Control of angiogenesis by VEGF and endostatin-encapsulated protein microcrystals and inhibition of tumor angiogenesis

Encapsulation of cytokines within protein microcrystals (polyhedra) is a promising approach for the stabilization and delivery of therapeutic proteins. Here, we investigate the influence of vascular endothelial growth factor (VEGF) microcrystals and endostatin microcrystals on angiogenesis. VEGF was successfully encapsulated into microcrystals derived from insect cypovirus with overexpression of protein disulfide bond isomerase. VEGF microcrystals were observed to increase the phosphorylation of p42/p44 MAP kinase and to stimulate the proliferation, migration, and network and tube formation of human umbilical vein endothelial cells (HUVECs). Endostatin was also successfully encapsulated into microcrystals. Endostatin microcrystals showed antiangiogenesis activities and inhibited the migration, and network and tube formation of HUVECs. Local administration of endostatin microcrystals in mice inhibited both angiogenesis and tumor growth with clear significant differences between treatment and control groups. Endostatin microcrystals only affected angiogenesis, but had no significant effect on lymphangiogenesis compared to controls. Local therapy using endostatin microcrystals offers a potential approach to achieve sustained therapeutic release of antiangiogenic molecules for cancer treatment.     

PTEN、VEGF、COX-2与JAK2 V617F突变阳性骨髓增殖性肿瘤血管新生

 目的:观察PTEN、VEGF、COX-2在JAK2 V617F突变阳性骨髓增殖性肿瘤(MPN)患者骨髓中的表达与血管新生之间的相互关系。方法:收集保定市第一医院住院及门诊42例JAK2V617F阳性的MPN患者(初治组27例,治疗组15例),其中原发性血小板增多症(ET)17例,真性红细胞增多症(PV)10例,原发性骨髓纤维化(PMF)15例;此外,选取10例特发性血小板减少性紫癜(ITP)患者作为对照。Real-time PCR检测突变型与野生型JAK2比值。免疫组化检测患者及对照骨髓病理切片p-JAK2、PTEN、VEGF、COX-2的蛋白水平及CD105标记的微血管密度(MVD)。结果:初治患者p-JAK2、VEGF、COX-2及MVD水平明显高于对照组,而PTEN表达水平明显低于对照组。治疗组患者p-JAK2、VEGF、COX-2及MVD的水平明显低于初治组,但PTEN表达水平高于初治组。JAK2 V617F突变量与VEGF、COX-2及MVD呈正相关(P<0.05)。PTEN与VEGF及MVD负相关(P<0.05)。JAK2突变型与野生型比值≥0.5的患者p-JAK2、VEGF、COX-2及MVD均明显高于比值<0.5的患者,而PTEN与上述相反。结论:PTEN、VEGF、COX-2与JAK2 V617F共同参与了骨髓增殖性肿瘤患者血管新生。     

Engineering strategies to control vascular endothelial growth factor stability and levels in a collagen matrix for angiogenesis: The role of heparin sodium salt and the PLGA-based microsphere approach

New vessel formation is the result of the complex orchestration of various elements, such as cells, signalling molecules and extracellular matrix (ECM). In order to establish the suitable conditions for an effective cell response, the influence of vascular endothelial growth factor (VEGF) complexation with heparin sodium salt (Hp) on its pro-angiogenic activity has been evaluated by an in vitro capillary-like tube formation assay. VEGF with or without Hp was embedded into collagen gels, and the activated matrices were characterized in terms of VEGF activity and release kinetics. Taking into account the crucial role of Hp in VEGF stability and activity, VEGF/Hp complex was then encapsulated into microspheres based on poly(lactide-co-glycolide) (PLGA), and microsphere properties, VEGF/Hp release kinetics and VEGF in vitro activity over time were evaluated. Integrated microsphere/collagen matrices were developed in order to provide a continuous release of active VEGF/Hp inside the matrix but also a VEGF gradient at the boundary, which is an essential condition for endothelial cell attraction and scaffold invasion. The results confirmed a strong influence of Hp on VEGF configuration and, consequently, on its activity, while the encapsulation of VEGF/Hp complex in PLGA-microspheres guaranteed a sustained release of active VEGF for more than 30 days. This paper confirms the importance of VEGF stability and signal presentation to cells for an effective proangiogenic activity and highlights how the combination of two stabilizing approaches, namely VEGF/Hp complexation and entrapment within PLGA-based microspheres, may be a very effective strategy to achieve this goal.     

