TGF-β1 promotes human breast cancer angiogenesis and malignant behavior by regulating endothelial-mesenchymal transition

Molecular mechanisms of endothelial-mesenchymal transition and its pathophysiological feature in cerebrovascular disease

The phenomenon of endothelial-mesenchymal transition (EndMT), a distinct subtype of epithelial-mesenchymal transition (EMT), has garnered significant attention from scholars. EndMT refers to the process whereby endothelial cells (ECs) transform into mesenchymal cells in response to various stimuli, resulting in the loss of their original characteristics. This process has diverse implications in both physiological and pathological states. Under physiological conditions, EndMT plays a crucial role in the development of the cardiovascular system. Conversely, under pathological conditions, EndMT has been identified as a pivotal factor in the development of cardiovascular diseases. Nonetheless, a comprehensive overview of EndMT in cerebrovascular disease is currently lacking. Here, we discuss the heterogeneity of EndMT occurrence and the regulatory factors involved in its development and analyze the feasibility of EndMT as a therapeutic target, aiming to provide a solid theoretical foundation and evidence to address diseases caused by pathological EndMT.

Angiogenesis: Biological Mechanisms and In Vitro Models

The translation of biomedical devices and drug research is an expensive and long process with a low probability of receiving FDA approval. Developing physiologically relevant in vitro models with human cells offers a solution to not only improving the odds of FDA approval but also to expand our ability to study complex in vivo systems in a simpler fashion. Animal models remain the standard for pre-clinical testing; however, the data from animal models is an unreliable extrapolation when anticipating a human response in clinical trials, thus contributing to the low rates of translation. In this review, we focus on in vitro vascular or angiogenic models because of the incremental role that the vascular system plays in the translation of biomedical research. The first section of this review discusses the most common angiogenic cytokines that are used in vitro to initiate angiogenesis, followed by angiogenic inhibitors where both initiators and inhibitors work to maintain vascular homeostasis. Next, we evaluate previously published in vitro models, where we evaluate capturing the physical environment for biomimetic in vitro modeling. These topics provide a foundation of parameters that must be considered to improve and achieve vascular biomimicry. Finally, we summarize these topics to suggest a path forward with the goal of engineering human in vitro models that emulate the in vivo environment and provide a platform for biomedical device and drug screening that produces data to support clinical translation.

Role of Xuefu Zhuyu decoction in improving pulmonary vascular remodeling by inhibiting endothelial-to-mesenchymal transition

BACKGROUND

Pulmonary hypertension (PH) is a serious vascular disease characterized by pulmonary vascular remodeling. Xuefu Zhuyu decoction (XFZYD) can potentially improve pulmonary vascular remodeling; however, its mechanism requires further investigation.

METHODS

Rat models of monocrotaline (MCT)-induced PH and chronic thromboembolic pulmonary hypertension (CTEPH) were employed to investigate whether XFZYD has the potential to improve pulmonary vascular remodeling. After 21 days of XFZYD administration, the right ventricular systolic pressure (RVSP), organ indices, and wall thickness of pulmonary arteries of the rats were measured. Considering the possibility of endothelial-to-mesenchymal transition (EndMT), the specific mechanism of XFZYD in improving pulmonary vascular remodeling was further explored. Immunofluorescence, immunohistochemistry, and western blotting were used to detect the expression of EndMT markers, transforming growth factor-β1 (TGF-β1)/Smad pathway-related proteins, hypoxia-inducible factor-1α (HIF-1α), and levels of reactive oxygen species (ROS) in the lung tissues.

RESULTS

XFZYD demonstrated significant efficacy in treating PH, as evidenced by its effects in both the rat models of MCT-induced PH and CTEPH. XFZYD remarkably improved pulmonary vascular remodeling while reducing RVSP and right ventricular hypertrophy. XFZYD has the potential to improve pulmonary vascular remodeling by inhibiting EndMT in the pulmonary vasculature. The underlying mechanism may be closely associated with the inhibition of TGF-β1/Smad and HIF-1α signaling pathways and the reduction of ROS levels in lung tissue by XFZYD.

CONCLUSION

This study indicates that XFZYD may inhibit EndMT by modulating the ROS/HIF-1α/TGF-β1 signaling pathway, thereby improving pulmonary vascular remodeling. These findings provide a theoretical foundation for the clinical application of XFZYD in PH.

