Inhibited Human Umbilical Vein Endothelial Cells Proliferation Research Articles

Knockdown of MALAT1 expression inhibits HUVEC proliferation by upregulation of miR-320a and downregulation of FOXM1 expression.

Regulation of cancer angiogenesis could be a useful strategy in cancer therapy. Metastasis-associated lung adenocarcinoma transcript 1 (MALAT1) is a long non-coding RNA (lncRNA), and can induce cancer cell proliferation, while lncRNAs, generally are able to act as microRNA (miRNA) sponges. The latter is a type of competitive endogenous RNA (ceRNA) that regulates expression of the targeting miRNAs and protein-coding genes. This study investigated the proliferative role of MALAT1 in human umbilical vein endothelial cells (HUVECs) and the underlying molecular events. The data showed that knockdown of MALAT1 expression using MALAT1 siRNA inhibited HUVEC proliferation and also significantly decreased levels of FOXM1 mRNA and protein in vitro, while knockdown of FOXM1 expression reduced HUVEC proliferation. Annotation of HUVEC microarray data revealed that seven miRNAs, including miR-320a, were upregulated after knockdown of MALAT1 expression in HUVECs. MALAT1 was shown to reciprocally interact with miR-320a, i.e., expression of one negatively regulated levels of the other, whereas knockdown of MALAT1 expression promoted miR-320a levels. Furthermore, miR-320a could directly target and inhibit FOXM1 expression in HUVECs. Knockdown of MALAT1 expression enhanced miR-320a expression but reduced FOXM1 expression resulting in downregulation of HUVEC proliferation. However, such an effect was inhibited by miR-320a depletion. In conclusion, this study demonstrates that miR-320a plays an important role in mediating the effects of MALAT1 on HUVEC proliferation by suppression of FOXM1 expression. Thus, targeting of this gene pathway could be a novel strategy in cancer therapy.

Preparation of arginine-glycine-aspartic acid-modified biopolymeric nanoparticles containing epigalloccatechin-3-gallate for targeting vascular endothelial cells to inhibit corneal neovascularization.

Neovascularization (NV) of the cornea can disrupt visual function, causing ocular diseases, including blindness. Therefore, treatment of corneal NV has a high public health impact. Epigalloccatechin-3-gallate (EGCG), presenting antiangiogenesis effects, was chosen as an inhibitor to treat human vascular endothelial cells for corneal NV treatment. An arginine–glycine–aspartic acid (RGD) peptide–hyaluronic acid (HA)-conjugated complex coating on the gelatin/EGCG self-assembly nanoparticles (GEH-RGD NPs) was synthesized for targeting the αvβ3 integrin on human umbilical vein endothelial cells (HUVECs) in this study, and a corneal NV mouse model was used to evaluate the therapeutic effect of this nanomedicine used as eyedrops. HA-RGD conjugation via COOH and amine groups was confirmed by 1H-nuclear magnetic resonance and Fourier-transform infrared spectroscopy. The average diameter of GEH-RGD NPs was 168.87±22.5 nm with positive charge (19.7±2 mV), with an EGCG-loading efficiency up to 95%. Images of GEH-RGD NPs acquired from transmission electron microscopy showed a spherical shape and shell structure of about 200 nm. A slow-release pattern was observed in the nanoformulation at about 30% after 30 hours. Surface plasmon resonance confirmed that GEH-RGD NPs specifically bound to the integrin αvβ3. In vitro cell-viability assay showed that GEH-RGD efficiently inhibited HUVEC proliferation at low EGCG concentrations (20 μg/mL) when compared with EGCG or non-RGD-modified NPs. Furthermore, GEH-RGD NPs significantly inhibited HUVEC migration down to 58%, lasting for 24 hours. In the corneal NV mouse model, fewer and thinner vessels were observed in the alkali-burned cornea after treatment with GEH-RGD NP eyedrops. Overall, this study indicates that GEH-RGD NPs were successfully developed and synthesized as an inhibitor of vascular endothelial cells with specific targeting capacity. Moreover, they can be used in eyedrops to inhibit angiogenesis in corneal NV mice.

