FoxO1 transcriptional activities in VEGF expression and beyond: a key regulator in functional angiogenesis?

tgfβ1a/vegfa gene expression and methylation in response to acute hypoxia in Japanese flounder (Paralichthys olivaceus)

The physiological response and molecular mechanism of the immune response of Japanese flounder under hypoxia stress remain unclear. In this study, we examined the immune-related physiological indexes and the molecular mechanisms of Japanese flounders under acute hypoxia stress. The results showed that the levels of serum ALT, ALP, AST and LDH in hypoxia stress group were significantly increased (P < 0.01). Through quantitative real-time PCR and double in situ hybridization, we found acute hypoxia stress induced immune response of skeletal muscle and gill filaments. The transcriptional regulation mechanism of this immune signaling pathway was investigated by dual luciferase assay. In addition, DNA methylation levels of genes were detected to explore epigenetic modifications of this pathway. As a transcription factor, Foxo1a can interact tgfβ1a(AGATGTTTTTT) and vegfa(TTCTTTTTATA, TACTGTTGCTA) sequences of the promoter regions. The DNA methylation levels of tgfβ1a and vegfa genes were significantly affected by hypoxia and negatively correlated with their expression. These experiments showed that the expression of immune related genes tgfβ1a and vegfa were regulated by transcription factor Foxo1a and DNA methylation. Our study provides theoretical foundations for acute hypoxia stress induced immune response of Japanese flounder.

Research progress on the mechanism of angiogenesis in wound repair and regeneration

Poor wound healing and pathological healing have been pressing issues in recent years, as they impact human quality of life and pose risks of long-term complications. The study of neovascularization has emerged as a prominent research focus to address these problems. During the process of repair and regeneration, the establishment of a new vascular system is an indispensable stage for complete healing. It provides favorable conditions for nutrient delivery, oxygen supply, and creates an inflammatory environment. Moreover, it is a key manifestation of the proliferative phase of wound healing, bridging the inflammatory and remodeling phases. These three stages are closely interconnected and inseparable. This paper comprehensively integrates the regulatory mechanisms of new blood vessel formation in wound healing, focusing on the proliferation and migration of endothelial cells and the release of angiogenesis-related factors under different healing outcomes. Additionally, the hidden link between the inflammatory environment and angiogenesis in wound healing is explored.

Cancer-associated fibroblasts derived extracellular vesicles promote angiogenesis of colorectal adenocarcinoma cells through miR-135b-5p/FOXO1 axis

Colorectal adenocarcinoma (COAD) is a prevalent malignant tumor. Cancer-associated fibroblasts (CAFs)-derived extracellular vesicles (EVs) (CAFs-EVs) are implicated in COAD treatment. This study explored the mechanism of CAFs-EVs in COAD. CAFs and normal fibroblast (NFs) were isolated from COAD tissues and adjacent normal tissues. Vimentin, α-SMA, and FAP expressions were detected. EVs were isolated from CAFs and identified. SW480 and HCT116 cells were co-incubated with EVs. The EV uptake and COAD cell malignant behaviors were assessed. EV-treated SW480 and HCT116 cells were co-cultured with human umbilical vein endothelial cells (HUVECs). Extensive analyses were conducted to examine HUVEC proliferation, migration, and angiogenesis, and miR-135b-5p expression in COAD cells, and SW480 and HCT116 cells. CAFs were transfected with the miR-135b-5p inhibitor. miR-135b-5p downstream targets were predicted. FOXO1 expression in the co-culture system was determined and then overexpressed to evaluate its role in HUVECs mediated by COAD cells. COAD mouse model was established by transplanting SW480 cells into nude mice and injecting with EVs. Tumor growth rate, volume, and weight were examined. Ki67, VEGF, CD34, FOXO1 expressions, and VEGF content were detected. CAFs-EVs promoted COAD cell malignant behaviors and COAD cells-mediated HUVEC proliferation, migration, and angiogenesis. CAFs-EVs delivered miR-135b-5p into COAD cells. miR-135b-5p targeted FOXO1. Inhibition of miR-135b-5p in EVs or overexpression of FOXO1 partially reversed the effect of EVs on promoting COAD-induced angiogenesis. CAFs-EVs promoted tumor proliferation and angiogenesis of COAD in vivo. CAFs-EVs delivered miR-135b-5p into COAD cells to downregulate FOXO1 and promote HUVECs proliferation, migration, and angiogenesis.