A possible role of plasmin-dependent activation of TGF-β in cancer-associated thrombosis: Implications for therapy

While the prevalence of cancer-associated thrombosis (CAT) is high in cancer patients, its molecular mechanisms have not been fully elucidated. Moreover, the risks of recurrent CAT events and mortality remain high in cancer patients despite the introduction of anticoagulant/antiplatelet therapy. Here, we discuss the possibility that increased plasmin activity driven by anticoagulant/antiplatelet treatment might be the major mechanism responsible for the activation of an excess of cancer-derived transforming growth factor-beta (TGF-β) originating from cancer cells and the tumour microenvironment. Hence, high coagulation and fibrinolysis rates in cancer patients may be linked to high rates of TGF-β activation, especially the excess of TGF-β derived from cancer cells. In turn, high TGF-β activation could contribute directly to maintaining high thrombotic risk and CAT recurrence in cancer patients since TGF-β signalling increases gene expression and secretion of the fibrinolysis inhibitor plasminogen activator inhibitor 1 (PAI1). Thus, TGF-β could directly contribute to the high number of deaths among patients with cancer experiencing CAT, despite anticoagulant/antiplatelet treatment. In a longer-term perspective, increased TGF-β activation, by supporting a pro-coagulant cancer microenvironment, might also accelerate cancer progression. This review aims to discuss the published evidence that might support the scenario described above, and to put forward the hypothesis that cancer patients experiencing CAT events would largely benefit from anti-TGF-β therapy.

Single-cell transcriptional atlas of tumor-associated macrophages in breast cancer

BACKGROUND

The internal heterogeneity of breast cancer, notably the tumor microenvironment (TME) consisting of malignant and non-malignant cells, has been extensively explored in recent years. The cells in this complex cellular ecosystem activate or suppress tumor immunity through phenotypic changes, secretion of metabolites and cell-cell communication networks. Macrophages, as the most abundant immune cells within the TME, are recruited by malignant cells and undergo phenotypic remodeling. Tumor-associated macrophages (TAMs) exhibit a variety of subtypes and functions, playing significant roles in impacting tumor immunity. However, their precise subtype delineation and specific function remain inadequately defined.

METHODS

The publicly available single-cell transcriptomes of 49,141 cells from eight breast cancer patients with different molecular subtypes and stages were incorporated into our study. Unsupervised clustering and manual cell annotation were employed to accurately classify TAM subtypes. We then conducted functional analysis and constructed a developmental trajectory for TAM subtypes. Subsequently, the roles of TAM subtypes in cell-cell communication networks within the TME were explored using endothelial cells (ECs) and T cells as key nodes. Finally, analyses were repeated in another independent publish scRNA datasets to validate our findings for TAM characterization.

RESULTS

TAMs are accurately classified into 7 subtypes, displaying anti-tumor or pro-tumor roles. For the first time, we identified a new TAM subtype capable of proliferation and expansion in breast cancer-TUBA1B+ TAMs playing a crucial role in TAMs diversity and tumor progression. The developmental trajectory illustrates how TAMs are remodeled within the TME and undergo phenotypic and functional changes, with TUBA1B+ TAMs at the initial point. Notably, the predominant TAM subtypes varied across different molecular subtypes and stages of breast cancer. Additionally, our research on cell-cell communication networks shows that TAMs exert effects by directly modulating intrinsic immunity, indirectly regulating adaptive immunity through T cells, as well as influencing tumor angiogenesis and lymphangiogenesis through ECs.

CONCLUSIONS

Our study establishes a precise single-cell atlas of breast cancer TAMs, shedding light on their multifaceted roles in tumor biology and providing resources for targeting TAMs in breast cancer immunotherapy.

Research progress in tumor angiogenesis and drug resistance in breast cancer

Angiogenesis is considered a hallmark pathophysiological process in tumor development. Aberrant vasculature resulting from tumor angiogenesis plays a critical role in the development of resistance to breast cancer treatments, via exacerbation of tumor hypoxia, decreased effective drug concentrations within tumors, and immune-related mechanisms. Antiangiogenic therapy can counteract these breast cancer resistance factors by promoting tumor vascular normalization. The combination of antiangiogenic therapy with chemotherapy, targeted therapy, or immunotherapy has emerged as a promising approach for overcoming drug resistance in breast cancer. This review examines the mechanisms associated with angiogenesis and the interactions among tumor angiogenesis, the hypoxic tumor microenvironment, drug distribution, and immune mechanisms in breast cancer. Furthermore, this review provides a comprehensive summary of specific antiangiogenic drugs, and relevant studies assessing the reversal of drug resistance in breast cancer. The potential mechanisms underlying these interventions are discussed, and prospects for the clinical application of antiangiogenic therapy to overcome breast cancer treatment resistance are highlighted.

Role and recent progress of P2Y12 receptor in cancer development

P2Y12 receptor (P2Y12R) is an adenosine-activated G protein-coupled receptor (GPCR) that plays a central role in platelet function, hemostasis, and thrombosis. P2Y12R activation can promote platelet aggregation and adhesion to cancer cells, promote tumor angiogenesis, and affect the tumor immune microenvironment (TIME) and tumor drug resistance, which is conducive to the progression of cancers. Meanwhile, P2Y12R inhibitors can inhibit this effect, suggesting that P2Y12R may be a potential therapeutic target for cancer. P2Y12R is involved in cancer development and metastasis, while P2Y12R inhibitors are effective in inhibiting cancer. However, a new study suggests that long-term use of P2Y12R inhibitors may increase the risk of cancer and the mechanism remains to be explored. In this paper, we reviewed the structural and functional characteristics of P2Y12R and its role in cancer. We explored the role of P2Y12R inhibitors in different tumors and the latest advances by summarizing the basic and clinical studies on the effects of P2Y12R inhibitors on tumors.

