VEGF Receptor Research Articles

A real-world study of treatment patterns among patients (pts) with metastatic colorectal cancer (mCRC) receiving third-line (3L) or fourth-line (4L) treatment in the US.

64 Background: There are limited real-world data describing 3L and 4L treatments for pts with mCRC. However, the landscape is evolving with new options becoming available, including fruquintinib, a highly selective oral inhibitor of all 3 VEGF receptors, approved by the US FDA in November 2023. This study aimed to understand pt characteristics and real-world treatment patterns in 3L and 4L to characterize the standard of care, adherence to guidelines, and identify unmet needs among pts with mCRC in the US, prior to recent changes in the landscape. Methods: A retrospective study of adults with mCRC who had received ≥3L of therapy between 1/1/2018 and 3/31/2023 in the US-based Flatiron electronic health records database. In two cohorts, defined by initiating 3L and 4L systemic treatment, pt demographics, clinical characteristics, and treatment by line of therapy were summarized. Results: Overall, 5401 pts were included in the 3L cohort and 2868 pts in the 4L cohort: median age at baseline was 63 and 62 years (yrs), 56% and 56% were male, 43% and 43% had a KRAS variant, and 46% and 49% had liver metastasis, respectively. 96% of pts in the 3L cohort received standard chemotherapy (CT) +/- targeted therapy as 1L treatment (55% CT + anti-vascular endothelial growth factor [VEGF] therapy; 34% CT only; 7% CT + anti-epidermal growth factor receptor [EGFR] therapy). In 2L, 87% of pts had standard CT-containing regimens (53% CT + anti-VEGF therapy; 19% CT alone; 15% CT + anti-EGFR therapy). A similar treatment history was observed for the 4L cohort. Commonly used 3L regimens in the 3L cohort were trifluridine/tipiracil (TAS-102; 11%), regorafenib (rego; 10%), and standard CT-containing regimens (54%; including: 12% FOLFIRI + bevacizumab [bev], 7% FOLFOX + bev, 4% FOLFIRI, 3% FOLFOX, and 15% standard CT + anti-EGFR therapy). Approximately 47% (n=2513) of pts did not receive subsequent treatments after 3L. In the 4L cohort, use of TAS-102 (16%) and rego (15%) increased slightly in 4L, accompanied with a moderate decrease in CT-containing regimens (42%; including 6% FOLFOX + bev, 5% FOLFIRI + bev, 3% FOLFOX, 3% FOLFIRI, and 12% standard CT + anti-EGFR therapy). Approximately 4% of pts in the 3L and 4L cohorts received TAS-102 + bev in 3L and 4L, respectively. Pts receiving standard CT-containing regimens were slightly younger (<65 yrs: 3L 57%, 4L 58%) and had better Eastern Cooperative Oncology Group performance status (ECOG PS; 0-1: 3L 77%, 4L 77%) vs pts receiving TAS-102 (<65 yrs: 3L 54%, 4L 58%; ECOG PS 0-1: 3L 70%, 4L 68%) or rego (<65 yrs: 3L 50%, 4L 53%; ECOG PS 0-1: 3L 68%, 4L 70%). Conclusions: Characterization of treatment patterns in US pts from 1/2018 to 3/2023 showed that standard CT +/- targeted therapy was used frequently in 3L and 4L, demonstrating an unmet need for additional therapies. Approval of novel treatments, such as fruquintinib, may help to address this need.

Based on network pharmacology and molecular docking, the mechanism of action of Chinese herbal compound on mycoplasma synovial sac of chicken was studied

Mycoplasma synoviae (MS) is a wall-less pathogen primarily transmitted through the respiratory tract, causing synovitis and airsacculitis in poultry, which leads to substantial economic losses in the poultry industry. China has a long-standing tradition of Chinese medicine with abundant medicinal resources, renowned for its safety, efficacy, and holistic regulatory effects. This study aims to screen a traditional Chinese medicine (TCM) compound with anti-inflammatory and immunoregulatory properties and preliminarily validate its in vitro efficacy against MS infections. Based on the research foundation of this experiment and findings from previous studies, this study utilized network pharmacology analysis and molecular docking techniques to identify the anti-inflammatory and immunoregulatory effects of traditional Chinese medicinal herbs, including Rhizoma Coptidis, Honeysuckle (Flos Lonicerae Japonicae), Radix Codonopsis, and Radix Glycyrrhizae.The primary active components and potential targets were identified using the Traditional Chinese Medicine Systems Pharmacology Database (TCMSP) and other platforms. Protein-protein interaction (PPI) networks, Gene Ontology (GO) functional annotation, and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were employed to identify critical therapeutic targets. The AutoDock software was used for molecular docking between active components and core targets. Subsequently, in vitro experiments were conducted to validate the effects of key active components on MS targets. The analysis revealed that this TCM compound contains 122 active components, including flavonoids (e.g., quercetin, trimethylisoflavone), chromones (e.g., anti-inflammatory coumarin A), and triterpenes (e.g., glycyrrhizic acid B). These components act on 739 pharmacological targets, and Venn analysis identified 23 intersection targets related to MS. Further analysis indicated that STAT3, IL6, and IL1B were potential core targets. KEGG pathway enrichment analysis showed that MAPK, FoxO, and Toll-like receptor signaling pathways played critical roles in the pathology and treatment of MS, while GO analysis emphasized the significance of the NF-κB signaling pathway and VEGF receptor pathway in immune regulation, inflammation, and tissue repair. Molecular docking results demonstrated that lignans and quercetin in this TCM compound exhibited strong binding affinities to IL1B, IL6, and STAT3, potentially modulating these key targets to exert anti-inflammatory and immunoregulatory effects. In vitro experiments further validated the significant inhibitory effects of quercetin and glycyrrhizic acid on MS infection. The findings suggest that this TCM compound may exert therapeutic effects on MS infection by regulating targets such as CASP3, TLR4, STAT3, IL6, and IL1B, and modulating signaling pathways including MAPK, NF-κB, and FoxO.