Abstract 3257: The impact of dual targeting VEGFR2 and Tie-2 on angiogenesis using in vitro model

Abstract Angiogenesis is an essential key process in tumor growth, invasion, and metastasis. Several angiogenesis inhibitors have been clinically proven to treat a wide variety of cancer types. These agents target either the vascular endothelial growth factor (VEGF) or the intracellular tyrosine kinase domain of VEGF receptors. Despite the encouraging clinical benefits, there are multiple challenges such as significant toxic effects and rapid development of drug resistance which limit the long-term benefits of VEGF-targeted therapy. Emerging evidence suggests that tumors can bypass VEGF/VEGFR inhibition by up-regulating other pro-angiogenic pathways to compensate for VEGF inhibition. For these reasons, additional strategies to inhibit tumor vasculature are being sought. In this regard, F16, a new compound developed by Rumbaugh-Goodwin Institute for Cancer Research, harbors the potential for suppressing VEGF-driven angiogenesis by selectively blocking the extracellular domain of VEGFR2, which plays a crucial role in endothelial cell proliferation, survival, and migration. F16 has shown a remarkable efficacy in inhibiting VEGFR-associated tyrosine kinase activities. On the other hand, Tie-2 receptor is predominantly expressed in the endothelium and has been shown to facilitate VEGF-mediated angiogenesis. Therefore, we hypothesize that dual targeting of VEGFR2 and Tie-2 using F16 and T2i respectively will result in augmented angiogenesis inhibition. To test our hypothesis, human umbilical vein endothelial cells (HUVECs) were used as a model for our initial validation studies. Our preliminary data indicated that combining F16 and T2i significantly inhibited HUVECs proliferation compared to monotherapies (P<0.001) and 90% inhibition of HUVECs proliferation was observed at 1μM of the drug combination. Moreover, the ability of the indicated drugs to inhibit angiogenesis was further evaluated using a Matrigel-based tube formation assay. Using the scoring system developed by our laboratory, combining F16 and T2i at 1μM scored five pluses, indicating that individual cells were well-separated as compared to monotherapies (three pluses and two pluses respectively). These findings clearly indicated that concurrent blockade of VEGFR2 and Tie-2 represented a new strategy to potentiate angiogenesis inhibition. However, further studies are required to test whether there would be imposing changes in the growth rates of human cancers implanted in a mouse model, and whether these changes are attributed to changes in tumor vasculatures. These studies will ultimately lead us to understand the pharmacodynamics of F16 and Tie-2 inhibitor for better clinical applications in the future. (This research was supported by Royal Dames of Cancer Research Inc., Ft. Lauderdale, Florida.) Citation Format: Khalid Alhazzani, Thanigaivelan Kanagasabai, Saad Alobid, Appu Rathinavelu. The impact of dual targeting VEGFR2 and Tie-2 on angiogenesis using in vitro model. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3257.

Ultrasound-enhanced bevacizumab release from echogenic liposomes for inhibition of atheroma progression

Context: Bevacizumab (BEV) is a monoclonal antibody to vascular endothelial growth factor (VEGF) that ameliorates atheroma progression by inhibiting neovascularization.Objective: We aimed to determine whether BEV release from echogenic liposomes (BEV-ELIP) could be enhanced by color Doppler ultrasound (US) and whether the released BEV inhibits VEGF expression by endothelial cells in vitro.Materials and methods: BEV-ELIP samples were subjected to 6 MHz color Doppler ultrasound (MI = 0.4) for 5 min. We assessed release of BEV with a direct ELISA and with fluoresceinated BEV (FITC-BEV) loaded into ELIP by the same method. Human umbilical vein endothelial cell (HUVEC) cultures were stimulated to express VEGF by 10 nM phorbol-12-myristate 13-acetate (PMA). Cell-associated VEGF levels were determined using a cell-based ELISA.Results: Overall, US caused an additional 100 µg of BEV to be released or exposed per BEV-ELIP aliquot within 60 min BEV-ELIP treated with US inhibited VEGF expression by 90% relative to non-treated controls and by 70% relative to BEV-ELIP without US. Also, US-treated BEV-ELIP inhibited HUVEC proliferation by 64% relative to untreated controls and by 45% relative to BEV-ELIP without US.Discussion and conclusion: We have demonstrated that BEV-ELIP retains its VEGF-binding activity in a liposomal formulation and that clinical Doppler US can significantly increase that activity, both by releasing free BEV and by enhancing the surface exposure of the immunoreactive antibody.

Zerumbone, Sesquiterpene Photochemical from Ginger, Inhibits Angiogenesis.

