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[Display omitted] • Novel triazole derivatives were designed and synthesized as VEGFR-2/telomerase inhibitors. • 7b showed the best average GI% (75.69 %) surpassing the average GI% of Dox (65.79 %). • 5d displayed the lowest IC 50 values at HNO-97 and FaDu. • 5a prompted telomerase downregulation by 0.60-fold, and 5b induced VEGFR-2 downregulation by 0.42-fold changes. • 5a upregulated caspases 3, 8, and 9, and downregulated CDK-2, 4, and 6. In this current work, we dedicated efforts to designing and synthesizing new 1,2,3-triazole-analogues (5a-d), (6a-d), and (7a-c) to act as dual VEGFR-2 and telomerase inhibitors with promising apoptotic potential. The synthesized analogues were examined against eleven diverse types of cancer cells and two normal cells to assess their ability to inhibit cell growth (GI%). Obviously, compound 7b showed the best average GI% (75.69 %) surpassing the average GI% of Dox (65.79 %). Compound 5d showed the lowest IC 50 values (25.86 and 51.91 µM) against HNO-97 and FaDu cancer cells, respectively. Besides, compound 5a exhibited the lowest IC 50 value (15.46 µM) against HCT 116 , whereas compound 6b revealed the lowest IC 50 value (31.14 µM) against HuH7. Besides, candidates 5a , 5b , 5d , and 7a showed prominent inhibitory results towards VEGFR-2 protein with decreasing its expression by 0.33, 0.42, 0.38 and 0.26-fold change, respectively. However, compounds 5a , 5b , 5d , and 7a showed promising inhibitory results towards telomerase protein and decreased its expression by 0.60, 0.50, 0.52, and 0.44-fold change, respectively. Additionally, it was clear that compound 5a was able to upregulate the expression of Caspases 3, 8, and 9 proteins by 2.19, 1.83, and 1.62-fold change, respectively. Besides, 5a was able to downregulate the expression of CDK-2, CDK-4, and CDK-6 proteins by 0.50, 0.43, and 0.13-fold change, respectively. Obviously, compound 5a halted the cell cycle at the G1, S, and G2-M phases in HCT 116 cells. Subsequently, the synthesized 1,2,3-triazole analogues can be treated as lead VEGFR-2 and telomerase inhibitors with potential apoptotic activity for future optimization and cancer treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel dual-target agent that binds to both VEGFR-2 and Tubulin was designed and synthesized. • Molecular docking towards VEGFR-2 and Tubulin was performed. • SAR is an indispensable component in the evaluation of new drug candidates. • Compound 19 significantly inhibited tumor growth on MGC-803 xenografts nude mice by intraperitoneal injection. Dual-target agents have more advantages than drug combinations for cancer treatment. Here, we designed and synthesized a series of novel VEGFR-2/tubulin dual-target inhibitors through a molecular hybridization strategy, and the activities of all the synthesized compounds were tested against tubulin and VEGFR-2. Among which, compound 19 exhibited strong potency against tubulin and VEGFR-2, with IC 50 values of 0.76 ± 0.11 μM and 15.33 ± 2.12 nM, respectively. Additionally, compound 19 not only had significant antiproliferative effects on a series of human cancer cell lines, especially MGC-803 cells (IC 50 = 0.005 ± 0.001 μM) but also overcame drug resistance in Taxol-resistant MGC-803 cells, with an RI of 1.8. Further studies showed that compound 19 could induce tumor cell apoptosis by reducing the mitochondrial membrane potential, increasing the level of ROS, facilitating the induction of G2/M phase arrest, and inhibiting the migration and invasion of tumor cells in a dose-dependent manner. In addition, compound 19 also exhibits potent antiangiogenic effects by blocking the VEGFR-2/PI3K/AKT pathway and inhibiting the tubule formation, invasion, and migration of HUVECs. More importantly, compound 19 demonstrated favorable pharmacokinetic profiles, robust in vivo antitumor efficacy, and satisfactory safety profiles. Overall, compound 19 can be used as a lead compound for the development of tubulin/VEGFR-2 dual-target inhibitors. [ABSTRACT FROM AUTHOR]

[Display omitted] • Novel inhibitors using fused thienopyrimidine scaffolds were evaluated as anti-proliferative agents against three cancer cell lines. • Two compounds 6 and 17 were the most promising candidates on the tested cancer cells with high selective toxicity-sparing normal cells. • Compound 6 inhibited VEGFR-2 and AKT-1 at IC 50 = 0.487 and 0.364 μM, respectively, while compound 17 showed IC 50 = 0.164 and 0.452 μM, respectively. • Compound 6 resulted in G1 phase cell cycle arrest while candidate 17 arrest cell cycle at G2/M phase. • Compound 17 showed the highest autophagic induction among the evaluated derivatives. • Docking studies were conducted to assess the binding patterns of the active derivatives inside the active sites of both VEGFR-2 and AKT-1 enzymes. Novel thieno[2,3- d ]pyrimidine analogues were designed, synthesized and evaluated for anti-proliferative activity against HepG-2, PC-3 and MCF-7 cancer cell lines. In addition, WI-38 normal cell line was used to explore the safety of all the tested compounds. Compounds 2 (IC 50 = 4.29 µM HePG-2 , 10.84 µM MCF-7), 6 (IC 50 = 14.86 μM HePG-2 , 8.04 μM PC-3 and 12.90 μM MCF-7) and 17 (IC 50 = 9.98 μM HePG-2 , 33.66 μM PC-3 and 14.62 μM MCF-7) were the most promising candidates on the tested cancer cells with high selective toxicity-sparing normal cells. A further mechanistic evaluation revealed promising kinase inhibitory activity, where compound 2 inhibited VEGFR-2 and AKT at IC 50 = 0.161 and 1.06 μM, respectively, Furthermore, derivative 6 inhibited VEGFR-2 and AKT at IC 50 = 0.487 and 0.364 μM, respectively, while compound 17 showed IC 50 = 0.164 and 0.452 μM, respectively. Moreover, compounds 2 , 6 resulted in G1 phase cell cycle arrest while candidate 17 arrest cell cycle at G2/M phase. Similar to the apoptosis results, compound 17 showed the highest autophagic induction among the evaluated derivatives. Finally, docking studies were conducted to assess the binding patterns of these active derivatives. The results showed that the binding patterns inside the active sites of both the VEGFR-2 and AKT-1 (allosteric pocket) crystal structures were identical to the reference ligands. [ABSTRACT FROM AUTHOR]

[Display omitted] • Tumor multidrug resistance is still the main cause of failure in the treatment of cervical cancer. • Overexpression of P-gp is a major factor in the development of multidrug resistance in cervical cancer. • Targeting the VEGF/VEGFR-2 signaling pathway is deemed as a promising therapeutic approach for cervical cancer treatment. • Chalcone matrices may have VEGFR-2 and P-gp inhibitor backbone potential. • Nitrogen-containing heterocycles are key pharmacophore for VEGFR-2 and P-gp inhibitors. Chemotherapy toxicity and tumor multidrug resistance remain the main reasons for clinical treatment failure in cervical cancer. In this study, 79 novel chalcone derivatives were designed and synthesized using the principle of active substructure splicing with the parent nucleus of licorice chalcone as the lead compound and VEGFR-2 and P-gp as the target of action and their potentials for anticervical cancer activity were preliminarily evaluated. The results showed that the IC 50 values of candidate compound B20 against HeLa and HeLa/DDP cells were 3.66 ± 0.10 and 4.35 ± 0.21 μΜ, respectively, with a resistance index (RI) of 1.18, which was significantly higher than that of the positive drug cisplatin (IC 50 :13.60 ± 1.63, 100.03 ± 7.94 μΜ, RI:7.36). In addition, B20 showed significant inhibitory activity against VEGFR-2 kinase and P-gp-mediated rhodamine 123 efflux, as well as the ability to inhibit the phosphorylation of VEGFR-2 and downstream PI3K/AKT signaling pathway proteins, inducing apoptosis, blocking cells in the S-phase, and inhibiting invasive migration and tubule generation by HUVEC cells. Acceptable safety was demonstrated in acute toxicity tests when B20 was at 200 mg/kg. In the nude mouse HeLa/DDP cell xenograft tumor model, the inhibition rate of transplanted tumors was 39.2 % and 79.2 % when B20 was at 10 and 20 mg/kg, respectively. These results suggest that B20 is a potent VEGFR-2 and P-gp inhibitor with active potential for treating cisplatin-resistant cervical cancer. [ABSTRACT FROM AUTHOR]