SIRT1/FOXO1 Axis-Mediated Hippocampal Angiogenesis is Involved in the Antidepressant Effect of Chaihu Shugan San

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Development of an arteriolar niche and self-renewal of breast cancer stem cells by lysophosphatidic acid/protein kinase D signaling

Breast cancer stem cells (BCSCs) are essential for cancer growth, metastasis and recurrence. The regulatory mechanisms of BCSC interactions with the vascular niche within the tumor microenvironment (TME) and their self-renewal are currently under extensive investigation. We have demonstrated the existence of an arteriolar niche in the TME of human BC tissues. Intriguingly, BCSCs tend to be enriched within the arteriolar niche in human estrogen receptor positive (ER+) BC and bi-directionally interact with arteriolar endothelial cells (ECs). Mechanistically, this interaction is driven by the lysophosphatidic acid (LPA)/protein kinase D (PKD-1) signaling pathway, which promotes both arteriolar differentiation of ECs and self-renewal of CSCs likely via differential regulation of CD36 transcription. This study indicates that CSCs may enjoy blood perfusion to maintain their stemness features. Targeting the LPA/PKD-1 -CD36 signaling pathway may have therapeutic potential to curb tumor progression by disrupting the arteriolar niche and effectively eliminating CSCs.

Notch Signaling in Vascular Endothelial Cells, Angiogenesis, and Tumor Progression: An Update and Prospective

The Notch signaling pathway plays an essential role in a wide variety of biological processes including cell fate determination of vascular endothelial cells and the regulation of arterial differentiation and angiogenesis. The Notch pathway is also an essential regulator of tumor growth and survival by functioning as either an oncogene or a tumor suppressor in a context-dependent manner. Crosstalk between the Notch and other signaling pathways is also pivotal in tumor progression by promoting cancer cell growth, migration, invasion, metastasis, tumor angiogenesis, and the expansion of cancer stem cells (CSCs). In this review, we provide an overview and update of Notch signaling in endothelial cell fate determination and functioning, angiogenesis, and tumor progression, particularly in the development of CSCs and therapeutic resistance. We further summarize recent studies on how endothelial signaling crosstalk with the Notch pathway contributes to tumor angiogenesis and the development of CSCs, thereby providing insights into vascular biology within the tumor microenvironment and tumor progression.

Heterogeneity of Vascular Endothelial Cells, De Novo Arteriogenesis and Therapeutic Implications in Pancreatic Neuroendocrine Tumors

Arteriogenesis supplies oxygen and nutrients in the tumor microenvironment (TME), which may play an important role in tumor growth and metastasis. Pancreatic neuroendocrine tumors (pNETs) are the second most common pancreatic malignancy and are frequently metastatic on presentation. Nearly a third of pNETs secrete bioactive substances causing debilitating symptoms. Current treatment options for metastatic pNETs are limited. Importantly, these tumors are highly vascularized and heterogeneous neoplasms, in which the heterogeneity of vascular endothelial cells (ECs) and de novo arteriogenesis may be critical for their progression. Current anti-angiogenetic targeted treatments have not shown substantial clinical benefits, and they are poorly tolerated. This review article describes EC heterogeneity and heterogeneous tumor-associated ECs (TAECs) in the TME and emphasizes the concept of de novo arteriogenesis in the TME. The authors also emphasize the challenges of current antiangiogenic therapy in pNETs and discuss the potential of tumor arteriogenesis as a novel therapeutic target. Finally, the authors prospect the clinical potential of targeting the FoxO1-CD36-Notch pathway that is associated with both pNET progression and arteriogenesis and provide insights into the clinical implications of targeting plasticity of cancer stem cells (CSCs) and vascular niche, particularly the arteriolar niche within the TME in pNETs, which will also provide insights into other types of cancer, including breast cancer, lung cancer, and malignant melanoma.

Punicalagin attenuates endothelial dysfunction by activating FoxO1, a pivotal regulating switch of mitochondrial biogenesis

Accumulating evidence has elucidated that hyperlipidemia is closely associated with an increasing prevalence of CVDs (cardiovascular diseases) because of endothelial dysfunction. In the present study, we investigated the effect and mechanism of PU (Punicalagin), a major ellagitannin in pomegranate, on endothelial dysfunction both in vivo and in vitro. In vivo, PU significantly ameliorated hyperlipidemia-induced accumulation of serum triglyceride and cholesterol as well as endothelial and mitochondrial dysfunction of thoracic aorta. Intriguingly, the FoxO1 (forkhead box O1) pathway was activated, which may account for prevention of vascular dysfunction and mitochondrial loss via upregulating mitochondrial biogenesis. In line, through in vitro cell cultures, our study demonstrated that PU not only increased the total FoxO1 protein, but also enhanced its nuclear translocation. In addition, silencing of FoxO1 remarkably abolished the ability of PU to augment the mitochondrial biogenesis, eNOS (endothelial NO synthase) expression, and oxidative stress, implying the irreplaceable role of FoxO1 in regulating endothelial function in the presence of PU. Conversely, suppression of excessive ROS (reactive oxygen species) secured the PA (palmitate)-induced decrease of FoxO1 expression, implying that there was a cross-talk between FoxO1 pathway and ROS. Concomitantly, the inflammatory response in current study was primarily mediated via p38 MAPK/NF-κB signaling pathway besides of FoxO1 pathway. Taken together, our findings suggest that PU ameliorates endothelial dysfunction by activating FoxO1 pathway, a pivotal regulating switch of mitochondrial biogenesis.