Vascular endothelial growth factor (VEGF) receptors: drugs and new inhibitors

Regulation of VEGF gene expression by bisacridine derivative through promoter i-motif for cancer treatment

BACKGROUND

Vascular endothelial growth factor (VEGF) is overexpressed in most malignant tumors, which has important impact on tumor angiogenesis and development. Its gene promoter i-motif structure formed by C-rich sequence can regulate gene expression, which is a promising new target for anti-tumor therapy.

METHODS

We screened various compounds and studied their effects on VEGF through extensive experiments, including SPR, MST, TO displacement, FRET, CD, ESI-MS, NMR, MTT, clone formation, qPCR, Western blot, dual-luciferase reporter assay, immunofluorescence, cell scrape, apoptosis, transwell assay, and animal model.

RESULTS

After extensive screening, bisacridine derivative B09 was found to have selective binding and stabilization to VEGF promoter i-motif, which could down-regulate VEGF gene expression. B09 showed potent inhibition on MCF-7 and HGC-27 cell proliferation and metastasis. B09 significantly inhibited tumor growth in xenograft mice model with HGC-27 cells, showing decreased VEGF expression analyzed through immunohistochemistry.

CONCLUSION

B09 could specifically regulate VEGF gene expression, possibly through interacting with promoter i-motif structure. As a lead compound, B09 could be further developed for innovative anti-cancer agent targeting VEGF.

Amiloride reduces fructosamine-3-kinase expression to restore sunitinib sensitivity in renal cell carcinoma

The kidney is a vital organ responsible for water and sodium metabolism, while the primary function of amiloride is to promote the excretion of water and sodium. We investigated amiloride enhanced the sunitinib sensitivity in RCC. We found both sunitinib and amiloride displayed cytotoxicity and exerted the synergy effect in RCC cells in vivo and in vitro arrays. Protein expression profiles were screened via MS/TMT, revealing that FN3K was upregulated in the sunitinib group, and rescued in amiloride and the combination administration. Exogenous FN3K could promote proliferation, invasion and metastasis and decrease the sensitivity of Caki-1 cells to sunitinib, also, exogenous FN3K up-regulated VEGFR2 expression and activated AKT/mTOR signal pathway. More FN3K and VEGFR2 accumulated in R-Caki-1 cells and rescued by amiloride treatment. Co-IP and IF confirmed the interaction between FN3K and VEGFR2. In conclusion, FN3K depletion mediated VEGFR2 disruption promotes amiloride synergized the anti-RCC activity of sunitinib.

Recent advances and future directions on small molecule VEGFR inhibitors in oncological conditions

"A journey of mixed emotions" is a quote that best describes the progress chart of vascular endothelial growth factor receptor (VEGFR) inhibitors as cancer therapeutics in the last decade. Exhilarated with the Food and Drug Administration (FDA) approvals of numerous VEGFR inhibitors coupled with the annoyance of encountering the complications associated with their use, drug discovery enthusiasts are on their toes with an unswerving determination to enhance the rate of translation of VEGFR inhibitors from preclinical to clinical stage. The recently crafted armory of VEGFR inhibitors is a testament to their growing dominance over other antiangiogenic therapies for cancer treatment. This review perspicuously underscores the earnest attempts of the researchers to extract the antiproliferative potential of VEGFR inhibitors through the design of mechanistically diverse structural assemblages. Moreover, this review encompasses sections on structural/molecular properties and physiological functions of VEGFR, FDA-approved VEGFR inhibitors, and hurdles restricting the activity range/clinical applicability of VEGFR targeting antitumor agents. In addition, tactics to overcome the limitations of VEGFR inhibitors are discussed. A clear-cut viewpoint transmitted through this compilation can provide practical directions to push the cart of VEGFR inhibitors to advanced-stage clinical investigations in diverse malignancies.

Utility of sulfachloropyridazine in the synthesis of novel anticancer agents as antiangiogenic and apoptotic inducers

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 IC50 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.

Computational repurposing of oncology drugs through off-target drug binding interactions from pharmacological databases

PURPOSE

Systematic repurposing of approved medicines for another indication may accelerate drug development in oncology. We present a strategy combining biomarker testing with drug repurposing to identify new treatments for patients with advanced cancer.

METHODS

Tumours were sequenced with the Illumina TruSight Oncology 500 (TSO-500) platform or the FoundationOne CDx panel. Mutations were screened by two medical oncologists and pathogenic mutations were categorised referencing literature. Variants of unknown significance were classified as potentially pathogenic using plausible mechanisms and computational prediction of pathogenicity. Gain of function (GOF) mutations were evaluated through repurposing databases Probe Miner (PM), Broad Institute Drug Repurposing Hub (Broad Institute DRH) and TOPOGRAPH. GOF mutations were repurposing events if identified in PM, not indexed in TOPOGRAPH and excluding mutations with a known Food and Drug Administration (FDA)-approved biomarker. The computational repurposing approach was validated by evaluating its ability to identify FDA-approved biomarkers. The total repurposable genome was identified by evaluating all possible gene-FDA drug-approved combinations in the PM dataset.

RESULTS

The computational repurposing approach was accurate at identifying FDA therapies with known biomarkers (94%). Using next-generation sequencing molecular reports (n = 94), a meaningful percentage of patients (14%) could have an off-label therapeutic identified. The frequency of theoretical drug repurposing events in The Cancer Genome Atlas pan-cancer dataset was 73% of the samples in the cohort.