Here, we investigated the role of zerumbone, a natural cyclic sesquiterpene of Zingiber zerumbet Smith, on angiogenesis using human umbilical vein endothelial cells (HUVECs). Zerumbone inhibited HUVECs proliferation, migration and tubule formation, as well as angiogenic activity by rat aorta explants. In particular, zerumbone inhibited phosphorylation of vascular endothelial growth factor receptor-2 and fibroblast growth factor receptor-1, which are key regulators of endothelial cell function and angiogenesis. In vivo matrigel plug assay in mice demonstrated significant decrease in vascularization and hemoglobin content in the plugs from zerumbone-treated mice, compared with control mice. Overall, these results suggest that zerumbone inhibits various attributes of angiogenesis, which might contribute to its reported antitumor effects.

SiRNA Directed Against Annexin II Receptor Inhibits Angiogenesis via Suppressing MMP2 and MMP9 Expression

Background/Aims: Annexin II receptor (AXIIR) is able to mediate Annexin II signal and induce apoptosis, but its role in angiogenesis remains unclear. This study tries to investigate the role of AXIIR in angiogenesis and the plausible molecular mechanism. Methods/Results: RNA interference technology was used to silence AXIIR, and the subsequent effects in vitro and in vivo were evaluated thereafter. Our data indicated that human umbilical vein endothelial cells (HUVECs) expressed AXIIR and knockdown of AXIIR significantly inhibited HUVECs proliferation, adhesion, migration, and tube formation in vitro and suppressed angiogenesis in vivo. Furthermore, AXIIR siRNA induced cell arrest in the S/G2 phase while had no effect on cell apoptosis. We found that these subsequent effects might be via suppressing the expression of matrix metalloproteinase 2and matrix metalloproteinase 9. Conclusion: AXIIR participates in angiogenesis, and may be a potential therapeutic target for angiogenesis related diseases.

Total Alkaloids of Rubus alceifolius Poir Shows Anti-Angiogenic Activity In Vivo and In Vitro

Total alkaloids is an active ingredient of the natural plant Rubus alceifolius Poir, commonly used for the treatment of various cancers. Antitumor effects may be mediated through anti-angiogenic mechanisms. As such, the goal of the present study was to investigate and evaluate the effect of total alkaloids in Rubus alceifolius Poir (TARAP) on tumor angiogenesis and investigate the underlying molecular mechanisms of TARAP action in vivo and in vitro. A chick embryo chorioallantoic membrane (CAM) assay was used to assess angiogenesis in vivo. An MTT assay was performed to determine the viability of human umbilical vein endothelial cells (HUVECs) with and without treatment. Cell cycle progression of HUVECs was examined by FACS analysis with propidium iodide staining. HUVEC migration was determined using a scratch wound method. Tube formation of HUVECs was assessed with an ECMatrix gel system, and mRNA and protein expression of VEGF-A in both HUVECs and HepG2 human hepatocellular carcinoma cells were examined by RT-PCR and ELISA, respectively. Our results showed that TARAP inhibited angiogenesis in the CAM model in vivo and inhibited HUVEC proliferation via blocking cell cycle G1 to S progression in a dose- and time-dependent manners in vitro. Moreover, TARAP inhibited HUVEC migration and tube formation and downregulated mRNA and protein expression of VEGF-A in both HepG2 cells and HUVECs. Our findings suggest that the anti-angiogenic activity of TARAP may partly contribute to its antitumor properties and may be valuable for the treatment of diseases involving pathologic angiogenesis such as cancer.

Antiangiogenic effects of cucurbitacin-I.

Cucurbitacin-I is a naturally occurring tetracyclic triterpenoid compound with diverse physiological actions that include inducing apoptosis and blocking cell cycle progression of various cancer cells. However, its antiangiogenic activity has not yet been examined. Accordingly, we investigated the antiangiogenic efficacy and associated mechanisms of cucurbitacin-I in vitro using human umbilical vein endothelial cells (HUVECs). Cucurbitacin-I inhibited HUVEC proliferation, invasion, migration and tubule formation, as well as angiogenic activity by rat aorta explants. Notably, cucurbitacin-I inhibited phosphorylation of vascular endothelial growth factor receptor-2 and fibroblast growth factor receptor-1, which are key regulators of endothelial cell function and angiogenesis. In vivo matrigel plug assay in mice showed significant decrease in vascularization and hemoglobin content in the plugs from cucurbitacin-I-treated mice, compared with control mice. Overall, these results suggest that cucurbitacin-I inhibits various attributes of angiogenesis, which might contribute to its reported antitumor effects. Cucurbitacin-I warrants further investigation as an angiogenesis inhibitor for use in cancer treatment.