[Display omitted] • Synthesis of thiourea and thiocarbamate derivatives bearing sulfachloropyridazine. • Compounds were screened for cytotoxicity against a panel of 60 cell lines. • VEGFR-2 inhibitory activity was evaluated for promising compounds. • Apoptotic study and cell cycle effect were conducted for the most potent compound. • Radiosensitizer evaluation and docking study for the most potent compounds. In a search for new anticancer agents with better activity and selectivity, the present work described the synthesis of several new series of sulfachloropyridazine hybrids with thiocarbamates 3a-e , thioureids 4a-h , 5a-e and 4-substituted sulfachloropyridazines 6a, b , 7a, b and 8. The synthesized compounds were screened in vitro against a panel of 60 cancer cell lines in one dose assay. The most potent derivatives 3a, 3c, 4c, 4d, 5e, 7a and 7b were tested for their antiangiogenic activity by measuring their ability to inhibit VEGFR-2. The most potent compounds in VEGFR-2 inhibitory assay were further evaluated for their ability to inhibit PDGFR. In addition, the ability of 4c compound to inhibit cell migration on HUVEC cells and cell cycle effect on UO-31 cells has been studied. The pro-apoptotic effect of compound 4c was studied by the evaluation of caspase-3, Bax and BCl-2. Alternatively, the IC 50 of compounds 3a, 3c, 4c, 5e, 7a and 7b against certain human cancer cell lines were determined. Re-evaluation in combination with γ-radiation was carried out for compounds 4c , 5e and 7b to study the possible synergistic effect on cytotoxicity. Docking studies of the most active compounds were performed to give insights into the binding mode within VEGFR-2 active site. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel series of pyrazole derivatives 16a-l was designed and synthesized. • All the tested compounds 16a-l showed excellent COX-2 selectivity index. • Compounds 16a, 16c, 16d and 16 g were the most potent against NCI cancer cell lines. • Compounds 16a, 16c, 16d and 16 g showed excellent inhibition against VEGFR-2, EGFR. • Compounds 16a, 16c, 16d and 16 g could be promising anti-inflammatory and anti-cancer agents. A novel series of pyrazole derivatives with urea/thiourea scaffolds 16a-l as hybrid sorafenib/erlotinib/celecoxib analogs was designed, synthesized and tested for its VEGFR-2, EGFRWT, EGFRT790M tyrosine kinases and COX-2, pro-inflammatory cytokines TNF-α and IL-6 inhibitory activities. All the tested compounds showed excellent COX-2 selectivity index in range of 18.04–47.87 compared to celecoxib (S.I. = 26.17) and TNF-α and IL-6 inhibitory activities (IC 50 = 5.0–7.50, 6.23–8.93 respectively, compared to celecoxib IC 50 = 8.40 and 8.50, respectively). Screening was carried out against 60 human cancer cell lines by National Cancer Institute (NCI), compounds 16a, 16c, 16d and 16 g were the most potent inhibitors with GI% ranges of 100 %, 99.63–87.02 %, 98.98–43.10 % and 98.68–23.62 % respectively, and with GI 50 values of 1.76–15.50 µM, 1.60–5.38 µM, 1.68–7.39 µM and 1.81–11.0 µM respectively, in addition, of showing good safety profile against normal cell line (F180). Moreover, compounds 16a, 16c, 16d and 16 g had cell cycle arrest at G2/M phase with induced necrotic percentage compared to sorafenib of 2.06 %, 2.47 %, 1.57 %, 0.88 % and 1.83 % respectively. Amusingly, compounds 16a, 16c, 16d and 16 g inhibited VEGFR-2 with IC 50 of 25 nM, 52 nM, 324 nM and 110 nM respectively, compared to sorafenib (IC 50 = 85 nM), and had excellent EGFRWT and EGFRT790M kinase inhibitory activities (IC 50 = 94 nM, 128 nM, 160 nM, 297 nM), (10 nM, 25 nM, 36 nM and 48 nM) respectively, compared to both erlotinib and osimertinib (IC 50 = 114 nM, 56 nM) and (70 nM, 37 nM) respectively and showed (EGFRwt/EGFRT790M S.I.) of (range: 4.44–9.40) compared to erlotinib (2.03) and osmertinib (1.89). [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of novel thiophene-3-carboxamide derivatives as potential VEGFR-2 inhibitors was synthesized and evaluated for their antiproliferative activities. • The structure-activity relationship study of the target thiophene-3-carboxamide derivatives was summarized. • Compound 14d demonstrated significant inhibition of VEGFR-2 (IC 50 = 191.1 nM), and anti-proliferative activity in A549 cell line (IC 50 = 2.22 ± 0.19 μM). • The compound 14d could inhibit VEGFR-2 protein phosphorylation and could stably bind to the active site of VEGFR-2 in A549 cell line. • The compound 14d exhibited significant inhibitory effects on colony formation, migration, and tube formation in a dose-dependent manner. • The compound 14d could blocked the MEK-ERK signaling pathway in A549 cell lines, and could significantly suppressed the expression of MMP9 to prevent cell migration. VEGFR-2 is an attractive target for the development of anti-tumor drugs and plays a crucial role in tumor angiogenesis. This study reports a series of novel thiophene-3-carboxamide derivatives based on PAN-90806 as VEGFR-2 inhibitors, among which compound 14d exhibits excellent anti-proliferative activity against HCT116, MCF7, PC3, and A549 cell lines, and has effective VEGFR-2 inhibitory activity with an IC 50 value of 191.1 nM. Additionally, CETSA results indicated that VEGFR-2 was a relevant target of compound 14d in the cell lines, and compound 14d could also inhibit VEGFR-2 protein phosphorylation in A549 cell line. Furthermore, compound 14d inhibited colony formation, cell migration, and HUVECs tube formation in a dose-dependent manner. The mechanism by which 14d induced cancer cell death involves blocking the cell cycle, increasing ROS production, inducing apoptosis, and dose-dependently reducing the levels of phosphorylated ERK and MEK. Molecular docking and molecular dynamics simulations had shown that compound 14d could stably bind to the active site of VEGFR-2. These results confirmed that compound 14d might be a promising lead compound for anti-angiogenesis. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two series based 2-oxoindole derivatives. N -aryl acetamides 6a-o having amide linker and its isoster benzyloxy benzylidenes 9a-p were synthesized. • Compounds 6f & 9f were the most promising antiproliferative scaffolds in NCI one dose screening therefore they underwent five-dose testing. • Additionally, 6f & 9f were the most potent agents against pancreatic ductal adenocarcinoma MDA-PATC53 and PL45 cell lines with favorable safety profile when tested against normal prostate epithelial cells (RWPE-1). • Moreover, 6f & 9f displayed exceptional selectivity as a multiple kinase inhibitor, particularly targeting PDGFRα, PDGFRβ, and VEGFR-2 kinases with Nano molar concentrations. • Both 6f & 9f disrupt the G2/M cell cycle transition by upregulating p21 and reducing CDK1 and cyclin B1 mRNA levels. Two new series of N -aryl acetamides 6a-o and benzyloxy benzylidenes 9a-p based 2-oxoindole derivatives were designed as potent antiproliferative multiple kinase inhibitors. The results of one-dose NCI antiproliferative screening for compounds 6a-o and 9a-p elucidated that the most promising antiproliferative scaffolds were 6f and 9f , which underwent five-dose testing. Notably, the amido congener 6f was the most potent derivative towards pancreatic ductal adenocarcinoma MDA-PATC53 and PL45 cell lines (IC 50 = 1.73 µM and 2.40 µM, respectively), and the benzyloxy derivative 9f was the next potent one with IC 50 values of 2.85 µM and 2.96 µM, respectively. Both compounds 6f and 9f demonstrated a favorable safety profile when tested against normal prostate epithelial cells (RWPE-1). Additionally, compound 6f displayed exceptional selectivity as a multiple kinase inhibitor, particularly targeting PDGFRα, PDGFRβ, and VEGFR-2 kinases, with IC 50 values of 7.41 nM, 6.18 nM, and 7.49 nM, respectively. In contrast, the reference compound Sunitinib exhibited IC 50 values of 43.88 nM, 2.13 nM, and 78.46 nM against the same kinases. The derivative 9f followed closely, with IC 50 values of 9.9 nM, 6.62 nM, and 22.21 nM for the respective kinases. Both 6f and 9f disrupt the G2/M cell cycle transition by upregulating p21 and reducing CDK1 and cyclin B1 mRNA levels. The interplay between targeted kinases and these cell cycle regulators underpins the G2/M cell cycle arrest induced by our compounds. Also, compounds 6f and 9f fundamentally resulted in entering MDA-PATC53 cells into the early stage of apoptosis with good percentages compared to the positive control Sunitinib. The in silico molecular-docking outcomes of scaffolds 6a-o and 9a-p in VEGFR-2, PDGFRα, and PDGFRβ active sites depicted their ability to adopt essential binding interactions like the reference Sunitinib. Our designed analogs, specifically 6f and 9f , possess promising antiproliferative and kinase inhibitory properties, making them potential candidates for further therapeutic development. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • New thiazolylpyrazolyl coumarin derivatives were designed and synthesized. • Some compounds showed potent cytotoxic effect against MCF-7 and VEGFR-2 inhibition. • Compound 9d induced cell cycle arrest at G2/M phase and activated caspases-7 and 9. • Compound 9d up regulated p53 gene expression and elevated Bax/Bcl-2 ratio. • Molecular docking, dynamics simulation, QSAR and ADMET analysis were performed. Abstract New thiazolylpyrazolyl coumarin derivatives were synthesized and tested for their anticancer potential in vitro against five different human cell lines, including breast MCF-7, lung A549, prostate PC3, liver HepG2 and normal melanocyte HFB4. Breast carcinoma revealed higher sensitivity towards compounds 7a, 8c, 9b, 9c and 9d with IC 50 values ranging from 5.41 to 10.75 μM in comparison to the reference drug doxorubicin (IC 50 = 6.73 μM). In addition, no noticeable toxicity was exhibited towards normal cells HFB4. Moreover, in vitro studies of the VEGFR-2 inhibition in human breast cancer MCF-7 cell line for the promising cytotoxic compounds showed that compounds 7a, 8c, 9b, 9c and 9d were potent inhibitors at low micromolar concentrations (IC 50 = 0.034–0.582 μM) compared to the reference drug, sorafenib (IC 50 = 0.019 μM). Several theoretical and experimental studies were done to reveal the molecular mechanisms that control breast carcinoma metastasis. The mechanistic effectiveness in cell cycle progression, apoptotic induction and gene regulation were assessed for the promising compound 9d due to its remarkable cytotoxic activity against MCF-7 and significant VEGFR-2 inhibition. Flow cytometeric analysis showed that compound 9d induced cell growth cessation at G2/M phase and increased the percentage of cells at pre-G1 phase that stimulates the apoptotic death of MCF-7 cells. Furthermore, real time PCR assay illustrated that compound 9d up regulated p53 gene expression and elevated Bax/Bcl-2 ratio which confirmed the mechanistic pathway of compound 9d. Moreover, the apoptotic induction of breast cancer cells MCF-7 was enhanced effectively through activation of caspases-7 and 9 by compound 9d. On the other hand, a set of in silico methods such as molecular docking, molecular dynamics simulation, QSAR analysis as well as ADMET analysis was performed in order to study the protein-ligand interactions and the relationship between the physicochemical properties and the inhibitory activity of the promising compounds 7a , 8c and 9d. Based on the aforementioned findings, compound 9d could be considered as effective apoptosis modulator and promising lead for future development of new anti-breast cancer agents. [ABSTRACT FROM AUTHOR]

