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Objective: In advanced ovarian cancer, the majority of patients receive anti-angiogenic treatment with bevacizumab. However, its use is often associated with severe side effects, and not all patients benefit from the therapy. Currently, there are no reliable biomarkers to predict response to treatment. Given their role as key regulators of angiogenesis, platelet-derived growth factor receptor-beta (PDGFR-beta) and vascular endothelial growth factor receptor-2 (VEGFR-2) are promising candidates for predictive biomarkers. This study evaluates their potential. Methods: PDGFR-beta and VEGFR-2 expression was evaluated using immunohistochemistry in a tissue microarray assay including 391 ovarian tissue samples. Correlation analyses with clinical and histopathological parameters were performed in a homogeneous cohort of 199 high grade serous ovarian cancer samples (HGSOC). Results: In HGSOC, strong stromal PDGFR-beta expression was associated with significantly shorter overall survival compared to weak/moderate expression. The impact of stromal PDGFR-beta expression on patient survival was however not restricted to the subgroup of patients receiving therapy with bevacizumab, and therefore cannot be considered as a predictive factor. For VEGFR-2, no or weak protein expression was found in the majority of the tumor samples. Survival analyses showed a more favorable prognosis with no or weak VEGFR-2 expression. Conclusions: High stromal expression levels of PDGFR-beta correlate with shorter overall survival in HGSOC. Thus, stromal PDGFR-beta might serve as a prognostic biomarker. No predictive effect in response to bevacizumab therapy could be attributed. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor is an angiogenic that promotes the development and metastasis of tumors (VEGF). The epidermal growth factor receptor, or EGFR, controls the division, growth, and death of cells via several signaling pathways. It has been found that most of the tyrosine kinase EGFR/VEGFR-2 inhibited by drugs that the FDA has approved are so far. The main objective of the present study was to identify an efficacious and selective dual inhibitor of VEGFR-2/EGFR for the treatment of cancer. Out of the 400 ligands tested against the kinases, 12 compounds demonstrated the best docking scores through molecular docking for the two kinases. Of these, only compound SCHEMBL2435814 inhibited the kinases with the highest score values when compared to a reference, vandetanib, as a dual inhibitor of EGFR/VEGFR-2 kinases through interaction with the identified active sites pocket. Following drug-likeness score toxicity and pharmacokinetic testing, the two compounds, SCHEMBL2435814 and vandetanib, were analyzed to determine how the two kinases interacted with each other. The results of calculations of π-cation interactions, hydrogen bonds, and hydrophobic interactions demonstrated a strong interaction between the two kinases and SCHEMBL2435814. Eventually, molecular dynamic modeling was used to assess the stability of complexes. This demonstrated many characteristics, including RMSF, RMSD, SASA, RG, and H-bond analysis, which demonstrated that SCHEMBL2435814 with the two kinases was more stable than vandetanib over a 100ns simulation period. By suppressing EGFR/VEGFR-2, chemical SCHEMBL2435814 may be able to postpone the signaling pathway of proteins that are essential to the advancement of cancer. [ABSTRACT FROM AUTHOR]

Background: Cancer is the predominant cause of mortality and a remarkable obstacle to elevating life anticipation in every nation on globe. Hepatocellular carcinoma (HCC), a hyper-vascular tumour, develops and progresses due to angiogenesis, a key feature of malignancy. HCC exhibits high neoangiogenic activity because of the need to generate new blood vessels for tumour growth. Methods: The present work includes the construction of virtual library of ligands, virtual screening using the Dockthor-VS server, ADMET study using the SwissADME and Osiris property explorer. All the synthesized compounds were characterized by UV, IR, NMR and mass spectroscopic techniques. MTT assay was done to find the IC50 of the synthesized compounds against HepG2 cell line. The more active compound found is subjected to the molecular dynamics simulation study. Results: The ligands exhibited good docking scores, ADMET profile compared to the reference drugs. The target compounds were obtained with the satisfactory yields of 66–82%. The best activity against the HepG2 cancer cell line is observed with the compound SA-4 with IUPAC name (2-(3-methyl-2-oxoquinoxalin-1(2H)-yl)-N-(5-(3-nitrophenyl)-5H-thiazolo[4,3-b] [1,3,4] thiadiazol-2-yl) acetamide). The experimental results obtained show correlation with the in silico results. MD simulation of the compound SA-4 indicates the moderate stability of the protein-ligand complex in real time environment. Conclusion: The results obtained suggest that the compound SA-4 has the potential to be a promising anticancer agent effective against the VEGFR-2 and FGFR-4. [ABSTRACT FROM AUTHOR]

A series of novel thiazolinone derivatives have been synthesized and characterized, and their biological activities have been studied. The title compounds were synthesized by condensation of different aldehydes 11a–11e with thiosemicarbazide to give thiosemicarbazones 12a–12e, which were cyclized with ethyl bromoacetate in the presence of sodium acetate to afford new thiazolinone derivatives 13a–13e. The structure of all newly synthesized compounds was elucidated by elemental analysis and FT–IR and multinuclear NMR (1H and 13C) spectroscopy. Newly synthesized compounds 13a–13e showed weak or no antimicrobial activity against bacterial strains Escherichia coli and Staphylococcus aureus and fungal strain Candida albicans. Furthermore, the ADME properties of compounds 13a–13e were examined, and derivatives 13a and 13b but not 13c–13e were found to conform to Lipinskiʼs and Veberʼs rules without violations. The promising compounds 13a and 13b were docked against EGFR and VEGFR-2 binding sites with reduced energy scores, higher fitting, and stability. [ABSTRACT FROM AUTHOR]

Renal cell carcinoma is a highly vascular tumor associated with vascular endothelial growth factor (VEGF) expression. The Vascular Endothelial Growth Factor -2 (VEGF-2) and its receptor was identified as a potential anti-cancer target, and it plays a crucial role in physiology as well as pathology. Inhibition of angiogenesis via blocking the signaling pathway is considered an attractive target. In the present study, 150 FDA-approved drugs have been screened using the concept of drug repurposing against VEGFR-2 by employing the molecular docking, molecular dynamics, grouping data with Machine Learning algorithms, and density functional theory (DFT) approaches. The identified compounds such as Pazopanib, Atogepant, Drosperinone, Revefenacin and Zanubrutinib shown the binding energy − 7.0 to − 9.5 kcal/mol against VEGF receptor in the molecular docking studies and have been observed as stable in the molecular dynamic simulations performed for the period of 500 ns. The MM/GBSA analysis shows that the value ranging from − 44.816 to − 82.582 kcal/mol. Harnessing the machine learning approaches revealed that clustering with K = 10 exhibits the relevance through high binding energy and satisfactory logP values, setting them apart from compounds in distinct clusters. Therefore, the identified compounds are found to be potential to inhibit the VEGFR-2 and the present study will be a benchmark to validate the compounds experimentally. [ABSTRACT FROM AUTHOR]

A method was proposed for the synthesis of some new molecular hybrids containing quinoline, 1,2,3-triazole and barbituric acid residues via Knoevenagel condensation, O-prorgylation and copper(I)-catalyzed azide alkyne cycloaddition reactions. The fourteen compounds were screened for the anticancer activity against MCF-7, MDA-MB-468 and MDA-MB-231 cell lines using MTT assay. Some compounds were screened for inhibitory activity against tyrosine kinase EGFR. Finally, in silico studies like molecular docking on EGFR and VEGFR-2 and ADMET have supported the in vitro results. [ABSTRACT FROM AUTHOR]

The coumarin nucleus is a simple privileged scaffold distributed in many plants. It has recently gained attention for its diverse biological activities and interactions with enzymes and receptors. The vascular endothelial growth factor receptor-2 (VEGFR-2), a receptor tyrosine kinase, is a crucial cancer target as it is involved in angiogenesis. This study employs virtual screening, molecular docking, and molecular simulation studies to identify potential coumarin candidates against VEGFR-2 from the COCONUT database. After thorough docking studies, CNP0056360, CNP0340213, and CNP0366287 were identified as final hits. Molecular dynamics simulation studies revealed strong stability and better binding energies for CNP0056360 and CNP0340213, outperforming lenvatinib; CNP0366287 showed comparable behaviour. The identified coumarins exhibited good in-silico pharmacokinetics and demonstrated low toxicity. [ABSTRACT FROM AUTHOR]

