Potent Antiangiogenic Activity Research Articles

Beta-blocker usage after malignant melanoma diagnosis and survival: a population-based nested case-control study

Beta-blockers have potential antiangiogenic and antimigratory activity. Studies have demonstrated a survival benefit in patients with malignant melanoma treated with beta-blockers. To investigate the association between postdiagnostic beta-blocker usage and risk of melanoma-specific mortality in a population-based cohort of patients with malignant melanoma. Patients with incident malignant melanoma diagnosed between 1998 and 2010 were identified within the U.K. Clinical Practice Research Datalink and confirmed using cancer registry data. Patients with malignant melanoma with a melanoma-specific death (cases) recorded by the Office of National Statistics were matched on year of diagnosis, age and sex to four malignant melanoma controls (who lived at least as long after diagnosis as their matched case). A nested case-control approach was used to investigate the association between postdiagnostic beta-blocker usage and melanoma-specific death and all-cause mortality. Conditional logistic regression was applied to generate odds ratios (ORs) and 95% confidence intervals (CIs) for beta-blocker use determined from general practitioner prescribing. Beta-blocker medications were prescribed after malignant melanoma diagnosis to 20·2% of 242 patients who died from malignant melanoma (cases) and 20·3% of 886 matched controls. Consequently, there was no association between beta-blocker use postdiagnosis and cancer-specific death (OR 0·99, 95% CI 0·68-1·42), which did not markedly alter after adjustment for confounders including stage (OR 0·87, 95% CI 0·56-1·34). No significant associations were detected for individual beta-blocker types, by defined daily doses of use or for all-cause mortality. Contrary to some previous studies, beta-blocker use after malignant melanoma diagnosis was not associated with reduced risk of death from melanoma in this U.K. population-based study.

GABARBP down-regulates HIF-1α expression through the VEGFR-2 and PI3K/mTOR/4E-BP1 pathways

Human γ-aminobutyrate type A (GABAA) receptor-binding protein (GABARBP), a tumor suppressor protein with apoptotic function, can be inhibited in response to angiogenesis through the PI3K/Akt signaling cascades. Here, we investigated whether GABARBP over-expression could regulate vascular endothelial growth factor (VEGF)/hypoxia-inducible factor-1α (HIF-1α) expression and angiogenic activity in a carcinoma model system. GABARBP dramatically inhibited VEGF-induced endothelial cell proliferation, migration, and tube formation, as well as VEGFR-2 phosphorylation in vitro. At the same time, GABARBP exposed potent anti-angiogenic activity and remarkably down-regulated the levels of VEGF and HIF-1α protein expression, key components for angiogenesis. In addressing its biological molecular mechanism, GABARBP was found to effectively inhibit the phosphorylation of down-stream PI3K components, such as PDK1, Akt, mTOR, TSC-2, p70S6K, and 4E-BP1 by directly binding with VEGFR-2. In contrast, p38/JNK phosphorylation was not suppressed by GABARBP. These findings disclose a novel function of GABARBP in suppressing VEGF and HIF-1α protein expression, which is important for tumor angiogenesis and tumor growth. Thus, our data strongly provides novel biological mechanistic insights into the regulatory function of GABARBP in ovarian tumor progression, and the important of pre-clinical certification of GABARBP as a potential angiogenesis agent targeting ovarian tumorigenesis.

RETRACTED ARTICLE:Type IV collagen α1-chain noncollagenous domain blocks MMP-2 activation both in-vitro and in-vivo

α1(IV)NC1 inhibits angiogenesis by regulating MAPK activation, this biological function was partly attributed α1(IV)NC1 binding to α1β1-integrin. However, its potent antiangiogenic activity and the molecular targets of α1(IV)NC1 has not been investigated. In the present study, the regulation of MMP-2 activation by α1(IV)NC1 was evaluated. α1β1-integrin which is required for inhibition of angiogenesis is not playing a role in cellular invasion and inhibition of MMP-2 activation by α1(IV)NC1. We found that α1(IV)NC1 binds the CBD of MMP-2 and forming a stable complex that prevents activation of MMP-2. The antiangiogenic activity of α1(IV)NC1 is mediated, in part, by this binding activity. In addition, up-regulation of TIMP-2 by α1(IV)NC1 led to saturation of MT1-MMP binding sites, which in turn led to inhibition of MMP-2 activation. In-vivo studies using α1-integrin null-mice treated with higher doses of α1(IV)NC1 showed integrin independent inhibition of tumor growth and active-MMP-2, without affecting MMP-9, MMP-7 and angiostatin.