CONCLUSION

A computational drug repurposing approach may assist in identifying novel repurposing events in cancer patients with no access to standard therapies. Further validation is needed to confirm a precision oncology approach using drug repurposing.

Novel quinazolines bearing 1,3,4-thiadiazole-aryl urea derivative as anticancer agents: design, synthesis, molecular docking, DFT and bioactivity evaluations

A novel series of 1-(5-((6-nitroquinazoline-4-yl)thio)-1,3,4-thiadiazol-2-yl)-3-phenylurea derivatives 8 were designed and synthesized to evaluate their cytotoxic potencies. The structures of these obtained compounds were thoroughly characterized by IR, 1H, and 13C NMR, MASS spectroscopy and elemental analysis methods. Additionally, their in vitro anticancer activities were investigated using the MTT assay against A549 (human lung cancer), MDA-MB231 (human triple-negative breast cancer), and MCF7 (human hormone-dependent breast cancer). Etoposide was used as a reference marketed drug for comparison. Among the compounds tested, compounds 8b and 8c demonstrated acceptable antiproliferative activity, particularly against MCF7 cells. Considering the potential VEGFR-2 inhibitor potency of these compounds, a molecular docking study was performed for the most potent compound, 8c, to determine its probable interactions. Furthermore, computational investigations, including molecular dynamics, frontier molecular orbital analysis, Fukui reactivity descriptor, electrostatic potential surface, and in silico ADME evaluation for all compounds were performed to illustrate the structure-activity relationship (SAR).

Design, Synthesis and Biological Assessment of N'-(2-Oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazides as Potential Anti-Proliferative Agents toward MCF-7 Breast Cancer

Breast cancer is a serious threat to the health and lives of women. Two novel series of N'-(2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazides and 1-(aryl)-3-(6-methylimidazo[2,1-b]thiazol-5-yl)ureas were designed, synthesized and investigated for their anticancer efficacy against the MCF-7 breast cell line. Three compounds of the first series showed potent activity toward MCF-7 with IC50 in the range 8.38-11.67 µM, respectively, as compared to Sorafenib (IC50 = 7.55 µM). N'-(1-butyl-2-oxoindolin-3-ylidene)-6-methylimidazo[2,1-b]thiazole-5-carbohydrazide inhibited VEGFR-2 with IC50 = 0.33 µM when compared with Sorafenib (IC50 = 0.09 µM). Furthermore, this compound was introduced to PCR assessment, where it increased Bax, caspase 8, caspase 9 and cytochrome C levels by 4.337-, 2.727-, 4.947- and 2.420-fold, respectively, while it decreased levels of Bcl-2, as the anti-apoptotic gene, by 0.359-fold when compared to the untreated control MCF-7. This compound was also arrested in the G2/M phase by 27.07%, compared with 11.31% for the control MCF-7. Furthermore, it induced early and late apoptosis in MCF-7. In addition, a molecular docking study in the VEGFR-2 active site was performed to assess the binding profile for the most active compounds. Moreover, ADME parameters of the targeted compounds were also evaluated.

Molecular mechanisms and therapeutic applications of huaier in breast cancer treatment

Breast cancer is one of the most common female malignant tumors today and represents a serious health risk for women. Although the survival rate and quality of life of patients with breast cancer are improving with the continuous development of medical technology, metastasis, recurrence, and drug resistance of breast cancer remain a significant problem. Huaier, a traditional Chinese medicine (TCM) fungus, is a type of Sophora embolism fungus growing on old Sophora stems. The polysaccharides of Trametes robiniophila Murr (PS-T) are the main active ingredient of Huaier. There is increasing evidence that Huaier has great potential in breast cancer treatment, and its anti-cancer mechanism may be related to a variety of biological activities, such as the inhibition of cell proliferation, metastasis, tumor angiogenesis, the promotion of cancer cell death, and regulation of tumor-specific immunity. There is growing evidence that Huaier may be effective in the clinical treatment of breast cancer. This review systematically summarizes the basic and clinical studies on the use of Huaier in the treatment of breast cancer, providing useful information to guide the clinical application of Huaier and future clinical studies.

Role of endothelin ETA receptors in the hypertension induced by the VEGFR-2 kinase inhibitors axitinib and lenvatinib in conscious freely-moving rats

Receptor tyrosine kinase inhibitors (RTKIs) suppress tumour growth by targeting vascular endothelial growth factor receptor 2 (VEGFR-2) which is an important mediator of angiogenesis. Here, we demonstrate that two potent RTKIs, axitinib and lenvatinib, are associated with hypertensive side effects. Doppler flowmetry was used to evaluate regional haemodynamic profiles of axitinib and lenvatinib. Male Sprague Dawley rats (350-500 g) were instrumented with Doppler flow probes (renal and mesenteric arteries and descending abdominal aorta) and catheters (jugular vein and distal abdominal aorta, via the caudal artery). Rats were dosed daily with axitinib (3 or 6 mg.kg-1) or lenvatinib (1 or 3 mg.kg-1) and regional haemodynamics were recorded over a maximum of 4 days. Both RTKIs caused significant (p < 0.05) increases in mean arterial pressure (MAP), which was accompanied by significant (p < 0.05) vasoconstriction in both the mesenteric and hindquarters vascular beds. To gain insight into the involvement of endothelin-1 (ET-1) in RTKI-mediated hypertension, we also monitored heart rate (HR) and MAP in response to axitinib or lenvatinib in animals treated with the ETA receptor selective antagonist sitaxentan (5 mg.kg-1) or the mixed ETA/ETB receptor antagonist bosentan (15 mg.kg-1) over two days. Co-treatment with bosentan or sitaxentan markedly reduced the MAP effects mediated by both RTKIs (p < 0.05). Bosentan, but not sitaxentan, also attenuated ET-1 mediated increases in HR. These data suggest that selective antagonists of ETA receptors may be appropriate to alleviate the hypertensive effects of axitinib and lenvatinib.