Divergent sex-specific pannexin-1 mechanisms in microglia and Tcells underlie neuropathic pain.

Chronic pain is a leading cause of disability, affecting more women than men. Different immune cells contribute to this sexual divergence, but the mechanisms, especially in females, are not well defined. We show that pannexin-1 (Panx1) channels on microglia and Tcells differentially cause mechanical allodynia, a debilitating symptom of neuropathic pain. In male rodents, Panx1 drives vascular endothelial growth factor-A (VEGF-A) release from microglia. Cell-specific knockdown of microglial Panx1 or pharmacological blockade of the VEGF receptor attenuated allodynia in nerve-injured males. In females, nerve injury increased spinal CD8+ Tcells and leptin levels. Leptin release from female-derived CD8+ Tcells was Panx1 dependent, and intrathecal leptin-neutralizing antibody injection sex-specifically reversed allodynia. Adoptive transfer of female-derived CD8+ Tcells caused robust allodynia, which was prevented by a leptin-neutralizing antibody or leptin small interfering RNA (siRNA) knockdown. Panx1-targeted approaches may alleviate neuropathic pain in both sexes, while Tcell- and leptin-directed treatments could have sex-dependent benefits for women.

From bench to bedside: elucidating VEGF(R) inhibitor-related heart failure in cancer treatment

BackgroundVascular endothelial growth factor (VEGF) and VEGF receptor (VEGFR) inhibitors play a pivotal role in treating various tumors; however, the clinical characteristics and molecular mechanisms of their associated heart failure (HF) remain incompletely understood.MethodsWe investigated the epidemiological characteristics of VEGF or VEGFR inhibitors [VEGF(R)i]-related heart failure (VirHF) using the global pharmacovigilance database Vigibase. The phenotypic features and molecular mechanisms of VirHF were characterized using VEGF(R)i-treated mouse models through a combination of echocardiography, histopathological analysis, and transcriptome sequencing. Furthermore, we performed a retrospective analysis of cardiac function parameters in patients undergoing VEGF(R)i treatment at local hospitals.ResultsIn the analysis of 1871 VirHF cases, elderly patients (≥ 65 years) and female subjects demonstrated an elevated risk of occurrence. Experimental studies in mice revealed that both acute and chronic VEGF(R)i administration resulted in reduced left ventricular EF, cardiomyocyte hypertrophy, and myocardial fibrosis. Transcriptomic analysis identified significant dysregulation of multiple key signaling pathways, including DNA repair (R = 0.46), mitochondrial ATP synthesis (R = 0.39), glycogen metabolism regulation (R = 0.45), and proteasome-mediated protein degradation (R = 0.45). Moreover, significant upregulation was observed in inflammatory pathways, specifically those involving IL-1, IL-6, TNF-α, and IRF3/IRF7-mediated immune responses. Clinical cohort analyses demonstrated significant elevations in both cardiac injury biomarkers (NT-proBNP, CK-MB, cTnT) and inflammatory mediators (CRP) following VEGF(R)i administration.ConclusionsOur findings present the first comprehensive characterization of VirHF clinical features and elucidate its underlying molecular mechanisms, thereby providing a theoretical framework for optimizing the clinical safety of VEGF(R)i therapy.

