靶向肿瘤血管生成的天然产物研究进展

血管生成在肿瘤的发生发展过程中起着非常重要的作用。促血管生成因子及其受体可以通过调节血管生成促进肿瘤发生发展。因此,发现和开发靶向血管生成因子药物已经成为治疗肿瘤的重要策略。近年来,天然产物因其结构多样、毒副作用低及作用机制独特等优势已然成为开发抗肿瘤药物的主要来源。本文归纳阐述了近年来靶向血管生成因子具有抗肿瘤活性的天然产物研究进展,为进一步发现和开发靶向肿瘤血管生成的天然药物提供重要的理论依据。     

SHED aggregate exosomes shuttled miR‐26a promote angiogenesis in pulp regeneration via TGF‐β/SMAD2/3 signalling

ObjectivesPulp regeneration brings big challenges for clinicians, and vascularization is considered as its determining factor. We previously accomplished pulp regeneration with autologous stem cells from deciduous teeth (SHED) aggregates implantation in teenager patients, however, the underlying mechanism needs to be clarified for regenerating pulp in adults. Serving as an important effector of mesenchymal stem cells (MSCs), exosomes have been reported to promote angiogenesis and tissue regeneration effectively. Here, we aimed to investigate the role of SHED aggregate‐derived exosomes (SA‐Exo) in the angiogenesis of pulp regeneration.Materials and MethodsWe extracted exosomes from SHED aggregates and utilized them in the pulp regeneration animal model. The pro‐angiogenetic effects of SA‐Exo on SHED and human umbilical vein endothelial cells (HUVECs) were evaluated. The related mechanisms were further investigated.ResultsWe firstly found that SA‐Exo significantly improved pulp tissue regeneration and angiogenesis in vivo. Next, we found that SA‐Exo promoted SHED endothelial differentiation and enhanced the angiogenic ability of HUVECs, as indicated by the in vitro tube formation assay. Mechanistically, miR‐26a, which is enriched in SA‐Exo, improved angiogenesis both in SHED and HUVECs via regulating TGF‐β/SMAD2/3 signalling.ConclusionsIn summary, these data reveal that SA‐Exo shuttled miR‐26a promotes angiogenesis via TGF‐β/SMAD2/3 signalling contributing to SHED aggregate‐based pulp tissue regeneration. These novel insights into SA‐Exo may facilitate the development of new strategies for pulp regeneration.     

不同介入时间和不同疗程高压氧治疗对脑出血模型大鼠动物学行为及促血管新生因子表达的影响

摘要 目的：探讨不同介入时间和不同疗程高压氧治疗对脑出血大鼠动物学行为及促血管新生因子表达的影响。方法：240只SD大鼠随机分为假手术组、脑出血组、高压氧组,每组各80只。采用胶原酶诱导建立脑出血大鼠模型,建模成功后根据高压氧介入时间分为6 h介入组、1 d介入组、2 d介入组、3 d介入组等亚组。分别治疗1周、2周、3周、4周,采用Longa评分法、平衡木评分法、Berderson评分法评估大鼠动物学行为,采用qRT-PCR检测大鼠脑组织血管内皮生长因子（VEGF）、缺氧诱导因子-1α（HIF-1α）mRNA表达。结果：不同介入时间、不同疗程,脑出血组、高压氧组脑出血大鼠动物学行为评分、脑组织VEGF mRNA与HIF-1α mRNA表达均高于假手术组（P<0.05）。治疗1周、2周、3周、4周,不同介入时间高压氧组脑出血大鼠动物学行为评分低于脑出血组,脑组织VEGF mRNA、HIF-1α mRNA表达高于脑出血组（P<0.05）。高压氧介入时间越早,治疗疗程越长,脑出血大鼠动物学行为评分越低,脑组织VEGF mRNA、HIF-1α mRNA表达越高,差异均有统计学意义（P<0.05）。结论：高压氧治疗能够改善脑出血大鼠动物学行为、促进促血管新生因子表达,且以脑出血后6 h介入、疗程4周效果最佳。     