The vascular endothelial growth factors (VEGFs) and their cognate receptors (VEGFRs), besides their well-known involvement in physiological angiogenesis/lymphangiogenesis and in diseases associated to pathological vessel formation, play multifaceted functions in the central nervous system (CNS). In addition to shaping brain development, by controlling cerebral vasculogenesis and regulating neurogenesis as well as astrocyte differentiation, the VEGFs/VEGFRs axis exerts essential functions in the adult brain both in physiological and pathological contexts. In this article, after describing the physiological VEGFs/VEGFRs functions in the CNS, we focus on the VEGFs/VEGFRs involvement in neurodegenerative diseases by reviewing the current literature on the rather complex VEGFs/VEGFRs contribution to the pathogenic mechanisms of Alzheimer's (AD) and Parkinson's (PD) diseases. Thereafter, based on the outcome of VEGFs/VEGFRs targeting in animal models of AD and PD, we discuss the factual relevance of pharmacological VEGFs/VEGFRs modulation as a novel and potential disease-modifying approach for these neurodegenerative pathologies. Specific VEGFRs targeting, aimed at selective VEGFR-1 inhibition, while preserving VEGFR-2 signal transduction, appears as a promising strategy to hit the molecular mechanisms underlying AD pathology. Moreover, therapeutic VEGFs-based approaches can be proposed for PD treatment, with the aim of fine-tuning their brain levels to amplify neurotrophic/neuroprotective effects while limiting an excessive impact on vascular permeability. [Display omitted] ● The VEGFs/VEGFRs system plays an essential role in brain development and functions. ● VEGFs/VEGFRs alterations contribute to Alzheimer's (AD) and Parkinson's (PD) diseases. ● Selective VEGFR-1 inhibition, preserving VEGFR-2 neuroprotective function, may be beneficial for AD. ● Fine-tuning VEGF-A brain levels and VEGF-B/-C administration are proposed for PD treatment. [ABSTRACT FROM AUTHOR]

[Display omitted] • Triazole-quinoxaline hybrids were crafted as dual VEGFR-2 /MAO-B inhibitors for halting CRC. • 11 and 14 surpassed 5-FU against HCT-116 cells regarding potency and selectivity. • 14 recorded one-digit nanomolar IC 50 concentration against VEGFR-2. • 11 was superior to the reference MAOI methylene blue with MAO-B/A selectivity. • 11 and 14 downregulated HIF-1α in HCT-116 cells and inhibited their migration by >75 %. Monoamine oxidases (MAOs) and vascular endothelial growth factor receptor-2 (VEGFR-2) are promoters of colorectal cancer (CRC) and central signaling nodes in epithelial-mesenchymal transition (EMT) induced by activating hypoxia-inducible factors (HIFs). Herein, a novel series of rationally designed triazole-tethered quinoxalines were synthesized and evaluated against HCT-116 CRC cells. The tailored scaffolds combine the pharmacophoric themes of both VEGFR-2 inhibitors and MAO inhibitors. All the synthesized derivatives were screened utilizing the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2 H -tetrazolium bromide (MTT) assay for their possible cytotoxic effects on normal human colonocytes, then evaluated for their anticancer activities against HCT-116 cells overexpressing MAOs. The hit derivatives 11 and 14 exhibited IC 50 = 18.04 and 7.850 µM, respectively, against HCT-116 cells within their EC 100 doses on normal human colonocytes. Wound healing assay revealed their efficient CRC antimetastatic activities recording HCT-116 cell migration inhibition exceeding 75 %. In vitro enzymatic assays demonstrated that both 11 and 14 efficiently inhibited VEGFR-2 (IC 50 = 88.79 and 9.910 nM), MAO-A (IC 50 = 0.763 and 629.1 nM) and MAO-B (IC 50 = 0.488 and 209.6 nM) with observed MAO-B over MAO-A selectivity (SI = 1.546 and 3.001), respectively. Enzyme kinetics studies were performed for both compounds to identify their mode of MAO-B inhibition. Furthermore, qRT-PCR analysis showed that the hits efficiently downregulated HIF-1α in HCT-116 cells by 3.420 and 16.96 folds relative to untreated cells. Docking studies simulated their possible binding modes within the active sites of VEGFR-2 and MAO-B to highlight their essential structural determinants of activities. Finally, they recorded in silico drug-like absorption, distribution, metabolism, excretion, and toxicity (ADMET) profiles as well as ligand efficiency metrics. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • 25 compounds were screened against VEGFR-2 kinase enzyme. • Selected compounds were assessed in vitro against full NCI 60 cell lines. • 10a showed the best in vitro antitumor activity against human breast cancer (T7-47D) and renal cancer (A498) cell lines. • Cell cycle and caspase-3 colorimetric assays were performed. • Molecular Modeling studies have been carried out. Abstract Different series of novel thieno [2,3- d ]pyrimidine derivative (9a-d , 10a-f,l,m and 15a-m) were designed, synthesized and evaluated for their ability to in vitro inhibit VEGFR-2 enzyme. Also, the cytotoxicity of the final compounds was tested against a panel of 60 different human cancer cell lines by NCI. The VEGFR-2 enzyme inhibitory results revealed that compounds 10d , 15d and 15 g are among the most active inhibitors with IC 50 values of 2.5, 5.48 and 2.27 µM respectively, while compound 10a remarkably showed the highest cell growth inhibition with mean growth inhibition (GI) percent of 31.57%. It exhibited broad spectrum anti-proliferative activity against several NCI cell lines specifically on human breast cancer (T7-47D) and renal cancer (A498) cell lines of 85.5% and 77.65% inhibition respectively. To investigate the mechanistic aspects underlying the activity, further biological studies like flow cytometry cell cycle together with caspase-3 colorimetric assays were carried on compound 10a. Flow cytometric analysis on both MCV-7 and PC-3 cancer cells revealed that it induced cell-cycle arrest in the G0-G1phase and reinforced apoptosis via activation of caspase-3. Furthermore, molecular modeling studies have been carried out to gain further understanding of the binding mode in the active site of VEGFR-2 enzyme and predict pharmacokinetic properties of all the synthesized inhibitors. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Two series of indazole-based derivatives were synthesized. • Compds 11b , 11c , and 11e had VEGFR-2 IC 50 = 5.4 nM, 5.6 nM, and7 nM, respectively. • Compds 11a and 11c showed the most potent anticancer activity. • Molecular dynamics simulation was utilized to study their binding mode. Abstract VEGFR-2 has a pivotal role in promoting cancer angiogenesis. Herein, two series of novel indazole-based derivatives were designed, synthesized and evaluated for their in vitro inhibitory action against VEGFR-2 kinase enzyme. The second series 11a-e exhibited better potency than the first one 7a-d and 8a-f. Compounds 11b , 11c and 11e exhibited the most potent action, with IC 50 of 5.4 nM, 5.6 nM and 7 nM, respectively. As a measure of cellular VEGFR-2 inhibition, compounds 11b and 11c showed strong inhibition of human umbilical vein endothelial cells (HUVEC) proliferation with 80% and 99.6% inhibition at 10 μM concentration, respectively. Attempting to interpret SAR of the synthesized compounds, and provide a basis for further optimization; a comprehensive modeling study was implemented. Molecular docking, dynamics simulation and free energy calculation of the synthesized compounds along with known VEGFR-2 inhibitors were applied. The study illustrated the effect of several factors on VEGFR-2 inhibition, such as the interaction with solvent accessible region of the enzyme, the presence of NH linker and the degree of conformational restriction. Finally, our compounds were evaluated for their in vitro anti-proliferative effect against the full NCI panel of cancer cell lines, where compounds 11a and 11c displayed mean GI% of 93 and 130%, respectively, and showed partly a better behavior than the FDA approved drug sorafenib, with respect to activity (GI 50) and safety (LC 50) against several cell lines. Thus, compound 11c represents a promising candidate for cancer treatment through antiangiogenic dependent and antiangiogenic independent modes of action. [ABSTRACT FROM AUTHOR]

[Display omitted] • Cytotoxicity of seventeen new quinoxaline derivatives was evaluated against MCF-7 and HCT-116 by MTT assay. • VEGFR2 kinase inhibitory activity and anti-angiogenic potential were evaluated for the most active hits. • Apoptosis studies and cell cycle analysis were evaluated for the most active derivative. • Docking of the most active compound in the active site of VEGFR2 kinase enzyme was done. • In silico assessment of all the library was performed. Vascular endothelial growth factor receptor-2 is a dynamic target for therapeutic intervention in various types of cancer. This study was aimed at exploring the VEGFR-2 inhibitory activity of a novel library of quinoxalin-2-one derivatives such as 3-furoquinoxaline carboxamides, 3-pyrazolylquinoxalines, and 3-pyridopyrimidyl-quinoxalines. Among them, 6c, 7a, and 7d-f produced remarkable cytotoxicity against HCT-116 (IC 50 ′s 4.28–9.31 µM) and MCF-7 (IC 50 ′s 3.57–7.57 µM) cell lines using the MTT assay and doxorubicin (DOX) as a reference standard. Interestingly, results of cytotoxicity towards the human fibroblast cell line WI38 revealed that these hits demonstrated higher selectivity indices towards both HCT-116 (SI 8.69–23.19) and MCF-7 (SI 9.48–27.80) than DOX, SI 0.72 and 0.90, respectively. Then, these hits were subjected to a mechanistic study; they showed direct inhibition of VEGFR-2. Impressively, compound 7f displayed 1.2 times the VEGFR-2 inhibitory activity of sorafenib. The antiangiogenic potential of 7f was proved via lowering the level of VEGF-A, than that of control. It as well, exhibited scratch closure percent of 61.8%, compared with 74.5% of control at 48 hrs, indicating the potential anti-migratory effect of the compound 7f. It significantly increased the expression of tumor suppressor gene (p53) on MCF-7 cells by almost 18 folds and upregulated the caspase-3 level by 10.7 folds, compared to the control. Cell cycle analysis revealed cell cycle arrest at G2/M together with a PreG increase which indicated apoptosis induction potential. Annexin V-FITC apoptosis results proposed the two modes of cell death (apoptosis and necrosis) as an inherent mechanism of cytotoxicity of compound 7f. Molecular docking further supported the mechanism showing the affinity of target compounds for VEGFR-2 active site. Moreover, physicochemical and drug-like properties were assessed from the ADME properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • VEGFs proof angiogenic and antiapoptotic effects via paracrine and autocrine loops. • Phenylpyridazinone based VEGFR-2 inhibitors were optimized from sorafenib. • Compounds 12c and 13a showed excellent antiproliferative effect against HUVECs. • Compounds 12c and 13a revealed increase in apoptosis and necrosis percentages. • Compounds 12c and 13a distinctly inhibit cells in invasion and migration assays. Appertaining to its paracrine and autocrine signaling loops, VEGFR-2 succeeded in grabbing attention as one of the leading targets in cancer treatment. Based on the foregoing and our comprehensive studies regarding pharmacophoric features and activity of sorafenib, novel phenylpyridazinone based VEGFR-2 inhibitors 4 , 6a-e , 7a,b , 9a,b , 12a-c , 13a,b , 14a,b , 15a,b , and 17a-d were optimized. An assortment of biological assays was conducted to assess the antiangiogenic and apoptotic activities of the synthesized derivatives. In vitro VEGFR-2 kinase assay verified the inhibitory activity of the synthesized derivatives with IC 50 values from 49.1 to 418.0 nM relative to the reference drug sorafenib (IC 50 = 81.8 nM). Antiproliferative activity against HUVECs revealed that compounds 2-{2-[2-(6-oxo-3-phenylpyridazin-1(6H)-yl)acetyl]hydrazineyl}- N -(p-tolyl)acetamide (12c) and 2-[(5-mercapto-4-methyl- 4H -1,2,4-triazol-3-yl)methyl]-6-phenylpyridazin-3(2H)-one (13a) possessed superior activity (IC 50 values = 11.5 and 12.3 nM, respectively) in comparison to sorafenib (IC 50 = 23.2 nM). For the purpose of appraising their antiproliferative effect, derivatives 12c and 13a were exposed to cell cycle analysis, apoptotic, cell invasion and migration assays in addition to determination of VEGFR-2 in protein level. Moreover, cytotoxicity as well as selectivity index against WI-38 cell line was measured to examine safety of derivatives 12c and 13a. After that, molecular docking study was executed on the top five compounds in the in vitro VEGFR-2 kinase assay 6d , 12c , 13a , 14a and 17c to get a deep perception on binding mode of the synthesized compounds and correlate the design strategy with biological results. Finally, physicochemical, pharmacokinetic properties, and drug-likeness studies were performed on the top five derivative in in vitro VEGFR-2 kinase assay. [ABSTRACT FROM AUTHOR]