VEGFR-2 kinase inhibitors are clinically approved drugs that can effectively target cancer angiogenesis. However, such inhibitors have adverse effects such as skin toxicity, gastrointestinal reactions and hepatic impairment. In this study, machine learning and Topomer CoMFA, which is an alignment-dependent, descriptor-based method, were employed to build structural activity relationship models of potentially new VEGFR-2 inhibitors. The prediction ac-curacy of the training and test sets of the 2D-SAR model were 82.4 and 80.1%, respectively, with KNN. Topomer CoMFA approach was then used for 3D-QSAR modeling of VEGFR-2 inhibitors. The coefficient of q2 for cross-validation of the model 1 was greater than 0.5, suggesting that a stable drug activity-prediction model was obtained. Molecular docking was further performed to simulate the interactions between the five most promising compounds and VEGFR-2 target protein and the Total Scores were all greater than 6, indicating that they had a strong hydrogen bond interactions were present. This study successfully used machine learning to obtain five potentially novel VEGFR-2 inhibitors to increase our arsenal of drugs to combat cancer. [ABSTRACT FROM AUTHOR]

A receptor-based pharmacophore model describing the binding features required for the multi-kinase inhibition of the target kinases (VEGFR-2, FGFR-1, and BRAF) were constructed and validated. It showed a good overall quality in discriminating between the active and the inactive in a compiled test set compounds with F1 score of 0.502 and Mathew's correlation coefficient of 0.513. It described the ligand binding to the hinge region Cys or Ala, the glutamate residue of the Glu-Lys αC helix conserved pair, the DFG motif Asp at the activation loop, and the allosteric back pocket next to the ATP binding site. Moreover, excluded volumes were used to define the steric extent of the binding sites. The application of the developed pharmacophore model in virtual screening of an in-house scaffold dataset resulted in the identification of a benzimidazole-based scaffold as a promising hit within the dataset. Compounds 8a-u were designed through structural optimization of the hit benzimidazole-based scaffold through (un)substituted aryl substitution on 2 and 5 positions of the benzimidazole ring. Molecular docking simulations and ADME properties predictions confirmed the promising characteristics of the designed compounds in terms of binding affinity and pharmacokinetic properties, respectively. The designed compounds 8a-u were synthesized, and they demonstrated moderate to potent VEGFR-2 inhibitory activity at 10 µM. Compound 8u exhibited a potent inhibitory activity against the target kinases (VEGFR-2, FGFR-1, and BRAF) with IC50 values of 0.93, 3.74, 0.25 µM, respectively. The benzimidazole derivatives 8a-u were all selected by the NCI (USA) to conduct their anti-proliferation screening. Compounds 8a and 8d resulted in a potent mean growth inhibition % (GI%) of 97.73% and 92.51%, respectively. Whereas compounds 8h, 8j, 8k, 8o, 8q, 8r, and 8u showed a mean GI% > 100% (lethal effect). The most potent compounds on the NCI panel of 60 different cancer cell lines were progressed further to NCI five-dose testing. The benzimidazole derivatives 8a, 8d, 8h, 8j, 8k, 8o, 8q, 8r and 8u exhibited potent anticancer activity on the tested cell lines reaching sub-micromolar range. Moreover, 8u was found to induce cell cycle arrest of MCF-7 cell line at the G2/M phase and accumulating cells at the sub-G1 phase as a result of cell apoptosis. [ABSTRACT FROM AUTHOR]

VEGFR-2 is required for tumor angiogenesis and metastasis. As a cancer therapeutic strategy, blocking VEGFR-2 signaling pathway has gained much interest. Our work aimed to design and synthesize two series of new tolfenamic acid (TA) derivatives containing hydrazine-1-carbothioamide (compounds 4A-E) or 1,3,4-oxadiazole (compounds 5A-E) as possible VEGFR-2 tyrosine kinase inhibitors. The designed compounds were successfully synthesized using conventional organic chemical methods. Docking studies were performed to learn how the newly synthesized compounds bind to VEGFR-2 tyrosine kinase. The new compounds were evaluated in vitro for their cytotoxic activity against three human cancer cell lines. Cell cycle progression and induction of apoptosis by flow cytometry and immunoblotting were investigated. Molecular modeling showed that compounds 4A, 4B, 4C, 5A, and 5B have high docking score (ΔG) in the active pocket of the molecular target VEGFR-2. The new TA derivatives also showed good pharmacokinetic characteristics. Compound 4B, the most potent cytotoxic TA derivative, was found to have an EC50 value comparable to that of sorafenib against VEGFR-2, causing cell cycle arrest at the G2/M phase and induction of the extrinsic and endoplasmic reticulum apoptosis pathways. In summary, compound 4B has the potential to be an antagonist of VEGFR-2, which is overexpressed in solid tumors. [ABSTRACT FROM AUTHOR]

A series of the 2-nitrochalcones 3a–3k was synthesized and evaluated for cytotoxicity against the human lung adenocarcinoma (A549) and human embryonic kidney (HEK293-T) cell lines using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The 3-(4-fluorophenyl) 3c and the 3-(4-(1,1,2,2-tetrafluoroethoxy)phenyl derivative 3k induced early (25–29%) and late (48–60%) apoptosis of A549 cells as determined by the Annexin V-FITC/PI method. The 3-(4-fluorophenyl) 3c, 3-(4-methoxyphenyl) 3h, 3-(2,3,4-trimethoxyphenyl) 3j and the 3-(4-(1,1,2,2-tetrafluoroethoxy)phenyl derivative 3k were also found to exhibit significant inhibitory activity against vascular endothelial growth factor receptor-2 (VEGFR-2) tyrosine kinase compared to staurosporine (0.035 ± 0.002 µM) or nintedanib (IC50 = 0.021 ± 0.001 µM) with IC50 values of 31.49 ± 0.02, 39.95 ± 0.17, 36.90 ± 0.16 and 29.10 ± 0.16 µM, respectively. Molecular docking studies were also conducted on 3c and 3k as representative models to recognize the hypothetical binding motif of the title compounds within the active site of VEGFR-2. [ABSTRACT FROM AUTHOR]

Background: The vascular endothelial growth factor receptor-2 (VEGFR-2) plays an important role in melanoma development and progression. Peptide vaccines have shown great potential in cancer immunotherapy by targeting VEGFR-2 as a tumor-associated antigen and boosting the immune response against both tumor cells and tumor endothelial cells. Despite this, the low efficiency of peptide vaccines has resulted in moderate therapeutic results in the majority of studies. Enhancing the delivery of peptide vaccines using nanoliposomes is an important strategy for improving the efficacy of peptide vaccines. In this regard, we designed VEGFR-2-derived peptides restricted to both mouse MHC I and human HLA-A*02:01 using immunoinformatic tools and selected three peptides representing the highest binding affinities. The peptides were encapsulated in nanoliposomal formulations using the film method plus bath sonication and characterized for their colloidal properties. Results: The mean diameter of peptide-encapsulated liposomes was around 135 nm, zeta potential of − 17 mV, and encapsulation efficiency of approximately 70%. Then, vaccine formulations were injected subcutaneously in mice bearing B16F10-established melanoma tumors and their efficiency in triggering immunological, and anti-tumor responses was evaluated. Our results represented that one of our designed VEGFR-2 peptide nanoliposomal formulations (Lip-V1) substantially activated CD4+ (p < 0.0001) and CD8+ (P < 0.001) T cell responses and significantly boosted the production of IFN-γ (P < 0.0001) and IL-4 (P < 0.0001). Furthermore, this formulation led to a significant decrease in tumor volume (P < 0.0001) and enhanced survival (P < 0.05) in mice. Conclusion: Our findings suggest that the nanoliposomal formulation containing VEGFR-2 peptides could be a promising therapeutic vaccination approach capable of eliciting strong antigen-specific immunologic and anti-tumor responses. [ABSTRACT FROM AUTHOR]

Renal cell carcinoma (RCC) is the most fatal tumor in the urinary system. Resistance development and unmet effective responses, request new anticancer agents with better therapeutic index. Ten new imino-thiazolo-quinoxaline derivatives (5a-j) were synthesized and preliminary evaluated for downregulation of Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) activity taking sorafenib as a reference drug. Compounds 5d & 5h showed potent inhibition to VEGFR-2 activity at IC50 89.35 nM & 60.64 nM, respectively, then they both were further evaluated in-vitro against urinary bladder cancer cell line T-24 taking sorafenib as a reference drug. Compound 5h displayed nearly anticancer activity to sorafenib against T-24 cell line in all concentrations tested except at concentration 10 µM where it highly suppressed cell viability to 6.71 % compared to 15.15% of sorafenib. Compound 5h was then evaluated for its ameliorative efect against radiation induced renal tissue injury. Assessment of pro-angiogenic (VEGFR-2), pro-fibrotic (transforming growth factor-beta 1 (TGF-β1)) and apoptotic (caspase-3) markers, as well as histopathological examinations were performed on kidney of irradiated mice. Results showed ability of compound 5h to downregulate VEGFR-2 activity and its cytotoxic effect against RCC, in addition to mitigation of radiation induced renal tissue injury. Ethyl imino-thiazoloquinoxaline carboxylate derivative 5h showed a potential cytotoxic activity against RCC and could be considered a promosing alleviative candidate when employed post radiotherapy regimen. [ABSTRACT FROM AUTHOR]