Nudifloside, a Secoiridoid Glucoside Derived from Callicarpa nudiflora, Inhibits Endothelial-to-Mesenchymal Transition and Angiogenesis in Endothelial Cells by Suppressing Ezrin Phosphorylation

Callicarpa nudiflora is a traditional folk medicine in China used for eliminating stasis to subdue swelling. Several compounds from Callicarpa nudiflora have been proved to show anti-inflammatory, haemostasis, hepatitis, and anti-proliferative effects. Tumor endothelial cells play crucial roles in tumor-induced angiogenesis. Recently, it was demonstrated that ECs may be the important source of cancer associated fibroblasts (CAFs) through endothelial to mesenchymal transition (EndoMT). In this study, we evaluated the effects of nudifloside (NDF), a secoiridoid glucoside from Callicarpa Nudiflora, on TGF-β1-induced EndoMT and VEGF-induced angiogenesis, and the underlying mechanisms were also involved. It was found that NDF significantly inhibited enhanced migration, invasion and F-actin assembly in endothelial cells (ECs) exposed in TGF-β1. NDF obviously reversed expression of several biomarkers associated with EndoMT and recovered the morphological characteristics of ECs and tube-like structure induced by TGF-β1. Furthermore, treatment of NDF resulted in a significant destruction of VEGF-induced angiogenesis in vitro and ex vivo. Data from co-immunoprecipitation assay provided the evidence that Ezrin phosphorylation and the interaction with binding protein can be inhibited by NDF, which can be confirmed by data from Ezrin silencing assay. Collectively, the application of NDF inhibited TGF-β1-induced EndoMT and VEGF-induced angiogenesis in ECs by reducing Ezrin phosphorylation.

Multifaceted TGF-β signaling, a master regulator: From bench-to-bedside, intricacies, and complexities

Physiological embryogenesis and adult tissue homeostasis are regulated by transforming growth factor-β (TGF-β), an evolutionarily conserved family of secreted polypeptide factors, acting in an autocrine and paracrine manner. The role of TGF-β in inflammation, fibrosis, and cancer is complex and sometimes even contradictory, exhibiting either inhibitory or promoting effects depending on the stage of the disease. Under pathological conditions, especially fibrosis and cancer, overexpressed TGF-β causes extracellular matrix deposition, epithelial-mesenchymal transition, cancer-associated fibroblast formation, and/or angiogenesis. In this review article, we have tried to dive deep into the mechanism of action of TGF-β in inflammation, fibrosis, and carcinogenesis. As TGF-β and its downstream signaling mechanism are implicated in fibrosis and carcinogenesis blocking this signaling mechanism appears to be a promising avenue. However, targeting TGF-β carries substantial risk as this pathway is implicated in multiple homeostatic processes and is also known to have tumor-suppressor functions. There is a need for careful dosing of TGF-β drugs for therapeutic use and patient selection.

Rimonabant and Cannabidiol Rewrite the Interactions between Breast Cancer Cells and Tumor Microenvironment

The spread of breast cancer to distant sites is the major cause of death in breast cancer patients. Increasing evidence supports the role of the tumor microenvironment (TME) in breast cancers, and its pathologic assessment has become a diagnostic and therapeutic tool. In the TME, a bidirectional interplay between tumor and stromal cells occurs, both at the primary and metastatic site. Hundreds of molecules, including cytokines, chemokines, and growth factors, contribute to this fine interaction to promote tumor spreading. Here, we investigated the effects of Rimonabant and Cannabidiol, known for their antitumor activity, on reprogramming the breast TME. Both compounds directly affect the activity of several pathways involved in breast cancer progression. To mimic tumor-stroma interactions during breast-to-lung metastasis, we investigated the effect of the compounds on growth factor secretion from metastatic breast cancer cells and normal and activated lung fibroblasts. In this setting, we demonstrated the anti-metastatic potential of the two compounds, and the membrane array analyses highlighted their ability to alter the release of factors involved in the autocrine and paracrine regulation of tumor proliferation, angiogenesis, and immune reprogramming. The results enforce the antitumor potential of Rimonabant and Cannabidiol, providing a novel potential tool for breast cancer TME management.

New advances in the research of clinical treatment and novel anticancer agents in tumor angiogenesis

In 1971, Folkman proposed that tumors could be limited to very small sizes by blocking angiogenesis. Angiogenesis is the generation of new blood vessels from pre-existing vessels, considered to be one of the important processes in tumor growth and metastasis. Angiogenesis is a complex process regulated by various factors and involves many secreted factors and signaling pathways. Angiogenesis is important in the transport of oxygen and nutrients to the tumor during tumor development. Therefore, inhibition of angiogenesis has become an important strategy in the clinical management of many solid tumors. Combination therapies of angiogenesis inhibitors with radiotherapy and chemotherapy are often used in clinical practice. In this article, we will review common targets against angiogenesis, the most common and up-to-date anti-angiogenic drugs and clinical treatments in recent years, including active ingredients from chemical and herbal medicines.