The clinical manifestations of pterygium are characterized by rapid growth and postoperative recurrences. We had previously proposed that hypoxia-inducible factor (HIF)-1α recruits progenitor cells during the development and progression of pterygia. Recently, it was reported that various stimuli, including inflammation, could activate HIF-1α even under normoxic conditions. The ocular surface directly faces external environments, and is thus frequently exposed to inflammatory insults. First, we examined the gene expression of HIF-1α, its downstream molecule, vascular endothelial growth factor (VEGF)-A, and VEGF receptor (VEGFR)-2 in corneal and conjunctival cells compared with cultured human umbilical vein endothelial cells. Corneal fibroblasts had high expression of VEGFR-2 in the presence of TNF-α, and HIF-1α was activated by TNF-α in diverse ocular surface cells. The HIF-1α/VEGF/VEGFR signaling pathway in response to TNF-α was evaluated in cultured human pterygium fibroblasts (HPFs) at the gene and protein levels and was compared to treatment with cobalt chloride (CoCl 2 ), a hypoxic mimetic, to exclude the effect of hypoxia. Although VEGF-A expression was not changed by TNF-α, expression of HIF-1α and VEGFR-2 was enhanced in HPFs treated with TNF-α, independent of hypoxia conditioning. In addition, VEGF-C gene expression was activated solely by TNF-α in HPF, but VEGF-B levels were not significantly affected. These results may provide mechanistic explanations for the uniquely vigorous proliferation of pterygium fibrovascular tissue during TNF-α-induced ocular surface inflammation. [ABSTRACT FROM AUTHOR]

In our efforts to develop novel dual c-Met/VEGFR-2 inhibitors as potential anticancer agents, a series of 2-substituted-4-(2-fluorophenoxy) pyridine derivatives bearing pyrazolone scaffold were designed and synthesized. The cell proliferation assay in vitro demonstrated that most target compounds had inhibition potency on both c-Met and VEGFR-2, especially compound 9h , 12b and 12d . Based on the further enzyme assay in vitro , compound 12d was considered as the most promising one, the IC 50 values of which were 0.11 μM and 0.19 μM for c-Met and VEGFR-2, respectively. Further molecular docking studies suggested a common mode of interaction at the ATP-binding site of c-Met and VEGFR-2, indicating that 12d was a potential compound for cancer therapy deserving further study. [ABSTRACT FROM AUTHOR]

[Display omitted] • VEGFR-2 is aberrantly expressed in many malignant tumors. • Developments or discoveries of VEGFR-2-based inhibitors with multi-targeting capabilities were summarized. • The rational design and SARs of multi-targeting agents were discussed. • The therapeutic effects might be improved by simultaneously inhibiting VEGFR-2 and other targets. Vascular epidermal growth factor receptor-2 (VEGFR-2), as an important tyrosine transmembrane protein, plays an important role in regulating endothelial cell proliferation and migration, regulating angiogenesis and other biological functions. VEGFR-2 is aberrantly expressed in many malignant tumors, and it is also related to the occurrence, development, and growth of tumors and drug resistance. Currently, there are nine VEGFR-2 targeted inhibitors approved by US.FDA for clinical use as anticancer drugs. Due to the limited clinical efficacy and potential toxicity of VEGFR inhibitors, it is necessary to develop new strategies to improve the clinical efficacy of VEGFR inhibitors. The development of multitarget therapy, especially dual-target therapy, has become a hot research field of cancer therapy, which may provide an effective strategy with higher therapeutic efficacy, pharmacokinetic advantages and low toxicity. Many groups have reported that the therapeutic effects could be improved by simultaneously inhibiting VEGFR-2 and other targets, such as EGFR, c-Met, BRAF, HDAC, etc. Therefore, VEGFR-2 inhibitors with multi-targeting capabilities have been considered to be promising and effective anticancer agents for cancer therapy. In this work, we reviewed the structure and biological functions of VEGFR-2, and summarized the drug discovery strategies, and inhibitory activities of VEGFR-2 inhibitors with multi-targeting capabilities reported in recent years. This work might provide the reference for the development of VEGFR-2 inhibitors with multi-targeting capabilities as novel anticancer agents. [ABSTRACT FROM AUTHOR]

Vascular endothelial growth factor (VEGF) secreted by the retinal pigment epithelium (RPE) plays an important role in ocular homeostasis, but also in diseases, most notably age-related macular degeneration (AMD). To date, anti-VEGF drugs like ranibizumab have been shown to be most effective in treating these pathologic conditions. However, clinical trials suggest that the RPE could degenerate and perish through anti-VEGF treatment. Herein, we evaluated possible pathways and outcomes of the interaction between ranibizumab and human RPE cells (ARPE-19). Results indicate that ranibizumab affects the VEGF-A metabolism in RPE cells from an extra- as well as intracellular site. The drug is taken up into the cells, with the VEGF receptor 2 (VEGFR-2) being involved, and decreases VEGF-A protein levels within the cells as well as extracellularly. Oxidative stress plays a key role in various inflammatory disorders of the eye. Our results suggest that oxidative stress inhibits RPE cell proliferation. This anti-proliferative effect on RPE cells is significantly enhanced through ranibizumab, which does not inhibit RPE cell proliferation substantially in absence of relevant oxidative stress. Therefore, we emphasize that anti-VEGF treatment should be selected carefully in AMD patients with preexistent extensive RPE atrophy. [ABSTRACT FROM AUTHOR]

In an effort to develop ATP-competitive VEGFR-2 selective inhibitors, a novel series of tricyclic pyrido[3′,2′:4,5]thieno[3,2- d ]pyrimidin-4-amine derivatives were designed and synthesized. These compounds were characterized by IR, 1 H NMR, 13 C NMR, elemental and mass spectral analyses. Docking studies have given a partial insight into the molecular determinants of the activity of this novel series in VEGFR-2 kinase active site. Moreover, these compounds were assessed at 10 μM for their selective inhibitory activities over a panel of 6 human kinases, namely VEGFR-1/Flt-1, VEGFR-2/KDR, EGFR, CDK5/p25, GSK3α and GSK3β. Compound N -(4,6-dimethylthieno[2,3- b ]pyridine)-7,9-dimethylpyrido[3′,2′:4,5]thieno[3,2- d ]pyrimidin-4-amine (9d) exhibited the most potent and selective inhibitory activity against VEGFR-2/KDR over the six human kinases, with an IC 50 value 2.6 μM. The identification of this hit candidate could aid the design of new tricyclic-based VEGFR-2 kinase modulators. [ABSTRACT FROM AUTHOR]

[Display omitted] • The synthesis of new 6-bromo-2-(pyridin-3-yl)-4-substituted quinazolines. • Seventeen of the target compounds were evaluated as dual EGFR/HER2 inhibitors compared to lapatinib and fourteen compounds were tested as VEGFR-2 inhibitors. • The most active compounds were screened for their cytotoxicity. • Compounds 9d , 11c and 14c were subjected to cell cycle analysis and apoptotic assay. • A molecular modeling study was achieved. The present study involves design and synthesis of five series of 6-bromo-2-(pyridin-3-yl)-4-substituted quinazolines 9a-l , 11a-e , 13a-c , 14a-f and 15a-e. Candidates 9a-l and 11a-e were evaluated for their EGFR and HER2 inhibitory activity compared to Lapatinib. Compounds 9b , 9d , 9f , 11b and 11c were further screened for their in vitro cytotoxicity against two human breast cancer cell lines: AU-565 and MDA-MB-231 in addition to normal breast cell line MCF10A. Compound 9d revealed a remarkable cytotoxic efficacy against AU-565 cell line (IC 50 = 1.54 µM) relative to Lapatinib (IC 50 = 0.48 µM), whereas compounds 9d and 11c showed a superior cytotoxicity towards MDA-MB-231 (IC 50 = 2.67 and 1.75 µM, respectively) in comparison to Lapatinib (IC 50 = 9.29 µM). Moreover, compounds 13a-c , 13a-c , 14a-f and 15a-e were tested for their VEGFR-2 inhibitory activity compared to Sorafenib. Compounds 13a , 14c and 14e exhibited remarkable inhibition (IC 50 = 79.80, 50.22 and 78.02 nM, respectively) relative to Sorafenib (IC 50 = 51.87 nM). In vitro cytotoxicity of these compounds against HepG2, HCT-116 and normal cell (WISH) revealed a superior cytotoxicity against HepG2, HCT-116 especially 13a (IC 50 = 17.51 and 5.56 µM, respectively) and 14c (IC 50 = 10.40 and 3.37 µM, respectively) compared to Sorafenib (IC 50 = 19.33 and 6.82 µM, respectively). Compounds 9d , 11c and 14c were subjected to cell cycle analysis and apoptotic assay. Molecular docking and ADME prediction studies were fulfilled to illustrate the interaction of the potent derivatives with the hot spots of the active site of EGFR, HER2 and VEGFR-2 along with prediction of their pharmacokinetic and physicochemical properties. [ABSTRACT FROM AUTHOR]

