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

A narrative review of the effects of dexamethasone on traumatic brain injury in clinical and animal studies: focusing on inflammation

Traumatic brain injury (TBI) is a type of brain injury resulting from a sudden physical force to the head. TBI can range from mild, such as a concussion, to severe, which might result in long-term complications or even death. The initial impact or primary injury to the brain is followed by neuroinflammation, excitotoxicity, and oxidative stress, which are the hallmarks of the secondary injury phase, that can further damage the brain tissue. Dexamethasone (DXM) has neuroprotective effects. It reduces neuroinflammation, a critical factor in secondary injury-associated neuronal damage. DXM can also suppress the microglia activation and infiltrated macrophages, which are responsible for producing pro-inflammatory cytokines that contribute to neuroinflammation. Considering the outcomes of this research, some of the effects of DXM on TBI include: (1) DXM-loaded hydrogels reduce apoptosis, neuroinflammation, and lesion volume and improves neuronal cell survival and motor performance, (2) DXM treatment elevates the levels of Ndufs2, Gria3, MAOB, and Ndufv2 in the hippocampus following TBI, (3) DXM decreases the quantity of circulating endothelial progenitor cells, (4) DXM reduces the expression of IL1, (5) DXM suppresses the infiltration of RhoA + cells into primary lesions of TBI and (6) DXM treatment led to an increase in fractional anisotropy values and a decrease in apparent diffusion coefficient values, indicating improved white matter integrity. According to the study, the findings show that DXM treatment has neuroprotective effects in TBI. This indicates that DXM is a promising therapeutic approach to treating TBI.

Combination of Phenethyl Isothiocyanate and Dasatinib Inhibits Hepatocellular Carcinoma Metastatic Potential through FAK/STAT3/Cadherin Signalling and Reduction of VEGF Secretion

Cancerous cells are characterised by their ability to invade, metastasise, and induce angiogenesis. Tumour cells use various molecules that can be targeted to reverse these processes. Dasatinib, a potent Src inhibitor, has shown promising results in treating hepatocellular carcinoma (HCC) in vitro and in vivo. However, its effectiveness is limited by focal adhesion kinase (FAK) activation. Isothiocyanates, on the other hand, are phytochemicals with broad anticancer activity and FAK inhibition capabilities. This study evaluated the synergistic effect of dasatinib and phenethyl isothiocyanate (PEITC) on HCC. The combination was tested using various assays, including MTT, adhesion, scratch, Boyden chamber, chorioallantoic membrane (CAM), and yolk sac membrane (YSM) assays to evaluate the effect of the drug combination on HCC metastatic potential and angiogenesis in vitro and in vivo. The results showed that the combination inhibited the adhesion, migration, and invasion of HepG2 cells and reduced xenograft volume in the CAM assay. Additionally, the combination reduced angiogenesis in vitro, diminishing the growth of vessels in the tube formation assay. The inhibition of FAK/STAT3 signalling led to increased E-cadherin expression and reduced VEGF secretion, reducing HCC metastatic potential. Therefore, a combination of PEITC and dasatinib could be a potential therapeutic strategy for the treatment of HCC.

The extracellular matrix in hepatocellular carcinoma: Mechanisms and therapeutic vulnerability

The tumor microenvironment (TME) is influenced by a "disorganized" extracellular matrix (ECM) that sensitizes cancer cells toward mechanical stress, signaling, and structural alterations. In hepatocellular carcinoma (HCC), lack of knowledge about key ECM proteins driving the TME refractory to targeted therapies poses a barrier to the identification of new therapeutic targets. Herein, we discuss the contributions of various ECM components that impact hepatocytes and their surrounding support network during tumorigenesis. In addition, the underpinnings by which ECM proteins transduce mechanical signals to the liver TME are detailed. Finally, in view of the bidirectional feedback between the ECM, transformed hepatocytes, and immune cells, we highlight the potential role of the ECM disorganization process in shaping responses to immune checkpoint inhibitors and targeted therapies. Our comprehensive characterization of these ECM components may provide a roadmap for innovative therapeutic approaches to restrain HCC.

