Inhibitory Effects Of Bevacizumab Research Articles

Von Willebrand factor and cancer: Another piece of the puzzle

Von Willebrand factor and cancer: Another piece of the puzzle

The inhibitory effect of D2 dopaminergic agonists on VEGF and VEGF‐R genes expression and blood vessels formation

AbstractPurposeVEGF and its receptor VEGF‐R play an important role in high vascular permeability and new blood vessels formation in various retinal diseases as wet Age‐related Macular Degeneration (wAMD), Diabetic Macular Oedema (DMO) or Proliferative Diabetic Retinopathy (PDR). The aim of this study was to evaluate the influence of selected D2 dopaminergic agonists: bromocriptine, cabergoline and pergolide on VEGF‐A and VEGF receptor‐2 (VEGFR‐2) genes expression and blood vessels formation in Danio rerio (Zebrafish) larvae.MethodsVEGF‐A and VEGFR‐2 genes expression was measured in real‐time polymerase chain reaction (rt‐PCR) 5 days post fertilization (dpf) after blood vessels formation stimulated by cobalt chloride (CoCl2). The inhibitory effect of bromocriptine, cabergoline, pergolide on VEGF‐A and VEGFR‐2 genes expression were compared with the inhibitory effect of bevacizumab (VEGF inhibitor). The inhibitory effect of bromocriptine, cabergoline, pergolide and bevacizumab on angiogenesis of Sub‐Intestinal Vessels Plexus (SIVP), Retinal Vessels (RV) and Tail Vessels (TV) was assessed in 72, 96 and 120 hours post fertilization (hpf).ResultsBromocriptine, cabergoline, pergolide and bevacizumab decreased VEGF‐A and VEGFR‐2 genes expression 5 dpf. Bromocriptine, cabergoline, pergolide and bevacizumab inhibited stimulated angiogenesis of SIVP, RV and TV.ConclusionsD2 dopaminergic agonists inhibit VEGF and VEGFR‐2 genes expression and stimulated angiogenesis in larvae of Danio rerio. This effect is comparable with bevacizumab – clinically used VEGF inhibitor. D2 dopaminergic agonists can be a potential group of drugs with anty‐VEGF effect.

Inhibitory effects of bevacizumab on filtering bleb scarring following trabeculectomy in rabbits

Background The primary reason to trabeculectomy failure is fibrosis of conjunctiva and episclera because of progressive fibroblast proliferation and collagen deposition of the filtration bleb.Conventional methods of inhibiting bleb scarring was intraoperative application of mitomycin C (MMC), but many complications occured after surgery.Researches showed that bevacizumab was an antifibrotic agent, and whether it can suppress scarring of filtering bleb after trabeculectomy is concerned. Objective The aim of this study was to evaluate the antifibrotic efficacy of bevacizumab after trabeculectomy in rabbits. Methods Forty New Zealand rabbits were randomly divided into four groups.Trabeculectomy was performed on the right eyes of each rabbits.The rabbits received subconjunctival injection of 0.05 ml bevacizumab (25 mg/ml) at the end of operation in the bevacizumab single injection group.The same dose of bevacizumab was respectively injected at the end of operation as well as 3 days and 7 days after operation in the bevacizumab repitition injection group, and 0.05 ml normal saline solution was used in the same way in the normal saline group.In the MMC group, MMC cotton patch with 0.2 mg/ml was placed under the Tenon caplsule and scleral flap for 3 minutes during operation.The intraocular pressure (IOP), bleb area and shape were evaluated during the 28-day period.The animals were sacrificed on postoperative day 14 and 28, respectively for the histopathologic examination of bleb.The expression of CD31 in the bleb was detected by immunohistochemistry for the calculation of microvessels.All experiments were performed in accordance with the ethics code for animal experimentation and approved by the Institutional Review Board of Tianjin Eye Hospital. Results No significant difference was found in the postoperative IOP among the groups (F=0.88, P=0.47). Compared with the bevacizumab single injection group, MMC group and normal saline group, the shape of bleb was higher and much diffuse with sparse vessels 7 days after operation in the bevacizumab repitition injection group.The survival time of bleb was 27 days, 19 days and 13 days in the bevacizumab repitition injection group, the bevacizumab single injection group, MMC group and normal saline group, respectively.The percentage of collagen deposition area was (49.18±1.54)%, (26.41±1.23)%, (50.68±1.87)% and (70.63±1.81)% at day 14 postoperative in the bevacizumab single injection group, bevacizumab repitition injection group, MMC group and normal saline group, respectively, with the largest area in the normal saline group, and percentage of collagen deposition area was significantly reduced in the bevacizumab repitition injection group compared with the bevacizumab single injection group (all at P<0.05). The percentage of collagen deposition area was (66.82±1.53)% at day 28 postoperative in the bevacizumab repitition injection group, while complete scarring was seen in other 3 groups.The number of microvessels was least at postoperative day 14 in the bevacizumab repitition injection group compared with the bevacizumab single injection group, MMC group and normal saline group (all at P<0.05). The number of microvessels was more in postoperative day 28 in the bevacizumab repitition injection group (3.51±0.31) compared with other groups (all at P<0.05). Conclusions Subconjunctival injection of bevacizumab following trabeculectomy can improve the successful rate of surgery by remaining the survival time of filtering bleb, inhibiting the bleb scarring in rabbits. Key words: Antibodies, monoclonal, humanized; Bevacizumab; Conjunctiva/pathology; Disease models, animal; Fibrosis/prevention c Glaucoma/surgery; Trabeculectomy; Wound healing/drug effects