[Display omitted] • New thiophene, thienopyridine, and thiazoline-based derivatives 5a-c , 7, 9, 12a,b, and 14a,b were designed and synthesized. • The cytotoxic activity of the new compounds was evaluated in vitro against the liver (HepG-2), breast (MCF-7), colon (HCT-116), and WI-38 cell lines. • The most promising cytotoxic agents 5a-c were examined as multitargeting inhibitors against Pim, VEGFR, and EGFRWT. • The impact of compound 5c was evaluated on the cell cycle, apoptosis, and the proapoptotic parameters Bax/Bcl-2 ratio, p53, and caspase-3. • Antimicrobial assay of all compounds was carried against different types of pathogenic gram-positive, gram-negative bacteria and fungi. • Molecular docking results of compounds 5a proved its promising binding interactions with Pim, VEGFR, and EGFRWT. In silico ADMET studies were carried out to explore the drug-likeness properties of the new compounds. Multitargeting kinase inhibitors recently proved to be a profitable approach for conquering cancer proliferation. The current study represents the design and synthesis of new thiophene, thienopyridine, and thiazoline-based derivatives 4-14a,b. All the target compounds were examined in vitro against three cancer cell lines; the liver (HepG-2), breast (MCF-7), and colon (HCT-116) where the thiophene-based compounds 5a-c , demonstrated the most potent activity. Furthermore, the latter derivatives revealed a safety profile against WI-38 normal cell line of selectivity indices ranging from 4.43 to 17.44. In vitro enzyme assay of 5a-c revealed that the carbohydrazide analog 5c has the most promising multitargeting inhibiting activity against Pim-1, VEGFR-2, and EGFRWT enzymes of IC 50 values; 0.037 ± 0.02, 0.95 ± 0.24, and 0.16 ± 0.05 µM, respectively. As it was the most potent analog, 5c was further subjected to cell cycle and apoptosis analysis. The results indicated that it induced preG1 arrest and an apoptotic effect in the early and late stages. Moreover, further apoptosis studies were carried out for 5c to evaluate its proapoptotic potential. Interestingly, 5c enhanced the levels of Bax/Bcl-2 ratio, p53, and active caspase 3 by 18, 6.4, and 24 folds, respectively compared to the untreated cells. The antimicrobial evaluation showed that only compounds 3 and 5a produced broad-spectrum potency, while 5b and 5c exhibited outstanding antifungal effects. Finally, a molecular docking study was carried out to discover the probable interactions of compound 5c with the active sites of Pim-1, VEGFR-2, and EGFRWT kinases. [ABSTRACT FROM AUTHOR]

[Display omitted] • Twelve 1,2,3-triazoles bearing semicarbazone and thiosemicarbazone fragments were designed and synthesized. • Their cytotoxicity was evaluated against sixty human cancer cell lines. • Myeloid leukemia cancer cells were the most sensitive toward their effect. • Compounds 21, 26, and 30 exerted the most potent cytotoxic activity. • Compound 30 further evaluated for its apoptosis induction and VEGFR-2 inhibition potential. Vascular Endothelial Growth Factor II (VEGFR-2) has been proved as a rational target in cancer therapy. Although currently prescribed VEGFR-2 inhibitors are showing potent antitumor activity, they are often causing serious unwanted effects, restricting their extensive use as chemotherapeutics. Herein, after analyzing the structures of the effective VEGFR-2 inhibitor molecules, we report the synthesis of a new set of semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles with expected potency of inhibiting the VEGFR-2 signaling. The design of new compounds considered maintaining the essential pharmacophoric features of sorafenib for effective binding with the receptor target. All compounds have been evaluated for their growth inhibition effect against a panel of sixty cancer cells at the National Cancer Institute. Leukemia cancer cells, especially HL-60 and SR, were shown to be the most sensitive to the cytotoxic effect of new compounds. Thiosemicarbazones 21 , 26 , and 30 exhibited the best activity against almost all tested cancer cells. Therefore, a set of subsequent in vitro biological evaluations has been performed to understand the mechanistic effect of these compounds further. They inhibited the VEGFR-2 with IC 50 values of 0.128, 0.413, and 0.067 µM respectively compared with 0.048 µM of Sorafenib. The probable mechanistic effect of 30 has been further evaluated on a number of apoptotic and antiapoptotic markers including BAX, BCL2, caspase-3, and caspase-9. Results revealed the potential of the thiosemicarbazone-linked triazole 30 to induce both the early and the late apoptosis, elevate BAX/BCL2 ratio, induce caspase-3 & caspase-9, and arrest the HL-60 cell cycle at the G2/M and G0-G1 phases. Molecular docking of new semicarbazones and thiosemicarbazones into the proposed biological target receptor has also been performed. Results of docking studies proved the potential of new semicarbazone- and thiosemicarbazone-linked 1,2,3-triazoles to effectively bind with crucial residues of the VEGFR-2 binding pocket. [ABSTRACT FROM AUTHOR]

In an effort to develop ATP-competitive VEGFR-2 selective inhibitors, a series of new quinoxaline-based derivatives was designed and synthesized. The target compounds were biologically evaluated for their inhibitory activity against VEGFR-2. The design of the target compounds was accomplished after a profound study of the structure activity relationship (SAR) of type-II VEGFR-2 inhibitors. Among the synthesized compounds, 1-(2-((4-methoxyphenyl)amino)-3-oxo-3,4 dihydroquinoxalin-6-yl)-3-phenylurea ( VIIa ) displayed the highest inhibitory activity against VEGFR-2. Molecular modeling study involving molecular docking and field alignment was implemented to interpret the variable inhibitory activity of the newly synthesized compounds. [ABSTRACT FROM AUTHOR]

[Display omitted] • A series of novel thieno[2,3- d ]pyrimidine derivatives 3, 4a-d, 5a-c, 7a,b and 9a,b were designed as anticancer agents. • The anticancer activity of compounds was determined by the NCI (USA) as one dose and five doses on 60 cell lines. • IC 50 values of compounds 4a and 4b were determined against VEGFR-2 and BRAFV600E and BRAFWT protein kinases. • 4a and 4b treated breast MCF7 cell line showed down-regulation of total VEGFR-2 and phosphorylated VEGFR-2. • 4a and 4b induced apoptosis in MCF7 cell line and increased the level of caspase-9 apoptotic marker. A series of novel thieno[2,3- d ]pyrimidine derivatives was designed and synthesized based on multitarget directed drug design strategy. All the newly synthesized compounds were evaluated for their antiproliferative activity in the National Cancer Institute (NCI) against a panel of 60 tumor cell lines. Compounds 4a and 4b showed a significant antiproliferative activity at 10 µM dose, and were accordingly evaluated at five dose concentrations. They showed potent and broad-spectrum antiproliferative activity, with GI 50 values in the micromolar range of 1.44–6.93 µM and 1.66–5.82 µM, respectively. They also showed TGI values in the cytostatic range of 3.49–97.3 µM and 3.33–77.3 µM respectively. These two compounds potently inhibited VEGFR-2 with IC 50 = 0.111 ± 0.006 and 0.049 ± 0.003 µM, BRAFV600E with IC 50 = 0.089 ± 0.005 and 0.063 ± 0.003 µM and BRAFWT IC 50 = 0.071 ± 0.004 and 0.05 ± 0.003 µM, respectively in comparison to sorafenib IC 50 values of 0.031 ± 0.002, 0.035 ± 0.002 and 0.021 ± 0.001 µM against VEGFR-2, BRAFV600E and BRAFWT, respectively. Compounds 4a and 4b showed also potent down-regulation of total VEGFR-2 and phosphorylated VEGFR-2. In addition, the HUVECs migratory potential was greatly reduced resulting in significantly disrupted wound healing patterns after treatment with compounds 4a and 4b for 72 h. Furthermore, Compounds 4a and 4b induced apoptosis by 22.82- and 25.81-fold increase in the total apoptosis percentage in breast cancer MCF7 cell line. This apoptotic activity was supported by an increase in the level of apoptotic caspase-9 by 6.17- and 9.07-fold, respectively. Moreover, the cell cycle analysis showed that compounds 4a and 4b arrested the cell cycle mainly in the G1 and G1/S phases, respectively. The molecular modeling studies were performed to assess the binding pattern and affinity of derivatives 4a and 4b toward the VEGFR-2 and BRAF active sites. [ABSTRACT FROM AUTHOR]