Cromolyn platform suppresses fibrosis and inflammation, promotes microglial phagocytosis and neurite outgrowth

Neurodegenerative diseases are characterized by chronic neuroinflammation and may perpetuate ongoing fibrotic reactions within the central nervous system. Unfortunately, there is no therapeutic available that treats neurodegenerative inflammation and its sequelae. Here we utilize cromolyn, a mast cell inhibitor with anti-inflammatory capabilities, and its fluorinated analogue F-cromolyn to study fibrosis-related protein regulation and secretion downstream of neuroinflammation and their ability to promote microglial phagocytosis and neurite outgrowth. In this report, RNA-seq analysis shows that administration of the pro-inflammatory cytokine TNF-α to HMC3 human microglia results in a robust upregulation of fibrosis-associated genes. Subsequent treatment with cromolyn and F-cromolyn resulted in reduced secretion of collagen XVIII, fibronectin, and tenascin-c. Additionally, we show that cromolyn and F-cromolyn reduce pro-inflammatory proteins PLP1, PELP1, HSP90, IL-2, GRO-α, Eotaxin, and VEGF-Α, while promoting secretion of anti-inflammatory IL-4 in HMC3 microglia. Furthermore, cromolyn and F-cromolyn augment neurite outgrowth in PC12 neuronal cells in concert with nerve growth factor. Treatment also differentially altered secretion of neurogenesis-related proteins TTL, PROX1, Rab35, and CSDE1 in HMC3 microglia. Finally, iPSC-derived human microglia more readily phagocytose Aβ42 with cromolyn and F-cromolyn relative to controls. We propose the cromolyn platform targets multiple proteins upstream of PI3K/Akt/mTOR, NF-κB, and GSK-3β signaling pathways to affect cytokine, chemokine, and fibrosis-related protein expression.

Endostatin in Renal and Cardiovascular Diseases

Endostatin, a protein derived from the cleavage of collagen XVIII by the action of proteases, is an endogenous inhibitor known for its ability to inhibit proliferation and migration of endothelial cells, angiogenesis, and tumor growth. Angiogenesis is defined as the formation of new blood vessels from pre-existing vasculature, which is crucial in many physiological processes, such as embryogenesis, tissue regeneration, and neoplasia.

SUMMARY

Increasing evidence shows that dysregulation of angiogenesis is crucial for the pathogenesis of renal and cardiovascular diseases. Endostatin plays a pivotal role in the regulation of angiogenesis. Recent studies have provided evidence that circulating endostatin increases significantly in patients with kidney and heart failure and may also contribute to disease progression.

KEY MESSAGE

In the current review, we summarize the latest findings on preclinical and clinical studies analyzing the impact of endostatin on renal and cardiovascular diseases.

NBAT1/CASC15-003/USP36 control MYCN expression and its downstream pathway genes in neuroblastoma

Background

MYCN has been an attractive therapeutic target in neuroblastoma considering the widespread amplification of the MYCN locus in neuroblastoma, and its established role in neuroblastoma development and progression. Thus, understanding neuroblastoma-specific control of MYCN expression at the transcriptional and post-transcriptional level would lead to identification of novel MYCN-dependent oncogenic pathways and potential therapeutic strategies.

Methods

By performing loss- and gain-of-function experiments of the neuroblastoma hotspot locus 6p22.3 derived lncRNAs CASC15-003 and NBAT1, together with coimmunoprecipitation and immunoblotting of MYCN, we have shown that both lncRNAs post-translationally control the expression of MYCN through regulating a deubiquitinase enzyme USP36. USP36 oncogenic properties were investigated using cancer cell lines and in vivo models. RNA-seq analysis of loss-of-function experiments of CASC15-003/NBAT1/MYCN/USP36 and JQ1-treated neuroblastoma cells uncovered MYCN-dependent oncogenic pathways.

Results

We show that NBAT1/CASC15-003 control the stability of MYCN protein through their common interacting protein partner USP36. USP36 harbors oncogenic properties and its higher expression in neuroblastoma patients correlates with poor prognosis, and its downregulation significantly reduces tumor growth in neuroblastoma cell lines and xenograft models. Unbiased integration of RNA-seq data from CASC15-003, NBAT1, USP36, and MYCN knockdowns and neuroblastoma cells treated with MYCN inhibitor JQ1, identified genes that are jointly regulated by the NBAT1/CASC15-003/USP36/MYCN pathway. Functional experiments on one of the target genes, COL18A1, revealed its role in the NBAT1/CASC15-003-dependent cell adhesion feature in neuroblastoma cells.

Conclusion

Our data show post-translational regulation of MYCN by NBAT1/CASC15-003/USP36, which represents a new regulatory layer in the complex multilayered gene regulatory network that controls MYCN expression.