New 2-alkoxycyanopyridine derivatives as inhibitors of EGFR, HER2, and DHFR: Synthesis, anticancer evaluation, and molecular modeling studies

New series of substituted 2-alkoxycyanopyridine derivatives were synthesized and evaluated for their in vitro and in vivo anticancer activities. Comparing the evaluated activities against cancer cell lines to the broad-spectrum anticancer doxorubicin, and the kinase inhibitor sorafenib, compounds 3a, 4b, 4c, 7a, and 8d demonstrated superior anticancer efficacy with elevated safety profiles and selectivity indices, particularly against MCF7 breast cancer. For exploration of their mechanism of action, assays for inhibition of EGFR, HER2 kinase, and DHFR were performed. The promising synthesized compounds exhibited potent dual kinase EGFR/HER2 inhibitory activity with IC50values of 0.248/0.156 μM for 4b and 0.138/0.092 μM for 4c. Additionally, with IC50 values of 0.138 and 0.193 M, respectively, 4b and 4c had the greatest DHFR inhibitory activity that was comparable to methotrexate. In the MCF7 breast cancer cell line, they caused arrest at the S phase of the cell cycle and exhibited apoptosis induction activity. With restored caspase-3 immunoexpression, the anti-breast cancer assay performed in vivo of 4b and 4c demonstrated a substantial decrease in tumor volume. Results from molecular modeling were in agreement with biological assays proving the importance of the 3-caynopyridine, two substituted phenyl rings attached to central pyridine ring, and propoxy side chain moieties for binding with the receptors. As 4c works by inhibiting both EGFR/HER2 kinase, DHFR enzymes, in addition to cellular apoptosis, it could be viewed as a model of compounds possessing a multi-targeting anticancer activity. Collectively, compounds 4b and 4c might represent prototypes for further development as anticancer molecules.

Quinazoline-based VEGFR-2 inhibitors as potential anti-angiogenic agents: A contemporary perspective of SAR and molecular docking studies

Angiogenesis, the formation of new blood vessels from the existing vasculature, is pivotal in the migration, growth, and differentiation of endothelial cells in normal physiological conditions. In various types of tumour microenvironments, dysregulated angiogenesis plays a crucial role in supplying oxygen and nutrients to cancerous cells, leading to tumour size growth. VEGFR-2 tyrosine kinase has been extensively studied as a critical regulator of angiogenesis; thus, inhibition of VEGFR-2 has been widely used for cancer treatments in recent years. Quinazoline nucleus is a privileged and versatile scaffold with a broad range of pharmacological activity, especially in the field of tyrosine kinase inhibitors with more than twenty small molecule inhibitors approved by the US Food and Drug Administration in the last two decades. As of now, the U.S. FDA has approved eleven small chemical inhibitors of VEGFR-2 for various types of malignancies, with a prime example being vandetanib, a quinazoline derivative, which is a multi targeted kinase inhibitor used for the treatment of late-stage medullary thyroid cancer. Despite of prosperous discovery and development of VEGFR-2 down regulator drugs, there still exists limitations in clinical efficacy, adverse effects, a high rate of clinical discontinuation and drug resistance. Therefore, there is an urgent need for the design and synthesis of more selective and effective inhibitors to tackle these challenges. Through the gathering of this review, we have strived to broaden the extent of our view over the entire scope of quinazoline-based VEGFR-2 inhibitors. Herein, we give an overview of the importance and advancement status of reported structures, highlighting the SAR, biological evaluations and their binding modes.

Red Light-Triggered Anti-Angiogenic and Photodynamic Combination Therapy of Age-Related Macular Degeneration

Choroidal neovascularization (CNV) is the key pathological event of wet age-related macular degeneration (wAMD) leading to irreversible vision loss. Currently, anti-angiogenic therapy with anti-vascular endothelial growth factor (VEGF) agents has become the standard treatment for wAMD, while it is still subject to several limitations, including the safety concerns of monthly intravitreal administration and insufficient efficacy for neovascular occlusion. Combined therapy with photodynamic therapy (PDT) and anti-angiogenic agents has emerged as a novel treatment paradigm. Herein, a novel and less-invasive approach is reported to achieve anti-angiogenic and photodynamic combination therapy of wAMD by intravenous administration of a photoactivatable nanosystem (Di-DAS-VER NPs). The nanosystem is self-assembled by reactive oxygen species (ROS)-sensitive dasatinib (DAS) prodrug and photosensitizer verteporfin (VER). After red-light irradiation to the diseased eyes, intraocular release of anti-angiogenic DAS is observed, together with selective neo-vessels occlusion by VER-generated ROS. Notably, Di-DAS-VER NPs demonstrates promising therapeutic efficacy against CNV with minimized systemic toxicity. The study enables an efficient intravenous wAMD therapy by integrating a photoactivation process with combinational therapeutics into one simple nanosystem.

