH1. Cancer stem cells (CSCs) were enriched through repeated sphere formation assays in two OSCC cell lines. EHMT2 was found to activate the Hedgehog pathway, thus promoting sphere formation, migration and invasion, survival, and tumorigenic activity of the OSCC-CSCs. Notably, these effects were counteracted by the additional overexpression of ARRB1. In conclusion, this study provides novel evidence suggesting that EHMT2 plays specific roles in enhancing stem cell properties in OSCC by modulating the ARRB1-Hedgehog signaling cascade.

Magnetic Particle Imaging: From Tracer Design to Biomedical Applications in Vasculature Abnormality

Magnetic particle imaging (MPI) is an emerging non-invasive tomographic technique based on the response of magnetic nanoparticles (MNPs) to oscillating drive fields at the center of a static magnetic gradient. In contrast to magnetic resonance imaging (MRI), which is driven by uniform magnetic fields and projects the anatomic information of the subjects, MPI directly tracks and quantifies MNPs in vivo without background signals. Moreover, it does not require radioactive tracers and has no limitations on imaging depth. This article first introduces the basic principles of MPI and important features of MNPs for imaging sensitivity, spatial resolution, and targeted biodistribution. The latest research aiming to optimize the performance of MPI tracers is reviewed based on their material composition, physical properties, and surface modifications. While the unique advantages of MPI have led to a series of promising biomedical applications, recent development of MPI in investigating vascular abnormalities in cardiovascular and cerebrovascular systems, and cancer are also discussed. Finally, recent progress and challenges in the clinical translation of MPI are discussed to provide possible directions for future research and development.

Tumor metabolic crosstalk and immunotherapy

Tumor cells must resist the host's immune system while maintaining growth under harsh conditions of acidity and hypoxia, which indicates that tumors are more robust than normal tissue. Immunotherapeutic agents have little effect on solid tumors, mostly because of the tumor density and the difficulty of penetrating deeply into the tissue to achieve the theoretical therapeutic effect. Various therapeutic strategies targeting the tumor microenvironment (TME) have been developed. Immunometabolic disorders play a dominant role in treatment resistance at both the TME and host levels. Understanding immunometabolic factors and their treatment potential may be a way forward for tumor immunotherapy. Here, we summarize the metabolism of substances that affect tumor progression, the crosstalk between the TME and immunosuppression, and some potential tumor-site targets. We also summarize the progress and challenges of tumor immunotherapy.

HIF-1α Mediates Immunosuppression and Chemoresistance in Colorectal Cancer by Inhibiting CXCL9, -10 and -11

Uncertainty exists regarding the mechanisms by which hypoxia-inducible factors (HIFs) control CD8+T-cell migration into tumor microenvironments. Here, we found that HIF-1α knockdown or overexpression resulted in increased or decreased CXCL9, -10, and -11 expression in vitro, respectively. Gene Set Variation Analysis revealed that elevated HIF-1α levels correlated with a poor prognosis, severe pathological stage, and an absence of CD8+ T cells in the tumor microenvironment in colorectal cancer (CRC) patients. HIF-1α was inversely associated with pathways beneficial to anti-tumor immunotherapy and cytokine/chemokine function. In vivo, inhibiting HIF-1α or its upstream regulator BIRC2 significantly suppressed tumor growth and promoted CD8+ T-cell infiltration. CXCR3 neutralizing antibodies reversed these effects, implicating the involvement of CXCL9, -10, and -11/CXCR3 axis. The presence of HIF-1α weakened the upregulation of CXCL9, -10, and -11 by bleomycin and doxorubicin. Combining HIF-1α inhibition with bleomycin promoted CD8+ T-cell infiltration and tumor suppression in vivo. Moreover, doxorubicin could upregulate CXCL9, -10 and -11 by suppressing HIF-1α. Our findings highlight the potential of HIF-1α inhibition to improve CRC microenvironments and increase chemotherapy sensitivity.

Inhibition of PD-L1 expression in non-small cell lung cancer may reduce vasculogenic mimicry formation by inhibiting the epithelial mesenchymal transformation process

