Vascular endothelial growth factor (VEGF), transforming growth factor beta (TGFß), angiostatin, and endostatin are increased in radiotherapy-induced gastrointestinal toxicity.

PURPOSE: Radiotherapy-induced gut toxicity (RIGT) is a debilitating effect of radiotherapy for cancer, often resulting in significant diarrhea and pain. Previous studies have highlighted roles of the intestinal microvasculature and matrix metalloproteinases (MMPs) in the development of RIGT. We hypothesized vascular mediators would be significantly altered in a dark agouti (DA) rat model of RIGT. Additionally, we aimed to assess the effect of MMP-2 and -9 inhibition on the response of tumor-associated microvascular endothelial cells (TAMECs) to radiation. METHODS: DA rats were administered 2.5 Gy abdominal irradiation (3 times/week over 6 weeks). Vascular endothelial growth factor (VEGF), transforming growth factor beta (TGFß), von Willebrand factor (VWF), angiostatin, and endostatin expression was assessed at 3, 6, and 15 weeks. Additionally, DA rat mammary adenocarcinoma tumor-associated microvascular endothelial cells (TAMECs) were used to assess the effects of radiation (12 Gy) and the MMP inhibitor SB-3CT on MMP, VEGF, and TGFß expression, and cell viability. RESULTS: VEGF mRNA expression was significantly increased in the colon at week 15 (p = .0012), and TGFß mRNA expression was significantly increased in both the jejunum and colon at week 3 (p = .0280 and p = .0310, respectively). Endostatin immunostaining was significantly increased at week 3 (p = .0046), and angiostatin at 3 and 6 weeks (p = .0022 and p = .0135, respectively). MMP-2 and -9 mRNA and total protein levels were significantly increased following irradiation of TAMECs. Although this increase was significantly attenuated by SB-3CT, it did not significantly alter endothelial cell viability or VEGF and TGFß mRNA expression. CONCLUSIONS: Findings of this study support the involvement of VEGF, TGFß, angiostatin, endostatin, and MMP-2 in the pathobiology of RIGT. However, the relationship between these mediators is complex and needs further investigation to improve understanding of their therapeutic potential in RIGT.

Effect of hypoxia on angiogenesis related factors in glioblastoma cells.

Pathological angiogenesis is a characteristic feature of glioblastoma multiforme (GBM) where the balance between pro-angiogenic and anti-angiogenic factors are shifted towards the pro-angiogenic phenotype. In this study we sought to determine whether angiostatins are expressed by GBM cells and whether their expression along with other related factors [matrix metalloproteinase (MMP)-2, MMP-9, and collagen type I α1 (COLIA1)] are altered by hypoxia and/or correlated with the levels of cancer stem cell marker CD133. Using qRT-PCR, western blotting, and gelatin zymography, we examined the expression of angiostatins, MMP-2, MMP-9, COLIA1 and CD133 in GBM cell lines cultured under aerobic conditions and hypoxia. Expression levels of MMP-2 and MMP-9 were significantly induced by hypoxia. Angiostatins were detected in all GBM cell lines and were increased by hypoxia while the angiostatin isoform of 38-kDa was the most abundant in GBM cells under aerobic and hypoxic conditions. COLIA1 and CD133 were significantly increased in several GBM cell lines under hypoxia. Despite expression and upregulation of anti-angiogenic factors (e.g. angiostatins) in GBM cells, they are overwhelmed by the overexpression of a larger number of angiogenic factors that shift the angiogenic balance towards the pro-angiogenic phenotype. Thus, an exogenous administration of anti-angiogenic factors may be required to improve the treatment of GBM tumors.

Impaired coronary collateral growth in the metabolic syndrome is in part mediated by matrix metalloproteinase 12-dependent production of endostatin and angiostatin.