[Display omitted] • Simultaneous inhibition of MMP-2, CA II and VEGFR-2 via triazoles bearing sulfonamide appendages. • 8d and 8e were nanomolar MMP-2/VEGFR-2 inhibitors and sub-micromolar inhibitors of CA II. • They upregulated p53 up to 3 folds, induced HepG-2 cells apoptosis and were superior to doxorubicin. • Docking studies predicted the structural determinants of activity. • They displayed drug-like in silico ADMET properties and ligand efficiency metrics. Recently, the interest in targeting metalloenzymes is obviously growing for halting various tumor progression events and surmounting the resistance due to routine chemotherapy regimen. In this regard, attention to MMP-2 and CA II has been drawn as validated druggable anticancer targets that share vital signaling pathways. The vast majority of MMP and CA inhibitors are designed to function as directed single-target agents. In spite of their transient efficacy, they are often susceptible to tumor resistance. Hence, several dual inhibitors of correlated MMPs and CAs were introduced. This set the stage to simultaneously target the common vital signaling nodes as well. VEGFR-2 is considered central to various tumorigenesis processes involving both MMP-2 and CA II. Herein, we report concomitant inhibition of MMP-2, CA II, and VEGFR-2 via rationally designed 1,2,3- and 1,2,4-triazole hybrids bearing various sulfonamide appendages following pharmacophore hybridization strategy. The designed adducts were efficiently elaborated in an almost quantitative yield utilizing microwave-assisted click 1,3-dipolar cycloaddition reaction between various alkynes-based 1,2,4-triazole and 4-azido benzensulfonamides. All derivatives were evaluated for their anticancer potential against three human cancer cell lines (Caco-2, MDA-MB-231, and HepG-2) after safety assessment on normal human cells (Wi-38). Amongst those click adducts, 8d and 8e were the most potent and safest anticancer agents exhibiting low range nanomolar IC 50 (7.37–11.96 nM) and high selectivity (SI = 3.01–4.46), against the studied cancer cell lines, hence superior to doxorubicin concerning potency (IC 50 = 10.63–48.25 nM) and selectivity (SI = 0.43–1.93). They significantly elevated the expression level of the tumor suppressor p53 in the three tested cancer cell lines up to 3 folds and induced apoptosis in HepG-2 cells with higher potential to 8d over 8e. Enzymatic evaluation showed that both derivatives were potent dual MMP-2/VEGFR-2 inhibitors, particularly 8d (MMP-2; IC 50 = 5.66 nM and VEGFR-2; IC 50 = 6.65 nM), relative to the reference MMP-2 inhibitor NNGH (IC 50 = 299.50 nM) and VEGFR-2 inhibitor sorafenib (IC 50 = 4.92 nM). Both 8d and 8e exhibited relatively moderate activity against the human CA II isoform (IC 50 = 116.9 and 187.5 nM, respectively) relative to the reference (IC 50 = 27.3 nM). Docking studies clearly explained the superior in vitro enzymatic inhibition profiles of 8d over 8e and predicted the structural determinants of activity. Nevertheless, 8d displayed promising in silico ADMET properties and ligand efficiency metrics. These findings evidently demonstrated the sulfatriazole 8d as an auspicious multi-target-directed ligand that deserves further optimization for developing novel antitumor agents. [ABSTRACT FROM AUTHOR]

Highlights: [•] We discovered a new member of VEGFxxxb family-VEGF111b. [•] We found VEGF111b mRNA and protein can be induced by mitomycin C. [•] We confirmed VEGF111b over-expression inhibits angiogenesis. [•] VEGF111b inhibits angiogenesis through inhibiting VEGF-R2/PI3K/Akt and VEGF-R2/ERK1/2 phosphorylation. [ABSTRACT FROM AUTHOR]

Abstract: Objective: Ovarian cancer is the most lethal of all gynecologic malignancies. It is characterized by the spread of intraperitoneal tumors, accumulation of ascites, and formation of tumor blood vessels. Cyclin I has been linked with angiogenesis-related proteins, like vascular endothelial growth factor (VEGF) and VEGF receptor 2 (VEGFR-2), in human breast cancer. We examined whether an association exists between expression of cyclin I, VEGFR-2, clinicopathologic parameters and survival of patients with epithelial ovarian cancer (EOC). Methods: Cyclin I and VEGFR-2 expressions were analyzed by immunohistochemistry in 55 human primary EOC tissue specimens. Results: Cyclin I immunoreactivity was significantly correlated with VEGFR-2 (R=0.4587, P=0.0004), and immunolabeling of cyclin I and VEGFR-2 significantly correlated with cancer cells'' proliferative activity evaluated using cyclin A labeling index as a marker (R=0.3107, P=0.0209 and R=0.4183, P=0.0015, respectively). VEGFR-2 immunostaining was significantly higher in advanced, poorly differentiated, and suboptimally resected EOCs compared to their counterparts (P<0.05). Finally, higher VEGFR-2 expression was significantly associated with shorter disease-free survival (P=0.0437). Conclusions: Our results indicate that elevated expression of cyclin I and VEGFR-2 is likely to provide a proliferative advantage to the EOC cells, and that cyclin I may be linked with angiogenesis in EOC. Higher expression of VEGFR-2 is associated with more advanced disease. Further investigation of cyclin I in ovarian cancer is needed to evaluate if cyclin I may become a novel target for an anticancer therapy. [Copyright &y& Elsevier]

Abstract: Vascular endothelial growth factor (VEGF) is one of the strongest regulators of physiological and pathological angiogenesis. VEGF receptor 2 (VEGFR-2), the primary receptor for VEGF, is thought to mediate major functional effects of VEGF. Previously, we have localized both VEGF and VEGFR-2 in human hair follicles. In this study, we further defined the expression and roles of VEGFR-2 on human hair follicle dermal papilla (DP) cells. The expression of VEGFR-2 on DP cells was examined by reverse transcription-polymerase chain reaction (RT-PCR) and Western blot analysis separately, and localization of VEGFR-2 was defined by immunofluorescence. The effect of VEGF on DP cells was analyzed by MTT assays and specific inhibitors. Finally, the role of VEGF involved in the signaling pathways was investigated by Western blot. RT-PCR and Western blot analysis demonstrated the expression of VEGFR-2 on DP cells. Immunostaining for VEGFR-2 showed strong signal on cultured human DP cells in vitro. Exogenous VEGF165 stimulated proliferation of DP cells in a dose-dependent manner. Furthermore, this stimulation was blocked by a VEGFR-2 neutralizing antibody (MAB3571) and an ERK inhibitor (PD98059). VEGF165-induced phosphorylation of ERK1/2 was abolished by MAB3571 and PD98059, while the phosphorylation of p38, JNK and AKT were not changed by VEGF165. Taken together, VEGFR-2 is expressed on primary human hair follicle DP cells and VEGF induces proliferation of DP cells through VEGFR-2/ERK pathway, but not p38, JNK or AKT signaling. [Copyright &y& Elsevier]

Abstract: The angiogenic process begins with the cell proliferation and migration into the primary vascular network, and leads to vascularization of previously avascular tissues and organs as well to growth and remodeling of the initially homogeneous capillary plexus to form a new microcirculation. Additionally, an increase in microvascular permeability is a crucial step in angiogenesis. Vascular endothelial growth factor (VEGF) plays a central role in angiogenesis. We have previously reported that albendazole suppresses VEGF levels and inhibits malignant ascites formation, suggesting a possible effect on angiogenesis. This study was therefore designed to investigate the antiangiogenic effect of albendazole in non-cancerous models of angiogenesis. In vitro, treatment of human umbilical vein endothelial cells (HUVECs) with albendazole led to inhibition of tube formation, migration, permeability and down-regulation of the VEGF type 2 receptor (VEGFR-2). In vivo albendazole profoundly inhibited hyperoxia-induced retinal angiogenesis in mice. These results provide new insights into the antiangiogenic effects of albendazole. [Copyright &y& Elsevier]

Abstract: We investigated whether the gene expression of vascular endothelial growth factor (VEGF) and its receptors (VEGFR and neuropilin-1 [NRP-1]) could be specifically regulated during the megakaryocytic differentiation of human thrombopoietin (TPO)-dependent UT-7/TPO cells. Undifferentiated UT-7/TPO cells expressed a functional VEGFR-2, leading to VEGF binding and VEGF165-induced tyrosine phosphorylation, cell proliferation, and apoptosis inhibition. The megakaryocytic differentiation of UT-7/TPO cells on treatment with phorbol myristate acetate (PMA) was accompanied by a marked up-regulation of NRP-1 mRNA and protein expression and by an increase in VEGF-binding activity, which was mainly mediated by VEGFR-2. VEGF165 promoted the formation of complexes containing NRP-1 and VEGFR-2 in undifferentiated UT-7/TPO cells in a dose-dependent manner. Unlike human umbilical vein endothelial cells, PMA-differentiated UT-7/TPO cells exhibited complex formation between NRP-1 and VEGFR-2 even in the absence of VEGF165. These findings suggest that NRP-1–VEGFR-2-complex formation may contribute to effective cellular functions mediated by VEGF165 in megakaryocytic cells. [Copyright &y& Elsevier]

Abstract: Background: The VEGF–VEGF receptor (VEGFR) signaling axis has emerged as a promising target for cancer therapy, attributing to its vital role in tumor angiogenesis and growth. We have previously reported the regulation of epithelial ovarian cancer (EOC) invasion and migration by VEGF and the implication of VEGF-VEGFR-2 axis in lysophosphatidic acid (LPA)-induced EOC invasion. However, the expression profile of VEGF and VEGFRs in EOC, their association with tumor aggressiveness, and their regulation by LPA remain unclear. Objectives and methods: In this study, we examined the expression of VEGFR-1, VEGFR-2, neuropilin-1 (NRP-1), NRP-2, VEGF121, and VEGF165 in established EOC cell lines and assessed their correlation with cell invasiveness. Moreover, using an ovarian cancer tissue qPCR array, we analyzed VEGFR-2 expression across a panel of 48 tissues with different disease stages and histological grades. We also tested the effect of LPA on VEGF and VEGFR-2 expression and examined whether blocking VEGFR-2 by RNA interference (RNAi) affects LPA-induced EOC invasion. Results: We show that VEGF and VEGFR-2 expression correlates with cell invasiveness and VEGFR-2 expression in ovarian cancer tissues correlate with tumor grade. In addition, LPA, at 20 μM, significantly induced the expression of VEGF121, VEGF165, and VEGFR-2 in SKOV3 and DOV13 cells (P <0.05). VEGFR-2 small interference RNA (siRNA) transfection remarkably decreased LPA''s invasion-promoting effect (P <0.001) in SKOV3 cells without significantly decreasing SKOV3 cells'' basal invasiveness. In DOV13 cells, VEGFR-2 silencing significantly decreases both the basal level cell invasion and LPA''s invasion promoting effect (P <0.001). Conclusion: These results suggest that decreasing VEGFR-2 expression by RNAi may prove to be an effective method to reduce the metastatic potential of EOC cells exposed to elevated levels of LPA. [Copyright &y& Elsevier]

Abstract: Increased vascular permeability and vasodilation are responses usually elicited by snake envenomation. In this report, we isolated from Macrovipera lebetina venom two protein groups designated IC1 (Increasing Capillary1) and IC2 based on their activities on capillary permeability. Mass spectrometry analysis showed that IC1 contained four major proteins of 23,650, 24,306, 24,589 and 24,718Da, whereas IC2 contained three major proteins of 25,101, 25,194 and 25,298Da. N-terminal amino-acid sequencing revealed that IC1 and IC2 belong to the snake venom VEGF (svVEGF) family. IC1 and IC2 had a marked specificity for VEGFR-2, with affinities in the nanomolar range. Interestingly, they also bind to NRP1 and NRP2, with affinities in the micromolar range. This is the first report demonstrating that M. lebetina encodes several distinct svVEGFs, endowed with a capacity to interact with neuropilins. IC1 and IC2 could be valuable tools to understand the molecular properties of angiogenic factors and their receptors. [Copyright &y& Elsevier]

