Serum endostatin predicts tumor vascularity in hepatocellular carcinoma

Heparan Sulfate in the Tumor Microenvironment

The biology of tumor cells strictly depends on their microenvironment architecture and composition, which controls the availability of growth factors and signaling molecules. Thus, the network of glycosaminoglycans, proteoglycans, and proteins known as extracellular matrix (ECM) that surrounds the cells plays a central role in the regulation of tumor fate. Heparan sulfate (HS) and heparan sulfate proteoglycans (HSPGs) are highly versatile ECM components that bind and regulate the activity of growth factors, cell membrane receptors, and other ECM molecules. These HS binding partners modulate cell adhesion, motility, and proliferation that are processes altered during tumor progression. Modification in the expression and activity of HS, HSPGs, and the respective metabolic enzymes results unavoidably in alteration of tumor cell microenvironment. In this light, the targeting of HS structure and metabolism is potentially a new tool in the treatment of different cancer types.

Exploring the roles of MACIT and multiplexin collagens in stem cells and cancer

The extracellular matrix (ECM) is ubiquitously involved in neoplastic transformation, tumour growth and metastatic dissemination, and the interplay between tumour and stromal cells and the ECM is now considered crucial for the formation of a tumour-supporting microenvironment. The 28 different collagens (Col) form a major ECM protein family and display extraordinary functional diversity in tissue homeostasis as well as in pathological conditions, with functions ranging from structural support for tissues to regulatory binding activities and storage of biologically active cryptic domains releasable through ECM proteolysis. Two subfamilies of collagens, namely the plasma membrane-associated collagens with interrupted triple-helices (MACITs, including ColXIII, ColXXIII and ColXXV) and the basement membrane-associated collagens with multiple triple-helix domains with interruptions (multiplexins, including ColXV and ColXVIII), have highly interesting regulatory functions in tissue and organ development, as well as in various diseases, including cancer. An increasing, albeit yet sparse, data suggest that these collagens play crucial roles in conveying regulatory signals from the extracellular space to cells. We summarize here the current knowledge about MACITs and multiplexins as regulators of stemness and oncogenic processes, as well as their roles in influencing cell fate decisions in healthy and cancerous tissues. In addition, we present a bioinformatic analysis of the impacts of MACITs and multiplexins transcript levels on the prognosis of patients representing a wide array of malignant diseases, to aid future diagnostic and therapeutic efforts.

Proteoglycans Are Attractive Biomarkers and Therapeutic Targets in Hepatocellular Carcinoma

Proteoglycans, which consist of a protein core and glycosaminoglycan chains, are major components of the extracellular matrix and play physiological roles in maintaining tissue homeostasis. In the carcinogenic tissue microenvironment, proteoglycan expression changes dramatically. Altered proteoglycan expression on tumor and stromal cells affects cancer cell signaling pathways, which alters growth, migration, and angiogenesis and could facilitate tumorigenesis. This dysregulation of proteoglycans has been implicated in the pathogenesis of diseases such as hepatocellular carcinoma (HCC) and the underlying mechanism has been studied extensively. This review summarizes the current knowledge of the roles of proteoglycans in the genesis and progression of HCC. It focuses on well-investigated proteoglycans such as serglycin, syndecan-1, glypican 3, agrin, collagen XVIII/endostatin, versican, and decorin, with particular emphasis on the potential of these factors as biomarkers and therapeutic targets in HCC regarding the future perspective of precision medicine toward the "cure of HCC".

Collagen XVIII in tissue homeostasis and dysregulation - Lessons learned from model organisms and human patients

Collagen XVIII is a ubiquitous basement membrane (BM) proteoglycan produced in three tissue-specific isoforms that differ in their N-terminal non-collagenous sequences, but share collagenous and C-terminal non-collagenous domains. The collagenous domain provides flexibility to the large collagen XVIII molecules on account of multiple interruptions in collagenous sequences. Each isoform has a complex multi-domain structure that endows it with an ability to perform various biological functions. The long isoform contains a frizzled-like (Fz) domain with Wnt-inhibiting activity and a unique domain of unknown function (DUF959), which is also present in the medium isoform. All three isoforms share an N-terminal laminin-G-like/thrombospondin-1 sequence whose specific functions still remain unconfirmed. The proteoglycan nature of the isoforms further increases the functional diversity of collagen XVIII. An anti-angiogenic domain termed endostatin resides in the C-terminus of collagen XVIII and is proteolytically cleaved from the parental molecule during the BM breakdown for example in the process of tumour progression. Recombinant endostatin can efficiently reduce tumour angiogenesis and growth in experimental models by inhibiting endothelial cell migration and proliferation or by inducing their death, but its efficacy against human cancers is still a subject of debate. Mutations in the COL18A1 gene result in Knobloch syndrome, a genetic disorder characterised mainly by severe eye defects and encephalocele and, occasionally, other symptoms. Studies with gene-modified mice have elucidated some aspects of this rare disease, highlighting in particular the importance of collagen XVIII in the development of the eye. Research with model organisms have also helped in determining other structural and biological functions of collagen XVIII, such as its requirement in the maintenance of BM integrity and its emerging roles in regulating cell survival, stem or progenitor cell maintenance and differentiation and inflammation. In this review, we summarise current knowledge on the properties and endogenous functions of collagen XVIII in normal situations and tissue dysregulation. When data is available, we discuss the functions of the distinct isoforms and their specific domains.