Novel 3-phenylquinazolin-2,4(1H,3H)-diones as dual VEGFR-2/c-Met-TK inhibitors: design, synthesis, and biological evaluation

Multitarget anticancer drugs are more superior than single target drugs regarding patient compliance, drug adverse effects, drug-drug interactions, drug resistance as well as pharmaceutical industry economics. Dysregulation of both VEGFR-2 and c-Met tyrosine kinases (TKs) could result in development and progression of different human cancers. Herein, we reported a novel series of 3-phenylquinazolin-2,4(1H,3H)-diones with thiourea moiety as dual VEGFR-2/c-Met TKs. Compared to sorafenib, cabozantinib went behind VEGFR-2 inhibition to target c-Met TK. The dual VEGFR-2/c-Met inhibitory activity of cabozantinib is due to a longer HB domain than that of sorafenib. Based on pharmacophore of cabozantinib analogues, we designed new dual VEGFR-2/c-Met TKs. We synthesized the target compounds via a new single pot three-component reaction. The cytotoxic activity of synthesized compounds was conducted against HCT-116 colorectal cancer cell line. Compounds 3c and 3e exhibited the highest cytotoxic activity against HCT-116 cell line (IC50 1.184 and 3.403 µM, respectively). The in vitro enzyme inhibitory activity was carried out against both VEGFR-2 and c-Met TKs. Compound 3e has the highest inhibitory activity against both VEGFR-2/c-Met (IC50 = 83 and 48 nM, respectively). Docking studies showed that α-oxo moiety in quinazoline ring formed hydrogen bond HB with Met1160 residue in the adenine region of c-Met TK.

A novel thieno[2,3-d]pyrimidine derivative inhibiting vascular endothelial growth factor receptor-2: A story of computer-aided drug discovery

Following the pharmacophoric features of vascular endothelial growth factor receptor 2 (VEGFR-2) inhibitors, a novel thieno[2,3-d]pyrimidine derivative has been designed and its activity against VEGFR-2 has been demonstrated by molecular docking studies that showed an accurate binding mode and an excellent binding energy. Furthermore, the recorded binding was confirmed by a series of molecular dynamics simulation studies, which also revealed precise energetic, conformational, and dynamic changes. Additionally, molecular mechanics with generalized Born and surface area solvation and polymer-induced liquid precursors studies were conducted and verified the results of the MD simulations. Next, in silico absorption, distribution, metabolism, excretion, and toxicity studies have also been conducted to examine the general drug-like nature of the designed candidate. According to the previous results, the thieno[2,3-d]pyrimidine derivative was synthesized. Fascinatingly, it inhibited VEGFR-2 (IC50  = 68.13 nM) and demonstrated strong inhibitory activity toward human liver (HepG2), and prostate (PC3) cell lines with IC50 values of 6.60 and 11.25 µM, respectively. As well, it was safe and showed a high selectivity index against normal cell lines (WI-38). Finally, the thieno[2,3-d]pyrimidine derivative arrested the growth of the HepG2 cells at the G2/M phase inducing both early and late apoptosis. These results were further confirmed through the ability of the thieno[2,3-d]pyrimidine derivative to induce significant changes in the apoptotic genes levels of caspase-3, caspase-9, Bcl-2 associated X-protein, and B-cell lymphoma 2.

Discovery of a new potent oxindole multi-kinase inhibitor among a series of designed 3-alkenyl-oxindoles with ancillary carbonic anhydrase inhibitory activity as antiproliferative agents

An optimization strategy was adopted for designing and synthesizing new series of 2-oxindole conjugates. Selected compounds were evaluated for their antiproliferative effect in vitro against NCI-60 cell lines panel, inhibitory effect on carbonic anhydrase (CA) isoforms (hCAI, II, IX and XII), and protein kinases. Compounds 5 and 7 showed promising inhibitory effects on hCA XII, whereas compound 4d was the most potent inhibitor with low nanomolar CA inhibition against all tested isoforms. These results were rationalized by using molecular docking. Despite its lack of CA inhibitory activity, compound 15c was the most active antiproliferative candidate against most of the 60 cell lines with mean growth inhibition 61.83% and with IC₅₀ values of 4.39, 1.06, and 0.34 nM against MCT-7, DU 145, and HCT-116 cell lines, respectively. To uncover the mechanism of action behind its antiproliferative activity, compound 15c was assessed against a panel of protein kinases (RET, KIT, cMet, VEGFR1,2, FGFR1, PDFGR and BRAF) showing % inhibition of 74%, 31%, 62%, 40%, 73%, 74%, 59%, and 69%, respectively, and IC₅₀ of 1.287, 0.117 and 1.185 μM against FGFR1, VEGFR, and RET kinases, respectively. These results were also explained through molecular docking.