Collagen biology making inroads into prognosis and treatment of cancer progression and metastasis

Progression through dissemination to tumor-surrounding tissues and metastasis development is a hallmark of cancer that requires continuous cell-to-cell interactions and tissue remodeling. In fact, metastization can be regarded as a tissue disease orchestrated by cancer cells, leading to neoplastic colonization of new organs. Collagen is a major component of the extracellular matrix (ECM), and increasing evidence suggests that it has an important role in cancer progression and metastasis. Desmoplasia and collagen biomarkers have been associated with relapse and death in cancer patients. Despite the increasing interest in ECM and in the desmoplastic process in tumor microenvironment as prognostic factors and therapeutic targets in cancer, further research is required for a better understanding of these aspects of cancer biology. In this review, published evidence correlating collagen with cancer prognosis is retrieved and analyzed, and the role of collagen and its fragments in cancer pathophysiology is discussed.

Roles of Proteoglycans and Glycosaminoglycans in Cancer Development and Progression

The extracellular matrix (ECM) spatiotemporally controls cell fate; however, dysregulation of ECM remodeling can lead to tumorigenesis and cancer development by providing favorable conditions for tumor cells. Proteoglycans (PGs) and glycosaminoglycans (GAGs) are the major macromolecules composing ECM. They influence both cell behavior and matrix properties through direct and indirect interactions with various cytokines, growth factors, cell surface receptors, adhesion molecules, enzymes, and glycoproteins within the ECM. The classical features of PGs/GAGs play well-known roles in cancer angiogenesis, proliferation, invasion, and metastasis. Several lines of evidence suggest that PGs/GAGs critically affect broader aspects in cancer initiation and the progression process, including regulation of cell metabolism, serving as a sensor of ECM's mechanical properties, affecting immune supervision, and participating in therapeutic resistance to various forms of treatment. These functions may be implemented through the characteristics of PGs/GAGs as molecular bridges linking ECM and cells in cell-specific and context-specific manners within the tumor microenvironment (TME). In this review, we intend to present a comprehensive illustration of the ways in which PGs/GAGs participate in and regulate several aspects of tumorigenesis; we put forward a perspective regarding their effects as biomarkers or targets for diagnoses and therapeutic interventions.

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.

Combined microwave ablation and antiangiogenic therapy to increase local efficacy

Purpose: We aim to evaluate the efficacy, safety and survival time of microwave ablation (MWA) with adjuvant antiangiogenic therapy-endostatin in animal models.Material and methods: A total of 40 rabbits successfully implanted with VX2 tumors were randomly assigned to four experimental groups: Group A underwent only microwave ablation of the tumors; Group B received only antiangiogenic drugs endostatin; Group C received endostatin immediately after MWA; Group D followed up without treatment.Results: Two months post-treatment, tumor sizes of Group A and Group C were reduced to 1.936 ± 0.373 cm³ and 1.592 ± 0.382 cm³, respectively. However, tumors grew to 15.091 ± 1.735 cm³ and 47.825 ± 7.664 cm³ in Group B and the control group. Three months post-treatment, tumor sizes in Group A and Group C maintained as 1.395 ± 0.394 cm³ and 1.482 ± 0.305 cm³, significantly smaller than Group B (35.277 ± 6.019 cm³). All animals in the control group died, while four (40%) survived in Group B (Endo Group). The numbers of survivals in Groups A and C were seven (70%) and eight (80%), respectively. The lowest metastasis rate (2/10, 20%) was observed in Group C (combination therapy).Conclusion: The combination of MWA and antiangiogenic therapy triggered a significant reduction in the growth rate and metastases of tumors and may potentially improve survivals.

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".

Proteoglycans remodeling in cancer: Underlying molecular mechanisms

Extracellular matrix is a highly dynamic macromolecular network. Proteoglycans are major components of extracellular matrix playing key roles in its structural organization and cell signaling contributing to the control of numerous normal and pathological processes. As multifunctional molecules, proteoglycans participate in various cell functions during morphogenesis, wound healing, inflammation and tumorigenesis. Their interactions with matrix effectors, cell surface receptors and enzymes enable them with unique properties. In malignancy, extensive remodeling of tumor stroma is associated with marked alterations in proteoglycans' expression and structural variability. Proteoglycans exert diverse functions in tumor stroma in a cell-specific and context-specific manner and they mainly contribute to the formation of a permissive provisional matrix for tumor growth affecting tissue organization, cell-cell and cell-matrix interactions and tumor cell signaling. Proteoglycans also modulate cancer cell phenotype and properties, the development of drug resistance and tumor stroma angiogenesis. This review summarizes the proteoglycans remodeling and their novel biological roles in malignancies with particular emphasis to the underlying molecular mechanisms.