Plasmin releases the anti-tumor peptide from the NC1 domain of collagen XIX

During tumor invasion, tumor cells degrade the extracellular matrix. Basement membrane degradation is responsible for the production of peptides with anti-tumor properties. Type XIX collagen is associated with basement membranes in vascular, neuronal, mesenchymal and epithelial tissues. Previously, we demonstrated that the non-collagenous NC1, C-terminal, domain of collagen XIX [NC1(XIX)] inhibits the migration capacities of tumor cells and exerts a strong inhibition of tumor growth. Here, we demonstrate that plasmin, one of the most important enzyme involved in tumor invasion, was able to release a fragment of NC1(XIX), which retained the anti-tumor activity. Molecular modeling studies showed that NC1(XIX) and the anti-tumor fragment released by plasmin (F4) adopted locally the same type I β-turn conformation. This suggests that the anti-tumor effect is conformation-dependent. This study demonstrates that collagen XIX is a novel proteolytic substrate for plasmin. Such release may constitute a defense of the organism against tumor invasion.

A competitive enzyme-linked immunosorbent assay for quantification of tetrastatin in body fluids and tumor extracts

Basement membrane collagens or derived fragments are measured in biological fluids such as blood and urine of patients and appear to be useful for diagnosis, prognostication, or treatment monitoring as proposed for endostatin, a fragment of collagen XVIII, or tumstatin, a fragment of collagen IV. Tetrastatin, the NC1 alpha 4 collagen IV domain, was previously reported to inhibit tumor growth and angiogenesis. The aim of this study was to develop and validate a method to measure tetrastatin concentrations in human fluids. We developed a competitive enzyme-linked immunosorbent assay (ELISA). It allowed measuring tetrastatin levels in human serum, bronchial aspiration and bronchoalveolar lavage fluids, and lung tissue extracts. The tetrastatin level was significantly higher in tumor tissues than in healthy lung tissues. Tetrastatin competitive ELISA could be useful to quantify tetrastatin in tissues and biological fluids for the diagnosis or prognostication of diseases in which basement membrane metabolism may be altered, especially tumor progression.

Antiangiogenic strategies in hepatocellular carcinoma: current status

Hepatocellular carcinoma is a leading cause of cancer death worldwide in both adult and pediatric patients. Despite many options, no ideal treatment exists for this highly malignant tumor, and management strategies have varied accordingly. Angiogenesis, the formation of new blood vessels, is an essential component of hepatocellular carcinoma biology. Innovative approaches such as targeting the nontransformed, less resistant, tumor-supporting endothelial cells are currently under investigation in hepatocellular carcinoma. This review will focus on the current knowledge of the pathophysiology of hepatocellular carcinoma angiogenesis, as well as the reported data with angiogenesis inhibitors against hepatocellular carcinoma.

Serum levels of angiogenic and anti-angiogenic factors: their prognostic relevance in locally advanced hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a prototype tumor wherein angiogenesis plays a vital role in its progression. The role of VEGF, a major angiogenic factor in HCC is known; however, the role of anti-angiogenic factors simultaneously with the angiogenic factors has not been studied before. Hence, in this study, the serum levels of major angiogenic [Vascular Endothelial Growth Factor (VEGF), angiopoietin-2 (Ang-2)] and anti-angiogenic (endostatin, angiostatin) factors were analyzed and correlated with clinico-radiological features and with outcome. A total of 150 patients (50 HCC, 50 cirrhosis and 50 chronic hepatitis) and 50 healthy controls were enrolled in this study. Serum levels of VEGF, Ang-2, endostatin, and angiostatin were estimated by enzyme-linked immunosorbent assay. HCC shows significantly elevated serum levels of angiogenic factors VEGF and Ang-2 and of anti-angiogenic factors endostatin and angiostatin. ROC curve analysis for serum VEGF yielded an optimal cut-off value of 225.14 pg/ml, with a sensitivity of 78 % and specificity of 84.7 % for a diagnosis of HCC and its distinction from other group. Using this value, the univariate and multivariate analysis revealed significantly poor outcome in patients with higher levels of serum VEGF (p = 0.009). Combinatorial analysis revealed that patients with higher levels of both angiogenic and anti-angiogenic factors showed poor outcome. Serum VEGF correlates with poor survival of HCC patients and, therefore, serves as a non-invasive biomarker of poor prognosis. Moreover, elevated levels of anti-angiogenic factors occur endogenously in HCC patients.

Evaluation of endostatin and EGF serum levels in patients with gastric cancer

THE AIM OF THE STUDY was to assess angiogenesis markers - endostatin and endothelial growth factor (EGF) as markers of detection of gastric carcinoma. MATERIAL AND METHODS. The study involved 20 patients with colorectal cancer (10 women, 10 men) aged 35 - 75 years, mean age = 55 years ± 11.2 who referred to the 2nd Department of General Surgery, Medical University in Lublin between June 2008 and June 2009. The control group comprised 10 volunteers (6 women, 4 men) who underwent upper gastrointestinal (GI) endoscopy due to the reflux disease and in whom gastric cancer was not diagnosed. RESULTS. The mean endostatin concentration in controls was 5.21 ng/mL ± 1.37. Mean concentrations in patients with gastric cancer were higher than those in controls - 5.91 ng/mL ± 1.5. The difference was not statistically significant (p= 0.714). The EGF concentration in the control group was 28.19 pg/mL ± 12.94. EGF concentrations in patients with gastric cancer were higher compared to the control group - 28.8 pg/mL ± 12.63. The difference was not statistically significant (p= 0.85). The mean concentration of endostatin before the operation was 5.91 ng/mL ± 1.5 and after surgery was 5.33 ng/mL ± 2.01, the difference was not statistically significant. CONCLUSIONS. Blood endostatin and EGF quantitative determinations probably is not useful for detection of gastric carcinoma and effectiveness of treatment.

A 3' UTR SNP in COL18A1 is associated with susceptibility to HBV related hepatocellular carcinoma in Chinese: three independent case-control studies

Background

Accumulated evidences indicate that single nucleotide polymorphisms (SNP) in angiogenesis and tumorigenesis related genes are associated with risk of Hepatocellular carcinoma (HCC). COL18A1 encodes the precursor of endostatin, which is a broad-spectrum angiogenesis inhibitor, and we speculate that SNPs in COL18A1 may be associated with susceptibility to HCC.