Characterisation of tyrosine kinase inhibitor-receptor interactions at VEGFR2 using sunitinib-red and nanoBRET

Vascular endothelial growth factor (VEGF) is an important mediator of angiogenesis, proliferation and migration of vascular endothelial cells. It is well known that cardiovascular safety liability for a wide range of small molecule tyrosine kinase inhibitors (TKIs) can result from interference with the VEGFR2 signalling system. In this study we have developed a ligand-binding assay using a fluorescent analogue of sunitinib (sunitinib-red) and full length VEGFR2 tagged on its C-terminus with the bioluminescent protein nanoluciferase to monitor ligand-binding to VEGFR2 using bioluminescence resonance energy transfer (BRET). This NanoBRET assay is a proximity-based assay (requiring the fluorescent and bioluminescent components to be within 10nm of each other) that can monitor the binding of ligands to the kinase domain of VEGFR2. Sunitinib-red was not membrane permeable but was able to monitor the binding affinity and kinetics of a range of TKIs in cell lysates. Kinetic studies showed that sunitinib-red bound rapidly to VEGFR2 at 25 °C and that cediranib had slower binding kinetics with an average residence time of 112 min. Comparison between the log K_i values for inhibition of binding of sunitinib-red and log IC₅₀ values for attenuation of VEGF₁₆₅a-stimulated NFAT responses showed very similar values for compounds that inhibited sunitinib-red binding. However, two compounds that failed to inhibit sunitinib-red binding (dasatinib and entospletinib) were still able to attenuate VEGFR2-mediated NFAT signalling through inhibition of downstream signalling events. These results suggest that these compounds may still exhibit cardiovascular liabilities as a result of interference with downstream VEGFR2 signalling.

Design, synthesis, in vitro and in silico evaluation of anti-colorectal cancer activity of curcumin analogues containing 1,3-diphenyl-1H-pyrazole targeting EGFR tyrosine kinase

Recent studies have shown that monocarbonyl analogues of curcumin (MACs) and 1H-pyrazole heterocycle both demonstrated promising anticancer activities, in which several compounds containing these scaffolds could target EGFR. In this research, 24 curcumin analogues containing 1H-pyrazole (a1-f4) were synthesized and characterized by using modern spectroscopic techniques. Firstly, synthetic MACs were screened for cytotoxicity against human cancer cell lines such as SW480, MDA-MB-231 and A549, from which the 10 most potential cytotoxic compounds were identified and selected. Subsequently, the selected MACs were further screened for their inhibition against tyrosine kinases, which showed that a4 demonstrated the most significant inhibitory effects on EGFR^WT and EGFR^L858R. Based on the results, a4 further demonstrated its ability to cause morphological changes, to increase the percentage of apoptotic cells, and to increase caspase-3 activity, suggesting its apoptosis-inducing activity on SW480 cells. In addition, the effect of a4 on the SW480 cell cycle revealed its ability to arrest SW480 cells at G₂/M phase. In subsequent computer-based assessments, a4 was predicted to possess several promising physicochemical, pharmacokinetic, and toxicological properties. Via molecular docking and molecular dynamics simulation, a reversible binding mode between a4 and EGFR^WT, EGFR^L858R, or EGFR^G719S, remained stable within the 100-ns simulation due to effective interactions especially the hydrogen bonding with M793. Finally, free binding energy calculations suggested that a4 could inhibit the activity of EGFR^G719S more effectively than other EGFR forms. In conclusion, our work would provide the basis for the future design of promising synthetic compounds as anticancer agents targeting EGFR tyrosine kinase.

Structure-Based Design of Peptides Targeting VEGF/VEGFRs

Vascular endothelial growth factor (VEGF) and its receptors (VEGFRs) play a main role in the regulation of angiogenesis and lymphangiogenesis. Furthermore, they are implicated in the onset of several diseases such as rheumatoid arthritis, degenerative eye conditions, tumor growth, ulcers and ischemia. Therefore, molecules able to target the VEGF and its receptors are of great pharmaceutical interest. Several types of molecules have been reported so far. In this review, we focus on the structure-based design of peptides mimicking VEGF/VEGFR binding epitopes. The binding interface of the complex has been dissected and the different regions challenged for peptide design. All these trials furnished a better understanding of the molecular recognition process and provide us with a wealth of molecules that could be optimized to be exploited for pharmaceutical applications.

Research progress of VEGFR small molecule inhibitors in ocular neovascular diseases

Angiogenesis is the biological process in which existing blood vessels generate new ones and it is essential for body growth and development, wound healing, and granulation tissue formation. Vascular endothelial growth factor receptor (VEGFR) is a crucial cell membrane receptor that binds to VEGF to regulate angiogenesis and maintenance. Dysregulation of VEGFR signaling can lead to several diseases, such as cancer and ocular neovascular disease, making it a crucial research area for disease treatment. Currently, anti-VEGF drugs commonly used in ophthalmology are mainly four macromolecular drugs, Bevacizumab, Ranibizumab, Conbercept and Aflibercept. Although these drugs are relatively effective in treating ocular neovascular diseases, their macromolecular properties, strong hydrophilicity, and poor blood-eye barrier penetration limit their efficacy. However, VEGFR small molecule inhibitors possess high cell permeability and selectivity, allowing them to traverse and bind to VEGF-A specifically. Consequently, they have a shorter duration of action on the target, and they offer significant therapeutic benefits to patients in the short term. Consequently, there is a need to develop small molecule inhibitors of VEGFR to target ocular neovascularization diseases. This review summarizes the recent developments in potential VEGFR small molecule inhibitors for the targeted treatment of ocular neovascularization diseases, with the aim of providing insights for future studies on VEGFR small molecule inhibitors.