Citreoviridin inhibits cell proliferation and enhances apoptosis of human umbilical vein endothelial cells

In some areas of China, citreoviridin (CIT) is considered one of the risk factors for development of cardiovascular disease (CVD). Apoptosis of endothelial cell may induce vascular endothelium injury and atherosclerosis, which result in CVD probably. In this study, we investigated the effect of CIT on apoptosis and proliferation of human umbilical vein endothelial cells (HUVECs). The MTT assay was used to determinate HUVECs proliferation. Distribution of the cell cycle was analyzed by flow cytometry. The Annexin-V/PI staining was used to investigate cell apoptosis. Western blotting analysis was used to indicate changes in the expression level of apoptosis-related proteins. The results indicated that CIT inhibited HUVECs proliferation and the cells were arrested at G0/G1 phase, which is associated with decreased levels of cyclinD1 and increased expression of p53 and p21. The apoptosis rate of HUVECs was improved by CIT. The expression of Bcl-2 were down-regulated after CIT treatment, whereas the levels of Bax was significantly up-regulated. Furthermore, CIT-induced apoptosis was accompanied by the activation of caspase-3, -9. These findings demonstrate that CIT inhibits cell proliferation via DNA synthesis reduction and induces caspase-dependent apoptosis in HUVECs. CIT plays a pivotal role in the process of endothelial cell apoptosis, may thereby play an important role in the improvement of CVD in areas of China that have a high prevalence of CIT contamination.

SKLB-M8 Induces Apoptosis Through the AKT/mTOR Signaling Pathway in Melanoma Models and Inhibits Angiogenesis With Decrease of ERK1/2 Phosphorylation

SKLB-M8, a derivative of millepachine, showed significant anti-proliferative effects in melanoma cell lines. In this study, we investigated the anti-melanoma and anti-angiogenic activity of SKLB-M8 on three melanoma cell lines (A2058, CHL-1, and B16F10) and human umbilical vein endothelial cells (HUVECs). In vitro, SKLB-M8 showed anti-proliferative activity with IC50 values of 0.07, 0.25, and 0.88 μM in A2058, CHL-1, and B16F10 cell lines, respectively. Flow cytometory analysis showed that SKLB-M8 induced G2/M arrest in three melanoma cell lines, and western blotting demonstrated that SKLB-M8 down-regulated the expression of cdc2, up-regulated p53 in A2058 and CHL-1 cells, and triggered cell apoptosis through down-regulating AKT and phosphorylated mTOR (p-mTOR). SKLB-M8 also inhibited HUVEC proliferation, migration, invasion, and tube formation in vitro with the inhibition of phosphorylated ERK1/2 (p-ERK1/2). In vivo, alginate-encapsulated tumor cell assay revealed that SKLB-M8 suppressed B16F10 tumor angiogenesis. In CHL-1- and B16F10-tumor-bearing mouse models, SKLB-M8 inhibited tumor growth by oral treatment with less toxicity. CD31 immunofluoresence staining and caspase-3 immunohistochemistry indicated that SKLB-M8 inhibited melanoma tumor growth by targeting angiogenesis and inducing caspase3-dependent apoptosis. SKLB-M8 might be a potential anti-melanoma drug candidate.

Inhibition effects of gold nanoparticles on proliferation and migration in hepatic carcinoma-conditioned HUVECs

Tumor angiogenesis is a complicated process based upon a sequence of interactions between tumor and vessel endothelial cells. Tumor conditioned medium has been widely used to stimulate endothelial cells in vitro angiogenesis. This work was aimed to investigate the effects of gold nanoparticles (GNPs) on angiogenesis in hepatic carcinoma-conditioned endothelial cells. Human umbilical vein endothelial cells (HUVECs) were cultured with conditioned medium (CM) from the human hepatocarcinoma cell line HepG2 (HepG2-CM), and then treated with different concentrations of GNPs. The effects of GNPs on the viability, migration and active VEGF level of HUVECs were investigated by MTT assay, wound healing assay and transwell chamber assay, and ELISA assay, respectively. The data showed that GNPs significantly inhibited HUVECs proliferation and migration induced by HepG2-CM, and also reduced the levels of active VEGF in the co-culture system. Then, the alterations in morphology and ultrastructure of HUVECs detected by atomic force microscopy (AFM) showed that there appeared obvious pseudopodia, larger membrane particle sizes and much rougher surface in HUVECs after HepG2-CM treatment, which were all reversed after GNPs treatment. Changes in cytoskeleton of HUVECs determined by immunocytochemistry demonstrated that GNPs treatment remarkably inhibited the activation effect of HepG2-CM on HUVECs, which was associated with the disruption of actin filaments induced by GNPs. This study indicates that GNPs can significantly inhibit HepG2-CM activated endothelial cell proliferation and migration through down-regulation of VEGF activity and disruption of cell morphology, revealing the potential applications of GNPs as antiangiogenic agent for the treatment of hepatic carcinoma.