Methods and Findings

We carried out a 2-stage association study in 3 independent case-control groups in a total of 1067 chronic hepatitis B (CHB) patients and 808 hepatitis B virus (HBV) related HCC patients in Han Chinese. Four SNPs which can represent all potential functional SNPs with MAF>0.1 recorded in HapMap database were genotyped using TaqMan methods. Levels of total COL18A1 mRNA were also examined using quantitative real-time RT-PCR. We found that rs7499 located in 3′-UTR to be strongly associated with HBV related HCC (P_combined = 0.0000005, OR = 0.72, 95%CI = 0.63–0.82). COL18A1 mRNA expression was significantly decreased as the disease progressed (P = 0.000026).

Conclusion

These findings indicate that COL18A1 rs7499 may contribute to the risk of HCC in Han Chinese.

Osteopontin and endostatin concentrations in peripheral blood of patients with adrenal tumors undergoing unilateral adrenalectomy

Peripheral blood osteopontin (OPN) and endostatin (END) levels were studied in 35 patients with adrenal cortex tumors and 10 patients with pheochromocytoma before unilateral adrenalectomy, as well as in 10 healthy subjects (controls). Thirty days after surgery, OPN and END were evaluated again in 16 patients with adrenal cortex tumors and 4 female patients with pheochromocytoma. Before surgery, OPN blood concentrations increased in the group of patients with adrenal cortex carcinomas as compared to controls (p < 0.001) and the group with Conn syndrome (p < 0.05); they did not change after surgery. Before adrenalectomy, OPN blood levels in pheochromocytoma patients were also lower than in Conn syndrome subjects (p < 0.05). After adrenalectomy, the normal concentrations of END decreased only in the group of patients with hormonally inactive cortical adenomas (p < 0.05). We were unable to demonstrate any relationships between removed tumor volumes and OPN or END blood levels.

Serial serum VEGF-A, angiopoietin-2, and endostatin measurements in cirrhotic patients with hepatocellular carcinoma treated by transcatheter arterial chemoembolization

Vascular endothelial growth factor (VEGF), angiopoietin-2, and endostatin have been reported to be related with angiogenesis of hepatocellular carcinoma (HCC). The potential feasibility of serial serum VEGF-A, angiopoietin-2, and endostatin measurements in cirrhotic patients with HCC treated by transcatheter arterial chemoembolization (TACE) was investigated. VEGF-A, angiopoietin-2, and endostatin serum level were determined by enzyme-linked immunosorbent assay 1 day before and 7 days after TACE in 40 patients. Then they were followed up for 3 months. The results showed that TACE could cause significant increase of VEGF-A (p < 0.01) and angiopoietin-2 (p = 0.01); whereas there was no significant change of endostatin (p > 0.1). Twenty-five patients with rapid growth of HCC within 3 months after TACE had higher proportion of American Joint Committee on Cancer HCC staging >II and higher increase of VEGF-A after TACE than 15 patients without rapid growth (all p < 0.05). Stepwise logistic regression analysis revealed that VEGF-A >16.7 pg/mL 7 days after TACE selected by receiver operating characteristic curve analysis (p < 0.05) was the only independent predictor for rapid growth of HCC (odds ratio 6.33, 95% confidence interval: upper 26, lower 1.54, p < 0.05; sensitivity 76%, specificity 66.7%, accuracy 72.5%, positive predictive level 79.2%, negative predictive level 62.5%, p < 0.01). In conclusion, significant increases of serum level VEGF-A and angiopoietin-2 after TACE have been demonstrated from this study. Therefore, serial VEGF-A level 1 day before and 7 days after TACE may be used to predict rapid HCC growth.

An evolutionary explanation for the perturbation of the dynamics of metastatic tumors induced by surgery and acute inflammation

Surgery has contributed to unveil a tumor behavior that is difficult to reconcile with the models of tumorigenesis based on gradualism. The postsurgical patterns of progression include unexpected features such as distant interactions and variable rhythms. The underlying evidence can be summarized as follows: (1) the resection of the primary tumor is able to accelerate the evolution of micrometastasis in early stages, and (2) the outcome is transiently opposed in advanced tumors. The objective of this paper is to give some insight into tumorigenesis and surgery-related effects, by applying the concepts of the evolutionary theory in those tumor behaviors that gompertzian and tissular-centered models are unable to explain. According to this view, tumors are the consequence of natural selection operating at the somatic level, which is the basic mechanism of tumorigenesis, notwithstanding the complementary role of the intrinsic constrictions of complex networks. A tumor is a complicated phenomenon that entails growth, evolution and development simultaneously. So, an evo-devo perspective can explain how and why tumor subclones are able to translate competition from a metabolic level into neoangiogenesis and the immune response. The paper proposes that distant interactions are an extension of the ecological events at the local level. This notion explains the evolutionary basis for tumor dormancy, and warns against the teleological view of tumorigenesis as a process directed towards the maximization of a concrete trait such as aggressiveness.

The molecular pathogenesis and clinical implications of hepatocellular carcinoma

The prognosis of hepatocellular carcinoma (HCC) is affected by tumoral factors and liver functions; therefore it is often difficult to select the appropriate therapeutic methods for HCC. Recently, two global phase III trials showed that sorafenib, which is a tyrosine kinase inhibitor, improved the prognosis of patients with advanced HCC. As a new therapeutic strategy for HCC, sorafenib is expected to expand the indication for HCC in the future. However, it alone is insufficient for the molecular-targeted treatment of HCC because the signaling pathway exists not only in cancer cells but also in normal cells. Recently, cancer stem cells (CSCs) have attracted attention as a novel therapeutic target for HCC. There is now much evidence that stem cell properties such as self-renewal, unlimited proliferation, and differentiation are highly relevant to cancer recurrence and the drug resistance of HCC. In this review, we describe the molecular pathogenesis and the current state and future development of molecular- and CSC-therapeutic targeted agents for HCC, citing various reports.