Non-small cell lung cancer (NSCLC) is a kind of highly malignant tumor. Studies have shown that Vasculogenic mimicry (VM) may be responsible for dismal prognosis in NSCLC. Immunotherapy with programmed death-1 (PD-1) or programmed death ligand-1 (PD-L1) has significantly altered the treatment of assorted cancers, including NSCLC, but its role and mechanism in the formation of Vasculogenic mimicry (VM) in NSCLC remains unclear. This study aimed to investigate the role of the anti-PD-L1 antibody in the formation of VM in NSCLC and its possible mechanisms. The results showed that anti-PD-L1 antibody therapy could inhibit the growth of NSCLC-transplanted tumors and reduce the formation of VMs. In addition, this study found that anti-PD-L1 antibodies could increase the expression of the epithelial-mesenchymal transition (EMT) related factor E-cadherin. zinc finger E-box binding homeobox 1 (ZEB1) is an important transcription factor regulating EMT. Knocking down ZEB1 could significantly inhibit tumor growth, as well as the expression of VE-cadherin and mmp2, while remarkably increase the expression of E-cadherin. During this process, the formation of VM was inhibited by knowing down ZEB1 in both in vitro and in vivo experiments of the constructed ZEB1 knockdown stable transfected cell strains. Therefore, in this study, we found that anti-PD-L1 antibodies may reduce the formation of VMs by inhibiting the EMT process.

Theranostic Fluorescent Probes

The ability to gain spatiotemporal information, and in some cases achieve spatiotemporal control, in the context of drug delivery makes theranostic fluorescent probes an attractive and intensely investigated research topic. This interest is reflected in the steep rise in publications on the topic that have appeared over the past decade. Theranostic fluorescent probes, in their various incarnations, generally comprise a fluorophore linked to a masked drug, in which the drug is released as the result of certain stimuli, with both intrinsic and extrinsic stimuli being reported. This release is then signaled by the emergence of a fluorescent signal. Importantly, the use of appropriate fluorophores has enabled not only this emerging fluorescence as a spatiotemporal marker for drug delivery but also has provided modalities useful in photodynamic, photothermal, and sonodynamic therapeutic applications. In this review we highlight recent work on theranostic fluorescent probes with a particular focus on probes that are activated in tumor microenvironments. We also summarize efforts to develop probes for other applications, such as neurodegenerative diseases and antibacterials. This review celebrates the diversity of designs reported to date, from discrete small-molecule systems to nanomaterials. Our aim is to provide insights into the potential clinical impact of this still-emerging research direction.

Antibody-Drug Conjugate αEGFR-E-P125A Reduces Triple-negative Breast Cancer Vasculogenic Mimicry, Motility, and Metastasis through Inhibition of EGFR, Integrin, and FAK/STAT3 Signaling

Primary tumor growth and metastasis in triple-negative breast cancer (TNBC) require supporting vasculature, which develop through a combination of endothelial angiogenesis and vasculogenic mimicry (VM), a process associated with aggressive metastatic behavior in which vascular-like structures are lined by tumor cells. We developed αEGFR-E-P125A, an antibody-endostatin fusion protein that delivers a dimeric, mutant endostatin (E-P125A) payload that inhibits TNBC angiogenesis and VM in vitro and in vivo. To characterize the mechanisms associated with induction and inhibition of VM, RNA sequencing (RNA-seq) of MDA-MB-231-4175 TNBC cells grown in a monolayer (two-dimensional) was compared with cells plated on Matrigel undergoing VM [three-dimensional (3D)]. We then compared RNA-seq between TNBC cells in 3D and cells in 3D with VM inhibited by αEGFR-E-P125A (EGFR-E-P125A). Gene set enrichment analysis demonstrated that VM induction activated the IL6-JAK-STAT3 and angiogenesis pathways, which were downregulated by αEGFR-E-P125A treatment.Correlative analysis of the phosphoproteome demonstrated decreased EGFR phosphorylation at Y1069, along with decreased phosphorylation of focal adhesion kinase Y397 and STAT3 Y705 sites downstream of α5β1 integrin. Suppression of phosphorylation events downstream of EGFR and α5β1 integrin demonstrated that αEGFR-E-P125A interferes with ligand-receptor activation, inhibits VM, and overcomes oncogenic signaling associated with EGFR and α5β1 integrin cross-talk. In vivo, αEGFR-E-P125A treatment decreased primary tumor growth and VM, reduced lung metastasis, and confirmed the inhibition of signaling events observed in vitro. Simultaneous inhibition of EGFR and α5β1 integrin signaling by αEGFR-E-P125A is a promising strategy for the inhibition of VM, tumor growth, motility, and metastasis in TNBC and other EGFR-overexpressing tumors.

SIGNIFICANCE

αEGFR-E-P125A reduces VM, angiogenesis, tumor growth, and metastasis by inhibiting EGFR and α5β1 integrin signaling, and is a promising therapeutic agent for TNBC treatment, used alone or in combination with chemotherapy.

CD146+CAFs promote progression of endometrial cancer by inducing angiogenesis and vasculogenic mimicry via IL-10/JAK1/STAT3 pathway

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.