An intuitionistic approach for the predictability of anti-angiogenic inhibitors in cancer diagnosis

Malignant cancer angiogenesis has historically attracted enormous scientific attention. Although angiogenesis is requisite for a child's development and conducive to tissue homeostasis, it is deleterious when cancer lurks. Today, anti-angiogenic biomolecular receptor tyrosine kinase inhibitors (RTKIs) to target angiogenesis have been prolific in treating various carcinomas. Angiogenesis is a pivotal component in malignant transformation, oncogenesis, and metastasis that can be activated by a multiplicity of factors (e.g., VEGF (Vascular endothelial growth factor), (FGF) Fibroblast growth factor, (PDGF) Platelet-derived growth factor and others). The advent of RTKIs, which primarily target members of the VEGFR (VEGF Receptor) family of angiogenic receptors has greatly ameliorated the outlook for some cancer forms, including hepatocellular carcinoma, malignant tumors, and gastrointestinal carcinoma. Cancer therapeutics have evolved steadily with active metabolites and strong multi-targeted RTK inhibitors such as E7080, CHIR-258, SU 5402, etc. This research intends to determine the efficacious anti-angiogenesis inhibitors and rank them by using the Preference Ranking Organization Method for Enrichment Evaluation (PROMETHEE- II) decision-making algorithm. The PROMETHEE-II approach assesses the influence of growth factors (GFs) in relation to the anti-angiogenesis inhibitors. Due to their capacity to cope with the frequently present vagueness while ranking alternatives, fuzzy models constitute the most suitable tools for producing results for analyzing qualitative information. This research's quantitative methodology focuses on ranking the inhibitors according to their significance concerning criteria. The evaluation findings indicate the most efficacious and idle alternative for inhibiting angiogenesis in cancer.

Medicinal Chemistry of Quinazolines as Anticancer Agents Targeting Tyrosine Kinases

Cancer is a large group of diseases that can affect any organ or body tissue due to the abnormal cellular growth with the unknown reasons. Many of the existing chemotherapeutic agents are highly toxic with a low level of selectivity. Additionally, they lead to development of therapeutic resistance. Hence, the development of targeted chemotherapeutic agents with low side effects and high selectivity is required for cancer treatment. Quinazoline is a vital scaffold well-known to be linked with several biological activities. The anticancer activity is one of the prominent biological activities of this scaffold. Several established anticancer quinazolines work by different mechanisms on the various molecular targets. The aim of this review is to present different features of medicinal chemistry as drug design, structure activity relationship, and mode of action of some targeted anticancer quinazoline derivatives. It gives comprehensive attention on the chemotherapeutic activity of quinazolines in the viewpoint of drug discovery and its development. This review provides panoramic view to the medicinal chemists for supporting their efforts to design and synthesize novel quinazolines as targeted chemotherapeutic agents.

Recent updates on thienopyrimidine derivatives as anticancer agents

Thienopyrimidine derivatives hold a unique place between fused pyrimidine compounds. They are important and widely represented in medicinal chemistry as they are structural analogs of purines. Thienopyrimidine derivatives have various biological activities. The current review discusses different synthetic methods for the preparation of heterocyclic thienopyrimidine derivatives. It also highlights the most recent research on the anticancer effects of thienopyrimidines through the inhibition of various enzymes and pathways, which was published within the last 9 years.

Graphical Abstract

Thienopyrimidine-based agents bearing diphenylurea: Design, synthesis, and evaluation of antiproliferative and antiangiogenic activity

An important role has been considered for the vascular endothelial growth factor receptor 2 (VEGFR-2) in the angiogenesis process, so that its inhibition is an important scientific way for cancer treatment. In this work, new thienopyrimidine derivatives were synthesized and evaluated. Compared with sorafenib, the majority of the target compounds had antiproliferative activity against the PC3, HepG2, MCF7, SW480, and HUVEC cell lines, especially 9h with IC₅₀ values of 4.5-15.1 μM, confirming the noticeable cytotoxic effects on the listed cell lines (PC3, HepG2, SW480, and HUVEC). Analyses by flow cytometry on SW480 and HUVEC cells revealed that 9n, 9k, 9h, and 9q led to apoptotic cell death. The result of the chick chorioallantoic membrane assay showed that 9h effectively reduced the number of corresponding blood vessels. Finally, the inhibitory effect on VEGFR-2 phosphorylation was considered as the outcome of Western blot analysis of compound 9h.

Coumarin derivatives with potential anticancer and antibacterial activity: Design, synthesis, VEGFR-2 and DNA gyrase inhibition, and in silico studies

A series of coumarin derivatives were designed, synthesized, and evaluated for their antiproliferative activity. Compound 3e exhibited significant antiproliferative activity and was further evaluated at five doses at the National Cancer Institute. It effectively inhibited vascular endothelial growth factor receptor-2 (VEGFR-2) with an IC₅₀ value of 0.082 ± 0.004 µM compared with sorafenib. While compound 3e significantly downregulated total VEGFR-2 and its phosphorylation, it markedly reduced the HUVEC's migratory potential, resulting in a significant disruption in wound healing. Furthermore, compound 3e caused a 22.51-fold increment in total apoptotic level in leukemia cell line HL-60(TB) and a 6.91-fold increase in the caspase-3 level. Compound 3e also caused cell cycle arrest, mostly at the G1/S phase. Antibacterial activity was evaluated against Gram-positive and Gram-negative bacterial strains. Compound 3b was the most active derivative, with the same minimum inhibitory concentration and minimum bactericidal concentration value of 128 μg/mL against K. pneumonia and high stability in mammalian plasma. Moreover, compounds 3b and 3f inhibited Gram-negative DNA gyrase with IC₅₀  = 0.73 ± 0.05 and 1.13 ± 0.07 µM, respectively, compared to novobiocin with an IC₅₀ value of 0.17 ± 0.02 µM. The binding affinity and pattern of derivative 3e toward the VEGFR-2 active site and compounds 3a-c and 3f in the DNA gyrase active site were evaluated using molecular modeling. Overall, ADME studies of the synthesized coumarin derivatives displayed promising pharmacokinetic properties.