Dalteparin, a low-molecular-weight heparin, promotes angiogenesis mediated by heparin-binding VEGF-A in vivo

Norrby K, Nordenhem A. Dalteparin, a low‐molecular‐weight heparin, promotes angiogenesis mediated by heparin‐binding VEGF‐A in vivo. APMIS 2010; 118: 949–57. Tumors are angiogenesis dependent and vascular endothelial growth factor‐A (VEGF‐A), a heparin‐binding protein, is a key angiogenic factor. As chemotherapy and co‐treatment with anticoagulant low‐molecular‐weight heparin (LMWH) are common in cancer patients, we investigated whether angiogenesis in vivo mediated by VEGF‐A is modulated by metronomic‐type treatment with: (i) the LMWH dalteparin; (ii) low‐dosage cytostatic epirubicin; or (iii) a combination of these two drugs. Using the quantitative rat mesentery angiogenesis assay, in which angiogenesis was induced by intraperitoneal injection of very low doses of VEGF, dalteparin sodium (Fragmin^®) and epirubicin (Farmorubicin^®) were administered separately or in combination by continuous subcutaneous infusion at a constant rate for 14 consecutive days. Dalteparin was administered at 27, 80, or 240 IU/kg/day, i.e., doses that reflect the clinical usage of this drug, while epirubicin was given at the well‐tolerated dosage of 0.4 mg/kg/day. While dalteparin significantly stimulated angiogenesis in an inversely dose‐dependent manner, epirubicin did not significantly affect angiogenesis. However, concurrent treatment with dalteparin and epirubicin significantly inhibited angiogenesis. The effect of dalteparin is the first demonstration of a proangiogenic effect of any LMWH in vivo. The fact that co‐treatment with dalteparin and epirubicin significantly inhibited angiogenesis suggests a complex drug effect.     

In vivo inhibition of tumor angiogenesis by a soluble VEGFR-2 fragment

The interaction of vessel endothelial cell growth factor (VEGF) and its receptors (flt-1, FLK-1/KDR) regulates tumor angiogenesis. Therefore, blocking the binding of VEGF and the corresponding receptor has become critical for antitumor angiogenesis biological therapy. Our study extracted sFLK-1 fragment from embryo mouse liver using RT-PCR, recombined it to retrovirus vector, and transfected it to tumor cell lines (S180 and B16) by the liposome mediated method, then we observed the biological behavior of transgenic cells in vivo. The results are: (1) Fragment (1034 bp) was extracted from E9, E11 embryo mouse liver tissue, which was identified by sequence analysis. (2) This fragment was cloned to retrovirus vector (PLXSN vector), which was further transfected to tumor cells lines (S180 and B16). SDS-PAGE indicated the suspension of transgenic cells present sVEGFR-2(sFLK-1) fragment; Western blot identified it. (3) In vivo study showed that the weight and size of tumor in the group of transgenic cells were smaller than in control groups. Microvessel density (MVD) and FLK-1 expression were obviously different between transgenic and control groups, but there were no differences in VEGF expression between transgenic and control groups. In short, the isolated soluble VEGFR2 fragment transfected to tumor cells can be secreted to extracellular suspension and can inhibit tumor angiogenesis in vivo.     

VEGF通过上调CCN2促HUVEC迁移和血管生成

目的 探讨血管内皮生长因子(VEGF)诱导的成骨细胞中结缔组织生长因子(CTGF/CCN2)对人脐静脉血管内皮细胞(HUVECs)的影响.方法 用Real time PCR法及ELISA法检测VEGF诱导成骨细胞(OSE)中CCN2含量;制备成骨细胞(OSE)上清液;将细胞分为control组、OSE组和VEGF-OSE组(n=3).用小干扰RNA (siRNA)转染法抑制成骨细胞中CCN2的表达;Transwell法检测内皮细胞迁移;Matrigel实验检测管样结构形成能力.结果 VEGF呈时间和剂量依赖性上调成骨细胞中CCN2 mRNA和蛋白的表达;CCN2可促进内皮细胞的迁移和管样结构形成(P＜0.05),当CCN2被siRNA基因沉默或者加入CCN2抗体后,CCN2对内皮细胞迁移和管样结构形成的促进作用均受到明显抑制(P＜0.05).结论 VEGF通过上调成骨细胞中CCN2的表达,促内皮细胞(HUVECs)的迁移和血管生成.     