Oleanolic acid and its synthetic derivatives for the prevention and therapy of cancer: Preclinical and clinical evidence

Oleanolic acid (OA, 3β-hydroxyolean-12-en-28-oic acid) is a ubiquitous pentacyclic multifunctional triterpenoid, widely found in several dietary and medicinal plants. Natural and synthetic OA derivatives can modulate multiple signaling pathways including nuclear factor-κB, AKT, signal transducer and activator of transcription 3, mammalian target of rapamycin, caspases, intercellular adhesion molecule 1, vascular endothelial growth factor, and poly (ADP-ribose) polymerase in a variety of tumor cells. Importantly, synthetic derivative of OA, 2-cyano-3,12-dioxoolean-1,9-dien-28-oic acid (CDDO), and its C-28 methyl ester (CDDO-Me) and C28 imidazole (CDDO-Im) have demonstrated potent antiangiogenic and antitumor activities in rodent cancer models. These agents are presently under evaluation in phase I studies in cancer patients. This review summarizes the diverse molecular targets of OA and its derivatives and also provides clear evidence on their promising potential in preclinical and clinical situations.

A C-terminal fragment of fibulin-7 interacts with endothelial cells and inhibits their tube formation in culture

We have previously demonstrated that fibulin-7 (Fbln7) is expressed in teeth by pre-odontoblast and odontoblast cells, localized in the basement membrane and dentin matrices, and is an adhesion molecule for dental mesenchyme cells and odontoblasts. Fbln7 is also expressed in blood vessels by endothelial cells. In this report, we show that a recombinant C-terminal Fbln7 fragment (Fbln7-C) bound to Human Umbilical Vein Endothelial Cells (HUVECs) but did not promote cell spreading and actin stress fiber formation. Fbln7-C binding to HUVECs induced integrin clustering at cell adhesion sites with other focal adhesion molecules, and sustained activation of FAK, p130Cas, and Rac1. In addition, RhoA activation was inhibited, thereby preventing HUVEC spreading. As endothelial cell spreading is an important step for angiogenesis, we examined the effect of Fbln7-C on angiogenesis using in vitro assays for endothelial cell tube formation and vessel sprouting from aortic rings. We found that Fbln7-C inhibited the HUVEC tube formation and the vessel sprouting in aortic ring assays. Our findings suggest potential anti-angiogenic activity of the Fbln7 C-terminal region.

Multiple microRNAs Derived from Chemically Synthesized Precursors Regulate Thrombospondin 1 Expression

Thrombospondin 1 (THBS1) is a secreted protein with a variety of biological functions, including a potent anti-angiogenic activity and activation of latent transforming growth factor beta (TGF-β). In many human cancers it is expressed at low levels, although mutations in the THBS1 gene have been rarely reported. Instead, the loss of THBS1 expression has been proposed to be due to transcriptional and post-transcriptional deregulations. In a systematic screen of predicted microRNA (miRNA) binding sites in the THBS1 3' untranslated region (UTR) we employed chemically synthesized pre-miRNAs-a new class of pre-miRNA mimics-to show that several miRNAs (let-7a, miR-18a, miR-29b, miR-194, and miR-221) can modulate THBS1 expression at the post-transcriptional level. Sequence-specific downregulation of THBS1 by let-7a, miR-18a or by a small interfering RNA induced TGF-β1 and SMAD4 transcript levels. Ectopic expression of latent TGF-β1 reduced THBS1 protein expression and was associated with increased expression of let-7a, let-7-b, and miR-18a in cells. These data suggest an inverse correlation of THBS1 and latent TGF-β1 expression levels possibly involving miRNAs.

