Recent advance in molecular angiogenesis in glioblastoma: the challenge and hope for anti-angiogenic therapy

Glioblastoma (GBM) is the most highly malignant brain tumor in the human central nerve system. In this paper, we review new and significant molecular findings on angiogenesis and possible resistance mechanisms. Expression of a number of genes and regulators has been shown to be upregulated in GBM microvessel cells, such as interleukin-8, signal transducer and activator of transcription 3, Tax-interacting protein-1, hypoxia induced factor-1 and anterior gradient protein 2. The regulator factors that may strongly promote angiogenesis by promoting endothelial cell metastasis, changing the microenvironment, enhancing the ability of resistance to anti-angiogenic therapy, and that inhibit angiogenesis are reviewed. Based on the current knowledge, several potential targets and strategies are proposed for better therapeutic outcomes, such as its mRNA interference of DII4-Notch signaling pathway and depletion of b1 integrin expression. We also discuss possible mechanisms underlying the resistance to anti-angiogenesis and future directions and challenges in developing new targeted therapy for GBM.

Discovery of novel VEGFR-2 inhibitors. Part 5: Exploration of diverse hinge-binding fragments via core-refining approach

Pathological angiogenesis plays a critical role in numerous diseases including malignancy. VEGFR-2 is the central regulators in angiogenesis and has become a promising target for anticancer drug design. We have identified a novel biphenyl-aryl urea incorporated with salicyladoxime (BPS-7) as potent VEGFR-2 inhibitor. As a continuation to our previous research, various aromatic-heterocyclic were introduced as hinge-binding fragment via a core-refining approach. Interestingly, many compounds exhibited comparable VEGFR-2 inhibition to Sorafenib. In particular, 12e and 12o displayed excellent VEGFR-2 inhibitory activity with IC₅₀ values of 0.50 nM and 0.79 nM, respectively. Several title compounds showed considerable antiproliferative activity against A549 and SMMC-7721 cells. In addition, molecular docking was performed to rationalize the efficiency of the better compounds. These results will be instructive for further inhibitor design and optimization.

Immunoglobulin Fc-fused, neuropilin-1-specific peptide shows efficient tumor tissue penetration and inhibits tumor growth via anti-angiogenesis

Neuropilin-1 (NRP1) receptor, involved in vascular endothelial growth factor (VEGF)-mediated vascular permeability and tumor angiogenesis, is targeted by peptides that bind to its VEGF-binding site. However, these peptides also cross-react with the structurally related receptor, NRP2. Here, we describe an immunoglobulin Fc-fused peptide, Fc-TPP11, which specifically binds to the VEGF-binding site of NRP1 with approximately 2nM affinity, but negligibly to that of NRP2. Fc-TPP11 triggered NRP1-dependent signaling, enhanced vascular permeability via vascular endothelial (VE)-cadherin downregulation, and increased paracellular permeability via E-cadherin downregulation in tumor tissues. Fc-TPP11 also significantly enhanced the tumor penetration of co-injected anti-cancer drug, doxorubicin, leading to the improved in vivo anti-tumor efficacy. Fc-TPP11 was easily adapted to the full-length anti-epidermal growth factor receptor (EGFR) monoclonal antibody (mAb) cetuximab (Erbitux), cetuximab-TPP11, exhibiting more than 2-fold improved tumor penetration than the parent cetuximab. Fc-TPP11 exhibited a similar whole-body half-life to that of intact Fc in tumor bearing mice. In addition to the tumor-penetrating activity, Fc-TPP11 suppressed VEGF-dependent angiogenesis by blocking VEGF binding to NRP1, thereby inhibiting tumor growth without promoting metastasis in the mouse model. Our results show that NRP1-specific, high-affinity binding of Fc-TPP11, is useful to validate NRP1 signaling, independent of NRP2. Thus, Fc-TPP11 can be used as a tumor penetration-promoting agent with anti-angiogenic activity or directly adapted to mAb-TPP11 format for more potent anti-cancer antibody therapy.

Anti-tumor activity of the proteasome inhibitor BSc2118 against human multiple myeloma

Introduction of bortezomib, the first generation of proteasome inhibitor, has significantly improved the median overall survival of patients with multiple myeloma (MM). However, the dose-limiting adverse events and acquired drug resistance limit its long-term usage. Here, we report in vitro and in vivo anti-MM activity of the irreversible proteasome inhibitor BSc2118. BSc2118 inhibited the chymotrypsin-like (CT-L) proteasome activity, accompanied by accumulation of ubiquitinated proteins. BSc2118 suppressed tumor cell growth through induction of G2/M phase arrest and induced apoptosis via activation of the apoptotic signaling cascade, in association with up-regulation of p53 and p21. Importantly, BSc2118 was active in vitro against MM cells' acquired bortezomib resistance. Of note, BSc2118 also displayed a novel anti-angiogenesis activity both in vitro and in vivo. Lastly, BSc2118 exhibited a broader safety dose range and higher anti-tumor efficacy in vivo in a human MM xenograft mouse model, compared to bortezomib. Together, these findings indicate the in vitro and in vivo anti-MM activities of BSc2118 through induction of cell cycle arrest and apoptosis, as well as inhibition of tumor angiogenesis. They also suggest that BSc2118 might, at least in vitro, partially overcome acquired bortezomib resistance, likely associated with inhibition of autophagy.

In vitro inhibition of angiogenesis by heat and low pH stable hydroalcoholic extract of Peganum harmala seeds via inhibition of cell proliferation and suppression of VEGF secretion

CONTEXT

Progression of cancer cells is completely dependent on its angiogenesis. Inhibition of tumor angiogenesis has shed new light on cancer treatment. As a result, anti-angiogenesis therapy represents one of the most significant advances in clinical oncology. Peganum harmala L. (Zygophyllaceae) is a native plant from the eastern Iranian region, which is used as a traditional folk medicine. Although some biological properties of this plant are determined, its effect on angiogenesis is still unclear.

OBJECTIVE

We investigated the anti-angiogenic effects of heat and low pH stable hydroalcoholic extract of P. harmala seeds on endothelial cells (ECs) proliferation and VEGF secretion.

MATERIALS AND METHODS

Dried Peganum seeds were purchased from Kermanshah Traditional Bazar in 2011. Hydroalcoholic extract of dried seeds (0, 10, 20, 40, 60, 80, 100, 120, and 150 μg/ml) was used for in vitro evaluation of its cytotoxicity, anti-proliferative, and anti-angiogenic effects on ECs. In vitro effect of the extract on VEGF secretion was assayed using ELISA.

