Tumor progression-dependent angiogenesis in gastric cancer and its potential application

Despite improvements in the early diagnosis,prognosis and therapeutic strategies for gastric cancer(GC),human GC remains one of the most frequently diagnosed malignant tumors in the world,and the survival rate of GC patients remains very poor.Thus,a suitable therapeutic strategy for GC is important for prolonging survival.Both tumor cells themselves and the tumor microenvironment play an important role in tumorigenesis,including angiogenesis,inflammation,immunosuppression and metastasis.Importantly,these cells contribute to gastric carcinogenesis by altering the angiogenic phenotype switch.The development,relapse and spreading of tumors depend on new vessels that provide the nutrition,growth factors and oxygen required for continuous tumor growth.Therefore,a state of tumor dormancy could be induced by blocking tumor-associated angiogenesis.Recently,several antiangiogenic agents have been identified,and their potential for the clinical management of GC has been tested.Here,we provide an up-to-date summary of angiogenesis and the angiogenic factors associated with tumor progression in GC.We also review antiangiogenic agents with a focus on the anti-vascular endothelial growth factor receptor(VEGFR)-mediated pathway for endothelial cell growth and their angiogenesis ability in GC.However,most antiangiogenic agents have reported no benefit to overall survival(OS)compared to chemotherapy alone in local or advanced GC.In phase III clinical trials,only ramucirumab(anti-VEGFR blocker)and apatinib(VEGFR-TKI blocker)have reported an improved median overall response rate and prolonged OS and progression-free survival outcomes as a 2 nd-line agent combined with chemotherapy treatment in advanced GC.By providing insights into the molecular mechanisms of angiogenesis associated with tumor progression in GC,this review will hopefully aid the optimization of antiangiogenesis strategies for GC therapy in combination with chemotherapy and adjuvant treatment.

Roles of sphingosine-1-phosphate signaling in angiogenesis

Sphingosine-1-phosphate (S1P) is a blood-borne lipid mediator with pleiotropic biological activities. S1P acts via the specific cell surface G-protein-coupled receptors, S1P1-5. S1P1 and S1P2 were originally identified from vascular endothelial cells (ECs) and smooth muscle cells, respectively. Emerging evidence shows that S1P plays crucial roles in the regulation of vascular functions, including vascular formation, barrier protection and vascular tone via S1P1, S1P2 and S1P3. In particular, S1P regulates vascular formation through multiple mechanisms; S1P exerts both positive and negative effects on angiogenesis and vascular maturation. The positive and negative effects of S1P are mediated by S1P1 and S1P2, respectively. These effects of S1P1 and S1P2 are probably mediated by the S1P receptors expressed in multiple cell types including ECs and bone-marrow-derived cells. The receptor-subtype-specific, distinct effects ofS1P favor the development of novel therapeutic tactics for antitumor angiogenesis in cancer and therapeutic angiogenesis in ischemic diseases.

Growth factors for therapeutic angiogenesis in hypercholesterolemic erectile dysfunction

The past decade has seen an explosion of new information on the physiology of penile erection, and pathophysiology of erectile dysfunction （ED）. Hypercholesterolemia is a chronic condition that can lead to degeneration in the vasculature bed and can result in ED if the penile vasculature is involved. Angiogenesis is the growth of new blood vessels from preexisting vasculature. Therapeutic angiogenesis seeks to harness the mechanisms of vascular growth to treat disorders of inadequate tissue perfusion, such as coronary artery disease and ED. There have been tremendous changes in the field of therapeutic angiogenesis over the past decade, and there is much promise for the future. Initial preclinical work with cytokine growth factor delivery resulted in a great deal of enthusiasm for the treatment of ischemic heart and/or peripheral vascular disease, though clinical studies have not achieved similar success. With an increased understanding of the complex mechanisms involved in angiogenesis, novel therapies which target multiple different angiogenic pathways are also being developed and tested. The penis is a convenient tissue target for gene therapy because of its external location and accessibility, the ubiquity of endothelial lined spaces, and low level of blood flow, especially in the flaccid state. Therapeutic angiogenesis is an exciting field that continues to evolve. This review will focus on the development of growth factors for hypercholesterolemic ED, the use of various growth factors for ED therapy, their routes of delivery, and the results in animal studies.