Anti-angiogenic effect of KH902 on retinal neovascularization

KH902 is a fusion protein derived from the extracellular domains of vascular endothelial growth factor (VEGF) receptors 1 and 2 and the Fc portion of immunoglobulin G1 (IgG1). Retinopathy of prematurity (ROP) is an eye disease that affects premature babies who have received intensive neonatal care, and the disorganization of retinal blood vessels may result in scarring and retinal detachment. This study was designed to examine the inhibitory effects of KH902 on mice with oxygen-induced retinopathy (OIR), one of the animal models of ROP. Human umbilical vein endothelial cells (HUVECs) were used for an in vitro study, and the C57BL/6 J OIR mouse model was used for an in vivo study. HUVECs were incubated with KH902 or a VEGF- and KH902-containing medium. Cell proliferation, migration, apoptosis, and tube formation were measured with BrdU incorporation, Transwell, flow cytometry, and Matrigel assays. C57BL/6 J mice were exposed to 75 % oxygen from postnatal day 7 (P7) to P12, after which the mice were brought to room air and intravitreously injected with KH902. At P18, the mice were perfused with fluorescein isothiocyanate (FITC)-dextran and Evans Blue, and flat-mounted retinas were used to measure the non-perfused and leakage areas. The data were analyzed with GraphPad Prism 5.0 software. In vitro, KH902 dose-dependently inhibited HUVEC proliferation in general culture medium and in VEGF165-containing medium at different time points. Moreover, KH902 inhibited HUVEC migration and tube formation and induced HUVEC apoptosis. In vivo, an intravitreous injection of KH902 reduced the retinal non-perfused area from 34 % in the control group to 19 % in the treatment group and significantly reduced the retinal leakage area from 18 % to 9 %. KH902 had marked inhibitory effects on angiogenesis both in vitro and in vivo. These data suggest that KH902 could serve as an innovative pharmaceutical agent to prevent retinal neovascularization (NV) and as a strategy for the treatment of ROP.

Inhibitory Effect of Paclitaxel and Rapamycin Individual and Dual Drug-Loaded Polymeric Micelles in the Angiogenic Cascade

Angiogenesis is an essential process for disease progression in many solid tumors. There are several major cascade events in the angiogenic process that can be targeted to inhibit new blood vessel formation in the tumor tissue. The purpose of this work is to evaluate the inhibitory effect of paclitaxel (PTX) and rapamycin (RAP) as individual and in dual drug-loaded poly(ethylene glycol)-block-poly(d,l-lactic acid) (PEG-b-PLA) micelles on the angiogenic cascade processes of proliferation, migration, and tube formation. PEG-b-PLA PTX and/or RAP micelles were formed and characterized for size and drug loading. Sizes of individual and dual drug micelles were below 40 nm. PEG-b-PLA micelles significantly enhanced the aqueous solubility of PTX 1.80 mg/mL and RAP 1.60 mg/mL. The PTX-RAP dual drug PEG-b-PLA micelles were able to load PTX and RAP at 1.60 mg/mL for both drugs. Cell proliferation, apoptosis, tubule formation, and migration studies were performed in human umbilical vein endothelial cells (HUVEC). PTX and RAP in DMSO inhibited HUVEC proliferation with IC50 values of 0.82 ± 0.02 and 13 829 ± 681 nM, respectively, while the combination of both drugs in DMSO produced synergistic inhibition. PTX and RAP individual micelles had IC50 values of 6.3 ± 1.1 and 14 051 ± 821 nM, respectively. PTX and dual drug micelles had a synergistic inhibition effect on HUVEC proliferation through the induction of apoptosis via caspase 3/7 activity. In vitro tube formation assay demonstrated significant inhibition of tube formation upon treatment with dual drug micelles as compared to individual PTX or RAP micelles. Migration studies in HUVEC have shown that individual PTX micelles inhibited cell migration at 1 nM, while RAP micelles did not show any inhibitory effect on cell migration. Interestingly, the presence of RAP in the dual drug micelles was able to initiate the inhibition of the migration of HUVEC at 0.1 nM concentration of PTX. These results indicate that PTX-RAP dual drug micelles have antiangiogenic effects in vitro mediated through three major events in the angiogenic process and have strong potential for further development as antiangiogenic chemotherapy.