RESULTS

Treatment with hydroalcoholic extract at seven different concentrations resulted in significant decrease of ECs proliferation and angiogenesis with an ID50 of ∼ 85 μg/ml. VEGF secretion was (inhibited) decreased by the extracts at concentrations higher than 10 μg/ml.

DISCUSSION AND CONCLUSION

Herbal plant extracts still attract attention owing to their fewer side effects comparing to synthetic drug agents. Current study indicated that hydroalcoholic extract of P. harmala seeds contains a potent anti-angiogenic component, which exerts its inhibitory effect mainly through down-regulation of essential mediators such as VEGF.

Structural elucidation of a polysaccharide from Chrysanthemum morifolium flowers with anti-angiogenic activity

The flowers of Chrysanthemum morifolium were extracted with 5% sodium hydroxide, yielding a neutral polysaccharide (JHB0S2) with a molecular weight of 16 kDa by anion-exchange chromatography on a DEAE-cellulose column and gel permeation chromatography on a Sephacryl S-200 HR column. JHB0S2 was found to contain glucose, xylose, arabinose and galactose in molar ratio of 2.9:2.3:1.0:1.2. Through the linkage analysis, partial acid hydrolysis and NMR spectra and so forth, indicated that its backbone consisted of 1,4-linked β-Glcp, nearly 50% of which was substituted at O-6 by 1,2-linked α-Xylp terminated with Galp or Xylp. Furthermore, some of 1,2-linked α-Xylp was substituted at O-4 by α-Araf-(1→5)-α-Araf-(1→6)-β-Galp. The biological test showed that JHB0S2 could inhibit the tube formation of HMEC-1 cells.

Flavonoids as a scaffold for development of novel anti-angiogenic agents: An experimental and computational enquiry

Relationship between structural diversity and biological activities of flavonoids has remained an important discourse in the mainstream of flavonoid research. In the current study anti-angiogenic, cytotoxic, antioxidant and cyclooxygenase (COX) inhibitory activities of diverse class of flavonoids including hydroxyl and methoxy substituted flavones, flavonones and flavonols have been evaluated in the light of developing flavonoids as a potential scaffold for designing novel anti-antiangiogenic agents. We demonstrate anti-angiogenic potential of flavonoids using in vivo chorioallantoic membrane model (CAM) and further elaborate the possible structural reasoning behind observed anti-angiogenic effect using in silico methods. Additionally, we report antioxidant potential and kinetics of free radical scavenging activity using DPPH and SOR scavenging assays. Current study indicates that selected flavonoids possess considerable COX inhibition potential. Furthermore, we describe cytotoxicity of flavonoids against selected cancer cell lines using MTT cell viability assay. Structural analysis of in silico docking poses and predicted binding free energy values are not only in accordance with the experimental anti-angiogenic CAM values from this study but also are in agreement with the previously reported literature on crystallographic data concerning EGFR and VEGFR inhibition.

MiRNA-21 silencing mediated by tumor-targeted nanoparticles combined with sunitinib: A new multimodal gene therapy approach for glioblastoma

Malignant brain tumors, including glioblastoma (GBM), are among the most lethal human cancers, due to their tremendous invasive capacity and limited therapeutic options. Despite remarkable advances in cancer theranostics, which resulted in significant improvement of clinical outcomes, GBM relapse is very frequent and patient survival remains under one year. The elucidation of the role of abnormally-expressed miRNAs in different steps of GBM pathogenesis and in tumor resistance to therapy paved the way for the development of new miRNA-based therapeutic approaches targeting this disease, aiming at increasing specific tumor cell killing and, ultimately, cancer eradication. Here, we demonstrate that intravenously-administered chlorotoxin (CTX)-coupled (targeted) stable nucleic acid lipid particle (SNALP)-formulated anti-miR-21 oligonucleotides accumulate preferentially within brain tumors and promote efficient miR-21 silencing, which results in increased mRNA and protein levels of its target RhoB, while showing no signs of systemic immunogenicity. Decreased tumor cell proliferation and tumor size, as well as enhanced apoptosis activation and, to a lesser extent, improvement of animal survival, were also observed in GBM-bearing mice upon systemic delivery of targeted nanoparticle-formulated anti-miR-21 oligonucleotides and exposure to the tyrosine kinase inhibitor sunitinib. Overall, our results provide evidence that CTX-coupled SNALPs are a reliable and efficient system for systemic delivery of anti-miRNA oligonucleotides. Moreover, although further studies are still necessary to demonstrate a therapeutic benefit in a clinical context, our findings suggest that miRNA modulation by the targeted nanoparticles combined with anti-angiogenic chemotherapy may hold promise as an attractive approach towards GBM treatment.

In vitro anti-angiogenic effects of Hemidesmus indicus in hypoxic and normoxic conditions

ETHNOPHARMACOLOGICAL RELEVANCE

The decoction of the roots of Hemidesmus indicus is widely used in the Indian traditional medicine for many purposes and poly-herbal preparations containing Hemidesmus are often used by traditional medical practitioners for the treatment of cancer. In the context of anticancer pharmacology, anti-angiogenic therapy has become an effective strategy for inhibiting new vessel formation and contrast tumor growth. These considerations are supported by the evidence that most tumors originate in hypoxic conditions and limitation of oxygen diffusion stimulates the formation of tumor abnormal microvasculature. Aim of this study was to evaluate the in vitro anti-angiogenic potential of Hemidesmus indicus (0.31-0.93 mg/mL) on human umbilical vein endothelial cells and delineate the main molecular mechanisms involved in its anti-angiogenic activity both in normoxia and hypoxia.

MATERIALS AND METHODS

The decoction of Hemidesmus indicus was subjected to an extensive HPLC phytochemical characterization. Its in vitro anti-angiogenic potential was investigated in normoxia and hypoxia. Cell proliferation, apoptosis induction, and inhibition of endothelial cell migration and invasion were analyzed by flow cytometry. The endothelial tube formation assay was evaluated in matrix gel. The capillary tube branch points formed were counted using a Motic AE21 microscope and a VisiCam videocamera. The regulation of key factors of the neovascularization process such as VEGF, HIF-1α and VEGFR-2 was explored at mRNA and protein level by real time PCR and flow cytometry, respectively.