Significant pharmacological activities of benzoquinazolines scaffold

Benzoquinazolines, the essential constituents of numerous well-known heterocyclic systems, have occupied a prominent position and played a significant part in the synthesis of various pharmaceutical compounds. The wide range of pharmacological effects attributed to benzoquinazolines has been the subject of extensive study. These include their roles as anticancer, antimicrobial, anti-monoamine oxidase, anticonvulsant, antiviral, antinociceptive, antioxidant, antineoplastic, antituberculosis, antiplatelet, and antiphlogistic agents. This work provides an attempt at a literature review of the pharmacological activities of benzoquinazoline derivatives, including an up-to-date account of recent research findings, and suggests avenues for future exploration in the pursuit of more potent and specific analogues for a wide range of biological targets using this platform.

Lactate anion catalyzes aminolysis of polyesters with anilines

Chemical transformation of spent polyesters into value-added chemicals is substantial for sustainable development but still challenging. Here, we report a simple, metal-free, and efficient aminolysis strategy to upcycle polylactic acid by anilines over lactate-based ionic liquids (e.g., tetrabutylammonium lactate), accessing a series of N-aryl lactamides under mild conditions. This strategy is also effective for degradation of poly(bisphenol A carbonate), affording bisphenol A and corresponding diphenylurea derivatives. It is found that, with the assistance of water, lactate anion as hydrogen-bond donor can efficiently activate carbonyl C atom of polyesters via hydrogen bonding with carbonyl O atom; meanwhile, as hydrogen-bond acceptor, it can enhance nucleophilicity of the N atom of anilines via hydrogen bonding with amino H atom. The nucleophilic attack of N atom of anilines on carbonyl C atom of polyesters results in cleavage of C─O bond of polymers and formation of the target products.

Pyrazolo[3,4-d]pyrimidine scaffold: A review on synthetic approaches and EGFR and VEGFR inhibitory activities

The pyrazolo[3,4-d]pyrimidine core has received a lot of interest from the medicinal chemistry community as a promising framework for drug design and discovery. It is an isostere of the adenine ring of adenosine triphosphate, which allows it to mimic kinase active site hinge region binding contacts. This scaffold has a wide pharmacological and biological value, one of which is as an anticancer agent. Many successful anticancer medicines have been designed and synthesized using pyrazolo[3,4-d]pyrimidine as a key pharmacophore. The main synthetic routes of pyrazolo[3,4-d]pyrimidines as well as their recent developments as promising anticancer agents acting as endothelial growth factor receptors and vascular endothelial growth factor receptor inhibitors, published in the time frame from 1999 to 2022, are summarized in this review to set the direction for the design and synthesis of novel pyrazolo[3,4-d]pyrimidine derivatives for clinical deployment in cancer treatment.

Artificial intelligence to guide precision anticancer therapy with multitargeted kinase inhibitors

BACKGROUND

Vast amounts of rapidly accumulating biological data related to cancer and a remarkable progress in the field of artificial intelligence (AI) have paved the way for precision oncology. Our recent contribution to this area of research is CancerOmicsNet, an AI-based system to predict the therapeutic effects of multitargeted kinase inhibitors across various cancers. This approach was previously demonstrated to outperform other deep learning methods, graph kernel models, molecular docking, and drug binding pocket matching.

METHODS

CancerOmicsNet integrates multiple heterogeneous data by utilizing a deep graph learning model with sophisticated attention propagation mechanisms to extract highly predictive features from cancer-specific networks. The AI-based system was devised to provide more accurate and robust predictions than data-driven therapeutic discovery using gene signature reversion.

RESULTS

Selected CancerOmicsNet predictions obtained for "unseen" data are positively validated against the biomedical literature and by live-cell time course inhibition assays performed against breast, pancreatic, and prostate cancer cell lines. Encouragingly, six molecules exhibited dose-dependent antiproliferative activities, with pan-CDK inhibitor JNJ-7706621 and Src inhibitor PP1 being the most potent against the pancreatic cancer cell line Panc 04.03.

CONCLUSIONS

CancerOmicsNet is a promising AI-based platform to help guide the development of new approaches in precision oncology involving a variety of tumor types and therapeutics.

Design, synthesis and computational study of new benzofuran hybrids as dual PI3K/VEGFR2 inhibitors targeting cancer

Design and synthesis of a new series of benzofuran derivatives has been performed. ¹H-NMR, ¹³C-NMR, elemental analysis, and IR were used to confirm the structures of the produced compounds. Hepatocellular carcinoma (HePG2), mammary gland breast cancer (MCF-7), epithelioid carcinoma cervical cancer (Hela), and human prostate cancer are used to test anticancer activity (PC3). In compared to DOX (4.17-8.87 µM), Compound 8 demonstrated the highest activity against HePG and PC3 cell lines, with an IC₅₀ range of 11-17 µM. Compound 8 inhibited PI3K and VEGFR-2 with IC₅₀ values of 2.21 and 68 nM, respectively, compared to 6.18 nM for compound LY294002 and 31.2 nM for compound sorafenib as PI3K and VEGFR-2 reference inhibitors, selectively. The molecular docking and binding affinity of the generated compounds were estimated and studied computationally utilizing molecular operating environment software as a PI3K and VEGFR-2 inhibitor (MOE). In conclusion, compound 8 exhibited significant action against hepatocellular and cervical cancer cell lines. Mechanistic study showed that it had a dual inhibitory effect against PI3K and VEGFR-2.