Immunolocalization of VEGF, VEGF receptors, EGF-R and Ki-67 in leiomyoma, cellular leiomyoma and leiomyosarcoma

Angiogenic factors, such as vascular endothelial growth factor (VEGF), its receptors and epidermal growth factor receptor (EGF-R), are involved in increased progression in many carcinomas. The aim of this study was to investigate the role of angiogenesis and immunolocalization of VEGF, its receptors, EGF-R and Ki 67 in leiomyomas and leiomyosarcomas using an indirect immunohistochemical method. Samples from patients with leiomyoma, cellular leiomyoma and cellular leiomyosarcoma (n=20 per group) were fixed in 10% formalin and processed using routine paraffin protocols. Following initial histological analysis, samples were immunostained with primary antibodies for VEGF, VEGFR-1, VEGFR-2, EGF-R and Ki-67 using an indirect avidin-biotin peroxidase method. Immunostaining intensities were evaluated as mild, moderate or strong and a semi-quantitative method (H-Score) was used to compare the samples. While mild/moderate EGF-R immunostaining and moderate immunostaining for VEGF and its receptors were observed in samples of leiomyomas, much less immunoreactivity was observed in cellular leiomyomas. All immunoreactivities and immune-stained cells increased in leiomyosarcomas. When scores of intensity and percentage of positive staining cells were compared, all immunoreactivities were shown to be significantly increased in leiomyosarcomas compared to leiomyomas.These results suggest that in leiomyosarcoma, angiogenic factors, such as VEGF, its receptors and EGF-R, may be involved in tumor angiogenesis. Active tumor cells can trigger angiogenesis, interaction with surrounding tissue and in the tissue itself initiating angiogenic activity. Angiogenic growth factors play an important role and induce malignant transformation through both autocrine and paracrine mechanisms. Anti-angiogenic agents may provide a novel therapeutic approach for the treatment of leiomyosarcoma.     

Engeletin protects against cerebral ischemia/reperfusion injury by modulating the VEGF/vasohibin and Ang-1/Tie-2 pathways

Engeletin is a natural derivative of Smilax glabra rhizomilax that exhibits anti-inflammatory activity and suppresses lipid peroxidation. In the present study, we sought to elucidate the mechanistic basis for the neuroprotective and pro-angiogenic activity of engeltin in a human umbilical vein endothelial cells (HUVECs) oxygen-glucose deprivation and reoxygenation (OGD/R) model system and a middle cerebral artery occlusion (MCAO) rat model of cerebral ischemia and reperfusion injury. These analyses revealed that engeletin (10, 20, or 40 mg/kg) was able to reduce the infarct volume, increase cerebral blood flow, improve neurological function, and bolster the expression of vascular endothelial growth factor (VEGF), vasohibin-2 (Vash-2), angiopoietin-1 (Ang-1), phosphorylated human angiopoietin receptor tyrosine kinase 2 (p-Tie2), and platelet endothelial cell adhesion molecule-1 (PECAM-1/CD31) in MCAO rats. Similarly, engeletin (100, 200, or 400 nM) markedly enhanced the migration, tube formation, and VEGF expression of HUVECs in an OGD/R model system, while the VEGF receptor (R) inhibitor axitinib reversed the observed changes in HUVEC tube formation activity and Vash-2, VEGF, and CD31 expression. These data suggested that engeletin exhibited significant neuroprotective effects against cerebral ischemia and reperfusion injury in rats, and improved cerebrovascular angiogenesis by modulating the VEGF/vasohibin and Ang-1/Tie-2 pathways.     

