The antiangiogenic activity of a soluble fragment of the VEGFR extracellular domain

Histoprotective Effect of Essential Oil from Citrus aurantifolia in Testosterone-Induced Benign Prostatic Hyperplasia Rat

BACKGROUND

Benign prostatic hyperplasia (BPH) is a common urological disorder reported among ageing men.

OBJECTIVE

The study assessed histoprotective effect of lime essential oil (LEO) in a rat model of testosterone-induced benign prostatic hyperplasia (BPH) and evaluated its ability to reverse testosterone-mediated changes in the testis, kidney, and liver.

MATERIALS AND METHODS

Adult Sprague Dawley (aged 12 weeks, 240-390 g) male rats were intramuscularly injected with testosterone enanthate (TE) (10 mg/kg) reconstituted in olive oil for ten days to establish benign prostatic hyperplasia (serum PSA level ≥ 1.24 ng/ml) in. After confirmation of BPH (sustained serum PSA level ≥ 1.24 ng/ml), rats in all groups (LEO: 30, 100, and 300 mg/kg, po, n = 6; finasteride: 15 mg/kg, po, n = 6) except model (BPH without treatment) and sham (no BPH and no treatment) groups were treated for 21 days. At the end of treatment, rats were anesthetised and blood was collected via cardiac puncture to determine serum PSA and total antioxidant capacity (TAC) levels. The prostate gland, testis, kidney, and liver were harvested, weighed, histologically processed and stained with H&E.

RESULTS

LEO- and finasteride-treated groups recorded lesser mean prostatic weights relative to their model group. Baseline mean serum PSA level of LEO- and finasteride-treated groups reduced significantly (p < 0.05) relative to model group. Serum TAC levels were also higher in LEO- and finasteride-treated groups relative to model group. LEO-treated groups had less thickened glandular epithelium, smaller acini, fewer prostatic secretions and more fibromuscular stroma relative to model group. LEO and finasteride treatment produced improved histomorphological characteristics of testis, kidney, and liver compared to model group.

CONCLUSION

By the current results, Citrus aurantifolia LEO may possess active agents that can be explored for translational medicine against BPH.

Overview of the detection methods for equilibrium dissociation constant KD of drug-receptor interaction

Drug-receptor interaction plays an important role in a series of biological effects, such as cell proliferation, immune response, tumor metastasis, and drug delivery. Therefore, the research on drug-receptor interaction is growing rapidly. The equilibrium dissociation constant (KD) is the basic parameter to evaluate the binding property of the drug-receptor. Thus, a variety of analytical methods have been established to determine the KD values, including radioligand binding assay, surface plasmon resonance method, fluorescence energy resonance transfer method, affinity chromatography, and isothermal titration calorimetry. With the invention and innovation of new technology and analysis method, there is a deep exploration and comprehension about drug-receptor interaction. This review discusses the different methods of determining the KD values, and analyzes the applicability and the characteristic of each analytical method. Conclusively, the aim is to provide the guidance for researchers to utilize the most appropriate analytical tool to determine the KD values.

Angiogenic growth factors interactome and drug discovery: The contribution of surface plasmon resonance

Angiogenesis is implicated in several pathological conditions, including cancer, and in regenerative processes, including the formation of collateral blood vessels after stroke. Physiological angiogenesis is the outcome of a fine balance between the action of angiogenic growth factors (AGFs) and anti-angiogenic molecules, while pathological angiogenesis occurs when this balance is pushed toward AGFs. AGFs interact with multiple endothelial cell (EC) surface receptors inducing cell proliferation, migration and proteases upregulation. On the contrary, free or extracellular matrix-associated molecules inhibit angiogenesis by sequestering AGFs (thus hampering EC stimulation) or by interacting with specific EC receptors inducing apoptosis or decreasing responsiveness to AGFs. Thus, angiogenesis results from an intricate network of interactions among pro- and anti-angiogenic molecules, EC receptors and various modulators. All these interactions represent targets for the development of pro- or anti-angiogenic therapies. These aims call for suitable technologies to study the countless interactions occurring during neovascularization. Surface plasmon resonance (SPR) is a label-free optical technique to study biomolecular interactions in real time. It has become the golden standard technology for interaction analysis in biomedical research, including angiogenesis. From a survey of the literature it emerges that SPR has already contributed substantially to the better understanding of the neovascularization process, laying the basis for the decoding of the angiogenesis "interactome" and the identification of "hub molecules" that may represent preferential targets for an efficacious modulation of angiogenesis. Here, the still unexploited full potential of SPR is enlightened, pointing to improvements in its use for a deeper understanding of the mechanisms of neovascularization and the identification of novel anti-angiogenic drugs.