Molecular Targets of Honokiol: A Promising Phytochemical for Effective Cancer Management.

Honokiol is a bioactive, biphenolic phytochemical, present in the aerial parts of plants classified under the genus Magnolia. It has been an important constituent of Asian traditional medicine and is used against many ailments. Honokiol possesses potent antioxidative, anti-inflammatory, antiangiogenic, and anticancer activities by targeting a variety of signaling molecules. Consequently, there has been immense interest in exploring its utility as a novel chemopreventive and therapeutic agent against several malignancies. In this chapter, we review the structure-function relationship of honokiol and its derivative compounds, the impact of honokiol on various phenotypes associated with cancer progression and metastasis, and its prominent molecular targets and pharmacokinetics. Clearly, the available data generate significant interest in this novel phytochemical and emerging information continues to provide strong support for its potential applicability in cancer management.

Reversible Action of Diaminothiazoles in Cancer Cells Is Implicated by the Induction of a Fast Conformational Change of Tubulin and Suppression of Microtubule Dynamics

Diaminothiazoles are novel cytotoxic compounds that have shown efficacy toward different cancer cell lines. They show potent antimitotic and antiangiogenic activity upon binding to the colchicine-binding site of tubulin. However, the mechanism of action of diaminothiazoles at the molecular level is not known. Here, we show a reversible binding to tubulin with a fast conformational change that allows the lead diaminothiazole DAT1 [4-amino-5-benzoyl-2-(4-methoxy phenyl amino)thiazole] to cause a reversible mitotic block. DAT1 also suppresses microtubule dynamic instability at much lower concentration than its IC(50) value in cancer cells. Both growth and shortening events were reduced by DAT1 in a concentration-dependent way. Colchicine, the long-studied tubulin-binding drug, has previously failed in the treatment of cancer due to its toxicity, even though it generates a strong apoptotic response. The toxicity is attributable to its slow removal from the cell due to irreversible tubulin binding caused by a slow conformational change. DAT1 binds to tubulin at an optimal pH lower than colchicine. Tubulin conformational studies showed that the binding environments of DAT1 and colchicine are different. Molecular dynamic simulations showed a difference in the number of H-bonding interactions that accounts for the different pH optima. This study gives an insight of the action of compounds targeting tubulin's colchicine-binding site, as many such compounds have entered into clinical trials recently.

Suppression of VEGF expression through interruption of the HIF-1α and Akt signaling cascade modulates the anti-angiogenic activity of DAPK in ovarian carcinoma cells

Death-associated protein kinase (DAPK) plays an important role in apoptosis regulation and has been shown to maintain antitumor and metastasis suppressor properties. In the present study, we investigated whether DAPK overexpression may mediate vascular endothelial growth factor (VEGF)/hypoxia-inducible factor-1α (HIF-1α) expression and angiogenic activity in the human carcinoma cell model system. VEGF plays a pivotal role in tumor angiogenesis and tumorigenesis. We found that DAPK significantly downregulated VEGF-induced endothelial cell proliferation, migration and tube formation as well as VEGF receptor-2 (VEGFR-2) phosphorylation in vitro. In addition, DAPK exhibited potent anti-angiogenic activity and clearly decreased the levels of VEGF and HIF-1α expression, a key regulator for angiogenesis. Notably, our results strongly indicated that DAPK can disturb VEGFR-2 transcriptional activity by inhibiting VEGFR-2 phosphorylation through the PI3K/Akt signaling cascade. Collectively, our study identified a novel function of DAPK in regulating cellular VEGF/HIF-1α activity during tumorigenesis, which may act together with its anti-angiogenic function to inhibit tumor progression.