RESULTS

Treatment with Hemidesmus resulted in a significant inhibition of cell proliferation and tube formation in both normoxia and hypoxia. Hemidesmus differently regulated multiple molecular targets related to angiogenesis according to oxygen availability. In normoxia, the inhibition of VEGF was the main responsible for its anti-angiogenic effect; the angiogenesis inhibition induced in hypoxia was regulated by a more complex mechanism involving firstly HIF-1α inhibition, and then VEGF and VEGFR-2 down-regulation. Additionally, the inhibition of endothelial cell migration and invasion by Hemidesmus was more pronounced in normoxia than in hypoxia, possibly due to the physiological enhanced induction of invasion characteristic of hypoxia.

CONCLUSIONS

Our results indicate that Hemidesmus might represent a promising therapeutic strategy for diseases in which the inhibition of angiogenesis could be beneficial, such as cancer. The antiangiogenic activity of Hemidesmus is based on multiple interactions with critical steps in the angiogenic cascade. VEGF expression stimulated by HIF-1α as well as endothelial cell migration and differentiation represent important targets of Hemidesmus action and might contribute to its cancer therapeutic efficacy that is presently emerging and offer a scientific basis for its use in traditional medicine.

Advances in anti-angiogenic agents for ovarian cancer treatment: The role of trebananib (AMG 386)

Ovarian cancer is a multifaceted and genomically complex disease and has emerged as leading cause of death among gynecological malignancies. Gold-standard treatment consisted of cytoreductive surgery and paclitaxel-carboplatin chemotherapy. Recently, promising results of randomized trials have definitively confirmed the importance of angiogenesis in oncogenesis and ovarian cancer behavior, by showing a significant prolongation of progression-free survival with the addiction of an angiogenesis inhibitor to standard treatment in the first and second line setting. Research over the years has sequentially provided a rapidly broadening signaling landscape and many drugs targeting different signaling pathways of angiogenesis have been developed and investigated. Recently accumulating scientific evidence has started to shed light on the efficacy of AMG 386, a new peptibody reported to neutralize the interaction between angiopoietins (Ang1/2) and their Tie2 receptors, thus representing a promising alternative, both in terms of efficacy and toxicity profile and is considerably under investigation. The aim of this review is to summarize the recent researches and clinical progresses of AMG 386 as a novel target agent in ovarian cancer.

iTRAQ-based proteomic identification of proteins involved in anti-angiogenic effects of Panduratin A on HUVECs

Panduratin A (PA), a cyclohexanyl chalcone from Boesenbergia rotunda (L.) Mansf. was shown to possess anti-angiogenic effects in our previous study. In the present study, the molecular targets and anti-angiogenic mechanisms of PA on human umbilical vein endothelial cells (HUVECs) were identified using an iTRAQ-based quantitative proteomics approach. A total of 263 proteins were found to be differentially regulated in response to treatment with PA. Ingenuity Pathway Analysis revealed that cellular growth and proliferation, protein synthesis, RNA post-transcriptional modification, cellular assembly and organization and cell-to-cell signaling and interaction were the most significantly deregulated molecular and cellular functions in PA-treated HUVECs. PA inhibited the expressions of ARPC2 and CTNND1 that are associated with the formation of actin cytoskeleton, focal adhesion and cellular protrusions. In addition, PA down-regulated CD63, GRB-2, ICAM-2 and STAB-1 that are implicated in adhesion, migration and tube formation of endothelial cells. The differential expressions of three targets, namely, ARPC2, CDK4, and GRB-2 were validated by western blot analyses. Furthermore, PA inhibited G1-S progression, and resulted in G0/G1 arrest in HUVECs. The blockage in cell cycle progression was accompanied with the suppression of mTOR signaling. Treatment of HUVECs with PA resulted in decreased phosphorylation of ribosomal S6 and 4EBP1 proteins, the two downstream effectors of mTOR signaling. We further showed that PA is able to inhibit mTOR signaling induced by VEGF, a potent inducer of angiogenesis. Taken together, by integrating quantitative proteomic approach, we identified protein targets in which PA mediates its anti-angiogenic effects. The present study thus provides mechanistic evidence to the previously reported multifaceted anti-angiogenic effects of PA. Our study further identified mTOR signaling as an important target of PA, and therefore highlights the potential of PA for therapeutic intervention against angiogenesis-related pathogenesis, particularly, metastatic malignancy.

Role of anti-angiogenesis therapy in the management of hepatocellular carcinoma: The jury is still out

As the leading cause of disease-related deaths, cancer is a major public health threat worldwide. Surgical resection is still the first-line therapy for patients with early-stage cancers. However, postoperative relapse and metastasis remain the cause of 90% of deaths of patients with solid organ malignancies, including hepatocellular carcinoma (HCC). With the rapid development of molecular biology techniques in recent years, molecularly targeted therapies using monoclonal antibodies, small molecules, and vaccines have become a milestone in cancer therapeutic by significantly improving the survival of cancer patients, and have opened a window of hope for patients with advanced cancer. Hypervascularization is a major characteristic of HCC. It has been reported that anti-angiogenic treatments, which inhibit blood vessel formation, are highly effective for treating HCC. However, the efficacy and safety of anti-angiogenesis therapies remain controversial. Sorafenib is an oral multikinase inhibitor with anti-proliferative and anti-angiogenic effects and is the first molecular target drug approved for the treatment of advanced HCC. While sorafenib has shown promising therapeutic effects, substantial evidence of primary and acquired resistance to sorafenib has been reported. Numerous clinical trials have been conducted to evaluate a large number of molecularly targeted drugs for treating HCC, but most drugs exhibited less efficacy and/or higher toxicity compared to sorafenib. Therefore, understanding the mechanism(s) underlying sorafenib resistance of cancer cells is highlighted for efficiently treating HCC. This concise review aims to provide an overview of anti-angiogenesis therapy in the management of HCC and to discuss the common mechanisms of resistance to anti-angiogenesis therapies.

Tryptase, a novel angiogenic factor stored in mast cell granules

Human mast cells (MCs) are a rich reservoir of neutral proteases, packed in large amounts in their granules and comprising a high fraction of all cellular proteins. Among these proteases, tryptase is involved in angiogenesis after its release from activated MC granules, as it has been demonstrated in different in vitro and in vivo assays. Moreover, tryptase-positive MCs increase in number and vascularization increases in a linear fashion in different solid and hematological tumors. This complex interplay between MCs and tumor angiogenesis have led to consider the therapeutic use of angiogenesis inhibitors, which specifically target the angiogenic activity of tryptase, such as gabexate mesilate and nafamostat mesilate, two inhibitors of trypsin-like serine proteases.