Nature’s arsenal unleashed: Senegalia modesta derived thymol halts cancer progression by suppressing proangiogenic genes

Inhibiting angiogenesis with plant-derived bioactive compounds can inhibit tumour progression. Antiangiogenic potential of Senegalia modesta was analysed by preparing and analysing ethanolic extracts of S.modesta by GC-MS and HPLC to identify bioactive components. In-vivo blood vessel formation assays in mice and chorioallantoic membrane assays (CAM) in eggs were employed to assess the antiangiogenic effects. qPCR was performed to elucidate mRNA expression of proangiogenic genes in MDA-MB-231 cells after exposure to S.modesta and thymol. Molecular docking analysis highlighted the interaction of thymol with VEGF receptors. S.modesta treatment significantly delayed wound healing in mice compared to control group. GC-MS and HPLC analyses thymol as a bioactive compound in S.modesta extract. CAM assay indicated reduced angiogenesis in thymol-treated groups, further confirmed by downregulation of proangiogenic genes. Molecular docking of thymol with VEGFR1/VEGFR2 revealed strong binding affinity, suggesting thymol-mediated receptor blocking. Thymol exhibits antiangiogenic potential and may serve as a promising therapeutic agent against cancer.

Angiogenic effects of Type 2 diabetes on the dental pulp.

To investigate the influence of type 2 diabetes (T2D) and hyperglycaemia on blood vessels and angiogenic markers in the dental pulp. Extracted non-carious permanent molar teeth were collected from patients with well-controlled T2D (n = 10) and non-T2D (controls) (n = 10). The pulp was examined qualitatively using haematoxylin and eosin and Van Gieson stains. Immunohistochemistry (IHC) identified the primary receptor for VEGF, VEGFR2, and the endothelial cell marker CD34. Primary human dental pulp cell (hDPC) lines (n = 3) were established from tissue explants and cells were grown in media containing 5.5 mM D-glucose (control), 12.5 mM (prediabetes) and 25 mM (T2D) D-glucose under normoxic conditions for 24, 48 and 72 h. Assays for metabolic activity (PrestoBlue) and cell viability (Crystal Violet staining) assessed the hDPC response to hyperglycaemia. The expression of angiogenic genes VEGFA, KDR, FLT-1, ANGPT1, ANGPT2, TIE1 and TEK were analysed using quantitative real-time polymerase chain reaction. ELISAs were used to quantify the level of expressed protein for VEGFA, ANG1, ANG2, TIE1, and TIE2 in the media. Data analyses were performed using GraphPad Prism and anova tests at p < .05. Blood vessels in T2D samples had thicker walls and stained strongly for elastin and collagen compared with non-T2D samples. VEGFR2 protein was not seen in any T2D samples but consistently detected in healthy specimens. Culturing healthy cells in high glucose (25 mM) significantly reduced cell viability at 24 h compared to the control (p = .005) and 12.5 mM glucose (p = .001) but the metabolic activity was not greatly affected by glucose and time. VEGFA mRNA and VEGFA protein expression were detected in the hDPCs in the presence of hyperglycaemia over time; however, the primary receptor, VEGFR2/KDR, was not detected. Genes for the ANG1 and ANG2 and their receptors were expressed at all glucose concentrations but hyperglycaemia upregulated ANG2 mRNA. Proteins for all growth factors were detected in the media however proteins for TIE1 and TIE2 receptors were not. T2D and hyperglycaemia may impair the angiogenic response in the pulp similar to other body site. The scarcity of VEGFR2 and increased expression of ANG2 in response to hyperglycaemia suggests that VEGF and ANG-Tie1/Tie2 signalling may be compromised.

In Silico-Designed G-Quadruplex Targeting Peptide Attenuates VEGF-A Expression, Preventing Angiogenesis in Cancer Cells.

Vascular endothelial growth factor-A (VEGF-A) is a growth factor and pluripotent cytokine that promotes angiogenesis in cancer cells, transitioning to an angiogenic phenotype. The binding of VEGF-A protein to VEGF receptors (VEGFR-1 and VEGFR-2) initiates a cascade of events that stimulates angiogenesis by facilitating the migration and enhancing the permeability of endothelial cells. The proximal promoter of the VEGF gene encompasses a 36-base pair region (from -85 to -50) that can form a stable G-quadruplex (G4) structure in specific conditions. The activity of the VEGF promoter is reliant on this structure. During cancer progression, the VEGF-A G4 succumbs to cellular pressure and fails to maintain a stable structure. This shifts the balance to form a duplex structure, increasing the transcription rate. Earlier research has tried to develop small-molecule ligands to target and stabilise G4, demonstrating the possibility of suppressing VEGF expression. However, they either lack specificity or toxic. Peptides, on the other hand, are significantly less studied as G4 binders. Here, we designed a peptide that successfully binds and stabilises the VEGF-A G4 while reducing its gene expression. This further alters the expression fate of the VEGF-A signalling cascade and blocks angiogenesis in cancer cells. We employed high-resolution nuclear magnetic resonance (NMR) spectroscopy and molecular dynamics simulation to elucidate the chemical details of G4-peptide interaction. In addition, we used qPCR and western blot techniques to investigate the expression pattern of the molecules implicated in the VEGF-A signalling cascade. The study explores the intricate relationship between peptides and quadruplex structures, revealing valuable insights that can improve the design of pharmacophores targeting the dynamic quadruplex structure. The results of our study are encouraging, opening possibilities for advancements in, the characterisation and optimisation of peptides as G-quadruplex ligands in view of their potential therapeutic uses.