Eupafolin Exhibits Potent Anti-Angiogenic and Antitumor Activity in Hepatocellular Carcinoma

Eupafolin is a flavonoid extracted from the common sage herb which has been used in China as traditional medicine. Previous studies had reported that eupafolin had antioxidative, anti-inflammatory and antitumor effects. However, the function and the mechanism of eupafolin to exert its antitumor activity, especially its effect on tumor angiogenesis, have not been elucidated. Herein, we showed that eupafolin significantly inhibited vascular endothelial growth factor (VEGF)-induced cell proliferation, migration and tube formation of human umbilical vascular endothelial cells (HUVECs) in a dose-dependent manner. Meanwhile, the new blood microvessels induced by VEGF in the matrigel plug were also substantially suppressed by eupafolin. The results of HCC xenograft experiments demonstrated eupafolin remarkably inhibited tumor growth and tumor angiogenesis in vivo, suggesting the antitumor activity exerted by eupafolin was closely correlated with its potency on tumor angiogenesis. Mechanism investigations revealed that eupafolin significantly blocked VEGF-induced activation of VEGFR2 in HUVEC cells as well as its downstream signaling pathway. In addition to the effect on endothelial cells, through inhibiting Akt activity in tumor cells, VEGF secretion in HepG2 was dramatically decreased after eupafolin treatment. Our study was the first to report the activity of eupafolin against tumor angiogenesis as well as the underlying mechanism by which eupafolin to exert its anti-angiogenic activity.

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.

Endostatin's emerging roles in angiogenesis, lymphangiogenesis, disease, and clinical applications

BACKGROUND

Angiogenesis is the process of neovascularization from pre-existing vasculature and is involved in various physiological and pathological processes. Inhibitors of angiogenesis, administered either as individual drugs or in combination with other chemotherapy, have been shown to benefit patients with various cancers. Endostatin, a 20-kDa C-terminal fragment of type XVIII collagen, is one of the most potent inhibitors of angiogenesis.

SCOPE OF REVIEW

We discuss the biology behind endostatin in the context of its endogenous production, the various receptors to which it binds, and the mechanisms by which it acts. We focus on its inhibitory role in angiogenesis, lymphangiogenesis, and cancer metastasis. We also present emerging clinical applications for endostatin and its potential as a therapeutic agent in the form a short peptide.

MAJOR CONCLUSIONS

The delicate balance between pro- and anti-angiogenic factors can be modulated to result in physiological wound healing or pathological tumor metastasis. Research in the last decade has emphasized an emerging clinical potential for endostatin as a biomarker and as a therapeutic short peptide. Moreover, elevated or depressed endostatin levels in diseased states may help explain the pathophysiological mechanisms of the particular disease.

GENERAL SIGNIFICANCE

Endostatin was once sought after as the 'be all and end all' for cancer treatment; however, research throughout the last decade has made it apparent that endostatin's effects are complex and involve multiple mechanisms. A better understanding of newly discovered mechanisms and clinical applications still has the potential to lead to future advances in the use of endostatin in the clinic.

Correlation of serum levels of endostatin with tumor stage in gastric cancer: a systematic review and meta-analysis

Background. We performed a systematic review and meta-analysis to study the association between serum endostatin levels and gastric cancer (GC) progression. Method. We searched the MEDLINE, Science Citation Index, Cochrane Library, PubMed, Embase, Current Contents Index, and several Chinese databases for published studies relevant to our study topic. Carefully selected studies were pooled and SMD and its corresponding 95% CI were calculated. Version 12.0 STATA software was used for statistical analysis. Results. Serum endostatin levels were analyzed in 12 case-control studies (736 GC patients and 350 controls). Significant differences in serum endostatin levels were observed between GC patients and the healthy controls (SMD = 1.418, 95% CI = 1.079~1.757, P < 0.001). Importantly, significantly lower levels of serum endostatin were found in I-II grade patients compared to those with III-IV grade tumors (P < 0.001). Further, higher serum endostatin levels were observed in the LN invasion-positive GC subjects in comparison with LN invasion-negative subjects (P < 0.001). Conclusion. Patients with GC exhibited elevated levels of serum endostatin than controls and its level showed a statistical correlation with the more aggressive type of GC, exhibiting invasion and LN metastasis. Thus, serum levels of endostatin being a useful prognostic biomarker for GC patients warrants further investigation.