OBJECTIVE: We have previously shown that transient coronary artery occlusion stimulated coronary collateral growth (CCG) in healthy (Sprague Dawley) but not in metabolic syndrome (JCR:LA-cp [JCR] ) rats. Here, we sought to determine whether matrix metalloproteinases (MMPs) negatively regulate CCG in the metabolic syndrome via release of endostatin and angiostatin. APPROACH AND RESULTS: Rats underwent transient, repetitive left anterior descending occlusion and resultant myocardial ischemia (RI) for 0 to 10 days. CCG was measured in the collateral-dependent and normal zones using microspheres, MMP activation by Western blot, and endostatin and angiostatin by ELISA on days 0, 3, 6, 9, or 10 of RI. Endostatin and angiostatin were increased in JCR but not in Sprague Dawley rats on days 6 and 9 of RI. Increased endostatin and angiostatin correlated with increased MMP12 (≈ 4-fold) activation in JCR but not in Sprague Dawley rats on days 6 and 9 of RI. Inhibition of MMP12 in JCR rats nearly completely blocked endostatin (≈ 85%) and angiostatin (≈ 90%) generation and significantly improved CCG (collateral-dependent zone flow was ≈ 66% of normal zone flow versus ≈ 12% for JCR RI). CONCLUSIONS: Compromised CCG in the metabolic syndrome is, in large part, because of increased MMP12 activation and consequent increased generation of endostatin and angiostatin, which inhibits late-stage collateral remodeling.

Angiogenic biomarkers and healing of living cellular constructs.

The use of intra-oral soft-tissue-engineered devices has demonstrated potential for oral mucosa regeneration. The aim of this study was to investigate the temporal expression of angiogenic biomarkers during wound healing of soft tissue reconstructive procedures comparing living cellular constructs (LCC) with autogenous free gingival grafts. Forty-four human participants bilaterally lacking sufficient zones of attached keratinized gingiva were randomly assigned to soft tissue surgery plus either LCC or autograft. Wound fluid samples were collected at baseline and weeks 1, 2, 3, and 4 post-operatively and analyzed for a panel of angiogenic biomarkers: angiogenin (ANG), angiostatin (ANT), PDGF-BB, VEGF, FGF-2, IL-8, TIMP-1, TIMP-2, GM-CSF, and IP-10. Results demonstrated a significant increase in expression of ANT, PDGF-BB, VEGF, FGF-2, and IL-8 for the LCC group over the autograft group at the early stages of wound repair. Although angiogenic biomarkers were modestly elevated for the LCC group, no clinical correlation with wound healing was found. This human investigation demonstrates that, during early wound-healing events, expression of angiogenic-related biomarkers is up-regulated in sites treated with LCC compared with autogenous free gingival grafts, which may provide a safe and effective alternative for regenerating intra-oral soft tissues (ClinicalTrials.gov number, NCT01134081).

Endostatin and angiostatin are increased in diabetic patients with coronary artery disease and associated with impaired coronary collateral formation.

Coronary artery disease (CAD) is the leading cause of mortality in diabetic patients. Because of the diffuse nature of their disease, diabetic patients may be at risk for incomplete revascularization, highlighting a potential role for proangiogenic therapy in this group. This study investigates molecular mechanisms of angiogenesis in diabetic patients. Myocardial tissue was harvested from patients undergoing coronary artery bypass grafting [nondiabetic (ND) 11, type 2 diabetic (DM) 10]. Expression of angiostatin, endostatin, their precursors (plasminogen and collagen XVIII, respectively), enzymes leading to their production [matrix metalloprotease (MMP)-2 and -9, cathepsin L], and an inhibitor of MMPs (tissue inhibitor of metalloproteinase) was assessed with Western blotting. MMP activity was assessed. Coronary collateralization was graded by Rentrop scoring of angiograms. Plasminogen and collagen XVIII expression were similar between groups. Angiostatin expression trended to increase 1.24-fold (P = 0.07), and endostatin expression increased 2.02-fold in DM patients relative to ND (P = 0.02). MMP-9 expression was no different between groups, whereas MMP-2 expression decreased 1.8-fold in diabetics (P = 0.003). MMP-2 and -9 activity decreased 1.33-fold (P = 0.03) and 1.57-fold (P = 0.04), respectively, in diabetic patients. Cathepsin L expression was 1.38-fold higher in diabetic patients (P = 0.02). Coronary collateralization scores were ND 2.1 +/- 0.37 vs. DM 1.0 +/- 0.4 (P = 0.05). Myocardial endostatin expression correlated strongly with the percentage of hemoglobin A(1c) (r = 0.742, P = 0.0001). Myocardial expression of angiostatin and endostatin demonstrated significant negative linear correlations with coronary collateralization (angiostatin r = -0.531, P = 0.035, endostatin r = -0.794, P = 0.0002). Diabetic patients with CAD exhibit increased levels of the antiangiogenic proteins angiostatin and endostatin and differential regulation of the enzymes governing their production relative to ND patients. Myocardial levels of these proteins show significant correlation to coronary collateralization. These findings offer potential new therapeutic targets for enhancing proangiogenic therapy and insight into the angiogenic impairments seen in diabetes.

