Isoforms of soluble vascular endothelial growth factor in stress-related mental disorders: a cross-sectional study

Vascular endothelial growth factor (VEGF) has been implicated in the pathophysiology of stress-related mental disorders. However, VEGF levels have seldom been compared across mental disorders and never by isoforms. Pathophysiological processes involving leakage of astrocyte-derived extracellular vesicles (EVs) across the blood–brain barrier could be associated with VEGF levels in patients with stress-related mental disorders. This cross-sectional study compared plasma levels of VEGF121, VEGF165, and VEGF121 + VEGF165 (VEGFtotal) in patients with stress-induced exhaustion disorder (SED) (n = 31), patients with major depressive disorder (MDD) (n = 31), and healthy controls (n = 61). It also analyzed the correlation between VEGF and astrocyte-derived EVs in plasma. An enzyme-linked immunosorbent assay (ELISA) was used to measure VEGF121 and VEGF165 in citrate plasma, and flow cytometry was used to measure astrocyte-derived EVs in plasma. The mean concentration of soluble VEGF121 (sVEGF121) was significantly higher in patients with SED than healthy controls (P = 0.043). Mean sVEGF165 was significantly lower in patients with MDD than patients with SED (P = 0.004) or healthy controls (P = 0.037). Mean sVEGFtotal was significantly higher in patients with SED than in patients with MDD (P = 0.021) and also higher in patients with SED than healthy controls (P = 0.040). Levels of sVEGF121 were positively correlated with levels of astrocyte-derived EVs only in patients with SED (P = 0.0128). The same was true of levels of sVEGFtotal and astrocyte-derived EVs (P = 0.0046). Differing levels of VEGF isoforms may reflect different pathophysiological mechanisms in SED and MDD. Further research is needed to better understand the potential roles of VEGF isoforms and astrocyte-derived EVs in mental disorders.

Cancer-derived small extracellular vesicles promote angiogenesis by heparin-bound, bevacizumab-insensitive VEGF, independent of vesicle uptake

Cancer-derived small extracellular vesicles (sEVs) induce stromal cells to become permissive for tumor growth. However, it is unclear whether this induction solely occurs through transfer of vesicular cargo into recipient cells. Here we show that cancer-derived sEVs can stimulate endothelial cell migration and tube formation independently of uptake. These responses were mediated by the 189 amino acid isoform of vascular endothelial growth factor (VEGF) on the surface of sEVs. Unlike other common VEGF isoforms, VEGF189 preferentially localized to sEVs through its high affinity for heparin. Interaction of VEGF189 with the surface of sEVs profoundly increased ligand half-life and reduced its recognition by the therapeutic VEGF antibody bevacizumab. sEV-associated VEGF (sEV-VEGF) stimulated tumor xenograft growth but was not neutralized by bevacizumab. Furthermore, high levels of sEV-VEGF were associated with disease progression in bevacizumab-treated cancer patients, raising the possibility that resistance to bevacizumab might stem in part from elevated levels of sEV-VEGF.

Altered VEGF Splicing Isoform Balance in Tumor Endothelium Involves Activation of Splicing Factors Srpk1 and Srsf1 by the Wilms’ Tumor Suppressor Wt1

Angiogenesis is one hallmark of cancer. Vascular endothelial growth factor (VEGF) is a known inducer of angiogenesis. Many patients benefit from antiangiogenic therapies, which however have limitations. Although VEGF is overexpressed in most tumors, different VEGF isoforms with distinct angiogenic properties are produced through alternative splicing. In podocytes, the Wilms’ tumor suppressor 1 (WT1) suppresses the Serine/arginine-rich protein-specific splicing factor kinase (SRPK1), and indirectly Serine/arginine-rich splicing factor 1 (Srsf1) activity, and alters VEGF splicing. We analyzed VEGF isoforms, Wt1, Srpk1, and Srsf1 in normal and tumor endothelium. Wt1, Srpk1, Srsf1, and the angiogenic VEGF164a isoform were highly expressed in tumor endothelium compared to normal lung endothelium. Nuclear expression of Srsf1 was detectable in the endothelium of various tumor types, but not in healthy tissues. Inducible conditional vessel-specific knockout of Wt1 reduced Wt1, Srpk1, and Srsf1 expression in endothelial cells and induced a shift towards the antiangiogenic VEGF120 isoform. Wt1(−KTS) directly binds and activates both the promoters of Srpk1 and Srsf1 in endothelial cells. In conclusion, Wt1 activates Srpk1 and Srsf1 and induces expression of angiogenic VEGF isoforms in tumor endothelium.

Cell migration and growth induced by photo-immobilised vascular endothelial growth factor (VEGF) isoforms

VEGF isoforms immobilised by photo-reactive gelatin (AzPhe-gelatin) enhance cell migration and proliferation.

Single-nucleotide polymorphisms (SNPs) associated with outcomes in patients with localized and metastatic renal cell carcinoma (RCC).

437 Background: Despite major advances in the knowledge of the molecular basis of RCC, prognosis is still defined using clinical and pathological parameters. Moreover, no valid predictive biomarkers exist to help us selecting the best treatment for each patient. The aim of this work is analyzing the expression and determining the prognostic and predictive value of 64 key SNPs in 18 genes related with angiogenesis or metabolism of antiangiogenics in patients (pts) with both localized and advanced RCC treated at Hospital Universitario Virgen del Rocío. Methods: DNA from formalin fixed paraffin embedded tumor and non-tumor samples from 99 pts with RCC (26 advanced/ 73 localized) was extracted with QiAGEN Kit and amplified with a specific primers pool for every SNP as determined by the manufacturer (Lifetech). 64 SNPs were chosen based on their Minor Allele Frequency by HapMap, linkage disequilibrium by Haploview, and information from SNP data base (dSNP) and were studied by TaqMan OpenArray (Lifetech). The presence of the selected SNPs was correlated with clinical features, disease free survival (DFS), overall survival (OS), and response to treatment (RR). SPSS v16 was utilized for statistical analyses. Results: In pts with localized RCC, 6 SNPs in 3 genes involved in angiogenesis predicted for worse DFS (VEGFR2: rs10013228, rs2071559; PDGFRA: rs2228230) and shorter OS (VEGFR2: rs10013228; VEGFR3: rs6877011, rs307826) (p<0.05). In the advanced setting, 7 SNPs in genes related to both angiogenesis and metabolism of antiangiogenics determined inferior OS (IL8: rs2227543, NR1l2: rs3814055, NR1l3: rs2307424, PDGFA: rs9800958, PDGFRB: rs2302273) and worse RR (VEGFA: rs699947, rs3025010 p<0.01)). Additionally 3 SNPs in PDGFR-B and VEGF isoforms predicted for better RR (PDGFRB: rs17708574 (p=0.08), VEGFB: rs594942 (p=0.03), VEGFC: rs2016110 (p=0.07). Conclusions: Genetic analysis of RCC patients might provide valuable prognostic/predictive information. A set of SNPs in genes critical to angiogenesis and metabolism of antiangiogenics seem to determine post-surgical outcomes and treatment response in our series. These results are promising. Validation of the results is ongoing.