Molecular studies on the roles of Runx2 and Twist1 in regulating FGF signaling

Background: Supernumerary teeth are often observed in patients suffering from cleidocranial dysplasia due to a mutation in Runx2 that results in haploinsufficiency. However, the underlying molecular mechanisms are poorly defined. In this study, we assessed the roles of Runx2 and its functional antagonist Twist1 in regulating fibroblast growth factor (FGF) signaling using in vitro biochemical approaches. Results: We showed that Twist1 stimulated Fgfr2 and Fgf10 expression in a mesenchymal cell line and that it formed heterodimers with ubiquitously expressed E12 (together with E47 encoded by E2A gene) and upregulated Fgfr2 and Fgf10 promoter activities in a dental mesenchyme‐derived cell line. We further demonstrated that the bHLH domain of Twist1 was essential for its synergistic activation of Fgfr2 promoter with E12 and that the binding of E12 stabilized Twist1 by preventing it from undergoing lysosomal degradation. Although Runx2 had no apparent effects on Fgfr2 and Fgf10 promoter activities, it inhibited the stimulatory activity of Twist1 on Fgfr2 promoter. Conclusions: These findings suggest that Runx2 haploinsufficiency might result in excessive unbound Twist1 that can freely bind to E12 and enhance FGF signaling, thereby promoting the formation of extra teeth. Developmental Dynamics 241:1708–1715, 2012. © 2012 Wiley Periodicals, Inc.     

Oral delivery of a potent anti-angiogenic heparin conjugate by chemical conjugation and physical complexation using deoxycholic acid

Angiogenesis, the formation of new blood vessels, plays a pivotal role in tumor progression and for this reason angiogenesis inhibitors are an important class of therapeutics for cancer treatment. Heparin-based angiogenesis inhibitors have been newly developed as one of such classes of therapeutics and possess a great promise in the clinical context. Taurocholate conjugated low molecular weight heparin derivative (LHT7) has been proven to be a potent, multi-targeting angiogenesis inhibitor against broad-spectrum angiogenic tumors. However, major limitations of LHT7 are its poor oral bioavailability, short half-life, and frequent parenteral dosing schedule. Addressing these issues, we have developed an oral formulation of LHT7 by chemically conjugating LHT7 with a tetrameric deoxycholic acid named LHTD4, and then physically complexing it with deoxycholylethylamine (DCK). The resulting LHTD4/DCK complex showed significantly enhanced oral bioavailability (34.3 ± 2.89%) and prolonged the mean residence time (7.5 ± 0.5 h). The LHTD4/DCK complex was mostly absorbed in the intestine by transcellular pathway via its interaction with apical sodium bile acid transporter. In vitro, the VEGF-induced sprouting of endothelial spheroids was significantly blocked by LHTD4. LHTD4/DCK complex significantly regressed the total vessel fractions of tumor (77.2 ± 3.9%), as analyzed by X-ray microCT angiography, thereby inhibiting tumor growth in vivo. Using the oral route of administration, we showed that LHTD4/DCK complex could be effective and chronically administered as angiogenesis inhibitor.     

miR-195 is a key negative regulator of hepatocellular carcinoma metastasis by targeting FGF2 and VEGFA

Hepatocellular carcinoma (HCC) is the most common primary tumor of liver and the fifth most common cancer in the world. Lung is the most frequent site for extra hepatic metastasis from hepatocellular carcinoma, while the cause and mechanism of it is still poor understood. Here, we identify that the expression of miR-195 is markedly impaired in the lung metastasis cell lines of HCC. The result of Real-time PCR reveals the expression of miR-195 is significantly downregulated in 92 HCC tissues. Low expression of miR-195 is associated with tumor size, portal vein thrombosis, TNM stage and patients survival. Luciferase reporter and ELISA assay prove that hematogenous metastasis related genes including FGF2 and VEGFA are the target genes of miR-195. Overexpression of miR-195 in HCC cell line BEL-7402 markedly inhibits the capability of migration and invasion. Taken together, our results suggest that miR-195, a tumor suppressor miRNA, contributes to the lung metastasis of HCC by negatively regulating FGF2 and VEGFA, providing key implications of miR-195 for the therapeutic intervention of HCC.     