Angiostatin and integrin alphavbeta3 in the feline, bovine, canine, equine, porcine and murine retina and cornea.

PURPOSE: Angiogenesis is tightly controlled in the ocular tissues of domestic animals but its mechanisms are not fully understood. This is largely because of insufficient data on the expression of molecules that impact angiogenesis. Because angiostatin and one of its receptors integrin alphavbeta3 inhibit and promote angiogenesis, respectively, we hypothesized that the normal retina and cornea of domestic animals would express angiostatin but not integrin alphavbeta3. PROCEDURE: Normal eyes of the cat, cow, dog, horse, pig and rat were evaluated for angiostatin and integrin alphavbeta3 by light and electron immunocytochemistry and estern blots. RESULTS: Angiostatin was detected in the corneal epithelium of the cat, dog, horse, pig and rat, but was not found in cow corneal epithelium. Angiostatin was localized in the nerve fiber layer, ganglion cell layer, inner and outer plexiform layers, and the photoreceptor layer of the cat, cow, dog and rat. Horse and pig retinas showed additional staining in the matrix of the inner nuclear layer. Immunogold electron microscopy further confirmed angiostatin in cat retina. Western blots showed angiostatin in corneal and retinal homogenates. Integrin alphavbeta3 was absent in cornea and retina of all the species studied. CONCLUSION: These data show that angiostatin, an inhibitor of angiogenesis, is present while integrin alphavbeta3, which promotes angiogenesis, is absent in normal cornea and retina of the domestic animals in this study with the exception being angiostatin absence in cow corneal epithelium. Therefore, angiostatin may contribute to the anti-angiogenic environment in the normal domestic animal eye while its absence in the cow may contribute to greater propensity for corneal vascularization. Because integrin alphavbeta3 is one of the receptors for angiostatin, its absence may prevent angiostatin from killing normal retinal and corneal cells.

Expression of angiostatin, integrin alphavbeta3, and vitronectin in human lungs in sepsis.

Angiostatin, integrin alphavbeta3, and vitronectin play important roles in inflammation. However, there is very little information on expression of these molecules in the lungs of humans with sepsis. Therefore, as a first step to eventually study the function of these molecules, the authors conducted an immunohistochemical study to evaluate their expression in lungs of normal (N = 8) and sepsis patients (N = 8). In normal lungs, angiostatin expression was minimal in the alveolar septa and alveolar macrophages, and absent in large blood vessels, bronchioles, and interstitium. In sepsis patients, the staining was intense in the septa, neutrophils, alveolar macrophages, and large blood vessels. Integrin alphavbeta3 staining was observed in occasional bronchiolar epithelial cells and a few alveolar macrophages in the normal lungs. The integrin was expressed extensively and intensely in bronchiolar epithelium and alveolar macrophages, and with lesser intensity in large blood vessels in inflamed lungs. Compared to the normal lung, vitronectin expression was increased in alveolar macrophages and in vascular smooth muscles in inflamed lungs. These data show cell-specific increase in the expression of integrin alphavbeta3, angiostatin, and vitronectin in inflamed lungs of sepsis patients. Because all these molecules can have significant influence on inflammation, the data reported in this manuscript create a need for further investigation.

Quantitative analysis of vascular endothelial growth factor, microvascular density and their clinicopathologic features in human hepatocellular carcinoma.

BACKGROUND: Angiogenesis is known to be essential to the survival, growth, invasion, and metastasis of tumor cells. Vascular endothelial growth factor (VEGF) are an important angiogenic factor regulating tumor angiogenesis, but its significance and tumor pathologic features are unclear in hepatocellular carcinoma (HCC). In the present study, we analyzed expression of tissue VEGF, alteration of microvascular density (MVD) in microvessel angiogenesis, development and metastasis of HCC, and level of serum VEGF in differential diagnosis of benign and malignant liver diseases. METHODS: Tumor specimens were prospectively collected from HCC patients undergoing resection. Total RNAs were extracted and the expression levels were detected from different parts of HCC tissues. The cellular distributions of VEGF and MVD of liver tumors and their paracancerous and distal cancerous tissues were investigated by streptavidin peroxidase (S-P) immunohistochemistry, respectively. The VEGF levels of circulating blood and hepatoma tissues were measured by enzyme-linked immunosorbent assay. RESULTS: The incidence of VEGF expression was 63.9% in HCCs (23/36 cases), 78.3% in non-encapsulated HCCs (18/23), and 90.9% in HCCs with extrahepatic metastasis (10/11), respectively. The VEGF expression was tightly correlated with MVD (P<0.01). The MVD in HCC with metastasis, low differentiation or non-encapsulation was significantly higher than that in HCC with intact capsule, high differentiation, or no metastasis. No significant difference was found between VEGF, MVD, tumor size, and hepatitis virus infection. The level of total RNA in HCC tissues was significantly lower but the VEGF level significantly higher than those in paracancerous or distal cancerous ones (P<0.01). The abnormal expression levels of VEGF in sera of HCC patients were directly correlated with the metastasis and recurrence of tumors. CONCLUSION: The high expression of VEGF and abnormality of tissue MVD are useful predictors for vascular invasion and metastasis of liver tumors.