The antiangiogenic activities of ethanolic crude extracts of four Salvia species

BackgroundAngiogenesis is one of cancer hallmarks that are required for both cancer progression and metastasis. In this study we examined the antiangiogenic properties of the ethanolic crude extracts of four Salvia species grown in Jordan.MethodsThe direct antiangiogenic activity was evaluated using various models: ex vivo rat aortic ring assay, in vitro assessment of HUVEC proliferation and migration, and in vivo CAM assay, while we used the changes in the expression of HIF-1α and VEGF in breast cancer cells (MCF 7) as an indicative for the indirect antiangiogenic activity.ResultsAll four crude extracts showed a potential antiangiogenic activity in the rat aortic assay, however two species were found to be cytotoxic against Fibroblast cell line (PLF); the finding that caused the exclusion of these two extracts from further studies. Of the two remaining extracts, S. triloba showed very promising direct and indirect antiangiogenic activities. S. triloba inhibited the HUVEC proliferation with an IC50 of 90 μg/mL and HUVEC migration by 82% at 150 μg/mL. Furthermore, the in vivo CAM assay also illustrated the high impact of S. triloba against the newly formed vessel in the chicken embryonic membrane. Interestingly, the S. triloba inhibited the expression of VEGF at the mRNA and protein and the HIF-1α mRNA in the MCF 7 breast cancer cells under both normoxic and hypoxic conditions.ConclusionsTaken together, all these findings of the direct and indirect angiogenic investigations nominated S. triloba as a highly potent antiangiogenic plant that may have chemotherapeutic and/or chemoprevention potentials.

CUDC-907, a Dual HDAC and PI3K Inhibitor, Potentially Targets Cancer Cells and The Microenvironment In Hematological Malignancies

Histone deacetylase (HDAC) and phosphatidylinositol 3-kinase (PI3K) inhibitors have each emerged as promising anti-cancer therapeutics that may target not only cancer cells but also their microenvironment. We have developed a strategy to simultaneously inhibit HDAC- and PI3K-dependent signaling with a single small molecule, CUDC-907. In this study, we report that CUDC-907 induces apoptosis and G2/M arrest in hematological cancer cells. CUDC-907 also impairs cytokine and chemokine production, in association with inhibition of AKT and STAT phosphorylation. Moreover, we demonstrate that CUDC-907 reduces hypoxia-induced HIF-1a expression in cancer cells and VEGF-induced tube formation in endothelial cells, suggesting potential anti-angiogenic activity. With its integrated HDAC and PI3K inhibitory activity, CUDC-907 may thus offer improved therapeutic benefit through simultaneous suppression of cancer cell proliferation and perturbation of their protective microenvironment. These studies provide support for the clinical development of CUDC-907 in hematological malignancies. A Phase I study in patients with lymphoma or multiple myeloma is ongoing. Disclosures:Wang:Curis Inc.: Employment. Pursell:Curis Inc.: Employment. Ma:Curis Inc.: Employment. Atoyan:Curis Inc.: Employment. Samson:Curis Inc.: Employment. Borek:Curis Inc.: Employment. DellaRocca:Curis Inc.: Employment. Yin:Curis Inc.: Employment. Wang:Curis Inc.: Employment. Zifcak:Curis Inc.: Employment. Xu:Curis Inc.: Employment. Voi:Curis Inc.: Employment. Lai:Curis Inc.: Employment.

Inhibitory effects of quercetin on angiogenesis in larval zebrafish and human umbilical vein endothelial cells

Angiogenesis plays an essential role in many physiological and pathological processes. Quercetin, a plant pigment and traditional Chinese medicinal herb, is an important flavonoid that has anti-cancer activity. However, the function of quercetin in blood vessel development in vivo and in vitro is still unclear. In this study, we investigated the anti-angiogenic activity of quercetin in zebrafish embryos and in human umbilical vein endothelial cells (HUVECs). Our results showed that quercetin disrupted the formation of intersegmental vessels, the dorsal aorta and the posterior cardinal vein in transgenic zebrafish embryos. In HUVECs, quercetin inhibited cell viability, the expression of vascular endothelial growth factor receptor 2 and tube formation in a dose-dependent manner. In inhibiting angiogenesis, quercetin was found to be involved in suppressing the extracellular signal-regulated kinase signaling pathway in vivo and in vitro. This study has shown that quercetin has potent anti-angiogenic activity and may be a candidate anti-cancer agent for future research.