Bevacizumab activity in gastric cancer cells with high expression of VEGF.

64 Background: Metastasis of cancer cells is associated with numerous activating molecules, including vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), and tumor necrosis factor (TNF)-α. Excess VEGF production induces hematogenous metastasis in gastric cancer (GC) cells. To understand the anti-metastatic effect of bevacizumab, an anti-VEGF monoclonal antibody developed for selective inhibition of tumor angiogenesis, we investigated VEGF-induced expression of key adhesion molecules in human umbilical vein endothelial cells (HUVECs) and the inhibitory effect of bevacizumab on the adhesion of GC cells expressing high levels of VEGF. Methods: We measured the soluble VEGF (sVEGF) produced by 7 GC cells by ELISA. We evaluated intercellular adhesion molecule (ICAM)-1, vascular cell adhesion molecule (VCAM)-1, and E-selectin expression in HUVECs pretreated with SNU-1-conditioned medium (SNU-1 CM) or recombinant VEGF (rhVEGF) at different time points by western blotting. Results: We identified that SNU-1 cells secreted the highest sVEGF concentration in 7 GC cells. After rhVEGF pretreatment, ICAM-1 and E-selectin expression were highest at 4–6 h and 2 h, respectively, but VCAM-1 expression was unchanged. Bevacizumab cotreatment markedly decreased VCAM-1 and E-selectin expression to basal levels, whereas ICAM-1 expression was unaffected. The SNU-1 adherent cell percentage decreased following bevacizumab cotreatment of SNU-1 CM- or rhVEGF-pretreated HUVECs. Investigation of SNU-1-cell invasiveness through activated HUVECs revealed less than 10 invasive adherent cells, whereas no cells were found after bevacizumab cotreatment. Conclusions: Our preclinical data suggests that bevacizumab, might contribute to anti-metastasis by inhibiting SNU-1 cell adhesion to HUVECs by reducing E-selectin and VCAM-1 expression.

Experimental study on the inhibitory effect of bevacizumab on choroidal neovascularization in rat

Objective To observe the inhibitory effects and characteristics of intravitreal injection with bevacizumab on laser-induced choroidal neovascularization (CNV).Methods Twelve male brown norway (BN) rats were divided into the bevacizumab group and control group with six rats in each group.One eye of rats were received a series of 8 diode laser esions around optic disc to induce CNV,then the rats in bevacizumab group and control group underwent intravitreal injection with 2 μl bevacizumab and ringer's lactate.On days 7,14,and 21,the morphology and leakage of CNV were observed by fundus fluorescein angiography (FFA) and indocyanine green angiography (ICGA).On day 21 after photocoagulation,thephotocoagulated eyes were enucleated and processed for histopathologie examination,including hematoxylin and eosin (H&E) staining and immunohistochemistry staining for vascular endothelial growth factor (VEGF).Results On day 7 after photocoagulation,ICGA showed that CNV developed in the bevacizumab group and the control group.FFA showed that leakage intensity in the bevacizumab group was significantly lower than that in the control group,but the bevacizumab group gradually increased over time.The mean thickness of CNV significantly decreased in the bevacizumab group.The CNV in the bevacizumab group were negative for VEGF according to the result of immmuohistochemistry staining.Conclusions Early intravitreal injection with 2 μl bevacizumab can reduce the thickness of CNV and inhibit the leakage of CNV.However,bevacizumab could neither block the formation of CNV,nor suppress the permeability permanently.Combined other therapies with bevacizumab may be more potential to treat CNV effectively. Key words: Choroidal neovascularization/drug therapy; Angiogenesis inhibitors/therapeutic use; Antibodies,monoclonal/therapeutic use; Antibodies,monoclonal/administration & dosage; Disease models,animal