Development of axitinib-loaded polymeric ocular implants for the treatment of posterior ocular diseases.

Diabetic retinopathy (DR) and age-related macular degeneration (AMD) are the primary causes of vision impairment and blindness worldwide. The current treatment for these diseases is an intravitreal injection of anti-VEGF agents, which are costly and require frequent injections. Implants can be used to sustain the release of drugs and minimize side effects. Axitinib (AX) is a potent VEGF receptor inhibitor and a promising candidate for treating posterior ocular diseases, such as diabetic retinopathy (DR) and age-related macular degeneration (AMD). A sustained release of AX was successfully achieved from 3D-printed AX-loaded implants fabricated using the well-known 3D printing technique, semi-solid extrusion (SSE). AX at concentrations of 10% w/w and 20% w/w was incorporated within the polycaprolactone (PCL) and Precirol®-based matrix. The fabricated implants were characterized via FTIR spectroscopy, SEM imaging, and thermal analysis. The implants were also evaluated for their drug release and biocompatibility. The AX-loaded implants exhibited thermal stability, and no chemical interactions were found between AX and the matrix components. The release mechanism study of AX revealed that the concentration of drug loading influenced AX release from the implant, with a 10% w/w and 20 %w/w of AX showing first-order and Korsmeyer-Peppas mechanism, respectively. A biocompatibility study using ARPE-19 cells confirmed that AX-loaded implants are nontoxic and safe for ocular use.

Sexually dimorphic differences in angiogenesis markers are associated with brain aging trajectories in humans.

Aberrant angiogenesis could contribute to the development of cognitive impairment and represent a therapeutic target for preventing dementia. However, most studies addressing angiogenesis and cognitive impairment focus on model organisms. To test the relevance of angiogenesis to human cognitive aging, we evaluated associations of circulating blood markers of angiogenesis with brain aging trajectories in a pooled two-center sample from deeply phenotyped longitudinal human cohorts (n = 435; female = 207, age = 74 ± 9) using cognitive assessments, biospecimens, structural brain imaging, and clinical data. Blood markers included ligands involved in angiogenesis and vascular function such as basic fibroblast growth factor (bFGF), members of the vascular endothelial growth factor family (VEGFA, VEGFB, and VEGFC), and placental growth factor (PlGF), in addition to their receptors VEGF receptor 1 (VEGFR1) and tyrosine kinase with immunoglobulin and EGF homology domain 2 (Tie2). Machine learning and traditional statistics revealed sexually dimorphic associations of plasma angiogenic growth factors with brain aging outcomes, including executive function and gray matter atrophy. Specifically, markers of angiogenesis were associated with higher executive function and less brain atrophy in younger women (not men), a directionality of association that reversed around age 75. Higher concentrations of bFGF, known for pleiotropic effects on multiple cell types, predicted favorable cognitive trajectories in both women and men. An independent sample from a multicenter dataset (MarkVCID; n = 80; female = 30, age = 73 ± 9) was used to externally validate these findings. In conclusion, this analysis demonstrates the association of angiogenesis to human brain aging, with potential therapeutic implications for vascular cognitive impairment and dementia.

Platelet-rich plasma promotes wound repair in diabetic foot ulcer mice via the VEGFA/VEGFR2/ERK pathway

Diabetic foot ulcers (DFUs) are a severe microvascular complication. Platelet-rich plasma (PRP) pitches in DFU treatment. This study explored the mechanism of PRP facilitating wound repair in DFU mice via vascular endothelial growth factor A (VEGFA)/VEGF receptor 2 (VEGFR2)/extracellular signal-regulated kinase (ERK) pathway. The DFU mouse model was established, with wound skin injected with PRP, followed by the detections of wound area, histopathological changes, and CD31-positive cells. IL-6/TNF-α/VEGFA/VEGFR2/p-VEGFR2/(ERK1/2)/(p-ERK1/2) levels in wound tissue homogenates were assessed. VEGFA-VEGFR2 interaction was evaluated. PRP-treated DFU mice were simultaneously treated with fruquintinib/PD98059. PRP reduced wound area, IL-6 and TNF-α levels, elevated epidermal dermal thickness, CD31-positive cell number, and aligned tissue structure, which were mitigated by fruquintinib/PD98059. PRP promoted VEGFR2 phosphorylation. PRP and fruquintinib/PD98059 abated p-VEGFR2/VEGFR2 or p-ERK1/2/ERK1/2 levels in DFU mice. PRP activated the ERK pathway through VEGFA/VEGFR2. Collectively, PRP promoted VEGFR2 phosphorylation and activated the ERK pathway, thereby facilitating wound repair in DFU mice.