[The role of angiostatin, vascular endothelial growth factor, matrix metalloproteinase 9 and 12 in the angiogenesis of hepatocellular carcinoma].

BACKGROUND/AIMS: Tumor angiogenesis, a major requirement for tumor growth and metastasis, is regulated by pro- and anti-angiogenic factors. Hepatocellular carcinoma (HCC) has become a common malignant tumor worldwide. It is characterized by a high vascularity. METHODS: We studied the immunohistochemical expression of angiostatin, vascular endothelial cell growth factor (VEGF), matrix metalloproteinase (MMP)-9 and MMP-12, and the relationship between these results and the microvessel density (MVD) in 48 HCC specimens. To determine whether HCC cells express angiostatin per se, we examined the expression of angiostatin, MMP-9 and MMP-12 by Western blotting in four HCC cell lines. RESULTS: Expression of angiostatin and MMP-12 (but not MMP-9) were strongly correlated with decreased MVD in HCCs (P=0.006, P=0.038, respectively). VEGF positive tumors showed a significantly higher MVD than VEGF negative tumors (P=0.01). We divided the 48 cases into the following four groups: group A, angiostatin (+), MMP-9 or -12 (+), and VEGF (-); group B, angiostatin (-) and VEGF (-); group C, angiostatin (+), MMP-9 or -12 (+), and VEGF (+); group D, angiostatin (-) and VEGF (+). There was a significant correlation with MVD among these groups (P<0.001). Angiostatin was detected by Western blotting in 2 out of 4 HCC cell lines and was associated with plasminogen and MMP expression. CONCLUSIONS: These results indicate that angiogenesis in HCC is a complex process involving multiple factors including angiostatin, VEGF, and MMP. Our results suggest that angiostatin is generated by MMP-mediated proteolysis of plasminogen in HCC cells.

The effects of surgery, with or without rhGM-CSF, on the angiogenic profile of patients treated for colorectal carcinoma.

Wound healing is a process with immunological and angiogenic aspects. rhGM-CSF is known to stimulate the immune system and angiogenesis via multiple pathways. In this study we investigated the combined effects of surgery, with or without rhGM-CSF, on angiogenic parameters in patients with a colorectal carcinoma. In this phase II randomized, placebo-controlled trial, 16 patients were assigned to perioperative rhGM-CSF (2.8 microg/kg body weight) treatment or saline. Patients received subcutaneous injections from three days before surgery until four days after. IL-6, VEGF, endostatin and angiostatin levels were measured perioperatively. rhGM-CSF enhanced the production of IL-6 and VEGF, but had no effect on the antiangiogenic agents endostatin and angiostatin. Surgery induced a transient decrease of endostatin. Two types of angiostatin (kringle 1-3 and kringle 1-4) became visible postoperatively. We conclude that this study demonstrated the immediate initiation of angiogenesis postoperatively, reflected by the increase of VEGF and a transient decrease of endostatin, followed by the appearance of two angiostatin bands, which confirms physiological wound healing in these cancer patients.

The Role of Angiostatin, Vascular Endothelial Growth Factor, Matrix Metalloproteinase 9 and 12 in the Angiogenesis of Hepatocellular Carcinoma / 대한간학회지