Ritonavir inhibits HIF-1α-mediated VEGF expression in retinal pigment epithelial cells in vitro

Retinal hypoxia-mediated activation of the hypoxia-inducible factor (HIF pathway) leading to angiogenesis is a major signaling mechanism underlying a number of sight-threatening diseases. Inhibiting this signaling mechanism with an already approved therapeutic molecule may have promising anti-angiogenic role with fewer side effects. Hence, the primary objective of this study was to examine the expression of HIF-1α and VEGF in human retinal pigment epithelial cells treated with ritonavir under hypoxic and normoxic conditions. ARPE-19 and D407 cells were cultured in normoxic or hypoxic conditions, alone or in the presence of ritonavir. Quantitative real-time polymerase chain reaction, immunoblot analysis, sandwich ELISA, endothelial cell proliferation, and cytotoxicity were performed. A 12-h hypoxic exposure resulted in elevated mRNA expression levels of both HIF-1α and VEGF in ARPE-19 and D407 cells. Hence, this time point was selected for subsequent experiments. Presence of ritonavir in the culture medium strongly inhibited VEGF expression in a concentration-dependent manner under hypoxic conditions. Immunoblot analysis demonstrated a substantially reduced protein expression of HIF-1α in the presence of ritonavir. Further, hypoxic exposure-induced VEGF secretion was also inhibited by ritonavir, as demonstrated using ELISA. Finally, ritonavir significantly diminished the proliferation of choroid-retinal endothelial (RF/6A) cells demonstrating potential anti-angiogenic activity. Cytotoxicity studies showed that ritonavir is non-toxic to RPE cells. This study demonstrates for the first time that ritonavir can inhibit HIF-1α and VEGF in ARPE-19 and D407 cells. Such inhibition may form a platform for application of ritonavir in the treatment of various ocular diseases.

Improvement of anti-inflammatory and anti-angiogenic activity of berberine by novel rapid dissolving nanoemulsifying technique

Berberine, an isoquinoline alkaloid, has wide biological and pharmacological actions. Despite the promising pharmacological effects and safety of berberine, poor oral absorption due to its extremely low aqueous solubility results in poor oral systemic bioavailability. This limits its clinical usage. This study describes the development and characterization of self-nanoemulsifying drug delivery system (SNEDDS) of berberine in liquid as well as solid form with improved solubility, dissolution and in vivo therapeutic efficacy. The SNEDDS of berberine were prepared using Acrysol K-150, Capmul MCM and polyethylene glycol 400. The formulations were characterized for various in vitro physicochemical characteristics. In vivo efficacy was evaluated in acetic acid induced inflammatory bowel model in rats. Anti-angiogenic activity of the developed SNEDDS of berberine was studied using chick chorioallantoic membrane assay. SNEDDS of berberine rapidly formed nanoemulsions with globule size of 17–45nm. The in vitro rate and extent of release of berberine from SNEDDS was significantly higher than berberine alone. Chick chorioallantoic membrane assay revealed potent anti-angiogenic activity of SNEDDS of berberine. These studies demonstrate that the SNEDDS of berberine is a promising strategy for improving its therapeutic efficacy and have potential application in the treatment of chronic inflammatory conditions and cancer.

In vitro effects of vitamin supplements on platelet-activating factor and its metabolism in age-related macular degeneration

Objective: The purpose of our study was to investigate for the first time a series of vitamin supplements used for age-related macular degeneration (AMD) as potential inhibitors of platelet-activating factor (PAF).Materials and methods: Various vitamin supplements were tested in washed rabbit platelets (WRPs), in order to investigate the interaction between vitamin supplements (InShape, Nutrof, Ocuvite, Vitalux) and inhibition of PAF-induced platelet aggregation. Additionally, we examined their ability to affect PAF-metabolism, through their in vitro effect on PAF basic metabolic enzymes (PAF-CPT, lyso PAF-AT, and PAF-AH).Results: Nutrof exhibited the strongest anti-PAF activity, while Vitalux was the most potent anti-inflammatory factor.Conclusion: This is the first study to bring in surface potent anti-inflammatory and anti-angiogenic activities of some vitamin supplements used against AMD, through their in vitro anti-PAF effects in WRPs and the rabbit plasma and leukocyte PAF metabolism, suggesting a promising role of vitamin supplements and especially resveratrol, concerning its potent anti-angiogenic activity in AMD.