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.

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.

Proteolytically Derived Endogenous Angioinhibitors Originating from the Extracellular Matrix

Angiogenesis, a neovascularization process induced from the existing parent blood vessels, is a prerequisite for many physiological and pathological conditions. Under physiological conditions it is regulated by a balance between endogenous angioinhibitors and angioactivators, and an imbalance between them would lead to pathological conditions such as cancer, age-related macular degeneration (AMD), diabetic retinopathy, cardiovascular diseases, etc. Several proteolytically generated endogenous molecules have been identified which exhibit angioinhibition and/or antitumor activities. These angioinhibitors interact with endothelial and tumor cells by binding to distinct integrins and initiate many of their intracellular signaling mechanisms regulating the cell survival and or apoptotic pathways. The present review will focus on the extracellular matrix derived angioinhibitors, and their mechanisms of actions that point to the clinical significance and therapeutic implications.

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.

Prognostic relevance of collagen XVIII expression in metastatic gastric carcinoma

Collagen XVIII is a component of vascular and epithelial basement membranes. The C-terminal fragment of the protein is termed endostatin, and is a potent inhibitor of angiogenesis. No reports on the clinical implications of collagen XVIII expression in human gastric cancer are currently available. Here, we investigate the clinical significance of collagen XVIII expression in gastric cancer. Seven gastric cancer cell lines were subjected to Western blotting. Collagen XVIII expression was examined in 118 gastric carcinoma tissues via immunohistochemistry. Western blotting revealed the presence of the 22-kDa collagen XVIII protein in four of seven gastric cancer cell lines. Immunohistochemistry detected collagen XVIII expression in the tumor cytoplasm in 115 of 118 gastric carcinoma patients (97%). No correlation was evident between collagen XVIII expression score and clinicopathologic findings when all patients were considered together. However, on subgroup analysis, 42 of 70 patients with distant metastasis were classified into low or moderate collagen XVIII expression groups, whereas the remaining 28 patients were grouped as showing high collagen XVIII expression. The prognosis for patients with high collagen XVIII-expressing gastric carcinoma was significantly worse than that for patients displaying low or moderate collagen XVIII expression (median survival time, 7.8 months vs. 18.3 months [log-rank, p = 0.01]; median time to progression, 3 months vs. 8 months [log-rank, p = 0.01]). High expression of collagen XVIII is associated with poor prognosis in patients with metastatic gastric carcinoma. Further studies on larger patient populations are warranted to validate the utility of collagen XVIII as a prognostic biomarker in gastric carcinoma.

Functionally conserved cis-regulatory elements of COL18A1 identified through zebrafish transgenesis

Type XVIII collagen is a component of basement membranes, and expressed prominently in the eye, blood vessels, liver, and the central nervous system. Homozygous mutations in COL18A1 lead to Knobloch Syndrome, characterized by ocular defects and occipital encephalocele. However, relatively little has been described on the role of type XVIII collagen in development, and nothing is known about the regulation of its tissue-specific expression pattern. We have used zebrafish transgenesis to identify and characterize cis-regulatory sequences controlling expression of the human gene. Candidate enhancers were selected from non-coding sequence associated with COL18A1 based on sequence conservation among mammals. Although these displayed no overt conservation with orthologous zebrafish sequences, four regions nonetheless acted as tissue-specific transcriptional enhancers in the zebrafish embryo, and together recapitulated the major aspects of col18a1 expression. Additional post-hoc computational analysis on positive enhancer sequences revealed alignments between mammalian and teleost sequences, which we hypothesize predict the corresponding zebrafish enhancers; for one of these, we demonstrate functional overlap with the orthologous human enhancer sequence. Our results provide important insight into the biological function and regulation of COL18A1, and point to additional sequences that may contribute to complex diseases involving COL18A1. More generally, we show that combining functional data with targeted analyses for phylogenetic conservation can reveal conserved cis-regulatory elements in the large number of cases where computational alignment alone falls short.

Correlation analysis of liver tumor-associated genes with liver regeneration

AIM: To study at transcriptional level the similarities and differences of the physiological and biochemical activities between liver tumor (LT) and regenerating liver cells.

METHODS: LT-associated genes and their expression changes in LT were obtained from databases and scientific articles, and their expression profiles in rat liver regeneration (LR) were detected using Rat Genome 230 2.0 array. Subsequently their expression changes in LT and LR were compared and analyzed.