BACKGROUND/AIMS: Tumor angiogenesis, a major requirement for tumor growth and metastasis, is regulated by pro- and anti-angiogenic factors. Hepatocellular carcinoma (HCC) has become a common malignant tumor worldwide. It is characterized by a high vascularity. METHODS: We studied the immunohistochemical expression of angiostatin, vascular endothelial cell growth factor (VEGF), matrix metalloproteinase (MMP)-9 and MMP-12, and the relationship between these results and the microvessel density (MVD) in 48 HCC specimens. To determine whether HCC cells express angiostatin per se, we examined the expression of angiostatin, MMP-9 and MMP-12 by Western blotting in four HCC cell lines. RESULTS: Expression of angiostatin and MMP-12 (but not MMP-9) were strongly correlated with decreased MVD in HCCs (P=0.006, P=0.038, respectively). VEGF positive tumors showed a significantly higher MVD than VEGF negative tumors (P=0.01). We divided the 48 cases into the following four groups: group A, angiostatin (+), MMP-9 or -12 (+), and VEGF (-); group B, angiostatin (-) and VEGF (-); group C, angiostatin (+), MMP-9 or -12 (+), and VEGF (+); group D, angiostatin (-) and VEGF (+). There was a significant correlation with MVD among these groups (P<0.001). Angiostatin was detected by Western blotting in 2 out of 4 HCC cell lines and was associated with plasminogen and MMP expression. CONCLUSIONS: These results indicate that angiogenesis in HCC is a complex process involving multiple factors including angiostatin, VEGF, and MMP. Our results suggest that angiostatin is generated by MMP-mediated proteolysis of plasminogen in HCC cells.

Angiogenic proteins in brains of patients who died with cerebral malaria.

In cerebral malaria (CM), microvascular activation accompanies blood-brain barrier dysfunction which in turn represents the pathophysiological basis of neurological impairments in affected patients. To dissect the molecular basis of this process, we analyzed localization of proangiogenic vascular endothelial growth factor (VEGF), its receptor vascular endothelial growth factor receptor-1 (VEGFR-1, Flt-1), of downstream VEGF effectors matrix-metalloproteinase-1 (MMP-1) and connective tissue growth factor (CTGF), and of VEGF-interacting antiangiogenic thrombospondin-1 and -independent angiostatin in brains of patients who died with CM and controls by immunohistochemistry and Western blotting experiments. Most prominently, we detected more VEGF(+) astrocytes in CM patients and deposition of Flt-1 in Dürck's granulomas. MMP-1 and thrombospondin-1 accumulated in macrophages/microglial cells in Dürck's granulomas. In one CM patient, massive amounts of CTGF were detected as perivascular paracellular deposits. Angiostatin was observed in the serum of 2/7 control but in no CM patients. These data demonstrate the activation of the proangiogenic VEGF signaling cascade in patients with CM, probably reflecting compensatory mechanisms of general and focal brain hypoxia observed in these patients.

Expression of angiostatin using DNA-based semliki forest virus replicon.

Angiogenesis is recognized as a critical factor in the growth of tumor cells and plays a key role in the tumor metastasis. Recent studies for antiangiogenic substances are getting popular. The angiostatin, one of the antiangiogenic substances, leads to the increased apoptosis of the tumor cells by inhibiting the neovascularization of the tumor. The angiostatin was identified as the internal fragments of the plasminogen which has no antiangiogenic activity. By hydrolysis of the plasminogen, the angiostatin can be produced. In this study, we constructed the SFV-derived DNA vector by employing the cytomegalovirus immediate early enhancer/ promoter (CMV). This vector makes it possible to transfect the cells with DNA without the in vitro transcription process. The C-myc epitope and polyhistidine residue sequences were placed in downstream of the angiostatin gene to make it eligible to detect the expressed protein. The murine Ig k-chain V-J2-C signal sequence was placed in upstream to secrete the expressed protein from the cells. We confirmed the expression of angiostatin in the BHK-21 cells using DNA-based SFV replicon.

Expression of Angiostatin Using DNA-Based Semliki Forest Virus Replicon

Angiogenesis is recognized as a critical factor in the growth of tumor cells and plays a key role in the tumor metastasis. Recent studies for antiangiogenic substances are getting popular. The angiostatin, one of the antiangiogenic substances, leads to the increased apoptosis of the tumor cells by inhibiting the neovascularization of the tumor. The angiostatin was identified as the internal fragments of the plasminogen which has no antiangiogenic activity. By hydrolysis of the plasminogen, the angiostatin can be produced. In this study, we constructed the SFV-derived DNA vector by employing the cytomegalovirus immediate early enhancer/ promoter (CMV). This vector makes it possible to transfect the cells with DNA without the in vitro transcription process. The C-myc epitope and polyhistidine residue sequences were placed in downstream of the angiostatin gene to make it eligible to detect the expressed protein. The murine Ig kappa-chain V-J2-C signal sequence was placed in upstream to secrete the expressed protein from the cells. We confirmed the expression of angiostatin in the BHK-21 cells using DNA-based SFV replicon.