Generation and characterization of a novel human IgG1 antibody against vascular endothelial growth factor receptor 2

VEGF and its receptors, especially VEGFR2 (KDR), are known to play a critical role in angiogenesis under both physiological and pathological conditions, including cancer and angiogenic retinopathies. This study was aimed at developing a fully human IgG1 antibody (mAb-04) constructed from a phage-derived scFv, targeting the VEGF/VEGFR2 pathway. Firstly, an innovative transfection system, containing two recombinant expression vectors (pMH3 and pCApuro), were introduced into CHO-s cells and clones with higher yield selected accordingly. After an optimal fermentation condition was determined, fed-batch fermentation was performed in 5-L bioreactor with a final yield up to 60 mg/L. Further, cell proliferation, wound healing, transwell invasion, tube formation and chick embryo chorioallantoic membrane assays showed significant anti-angiogenic activity of mAb-04 in vitro and in vivo. In addition, the results of Western blotting indicated the ability of mAb-04 to inhibit VEGF-induced VEGFR2 signaling pathway. Finally, ADCC assay demonstrated that mAb-04 is capable of mediating tumor cell killing in presence of effector cells. This study has therefore proved that the full-length antibody targeting human VEGFR2 has potential clinical applications in the treatment of cancer and other diseases where pathological angiogenesis is involved.

Expression and characterization of a soluble VEGF receptor 2 protein

Objective

To clone and express a truncated, soluble vascular endothelial growth factor receptor 2 (sVEGFR2) possessing the combined-functional domains 1–3 and 5 in eukaryotic cells and to test the inhibitory effects of full length VEGFR2 in vivo.

Results

pCMV6-trunctated-rVegfr2 (6100 bp) was successfully cloned. The transfection experiments showed that either pCMV6-truncated-rat-Vegfr2 (pCMV6-truncated-rVegfr2) or pCMV6-rVegfr2 inhibited the expression of intracellular green fluorescent protein, which is usually used as an exogenous transfected reporter gene to determine the transfected efficiency. An analysis of the transfected cells revealed that the amount of full-length VEGFR2 protein in the pCMV6-truncated-rVegfr2 transfected cells was 20% lower than that in the negative control (non-transfected HEK 293 cells). The differences in test results between the transfected and negative control groups were greatest from 24–30 h after transfection; this period was therefore chosen as optimal for collecting culture supernatants. This analysis was highly sensitive for detecting the amount of sVEGFR2 protein expressed and secreted by the cells, and the sVEGFR2 protein content was found to increase by approximately 26% in the transfected cells compared to that in the negative control cells (68.2% ± 1.7% vs. 41.9% ± 2.9%, P = 0.000) and by 18% compared to the negative control cells (68.2% ± 1.7% vs. 50.0% ± 0.5%, P = 0.003). Propidium iodide and Hoechst staining indicated no significant change in the number of HEK293 cells undergoing apoptosis 6 days after pCMV6-trucated-Vegfr2 transfection, compared to the negative control. Soluble VEGFR2 produced by pCMV6-truncated-rVegfr2 inhibited full-length VEGFR2 protein expression in the cell membrane.

Conclusions

This study employed a eukaryotic system to express sVEGFR2. The use of transient transfection technology greatly improved transfect efficiency. Recombinant sVEGFR2 inhibited the effect of endogenous full-length VEGFR2 but was not cytotoxic.