Resent study suggests that c-kit+ cells in bone marrow-derived MSCs may differentiate toward cardiamyocytes. However, the properties of c-kit+ MSCs remain unclear. This study isolated c-kit+VEGFR-2+ cells from rat bone marrow-derived MSCs, and assessed potential of c-kit+VEGFR-2+ MSCs to differentiate towards cardiovascular cells and their efficiency of repairing the infarcted myocardium after transplantation. Gene expression profile of the cells was analyzed with RNA-sequencing. Potential of differentiation of the cells was determined after induction. Rat models of myocardial infarction were established by ligation of the left anterior descending coronary artery. The cells were treated with hypoxia and serum deprivation for four hours before transplantation. Improvement of cardiac function and repair of the infarcted myocardium were assessed at four weeks after transplantation. Gene expression profile revealed that c-kit+VEGFR-2+ MSCs expressed most smooth muscle-specific and myocardium-specific genes, while expression of endothelium-specific genes was upregulated significantly. After induction with VEGF or TGF-β for two weeks, the cells expressed CD31 and α-SMA respectively. At three weeks, BMP-2-induced cells expressed cTnT. After transplantation of the cells, cardiac function was improved, scar size of the infarcted myocardium was decreased, and angiogenesis and myocardial regeneration were enhanced significantly. Moreover, paracrine in the myocardium was increased after transplantation. These results suggest that c-kit+VEGFR-2+ MSCs have a potential of differentiation towards cardiovascular cells. Transplantation of c-kit+VEGFR-2+ MSCs is effective for repair of the infarcted myocardium. c-kit+VEGFR-2+ MSCs may be a reliable source for cell therapy of ischaemic diseases. [ABSTRACT FROM AUTHOR]

Background: Inhibition of vascular endothelial growth factor receptor 2 (VEGFR-2) tyrosine kinase by small molecules has become a promising target in the treatment of cancer. Objective: In this study, we approached pharmacophore modeling coupled with a structure-based virtual screening workflow to identify the potent inhibitors. Methods: The top selected hit compounds have been rescored using the MM/GBSA approach. To understand the molecular reactivity, electronic properties, and stability of those inhibitors, we have employed density functional theory and molecular dynamics. Following that, the best 21 hit compounds have been further post-processed with a Quantum ligand partial charge-based rescoring process and further validated by implementing molecular dynamics simulation. Results: The ten hit compounds have been hypothesized and considered as potent inhibitors of VEGFR-2 tyrosine kinase. This study also signifies the contribution of QM-based ligand partial charge, which is more accurate in predicting reliable free binding energy and filtering large ligand libraries to hit optimization, rather than assigning those of the force field-based method. From the binding pattern analysis of all the complexes, amino acids, such as Glu885, Cys919, Cys1045, Thr916, Thr919, and Asp1046, were found to have comprehensive interaction with the hit compounds. Conclusion: Hence, this could prove to be useful as a potential inhibition site of the VEGFR-2 tyrosine kinase domain for future researchers. Moreover, this study also emphasizes the conformational changes upon ATP binding, based on either the receptor's rigidity or flexibility. [ABSTRACT FROM AUTHOR]

A series of benzimidazole-tethered pyrrolones and N-benzylpyrrolones were synthesized, charac-terized, and explored for their in vitro anti-proliferative activities. The cytotoxicity of the synthesized com-pounds was evaluated against three cancer cell lines, A549, MCF7, and DU145. (E)-5-(1H-Benzimidazol-2-yl)-3-(3,4,5-trimethoxbenzylidene)-1H-pyrrol-2(3H)-one having three methoxy groups at 3,4,5-positions exhibited excellent activity against A549, MCF7, and DU145 cancer cell lines with IC50 values of 8.3±0.53, 7.2±1.42, and 7.7±0.13 µM, respectively. Another pyrrolone derivative with one hydroxy and one methoxy substituents, (E)-5-(1H-benzimidazol-2-yl)-3-(4-hydroxy-3-methoxybenzylidene)-1H-pyrrol-2(3H)-one, also displayed very good activity against A549, MCF7, and DU145 cell lines with IC50 values of 9.6±0.12, 7.3±0.24, and 8.7± 0.24 µM, respectively. Molecular docking study revealed that all compounds fit into the pocket of VEGFR-2 within the key amino acid residues Glu885, Cys919, and Asp1046. The docking scores and binding energies were very consistent with the experimental anticancer activity. Pharmacokinetic (ADME) parameters of the potent derivatives were also found to be within an acceptable range. It could be concluded that benzimidazole-linked pyrrolones are more potent than their benzylpyrrolone analogs, and therefore this class of compounds could be explored further for the development of potent anticancer agents. [ABSTRACT FROM AUTHOR]

A new series of thiourea or thioacetamide linked quinazoline derivatives has been synthesized and tested for cytotoxicity against the HCT116 and MCF-7 cell lines. Compound 10b, demonstrates strong antiproliferative effect against both colon HCT-116 and MCF-7 cell lines. Compound 10b interrupts the HCT-116 cell cycle at the G2/M phase. According to DNA flow cytometry and annexin test, hybrid 10b is also capable of inducing cell cycle disruption and apoptosis in HCT-116 cells. It causes apoptosis by activating caspases-3, increasing proapoptotic Bax and p53 levels, and decreasing Bcl-2 protein levels. As a result, the novel derivative 10b may be regarded as a promising lead to antitumor agents development. [ABSTRACT FROM AUTHOR]

Sunitinib is a potent anti-cancer scaffold that acts as a VEGFR-2 inhibitor. Although the scaffold exhibits potent anti-cancer activity, it is cardiotoxic and also induces hypothyroidism. The current research aims to optimize the Sunitinib for cardio-toxicity and thyro-toxicity by scaffold hopping approach using the admetSAR server. The server has optimized the physico-chemical properties of Sunitinib, which were contributing to the cardiotoxicity and thyro-toxicity. The library of the optimized compounds was further screened by the molecular docking studies and results were validated by the MD simulation and DFT analysis for VEGFR-2 inhibition. Compounds 163 and 432 exhibited the highest affinity to VEGFR-2 receptor with minimal cardiotoxicity and thyro-toxicity. These two compounds could be the starting point for the further discovery of angiogenic inhibitors. [ABSTRACT FROM AUTHOR]

The synthesis and evaluation of some bioisosteres of thalidomide metabolites for antiangiogenic and anticancer activity on multiple myeloma are described in this article. Four compounds, diethyl 2-(thiophene-2-sulfonamido) pentanedioate, N1,N5-diethyl-2-(thiophene-2-sulfonamido) pentanediamide, N1,N5-dihexyl-2-(thiophene-2-sulfonamido) pentanediamide, and N-(1,5-dioxo-1,5-bis(2-phenylhydrazinyl)pentan-2-yl)thiophene-2-sulfonamide exhibit cytotoxic effect on human multiple myeloma cell line (RPMI8226) with IC50 (in μM) values 3.33, 0.75, 1.23, and 3.28, respectively. The in vitro studies on human umbilical vein endothelial cells (HUVEC) and normal African green monkey kidney epithelial cells (Vero cell line) concluded that these compounds bear antiangiogenic properties and are selectively cytotoxic to cancer cells. Except for N-(1,5-dioxo-1,5-bis(2-phenylhydrazinyl)pentan-2-yl)Thiophene-2-sulfonamide, it was found to be toxic to normal epithelial cells. The "trypan blue" dye exclusion method was used to conduct an antiproliferative assay of the active compounds on HUVECs. The phosphorylation inhibition assay on Vascular Endothelial Growth Factor Receptor-2 Tyr-1175 (VEGFR-2 Tyr-1175) revealed that N1,N5-diethyl-2-(thiophene-2-sulfonamido) pentanediamide and N1,N5-dihexyl-2-(thiophene-2-sulfonamido) pentanediamide are active, indicating that the molecules have antiangiogenic activity by targeting VEGFR-2 Tyr-1175, a key autophosphorylation site that regulates pro-angiogenic responses. On CDOCKER, a molecular docking study of the most active compound N1,N5-diethyl-2-(thiophene-2-sulfonamido) pentanediamide with VEGFR-2 revealed that they might interact with the essential amino acid residues, with a binding energy of –105.304 kcal/mol. [ABSTRACT FROM AUTHOR]