Clinical significance of serum vascular endothelial growth factor, endostatin, and leptin levels in children with lymphoma

BACKGROUND

A number of clinical studies conducted in adults have demonstrated the prognostic significance of angiogenic factors in malignancies, however, only a limited number of studies have been conducted in children. The aim of this study was to determine serum vascular endothelial growth factor (VEGF), endostatin, and leptin levels in children with lymphoma and to investigate whether these factors provide prognostic information.

PROCEDURE

Serum samples from 36 children with lymphoma (non-Hodgkin lymphoma (NHL) N = 21, Hodgkin lymphoma (HL) N = 15) were collected at diagnosis and during remission. Serum samples were also collected from 18 healthy children as the control group. Serum VEGF and endostatin levels were quantified by using enzyme-linked immunosorbent assay (ELISA) and serum leptin by immunoradiometric assay.

RESULTS

The serum VEGF levels were found elevated in patients compared to controls (P = 0.033), while endostatin and leptin levels were lower in patients than in controls (endostatin, 43.9 ± 5.8 ng/ml vs. 123.6 ± 13.5 ng/ml, P < 0.001; leptin, 5 ± 1.5 ng/ml vs. 6.7 ± 1.2 ng/ml, P = 0.013). VEGF levels declined (pre, 151.6 ± 55.9 pg/ml vs. post, 16.2 ± 7.9 pg/ml, P = 0.041), while endostatin and leptin levels increased in patients who achieved remission (33 of 36 patients) when compared to pre-treatment levels (endostatin pre, 43.1 ± 5.9 ng/ml vs. post, 65.9 ± 6.8 ng/ml, P = 0.047; leptin, pre, 5.3 ± 1.6 ng/ml vs. post, 9.8 ± 2.7 ng/ml, P = 0.012). Serum VEGF, endostatin, and leptin levels were not predictive of survival.

CONCLUSION

Serial measurement of serum VEGF, endostatin, and leptin levels could potentially be used to predict response to treatment or progressive disease in children with lymphoma.

Development of sunitinib in hepatocellular carcinoma: rationale, early clinical experience, and correlative studies

The approval of a multitargeted receptor tyrosine kinase inhibitor, sorafenib, with activity against vascular endothelial growth factor receptor-2 and -3, Raf-1 and B-Raf, platelet-derived growth factor receptor-alpha and -beta, and other kinases, has ushered in the era of molecular targeted agents in advanced hepatocellular carcinoma (HCC). Sunitinib malate is an oral, multitargeted inhibitor of vascular endothelial growth factor receptor-1, -2, and -3, platelet-derived growth factor receptor-alpha and -beta, and other kinases implicated in tumor growth, angiogenesis, and metastasis. Sunitinib has been approved in metastatic renal cell carcinoma and gastrointestinal stromal tumor and is undergoing active clinical development in HCC. Early evidence of antitumor activity and a promising safety profile for this agent have emerged from single arm phase II trials in United States, European, and Asian patients with advanced HCC. Correlative studies of imaging and circulating biomarkers have provided insights into the potential mechanism of action of sunitinib. Additional phase II studies using either single agent or in combination with chemotherapeutic agents are ongoing, and a phase III trial comparing sunitinib and sorafenib in advanced HCC is actively accruing patients. Here, we review the current progress and future directions for the development of sunitinib in advanced HCC.

Molecular targeted therapy for advanced hepatocellular carcinoma: current status and future perspectives

Sorafenib, a multikinase inhibitor targeting vascular endothelial growth factor (VEGF)-mediated angiogenesis, is the first drug found to prolong survival of patients with advanced hepatocellular carcinoma (HCC). This advance has shifted the paradigm of systemic treatment for HCC toward molecular targeted therapy (MTT). However, the disease-stabilizing effect of VEGF signaling-targeted MTT normally lasts only for a few months, suggesting a rapid emergence of resistance in the majority of patients. To overcome the resistance to VEGF signaling-targeted MTT, strategies incorporating inhibition of either compensatory pro-angiogenic pathways or recruitment of bone marrow-derived circulating endothelial progenitors, as well as suppression of other oncogenic pathways, are currently being investigated. The combination of multiple molecular targeted agents or the use of multi-target agents may enhance the efficacy at the expense of increased toxicities. To facilitate the development of MTT for HCC, current methodologies for pharmacodynamic assessment, patient selection and target identification need to be improved. Patient selection according to the individual molecular signature of the tumor and correlative biomarker studies are encouraged while planning a clinical trial of novel MTT.

Serum Endostatin Levels and Regenerative Capacities of Normal and Cirrhotic Livers Following Partial Hepatectomy in Mice: The Response to Different Resection Sizes

BACKGROUND

Angiogenesis has an important role in liver regeneration. Antiangiogenic response in remnant liver following resection and its relationship to regeneration is not well known. The aim of this study was to investigate the effect of hepatectomy size on serum endostatin levels, and the effect of endostatin levels to liver regeneration after partial hepatectomy in normal and cirrhotic mice.

MATERIALS AND METHODS

Sixty noncirrhotic and 36 carbon tetrachloride-induced cirrhotic mice were included in the study. Noncirrhotic mice were randomly divided into four main groups: sham, 20%, 40%, and 70% hepatectomy groups. Similarly, cirrhotic mice were randomly divided into three main groups: sham, 20%, and 40% hepatectomy groups. The mice in each group were further divided into two subgroups to compare serum endostatin levels and liver regeneration indexes on days 1 and 14. Liver regeneration was evaluated by the proliferating cell nuclear antigen-labeling index. Serum endostatin level was measured to evaluate antiangiogenic response.