Xanthatin,a novel potent inhibitor of VEGFR2 signaling,inhibits angiogenesis and tumor growth in breast cancer cells

Anti-angiogenesis targeting vascular endothelial growth factor receptor 2 (VEGFR2) has emerged as an important tool for cancer treatment. In this study, we described a novel VEGFR2 inhibitor, xanthatin, which inhibits tumor angiogenesis and growth. The biochemical profiles of xanthatin were investigated using kinase assay, migration assay, tube formation, Matrigel plug assay, western blot, immunofluorescence and human tumor xenograft model. Xanthatin significantly inhibited growth, migration and tube formation of human umbilical vascular endothelial cell as well as inhibited vascular endothelial growth factor (VEGF)-stimulated angiogenesis. In addition, it inhibited VEGF-induced phosphorylation of VEGFR2 and its downstream signaling regulator. Moreover, xanthatin directly inhibit proliferation of breast cancer cells MDA-MB-231. Oral administration of xanthatin could markedly inhibit human tumor xenograft growth and decreased microvessel densities (MVD) in tumor sections. Taken together, these preclinical evaluations suggest that xanthatin inhibits angiogenesis and may be a promising anticancer drug candidate.     

Prostaglandin D2 inhibits the production of interleukin-12 in murine dendritic cells through multiple signaling pathways

Prostaglandin (PG) D(2), and its metabolites, are known to be important mediators during acute and chronic inflammation. However, their functions during the early phases of the immune response are poorly documented. In the present study, we show that PGD(2 )inhibits, in a dose-dependent manner, the CD40- and LPS-induced secretion of the Th1-driving factor IL-12 by murine splenic dendritic cells (DC), the most potent antigen-presenting cells. The inhibition of IL-12 production is mediated only in part by the cell surface G alpha s protein-coupled D prostanoid receptor (termed DP1) but not by the G alpha i protein-coupled DP receptor, DP2. We show that recruitment of DP1 in DC results in the activation of a cyclic AMP/protein kinase A pathway that is partially responsible for the inhibition of IL-12 production. We also suggest that the DP1-independent effects exerted by PGD(2) on IL-12 production may be due to the action of ist PGJ(2), but not PGF(2)alpha, metabolites. Electrophoretic mobility shift assays demonstrated that PGD(2) affects NF-kappa B activation through (the) DP1-independent pathway(s). Together these data suggest that PGD(2), by interacting with DP1 and by binding to other target cellular proteins, may regulate immune responses by affecting IL-12 production in DC.     

miR-23a-3p suppresses cell proliferation in oral squamous cell carcinomas by targeting FGF2 and correlates with a better prognosis: miR-23a-3p inhibits OSCC growth by targeting FGF2

Oral squamous cell carcinomas (OSCCs) are one of the most ubiquitous malignancies the world over, and are accompanied by a high mortality. microRNAs (miRNAs) have increasingly garnered attention with regards to the roles they play in initiation and progression of various kinds of cancers, including OSCC. It has been reported, that miR-23a-3p promotes the development of tumors for prostate cancer, gastric cancer and gliomas. The functions of miR-23a-3p in OSCC however, remain unclear. In this study, fibroblast growth factor 2 (FGF2) is revealed as a direct target of miR-23a-3p, based on luciferase assays and immunoblotting. The expression of miR-23a-3p and FGF2 were found to be significantly downregulated and upregulated in OSCC tissues respectively. This indicates a reverse correlation between miR-23a-3p and FGF2 levels. Using in vitro approaches we ascertained that miR-23a-3p might contribute to the inhibition of growth and inhibition through increasing apoptosis in OSCC cells; while an inhibitor of miR-23a-3p could reverse this effect. Examination of a clinical cohort of OSCC patients suggested that reduced expression of miR-23a-3p is correlated with more advanced cancerous stage and poorer differentiation of OSCC cell. Additionally, a survival analysis and the Cox-hazard regression model showed that higher levels of miR-23a-3p can be used reliably for prognosis of OSCC patients. This study indicates that miR-23a-3p might suppress tumor proliferation, invasion and promote apoptosis of OSCC by targeting FGF2. miR-23a-3p has the potential to be used as prognostic indicator, and could be exploited as a therapeutic reagent for OSCC in the future.     