Cancer, sunlight and vitamin D

The sunshine vitamin has been associated with reduced risk for many chronic illnesses including cancer and cancer mortality. Epidemiologic and ecological studies have suggested that living at higher latitudes and having lower blood levels of 25-hydroxyvitamin D are associated with increased risk for up to 15 cancers including breast, colon, lung, lymphoma, pancreatic, ovarian and prostate cancer. Most randomized controlled trials using appropriate doses of vitamin D have suggested that improvement in vitamin D status reduces risk for several cancers. Although the exact mechanism by which enhanced vitamin D status reduces risk for cancer is not completely understood, there is evidence that by raising blood levels of 25-hydroxyvitamin D this metabolite can enter a wide variety of cells in the body and then be converted to 1,25-dihydroxyvitamin D3. The vitamin D metabolite, 1,25-dihydroxyvitamin D3, has been demonstrated to markedly reduce cellular proliferation especially of malignant cells that have a vitamin D receptor. It also induces terminal differentiation. 1,25-dihydroxyvitamin D3 is also anti-angiogenic and pro-apoptotic which also plays a role in reducing the growth and spread of malignant cells. Thus improvement in vitamin D status with sensible sun exposure, vitamin D supplementation and ingesting foods containing vitamin D is a reasonable strategy to reduce risk of malignancy.

and its cytotoxic, anti-angiogenesis and antiviral properties

The aqueous extraction of the sesquiterpene lactone xanthatin from Xanthium spinosum L. favours the conversion of xanthinin (1) to xanthatin (2) via the loss of acetic acid. The cytotoxic (Hep-G2 and L1210 human cell lines) and antiviral activities of isolated xanthatin are established. This natural compound shows significant cytotoxicity against the Hep-G2 cell line and our experimental results reveal its strong anti-angiogenesis capacity in vitro. The structure of xanthatin is determined by spectroscopic methods and for the first time confirmed by X-ray diffraction.

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A method to maximize extraction of xanthatin is proposed.

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X-ray crystal of xanthatin is contributed by the first time and confirms the structure.

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Antitumor, antiviral and antiangiogenesis activities of xanthatin are performed.

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Xanthatin exhibited potent antiangiogenic activity.

Enhanced anti-angiogenic effect of E7820 in combination with erlotinib in epidermal growth factor receptor-tyrosine kinase inhibitor-resistant non-small-cell lung cancer xenograft models

Most non-small-cell lung cancers (NSCLCs) harboring activating mutations in the epidermal growth factor receptor (EGFR) are initially responsive to EGFR tyrosine kinase inhibitors (EGFR-TKIs); however, they invariably develop resistance to these drugs. E7820 is an angiogenesis inhibitor that decreases integrin-α2 expression and is currently undergoing clinical trials. We investigated whether E7820 in combination with erlotinib, an EGFR-TKI, could overcome EGFR-TKI-resistance in the NSCLC cell lines A549 (KRAS; G12S), H1975 (EGFR; L858R/T790M), and H1650 (PTEN; loss, EGFR; exon 19 deletion), which are resistant to erlotinib. Immunohistochemical analysis was carried out in xenografted tumors to investigate anti-angiogenesis activity and endothelial cell apoptosis levels by endothelial cell marker CD31 and TUNEL staining, respectively. Treatment with E7820 (50 mg/kg) with erlotinib (60 mg/kg) showed a synergistic antitumor effect in three xenograft models. Immunohistochemical analysis indicated that combined treatment with E7820 and erlotinib significantly decreased microvessel density and increased apoptosis of tumor-associated endothelial cells compared with use of only one of the agents. This combination increased apoptosis in HUVECs through activation of both intrinsic and extrinsic apoptosis pathways in vitro. The combination of E7820 with erlotinib is an alternative strategy to overcome erlotinib resistance in NSCLC by enhancement of the anti-angiogenic activity of E7820.

Gene therapy in pancreatic cancer

Pancreatic cancer (PC) is a highly lethal disease and notoriously difficult to treat. Only a small proportion of PC patients are eligible for surgical resection, whilst conventional chemoradiotherapy only has a modest effect with substantial toxicity. Gene therapy has become a new widely investigated therapeutic approach for PC. This article reviews the basic rationale, gene delivery methods, therapeutic targets and developments of laboratory research and clinical trials in gene therapy of PC by searching the literature published in English using the PubMed database and analyzing clinical trials registered on the Gene Therapy Clinical Trials Worldwide website (http://www. wiley.co.uk/genmed/ clinical). Viral vectors are main gene delivery tools in gene therapy of cancer, and especially, oncolytic virus shows brighter prospect due to its tumor-targeting property. Efficient therapeutic targets for gene therapy include tumor suppressor gene p53, mutant oncogene K-ras, anti-angiogenesis gene VEGFR, suicide gene HSK-TK, cytosine deaminase and cytochrome p450, multiple cytokine genes and so on. Combining different targets or combination strategies with traditional chemoradiotherapy may be a more effective approach to improve the efficacy of cancer gene therapy. Cancer gene therapy is not yet applied in clinical practice, but basic and clinical studies have demonstrated its safety and clinical benefits. Gene therapy will be a new and promising field for the treatment of PC.

Metronomic chemotherapy

Toxic effects and chemoresistance are major hurdles in chemotherapy and to avoid these problems caused by traditional chemotherapeutic regimens, a new modality of drug administration called “metronomic chemotherapy” has emerged. Such regimen involves the frequent administration of conventional chemotherapeutic agents at very low doses to target activated endothelial cells in tumors, the advantages of which include minimal adverse effects and a rare chance of developing acquired drug resistance. Previously it was thought that they act by targeting angiogenesis, but recently additional mechanisms have been discovered which has established metronomic chemotherapy as a type of multi-targeted therapy. The knowledge gained from the preclinical studies of metronomic chemotherapy, along with clinical experience, will help to design better therapeutic protocols against cancer. Detailed pharmacogenomic and pharmacoproteomic studies on tumor endothelial cells and large multi-centered clinical trials, integrating bio-marker analyzes, are needed to investigate and validate the best treatment combinations for each tumor type and patient population.

AAV-mediated persistent bevacizumab therapy suppresses tumor growth of ovarian cancer

RATIONALE

Anti-angiogenesis therapies such as bevacizumab, the monoclonal antibody to vascular endothelial growth factor (VEGF), have been used against ovarian cancer, but transient and low peritoneal drug levels are likely a factor in treatment failure. We hypothesized that a single administration of adeno-associated virus (AAV)-mediated intraperitoneal expression of bevacizumab would direct persistent expression and suppress growth and metastasis of ovarian cancer.