RESULTS

Serum endostatin levels on the first day and 14th day increased significantly in correlation with the hepatectomy size, both in normal mice and cirrhotic mice (P < 0.05). In normal mice with high regeneration indexes that underwent 40% and 70% hepatectomies, there was a significant increase in serum endostatin levels on the 14th day compared with the first day (P < 0.05). However, the increase in mice that underwent 20% hepatectomies was not significant. After 20% and 40% hepatectomies, first day serum endostatin levels were significantly higher in cirrhotic mice compared with normal mice (P < 0.05), which was independent of regeneration. Nevertheless, after 40% hepatectomies, 14th day serum endostatin levels were significantly lower in cirrhotic mice compared with normal mice, attributable to the limited regeneration capacity of cirrhotic liver (P < 0.05). Regeneration capacity of cirrhotic liver was low at all times.

CONCLUSIONS

The current study suggests that there is a significant relationship between serum endostatin levels and regeneration capacity after hepatectomy in normal mice. On the other hand, following resection of cirrhotic liver, regeneration capacity is depressed and high endostatin levels are independent of hepatic regeneration.

Serum endostatin and bFGF as predictive factors in advanced breast cancer patients treated with letrozole

INTRODUCTION

To investigate the value of baseline serum levels of VEGF, bFGF, endostatin and their ratio as predictive factors of response to endocrine therapy in patients with metastatic breast cancer (MBC) and positive ER treated with letrozole after tamoxifen failure.

MATERIALS AND METHOD

The serum levels of endostatin, VEGF and bFGF were determined in postmenopausal patients with progressing MBC from serum samples obtained before initiation of letrozole. The relation between serum angiogenic factor levels and TTP was investigated.

RESULTS

Seventy-six patients (45.2%) presented a high endostatin level (> 24.6 ng/ml), 40% low bFGF levels (0 pg/ml) and 50.4% low VEGF (=/< 187 ng/ml). With a median follow-up of 22 months, the median TTP was 12.3 months. Median TTP was worse in patients with high endostatin concentration as well as in the low bFGF group, but was not affected when VEGF was considered. When the two factors were combined, the median TTP of patients with endostatin > 24.6 ng/ml and bFGF equal 0 pg/ml was 9.5 months versus 19.5 months in patients with endostatin =/< 24.6 ng/ml and bFGF > 0 pg/ml.

CONCLUSIONS

The baseline levels of bFGF and endostatin are predictive factors of efficacy in patients with MBC treated with letrozole and can select groups with different TTP.

Angiogenesis and anti-angiogenesis in hepatocellular carcinoma

Experimental and clinical data indicate that in human hepatocellular carcinoma (HCC) tumor progression is associated with angiogenesis and that an increase in microvascular density is associated with a poor prognosis. This review summarizes the literature concerning the relationship between angiogenesis and progression in HCC. It is becoming increasingly evident that agents which interfere with blood vessel formation also block tumor progression. Accordingly, anti-angiogenic tumor therapy has gained much interest in preclinical and clinical assessments. The recent applications of anti-angiogenic agents which interfere or block HCC progression are reviewed.

Pericardial fluid and serum levels of vascular endothelial growth factor and endostatin in patients with or without coronary artery disease

BACKGROUND/PURPOSE

Vascular endothelial growth factor (VEGF) and endostatin are related to ischemic heart disease. This study investigated pericardial fluid and serum levels of VEGF and endostatin in patients with or without ischemic heart disease.

METHODS

A total of 39 patients (24 patients in the CAD group with significant coronary artery disease; 15 patients in the non-CAD group without coronary artery disease) undergoing open heart surgery were enrolled. In the CAD group, patients were classified according to good coronary collateralization (Group A; n = 11) or poor coronary collateralization (Group B; n = 13). Pericardial fluid and serum samples were obtained at the time of surgery. VEGF and endostatin were measured by enzyme-linked immunosorbent assay.

RESULTS

The levels of endostatin in both serum and pericardial fluid were significantly lower in the CAD group than in the non-CAD group (130.5 +/- 37.3 ng/mL vs. 172.4 +/- 37.8 ng/mL and 119.0 +/- 25.0 ng/mL vs. 143.0 +/- 23.5 ng/mL). The concentration of serum VEGF in the CAD group (92.6 +/- 18.2 pg/mL) was significantly higher than that in the non-CAD group (75.2 +/- 22.3 pg/mL). The concentration of serum VEGF in Group A (100.1 +/- 20.7 pg/mL) was significantly higher than that in Group B (84.3 +/- 12.4 pg/mL). The levels of pericardial fluid VEGF, serum and pericardial fluid endostatin were not significantly different between Groups A and B.

CONCLUSION

Patients with coronary artery disease have lower serum and pericardial fluid levels of endostatin and higher serum levels of VEGF. Serum level VEGF, but not endostatin, is associated with good or poor collateralization in patients with coronary artery disease.

Angiogenesis and antiangiogenic therapy in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is a hypervascular tumor characterized by neovascularization, which plays an important role in the growth and progression of HCC. Angiogenesis provides a target for novel prognostic and therapeutic approaches to HCC. Assessment of microvessel density using immunohistochemical staining for specific endothelial cell markers such as CD34 has been shown to provide prognostic information independent of conventional pathological parameters in HCC patients. Recent studies have unveiled the important angiogenic factors involved in the regulation of angiogenesis in HCC, although the exact molecular pathways are far from clear. Current data suggest that vascular endothelial growth factor (VEGF) plays a critical role in angiogenesis of HCC. Tumor expression of VEGF has been shown to correlate with tumor invasiveness and prognosis in patients with HCC. VEGF is an important molecular target for antiangiogenic therapy. Studies in animal models have demonstrated the efficacy of antiangiogenic agents such as anti-VEGF antibody and antagonists of VEGF receptors in suppressing hepatocarcinogenesis and growth of HCC. Antiangiogenic therapy has already entered clinical trials in HCC patients and holds the promise of providing an effective novel treatment for HCC, which is of great clinical significance because there is no existing effective systemic therapy for HCC.