Epigenetic down-regulation of microRNA-126 in scleroderma endothelial cells is associated with impaired responses to VEGF and defective angiogenesis

Impaired angiogenesis in scleroderma (SSc) is a critical component of SSc pathology. MicroRNA-126 (miR-126) is expressed in endothelial cells (MVECs) where it regulates VEGF responses by repressing the negative regulators of VEGF, including the sprouty-related protein-1 (SPRED1), and phosphoinositide-3 kinase regulatory subunit 2 (PIK3R2). MVECs were isolated from SSc skin and matched subjects (n = 6). MiR-126 expression was measured by qPCR and in situ hybridization. Matrigel-based tube assembly was used to test angiogenesis. MiR-126 expression was inhibited by hsa-miR-126 inhibitor and enhanced by hsa-miR-126 Mimic. Epigenetic regulation of miR-126 expression was examined by the addition of epigenetic inhibitors (Aza and TSA) to MVECs and by bisulphite genomic sequencing of DNA methylation of the miR-126 promoter region. MiR-126 expression, as well as EGFL7 (miR-126 host gene), in SSc-MVECs and skin, was significantly down-regulated in association with increased expression of SPRED1 and PIK3R2 and diminished response to VEGF. Inhibition of miR-126 in NL-MVECs resulted in reduced angiogenic capacity, whereas overexpression of miR-126 in SSc-MVECs resulted in enhanced tube assembly. Addition of Aza and TSA normalized miR-126 and EGFL7 expression levels in SSc-MVECs. Heavy methylation in miR-126/EGFL7 gene was noted. In conclusion, these results demonstrate that the down-regulation of miR-126 results in impaired VEGF responses.     

Baicalein alleviates osteoarthritis by protecting subchondral bone,inhibiting angiogenesis and synovial proliferation

Osteoarthritis (OA) is one of the most frequent chronic joint diseases with the increasing life expectancy. The main characteristics of the disease are loss of articular cartilage, subchondral bone sclerosis and synovium inflammation. Physical measures, drug therapy and surgery are the mainstay of treatments for OA, whereas drug therapies are mainly limited to analgesics, glucocorticoids, hyaluronic acids and some alternative therapies because of single therapeutic target of OA joints. Baicalein, a traditional Chinese medicine extracted from Scutellaria baicalensis Georgi, has been widely used in anti-inflammatory therapies. Previous studies revealed that baicalein could alleviate cartilage degeneration effectively by acting on articular chondrocytes. However, the mechanisms involved in baicalein-mediated protection of the OA are not completely understood in consideration of integrality of arthrosis. In this study, we found that intra-articular injection of baicalein ameliorated subchondral bone remodelling. Further studies showed that baicalein could decrease the number of differentiated osteoblasts by inhibiting pre-osteoblasts proliferation and promoting pre-osteoblasts apoptosis. In addition, baicalein impaired angiogenesis of endothelial cells and inhibited proliferation of synovial cells. Taken together, these results implicated that baicalein might be an effective medicine for treating OA by regulating multiple targets.     

KDM5A silencing transcriptionally suppresses the FXYD3-PI3K/AKT axis to inhibit angiogenesis in hepatocellular cancer via miR-433 up-regulation

Hepatocellular cancer (HCC) has been reported to belong to one of the highly vascularized solid tumours accompanied with angiogenesis of human umbilical vein endothelial cells (HUVECs). KDM5A, an attractive drug target, plays a critical role in diverse physiological processes. Thus, this study aims to investigate its role in angiogenesis and underlying mechanisms in HCC. ChIP-qPCR was utilized to validate enrichment of H3K4me3 and KDM5A on the promotor region of miR-433, while dual luciferase assay was carried out to confirm the targeting relationship between miR-433 and FXYD3. Scratch assay, transwell assay, Edu assay, pseudo-tube formation assay and mice with xenografted tumours were conducted to investigate the physiological function of KDM5A-miR-433-FXYD3-PI3K-AKT axis in the progression of HCC after loss- and gain-function assays. KDM5A p-p85 and p-AKT were highly expressed but miR-433 was down-regulated in HCC tissues and cell lines. Depletion of KDM5A led to reduced migrative, invasive and proliferative capacities in HCC cells, including growth and a lowered HUVEC angiogenic capacity in vitro. Furthermore, KDM5A suppressed the expression of miR-433 by demethylating H3K4me3 on its promoterregion. miR-433 negatively targeted FXYD3. Depleting miR-433 or re-expressing FXYD3 restores the reduced migrative, invasive and proliferative capacities, and lowers the HUVEC angiogenic capacity caused by silencing KDM5A. Therefore, KDM5A silencing significantly suppresses HCC tumorigenesis in vivo, accompanied with down-regulated miR-433 and up-regulated FXYD3-PI3K-AKT axis in tumour tissues. Lastly, KDM5A activates the FXYD3-PI3K-AKT axis to enhance angiogenesis in HCC by suppressing miR-433.     