METHODS

AAVrh.10BevMab, a rhesus serotype 10 adeno-associated viral vector coding for bevacizumab, was evaluated for the capacity of a single intraperitoneal administration to persistently suppress peritoneal tumor growth in an intraperitoneal model of ovarian carcinomatosis with human ovarian cancer cells in nude immunodeficient mice.

RESULTS

The data demonstrates that AAVrh10.BevMab mediates persistent and high levels of bevacizumab in the peritoneal cavity following a single intraperitoneal administration in mice. In AAVrh10.BevMab treated A2780 human ovarian cancer-bearing mice, tumor growth was significantly suppressed (p<0.05) and the area of blood vessels in the tumor was decreased (p<0.04). Survival of mice with A2780 xenografts or SK-OV3 xenografts was greatly prolonged in the presence of AAVrh10.BevMab (p<0.001). Administration of AAVrh10.BevMab 4days after A2780-luciferase cell implantation reduced tumor growth (p<0.01) and increased mouse survival (p<0.0001). Combination of AAVrh10.BevMab with cytotoxic reagents paclitaxel or topotecan proved to be more effective in increasing survival than treatment with cytotoxic reagent alone.

CONCLUSION

A single administration of AAVrh10.BevMab provides sustained and high local expression of bevacizumab in the peritoneal cavity, and significantly suppresses peritoneal carcinomatosis and increases survival in an ovarian cancer murine model.

Ageing-related responses to antiangiogenic effects of sunitinib in atherosclerosis-prone mice

Antiangiogenic therapies in cancer exert their effects in the context of age-related comorbidities, which affect the entirety of the vascular system. Among those conditions, the impact of atherosclerosis is especially prevalent, but poorly understood, and not reflected in mouse models routinely used for testing antiangiogenic therapeutics. Our earlier work suggested that these obstacles can be overcome with the use of atherosclerosis-prone ApoE-/- mice harbouring syngeneic transplantable Lewis Lung Carcinoma (LLC). Here we report that, sunitinib, the clinically approved, antiangiogenic inhibitor impedes global tumor growth to a greater extent in aged then in young mice. This activity was coupled with changes in the tumor microenvironment, which in aged mice was characterized by pronounced hypoxia, reduction in microvascular density (MVD) and lower pericyte coverage, relative to young controls. We also detected soluble VEGR2 in plasma of sunitinib treated mice. Interestingly, sunitinib modulated tumor infiltration with bone marrow-derived cells (CD45+), recruitment of M2-like macrophages (CD163+) and activation of inflammatory pathways (phospho-STAT3) in a manner that was age-dependent. We suggest that age and atherosclerosis may alter the effects of sunitinib on the tumor microenvironment, and that these considerations may also apply more broadly to other forms of antiangiogenic treatment in cancer.

Ocular surface rehabilitation: Application of human amniotic membrane in high-risk penetrating keratoplasties

BACKGROUND

Human amniotic membrane is a versatile tool for management of ocular surface disorders. This study evaluates the effect of cryopreserved human amniotic membrane (hAM) on one-year survival of penetrating keratoplasties (PKP) in high-risk recipients.

METHOD

This is a retrospective noncomparative cohort study of 58 consecutive eyes undergoing PKP with concurrent placement of a self-retained cryopreserved hAM (PROKERA®) at a tertiary care center from January 2009 to July 2010.

RESULTS

Mean patient age was 66.7 ± 17.2 years and 30 (54%) were males. 51 eyes were pseudophakic and one aphakic. 27 eyes were glaucomatous; 24 had glaucoma drainage device and 2 had previous endocyclophotocoagulation. 12 patients had PKP for the first time and 46 had repeat PKP (average number of prior PKP = 1.63 ± 1.1, range: 1-5). Risk factors for graft failure included repeat PKP (79.3%), corneal neovascularization (51.7%), preexisting glaucoma (46.6%), and presence of anterior synechiae (37.9%). Both First Transplant and Repeat Transplant groups had similar survival rates until 6 months after transplant (75% vs 74%, odds ratio = 1.06, p = 1.00). At 12 months, First Transplant group showed a better survival rate (67% vs 43%, odds ratio = 2.60, p = 0.20). Eyes with >3 risk factors had a higher graft failure rate (odds ratio = 5.81, p = 0.003).

CONCLUSION

Survey of the literature suggests that high-risk PKP with concurrent hAM placement demonstrate comparable graft survival. Presence of multiple risk factors is associated with poor survival.

Inhibition of blood vessel formation by a chondrocyte-derived extracellular matrix

In this study, the chondrocyte-derived extracellular matrix (CECM) was evaluated for its activity to inhibit vessel invasion in vitro and in vivo. Human umbilical vein endothelial cells (HUVECs) and rabbit chondrocytes were plated on a bio-membrane made of CECM or human amniotic membrane (HAM). The adhesion, proliferation, and tube formation activity of HUVECs and chondrocytes were examined. The CECM and HAM powders were then mixed individually in Matrigel and injected subcutaneously into nude mice to examine vessel invasion in vivo after 1 week. Finally, a rabbit model of corneal neovascularization (NV) was induced by 3-point sutures in the upper cornea, and CECM and HAM membranes were implanted onto the corneal surface at day 5 after suture injury. The rabbits were sacrificed at 7 days after transplantation and the histopathological analysis was performed. The adhesion and proliferation of HUVECs were more efficient on the HAM than on the CECM membrane. However, chondrocytes on each membrane showed an opposite result being more efficient on the CECM membrane. The vessel invasion in vivo also occurred more deeply and intensively in Matrigel containing HAM than in the one containing CECM. In the rabbit NV model, CECM efficiently inhibited the neovessels formation and histological remodeling in the injured cornea. In summary, our findings suggest that CECM, an integral cartilage ECM composite, shows an inhibitory effect on vessel invasion both in vitro and in vivo, and could be a useful tool in a variety of biological and therapeutic applications including the prevention of neovascularization after cornea injury.

Association of VEGF-A splice variant mRNA expression with outcome in bevacizumab-treated patients with metastatic breast cancer. Clin Breast Cancer. 2014;14:330-338. [PMID: 24703319 DOI: 10.1016/j.clbc.2014.02.009]

BACKGROUND

The prognostic utility of vascular endothelial growth factor A (VEGF-A) splice variants in patients with advanced breast cancer treated with bevacizumab has not been studied.