Mutations in collagen 18A1 (COL18A1) and their relevance to the human phenotype

Collagen XVIII, a proteoglycan, is a component of basement membranes (BMs). There are three distinct isoforms that differ only by their N-terminal, but with a specific pattern of tissue and developmental expression. Cleavage of its C-terminal produces endostatin, an inhibitor of angiogenesis. In its N-terminal, there is a frizzled motif which seems to be involved in Wnt signaling. Mutations in this gene cause Knobloch syndrome KS), an autosomal recessive disorder characterized by vitreoretinal and macular degeneration and occipital encephalocele. This review discusses the effect of both rare and polymorphic alleles in the human phenotype, showing that deficiency of one of the collagen XVIII isoforms is sufficient to cause KS and that null alleles causing deficiency of all collagen XVIII isoforms are associated with a more severe ocular defect. This review besides illustrating the functional importance of collagen XVIII in eye development and its structure maintenance throughout life, it also shows its role in other tissues and organs, such as nervous system and kidney.

Inhibitory effect of adeno-associated virus-mediated gene transfer of human endostatin on hepatocellular carcinoma

AIM

To investigate the effect of adeno-associated virus-mediated gene transfer of human endostatin on the growth of hepatocellular carcinoma (HCC).

METHODS

HCC cell line Hep3B was infected with recombinant adeno-associated virus containing human endostatin gene (rAAV2-hEndo). The results of transfection were detected by RT-PCR and SDS-PAGE assay. MTT assay was used to observe the effects of supernatant of transfected cells on ECV304 cell proliferation. An animal model of HCC was established by injecting Hep3B cells subcutaneously into the back of nude mice. Intratumoral injection of rAAV2-hEndo, empty virus and phosphate-buffered saline were given sequentially. Serum endostatin was determined by ELISA, the inhibitory effect of endostatin on the growth of xenograft was assessed in 3 wk.

RESULTS

The results of RT-PCR and SDS-PAGE assay confirmed that rAAV2-hEndo successfully transfected Hep3B cells, and endostatin was secreted from Hep3B cells to medium. The supernatant of transfected cells markedly inhibited the proliferation of ECV304 cells (P<0.01). Intratumoral injection of rAAV2-hEndo (2 x 10(10) v.g.) led to a sustained serum endostatin level of approximately (86.71+/-5.19) ng/mL. The tumor volume and microvessel density were less in rAAV2-hEndo group than in control groups (P<0.01).

CONCLUSION

Human endostatin can be stably expressed by adeno-associated virus-mediated gene transfer and effectively inhibit the growth of HCC.

Role of serum vascular endothelial growth factor in the prediction of angiogenesis and prognosis for non-small cell lung cancer

Although vascular endothelial growth factor (VEGF) and matrix metalloproteinase (MMP)-9 are involved in angiogenesis of various cancers, clinical utility of preoperative serum concentration of these molecules in non-small cell lung cancer (NSCLC) has not yet been elucidated. In this study, we determined the concentration of VEGF, MMP-9 and various other tumor markers in serum prior to surgery and evaluated the results compared with intratumoral vasculature to isolate a valuable marker in determining the prediction of angiogenesis in NSCLC. Among these molecules and serum tumor markers, circulating serum VEGF was identified to markedly correlate with microvessel density (MVD) of the resected tumor specimens. Moreover, overall survival of patients with low VEGF levels (< or =326 ng/ml) was significantly greater than that of patients with high VEGF levels (>326 ng/ml), while patients with low MMP-9 levels (< or =189 ng/ml) and those with high MMP-9 levels (>189 ng/ml) revealed similar overall survival. Conclusively, preoperative concentration of serum VEGF may be the most valuable marker in the prediction of intratumoral angiogenesis and prognosis of patients with NSCLC.

Regulation of Tumor Angiogenesis by Fastatin, the Fourth FAS1 Domain of βig-h3, via αvβ3 Integrin

We previously reported that the FAS1 domains of betaig-h3 bear motifs that mediate endothelial cell adhesion and migration via interactions with alphavbeta3 integrin and regulate angiogenesis. In the present study, we show that the fourth FAS1 domain, designated fastatin, inhibits endothelial adhesion and migration, not only to betaig-h3, but also fibronectin and vitronectin, in a RGD-dependent manner. Fastatin and other FAS1 domains suppress endothelial cell tube formation and in vivo neovascularization in a Matrigel plug assay. The antiangiogenic activity of fastatin is associated with antitumor activity in mouse tumor models. Fastatin additionally induces apoptosis in several cells expressing alphavbeta3 integrin, including endothelial cells. Binding of fastatin to alphavbeta3 integrin inhibits phosphorylation of focal adhesion kinase, Raf, extracellular signal-regulated kinase, Akt, and mammalian target of rapamycin. Fastatin is thus the first endogenous angiogenesis regulator identified that inhibits both endothelial cell migration and growth by binding to alphavbeta3 integrin. Our data suggest that FAS1 domains from all possible forms of the four human FAS1 family proteins are potential endogenous regulators for pathologic angiogenesis. Moreover, FAS1 domains such as fastatin may be developed into drugs for blocking tumor angiogenesis.