Tumor angiogenesis and anti-angiogenic therapy

Anti-angiogenic drugs(AADs),which mainly target the vascular endothelial growth factor-A signaling pathway,have become a therapeutic option for cancer patients for two decades.During this period,tremendous clinical experience of anti-angiogenic therapy has been acquired,new AADs have been developed,and the clinical indications for AAD treatment of various cancers have been expanded using monotherapy and combination therapy.However,improvements in the therapeutic outcomes of clinically available AADs and the development of more effective next-generation AADs are still urgently required.This review aims to provide historical and perspective views on tumor angiogenesis to allow readers to gain mechanistic insights and learn new therapeutic development.We revisit the history of concept initiation and AAD discovery,and summarize the up-to-date clinical translation of anti-angiogenic cancer therapy in this field.

EXPRESSION OF BASIC FIBROBLAST GROWTH FACTOR,TRANSFORMING GROWTH FACTOR β_1 AND THEIRRECEPTORS IN OSTEOSARCOMA AND ITSRELATIONSHIP TO ANGIOGENESIS

Objective: To investigate the expression ofangiogenic factors, basic fibroblast growth factor (bFGF)and transforming growth factor (TGF)-β1 inosteosarcoma, its association with neovascularizationand prognosis. Methods: The expression of bFGF, TGFβ1 and their receptors, as well as intratumoralmicrovcssel count (MVD) were studied in 80osteosarcomas by immunohistochemical staining andmorphometry. The relationship between the angiogenicfactors expression and prognosis was evaluated by amultivariate analysis using Cox proportion hazardmodel. Results: Among 80 cases of osteosarcoma, 46cases were positive for bFGFlbFGFr (57.5%), and 31cases for TGF-β1/ TGF-β (RI)(38.8%) respectively. TheMVD and bFGF, TGF-β1, were important indicators topredict the prognosis of patients with osteosarconla bythe Cox proportion hazard model analysis. Conclusioll:The angiogenic factors bFGF and TGF-β1 are involvedin the angiogenesis of osteosarcoma, and theangiogenesis inf'luences the prognosis. Also they may beuseful in the evaluation of the prognosis of patients withosteosarcoma.

Development of the Relationship between Angiogenesis and Tumor Dormancy

Tumor dormancy, a complex and still poorly understood phenomenon, has been defined by the long-term persistence of occult can- cer cells during tumor progression. Recurrence and metastasis may occur just because of an activation of a small portion of the tumor cells. In our view, sustained angiogenesis is considered essential in triggering invasive tumor growth. Here we analyze the correlation between angiogenesis and tumor dormancy, the establishment of tumor dormancy models, the imaging strategies and the new biomarkers for dececting microscopic tumors before or during the angiogenic switch. It imperative to understand the role of an- giogenesis in tumor dormancy, as this will accelerate the development of anti-angiogenesis techniques to induce dormancy and/or eradicate dormant disease.

Role of angiogenesis and angiogenic factors in acute and chronic wound healing

Angiogenesis plays a crucial role in wound healing by forming new blood vessels from preexisting vessels by invading the wound clot and organizing into a microvascular network throughout the granulation tissue.This dynamic process is highly regulated by signals from both serum and the surrounding extracellular matrix environment.Vascular endothelial growth factor,angiopoietin,fibroblast growth factor and transforming growth factor-beta are among the potent angiogenic cytokines in wound angiogenesis.Specific endothelial cell ECM receptors are critical for morphogenetic changes in blood vessels during wound repair.In particular integrin(αvβ3)receptors for fibrin and fibronectin,appear to be required for wound angiogenesis:αvβ3 is focally expressed at the tips of angiogenic capillary sprouts invading the wound clot,and any functional inhibitors ofαvβ3 such as monoclonal antibodies,cyclic RGD peptide antagonists,and peptidomimetics rapidly inhibit granulation tissue formation.In spite of clear knowledge about influence of many angiogenic factors on wound healing,little progress has been made in defining the source of these factors,the regulatory events involved in wound angiogenesis and in the clinical use of angiogenic stimulants to promote repair.