PATIENTS AND METHODS

A total of 111 patients with metastatic breast cancer treated with weekly docetaxel or ixabepilone without bevacizumab (cohort A) and 100 treated with weekly paclitaxel and bevacizumab (cohort B) were studied. Formalin-fixed tumors were macrodissected for reverse transcription quantitative polymerase chain reaction relative quantification of VEGF-A165, -189, and -206 isoforms spliced at exon 8 proximal splice site (VEGF-Axxxa) and at exon 8 distal splice site (VEGF-Axxxb).

RESULTS

For high VEGF-Axxxa, the hazard ratios (HRs) for progression were 1.08 (P = .71) in non-bevacizumab-treated patients (cohort A) and 0.66 (P = .22) in bevacizumab-treated patients (cohort B), and the HRs for death were 1.45 (P = .13) and 0.50 (P = .049), respectively. The interaction of VEGF-Axxxa with bevacizumab administration was significant (P = .011) for overall survival (OS). High tissue VEGF-Axxxb was not prognostic in cohort A but was predictive for bevacizumab benefit in cohort B (HR for progression, 0.57 [P = .04]; HR for death, 0.51 [P = .02]). Exploratory analyses done only in cohort B suggested that abundance of VEGFR1 messenger RNA (mRNA) in peripheral blood and low VEGFR2 mRNA in tissue correlated with poor outcome. In multivariate analysis, high tissue mRNA of angiogenic VEGF-Axxxa in the presence of bevacizumab therapy predicted for favorable progression-free survival (HR for progression, 0.39; P = .0227) and OS (HR for death, 0.32; P = .0140).

CONCLUSION

Tissue mRNA expression of angiogenic VEGF-Axxxa isoforms was retrospectively associated with adverse prognosis in the absence of bevacizumab and with favorable outcome when bevacizumab was administered in patients with advanced breast cancer.

Macrophages in multiple myeloma

Tumor associated macrophages (TAMs) are a rich source of pro-angiogenic cytokines and growth factors, and a relationship between the TAMs content, the rate of tumor growth and the extent of vascularization has been shown in several tumors. In this article, we have summarized the literature and our data concerning the involvement of TAMs in angiogenesis occurring in multiple myeloma. Finally, therapeutic aspects concerning the potential role of molecules which inhibit macrophage recruitment in the tumor side are also discussed.

Cassaine diterpene alkaloids from Erythrophleum fordii and their anti-angiogenic effect

Angiogenesis plays a critical role in embryonic development and various physiological processes. However, excessive angiogenesis is associated with several pathological conditions including cancer. Angiogenesis is closely related to tumor growth, invasion and metastasis, and is considered a prime target for anticancer therapy. In this study, two new mono cassaine diterpenoid amides (1, 5) and four known compounds (2-4, 6) were isolated from the bark of Erythrophleum fordii (Leguminosae). Their chemical structures were established mainly by 1D and 2D NMR techniques and mass spectrometry. The effects of isolates on endothelial tube formation on Matrigel were investigated. Among them, compound 3 was found to have the most potent inhibitory effect on the capillary-like structure formation of human umbilical vein endothelial cells (HUVECs).

Developments in purification methods for obtaining and evaluation of collagen derived endogenous angioinhibitors

Collagen constitutes one of the vital components of the basement membrane scaffolds. Non-collagenous domains (NC1) derived from collagens exhibit potent anti-angiogenic properties, thus attaining significance in regulation of angiogenesis promoted diseases. Individual NC1 domains essential for anti-angiogenic evaluations are generally obtained through purification of individual non-collagenous domains, which have undergone steady developments for enhancing the yields, purpose of biological evaluations and solubility based on the nature of different NC1 domains. This review focuses on the method developments in obtaining biologically active NC1 domains and for specific evaluations in different scenarios.

Antiangiogenic effects of marine sponge derived compounds on cancer

The term "angiogenic switch" refers to a time-restricted event during tumor progression where the balance between pro- and anti-angiogenic factors, resulting in the transition from dormant avascularized hyperplasia to outgrowing vascularized tumor and eventually to malignant tumor progression. Targeting angiogenesis and its mechanistic pathways are critical target for cancer therapy. Recently, marine derived compounds, plays major role in cancer research. Several sponge derived compounds such as alkaloids, terpenes, macrocylic lactone and polyketide are leading drugs in the treatment of different types of diseases including cancer. Those marine sponge compounds inhibit cancer cell proliferation and tumor angiogenesis. Hence, this review sheds light on angiogenic regulators and marine sponge derived antiangiogenic compounds for cancer.

VEGF111b, a new member of VEGFxxxb isoforms and induced by mitomycin C, inhibits angiogenesis

Vascular endothelial growth factor (VEGF-A) stimulating angiogenesis is required for tumor growth and progression. The conventional VEGF-A isoforms have been considered as pro-angiogenic factors. Another family of VEGF-A isoforms generated by alternative splicing, termed VEGFxxxb isoforms, has anti-angiogenic property, exemplified by VEGF165b. Here, we identify a new number of VEGFxxx family-VEGF111b induced by mitomycin C, although not detected in mitomycin C-unexposed ovarian cancer cells. SKOV3 cells were transfected with pcDNA3.1 empty vector, pcDNA3.1-VEGF111b or pcDNA3.1-VEGF165b to collect conditioned mediums respectively. VEGF111b overexpression inhibits proliferation, migration and tube formation of endothelial cell by inhibiting VEGF-R2 phosphorylation and its downstream signaling, similar to VEGF165b but slightly lower than VEGF165b. The anti-angiogenic property depends on the six amino acids of exon 8b of the VEGFxxxb isoforms. Our results show that VEGF111b is a novel potent anti-angiogenic agent that can target the VEGF-R2 and its signaling pathway to inhibit ovarian tumor growth.

A chorioallantoic membrane model for the determination of anti-angiogenic effects of imatinib