IgA肾病进展中MMP-2、TIMP-2与VEGF的表达变化

目的 探索在IgA肾病进展过程中MMP-2、TIMP-2与VEGF的表达变化、相互关系及其对逐渐进展的肾纤维化的影响.方法 收集60例确诊为IgA肾病的肾穿刺活检标本,将其分为5级,随机选取10例同期的肾小球微小病变作为对照组.利用免疫组化技术和图像分析技术检测病例组与对照组中MMP-2、TIMP-2、VEGF的表达.结果 随着IgA肾病进展,MMP-2和VEGF表达均在早期出现表达增强,随病变发展逐渐下降,TIMP-2表达强度则逐渐增加,MMP-2/TIMP-2的比值亦在短暂上升后出现下降.MMP-2与TIMP-2呈负相关关系,与VEGF呈正相关关系.结论 MMP-2/TIMP-2系统及VEGF的表达变化对于IgA肾病的进展具有重要影响,MMP-2/TIMP-2自然平衡的破坏对于肾纤维化过程具有关键性作用.     

Stimulation of angiogenesis and survival of endothelial cells by human monoclonal Tie2 receptor antibody

Angiopoietin-1 (Ang1) and its endothelium-specific receptor, tyrosine kinase with Ig and epidermal growth factor homology domain 2 (Tie2), play critical roles in vascular development. Although the Ang1/Tie2 system has been considered a promising target for therapeutic neovascularization, several imitations of large-scale production have hampered the development of recombinant Ang1 for therapeutics. In this study, we produced a fully human agonistic antibody against Tie2, designated 1–4h, and tested the applicability of 1–4h as an alternative to native Ang1 in therapeutic angiogenesis. 1–4h significantly enhanced the phosphorylation of Tie2 in a dose- and time-dependent manner in human Tie2-expressing HEK293 cells and human umbilical vein endothelial cells. Moreover, 1–4h induced the activation of Tie2-mediated intracellular signaling such as AKT, eNOS, MAPK, and Focal Adhesion Kinase p125^FAK. In addition, 1–4h increased the chemotactic motility and capillary-like tube formation of endothelial cells in vitro and enhanced the survival of serum-deprived endothelial cells. Taken together, our data clearly suggest that a human Tie2 agonistic antibody is a potentially useful therapeutic approach for the treatment of several ischemic diseases including delayed-wound healing and ischemic heart and limb diseases.     

虫草素通过ERK1/2、Ezrin和Akt信号通路抑制胆囊癌细胞SNU-308的增殖和迁移

目的:探讨虫草素对胆囊癌细胞SNU-308增殖和迁移的影响及其分子机制。方法:MTT法和平板集落形成实验检测不同浓度虫草素对胆囊癌SNU-308细胞活力和集落形成能力的影响;Annexin V/PI双染法检测细胞凋亡率;Western blot法检测细胞凋亡和自噬相关蛋白以及Akt、ERK1/2和Ezrin蛋白的磷酸化水平;免疫荧光染色法检测细胞内LC3的表达水平;划痕愈合实验和Transwell实验检测虫草素对胆囊癌细胞迁移能力的影响;划痕实验检测Akt抑制剂和ERK1/2抑制剂及Ezrin基因沉默对细胞迁移能力的影响。结果:虫草素可显著抑制胆囊癌细胞的活力和集落形成能力(P0.05)。流式细胞术结果显示,虫草素可诱导胆囊癌细胞凋亡(P0.05)。Western blot结果显示,虫草素处理后Bcl-2表达降低,Bax、细胞色素C(Cyto C)、Fas、Fas L和cleaved caspase-3蛋白水平升高,自噬标识蛋白LC3-II/I比例和beclin 1表达上调(P0.05)。免疫荧光染色结果显示,虫草素处理后SNU-308细胞胞浆中LC3荧光颗粒的数量明显增多。划痕实验和Transwell实验结果显示虫草素可抑制细胞迁移(P0.05)。虫草素明显抑制Akt、ERK1/2和Ezrin蛋白的磷酸化水平(P0.05)。Ezrin基因沉默及Akti-1/2和GDC-0994均可抑制胆囊癌细胞的迁移作用(P0.05)。结论:虫草素通过诱导凋亡和自噬抑制胆囊癌细胞的增殖和迁移,其机制可能与调控ERK1/2,Ezrin和Akt信号通路有关。