Antiangiogenesis Effects of Endostatin in Retinal Neovascularization

Pathological retinal angiogenesis is a major cause of vision loss. Endostatin is a natural antiangiogenesis antitumor protein that is widely used in cancer studies. In this study, we investigated the efficacy and potential mechanisms of endostatin for the prevention of retinal neovascularization both in vitro and in vivo. Human umbilical vein endothelial cells (HUVECs) were used for the in vitro studies. HUVECs were incubated with endostatin or the vascular endothelial growth factor (VEGF) and endostatin for different time points. Cell proliferation, migration, cell cycling, and tube formation studies were carried out using a Cell Counting Kit-8 assay, a Transwell assay, flow cytometry, and a Matrigel assay, respectively. Enzyme-Linked Immunosorbent Assay (ELISA) was used to study VEGF and pigment epithelial-derived factor (PEDF) protein secretion from the HUVECs at different time points. A murine oxygen-induced retinopathy (OIR) model was used for the in vivo studies. Seven-day-old C57BL/6J pups (p7) were exposed to 75% oxygen for 5 days. On p12, the animals were returned to a normal atmosphere and were immediately injected intravitreously with 1.5 μL of a 5 mg/mL endostatin solution. At p18, the mice were perfused with fluorescein-dextran-FITC, and their retinas were flat mounted to measure the nonperfused area. Retinal VEGF and PEDF levels were also measured by ELISA Kits in the OIR mice at p18. In vitro, endostatin inhibited HUVEC proliferation in a dose-dependent manner and also inhibited HUVEC proliferation in a VEGF-containing medium. Additionally, endostatin can inhibit migration, tube formation, and VEGF secretion in HUVECs, while also inducing apoptosis in HUVECs at several time points. These effects were statistically significant when compared to the control group (P<0.05). In vivo, a single intravitreous injection of endostatin reduced the retinal nonperfused area from 30% in the control group to 23% in the treatment group (P<0.0001). Intravitrous injection of endostatin reduced VEGF levels in retinas, while it increased PEDF levels. Endostatin showed convincing inhibitory effects on angiogenesis both in vitro and in vivo. The inhibitory effects may be, at least partly, resulted from the restoration of the PEDF/VEGF ratio. These data suggest that endostatin could offer an innovative pharmaceutical strategy for the prevention of retinal neovascularization.

Effects of microRNA145 on proliferation and migration of human umbilical vein endothelial cells

Objective To investigate the effect of microRNA145 (miR145) on the proliferation and migration of human umbilical vein endothelial cells (HUVECs).Methods MiR145 mimic and negative control fragments were transfected into HUVECs via LipofectamineTM RNAiMAX.Gell counting kit-8 was used to study the proliferation of HUVECs.Transwell assay was used to measure the migration of HUVECs.The expression of miR145' s potential target gene a disintegrin and metalloproteinase 17(ADAM17) was detected by using real-time polymerase chain reaction (Real-time PCR) and Western blotting in HUVECs.Results 4-8 h after transfection,the A values in the group transfected with miR145mimic (0.34±0.01) were significantly lower than those in negative control group (0.44 ± 0.01,P ＜0.01).72 h after transfection,the A values in the group transfected with miR145 mimic (0.60 ± 0.09)were also significantly lower than in negative control group (0.86 ±0.05,P ＜0.01).The number of migratory cells in miR145 mimic-transfected group (135 ±6) was significantly less than in the negative control group (205 ± 30,P ＜ 0.05).The expression of ADAM17 mRNA and protein was downregulated in miR145 mimic-transfected group with the relative values being 0.34 ± 0.15 (P ＜ 0.01) and 0.65 ± 0.21(P ＜ 0.05),respectively.Conclusion MiR145 can effectively inhibit proliferation and migration of HUVECs probably by regulating the expression of ADAM17. Key words: microRNA145 ; Umbilical vein endothelial cells ; Proliferation; Migration ; Tumor angiogenesis