Increased endostatin/collagen XVIII expression correlates with elevated VEGF level and poor prognosis in hepatocellular carcinoma

Liver is the primary source for collagen XVIII, the precursor of angiogenesis inhibitor, endostatin. However, the role of endostatin/collagen XVIII expression during liver carcinogenesis remains elusive. Therefore, we studied its expression in five hepatoma cell lines and 105 hepatocellular carcinoma specimens. The poorly differentiated hepatoma cell lines exhibited increased endostatin/collagen XVIII levels compared with the well-differentiated ones. In hepatoma tissues, endostatin/collagen XVIII expression was detected in various types of liver cells and was significantly stronger in adjacent nontumor tissues than that in tumors (P<0.001). Endostatin/collagen XVIII expression in nontumor tissues correlated with tumor stages (P=0.014) and expression of vascular endothelial growth factor (P=0.007), but not the stages of hepatic fibrosis (P>0.05). Kaplan-Meier analysis showed that patients with higher endostatin/collagen XVIII expression had significantly shorter overall survival (P=0.011) and disease-free survival (P=0.0034). Moreover, endostatin/collagen XVIII level was an independent prognostic factor for tumor recurrence (P=0.034) by multivariate analysis. In conclusion, increased endostatin/collagen XVIII expression correlated with hepatoma progression and predicted poor prognosis for patients with hepatocellular carcinoma.

Altered expression of vascular endothelial growth factor, fibroblast growth factor-2 and endostatin in patients with hepatocellular carcinoma

BACKGROUND

Advanced hepatocellular carcinoma (HCC) in humans is characterized by hypervascularity. In the present study, the expressions of vascular endothelial growth factor (VEGF), basic fibroblast growth factor (FGF-2) and endostatin were analyzed in patients with chronic liver disease to clarify the effect of these major angiogenic factors.

METHODS

Serum concentrations of VEGF, FGF-2 and endostatin in 24 patients with HCC, 16 patients with liver cirrhosis (LC) and 13 healthy volunteers were measured by enzyme-linked immunosorbent assay. The expression of VEGF in 21 surgically resected HCC samples was analyzed by immunohistochemistry, and that of VEGF isoforms in 15 HCC samples was assessed by reverse transcriptase-polymerase chain reaction (RT-PCR).

RESULTS

Serum VEGF, FGF-2 and endostatin concentrations were significantly elevated in patients with HCC compared with healthy volunteers; but there was no significant difference between patients with HCC and those with non-HCC liver disease. Immunohistochemical analysis showed that VEGF protein was strongly expressed in both well-differentiated HCC cells and non-cancerous hepatocytes, whereas in moderately and poorly differentiated HCC the expression was stronger in the endothelial cells (EC) lining intratumor vessels than in the cancer cells. On RT-PCR for VEGF isoforms it was found that VEGF-121, VEGF-165 and VEGF-189 were expressed in all but one of the HCC samples and in all corresponding non-HCC samples.

CONCLUSIONS

The results suggest that VEGF, FGF-2, and endostatin concentrations are elevated prior to the emergence of HCC and that the distribution of VEGF changes dynamically during the development of HCC.

Combined endostatin/sFlt-1 antiangiogenic gene therapy is highly effective in a rat model of HCC

Hepatocellular carcinoma (HCC) is regarded as a suitable target for antiangiogenic strategies. However, antiangiogenic agents aimed at single targets can be neutralized by upregulation of other proangiogenic factors. Therefore, combined approaches addressing at least two angiogenic targets should be more effective. Employing an appropriate rat hepatoma model, we examined the effects of sFlt-1 (soluble vascular endothelial growth factor [VEGF] receptor 1 as an indirect inhibitor of angiogenesis) and endostatin (a direct inhibitor of angiogenesis) in both single-agent as well as combined approaches under in vitro and in vivo conditions. Similar to human HCC, rat Morris hepatoma (MH) cells secreted high levels of VEGF, but no endogenous sFlt-1. Parental MH or MHES(r) cells, stably expressing rat endostatin, were adenovirally transduced either with AdsFlt-1 (encoding sFlt-1) or control vector Adnull (containing no transgene), followed by subcutaneous inoculation into syngeneic ACI rats. Compared with MH/Adnull cells, expressing no antiangiogenic factors at all, tumor weights were reduced fourfold in the MHES(r)/Adnull group, 19-fold in the MH/AdsFlt-1-group, and 77-fold in the MHES(r)/AdsFlt-1 combination therapy group. Analysis of variance did not show a significant interaction between the effects of the two factors ES(r) and sFlt-1; their effects multiplied. In conclusion, combined expression of sFlt-1 and endostatin effectively suppresses HCC growth under in vivo conditions. Supplementary material for this article can be found on the HEPATOLOGY website (http://interscience.wiley.com/jpages/0270-9139/suppmat/index.html).

The possible role of matrix metalloproteinase (MMP)-2 and MMP-9 in cancer, e.g. acute leukemia

In the past decades, a lot of effort has been put in identifying the role of matrix metalloproteinases (MMPs) in cancer. The main role of MMPs in angiogenesis, tumor growth and metastasis is degradation of extracellular matrix (ECM) and release and/or activation of growth factors through their degradative activity. The degradative activity finally results in cancer progression. MMP-inhibitors (MMPIs) have already been designed and tested, based on the degradative role of MMPs in cancer progression. First clinical trials with MMPIs have been performed with disappointing results, showing that in order to use MMP-inhibition the mechanisms underlying MMP-expression in cancer have to be further elucidated. This paper reviews the mechanisms of MMPs on molecular and cellular level and discusses the role for MMPs and MMP-inhibition in cancer with special focus on acute leukemia.

Prognostic significance of serum vascular endothelial growth factor and endostatin in patients with hepatocellular carcinoma

BACKGROUND

Vascular endothelial growth factor (VEGF) and endostatin stimulate and inhibit tumour angiogenesis respectively. Recent studies have demonstrated the prognostic value of serum levels of both VEGF and endostatin in patients with various types of cancer. Their significance in patients with hepatocellular carcinoma (HCC) remains unclear.

METHODS

Serum VEGF and endostatin levels were measured by enzyme immunoassay in 108 patients with HCC before surgical resection and in 20 healthy controls. Preoperative serum VEGF and endostatin levels were correlated with clinicopathological features and long-term survival.