Novel quinazoline derivatives have been designed, synthesized and tested for cytotoxic activity against HCT116, and MCF-7 cell lines. The preliminary data indicate their promising antitumor potential. Enzyme inhibitory activity of the most active product against VEGFR-2 has been assessed. Apoptosis and cell cycle arrest during the G2/M phase has been triggered by the product, and according to the gene expression data, it increases BAX and caspase-3 expression while decreasing Bcl-2 expression. [ABSTRACT FROM AUTHOR]

[Display omitted] Non-small cell lung cancer (NSCLC) is among the main causes of mortality from cancer around the globe, affecting all genders. Current treatments mainly focus on tyrosine kinase inhibitors (TKIs) targeting the epidermal growth factor receptor (EGFR). However, resistance mechanisms, such as the emergence of T790M and C797S EGFR mutations and upregulation of VEGFR-2, often hinder the effectiveness of TKIs. Thereby, EGFR and VEGFR-2 present an intriguing opportunity for the treatment of NSCLC by developing dual-acting drugs. This research aims to evaluate prospective Moringa oleifera L. (MO)-originated compounds to efficiently block both of these receptors. In our research, we screened a library of 200 compounds sourced from MO, a plant known for its remarkable therapeutic potential. We identified five intriguing phytocompounds: hesperetin, gossypetin, quercetin, gallocatechin, and epigallocatechin, as potential anti-cancer agents. The compounds have demonstrated notable binding affinity in virtual screening and multi-stage molecular docking analysis, surpassing the controls, Erlotinib and Bevacizumab + Rituximab. In addition, these compounds demonstrate top-notch drug-likeness and ADMET properties. The five promising drug candidates also had a strong ability to bind to receptors and stayed stable with them during the 200 ns molecular dynamics (MD) simulation and MM-GBSA calculation. Furthermore, DFT analysis indicates that hesperetin, gossypetin, and quercetagetin stand out as the most promising drug candidates among all others. The findings of our study suggest that these three therapeutic candidates can precisely target both EGFR and VEGFR-2 and can potentially act on both of these pathways as a single agent. [ABSTRACT FROM AUTHOR]

New 15 compounds have been synthesized targeting the highly conserved active site of VEGFR-2. Some of those have exhibited high anti-proliferation potency against tumor cells and inhibitory activity against VEGFR-2. One of the products (6h) has displayed the most efficient cytotoxic activity against Hela cell line invitro (IC50 = 6.10 μM) and VEGFR-2 kinase activity (IC50 = 483.1 nM). Molecular docking analysis has indicated 6h as a Type-II inhibitor of VEGFR-2 kinase. In general, the accumulated data prove 3,4-dihydroquinazolin-8-yl-3-phenylurea derivatives to be promising inhibitors of VEGFR-2 for the potential treatment of anti-angiogenesis. [ABSTRACT FROM AUTHOR]

The vascular endothelial growth factor (VEGF) is the main target of tumor treatment. VEGFR-2 is the main functional receptor of VEGF, which is involved in the regulation of angiogenesis. Based on hologram quantitative structure activity relationships (HQSAR) and topomer comparative molecular field analysis (topomer CoMFA), the contribution of 6-amide-2-aryl benzoxazole/benzimidazole derivatives (VEGFR-2 kinase inhibitors) to these structures was discussed and the corresponding modification strategies were proposed. The most effective HQSAR and topomer CoMFA models are generated by using a training set of 33 compounds. In order to ensure the robustness of the model, the randomization test was used, and 11 compounds were selected as the test set. The results show that the q2 of cross-validation is 0.646/0.659, and the r2 of non-cross-validation is 0.871/0.867, respectively. The data show that both models are reliable. Topomer CoMFA's steric/electrostatic contour and HQSAR's atomic contribution map show the structural characteristics controlling its inhibition ability. In addition, molecular docking is also used to study the interaction between these drugs and large proteins, and the ligand pair is connected to the active site of VEGFR-2 kinase, revealing the possible biological active conformation. This study showed that there was a wide interaction between 6-amide-2-aryl benzoxazole/benzimidazole derivatives and Hrg136 and Tyr356 residues of VEGFR-2 kinase active site. Finally, we used ADMET properties and drug-like properties to predict the newly designed molecules, and the results showed that they meet the conditions for becoming drugs and are expected to become potential anti-VEGFR-2 inhibitors. This study can provide a theoretical reference for the synthesis of target products of VEGFR-2 inhibitors. [ABSTRACT FROM AUTHOR]

VEGFR-2 inhibition represents an attractive strategy for anticancer drug design. A new series of quinoline derivatives were synthesized and structurally confirmed with different spectroscopic techniques. VEGFR-2 inhibition assay showed that 2-(4-bromoquinolin-3-yloxy)-1-(4-chlorophenyl)ethanone (V) demonstrated potent VEGFR-2 inhibitory activities. In addition, the brominated quinoline (V) exhibit antitumor activity over MCF-7 cell line via cell cycle arrest at G1 phase and apoptosis inducing activity as revealed by cell cycle analysis and Annexin V/FITC staining assays. Moreover, brominated quinoline (V) was proved to upregulate expression of proteins that trigger apoptosis such as increased Bax, decreased Bcl-2 as well as increased Bax/Bcl-2 ratio. [ABSTRACT FROM AUTHOR]

Background: Near-infrared photoimmunotherapy (NIR-PIT) constitutes a new class of molecular-targeted theranostics utilizing monoclonal antibody (mAb)-photosensitizer conjugates and NIR light. In this study, we developed a new type of NIR-PIT targeting vascular endothelial growth factor receptor 2 (VEGFR-2) expressed on vascular endothelium in an experimental gastric cancer model and evaluated the feasibility by comparing conventional NIR-PIT targeting cancer cell membrane in vitro and in vivo. Methods: HER2-positive human gastric cancer cells, NCI-N87, were used for the experiments. Anti-HER2 mAb, trastuzumab and anti-VEGFR-2 mAb, DC101 were conjugated to photosensitizer, IR700. Phototoxicity in response to NIR-PIT were investigated in vitro and in vivo. Microvessel densities, as an indicator of angiogenesis, were counted in harvested xenografts after NIR-PIT to elucidate the mechanism. Results: DC101-IR700 did not induce phototoxic effect in vitro because of the absence of expression of VEGFR-2 in NCI-N87 cancer cells. However, it induced an antitumor effect in NCI-N87 xenograft tumors accompanied with damage in tumor neovasculature as determined by decreasing tumor microvessel density, which represents a different mechanism than that of conventional NIR-PIT targeting antigens expressed on the tumor cell membrane. Conclusion: We demonstrated a new approach of NIR-PIT utilizing a target on vascular endothelium, such as VEGFR-2, and this treatment might lead to the development of a new therapeutic strategy for human gastric cancer. [ABSTRACT FROM AUTHOR]

Purpose: Platinum-based doublet chemotherapy and radiotherapy are the standard treatment option in advanced squamous cell carcinoma patients. However, few agents could be selected for subsequent post-second-line treatment. As a small molecule inhibitor of vascular endothelial growth factor receptor-2 tyrosine kinase, apatinib had been proved in advanced gastric cancer. Here, we showed its efficacy and safety in lung squamous cell carcinoma.Methods: In this retrospective study, 13 advanced lung squamous cell carcinoma patients were enrolled. They received doublet chemotherapy or docetaxel as the first-line treatment. After disease progressed, all patients were administrated apatinib monotherapy (250-425 mg/day) for second-line or fourth-line therapy.Results: After apatinib monotherapy, two patients achieved partial response, four patients achieved stable disease, and seven patients achieved progression disease. The medium PFS was 3.1 months. The median OS had not yet been reached. The objective remission rate was 15.4% (2/13). The total disease control rate was 46.2% (6/13). The main advert effects were vomiting and hypertension.Conclusion: Apatinib might be an option as rescue treatment in advanced lung squamous cell carcinoma. [ABSTRACT FROM AUTHOR]