Novel hepatocellular carcinoma molecules with prognostic and therapeutic potentials

Hepatocellular carcinoma(HCC), the predominant form of primary liver cancer, is the sixth most common cancer worldwide and the third leading cause of cancerrelated death. The difficulty to diagnose early cancer stages, the aggressive behaviors of HCC, and the poor effectiveness of therapeutic treatments, represent the reasons for the quite similar deaths per year and incidence number. Considering the fact that the diagnosis of HCC typically occurs in the advanced stages of the disease when the therapeutic options have only modest efficacy, the possibility to identify early diagnostic markers could be of significant benefit. So far, a large number of biomarkers have been associated to HCC progression and aggressiveness, but many of them turned out not to be of practical utility. This is the reason why active investigations are ongoing in this field. Given the huge amount of published works aimed at the identification of HCC biomarkers, in this review we mainly focused on the data published in the last year, with particular attention to the role of(1) molecular and biochemical cellular markers;(2) micro-interfering RNAs;(3) epigenetic variations; and(4) tumor stroma. It is worth mentioning that a significant number of the HCC markers described in the present review may be utilized also as targets for novel therapeutic approaches, indicating the tight relation between diagnosis and therapy. In conclusion, we believe that integrated researches among the different lines of investigation indicated above should represent the winning strategies to identify effective HCC markers and therapeutic targets.

Cyr61/CTGF/Nov family proteins in gastric carcinogenesis

Gastric cancer(GC)is the second leading cause of cancer-related death.The poor survival rate may reflect the relatively aggressive tumor biology of GC.Recently,the importance of the tumor microenvironment in carcinogenesis has emerged.In the tumor microenvironment,tumor cells and the surrounding stromal cells aberrantly secrete matricellular proteins capable of modulating carcinogenesis and regulating metastasis.The Cyr61/CTGF/Nov(CCN)proteins are a family of matricellular proteins with variable roles in many physiological and pathological processes.The evidence suggests that CCN family proteins contribute to GC carcinogenic processes.Here,we briefly review recent research on the effects of CCN family proteins in GC carcinogenesis and the development of new targeted agents in this field.

Supportive angiogenic and osteogenic differentiation of mesenchymal stromal cells and endothelial cells in monolayer and co-cultures

Sites of implantation with compromised biology may be unable to achieve the required level of angiogenic and osteogenic regeneration. The specific function and contribution of different cell types to the formation of prevascularized, osteogenic networks in co-culture remains unclear. To determine how bone marrow-derived mesenchymal stromal cells （BMSCs） and endothelial cells （ECs） contribute to cellular proangiogenic differentiation, we analysed the differentiation of BMSCs and ECs in standardized monolayer, Transwell and co-cultures. BMSCs were derived from the iliac bone marrow of five patients, characterized and differentiated in standardized monolayers, permeable Transwells and co-cultures with human umbilical vein ECs （HUVECs）. The expression levels of CD31, von Willebrand factor, osteonectin （ON） and Runx2 were assessed by quantitative reverse transcriptase polymerase chain reaction. The protein expression of alkaline phosphatase, ON and CD31 was demonstrated via histochemical and immunofluorescence analysis. The results showed that BMSCs and HUVECs were able to retain their lineage-specific osteogenic and angiogenic differentiation in direct and indirect co-cultures. In addition, BMSCs demonstrated a supportive expression of angiogenic function in co-culture, while HUVEC was able to improve the expression of osteogenic marker molecules in BMSCs.

Stretch-induced Expression of CYR61 Increases the Secretion of IL-8 in A549 Cells via the NF-κβ/Iκβ Pathway