Abstract: Investigations were carried out to understand the molecular basis of the effect of ursolic acid on angiogenesis by analysing its effects on the expression of modulators of angiogenesis by HUVECs in culture. Treatment with ursolic acid increased the expression of adhesion molecules such as E-selectin, CD-31 and I-CAM, upregulated angiogenic growth factors such as VEGF and FGF-2 and their receptors and caused increase in the ratio of PGE2 to PGD2. Reversal of the effect of ursolic acid by inhibition of PI3K-Akt pathway and increase in the level of phospho Akt suggest that the ursolic acid effect is mediated through PI3K-Akt pathway. [Copyright &y& Elsevier]

Abstract: Epidermal growth factor receptor (EGFR) targeting agents such as kinase inhibitors reduce tumor growth and progression. We have previously reported that EGFR is not only expressed by the tumor cells but by the tumor endothelial cells (EC) as well (Amin, D. N., Hida, K., Bielenberg, D. R., Klagsbrun, M., 2006. Tumor endothelial cells express epidermal growth factor receptor (EGFR) but not ErbB3 and are responsive to EGF and to EGFR kinase inhibitors. Cancer Res. 66, 2173–80). Thus, targeting tumor blood vessel EGFR may be a viable strategy for tumor growth inhibition. We describe here a melanoma xenograft model where the tumor cells express very little or no EGFR but the tumor blood vessels express activated EGFR. The EGFR kinase inhibitor, gefitinib (Iressa), retarded tumor growth with a size decrease of 38% compared to control mice, ostensibly due to targeting of the blood vessels. EC were isolated from tumors of gefitinib-treated mice. These EC were unable to proliferate in response to EGF and displayed relatively weaker activation of MAPK and AKT signaling in response to EGF compared to tumor EC isolated from vehicle-treated mice. In contrast, the tumor EC from gefitinib-treated mice expressed higher levels of VEGFR-2 both at the mRNA and protein level. In addition, these cells were less sensitive to EGFR kinase inhibitors in vitro but more sensitive to a VEGFR-2 kinase inhibitor. These results suggest that in tumor EC from gefitinib-treated mice there is a switch from dependence on EGFR activity to signaling via VEGFR-2. Our data provide a molecular rationale for combination therapies targeting both EGF and VEGF signaling on the tumor vasculature. [Copyright &y& Elsevier]

Abstract: Pathological angiogenesis in the retina and underlying choroid is a major cause of visual impairment in all age groups. The last decade has seen an explosion in the clinical availability of antiangiogenic compounds. Emphasis has been placed on inhibitors of the VEGF signaling pathway and considerable success has been achieved with aptamers and antibodies that bind VEGF. However, regression of neovascularization is rarely permanent and the regrowth of new vessels, often within a few months, requires multiple applications of drug. A number of antiangiogenic factors such as IGFBP3, SDF-1 blockers, PEDF, γ-secretase, Delta-like ligand 4, and integrin antagonists have been identified, which act either indirectly on the VEGF system or independent of it. The importance of other candidates such as HIF-1α and protein kinase CK2, which act as “master” regulators of angiogenesis, offer realistic alternative targets for pharmacological intervention. The concept of combination therapy is rapidly gaining interest in the eye field and co-administration of two angiogenic agents (e.g., a CK2 inhibitor with a somatostatin analog, octreotide) are often significantly more effective at inhibiting retinal angiogenesis than either drug alone. The following review will discuss the current therapies available for aberrant ocular angiogenesis, consider new candidate targets for development of antiangiogenic compounds and emphasize the importance of combinatorial pharmacological agents in the treatment of such a dynamic cellular event as angiogenesis. [Copyright &y& Elsevier]

Abstract: Regulation of VEGFR-2 (Quek1) is an important mechanism during blood vessel formation. In the paraxial mesoderm, Quek1 expression is restricted to the lateral portion of the somite and later to sclerotomal cells surrounding the neural tube. By implanting FGF 8b/8c or SU 5402 beads into the paraxial mesoderm, we show that FGF8 in addition to BMP4 from the intermediate mesoderm (IM) is a positive regulator of VEGFR-2 (Quek1) expression in the quail embryo. The expression of Quek1 in the medial somite half is normally repressed by the notochord and Sfrps-expression in the neural tube. Over-expression of Wnt 1/3a also results in an up-regulation of Quek1 expression in the somites. We also show that up-regulation of FGF8/Wnt 1/3a leads to an increase in the number of endothelial cells, whereas inhibition of FGF and Wnt signaling by SU 5402 and Sfrp-2 results in a loss of endothelial cells. Our results demonstrate that the regulation of Quek1 expression in the somites is mediated by the cooperative actions of BMP4, FGF8 and Wnt-signaling pathways. [Copyright &y& Elsevier]

Abstract: HESR1 is a basic helix–loop–helix transcription factors regulated by the Notch signaling pathway in vertebrate and Drosophila embryos, and is related to the HES/Hairy/E (sp1) family. HESR1 is a downstream target of Notch in endothelial cells and could be an effector of Notch signaling in these cells. HESR1 is necessary for the induction of a tubular network and for continued maintenance of mature and quiescent blood vessels. To examine the role of HESR1 in retinal neovascularization, we transfected retinal vascular endothelial cells (HRCECs) with the HESR1 gene and studied its effects on the expression of angiogenic factors, on the proliferation and migration of endothelial cells, and on the formation of tube-like structures (TLSs). Overexpression of HESR1 downregulated VEGFR-2 expression, upregulated occludin expression, inhibited the migration and proliferation of HRCECs, and inhibited the formation of TLSs. Thus, HESR1 plays a key role in the finely tuned network of molecules involved in the regulation of retinal vascular homeostasis. HESR1 seems to inhibit the vessel-promoting effects of VEGF, shift endothelial cells from a proliferative state to a quiescent state, and restore normal vessel structures. Expression of the HESR1 gene in retinal vascular endothelial cells may protect retinal blood vessels and may be useful in the treatment of diseases involving damage to the retinal vasculature, including diabetic retinopathy, age-related macular degeneration, and retinal vein occlusion. [Copyright &y& Elsevier]

Abstract: Vascular endothelial growth factor (VEGF) and its receptor VEGFR-2 play important roles in mitogenesis and chemotaxis of endothelial cells. In normal human skin, VEGF is expressed and secreted by epidermal keratinocytes. Emerging data suggest that keratinocyte-derived VEGF targets other cell types besides the dermal endothelial cells. We have recently showed that keratinocytes from human normal skin expressed all five known VEGF receptors and co-receptors (neuropilin 1 and 2). To define the functional significance of VEGFR-2 in epidermis, we examined its role in a keratinocyte cell line, HaCaT cells, in response to VEGF treatment. Expression of VEGFR-2 on HaCaT cells was confirmed at both RNA and protein levels and was regulated by VEGF165 treatment. Treatment of HaCaT cells with VEGF165 induced tyrosine-autophosphorylation of VEGFR-2 and phosphorylation of PLC-γ and p44/42 MAPK in a time-dependent manner. Preincubation with a neutralizing antibody for VEGFR-2 (MAB3571) completely abrogated these phosphorylation effects. Furthermore, VEGF165 stimulated proliferation and migration of HaCaT cells, and this effect was significantly blocked by a pretreatment with MAB3571. Neutralizing VEGFR-2 in HaCaT cells increased cell adhesion during culture. Our results suggest that VEGFR-2 expressed on HaCaT cells plays a crucial role in VEGF-mediated regulation of cell activity. [Copyright &y& Elsevier]

Abstract: The mechanisms controlling blood vessel formation during early embryonal development have only partly been elucidated. Shb is an adaptor protein previously implicated in the angiogenic response to vascular endothelial growth factor (VEGF). To elucidate a possible role of Shb in embryonic vascular development, wild-type and SH2 domain mutated (R522K) Shb were overexpressed in murine embryonic stem (ES) cells. Embryoid bodies (EBs) differentiating from Shb-overexpressing ES cells in vitro were stained for CD31 or VEGFR-2 to visualize the formation of vascular structures. We found that Shb promotes the outgrowth of blood vessels in EBs both in the absence and presence of growth factors. This response may be the consequence of an increased number of VEGFR-2 positive cells at an early stage of EB development, a finding corroborated by both immunostaining and real-time RT-PCR. In addition, Shb overexpression upregulated the expression of PDGFR-β, CD31, CD41 and Tal1. Cells co-expressing VEGFR-2 and PDGFR-β were commonly observed when Shb was overexpressed and inhibition of PDGF-BB signaling reduced the amount of VEGFR-2 mRNA under these conditions. EBs expressing the Shb R522K-mutant did not form vascular structures. Microarray analysis of VEGFR-2/CD31 positive cells after 6 days of differentiation revealed numerous changes of expression of genes relating to an endothelial/hematopoietic phenotype in response to Shb overexpression. The findings suggest that Shb may play a crucial role during early ES cell differentiation to vascular structures by transducing VEGFR-2 and PDGFR-β signals. [Copyright &y& Elsevier]

Abstract: Objective : Lysophosphatidic acid (LPA) stimulates ovarian tumor growth partially via induction of VEGF expression through transcriptional activation. Previous studies have shown that LPA induces epithelial ovarian cancer (EOC) in vitro metastasis. In this study, we examined the role of VEGF in LPA-induced EOC invasion and migration and underlying mechanisms. Methods : The invasiveness of DOV13 cells was determined by in vitro basement membrane Matrigel invasion assay. Ovarian carcinoma cellular migration was quantified by the colloidal gold migration assay. Matrix metalloproteinase (MMP)-2 secretion and activation were detected by gelatin zymography. Urokinase type plasminogen activator (uPA) activity was determined by a coupled colorimetric assay measuring the activity of generated plasmin. Student''s t test and one-way ANOVA were used for statistical analysis. Results : Using a VEGF neutralizing monoclonal antibody (mAb), we show that LPA-induced EOC invasion is dependent upon VEGF. Using the selective VEGF receptor (VEGFR)-2 inhibitor, SU1498, LPA-induced EOC invasion and migration were significantly inhibited in a concentration-dependent manner. In addition, SU1498 inhibits MMP-2 secretion and uPA activity in ovarian cancer DOV13 cells. At 5 and 20 μM, SU1498 almost completely inhibited the activity of MMP-2 and uPA. SU1498 also decreases the LPA-induced increase of uPA activity in DOV13 cells. Conclusions : Our results show that LPA-induced EOC invasion is at least partially mediated by VEGF. Further, the VEGFR-2-mediated signaling transduction pathway may be involved in LPA-induced EOC invasion and migration by regulating the secretion and activation of MMP-2 and uPA. [Copyright &y& Elsevier]