WHO grade II/III meningiomas recur frequently and there is currently no established molecular target therapy for meningioma. No previous studies have revealed the association between receptor tyrosine kinases (RTKs) and the recurrence of meningiomas. This study aims to elucidate the association between RTKs and the clinicopathological characteristics and recurrence of meningioma. We investigated the immunohistochemical expression of RTKs (VEGFR-1/2/3, PDGFR-alpha/beta and c-Kit) in 81 meningiomas (WHO grade I, n = 64, WHO grade II/III, n = 17) in 74 patients. Immunohistochemistry revealed that 29 WHO grade I (45%), 10 WHO grade II (77%), and 4 WHO grade III (100%) tumors were VEGFR-2-positive, and that the VEGFR-2 expression was significantly correlated with the WHO grade. In univariate analyses to investigate the clinicopathological factors associated with recurrence, Simpson grade IV/V resection, a larger tumor size, a high VEGFR-2 expression level, WHO grade II/III, a high Ki-67 expression level, and the non-expression of PgR were identified as significant factors. Furthermore, patients with VEGFR-2-positive meningiomas showed significantly shorter progression-free survival. In the multivariate analysis, WHO grade II/III and the location were significantly associated with recurrence. In conclusion, our study suggests that VEGFR-2 inhibitors might be one of the best candidates for molecular therapy against recurrent meningiomas. [ABSTRACT FROM AUTHOR]

Recently, VEGFR-2 has been detected not only in vascular and lymphatic endothelial cells but also in some non-vascular endothelial cells, particularly human hair follicles, sebaceous glands, and sweat glands. In addition, VEGFR-2 has been confirmed to play direct roles in hair follicle keratinocyte regulation beyond simply angiogenesis. To elucidate whether VEGFR-2 activation plays a role in hair follicle cycling regulation, immunofluorescence of VEGFR-2 expression was performed during hair cycling of the dorsum of the mouse induced by hair plucking. We observed that staining for VEGFR-2 in hair follicles during anagen II and IV was much stronger than during anagen VI, catagen and telogen. During anagen II, intense staining for VEGFR-2 was observed on the keratinocyte strands of the hair follicle. Subsequently, we detected intense staining for VEGFR-2 in the ORS, IRS and hair bulb during anagen IV. Moderate staining for VEGFR-2 was detected in the ORS and hair bulb, but staining was most intense in IRS during anagen VI. During catagen, staining for VEGFR-2 in the IRS remained intense, while staining in the ORS and hair bulb was significantly weakened and was negative in the dermal papilla. During telogen, we detected VEGFR-2 in germ cells, cap, and club hair adjoining the epidermis. In conclusion, VEGFR-2 was expressed on the hair follicles of the dorsum of the mouse and varied in expression on the mouse hair follicles during hair cycling, suggesting that VEGFR-2 may exert roles in hair cycle regulation in hair follicles on the dorsum of mice. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factors (VEGFs) regulate blood and lymph vessel development upon activation of three receptor tyrosine kinases (VEGFRs). The extracellular domain of VEGFRs consists of seven Ig-homology domains, of which D2-3 form the ligand-binding site, while the membrane proximal domains D4-7 are involved in homotypic interactions in ligand-bound receptor dimers. Based on low-resolution structures, we identified allosteric sites in D4-5 and D7 of vascular endothelial growth factor receptor 2 (VEGFR-2) accomplishing regulatory functions. Allosteric inhibition of VEGFR-2 signaling represents an attractive option for the treatment of neovascular diseases. We showed earlier that DARPin® binders to domains D4 or D7 are potent VEGFR-2 inhibitors. Here we investigated in detail the allosteric inhibition mechanism of the domain D4 binding inhibitor D4b. The 2.38 Å crystal structure of D4b in complex with VEGFR-2 D4-5, the first high-resolution structure of this VEGFR-2 segment, indicates steric hindrance by D4b as the mechanism of inhibition of receptor activation. At the cellular level, D4b triggered quantitative internalization of VEGFR-2 in the absence of ligand and thus clearance of VEGFR-2 from the surface of endothelial cells. The allosteric VEGFR-2 inhibition was sufficiently strong to efficiently inhibit the growth of human endothelial cells at suboptimal dose in a mouse xenograft model in vivo, underlining the therapeutic potential of the approach. [ABSTRACT FROM AUTHOR]

In this study, a xenogeneic DNA vaccine encoding for human vascular endothelial growth factor receptor-2 (hVEGFR-2) was evaluated in two murine tumor models, the B16-F10 melanoma and the EO771 breast carcinoma model. The vaccine was administered by intradermal injection followed by electroporation. The immunogenicity and the biological efficacy of the vaccine were tested in (1) a prophylactic setting, (2) a therapeutic setting, and (3) a therapeutic setting combined with surgical removal of the primary tumor. The tumor growth, survival, and development of an immune response were followed. The cellular immune response was measured by a bioluminescence-based cytotoxicity assay with vascular endothelial growth factor-2 (VEGFR-2)-expressing target cells. Humoral immune responses were quantified by enzyme-linked immunosorbent assay (ELISA). Ex vivo bioluminescence imaging and immunohistological observation of organs were used to detect (micro)metastases. A cellular and humoral immune response was present in prophylactically and therapeutically vaccinated mice, in both tumor models. Nevertheless, survival in prophylactically vaccinated mice was only moderately increased, and no beneficial effect on survival in therapeutically vaccinated mice could be demonstrated. An influx of CD3+ cells and a slight decrease in VEGFR-2 were noticed in the tumors of vaccinated mice. Unexpectedly, the vaccine caused an increased quantity of early micrometastases in the liver. Lung metastases were not increased by the vaccine. These early liver micrometastases did however not grow into macroscopic metastases in either control or vaccinated mice when allowed to develop further after surgical removal of the primary tumor. [ABSTRACT FROM AUTHOR]

Regulator of calcineurin 1 (RCAN1) is an endogenous inhibitor of the calcineurin pathway in cells. It is expressed as two isoforms in vertebrates: RCAN1.1 is constitutively expressed in most tissues, whereas transcription of RCAN1.4 is induced by several stimuli that activate the calcineurin-NFAT pathway. RCAN1.4 is highly upregulated in response to VEGF in human endothelial cells in contrast to RCAN1.1 and is essential for efficient endothelial cell migration and tubular morphogenesis. Here, we show that RCAN1.4 has a role in the regulation of agonist-stimulated VEGFR-2 internalisation and establishment of endothelial cell polarity. siRNA-mediated gene silencing revealed that RCAN1 plays a vital role in regulating VEGF-mediated cytoskeletal reorganisation and directed cell migration and sprouting angiogenesis. Adenoviral-mediated overexpression of RCAN1.4 resulted in increased endothelial cell migration. Antisense-mediated morpholino silencing of the zebrafish RCAN1.4 orthologue revealed a disrupted vascular development further confirming a role for the RCAN1.4 isoform in regulating vascular endothelial cell physiology. Our data suggest that RCAN1.4 plays a novel role in regulating endothelial cell migration by establishing endothelial cell polarity in response to VEGF. [ABSTRACT FROM AUTHOR]

Purpose: The extracellular region (EC) of the vascular endothelial growth factor (VEGF) receptor-2 (VEGFR-2) contains seven immunoglobulin-like (Ig-like) domains that are required for specific ligand binding and receptor dimerization. Studies of domain 4-7 deletions and substitutions provided insights into the interaction between receptors in the absence of VEGF. In this study, we investigated the effect of domain 4 in ligand-independent VEGFR-2 dimerization and activation in human vascular endothelial cells and human breast cancer cells. Methods: To confirm the role of domain 4 in ligand-independent receptor dimerization and activation, two VEGFR-2 fragments with and without domain 4, KFP1 and KFP2, were generated by recombinant DNA technology. We measured the affinity of KFP1 and KFP2 with VEGFR-2, and the roles of KFP1 and FKP2 in dimerization and phosphorylation of VEGFR-2. We also evaluated the effect of KFP1 and FKP2 on cell proliferation and migration in HUVECs and in human breast cancer cells. Results: We showed that KFP1 did not affect the interaction of VEGFR-2 and VEGF but bound VEGFR-2 in the absence of VEGF. Furthermore, cross-linking and cross-linking immunoblotting demonstrated that KFP1 could form a complex with VEGFR-2, which resulted in VEGFR-2 dimerization in the absence of VEGF. Importantly, we found that the KDR fragment with domain 4 induced phosphorylation of VEGFR-2, as well as phosphorylation of downstream receptor kinases in HUVECs and VEGFR-2-positive breast cancer cells. Consistent with these results, this ligand-independent activation of VEGFR-2 also promoted downstream signaling and cell proliferation and migration. Conclusions: The domain 4 of VEGFR-2 plays an important role in the interaction between VEGFR receptors in the absence of VEGF. [ABSTRACT FROM AUTHOR]