Porcine placental immunoexpression of vascular endothelial growth factor,placenta growth factor,Flt-1 and Flk-1

Porcine embryo mortalities cause economic losses. Development of the placental vascular bed is required for successful gestation and postnatal survival. We studied the temporal and spatial distributions of vascular endothelial growth factor (VEGF), placenta growth factor (PlGF) and their receptors, Flt-1 and Flk-1. We used crossbred swine placental tissues from 30, 60, 80, 90 and 114 (term) days of gestation. Both VEGF and PlGF were present during gestation. At early pregnancy and at term, VEGF probably acts through Flt-1; during intermediate periods, its function is mediated by Flk-1. By day 90, factors other than members of VEGF family appear to be involved.     

Immunohistochemistry in the evaluation of neovascularization in tumor xenografts

Angiogenesis, or neovascularization, is known to play an important role in the neoplastic progression leading to metastasis. CD31 or Factor VIII-related antigen (F VIII RAg) immunohistochemistry is widely used in experimental studies for quantifying tumor neovascularization in immunocompromised animal models implanted with transformed human cell lines. Quantification, however, can be affected by variations in the methodology used to measure vascularization including antibody selection, antigen retrieval (AR) pretreatment, and evaluation techniques. To examine this further, we investigated the microvessel density (MVD) and the intensity of microvascular staining among five different human tumor xenografts and a mouse syngeneic tumor using anti-CD31 and F VIII RAg immunohistochemical staining. Different AR methods also were evaluated. Maximal retrieval of CD31 was achieved using 0.5 M Tris (pH 10) buffer, while maximum retrieval of F VIII RAg was achieved using 0.05% pepsin treatment of tissue sections. For each optimized retrieval condition, anti-CD31 highlighted small vessels better than F VIII RAg. Furthermore, the MVD of CD31 was significantly greater than that of F VIII RAg decorated vessels (p<0.001). The choice of antibody and AR method has a significant affect on immunohistochemical findings when studying angiogenesis. One also must use caution when comparing studies in the literature that use different techniques and reagents.     

A computational model of in vitro angiogenesis based on extracellular matrix fibre orientation

Recent interest in the process of vascularisation within the biomedical community has motivated numerous new research efforts focusing on the process of angiogenesis. Although the role of chemical factors during angiogenesis has been well documented, the role of mechanical factors, such as the interaction between angiogenic vessels and the extracellular matrix, remains poorly understood. In vitro methods for studying angiogenesis exist; however, measurements available using such techniques often suffer from limited spatial and temporal resolutions. For this reason, computational models have been extensively employed to investigate various aspects of angiogenesis. This paper outlines the formulation and validation of a simple and robust computational model developed to accurately simulate angiogenesis based on length, branching and orientation morphometrics collected from vascularised tissue constructs. Microvessels were represented as a series of connected line segments. The morphology of the vessels was determined by a linear combination of the collagen fibre orientation, the vessel density gradient and a random walk component. Excellent agreement was observed between computational and experimental morphometric data over time. Computational predictions of microvessel orientation within an anisotropic matrix correlated well with experimental data. The accuracy of this modelling approach makes it a valuable platform for investigating the role of mechanical interactions during angiogenesis.