Piperine, a dietary phytochemical, inhibits angiogenesis

Angiogenesis plays an important role in tumor progression. Piperine, a major alkaloid constituent of black pepper, has diverse physiological actions including killing of cancer cells; however, the effect of piperine on angiogenesis is not known. Here we show that piperine inhibited the proliferation and G1/S transition of human umbilical vein endothelial cells (HUVECs) without causing cell death. Piperine also inhibited HUVEC migration and tubule formation in vitro, as well as collagen-induced angiogenic activity by rat aorta explants and breast cancer cell-induced angiogenesis in chick embryos. Although piperine binds to and activates the cation channel transient receptor potential vanilloid 1 (TRPV1), its effects on endothelial cells did not involve TRPV1 since the antiproliferative effect of piperine was not affected by TRPV1-selective antagonists, nor did HUVECs express detectable TRPV1 mRNA. Importantly, piperine inhibited phosphorylation of Ser 473 and Thr 308 residues of Akt (protein kinase B), which is a key regulator of endothelial cell function and angiogenesis. Consistent with Akt inhibition as the basis of piperine's action on HUVECs, inhibition of the phosphoinositide-3 kinase/Akt signaling pathway with LY-294002 also inhibited HUVEC proliferation and collagen-induced angiogenesis. Taken together, these data support the further investigation of piperine as an angiogenesis inhibitor for use in cancer treatment.

Polyethylene Glycol-Modified Pigment Epithelial-Derived Factor: New Prospects for Treatment of Retinal Neovascularization

Pathological retinal neovascularization and choroidal neovascularization are major causes of vision loss in a variety of clinical conditions, such as retinopathy of prematurity, age-related macular degeneration, and diabetic retinopathy. Pigment epithelial-derived factor (PEDF) has been found to be the most potent natural, endogenous inhibitor of neovascularization, but its application is restricted because of its instability and short half-life. Polyethylene glycol (PEG) has been used as a drug carrier to slow clearance rate for decades. The present study investigated PEGylated-PEDF for the first time and evaluated its long-term effects on preventing angiogenesis in vitro and in vivo. PEG showed lower cytotoxicity to human umbilical vein endothelial cells (HUVECs). In vitro, PEGylated-PEDF inhibited HUVEC proliferation, migration, tube formation, and vascular endothelium growth factor secretion and induced HUVEC apoptosis in a dose-dependent manner, and it showed a statistically significant difference compared with the PEDF treatment group. In vivo, PEGylated-PEDF had a long-lasting effect in both plasma and retinal concentrations. In an oxygen-induced retinopathy model, one intravitreous injection of PEGylated-PEDF after mouse pups were moved into room air resulted in a significant difference in the inhibition of retinal neovascularization, which decreased the nonperfusion area, compared with the PEDF-treated group. Our present study demonstrated for the first time the long-term inhibitory effects of PEGylated-PEDF on the prevention of neovascularization in vitro and in vivo. These data suggest that PEGylated-PEDF could offer an innovative therapeutic strategy for preventing retinal neovascularization.

Ras homolog gene family, member A promotes p53 degradation and vascular endothelial growth factor‐dependent angiogenesis through an interaction with murine double minute 2 under hypoxic conditions

Tumor neovascularization (TNV) is a common pathologic basis for malignant growth and metastasis. However, the mechanism of TNV pathogenesis is not fully understood. Ras homolog gene family, member A (RhoA), a Rho guanosine triphosphatase (GTPase) family member, may be involved in a hypoxia-induced vascular endothelial growth factor (VEGF) pathway that regulates TNV angiogenesis through an unclear mechanism. The regulation of RhoA on p53, the p53 binding protein homolog murine double minute 2 (MDM2), and VEGF was analyzed in hypoxic MCF-7 cells using Western blot analysis, real-time polymerase chain reaction (PCR) analysis, coimmunoprecipitation, and immunofluorescence staining assays. Changes in proliferation, invasion, migration, stress fiber formation, and tube formation were detected in an MCF-7 human umbilical vein endothelial cell (HUVEC) coculture system. Correlations of RhoA expression with MDM2, wild-type p53 (wt-p53), and VEGF expression in breast cancer tissues and relations between RhoA and breast cancer clinical features were analyzed by immunohistochemistry. Activated RhoA down-regulated p53 protein, which increased VEGF expression in hypoxic MCF-7 cells; whereas p53 messenger RNA levels were not altered. In addition, the ubiquitin-mediated degradation of p53 was enhanced by active RhoA. RhoA and MDM2 colocalized in the cytoplasm of hypoxic MCF-7 cells and interacted with each other physically. Furthermore, nutlin-3, a specific MDM2 inhibitor, was capable of reducing activated RhoA-induced p53 protein stability and attenuating VEGF accumulation. In an MCF-7-HUVEC coculture system, nutlin-3 effectively inhibited HUVEC proliferation, invasion, migration, stress fiber formation, and tube formation mediated by activated RhoA under hypoxic conditions. Data from 129 clinical breast cancer specimens with wt-p53 revealed that high RhoA expression was correlated with high MDM2 expression, low wt-p53 expression, and high VEGF expression. The current data suggested that activated RhoA promotes VEGF expression and hypoxia-induced angiogenesis through the up-regulation of MDM2 to decrease p53 stability.