Angiogenesis is a multistep process that plays a key role in cancer growth and metastases. It is mediated through multiple vascular endothelial growth factor receptors (VEGFRs) and their ligands. The expression of VEGFR-2 is upregulated in tumor endothelial cells, and it is considered to be the primary receptor driving malignant angiogenesis. Ramucirumab (IMC-1121B, LY3009806) is a fully human monoclonal antibody that directly binds to VEGFR-2 with high affinity and specificity. It is also the most recent addition to our armamentarium of anti-angiogenic drugs approved for the treatment of metastatic colorectal cancer (CRC). The aim of this review is to summarize the pre-clinical and clinical development of ramucirumab and discuss its place in the current treatment paradigm for metastatic CRC. [ABSTRACT FROM AUTHOR]

Purpose: Vascular endothelial growth factor receptor-2 (VEGFR-2), epidermal growth factor receptor-1 (EGFR) and cyclooxygenase-2 (COX-2) stimulate key processes involved in tumour progression and are important targets for cancer therapeutics. F-FDG maximum standardized uptake value (SUVmax) on PET/CT is a marker of tumour metabolic activity. The purpose of this study was to measure percentage reductions in SUVmax (∆SUVmax%), VEGFR-2 (∆VEGFR-2%), EGFR (∆EGFR%) and COX-2 (∆COX-2%) in patients with locally advanced rectal cancer (LARC) after preoperative treatment, and to correlate the changes in these markers of response with pathological response in terms of tumour regression grade (TRG) using Rödel's scale and long-term clinical outcome. Methods: VEGFR-2, EGFR and COX-2 were measured using a quantitative and qualitative compound immunohistochemistry analysis (immunoreactive score) of the pretreatment endoscopic biopsy and definitive surgical specimens. Composite indexes using ∆SUVmax% and the three molecules were developed to differentiate patients with metabolic and molecular responses from nonresponders. Cox proportional hazards model was used to explore associations between the tumour markers, disease-free survival (DFS) and overall survival (OS). Results: The analysis included 38 patients with a median follow-up of 86 months (range 5 - 113 months). The ∆VEGFR-2%/∆SUVmax% index correctly identified 13 of 19 pathological responders (TRG 3 and 4) and 17 of 19 nonresponders (TRG 0 - 2) (sensitivity 68 %, specificity 89 %, accuracy 79 %, positive predictive value 87 %, negative predictive value 74 %). In multivariate analysis, only the ∆VEGFR-2%/∆SUVmax% index was associated with DFS (HR 0.11, p = 0.001) and OS (HR 0.15, p = 0.02). Conclusion: In patients with LARC the ∆VEGFR-2%/∆SUVmax% response index is associated with outcome. Determination of the optimal diagnostic cut-off level for this novel biomarker association should be explored. Evaluation in a clinical trial is required to determine whether selected patients could benefit from treatment with a VEGFR-targeted therapeutic agent. [ABSTRACT FROM AUTHOR]

Viral VEGF-E (ovVEGF-E), a homolog of VEGF-A, was discovered in the genome of Orf virus. Together with VEGF-A, B, C, D, placental growth factor (PlGF) and snake venom VEGF (svVEGF), ovVEGF-E is a member of the VEGF family of potent angiogenesis factors with a bioactivity similar to VEGF-A: it induces proliferation, migration and sprouting of cultured vascular endothelial cells and proliferative lesions in the skin of sheep, goat and man that are characterized by massive capillary proliferation and dilation. These biological functions are mediated exclusively via its interaction with VEGF receptor-2 (VEGFR-2). Here, we have generated transgenic mice specifically expressing ovVEGF-E in β-cells of the endocrine pancreas (Rip1VEGF-E; RVE). RVE mice show an increase in number and size of the islets of Langerhans and a distorted organization of insulin and glucagon-expressing cells. Islet endothelial cells of RVE mice hyper-proliferate and form increased numbers of functional blood vessels. In addition, the formation of disorganized lymphatic vessels and increased immune cell infiltration is observed. Upon crossing RVE single-transgenic mice with Rip1Tag2 (RT2) transgenic mice, a well-studied model of pancreatic β-cell carcinogenesis, double-transgenic mice (RT2;RVE) display hyper-proliferation of endothelial cells resulting in the formation of hemangioma-like lesions. In addition, RT2;RVE mice exhibit activated lymphangiogenesis at the tumor periphery and increased neutrophil and macrophage tumor infiltration and micro-metastasis to lymph nodes and lungs. These phenotypes markedly differ from the phenotypes observed with the transgenic expression of the other VEGF family members in β-cells of normal mice and of RT2 mice. [ABSTRACT FROM AUTHOR]

The discovery of novel scaffolds against a specific target has long been one of the most significant but challengeable goals in discovering lead compounds. A scaffold that binds in important regions of the active pocket is more favorable as a starting point because scaffolds generally possess greater optimization possibilities. However, due to the lack of sufficient chemical space diversity of the databases and the ineffectiveness of the screening methods, it still remains a great challenge to discover novel active scaffolds. Since the strengths and weaknesses of both fragment-based drug design and traditional virtual screening (VS), we proposed a fragment VS concept based on Bayesian categorization for the discovery of novel scaffolds. This work investigated the proposal through an application on VEGFR-2 target. Firstly, scaffold and structural diversity of chemical space for 10 compound databases were explicitly evaluated. Simultaneously, a robust Bayesian classification model was constructed for screening not only compound databases but also their corresponding fragment databases. Although analysis of the scaffold diversity demonstrated a very unevenly distribution of scaffolds over molecules, results showed that our Bayesian model behaved better in screening fragments than molecules. Through a literature retrospective research, several generated fragments with relatively high Bayesian scores indeed exhibit VEGFR-2 biological activity, which strongly proved the effectiveness of fragment VS based on Bayesian categorization models. This investigation of Bayesian-based fragment VS can further emphasize the necessity for enrichment of compound databases employed in lead discovery by amplifying the diversity of databases with novel structures. [ABSTRACT FROM AUTHOR]

Expression and activation of vascular endothelial growth factor receptor 2 (VEGFR-2) by VEGF ligands are the main events in the stimulation of pathological angiogenesis. VEGFR-2 expression is generally low in the healthy adult blood vessels, but its expression is markedly increased in the pathological angiogenesis. In this report, we demonstrate that phosducin-like 3 (PDCL3), a recently identified chaperone protein involved in the regulation of VEGFR-2 expression, is required for angiogenesis in zebrafish and mouse. PDCL3 undergoes N-terminal methionine acetylation, and this modification affects PDCL3 expression and its interaction with VEGFR-2. Expression of PDCL3 is regulated by hypoxia, the known stimulator of angiogenesis. The mutant PDCL3 that is unable to undergo N-terminal methionine acetylation was refractory to the effect of hypoxia. The siRNA-mediated silencing of PDCL3 decreased VEGFR-2 expression resulting in a decrease in VEGF-induced VEGFR-2 phosphorylation, whereas PDCL3 over-expression increased VEGFR-2 protein. Furthermore, we show that PDCL3 protects VEGFR-2 from misfolding and aggregation. The data provide new insights for the chaperone function of PDCL3 in angiogenesis and the roles of hypoxia and N-terminal methionine acetylation in PDCL3 expression and its effect on VEGFR-2. [ABSTRACT FROM AUTHOR]

Introduction: Sorafenib is a strong multikinase inhibitor targeting 2 different pathways of endometriosis pathogenesis: RAF kinase and vascular endothelial growth factor receptor (VEGFR). We investigate whether Sorafenib could control the growth of endometriotic lesions both in vitro and in vivo. Methods: Stromal primary cells were extracted from endometrial and endometriotic biopsies from patients with (n = 10) and without (n = 10) endometriosis. Proliferation, apoptosis, mitogen-activated protein kinases, and VEGFR-2 autophosphorylation were explored with and without Sorafenib treatment. Human endometriotic lesions were implanted in 30 nude mice randomized according to Sorafenib or placebo treatment. Results: Treating endometriotic cells with Sorafenib abrogated the phosphorylation of extracellular signal-regulated kinase in stromal cells of women with endometriosis compared to controls. In addition, this study highlights the antiangiogenic role of Sorafenib which translates as a decreased phosphorylated VEGFR-2–VEGFR-2 ratio in endometriosis. Using a xenogenic mouse model of endometriosis, we confirmed that Sorafenib regulates the endometriosis activity in vivo by targeting endometriosis-related proliferation and inflammation. Conclusion: Our data suggest that Sorafenib controls the growth of endometriotic lesions in vitro and in vivo. [ABSTRACT FROM AUTHOR]