Application status and optimization suggestions of tumor organoids and CAR-T cell co-culture models

Tumor organoids, especially patient-derived organoids (PDOs) exhibit marked similarities in histopathological morphology, genomic alterations, and specific marker expression profiles to those of primary tumour tissues. They are applied in various fields including drug screening, gene editing, and identification of oncogenes. However, CAR-T therapy in the treatment of solid tumours is still at an exploratory stage. Tumour organoids offer unique advantages over other preclinical models commonly used for CAR-T therapy research, which the preservation of the biological characteristics of primary tumour tissue is critical for the study of early-stage solid tumour CAR-T therapies. Although some investigators have used this co-culture model to validate newly targeted CAR-T cells, optimise existing CAR-T cells and explore combination therapy strategies, there is still untapped potential in the co-culture models used today. This review introduces the current status of the application of tumour organoid and CAR-T cell co-culture models in recent years and commented on the limitations of the current co-cultivation model. Meanwhile, we compared the tumour organoid model with two pre-clinical models commonly used in CAR-T therapy research. Eventually, combined with the new progress of organoid technologies, optimization suggestions were proposed for the co-culture model from five perspectives: preserving or reconstructing the tumor microenvironment, systematization, vascularization, standardized culture procedures, and expanding the tumor organoids resource library, aimed at assisting related researchers to better utilize co-culture models.

A nano-platform combats the "attack" and "defense" of cytoskeleton to block cascading tumor metastasis

The cytoskeleton facilitates tumor cells invasion into the bloodstream via vasculogenic mimicry (VM) for "attack", and protects cells against external threats through cytoskeletal remodeling and tunneling nanotubes (TNTs) for "defense". However, the existing strategies involving cytoskeleton are not sufficient to eliminate tumor metastasis due to mitochondrial energy supply, both within tumor cells and from outside microenvironment. Here, considering the close relationship between cytoskeleton and mitochondria both in location and function, we construct a nano-platform that combats the "attack" and "defense" of cytoskeleton in the cascading metastasis. The nano-platform is composed of KFCsk@LIP and KTMito@LIP for the cytoskeletal collapse and mitochondrial dysfunction. KFCsk@LIP prevents the initiation and circulation of cascading tumor metastasis, but arouses limited suppression in tumor cell proliferation. KTMito@LIP impairs mitochondria to trigger apoptosis and impede energy supply both from inside and outside, leading to an amplified effect for metastasis suppression. Further mechanisms studies reveal that the formation of VM and TNTs are seriously obstructed. Both in situ and circulating tumor cells are disabled. Subsequently, the broken metastasis cascade results in a remarkable anti-metastasis effect. Collectively, based on the nano-platform, the cytoskeletal collapse with synchronous mitochondrial dysfunction provides a potential therapeutic strategy for cascading tumor metastasis suppression.

Current advances in modulating tumor hypoxia for enhanced therapeutic efficacy

Hypoxia is a common feature of most solid tumors, which promotes the proliferation, invasion, metastasis, and therapeutic resistance of tumors. Researchers have been developing advanced strategies and nanoplatforms to modulate tumor hypoxia to enhance therapeutic effects. A timely review of this rapidly developing research topic is therefore highly desirable. For this purpose, this review first introduces the impact of hypoxia on tumor development and therapeutic resistance in detail. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are also systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We provide a detailed discussion of the rationale and research progress of these strategies. Through a review of current trends, it is hoped that this comprehensive overview can provide new prospects for clinical application in tumor treatment. STATEMENT OF SIGNIFICANCE: As a common feature of most solid tumors, hypoxia significantly promotes tumor progression. Advanced nanoplatforms have been developed to modulate tumor hypoxia to enhanced therapeutic effects. In this review, we first introduce the impact of hypoxia on tumor progression. Current developments in the construction of various nanoplatforms to enhance tumor treatment in response to hypoxia are systematically summarized, including hypoxia-overcoming, hypoxia-exploiting, and hypoxia-disregarding strategies. We discuss the rationale and research progress of the above strategies in detail, and finally introduce future challenges for treatment of hypoxic tumors. By reviewing the current trends, this comprehensive overview can provide new prospects for clinical translatable tumor therapy.

Plasticity and resistance of cancer stem cells as a challenge for innovative anticancer therapies - do we know enough to overcome this?