Auxiliary effect of trolox on coenzyme Q10 restricts angiogenesis and proliferation of retinoblastoma cells via the ERK/Akt pathway

Reactive oxygen species (ROS) are essential for cancer signalling pathways and tumour maintenance, making ROS targeting a promising anti-cancer strategy. Coenzyme Q10 (CoQ10) has been shown to be effective against various cancers, but its impact on retinoblastoma, alone or with trolox, remains unreported. Cytotoxicity of CoQ10 alone and with trolox was evaluated in normal human retinal pigment epithelium cells (ARPE-19) and Y79 retinoblastoma cells using CCK-8. Flow cytometry was used to assess apoptosis, cell cycle, ROS, and mitochondrial membrane potential (MMP). Anti-angiogenic potential was tested using human umbilical vein endothelial cells (HUVECs) and chick chorioallantoic membrane (CAM) assays. Mechanistic studies were conducted via RT-PCR and western blotting. CoQ10, alone and with trolox, reduced Y79 cell viability, induced apoptosis through excess ROS generation, and decreased MMP significantly. Both treatments caused G2/M phase cell arrest. The CAM assay showed a significant reduction in endothelial cell proliferation, evidenced by fewer number of co-cultured HUVECs when exposed to CoQ10 or CoQ10 with trolox. The combination of CoQ10 and trolox significantly reduced VEGF-A, ERK, and Akt receptor levels, while CoQ10 alone significantly inhibited ERK and Akt phosphorylation. Together, CoQ10 and trolox reduced protein expression of VEGFA. CoQ10 alone and with trolox, induces apoptosis in Y79 retinoblastoma cells by inhibiting the ERK/Akt pathway and downregulating VEGFA. This study is the first to report the in vitro and in-ovo anti-cancer potential of CoQ10 alone or when combined with trolox, on human retinoblastoma Y79 cells.

Repeated treatment with VEGF receptor inhibitors induces phenotypic changes in endothelial cells and pericytes in the rat retina

Abnormal ocular angiogenesis is a major cause of visual impairment and vision loss in neovascularization-related diseases. Currently, anti-vascular endothelial growth factor (VEGF) drugs are used to treat ocular neovascularization, but repeated injections are needed to maintain their therapeutic effects. However, repeated injection of anti-VEGF drugs may affect the retinal blood vessel phenotype and diminish therapeutic effects. In this study, we aimed to investigate the phenotypic changes in endothelial cells and pericytes caused by the repeated interruption of the VEGF receptor signaling pathway in neonatal rats. KRN633 (10 mg/kg), a VEGF receptor tyrosine kinase inhibitor, was subcutaneously administered on postnatal day (P)-7 and P8 (first round), P14 and P15 (second round), and P21 and P22 (third round). The rat eyes were collected on P7, P9, P14, P16, P21, P23, P28, and P35. Using retinal flat-mount specimens stained with specific markers for vascular endothelial cells, basement membranes, and pericytes, the arteriolar tortuosity, capillary area density, and distribution of pericytes were evaluated. Significant loss of capillaries was observed the day after the first round of KRN633 treatment, after which aggressive angiogenesis occurred, leading to the formation of tortuous arterioles. Rats that completed second and third rounds of KRN633 treatment showed more severe abnormalities in the retinal vasculature than those that only completed first round treatment. Repeated treatment with KRN633 decreased the anti-angiogenic effects but increased the immunoreactivity of α-smooth muscle actin in the pericytes on veins and capillaries. α-Smooth muscle actin expression was inversely correlated to anti-angiogenic effects. Overall, these results revealed that repeated interruption of VEGF receptor signaling pathway altered the phenotypes of endothelial cells and pericytes and induced anti-VEGF drug resistance. Therefore, careful follow-up is necessary when using anti-VEGF drugs to treat abnormal angiogenesis-associated ocular diseases.

Comprehensive analysis of VEGF/VEGFR inhibitor-induced immune-mediated hypertension: integrating pharmacovigilance, clinical data, and preclinical models.