Tumor angiogenesis is of major importance in the growth and metastasis of solid tumors, and the development of anti-angiogenic treatment strategies is thus a relevant option in oncology. The chorioallantoic membrane (CAM) model is a rapid and simple alternative to in vivo studies for the evaluation of anti-angiogenic compounds, thus allowing to reduce animal experiments and, upon establishment of robust and reproducible procedures, to more efficiently and objectively assess the anti-angiogenic efficacy of a given drug. In this paper, we compare two different methods for tumor establishment on a CAM model: (i) a Murine Urothelial Carcinoma (MB49) cell suspension mixed with Matrigel and (ii) an MB49 cell suspension absorbed in Gelfoam gelatin sponges. Based on the applicability of both methods for implant formation, we identify Gelfoam gelatin sponges as superior due to better attachment of the tumors on the membrane surface. For the precise quantitation of tumor xenograft growth and angiogenesis, we furthermore establish in this paper the electronic capturing of the xenografts and the computer-based analysis of the microscopic CAM images in order to determine the number of intersecting vessels and to measure vessel diameters. Beyond its direct effect on tumor cells by inhibiting the tyrosine kinase domain of the abl gene, imatinib has been reported to reduce the Bcr-Abl-mediated secretion of the angiogenesis factor VEGF and hence to interfere with angiogenesis. To test our CAM model for its ability to monitor anti-angiogenic effects, Gelfoam gelatin sponge-based tumor implants were treated by topical application of imatinib at various concentrations. Besides anti-tumor effects, we observed an inhibition of angiogenesis as determined by the number or total diameter of intersecting vessels. We also demonstrate that the calculation of the "blood vessel index" (vessel total diameter/tumor circumference) in our model allows to assess anti-angiogenic effects of imatinib independently of tumor growth inhibition. We conclude that our CAM assay and computer-based analysis represent a useful in vitro technique for the rapid assessment of anti-angiogenic effects of various agents.

Low-dose metronomic chemotherapy: a systematic literature analysis

Low-dose metronomic (LDM) chemotherapy, the frequent and continuous use of low doses of conventional chemotherapeutics, is an emerging alternative to conventional chemotherapy. While promising tumour control rates and excellent safety profiles have been observed, there are no definitive phase III trial results. Furthermore, the selection of patients, drug dosages and dosing intervals is empirical. To systematically review the current state of knowledge regarding LDM chemotherapy, we searched the MEDLINE, EMBASE, CENTRAL and PubMed databases for fully published LDM chemotherapy trials. We calculated the relative dose-intensity (RDI, mg/m(2)/week) of each LDM regimen as compared to conventional maximum tolerated dose (MTD) dosages and the 'dosing-density' (DD, % of days with chemotherapy administration per cycle). Meta-regression was performed to examine factors associated with disease control rate (DCR; complete response (CR)+partial response (PR)+stable disease (SD)). Eighty studies involving mainly pretreated patients with advanced/metastatic breast (26.25%) and prostate (11.25%) cancers were retrieved. The most commonly used drug was cyclophosphamide (43%). LDM chemotherapy was frequently combined with other therapies (64.5%). Response rate (RR) and progression-free survival (PFS) were the most frequent primary end-points (24% and 19%). Mean RR was 26.03% (95% confidence interval (CI): 21.4-30.7), median PFS was 4.6months (interquartile range (IQR): 2.9-7.0) and mean DCR was 56.3% (95% CI: 50.9-61.6). RDI, DD and metronomic drug used were not associated with DCR. Grade 3/4 adverse events were rare (anaemia 7.78%, fatigue 13.4%). Thus, LDM therapy appears to be clinically beneficial and safe in a broad range of tumors. However, meta-regression analysis did not identify predictive factors of response.

A structure-activity relationship study of 1,2,4-triazolo[1,5-a][1,3,5]triazin-5,7-dione and its 5-thioxo analogues on anti-thymidine phosphorylase and associated anti-angiogenic activities

Thirty-three 1,2,4-triazolo[1,5-a][1,3,5]triazin-5,7-dione and its 5-thioxo analogues were designed and synthesized which contained different substituents at meta- and/or para-positions of 2-phenyl or 2-benzyl ring attached to the fused ring structure. The preliminary pharmacological evaluation demonstrated that the 5-thioxo analogues of 1,2,4-triazolo[1,5-a][1,3,5]triazine exhibited a varying degree of inhibitory activity towards thymidine phosphorylase, comparable or better than reference compound, 7-Deazaxanthine (7-DX, 2) (IC50 value = 42.63 μM). Moreover, compounds 5q and 6i displayed a mixed-type of inhibitory mechanism in the presence of variable concentrations of thymidine (dThd). In addition, selected compounds were found to have a noticeable inhibitory effect on the expression of angiogenesis markers, including VEGF and MMP-9 in MDA-MB-231 breast cancer cells.

Deoxypodophyllotoxin exerts both anti-angiogenic and vascular disrupting effects

A functioning vascular supply is essential for solid tumor growth and metastases, which means that blood vessels are an ideal target for antitumor drug discovery. Targeting tumor vasculature involves two main approaches, anti-angiogenesis and vascular disruption. The anti-angiogenic and vascular disrupting activities of deoxypodophyllotoxin (DPT), a natural microtubule destabilizer, were examined with several in vitro, ex vivo and/or in vivo models. First, we demonstrated that DPT significantly inhibits the proliferation, migration and tube formation of endothelial cells and inhibits angiogenesis in rat aortic ring and chick chorioallantoic membrane assays. In further studies, DPT induced cytoskeleton reorganization in endothelial cells, which likely contributed to the anti-angiogenic effect at non-cytotoxic concentrations. DPT treatment at higher concentrations for longer time induced the cell cycle arrest, which may contributes to its anti-proliferation effect and anti-angiogenic activity. And DPT dramatically inducted the expression of cyclin B1 and p21 (WAF1/CIP1). Meanwhile, DPT disrupted capillary-like networks in vitro and newly formed vessels from rat aortic rings. Endothelial cell contraction associated with an increase in F-actin via the Rho/Rho kinase pathway likely contributed to the vascular disrupting activity. Taken together, our results provided the initial evidence that DPT exerts potent anti-angiogenic and vascular disrupting effects. This study also provides important insight into the mechanism of action of promising new anticancer drugs with both anti-angiogenic and vascular disrupting activities.

Advances in research of antiangiogenic drugs for gastric cancer

Gastric cancer is the most common cancer of the digestive system and the first leading cause of cancer deaths in China. Conventional surgery and chemotherapeutic regimens can not significantly improve the poor prognosis of gastric cancer. In recent years, molecular targeted therapy has become a hot topic in the treatment of cancers, and many antiangiogenic drugs for treatment of gastric cancer have been developed, including monoclonal antibodies or soluble receptors that bind and neutralize vascular endothelial growth factor (VEGF), tyrosine kinase receptor inhibitors, and antibodies against VEGF receptors (VEGFRs).