Mechanical ventilation （MV） with large tidal volumes can increase lung alveolar permeability and initiate inflammatory responses, resulting in ventilator-induced lung injury （VILI）. The mechanisms of the injurious effects of MV and the genetic susceptibility remain unclear. VILI-related genes such as cysteine-rich angiogenic inducer 61 （Cyr61） have been demonstrated to play a detrimental role in the aggressive ventilation strategies. In the present study, we investigated the involvement of Cyr61 in the VILI and the underlying mechanism. A549 cells were exposed to cyclic stretch of varying durations and then the mRNA and protein levels of Cyr61 were measured by real-time PCR and Western blotting, respectively. Additionally, after exposure ofA549 cells to cyclic stretch for 5 min to 1 h, the expression levels of nuclear factor kappaB （NF-κβ） and IL-8 were detected by ELISA and Western blotting. Thereafter, Cyr61 expression was depressed in A549 cells with the siRNA pGenesill. 1-Cyr61-3 before the cyclic stretch, and IL-8 secretion and the activation of NF- κB pathways were probed by ELISA and Western blotting, respectively. Moreover, a NF- κB inhibitor （PDTC） and an activator （TNF） were used before mechanical stretch. Realtime PCR and ELISA were performed to detect the mRNA and protein of IL-8, respectively. The results showed that the mechanical cyclic stretch led to increased Cyr61 expression at mRNA and protein levels in A549 cells. Additionally, cyclic stretch also mobilized NF- κB from the cytoplasm to the nucleus and increased IL-8 secretion in A549 cells. The inhibition of Cyr61 blocked the NF-κB activation and IL-8 secretion in response to cyclic stretch. Inhibition of NF-κB attenuated the mRNA and protein expression of IL-8 in A549 cells transfected with Cyr61 siRNA. It was suggested that Cyr61/NF-κB signaling pathway mediates the upregulation of IL-8 in response to cyclic stretch in A594 cells. These findings support the hypothesis that Cyr61 plays a critical role in acute lung inflammation triggered by mechanical strain.

Assessment of serum angiogenic factors as a diagnostic aid for small bowel angiodysplasia in patients with obscure gastrointestinal bleeding and anaemia

To assess the use of serum levels of angiopoietin-1 (Ang1), Ang2 and tumor necrosis factor-α (TNFα) as predictive factors for small bowel angiodysplasia (SBA). METHODSSerum samples were collected from patients undergoing capsule endoscopy for any cause of obscure gastrointestinal bleeding (OGIB) or anaemia. Based on small bowel findings patients were divided into 3 groups: (1) SBA; (2) other bleeding causes; and (3) normal, according to diagnosis. Using ELISA technique we measured serum levels of Ang1, Ang2 and TNFα and compared mean and median levels between the groups based on small bowel diagnosis. Using receiver operator curve analysis we determined whether any of the factors were predictive of SBA. RESULTSSerum samples were collected from a total of 120 patients undergoing capsule endoscopy for OGIB or anaemia: 40 with SBA, 40 with other causes of small bowel bleeding, and 40 with normal small bowel findings. Mean and median serum levels were measured and compared between groups; patients with SBA had significantly higher median serum levels of Ang2 (3759 pg/mL) compared to both other groups, with no significant differences in levels of Ang1 or TNFα based on diagnosis. There were no differences in Ang2 levels between the other bleeding causes (2261 pg/mL) and normal (2620 pg/mL) groups. Using Receiver Operator Curve analysis, an Ang2 level of > 2600 pg/mL was found to be predictive of SBA, with an area under the curve of 0.7. Neither Ang1 or TNFα were useful as predictive markers. CONCLUSIONElevations in serum Ang2 are specific for SBA and not driven by other causes of bleeding and anaemia. Further work will determine whether Ang2 is useful as a diagnostic or prognostic marker for SBA.

Cyr61 Alleviates Cholangitis by Inhibiting Cytotoxic Effects of CD8^(+) T Cells on Biliary Epithelial Cells

Objective:Primary biliary cholangitis(PBC)is a chronic progressive cholestatic liver disease.In recent years,researchers have found that cysteine-rich angiogenic inducer 61(Cyr61,also known as CCN1)has a potential role in reducing portal inflammation in patients with PBC.This study aimed to explore the relationship between Cyr61 and PBC to provide new ideas and an experimental basis for the clinical treatment of PBC.Methods:After induction of the overexpression of Cyr61 in a mouse model of PBC using recombinant adenovirus,hematoxylin and eosin staining and pathological scores were used to indicate intrahepatic inflammation and bile duct damage.Real-time PCR was used to detect changes in inflammation-related cytokines in the liver.To further study the mechanism,we assessed whether Cyr61 protects bile duct epithelial cells from cytotoxic effects.Results:Serum and hepatic Cyr61 levels were increased in the murine model of PBC.Overexpression of Cyr61 alleviated hepatic inflammation and bile duct injury in vivo.Cyr61 inhibited the cytotoxic effects of CD8^(+)T cells by acting on biliary epithelial cells(BECs)in vitro.Conclusion:Our results provide novel insight into the pathogenesis of PBC and suggest that Cyr61 plays a dominant role in the cytotoxic effects on BECs in PBC.Consequently,therapeutic strategies targeting Cyr61 could be a potent therapy for PBC.