Inhibitory effects of bevacizumab on angiogenesis and corneal neovascularization

To evaluate the inhibitory effects of bevacizumab (Avastin) on angiogenesis using cultured human umbilical vein endothelial cells (HUVECs) in vitro and on corneal neovascularization by subconjunctival injection of bevacizumab in vivo. After the HUVECs were exposed to different concentrations of bevacizumab stimulated with VEGF (10 ng/ml) for 2, 6, and 24 hours, cellular-activity-like proliferation, migration and tube formation were assessed. Subconjunctival injection of bevacizumab (2.5 mg/0.1 ml) was performed after corneal chemical burn injury. Then the cornea was evaluated by biomicroscopy, fluorescein angiography, and light microscopy. The inhibitory effects of bevacizumab on VEGF-induced HUVECs proliferation showed a dose-dependent response for 2 and 6 hours, but all groups were effectively inhibited regardless of the concentration of bevacizumab for 24 hours. The inhibitory effects of bevacizumab on the migration of VEGF-induced HUVECs showed a time- and dose-dependent response. The inhibitory effects of bevacizumab on VEGF-induced HUVECs tube formation showed a dose-dependent response only for 24 hours. On days 3 and 8 after the subconjunctival injection, bevacizumab-treated eyes showed less neovascular growth than BSS-treated eyes in biomicroscopic, fluorescein angiographic, and light microscopic findings in vivo. Bevacizumab effectively inhibits angiogenesis and corneal neovascularization, and could be used as a inhibitor of corneal neovascularization in the future.

Inhibitory Effect of Bevacizumab on the Angiogenesis and Growth of Retinoblastoma

To evaluate the potential effect of bevacizumab, a monoclonal antibody against vascular endothelial growth factor (VEGF), on the angiogenesis and tumor growth of retinoblastoma in vitro and in vivo. The antiangiogenic effects of bevacizumab were evaluated in a coculture of a Y-79 human retinoblastoma cell line and a human umbilical vein endothelial cell line by means of a cell proliferation assay kit and a VEGF enzyme-linked immunosorbent assay. The Y-79 xenotransplanted nude mice were treated with bevacizumab intraperitoneally twice weekly for 4 weeks, during which each tumor was measured once a week. The mice were then euthanized, and the weight of each tumor and its microvessel density were determined via CD34 immunohistochemical staining. The mean (standard error of the mean) increased human umbilical vein endothelial cell proliferation, when cocultured with Y-79 (156% [1%]), was suppressed 58% (5%) by the blockage of VEGF induced by bevacizumab. By causing a 2-fold reduction in microvessel density in the Y-79 xenograft model, bevacizumab induced a 75% reduction in the growth of the retinoblastomas without producing significant systemic toxicity. Conclusions and Clinical Relevance Treatment with bevacizumab suppressed the angiogenesis and growth of retinoblastoma in vitro and in vivo. Bevacizumab is likely to be of benefit in the treatment of retinoblastoma.

Bevacizumab as a Potent Inhibitor of Inflammatory Corneal Angiogenesis and Lymphangiogenesis

To analyze whether bevacizumab can inhibit inflammatory angiogenesis and lymphangiogenesis in the cornea. Bevacizumab (Avastin; Roche, Welwyn Garden City, UK) is a recombinant, humanized, monoclonal antibody against VEGF-A that has been approved by the U.S. Food and Drug Administration for the treatment of colon carcinomas. The mouse model of suture-induced corneal neovascularization was used to assess the antihemangiogenic and antilymphangiogenic effect of bevacizumab by systemic and topical application. Corneal flatmounts were stained with LYVE-1 as a specific lymphatic vascular endothelial marker and CD31 as a pan-endothelial marker, and blood and lymph vascularized areas were analyzed morphometrically. The inhibitory effect of bevacizumab on lymphatic endothelial cells (LECs) was analyzed with a colorimetric (BrdU) proliferation ELISA. The binding ability of bevacizumab to murine VEGF-A was analyzed by Western blot, ELISA, and surface plasmon resonance. The systemic and topical applications of bevacizumab significantly inhibited the outgrowth of blood (P < 0.006 and P < 0.0001, respectively) and lymphatic (P < 0.002 and P < 0.0001, respectively) vessels. Inhibition of the proliferation of LECs was also significant (P < 0.0001). Western blot analysis, ELISA, and the surface plasmon resonance assay showed that bevacizumab binds murine VEGF-A. Topical or systemic application of bevacizumab inhibits both inflammation-induced angiogenesis and lymphangiogenesis in the cornea. This finding suggests an important role of VEGF-A in corneal lymphangiogenesis. Bevacizumab may be useful in preventing immune rejections after penetrating keratoplasty or tumor metastasis via lymphatic vessels.