Isogambogenic acid inhibits tumour angiogenesis by suppressing Rho GTPases and vascular endothelial growth factor receptor 2 signalling pathway

Isogambogenic acid (iso-GNA) is a well-known herbal medicine extracted from Garcinia hanburyi. Although it is thought to have anti-tumour effects, its function is still unknown. This study carried out in vitro and in vivo evaluations of the anti-tumour and anti-angiogenic activity of iso-GNA and underlying mechanisms. A standard methyl thiazolyl tetrazolium assay showed that iso-GNA was more effective in inhibiting the proliferation of human umbilical vascular endothelial cells than A549 cancer cells. Iso-GNA demonstrated potent anti-angiogenic activity and low toxicity at appropriate concentrations in zebrafish embryos. In a xenograft nude mouse model of lung tumour, iso-GNA effectively inhibited tumour growth and tumour angiogenesis. Iso-GNA suppressed neovascularization of implanted matrigel plugs in vivo and inhibited vascular endothelial growth factor (VEGF)-induced microvessel sprouting from mouse aortic rings ex vivo. Iso-GNA inhibited VEGF-induced migration, invasion, and tube formation in vitro and affected cytoskeletal rearrangement in human umbilical vascular endothelial cells. The results show that iso-GNA suppressed angiogenesis-mediated tumour growth by targeting VEGFR2, Akt, mitogen-activated protein kinase, Rho GTPase, vascular endothelium-cadherin, and focal adhesion kinase signalling pathways. Together, these data suggest that iso-GNA inhibits angiogenesis and may be a viable drug candidate in anti-angiogenesis and anti-cancer therapies.

In vitro antimetastatic effect of phosphatidylinositol 3-kinase inhibitor ZSTK474 on prostate cancer PC3 cells.

Tumor metastasis is the main cause of lethality of prostate cancer, because conventional therapies like surgery and hormone treatment rarely work at this stage. Tumor cell migration, invasion and adhesion are necessary processes for metastasis. By providing nutrition and an escape route from the primary site, angiogenesis is also required for tumor metastasis. Phosphatidylinositol 3-kinases (PI3Ks) are well known to play important roles in tumorigenesis as well as metastasis. ZSTK474 is a specific PI3K inhibitor developed for solid tumor therapy. In the present report, antimetastatic activities of ZSTK474 were investigated in vitro by determining the effects on the main metastatic processes. ZSTK474 exhibited inhibitory effects on migration, invasion and adhesive ability of prostate cancer PC3 cells. Furthermore, ZSTK474 inhibited phosphorylation of Akt substrate-Girdin, and the secretion of matrix metalloproteinase (MMP), both of which were reported to be closely involved in migration and invasion. On the other hand, ZSTK474 inhibited the expression of HIF-1α and the secretion of vascular endothelial growth factor (VEGF), suggesting its potential antiangiogenic activity on PC3 cells. Moreover, we demonstrated the antiangiogenesis by determining the effect of ZSTK474-reduced VEGF on tube formation of human umbilical vein endothelial cells (HUVECs). In conclusion, ZSTK474 was demonstrated to have potential in vitro antimetastatic effects on PC3 cells via dual mechanisms: inhibition of metastatic processes including cell migration, invasion and adhesion, and antiangiogenesis via blockade of VEGF secretion.