RESULTS

Serum VEGF levels in patients with HCC were significantly higher than those in controls, but serum levels of endostatin were similar in the two groups. High serum levels of VEGF, but not endostatin, were significantly associated with venous invasion and advanced tumour stage. Patients with a serum VEGF level higher than median (over 245.0 pg/ml) had significantly worse overall and disease-free survival than those with a lower level (P = 0.012 and P = 0.022 respectively). On multivariate analysis, serum VEGF level was an independent prognostic factor (hazard ratio 1.86 (95 per cent confidence interval 1.10 to 3.92); P = 0.032). Serum endostatin levels did not have significant prognostic influence on overall or disease-free survival.

CONCLUSION

A high serum level of VEGF is a predictor of poor outcome after resection of HCC. Serum VEGF, but not endostatin, may be a useful prognostic marker in patients with HCC.

Overexpression of Collagen XVIII Is Associated with Poor Outcome and Elevated Levels of Circulating Serum Endostatin in Non–Small Cell Lung Cancer

PURPOSE

The aim of this study was to determine whether collagen XVIII expression is correlated with circulating serum endostatin and whether this has any prognostic value in patients with non-small cell lung cancer (NSCLC).

EXPERIMENTAL DESIGN

Serum endostatin levels were measured quantitatively by a competitive enzyme immunoassay, and collagen XVIII expression in tumor tissue was investigated with an immunohistochemical method in a series of 94 patients who underwent surgery for NSCLC.

RESULTS

Sixty cases (63.8%) had positive immunohistochemical staining with anticollagen XVIII polyclonal antibodies, including strongly positive staining in 11 (11.7%) cases. The mean (+/- SD) serum endostatin level was 41.6 +/- 34.4 ng/ml in the patient group and 16.3 +/- 10.3 ng/ml in the control group (P < 0.0001). The 11 cases who were strongly collagen XVIII-positive had significantly higher serum endostatin levels than the cases who were negative or weakly positive (P = 0.0297). The 5-year survival rates of negative, weakly positive, and strongly positive patients were 77.8%, 56.9%, and 43.8%, respectively. The cases with strongly positive collagen XVIII expression had a significantly poorer outcome than cases with negative expression (P = 0.0027). A multivariate analysis with Cox proportional hazards model for disease-specific survival revealed that expression of collagen XVIII (strongly positive versus negative; weakly positive versus negative), tumor classification, and regional lymph node classification were independent prognostic factors.

CONCLUSIONS

Our results suggest that expression of collagen XVIII in tumor tissue is strongly associated with a poorer outcome in NSCLC and correlates with elevated levels of circulating serum endostatin.

Correlation between serum vascular endothelial growth factor and endostatin levels in patients with breast cancer

Serum vascular endothelial growth factor (VEGF) and endostatin levels were detected in 59 patients with breast cancer before surgery and at 3 weeks after surgery. Pre-operatively, their levels were significantly elevated and correlated with each other. Post-operatively, VEGF level decreased significantly and endostatin remained at a high level. Patients with both normalized VEGF and elevated endostatin following surgery had a lower risk of relapse than patients whose VEGF failed to normalize. Univariate and multivariate analyses showed a correlation between elevated VEGF level and short free-relapse survival. These findings suggest a new angiogenesis balance is formed in the patients after surgery and such a resultant balance may be beneficial for the prognosis of breast cancer, which deserves more extensive study.

Angiogenesis in hepatocellular carcinoma: the retrospectives and perspectives

Hepatocellular carcinoma (HCC) is a typical hypervascular tumor. Many angiogenic factors have been studied in HCC, and several anti-angiogenic therapies have been tested in animal models and patients. This paper summarizes the latest findings, especially regarding the clinical significance of endothelial cell markers and angiogenic factors in HCC, and experimental and clinical anti-angiogenesis therapies. Further developments in this area, such as endothelial cell-oriented research and better experimental and clinical designs in the evaluation of anti-angiogenic therapies are discussed.

Raised plasma endostatin levels correlate inversely with breast cancer angiogenesis

BACKGROUND

Angiogenesis is essential for solid tumors, such as breast cancer, to grow. The effect of surgical removal of breast tumors on plasma endostatin and vascular endothelial growth factor (VEGF) levels was evaluated. Tumor tissues were analyzed for expression of Intratumoral microvessel density (IMVD) and endostatin. The effect of VEGF and endostatin in inducing apoptosis on human liver microvascular endothelial cells (HLMVEC) was investigated.

MATERIALS AND METHODS

Plasma from healthy volunteers, patients with fibroadenomas and breast cancer patients were assayed for endostatin and VEGF via immunoassay, pre-operatively and four weeks post-operatively. Expression of endostatin in tumor tissue was determined by Western blotting. IMVD was assessed following immunohistochemical staining with anti-CD34 antibody.

RESULTS

Plasma endostatin levels, in breast cancer patients, were significantly elevated (P = 0.015) in the post-operative (60.59 +/- 7.70 etag/ml) compared with the pre-operative group (30.62 +/- 4.54 etag/ml) and with normal age-matched controls (34.97 +/- 3.76 etag/ml). In patients with high pre-operative plasma endostatin value, IMVD was decreased to 20.1 +/- 3.2 counts compared with 41.9 +/- 5.4 counts in those with low pre-operative endostatin value (P = 0.006). Neither plasma endostatin nor VEGF levels correlated with routine clinico-pathological parameters. Endostatin induced endothelial cell apoptosis and modulated the cytoprotective effect of VEGF in HLMVEC survival.

CONCLUSIONS

Plasma endostatin levels are increased in patients following surgical removal of the primary tumor. The decreased IMVD seen in patients with higher endostatin levels may be due to the apoptosis-inducing effect of endostatin on microvascular endothelial cells.