This study aimed to elucidate the differential immunological mechanisms and characteristics of hypertension induced by VEGF inhibitors (VEGFi) and VEGF receptor inhibitors (VEGFRi), with the goal of optimizing monitoring strategies and treatment protocols. We investigated the risk of immune-related adverse events associated with VEGFi/VEGFRi-induced hypertension by analyzing the FDA Adverse Event Reporting System (FAERS) database. Findings were corroborated with blood pressure characteristics observed in clinical patients and preclinical models exposed to various VEGF/VEGFRi. Clinical and preclinical studies were conducted to compare immunological responses and hypertension profiles between inhibitor classes. An integrative analysis across cancer types and species was performed, focusing on key signaling pathways. Analysis of FAERS data, in conjunction with clinical observations, revealed that both VEGFi and VEGFRi significantly elevated the risk of immune-mediated, blood pressure-related adverse events (ROR=7.75, 95% CI: 7.76-7.95). Subsequent clinical and preclinical studies demonstrated differential immunological responses and hypertension profiles between inhibitor classes. VEGFRi exhibited a more rapid onset, greater blood pressure elevation, and higher incidence of immune-mediated adverse events compared to VEGFi (Systolic BP: ROR=0 for VEGFi vs. ROR=12.25, 95% CI: 6.54-22.96 for VEGFRi; Diastolic BP: ROR=5.09, 95% CI: 0.60-43.61 for VEGFi vs. ROR=12.90, 95% CI: 3.73-44.55 for VEGFRi). Integrative analysis across cancer types and species, focusing on key signaling pathways, revealed that VEGF/VEGFRi-induced blood pressure elevation was associated with immunomodulation of the mitogen activated protein kinase (MAPK) pathway (R=-0.379, P=0.0435), alterations in triglyceride metabolism (R=-0.664, P=0.0001), modulation of myo-inositol 1,4,5-trisphosphate-sensitive calcium release channel activity (R=0.389, P=0.0378), and dysregulation of nitric oxide eNOS activation and metabolism (R=-0.439, P=0.0179). The temporal dynamics of these effects demonstrated greater significance than dose-dependent responses. Both VEGFi and VEGFRi significantly augmented the risk of immune-mediated, blood pressure-related adverse events, with VEGFRi inducing a more rapid and pronounced onset of blood pressure elevation and a higher incidence of immune-related, blood pressure-associated adverse events compared to VEGFi.

New insights in the mechanisms of opioid analgesia and tolerance: Ultramicronized palmitoylethanolamide down-modulates vascular endothelial growth factor-A in the nervous system

Growing evidence suggests that opioid analgesics modulate angiogenesis during pathophysiological processes. Vascular endothelial growth factor-A (VEGF-A) was recently proposed to be involved in pain development. To date, no anti-angiogenic drug is used for pain management. When administered in a bioavailable formulation, (i.e., ultramicronized) N-palmitoylethanolamine (PEA) delays the onset of morphine tolerance, improves morphine analgesic activity and reduces angiogenesis in in vivo models. This study aimed at investigating whether VEGF-A is involved in PEA-induced delay of morphine tolerance. The anti-VEGF-A monoclonal antibody bevacizumab was used as a reference drug. Preemptive and concomitant treatment with ultramicronized PEA delayed morphine tolerance and potentiated the analgesic effect of morphine, while counteracting morphine-induced increase of VEGF-A in the nervous system. Similar results were obtained when bevacizumab was administered together with morphine. Of note, bevacizumab showed an analgesic effect per se. In equianalgesic treatment regimens (obtained through increasing morphine doses and associating PEA), PEA resulted in lower expression of VEGF-A in dorsal root ganglia (DRG) and spinal cord compared to morphine alone. Similar results were observed for plasma levels of the soluble VEGF receptor 1 (sFLT-1). Moreover, in morphine-treated animals, two pain-related genes (i.e., Serpina3n and Eaat2) showed a more than 3-fold increase in their expression at spinal cord and DRG level, with the increase being significantly counteracted by PEA treatment. This study supports the hypothesis that the effects of PEA on morphine analgesia and tolerance may be mediated by the down-modulation of VEGF-A and sFLT-1 in the nervous system and plasma, respectively.

Synthetic Antiangiogenic Vascular Endothelial Growth Factor-A Splice Variant Revascularizes Ischemic Muscle in Peripheral Artery Disease.

Alternative splicing in the eighth exon C-terminus of VEGF-A (vascular endothelial growth factor-A) results in the formation of proangiogenic VEGF165a and antiangiogenic VEGF165b isoforms. The only known difference between these 2 isoform families is a 6-amino acid switch from CDKPRR (in VEGF165a) to SLTRKD (in VEGF165b). We have recently shown that VEGF165b can induce VEGFR2-activation but fails to induce VEGFR1 (VEGF receptor 1)-activation. The molecular mechanisms that regulate VEGF165b's ability toward differential VEGFR2 versus VEGFR1 activation/inhibition are not yet clear. Hypoxia serum starvation was used as an invitro peripheral artery disease model. Unilateral single ligation of the femoral artery was used as a preclinical peripheral artery disease model. VEGFR1 activating ligands have 2 arginine (RR) residues in their eighth exon C-terminus, that were replaced by lysine-aspartic acid (KD) in VEGF165b. A synthetic anti-angiogenic VEGF165b splice variant in which the KD residues were switched to RR (VEGF165bKD→RR) activated both VEGFR1- and VEGFR2-signaling pathways to induce ischemic-endothelial cell angiogenic capacity invitro and enhance perfusion recovery in a severe experimental-peripheral artery disease model significantly higher than VEGF165a. Phosphoproteome arrays showed that the therapeutic efficacy of VEGF165bKD→RR over VEGF165a is due to its ability to induce P38-activation in ischemic endothelial cells. Our data shows that the KD residues regulate VEGF165b's VEGFR1 inhibitory property but not VEGFR2. Switching these KD residues to RR resulted in the formation of a synthetic/recombinant VEGF165bKD→RR isoform that has the ability to activate both VEGFR1- and VEGFR2-signaling and induce ischemic-endothelial cell angiogenic and proliferative capacity that matched the angiogenic requirement necessary to achieve perfusion recovery in a severe experimental-peripheral artery disease model.