MiR‐492 impairs the angiogenic potential of endothelial cells

Endothelial cells growing in high glucose-containing medium show reduced cell proliferation and in vitro angiogenesis. Evidence suggests that the molecular pathways leading to these cellular responses are controlled by microRNAs, endogenous post-transcriptional regulators of gene expression. To identify the microRNAs and their targeted genes involved in the glucose responses, we performed the miRNA signature of Human Umbelical Vein Endothelial Cells (HUVECs) exposed and unexposed to high glucose. Among differentially expressed microRNAs, we analysed miR-492 and showed that its overexpression was able to reduce proliferation, migration and tube formation of HUVEC. These effects were accompanied by the down-regulation of eNOS, a key regulator of the endothelial cell function. We showed that eNOS was indirectly down-regulated by miR-492 and we discovered that miR-492 was able to bind mRNAs involved in proliferation, migration, tube formation and regulation of eNOS activity and expression. Moreover, we found that miR-492 decreased VEGF expression in HUVEC and impaired in vivo angiogenesis in a tumour xenograft model, suggesting a role also in modulating the secretion of pro-angiogenic factors. Taken together, the data indicate that miR-492 exerts a potent anti-angiogenic activity in endothelial cells and therefore miR-492 seems a promising tool for anti-angiogenic therapy.

Multiple FAS1 domains and the RGD motif of TGFBI act cooperatively to bind αvβ3 integrin, leading to anti-angiogenic and anti-tumor effects

TGFBI, a transforming growth factor β-induced extracellular matrix protein, circulates at a level of ~300ng/ml in humans and modulates several integrin-mediated cellular functions. The protein contains an N-terminal EMI domain, four consecutive FAS1 domains, and the RGD motif. Each FAS1 domain and the RGD motif have been known to interact with avb3 integrin. Here, we found that the binding affinity (Kd) of TGFBI for αvβ3 integrin was approximately 3.8×10−8M, a value ~2300-fold higher than that of a single FAS1 domain, and demonstrated that this greater affinity was due to the cooperative action of the four FAS1 domains and the RGD motif. Moreover, TGFBI exhibited more potent anti-angiogenic and anti-tumorigenic activities, even at a 100-fold lower molar dose than the reported effective dose of the FAS1 domain. Finally, our data showed that TGFBI specifically targeted the tumor vasculature and accumulated at the tumor site. Collectively, our results support the theory that TGFBI acts as a potent endogenous anti-tumor and anti-angiogenic molecule by targeting αvβ3 integrin, and highlights the importance of physiological circulating TGFBI levels in inhibiting tumor growth.

Anti-angiogenic activity of salvicine

Context: Salvicine is a pharmacologically active derivative from Chinese medicinal plant Salvia prionitis Hance (Labiatae). It has been reported that salvicine inactivates β1 integrin and inhibits integrin-mediated cell adhesion to fibronectin. Given the emerging correlation between integrins and angiogenesis, we propose that salvicine abolishes cell adhesion and subsequent metastasis by inhibiting angiogenisis.Objective: The anti-angiogenesis activities of salvicine were investigated for the first time.Materials and methods: The cytotoxicity of salvicine on human microvascular endothelial cells (HMECs) and non-small cell lung adenocarcinoma A549 cells were measured at doses between 0.625 and 200 µM. Changes of cell migration were detected with doses of salvicine at 1.25–5 µM, and basement membrane matrigel matrix was used for the assessment of tube formation at concentrations ranging from 0.078 to 1.25 µM. In addition, mRNA expression of basic fibroblast growth factor (bFGF) in A549 cells was studied with the RT-PCR assay.Results: In vitro studies revealed that the IC50 of salvicine on A549 cells (18.66 µM) was two-fold higher than that of HMECs (7.91 µM). Salvicine (1.25, 2.5 and 5.0 μM) inhibited significantly the endothelial cell migration up to 56, 73 and 82%, respectively. Salvicine decreased capillary-like tube formation of HMECs with high potency. Furthermore, it (30 µM) markedly reduced the mRNA expression of bFGF in A549 cells, while vascular endothelial growth factor (VEGF) mRNA expression remained unchanged.Discussion and conclusion: Our results suggest that salvicine has potent anti-angiogenic activity through the inhibition on the sequential angiogenic cascades: proliferation, migration and tube formation and is associated with influence on the expression of bFGF of tumor cell.