Study of the Influence of Angiostatin Intravitreal Injection on Vascular Leakage in Retina and Iris of the Experimental Diabetic Rats

Purpose: To examine the effect of an intravitreal injection of angiostatin on vascular leakage in retina and iris of the diabetes and study its possible mechanism. Methods: Experimental diabetes was induced in 24 rats by an intravenous injection of streptozotocin (STZ) during 48 adult rats. Three groups were randomization distributed of them. There were 8 of both normal and diabetic rats in each group. STZ-diabetic rats and age-matched normal rats received an intravitreal injection of 5 μl of sterile PBS (Phosphate Buffered Saline) into the right eye, and the left eye was non-injected in the group A; Angiostatin was injected into the vitreous of the right eye (7.5 μg / 5 μl / eye), and the left eye received the same volume of sterile PBS as the control in the group B and C. The vascular permeability of retina and iris was measured using the Evans blue method at 2 days following the injection in the group A and B. Expression of VEGF in retina was evaluated using western blot analysis 24 hours following the injection in the group C. Results: Diabetic rats showed significant increases of vascular permeability in the retina ( P < 0.01) and iris ( P < 0.05). Angiostatin-injected eyes showed significant decreases in vascular permeability in the retina ( P < 0.01) and iris ( P < 0.05) comparing with the PBS-injected eyes in STZ-diabetic rats. In contrast, intravitreal injection of the same dose of angiostatin into the age-matched normal rats did not result in any significant reduction in vascular permeability in the retina and iris, when compared with the contralateral eye with PBS injection ( P > 0.05). Angiostatin injection significantly reduced VEGF level in the retinas of STZ-diabetic rats but did not affect retinal VEGF level in normal rats. Conclusions: Angiostatin significantly reduce pathological vascular permeability in the retina and iris of STZ-diabetic rats but not in normal rats. Angiostatin down-regulates VEGF expression and thus, blocks the major cause of vascular leakage in the diabetic retina. Therefore, angiostatin may have a therapeutic potential in the treatment of diabetic macular edema, cystoid macular edema, uvietis and other diseases with vascular leakage.

Tadalafil treatment had a modest effect on endothelial cell damage and repair ability markers in men with erectile dysfunction and vascular risk

The number of the circulating angiogenic cells （CACs） and colony forming units （CFUs） derived from cultured circulating mononuclear cells （MNCs） represents a laboratory surrogate for endothelial cell repair ability. The serum of men with erectile dysfunction （ED） and vascular risk factors （VRFs） showed an increased level of endothelial cell damage/dysfunction markers and reduced the numbers of CACs and CFUs derived from the cells of healthy men. We analyzed whether treating men with ED and VRFs with the selective phosphodiesterase type 5 inhibitor tadalafil improved the endothelial cell repair ability and reduced the levels of the serum markers of endothelial cell damage/dysfunction. MNCs from healthy men were cultured with 20% serum from 36 ED patients to obtain CACs and CFUs. The ED patients were evaluated before and after 4weeks of treatment with tadalafil （20 mg every other day） or with a placebo. The tadalafil treatment improved erectile function （P = 0.0028）, but had no effect on the inhibitory effects of serum from ED patients on the CACs and CFUs derived from healthy men. The levels of endothelin-1 （P = 0.011） and tissue type plasminogen activator （P = 0.005） were reduced after treatment compared to baseline and those of the placebo group, whereas no changes were observed in the E-selectin levels. The tadalafil treatment in the ED patients with VRFs resulted in only a modest effect on the laboratory measures of the endothelial cell damage/dysfunction and repair ability. The proposed beneficial effect of phosphodiesterase type 5 inhibition on vascular homeostasis requires further analysis.

