Inhibition of Angiogenesis by Recombinant VEGF Receptor Fragments

Applications of Biomolecular Nanostructures for Anti-Angiogenic Theranostics

Angiogenesis is a physiological process of forming new blood vessels that has pathological importance in seemingly unrelated illnesses like cancer, diabetes, and various inflammatory diseases. Treatment targeting angiogenesis has shown promise for these types of diseases, but current anti-angiogenic agents have critical limitations in delivery and side-effects. This necessitates exploration of alternative approaches like biomolecule-based drugs. Proteins, lipids, and oligonucleotides have recently become popular in biomedicine, specifically as biocompatible components of therapeutic drugs. Their excellent bioavailability and potential bioactive and immunogenic properties make them prime candidates for drug discovery or drug delivery systems. Lipid-based liposomes have become standard vehicles for targeted nanoparticle (NP) delivery, while protein and nucleotide NPs show promise for environment-sensitive delivery as smart NPs. Their therapeutic applications have initially been hampered by short circulation times and difficulty of fabrication but recent developments in nanofabrication and NP engineering have found ways to circumvent these disadvantages, vastly improving the practicality of biomolecular NPs. In this review, we are going to briefly discuss how biomolecule-based NPs have improved anti-angiogenesis-based therapy.

Expression of VGRNb-PE immunotoxin in transplastomic lettuce (Lactuca sativa L.)

KEY MESSAGE

This research has shown, for the first time, that plant chloroplasts are a suitable compartment for synthesizing recombinant immunotoxins and the transgenic immunotoxin efficiently causes the inhibition of VEGFR2 overexpression, cell growth and proliferation. Angiogenesis refers to the formation of new blood vessels, which resulted in the growth, invasion and metastasis of cancer. The vascular endothelial growth factor receptor 2 (VEGFR2) plays a major role in angiogenesis and blocking of its signaling inhibits neovascularization and tumor metastasis. Immunotoxins are promising therapeutics for targeted cancer therapy. They consist of an antibody linked to a protein toxin and are designed to specifically kill the tumor cells. In our previous study, VGRNb-PE immunotoxin protein containing anti-VEGFR2 nanobody fused to the truncated form of Pseudomonas exotoxin A has been established. Here, we expressed this immunotoxin in lettuce chloroplasts. Chloroplast genetic engineering offers several advantages, including high levels of transgene expression, multigene engineering in a single transformation event and maternal inheritance of the transgenes. Site specific integration of transgene into chloroplast genomes, and homoplasmy were confirmed. Immunotoxin levels reached up to 1.1% of total soluble protein or 33.7 µg per 100 mg of leaf tissue (fresh weight). We demonstrated that transgenic immunotoxin efficiently causes the inhibition of VEGFR2 overexpression, cell growth and proliferation. These results indicate that plant chloroplasts are a suitable compartment for synthesizing recombinant immunotoxins.

Overweight and obesity versus concentrations of VEGF-A, sVEGFR-1, and sVEGFR-2 in plasma of patients with lower limb chronic ischemia

OBJECTIVE

Being overweight or obese comprises a significant risk factor for atherosclerosis. Fat tissue also generates factors stimulating angiogenesis, the process by which new blood vessels form. The purpose of this paper is to assess concentrations of the vascular endothelial growth factor A (VEGF-A) and its soluble type-1 and type-2 receptors (sVEGFR-1 and sVEGFR-2) in plasma of patients with peripheral arterial disease (PAD) depending on the level of nutrition according to body mass index (BMI).

METHODS

The study group included patients suffering from symptomatic PAD (n=46) in Fontaine classes IIa-IV without any history of neoplastic disease and who have a normal BMI (n=15), are overweight (n=21) or are obese (n=10). The control group (n=30) consisted of healthy non-smoking volunteers who were neither overweight nor obese. Venous blood plasma samples were collected from both groups at rest in the morning to determine plasma concentrations of VEGF-A, sVEGFR-1, and sVEGFR-2 using the enzyme-linked immunosorbent assay (ELISA) method.

RESULTS

The group of patients with PAD co-existent with being overweight or obese tended to have higher mean concentration levels of VEGF-A and sVEGFR-2 when compared with patients suffering from PAD with normal BMI. A statistically significant positive correlation was obtained between BMI and average plasma concentrations of sVEGFR-2 (R=0.37, P=0.0103). However, no significant correlation was noticed between BMI and VEGF-A or sVEGFR-1 concentrations.

CONCLUSIONS

A positive correlation determined between the level of antiangiogenic factor and BMI value may be indicative of the linearly growing prevalence of some antiangiogenic factors in patients with metabolic disorders, which may be one of numerous factors contributing to incomplete efficiency of collateral circulation development in patients with PAD.

Association between kinase insert domain-containing receptor gene polymorphisms and silent brain infarction: a Korean study

BACKGROUND

Kinase insert domain-containing receptor (KDR), vascular endothelial growth factor receptor-2, play a pivotal role in endothelial dysfunction, which may lead to silent brain infarction (SBI). We evaluated whether single nucleotide polymorphisms (SNPs) of KDR genes are associated with increased risk of SBI in a Korean population.

METHODS

A total of 383 patients with SBI and 387 controls were genotyped for the KDR -604T>C, 1192G>A, and 1719A>T SNPs. We separately analyzed this association according to the age (age≥65 and age<65) and the gender. We also compared haplotype frequencies between SBI patients and controls.

RESULTS

Genotype frequencies for three SNPs did not differ significantly between SBI patients and controls. In addition, haplotype analysis for three SNPs did not show a difference between patients and controls. However, the frequency of genotype of KDR -604T>C was significantly associated with an increased risk of SBI in the age<65 years old group (AOR=1.515, 95% CI, 1.003 to 2.289, p=0.048) and in male group (AOR=1.596, 95% CI, 1.018 to 2.503, p=0.042).

CONCLUSIONS

KDR -604T>C SNP may serve as genetic markers for the increased risk of SBI among the younger (<65 years) or male only Korean subpopulations.