Background: We previously reported that dietary glucosylceramides show cancer-prevention activity in a mouse xenograft model of human head and neck cancer cells (SCCKN). However, the mechanism was unclear. Ceramides, metabolites of glucosylceramides, induce apoptotic cell death in various malignancies. Here, we investigated the inhibitory effects of dietary glucosylceramides on tumor growth in vivo and in vitro. Methods: SCCKN were subcutaneously inoculated into the right flanks of NOD/SCID mice. Mice were treated with or without dietary glucosylceramides (300 mg/kg) daily for 14 consecutive days after confirmation of tumor progression. Microvessel areas around the tumor were assessed by hematoxylin-eosin staining and immunohistochemistry of CD31, and, as markers for angiogenesis, protein levels of VEGF, VEGF receptor-2, and HIF-1α were assessed by Western blotting. Mass spectrometry was performed to measure the levels of sphingolipids in mouse serum after treatment with dietary glucosylceramides. Results: Oral administration of glucosylceramides significantly decreased SCCKN growth in the xenograft model with inhibition of angioinvasion. In tumor-invasive areas, VEGF and HIF-1α in the tumor cells, and VEGF receptor-2 in endothelial cells decreased after treatment with dietary glucosylceramides. Dietary glucosylceramides increased serum levels of sphingosine-based ceramides as compared to the control. In SCCKN and UV♀2 cells, C6-ceramide suppressed the expressions of VEGF, VEGF receptor-2, and HIF-1α in vitro. Conclusion: These results suggest that dietary glucosylceramides trigger the de novo pathway of ceramide synthesis, indicating that sphingosine-based ceramide suppresses the growth of head and neck tumors through the inhibition of pro-angiogenic signals such as VEGF, VEGF receptor-2, and HIF-1α. [ABSTRACT FROM AUTHOR]

Purpose: Angiogenesis plays a major role in tissue remodeling and repair after myocardial infarction (MI), and imaging it could provide information on the healing process. During angiogenesis, vascular endothelial growth factor receptors (VEGFRs), platelet-derived growth factor receptors (PDGFRs), and Tie receptors are upregulated, and this study aimed to develop a C-11 positron emission tomography (PET) agent for imaging angiogenesis by targeting these receptors. Procedures: A VEGFR-2/Tie-2/PDGFRα inhibitor ( N-(6-{4-[3-(2-fluoro-5-trifluoromethyl-phenyl)-ureido]-phenoxy}-1 H-benzoimidazol-2-yl)-2-(4-methyl-piperazin-1-yl)-acetamide (ATV-1)) was synthesized and labeled with C-11. MicroPET imaging of a rat MI model was compared to proteins expression by immunohistochemistry. Results: [C]ATV-1 specifically accumulated in the infracted region of the left ventricular (LV) lateral wall more than in the interventricular septal wall, but not in sham-operated or healthy animals. Moreover, [C]ATV-1 uptake in the LV significantly correlated with Tie-2, VEGFR-2, and PDGFRα expression. Conclusion: Imaging angiogenesis in MI rats using [C]ATV-1 and PET has been demonstrated. These results merit further research and development of more hydrophilic modified [C]ATV-1 as a PET tracer. [ABSTRACT FROM AUTHOR]

Purpose: Hypothyroidism is a common adverse event in patients treated with anti-VEGFR-2 targeting agents and may be a valuable predictive factor of efficacy. Famitinib is an inhibitor of multiple tyrosine kinases mainly targeting VEGFR-2. The objectives of this study were to assess the efficacy and safety of famitinib in patients with pretreated HER2-negative metastatic breast cancer (MBC) and to explore potential of famitinib-induced hypothyroidism and serum vascular endothelial growth factor (VEGF) level for efficacy prediction. Materials and methods: The primary end point was objective response rate (ORR). Famitinib was administered 25 mg/d. Thyroid function assessments were done at baseline and then every 4 weeks. Plasma levels of VEGF were determined at baseline and 2 cycles after treatment. Results: A total of 28 patients were enrolled. ORR was 14.3 %. The most common grade 3/4 AEs were hand-foot syndrome (25.0 %), proteinuria (21.4 %) and hypertension (17.9 %). 64.0 % patients were observed with elevated thyroid-stimulating hormone (TSH) (>4.94 mIU/L) at any time during the entire treatment period. Sixteen patients with an elevated TSH had a significantly longer PFS than nine patients with no TSH elevation (107 vs. 53 days, respectively, P = 0.002). TSH elevation was also an independent predictor of PFS in a Cox regression model. Plasma VEGF levels did not correlate significantly with clinical outcomes. Conclusions: Famitinib did show substantial anti-tumor activities with a good safety profile in heavily pretreated patients with HER2-negative MBC. Famitinib-related TSH increase may be an early indicator of its efficacy. Serial monitoring of serum TSH may help define VEGFR-2-dependent or VEGFR-2-independent drug resistance. [ABSTRACT FROM AUTHOR]

Purpose To investigate the efficacy and safety of combining vandetanib, an orally available multi-targeted tyrosine kinase inhibitor of vascular endothelial growth factor receptor-2 (VEGFR-2) and epidermal growth factor receptor (EGFR), with bicalutamide in patients with metastatic castration-resistant prostate cancer (mCRPC). Methods This was an open-label, randomized phase II multi-center study. Eligible patients had rising PSA on androgen deprivation therapy, minimal symptoms and were chemotherapy-naïve. Protocol therapy was either vandetanib 300 mg oral daily plus bicalutamide 50 mg oral daily (Arm A) or bicalutamide 50 mg oral daily alone (Arm B) with cross-over to vandetanib monotherapy at progression. The primary endpoint was PSA response (≥ 50 % decline from baseline). Results Thirty-nine patients were recruited, 19 in Arm A and 20 in Arm B. PSA response was comparable in Arm A and Arm B (18 vs. 19 %). Time to PSA progression was 3.16 months (95 % confidence interval (CI): 1.09, not reached (NR)) for Arm A and 3.09 months (95 % CI: 1.22, NR) for Arm B. Treatment discontinuation due to adverse events was more common in Arm A compared to Arm B (42 vs. 5 %; p = 0.019). Treatment with vandetanib was associated with a reduction in soluble VEGFR-2 levels after two cycles but an increase in plasma VEGF levels. Conclusion The combination of vandetanib and bicalutamide was associated with considerable toxicity and did not have superior efficacy over bicalutamide alone. Further evaluation of this combination is not warranted in mCRPC. [ABSTRACT FROM AUTHOR]

Purpose: Dendritic cell (DC) vaccines are a promising immunotherapeutic approach for treatment and prevention of cancer. While this methodology is widely accepted, it also has some limitations. Antigen-presenting cells including DCs express the mannan receptor (MR). The delivery of a mannan-modified tumor antigen to the MR has been demonstrated to be efficient. Vascular endothelial growth factor receptor-2 (VEGFR-2) is mainly responsible for angiogenesis and tumor growth. The goal of our study was to deliver VEGFR-2 to DCs by means of mannan-modified adenovirus. Methods: VEGFR-2 recombinant adenovirus modified with oxidized mannan was constructed as a tumor vaccine to immunize mice in vivo. IFN-γ in mouse sera and spleen was detected by ELISA and ELISPOT. The killing activity of cytotoxic T lymphocyte (CTL) against VEGFR-2 was measured with a lactate dehydrogenase assay. Vessel densities in tumor tissues were detected by immunohistochemistry. Flow cytometry was used to test CD4 and CD8 T-cell counts in tumor tissues. Results: The vaccine exhibited both protective and therapeutic efficacy in the inhibition of tumor growth and markedly prolonged survival in mice. Protection against metastasis was also observed. Furthermore, vaccination led to greater IFN-γ and VEGFR-2-specific CTLs. The specific immunity resulted in the suppression of angiogenesis and an increase in CD8 cells in tumor tissues. Conclusion: Oxidized mannan-modified adenovirus expressing VEGFR-2 could extraordinarily stimulate both protective and therapeutic immune response in a mice model. Our data suggest that the combination of cancer immunity and anti-angiogenesis via modified mannan is a promising strategy in tumor prophylaxis and therapy. [ABSTRACT FROM AUTHOR]