A comparative study on the angiogenic activity of condyloma acuminatum and basal cell carcinoma

Recently, the study on the extraction, component analysis and function of angiogenic factor (AF) has become an important subject in anti-tumor research and made a great progress. Therefore, the imitation of the tumor's angiogenic activity (AGA) possibly helps to find a new method to treat ischemic diseases by blood vessel proliferation. Most of the parenchymatous malignant tumors have AGA. We studied the early stage condyloma acuminatum (CA) . After transplanting CA onto the chorioallantoic membrane (CAM) of chick embryos, we observed the AGA of CA and carefully compared it with that of basal cell carcinoma which is generally considered to have strong AGA. Meanwhile, we explored the way by which the AF of CA comes into being. The results demonstrated that CA, a benign neoplastic lesion, at its early stage, also has AGA. It is postulated that the responsible material is a certain form of AF. Therefore, the study on AGA of benign lesions (such as CA) and its physical basis will have potential clinical significance.

Role of Anti Angiogenic Therapy in Prevention of Recurrence in Hormonal Positive Breast Cancer: A Secondary Prevention Strategy and Method of Therapy

Existing literature supports the role of signaling protein vascular endothelial growth factor (VEGF) in tumor growth and metastasis and furthers its involvement in recurrence. In both experimental and clinical studies, VEGF has been shown to be a significant factor involved for aberrant blood vessel growth, and in fact is the target of several classes of antineoplastic drugs [1] [2] [3] [4]. That said, the current standard of care for estrogen receptor positive breast cancer (although improved over the last decade), has not provided a “meaningful preventive shift” since the discovery of angiogenesis and its role in induction of recurrence. In this article, we discuss an anti angiogenic therapy implementing natural compounds to inhibit the production of VEGF. We applied our preclinical data to justify the predicted effect on VEGF. We used liquid biopsy to monitor patients response to therapy as a surrogate for recurrence. We hypothesize that by inhibition of angiogenesis through this protocol, we are able to positively impact tumor recurrence. It is our experience that patients in our sample even with high recurrence scores (based on Oncotype Dx testing) had a major reduction in recurrence when estrogen blockers were combined with this protocol. We also propose longitudinal studies to compare outcomes with combinational therapies with estrogen blockers in highly expected to recur disease.

Complement C3a signaling mediates production of angiogenic factors in mesenchymal stem cells

A major portion of the beneficial effect of mesenchymal stem cells (MSC) is due to the production of trophic and angiogenic factors by these cells, and one of the efforts to improve the therapeutic efficacy of these cells lies in enhancing this capacity. Since there is complement activation in all areas of tissue injury, and both C3a and C5a activate MSC, it was asked whether stimulation with C3a or C5a would upregulate the production of trophic factors by MSC. C3a caused significant up-regulation of various angiogenic factors, including VEGF, CXCL8/IL-8 and IL-6. In contrast there was no detectable production of the pro-inflammatory cytokines TNF-α and IL-1β in spite of nuclear translocation of NFκB. Although C5a also caused moderate up-regulation of angiogenic factors, the effect was borderline significant. Furthermore the production of angiogenic factors induced by C3a was of physiological relevance: Supernatants of MSCs cultured under serum-free conditions induced minimal tube formation of HUVECs as an in vitro measure of angiogenesis;tube formation was considerably enhanced, when supernatants from C3a-stimulated MSC were used, while C3a itself had no direct angiogenic effect on HUVECs. The signaling cascade responsible for the production of angiogenic factors by C3a or C5a could be defined as activation of the rho cascade which was necessary for nuclear translocation of NFκB p65 and of phospho-ERK1/2. Although rho was only transiently activated, inhibition of the rho or “downstream of it” of the NFκB pathway, prevented C3a-and C5a-induced up-regulation of angiogenic factors.

Placenta related pathogenic factors for preeclampsia

Preeclampsia (PE) is a life-threatening complication of pregnancy. The precise origin of PE remains obscure. Placenta has been considered to play a central role in its pathology. Here we present a brief overlook of placenta related pathogenic factors that might be involved in the pathology changes of PE. A series of factors that correlated with placenta pathology have been regarded attributed to the mechanism of the disease. Some of the factors may be confirmed to be useful biomarkers in the early prediction and monitoring of the disease in a future.