According to the CSC hypothesis, cancer stem cells are pivotal in initiating, developing, and causing cancer recurrence. Since the identification of CSCs in leukemia, breast cancer, glioblastoma, and colorectal cancer in the 1990s, researchers have actively investigated the origin and biology of CSCs. However, the CSC hypothesis and the role of these cells in tumor development model is still in debate. These cells exhibit distinct surface markers, are capable of self-renewal, demonstrate unrestricted proliferation, and display metabolic adaptation. CSC phenotypic plasticity and the capacity to EMT is strictly connected to the stemness state. CSCs show high resistance to chemotherapy, radiotherapy, and immunotherapy. The plasticity of CSCs is significantly influenced by tumor microenvironment factors, such as hypoxia. Targeting the genetic and epigenetic changes of cancer cells, together with interactions with the tumor microenvironment, presents promising avenues for therapeutic strategies. See also the Graphical abstract(Fig. 1).

Establishment of skin cutaneous melanoma prognosis model based on vascular mimicry risk score

Studies have indicated that Vascular mimicry (VM) could contribute to the unfavorable prognosis of skin cutaneous melanoma (SKCM). Thus, the objective of this study was to identify therapeutic targets associated with VM in SKCM and develop a novel prognostic model. Gene expression data from The Cancer Genome Atlas (TCGA) and Genotype-Tissue Expression (GTEx) were utilized to identify differentially expressed genes (DEGs). By intersecting these DEGs with VM genes, we acquired VM-related DEGs specific to SKCM, and then identified prognostic-related VM genes. A VM risk score system was established based on these prognosis-associated VM genes, and patients were then categorized into high- and low-score groups using the median score. Subsequently, differences in clinical characteristics, gene set enrichment analysis (GSEA), and other analyses were further presented between the 2 groups of patients. Finally, a novel prognostic model for SKCM was established using the VM score and clinical characteristics. 26 VM-related DEGs were identified in SKCM, among the identified DEGs associated with VM in SKCM, 5 genes were found to be prognostic-related. The VM risk score system, comprised of these genes, is an independent prognostic risk factor. There were significant differences between the 2 patient groups in terms of age, pathological stage, and T stage. VM risk scores are associated with epithelial biological processes, angiogenesis, regulation of the SKCM immune microenvironment, and sensitivity to targeted drugs. The novel prognostic model demonstrates excellent predictive ability. Our study identified VM-related prognostic markers and therapeutic targets for SKCM, providing novel insights for clinical diagnosis and treatment.

Global trends in tumor microenvironment-related research on tumor vaccine: a review and bibliometric analysis

Background

Tumor vaccines have become crucial in cancer immunotherapy, but, only a limited number of phase III clinical trials have demonstrated clinical efficacy. The crux of this issue is the inability of tumor vaccines to effectively harmonize the tumor microenvironment with its intricate interplay. One factor that can hinder the effectiveness of vaccines is the natural immunosuppressive element present in the tumor microenvironment. This element can lead to low rates of T-cell response specific to antigens and the development of acquired resistance. Conversely, anticancer vaccines alter the tumor microenvironment in conflicting manners, inducing both immune activation and immunological evasion. Hence, comprehending the correlation between tumor vaccines and the tumor microenvironment would establish a foundation for forthcoming tumor treatment.

Objective

Our review explores the realm of research pertaining to tumor vaccinations and the tumor microenvironment. Our objective is to investigate the correlation between tumor vaccines and the tumor microenvironment within this domain. We then focus our review on the dominant international paradigms in this research field and visually illustrates the historical progression and emergent patterns observed in the past.

Methods

From January 1, 1999 to February 7, 2023, 1420 articles on the interplay between tumor vaccines and the tumor microenvironment were published, according to The Clarivate Web of Science (WOS) database used in our review. A bibliometric review was designed for this collection and consisted of an evaluation. The evaluation encompassed various discernible attributes, including the year of publication, the journals in which the articles were published, the authors involved, the affiliated institutions, the geographical locations of the institutions, the references cited, and the keywords employed.

Results

Between the years 1999 and 2022, publications saw a significant increase, from 3 to 265 annually. With 72 papers published, Frontiers in Immunology had the most manuscripts published. The Cancer Research publication garnered the highest number of citations, amounting to 2874 citations. The United States exerts significant dominance in the subject, with the National Cancer Institute being recognized as a prominent institution in terms of both productivity and influence. Furthermore, Elizabeth M. Jaffee was recognized as the field's most prolific and influential author with 24 publications and 1,756 citations. The co-occurrence cluster analysis was conducted on the top 197 keywords, resulting in the identification of five distinct clusters. The most recent high-frequency keywords, namely immune therapy, dendritic cell, tumor microenvironment, cancer, and vaccine, signify the emerging frontiers in the interaction between tumor vaccines and the tumor microenvironment.

Conclusion

Our review uncovers insights into contemporary trends, global patterns of collaboration, fundamental knowledge, research areas of high interest, and emerging frontiers in the field of TME-targeted vaccines.