VEGF-dependent testicular vascularisation involves MEK1/2 signalling and the essential angiogenesis factors, SOX7 and SOX17

BackgroundAbnormalities of in utero testis development are strongly associated with reproductive health conditions, including male infertility and testis cancer. In mouse testes, SOX9 and FGF9 support Sertoli cell development, while VEGF signalling is essential for the establishment of vasculature. The mitogen-activated protein kinase (MAPK) pathway is a major signalling cascade, essential for cell proliferation, differentiation and activation of Sry during primary sex-determination, but little is known about its function during fetal testis morphogenesis. We explored potential functions of MAPK signalling immediately after the establishment of testis cords in embryonic day (E)12.5 Oct4-eGFP transgenic mouse testes cultured using a MEK1/2 inhibitor.ResultsRNA sequencing in isolated gonadal somatic cells identified 116 and 114 differentially expressed genes after 24 and 72 h of MEK1/2 inhibition, respectively. Ingenuity Pathway Analysis revealed an association of MEK1/2 signalling with biological functions such as angiogenesis, vasculogenesis and cell migration. This included a failure to upregulate the master transcriptional regulators of vascular development, Sox7 and Sox17, VEGF receptor genes, the cell adhesion factor gene Cd31 and a range of other endothelial cell markers such as Cdh5 (encoding VE-cadherin) and gap junction genes Gja4 and Gja5. In contrast, only a small number of Sertoli cell enriched genes were affected. Immunofluorescent analyses of control testes revealed that the MEK1/2 downstream target, ERK1/2 was phosphorylated in endothelial cells and Sertoli cells. Inhibition of MEK1/2 eliminated pERK1/2 in fetal testes, and CD31, VE-cadherin, SOX7 and SOX17 and endothelial cells were lost. Consistent with a role for VEGF in driving endothelial cell development in the testis, inhibition of VEGFR also abrogated pERK1/2 and SOX7 and SOX17 expressing endothelial cells. Moreover, while Sertoli cell proliferation and localisation to the testis cord basement membrane was disrupted by inhibition of MEK1/2, it was unaffected by VEGFR inhibition. Instead, inhibition of FGF signalling compromised Sertoli cell proliferation and localisation to the testis cord basement membrane.ConclusionsTogether, our data highlight an essential role for VEGF-dependent MEK1/2 signalling in promoting vasculature and indicate that FGF signalling through MEK1/2 regulates Sertoli cell organisation in the developing mouse testis.

Unveiling the antitumor synergy between pazopanib and metformin on lung cancer through suppressing p-Akt/ NF-κB/ STAT3/ PD-L1 signal pathway

Pazopanib, an inhibitor of the VEGF receptor tyrosine kinase, has demonstrated significant antitumor effects in lung cancer. However, its application as a standard treatment for this type of cancer is limited by its drug resistance and toxicity. Metformin has the potential to combat lung cancer by modifying the tumor’s immune microenvironment.In this study, we investigated the potential antitumor effects and the associated underlying molecular mechanisms of the combination of pazopanib and metformin in lung cancer. In vitro studies were conducted using the A549 and H460 lung cancer cell lines, whereas urethane-induced lung cancer-bearing mice were used for in vivo assessments. The urethane-induced mice received oral administration of pazopanib (50 mg/kg) and/or metformin (250 mg/kg) for a duration of 21 days.The results indicated that the MTT assay demonstrated a combined cytotoxic effect of the pazopanib/metformin combination in H460 and A549 cells, as evidenced by CI and DRI analyses. The observed increase in annexin V levels and the corresponding increase in Caspase-3 activity strongly suggest that this combination induced apoptosis.Furthermore, the pazopanib/metformin combination significantly inhibited the p-Akt/NF-κB/IL-6/STAT3, HIF1α/VEGF, and TLR2/TGF-β/PD-L1 pathways while also increasing CD8 expression in vivo. Immunohistochemical analysis revealed that these antitumor mechanisms were manifested by the suppression of the proliferation marker Ki67. In conclusion, these findings revealed that metformin augments the antitumor efficacy of pazopanib in lung cancer by simultaneously targeting proliferative, angiogenic, and immunogenic signaling pathways, metformin enhances the antitumor effectiveness of pazopanib in lung cancer, making it a promising therapeutic option for lung cancer.