RESULTS: One hundred and twenty one LT-associated genes were found to be LR-associated. Thirty four genes were up-regulated, and 14 genes were down-regulated in both LT and regenerating liver; 20 genes up-regulated in LT were down-regulated in regenerating liver; 21 up-regulated genes and 16 down-regulated genes in LT were up-regulated at some time points and down-regulated at others during LR.

CONCLUSION: Results suggested that apoptosis activity suppressed in LT was still active in regenerating liver, and there are lots of similarities and differences between the LT and regenerating liver at the aspects of cell growth, proliferation, differentiation, migration and angiogenesis.

Prognostic molecular markers in hepatocellular carcinoma: a systematic review

Hepatocellular carcinoma (HCC) is the fifth commonest malignancy worldwide and its incidence is rising. Surgery, including transplantation, remains the only potentially curative modality for HCC, yet recurrence rates are high and long-term survival poor. The ability to predict individual recurrence risk and subsequently prognosis would help guide surgical and chemotherapeutic treatment. As understanding of hepatocarcinogenesis has increased, the myriad of genetic and molecular events that drive the hepatocarcinogenic disease process, including angiogenesis, invasion and metastasis, have been identified. This systematic review examines the evidence from published manuscripts reporting the prognostic potential of molecular biomarkers in hepatocellular carcinoma. In summary, a number of molecular biomarkers with prognostic significance have been identified in hepatocellular carcinoma. Not only might these molecules allow more accurate prediction of prognosis for patients with HCC, but they may also provide targets for potential therapeutic agents.

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.

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.

Pretreatment serum endostatin as a prognostic indicator in metastatic gastric carcinoma

Endostatin is the C-terminal antiangiogenic fragment of the extracellular matrix protein collagen XVIII, and is generated by tumor-derived proteases. The presence of serum endostatin in patients with gastric cancer has not been reported. The authors assessed the serum levels of endostatin in patients with gastric carcinoma and evaluated their association with the levels of vascular endothelial growth factor (VEGF) and the clinical outcome. A total of 107 patients with gastric cancer were included in the study. Pretherapeutic serum levels of endostatin and VEGF were measured using an ELISA, and compared with those in 23 healthy controls. The serum levels of endostatin and VEGF were higher in gastric cancer patients than in healthy controls (endostatin, 70.1 +/- 16.6 vs. 52.2 +/- 6.2 ng/mL [p < 0.001]; VEGF, 55.1 +/- 7.6 vs. 32.1 +/- 2.4 ng/mL [p < 0.001]; mean +/- SD). Serum endostatin levels were significantly associated with the presence of distant metastases (r = 0.556, p < 0.001) and VEGF levels (r = 0.335, p < 0.001), but not with the depth of tumor invasion, differentiation, or regional lymph node status. A serum endostatin level above the 75th percentile of the distribution for the patients (79.2 ng/mL) was associated with a poor outcome (last follow-up at 42 months; median survival time, 9 vs. 20 months [log-rank, p = 0.017]; median time to progression, 5 vs. 10 months [log-rank, p = 0.022]) in the patients with metastatic gastric cancer. The results suggest for the first time that an elevated serum level of endostatin at the diagnosis of metastatic gastric cancer could be predictive of a poor outcome.

Fusion expression and purification of human endostatin gene and its activity analysis

AIM: To procure human endostatin fusion protein with biological activity.

METHODS: The total RNA was extracted from fetal liver and amplified to acquire human endostatin gene by reverse transcription polymerase chain reaction (RT-PCR). Then the obtained gene was cloned into expression vector pTRX and transformed into E.coli BL21 (DE3). Endostatin was expressed in the E.coli by IPTG inducement, and then purified. MTT assay was used to detect the inhibitory activity of endostatin on human umbilical vein endothelial cells (ECV304).

RESULTS: One band with a length of 573 bp was showed after electrophoresis of RT-PCR product. After the obtained gene was transformed into E.coli DH5a, the positive clone was identified by KpnI and NotI digestion and its sequence was identified by sequencing. The pTRX-endo expression vector was successfully constructed and expressed in E.coli BL21 (DE3). SDS-PAGE analysis showed that the expressed endostatin was the right one. It had good biological activity after purification. The growth of ECV304 cells was markedly inhibited by endostatin in a dose-dependent manner, and ED50 was 550 μg/L.

CONCLUSION: Human endostatin gene is successfully expressed in the prokaryotic expressing vector pTRX, and human endostatin protein can inhibit the proliferation of ECV 304 cells.