Protein-bound polysaccharide from Phellinus linteus inhibits tumor growth, invasion, and angiogenesis and alters Wnt/β-catenin in SW480 human colon cancer cells

BackgroundPolysaccharides extracted from the Phellinus linteus (PL) mushroom are known to possess anti-tumor effects. However, the molecular mechanisms responsible for the anti-tumor properties of PL remain to be explored. Experiments were carried out to unravel the anticancer effects of PL.MethodsThe anti-cancer effects of PL were examined in SW480 colon cancer cells by evaluating cell proliferation, invasion and matrix metallo-proteinase (MMP) activity. The anti-angiogenic effects of PL were examined by assessing human umbilical vein endothelial cell (HUVEC) proliferation and capillary tube formation. The in vivo effect of PL was evaluated in an athymic nude mouse SW480 tumor engraft model.ResultsPL (125-1000 μg/mL) significantly inhibited cell proliferation and decreased β-catenin expression in SW480 cells. Expression of cyclin D1, one of the downstream-regulated genes of β-catenin, and T-cell factor/lymphocyte enhancer binding factor (TCF/LEF) transcription activity were also significantly reduced by PL treatment. PL inhibited in vitro invasion and motility as well as the activity of MMP-9. In addition, PL treatment inhibited HUVEC proliferation and capillary tube formation. Tumor growth of SW480 cells implanted into nude mice was significantly decreased as a consequence of PL treatment, and tumor tissues from treated animals showed an increase in the apoptotic index and a decrease in β-catenin expression. Moreover, the proliferation index and microvessel density were significantly decreased.ConclusionsThese data suggest that PL suppresses tumor growth, invasion, and angiogenesis through the inhibition of Wnt/β-catenin signaling in certain colon cancer cells.

SKLB1002, a Novel Potent Inhibitor of VEGF Receptor 2 Signaling, Inhibits Angiogenesis and Tumor Growth In Vivo

VEGF receptor 2 (VEGFR2) inhibitors, as efficient antiangiogenesis agents, have been applied in the cancer treatment. However, currently most of these anticancer drugs suffer some adverse effects. Discovery of novel VEGFR2 inhibitors as anticancer drug candidates is still needed. In this investigation, we adopted a restricted de novo design method to design VEGFR2 inhibitors. We selected the most potent compound SKLB1002 and analyzed its inhibitory effects on human umbilical vein endothelial cells (HUVEC) in vitro. Tumor xenografts in zebrafish and athymic mice were used to examine the in vivo activity of SKLB1002. The use of the restricted de novo design method indeed led to a new potent VEGFR2 inhibitor, SKLB1002, which could significantly inhibit HUVEC proliferation, migration, invasion, and tube formation. Western blot analysis was conducted, which indicated that SKLB1002 inhibited VEGF-induced phosphorylation of VEGFR2 kinase and the downstream protein kinases including extracellular signal-regulated kinase, focal adhesion kinase, and Src. In vivo zebrafish model experiments showed that SKLB1002 remarkably blocked the formation of intersegmental vessels in zebrafish embryos. It was further found to inhibit a new microvasculature in zebrafish embryos induced by inoculated tumor cells. Finally, compared with the solvent control, administration of 100 mg/kg/d SKLB1002 reached more than 60% inhibition against human tumor xenografts in athymic mice. The antiangiogenic effect was indicated by CD31 immunohistochemical staining and alginate-encapsulated tumor cell assay. Our findings suggest that SKLB1002 inhibits angiogenesis and may be a potential drug candidate in anticancer therapy.