Fucoxanthin Attenuates Angiogenesis by Blocking the VEGFR2-Mediated Signaling Pathway through Binding the Vascular Endothelial Growth Factor.

Fucoxanthin, a dietary carotenoid, is predominantly found in edible brown algae and is commonly consumed worldwide. Fucoxanthin has been shown to possess beneficial health activities such as antidiabetic, anti-inflammatory, antimutagenic, and antiobesity; however, the effects of fucoxanthin on VEGF-mediated angiogenesis and its possible binding with VEGF are unknown. Here, different lines of evidence supported the suppressive roles of fucoxanthin in VEGF-mediated angiogenesis. In human umbilical vein endothelial cells, fucoxanthin remarkedly suppressed VEGF-mediated cell proliferative, migration, and invasive abilities, as well as tube formation, without cytotoxicity. In addition, fucoxanthin inhibited the subintestinal vessel formation of zebrafish in vivo. In signaling cascades, fucoxanthin was proposed to interact with VEGF, thus attenuating VEGF's functions in activating the VEGF receptor and its related downstream signaling, i.e., phosphorylations of MEK and Erk. Fucoxanthin also significantly blocked VEGF-triggered ROS formation. Furthermore, the outcomes of applying fucoxanthin in cancer cells were identified, which included (i) inhibiting VEGF-mediated cell proliferation and migration and (ii) inhibiting NF-κB translocation via limiting MMP2 expression. These lines of investigations supported the antiangiogenic roles of fucoxanthin, as well as reviewing its signaling mechanisms, in blocking the VEGF-triggered responses. The results would benefit the potential development of fucoxanthin for the prevention and treatment of angiogenesis-related diseases.

Mapping the cellular expression patterns of vascular endothelial growth factor aa and bb genes and their receptors in the adult zebrafish brain during constitutive and regenerative neurogenesis

The complex interplay between vascular signaling and neurogenesis in the adult brain remains a subject of intense research. By exploiting the unique advantages of the zebrafish model, in particular the persistent activity of neural stem cells (NSCs) and the remarkable ability to repair brain lesions, we investigated the links between NSCs and cerebral blood vessels. In this study, we first examined the gene expression profiles of vascular endothelial growth factors aa and bb (vegfaa and vegfbb), under physiological and regenerative conditions. Employing fluorescence in situ hybridization combined with immunostaining and histology techniques, we demonstrated the widespread expression of vegfaa and vegfbb across the brain, and showed their presence in neurons, microglia/immune cells, endothelial cells and NSCs. At 1 day post-lesion (dpl), both vegfaa and vegfbb were up-regulated in neurons and microglia/peripheral immune cells (macrophages). Analysis of vegf receptors (vegfr) revealed high expression throughout the brain under homeostatic conditions, with vegfr predominantly expressed in neurons and NSCs and to a lower extent in microglia/immune cells and endothelial cells. These findings were further validated by Vegfr3 and Vegfr4 immunostainings, which showed significant expression in neurogenic radial glial cells.Following brain lesion (1 dpl), while vegfr gene expression remained stable, vegfr transcripts were detected in proliferative cells within the injured parenchyma. Collectively, our results provide a first overview of Vegf/Vegfr signaling in the brain and suggest important roles for Vegf in neurogenesis and regenerative processes.

R-954, a bradykinin B1 receptor antagonist, as a potential therapy in a preclinical endometriosis model

Endometriosis is a gynecological condition characterized by the growth of endometrium-like tissues outside of the uterine cavity. Currently available drugs are efficacious in treating endometriosis-related pain, however it’s not a targeted treatment. The aim of this work is to evaluate the effects of R-954, a bradykinin B1 receptor antagonist, in a murine model of endometriosis. The model was induced in animals through autologous transplantation of part of the uterine horn. After 51 days, it was observed that implants developed into endometriotic lesions. The administration of R-954 or progesterone, for 15 consecutive days, prevented the progression of cyst development, reduced the size and weight of the cysts. Both treatments also reduced cellular infiltrate and production of inflammatory mediators (interleukin-1β, interleukin-6, tumor necrosis factor). However, only R-954 decreased angiogenic factors (VEGF and VEGF receptor). In addition, treatment with the antagonist did not interfere in the females’ estrous cycle, as well as prevented gestational losses (reduction in the number of intermediate resorptions in pregnant females with endometriosis). Data suggested that R-954 has anti-inflammatory and anti-angiogenic effects; does not influence the estrous cycle; and prevents the number of gestational losses suggesting it as a good candidate for endometriosis treatment.