Abstract: Regulation of VEGFR-2 (Quek1) is an important mechanism during blood vessel formation. In the paraxial mesoderm, Quek1 expression is restricted to the lateral portion of the somite and later to sclerotomal cells surrounding the neural tube. By grafting of either intermediate mesoderm or BMP4 beads into the paraxial mesoderm, we show that BMP4 is a positive regulator of VEGFR-2 (Quek1) expression in the quail embryo. Separation of somites from intermediate mesoderm leads to down-regulation of Quek1 expression. The expression of Quek1 in the medial somite half is normally repressed by the notochord and becomes up-regulated and lateromedially expanded after separation of the notochord. Our results show that up-regulation of BMP4 leads to an increase of the number of blood vessels, whereas inhibition of BMP4 by noggin results in a reduction of blood vessels. [Copyright &y& Elsevier]

VEGFR-3 is essential for vascular development and maintenance of lymphatic vessel’s integrity. Little is known about its cooperative effect with other receptors of the same family. Contrary to VEGFR-2, stimulation of VEGFR-3 by VEGF-C and -D failed to enhance its phosphorylation either in HEK293T or in PAE cells. These ligands were unable to induce angiogenesis of PAEC expressing VEGFR-3 alone. In the presence of VEGFR-2, VEGF-C and -D induced heterodimerization of VEGFR-3 with VEGFR-2. This heterodimerization was associated with enhanced VEGFR-3 phosphorylation and subsequent cellular responses as evidenced by the formation of capillary-like structures in PAE cells and proliferation of primary human endothelial cells expressing both receptors. Taken together, these results show for the first time that VEGFR-3 needs to be associated to VEGFR-2 to induce ligand-dependent cellular responses. [Copyright &y& Elsevier]

VE-cadherin plays a critical role in cell–cell interactions by forming adherens junctions in endothelial cells. VE-cadherin has increasingly been implicated in the cell signaling cascades initiated by the activation of growth factor receptors. Vascular endothelial growth factor receptor 2 (VEGFR-2) is present in regions of cell–cell contact and coimmunoprecipitates with VE-cadherin. In this study, we report that stable overexpression of VE-cadherin in two different endothelial cells induced an increase in VEGFR-2 protein levels. The increase in VEGFR-2 was also induced by overexpression of other classical cadherins such as E-cadherin or N-cadherin. Removing the extracellular domain of VE-cadherin abolished this effect, and a truncated form of VE-cadherin lacking the intracellular domain decreased VEGFR-2 instead of increasing it. VE-cadherin-induced changes in VEGFR-2 levels were paralleled by a corresponding shift in the VEGF-dependent activation of MAPK signaling, which demonstrated the functional relevance of varying the VEGFR-2 levels. Since VE-cadherin upregulated endogenous VEGFR-2 or exogenously expressed VEGFR-2, we hypothesized that the mechanism may be posttranslational. Indeed, the half-life of VEGFR-2 was 70 min in control cells whereas in cells overexpressing VE-cadherin the half-life was extended to 146 min. These results support the existence of a novel layer of functional regulation of VEGFR-2 by VE-cadherin. [Copyright &y& Elsevier]

Inhalant nitrites are drugs of abuse that have been shown to enhance tumor growth rate in mice and are epidemiologically linked to an increased risk of Kaposi’s sarcoma. Because nitrites produce nitric oxide, we hypothesized that their toxicological effects might be partly mediated via regulation of angiogenic factors such as vascular endothelial growth factor (VEGF). Preliminary studies showed that isobutyl nitrite (ISBN) incubation stimulated VEGF protein expression in J774 macrophage cells. C57BL/6 mice exposed to ISBN in air exhibited significant up-regulation of VEGF protein and mRNA in the liver, but not in the lung. Liver mRNA expression of VEGF receptor 2 (VEGFR-2), VEGFR-3, Smad5, and Smad7 was also significantly altered. These results demonstrate that in vivo exposure to an inhalant nitrite results in altered tissue expression of VEGF and its receptors, suggesting that some of its toxicological effects may be mediated partly through a mechanism involving angiogenesis. [Copyright &y& Elsevier]

Angiogenesis and lymphangiogenesis are regulated by members of the vascular endothelial growth factor (VEGF) family of cytokines, which mediate their effects via tyrosine kinase VEGF receptors -1, -2, and -3. We have used wild-type and mutant forms of VEGFs -A, -B, and -C, a pan-VEGFR tyrosine kinase inhibitor (SU5416) as well as neutralizing anti-VEGFR-2 antibodies, to determine which VEGF receptor(s) are required for bovine endothelial cell invasion and tube formation in vitro. This was compared to the ability of these cytokines to induce expression of members of the plasminogen activator (PA)-plasmin system. We found that cytokines which bind VEGFR-2 (human VEGF-A, human VFM23A, human VEGF-CΔNΔC, and rat VEGF-C152) induced invasion, tube formation, urokinase-type-PA, tissue-type-PA, and PA inhibitor-1, invasion and tube formation as well as signaling via the MAP kinase pathway were efficiently blocked by SU5416 and anti-VEGFR-2 antibodies. In contrast, cytokines and mutants which exclusively bind VEGFR-1 (human VFM17 and human VEGF-B) had no effect on invasion and tube formation or on the regulation of gene expression. We were unable to identify cytokines which selectively stimulate bovine VEGFR-3 in our system. Taken together, these findings point to the central role of VEGFR-2 in the angiogenic signaling pathways induced by VEGF-CΔNΔC and VEGF-A. [Copyright &y& Elsevier]

VEGF family members play important roles in angiogenesis and vascular permeability. VEGF-A-transgenic mice showed an increased vascularization with edema due to hyper-vascular permeability and subcutaneous hemorrhage as side effects. VEGF-A binds and activates two receptors, VEGFR-1 (Flt-1) and VEGFR-2 (KDR/Flk-1). To dissect the signals of these two receptors, we generated transgenic mice overexpressing either the VEGFR-2-specific ligand VEGF-ENZ-7 or VEGFR-1-specific ligand PlGF-II under the control of the Keratin-14 promoter. VEGF-E-mice showed a significant increase in vascularization (about 10-fold compared to control mice) in subcutaneous tissues, whereas PlGF-mice showed only a 2–3-fold increase. Interestingly, VEGF-E-mice did not show any clear edematous lesions or hemorrhagic spots on the skin. Microscopically, VEGF-E-induced capillary networks have a well organized structure with the recruitment of pericytes. These results indicate that VEGF-E is a new angiogenic agent with less side effects for clinical usage. [Copyright &y& Elsevier]

Angiogenesis is essential for normal homeostasis, wound healing, and tumor growth and involves a switch in endothelial cell (EC) phenotype from quiescence to migration, proliferation and network formation, and back to quiescence. The notch signaling pathway is critically involved in cell fate decisions during development, and mice deficient in several notch/notch ligand genes have vascular phenotypes. Here we show that notch signaling is activated during EC capillary-like network formation in vitro and that EC express transcripts for notch 1, notch 4, the notch ligand delta 4, and the putative notch processing enzymes ADAM-10 and presenilin. Expression of dominant negative notch blocks network formation; however, constitutively active notch (NICD) does not induce morphologic changes. Furthermore, both EC network formation and expression of activated notch 1 or notch 4 induce expression of the bHLH transcription factor HESR-1 and downregulate the known HESR-1 target VEGFR-2 (KDR). Notch-mediated reduction in VEGFR-2 expression results in decreased EC proliferation in response to VEGF but not bFGF. These data suggest that HESR-1 may be involved in the phenotypic changes that characterize the progression from EC proliferation and migration to network formation and quiescence. [Copyright &y& Elsevier]

Series of salicylate-curcumin mimics were synthesized of potential antiproliferative (against A431 and HCT116 cell lines) and anti-SARS-CoV-2 properties. [Display omitted] • Salicylate-curcumin mimics were prepared in a facile pathway. • They reveal promising properties against A431 and HCT116 cell lines. • They are multi-targeted inhibitors against VEGFR-2 and EGFR. • Docking studies support the EGFR inhibitory properties. • Some of them are anti-SARS-CoV-2 with high SI. Series of piperidone-salicylate conjugates were synthesized through the reaction of 3 E ,5 E -bis(arylidene)-4-piperidones with the appropriate acid chloride of acetylsalicylate in the presence of triethylamine. All the synthesized conjugates reveal antiproliferative properties against A431 (squamous skin) cancer cell line with potency higher than that of 5-fluorouracil. Many of the synthesized agents also exhibit promising antiproliferative properties against HCT116 (colon) cancer cell line, of which 5o and 5c are the most effective with 12.9, 9.8 folds potency compared with Sunitinib. Promising activity is also shown against MCF7 (breast) cancer cell line with 1.19, 1.12 folds relative to 5-fluorouracil. PI-flow cytometry of compound 5c supports the arrest of cell cycle at G1-phase. However, compound 5o and Sunitinib arrest the cell cycle at S-phase. The synthesized conjugates can be considered as multi-targeted tyrosine kinase inhibitors due to the promising properties against VEGFR-2 and EGFR in MCF7 and HCT116. CDOCKER studies support the EGFR inhibitory properties. Compounds 5p and 5i possessing thienylidene heterocycle are anti-SARS-CoV-2 with high therapeutic indices. Many of the synthesized agents show enhanced COX-1/2 properties than aspirin with better selectivity index towards COX-2 relative to COX-1. The possible applicability of the potent candidates discovered as antitumor and anti-SARS-CoV-2 is supported by the safe profile against normal (non-cancer, RPE1 and VERO-E6) cells. [ABSTRACT FROM AUTHOR]