Anti-angiogenesis in hepatocellular carcinoma treatment: current evidence and future perspectives

Hepatocellular carcinoma (HCC) is among the most common cancer diseases worldwide. Arterial hypervascularisation is an essential step for HCC tumorigenesis and can be targeted by transarterial chemoembolization (TACE). This interventional method is the standard treatment for patients with intermediate stage HCC, but is also applied as "bridging" therapy for patients awaiting liver transplantation in many centers worldwide. Usually the devascularization effect induced by TACE is transient, consequently resulting in repeated cycles of TACE every 4-8 wk. Despite documented survival benefits, TACE can also induce the up-regulation of proangiogenic and growth factors, which might contribute to accelerated progression in patients with incomplete response. In 2007, sorafenib, a multi-tyrosine kinase and angiogenesis inhibitor, was approved as the first systemic treatment for advanced stage HCC. Other active targeted compounds, either inhibitors of angiogenesis and/or growth factors, are currently being investigated in numerous clinical trials. To overcome revascularisation or tumor progression under TACE treatment it seems therefore attractive to combine TACE with systemic targeted agents, which might theoretically block the effects of proangiogenic and growth factors. Over the last 12 mo, several retrospective or prospective cohort studies combining TACE and sorafenib have been published. Nevertheless, robust results of the efficacy and tolerability of such combination strategies as proven by randomized, controlled trials are awaited in the next two years.

Inhibitory effects of corni fructus extract on angiogenesis and adipogenesis

Natural products in Chonnam, Korea were screened via anti-angiogenesis experiments, and 1 candidate product was identified, Corni fructus, which exerted dose-dependent inhibitory effects against angiogenesis, adipogenesis, and cell adhesion. C. fructus extract (CFE) exhibits an angiogenesis inhibitory effect superior to that of the EGCG from green tea leaves. The expression level of angiogenesis and adipogenesis-related signal molecules in the western blotting was reduced by increasing the amount of added CFE. Moreover, a diet supplemented with CFE was deemed more effective in inducing weight loss in LB mice than a representative synthetic diet drug, orlistat, which incidently caused the side effect of denuding the mice of their hair. These results indicate that C. fructus may prove to be a useful anti-adipogenic compound, and these in vitro results may be reflected later under in vivo conditions.

Recombinant attenuated Salmonella typhimurium vaccine SL3261-pcDNA3.1+/flk-1(n1-4) inhibits growth of colorectal cancer in BALB/c mice

AIM: To investigate the inhibitory effect of extracellular 1-4 segments of VEGFR2 on tumor growth.

METHODS: Oral DNA vaccine SL3261-pcDNA3.1+/flk-1_(n1-4) was developed and BALB/c mice were immunized with vaccine encoding flk-1_(n1-4) via gastrogavage. BALB/c mice receiving SL3261-pcDNA3.1+ or 10% NaHCO3 via gastrogavage were used as vector control and NaHCO3 group. Serum levels of VEGF and specific anti-flk-1_(n1-4)-IgG antibody were measured by ELISA. The subset of lympholeukocytes was analyzed by flow cytometry. Mouse models of CT-26 adencarcinoma of colon were treated with SL3261-pcDNA3.1+/flk-1_(n1-4) through gastrogavage. Tumor diameter and weight were measured, microvessel density (MVD) in the tumor tissue was detected by immunohistochemistry, and the survival time of mice was also investigated.

RESULTS: The serum level of VEGF in the vaccine group was significantly lower than that in the control group. All mice immunized with the DNA vaccine had a high level of anti-flk-1_(n1-4)-IgG, and showed strong activities against flk-1_(n1-4). After inoculation of CT-26 cells, the number of CD4⁺ T and CD8⁺ T cells was obviously greater in the vaccine group than in the control group. Tumor weight and diameter as well as MVD were significantly lower in the vaccine group than in the vector and NaHCO₃ control groups (3.64 ± 1.34 g vs 8.40 ± 0.66 g, 8.26 ± 0.44 g; 2.62 ± 0.54 mm³vs 6.01 ± 0.14 mm³, 5.92 ± 0.25 mm³; 2.06 ± 1.02 vs 6.93 ± 2.34, 7.34 ± 4.12; P < 0.05). The survival time of mice was longer in the vaccine group than in the control group.

CONCLUSION: The extracellular 1-4 segments of VEGFR2 can inhibit the growth of tumor by suppressing the growth of its endothelial cells.

Synergistic anti-tumor effect of recombinant chicken fibroblast growth factor receptor-1-mediated anti-angiogenesis and low-dose gemcitabine in a mouse colon adenocarcinoma model

AIM: To evaluate whether the combination of recom-binant chicken fibroblast growth factor receptor -1 (FGFR-1) protein vaccine (cFR-1) combined with low-dose gemcitabine would improve anti-tumor efficacy in a mouse CT26 colon adenocarcinoma (CT26) model.

METHODS: The CT26 model was established in BABL/c mice. Seven days after tumor cell injection, mice were randomly divided into four groups: combination therapy, cFR-1 alone, gemcitabine alone, and normal saline groups. Tumor growth, survival rate of tumor-bearing mice, and systemic toxicity were observed. The presence of anti-tumor auto-antibodies was detected by Western blot analysis and enzyme-linked immunospot assay, microvessel density (MVD) of the tumors and tumor cell proliferation were detected by Immunohistochemistry staining, and tumor cell apoptosis was detected by TdT-mediated biotinylated-dUTP nick end label staining.

RESULTS: The combination therapy results in apparent decreases in tumor volume, microvessel density and tumor cell proliferation, and an increase in apoptosis without obvious side-effects as compared with either therapy alone or normal control groups. Also, both auto-antibodies and the antibody-producing B cells against mouse FGFR-1 were detected in mice immunized with cFR-1 vaccine alone or with combination therapy, but not in non-immunized mice. In addition, the deposition of auto-antibodies on endothelial cells from mice immunized with cFR-1 was observed by immunofluorescent stain-ing, but not on endothelial cells from control groups. Synergistic indexes of tumor volume, MVD, cell apoptosis and proliferation in the combination therapy group were 1.71 vs 1.15 vs 1.11 and 1.04, respectively, 31 d after tumor cell injection.

CONCLUSION: The combination of cFR-1-mediated anti-angiogenesis and low-dose gemcitabine synergistically enhances the anti-tumor activity without overt toxicity in mice.

Cancer gene therapy targeting angiogenesis: An updated Review

Since the relationship between angiogenesis and tumor growth was established by Folkman in 1971, scientists have made efforts exploring the possibilities in treating cancer by targeting angiogenesis. Inhibition of angiogenesis growth factors and administration of angiogenesis inhibitors are the basics of anti-angiogenesis therapy. Transfer of anti-angiogenesis genes has received attention recently not only because of the advancement of recombinant vectors, but also because of the localized and sustained expression of therapeutic gene product inside the tumor after gene transfer. This review provides the up-to-date information about the strategies and the vectors studied in the field of anti-angiogenesis cancer gene therapy.