Low-level laser therapy (LLLT) has been widely used in the treatment of the stomatognathic system dysfunction; however, its biological effect remains poorly understood. This study evaluated the effect of LLLT (GaAlAs, 780 nm, 20 J/cm², 40 mW) on masseter muscle of HRS/J mice after different numbers of laser irradiations (three, six, and ten) for 20 s in alternate days. Three experimental groups were defined according to the number of laser irradiations and three control groups ( n = 5) were used. On the third day after the last irradiation, all animals were killed and the masseter muscle was removed and processed for the following analysis: (a) transmission electron microscopy, (b) zymography, (c) immunohistochemistry for vascular endothelial growth factor (VEGF) and VEGFR-2. The results showed: (a) with six laser applications, a dilation of T tubules, and sarcoplasmic reticulum cistern, increased pinocytosed vesicles in the endothelium; with ten laser applications, few pinocytic vesicles in the endothelium and condensed mitochondria. (b) Under the conditions of this study, the synthesis of other matrix metalloproteinases was not observed, only the MMP-2 and -9. (c) After ten laser irradiations, immunostaining was observed only for VEGFR-2. We conclude that after six laser applications, ultrastructural changes may facilitate the Ca transfer to cytosol and increase the fluid transport from one surface to another. The ultrastructural changes and no immunostaining for VEGF with ten applications may decrease the metabolic activity as well as damage the angiogenic process, suggesting that an effective number of laser applications may be less than ten, associating to this therapy a better cost-benefit. [ABSTRACT FROM AUTHOR]

This review is designed to provide an overview of the current literature concerning vascular endothelial growth factor signaling (VEGF) in acute myeloid leukemia (AML). Aberrant VEGF signaling operates in the bone marrow of AML patients and is related to a poor prognosis. The altered signaling pathway demonstrated to interfere in several autocrine and paracrine signaling pathways. VEGF signaling promotes autocrine AML blast cell proliferation, survival, and chemotherapy resistance. In addition, VEGF signaling can mediate paracrine vascular endothelial cell-controlled angiogenesis in AML. Both effects presumably explain the association of high VEGF levels and poor therapeutic outcome. More recently, researches focusing on bone marrow stem cell niches demonstrate a role for VEGF signaling in the preservation of several cell types within these niches. The bone marrow niches are proposed to be a protective microenvironment for AML cells that could be responsible for relapses in AML patients. This implies the need of sophisticated VEGF-targeted therapeutics in AML therapy strategies. This review highlights our current understanding of aberrant VEGF signaling in AML, appoints the interference of VEGF signaling in the AML-associated microenvironment, and reflects the novelty of current VEGF-targeted therapeutics used in clinical trails for the treatment of AML. [ABSTRACT FROM AUTHOR]

Tumor angiogenesis, which is an important step in the development of cancer, is directly regulated by vascular endothelial growth factor receptor 2 ( VEGFR-2). In this study, we examined the association of five potentially functional VEGFR-2 polymorphisms with glioma risk in a Chinese Han population. Three SNPs, rs2071559, rs7667298 and rs2305948, showed a statistically significant increased association with the risk of glioma ( P = 0.006, 0.005, and 0.012, respectively). Both haplotype and diplotype analyses consistently revealed that subjects carrying two copies of the haplotype 'CGT' had a 42% reduced glioma risk compared with their respective noncarriers. Our findings suggested that VEGFR-2 gene variants might contribute to glioma susceptibility. [ABSTRACT FROM AUTHOR]

Recent evidence indicates that several experimental pathophysiological conditions are associated with elevated protease activity in plasma, which impacts endothelial function. We hypothesize that extracellular structures bound to the endothelial cell (EC) membrane may be degraded by proteolytic activity reducing the cell's response to physiological shear stress and glucose metabolism efficiency. To test this hypothesis, cultured bovine aortic endothelial cells (BAECs) were exposed to low serine protease activity. Extracellular mechanosensor densities of the glycocalyx and vascular endothelial growth factor receptor 2 (VEGFR-2) were determined. Metabolic dysfunction was tested by examining insulin receptor and glucose uptake levels. Protease treatment impaired the cells' ability to align in the direction of fluid flow after 12 h of shear stress (12 dyn/cm); however, cells realigned after an additional 12 h of shear stress with protease inhibition. Proteases caused reduction in the densities of glycocalyx, VEGFR-2, and insulin receptor in static and shear conditions, except for static VEGFR-2 cells. Under static conditions, protease-treated ECs had reduced glucose uptake compared to untreated controls. Under shear, glucose uptake for protease treated BAECs was greater than untreated controls. In conclusion, protease activity in plasma alters the exofacial membrane components of ECs and may interfere with mechanotransduction. [ABSTRACT FROM AUTHOR]

We report a novel gold nanobioconjugate system that achieves targeted delivery of the small molecule drug doxorubicin to endothelial cells using anti-VEGFR-2 antibody conjugated gold nanoparticles (GNPs). The reported nanobioconjugate system combines the inherent ability of GNPs to undergo high levels of derivatization with the precision of antibody recognition of a cell surface antigen. Transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS) confirmed intracellular presence of the GNPs. Using a VEGFR-2 expressing cell line and a cell line that is negative for the receptor, in combination with competition assay we established the cell specific targeted delivery of the nanobioconjugate. The nanobioconjugate system described here may have potential drug delivery applications for antiangiogenic cancer therapy. [ABSTRACT FROM AUTHOR]

Peroxisome proliferator-activated receptor γ (PPARγ) activation has anti-angiogenic and apoptotic effects in endothelial cells. Here, we investigated the mechanisms of the anti-angiogenic action of a novel PPARγ ligand, KR-62980. KR-62980 inhibited in vitro basal tube formation and in vivo neovascularization in mice induced by Matrigel containing vascular endothelial growth factor (VEGF, 5 ng/ml). VEGF-induced cell proliferation and chemotactic migration in human umbilical vein endothelial cells (HUVECs) were also suppressed by KR-62980, in a mechanism accompanied by apoptotic cell death. KR-62980 downregulated the VEGF-induced VEGFR-2 expression but increased the phosphatase and tensin homolog deleted on chromosome 10 (PTEN) expression in parallel with reduced phosphorylation of extracellular signal-related kinase 1/2 (ERK1/2), PI3K p85α, and p38 MAPK. The knockdown of PTEN expression abolished KR-62980-suppressed cell proliferation and angiogenesis. All of the effects of KR-62980 disappeared with pretreatment of bisphenol A diaglycidyl ether (BADGE), a PPARγ antagonist. In summary, KR-62980 inhibited VEGF-induced angiogenesis in HUVECs by PPARγ-mediated dual mechanisms: VEGFR-2 downregulation and PTEN upregulation. [ABSTRACT FROM AUTHOR]

Vascular Endothelial Growth Factor Receptor (VEGFR) mediated signalling drives angiogenesis. This is predominantly attributed to the activity of VEGFR-2 following binding of VEGF-A. Whether other members of the VEGFR and ligand families such as VEGFR-1 and its ligand Placental Growth Factor (PlGF) can also contribute to developmental and pathological angiogenesis is less clear. We explored the function of PlGF in VEGF-A dependent angiogenesis using an in vitro co-culture assay in which endothelial cells are cultured on a fibroblast feeder layer. In the presence of 2% FS MCDB media (containing limited growth factors) in vitro endothelial tube formation is driven by endogenous angiogenic stimuli which are produced by the fibroblast and endothelial cells. Under these conditions independent sequestration of either free VEGF-A or PlGF with polyclonal and monoclonal antibodies inhibited tube formation suggesting that both ligands are required to drive an angiogenic response. Endothelial tube formation could only be driven within this assay by the addition of exogenous VEGF-A, VEGF-E or VEGF-A/PlGF heterodimer, but not by PlGF alone, implying that activation of either VEGFR-2/VEGFR-1 heterodimers or VEGFR-2 homodimers were responsible for eliciting an angiogenic response directly, but not VEGFR-1 homodimers. In contrast to results obtained with an endogenous angiogenic drive, sequestration of PlGF did not affect endothelial tube formation when the assay was driven by 1 ng/ml exogenous VEGF-A. These data suggest that although neutralising PlGF can be shown to reduce endothelial tube formation in vitro, this effect is only observed under restricted culture conditions and is influenced by VEGF-A. Such data questions whether neutralising PlGF would have a therapeutic benefit in vivo in the presence of pathological concentrations of VEGF-A. [ABSTRACT FROM AUTHOR]