A Comprehensive Review of Recent Advances in the Biological Activities of Quinazolines

Quinazoline heterocycles are critical in the development of medications. Quinazoline derivatives have been intensively researched, providing a wide range of compounds with diverse biological roles. The quinazoline nucleus has garnered a lot of attention in medical chemistry in recent years. It was assumed to be a pharmacophore component in the development of physiologically interesting drugs. This review is an attempt to increase the potential of quinazoline by highlighting a wide range of advancements demonstrated by numerous derivatives of the quinazoline moiety, as well as focusing on diverse pharmacological actions of the quinazoline moiety. This review compiles recent studies on the quinazoline moiety described in the literature by researchers.

An FGFR1-Binding Peptide Modified Liposome for siRNA Delivery in Lung Cancer

Liposome modification by targeting ligands has been used to mediate specific interactions and drug delivery to target cells. In this study, a new peptide ligand, CP7, was found to be able to effectively bind to FGFR1 through reverse molecular docking and could cooperate with VEGFR3 to achieve targeting of A549 cells. CP7 was modified on the surface of the liposome to construct a targeted and safe nanovehicle for the delivery of a therapeutic gene, Mcl-1 siRNA. Due to the specific binding between CP7 and A549 cells, siRNA-loaded liposome-PEG-CP7 showed increased cellular uptake in vitro, resulting in significant apoptosis of tumor cells through silencing of the Mcl-1 gene, which is associated with apoptosis and angiogenesis. This gene delivery system also showed significantly better antitumor activity in tumor-bearing mice in vivo. All of these suggested that siRNA-loaded liposome-PEG-CP7 could be a promising gene drug delivery system with good bioavailability and minimal side effects for treatment.

Case report: apatinib plus selexipag as a novel therapy for pulmonary tumor thrombotic microangiopathy accompanied by pulmonary hypertension associated with gastric carcinoma

RATIONALE

PTTM is a rare but fatal disease, characterized by endothelial intimal proliferation and pulmonary hypertension due to micro-vascular remodeling. In view of the poor prognosis, new effective strategies are urgently required.

PATIENT CONCERNS AND DIAGNOSIS

A 51-year-old woman was admitted to hospital for acute progressive dyspnea and dry cough. Clinical tests revealed hypercoagulable state and signs of severe pulmonary hypertension, without evidence of pulmonary embolism on contrast-enhanced CT. CT showed interlobular septal thickening and diffuse ground-glass opacity. Lung perfusion scan indicated multiple segment defect. Further right heart catherization proved a significant increase in pulmonary vascular resistance.

INTERVENTIONS

A combination therapy of apatinib and selexipag was administered for treatment of PTTM. The conventional therapies of ventilation, anticoagulation and diuretic medicines were initiated after admission.

OUTCOMES

Symptoms of PTTM were ameliorated with a reduction in pulmonary artery pressure. The resolution of interlobular septal thickening and ground-glass opacity on CT constituted the clinical benefits from treatment.

LESSONS

Patient with PTTM will benefit from the combination strategy of apatinib, a VEGF-receptor antagonist, and selexipag, an oral prostacyclin receptor agonist.

Synthesis of new thienylnicotinamidines: Proapoptotic profile and cell cycle arrest of HepG2 cells

Fourteen new thienylnicotinamidines and their analogs 5a-5k, 12, 13a, and 13b were prepared and their antiproliferative potential was evaluated against the growth of 60 cancer cell lines. The tested compounds had a strong antiproliferative efficacy against almost all cancer cell lines, with the average GI₅₀ at ~2.20 µM. The effect of the thienylnicotinamidines on the growth of normal lung fibroblast cells (WI-38) indicated that these derivatives are safe to the normal cells. The selectivity index (SI) ranges from 5.5- to 42.0-fold. The conceivable mechanisms of action of the effective compounds 5d, 5f, 5g, 5i, 5j, and 5k with high SI were investigated. Although the thienylnicotinamidines are similar in structure, they could be divided into three groups as per their effects on gene expression: The first group (5d and 5f) elevated p53 and caspase 3 expression, the second group (5g and 5i) elevated p53 expression, and the last group (5j and 5k) elevated p53 and reduced topoII expression. Many thienylnicotinamides inhibited the vascular endothelial growth factor receptor-2 (VEGFR-2) in cell lysates at concentrations comparable to or better than pazopanib. The data of caspase 3 expression were confirmed by measuring the protein level by Western blot and the activity of the cleaved active enzyme. The ability to arrest the cell cycle and induce apoptosis was confirmed by flow cytometry. Taken together, two derivatives, 5d and 5f, with a distinctive VEGFR-2 inhibitory activity and a proapoptotic and cell cycle arrest profile merit further investigations.

Dual target inhibitors based on EGFR: Promising anticancer agents for the treatment of cancers (2017-)

The EGFR family play a significant role in cell signal transduction and their overexpression is implicated in the pathogenesis of numerous human solid cancers. Inhibition of the EGFR-mediated signaling pathways by EGFR inhibitors is a widely used strategy for the treatment of cancers. In most cases, the EGFR inhibitors used in clinic were only effective when the cancer cells harbored specific activating EGFR mutations which appeared to preserve the ligand-dependency of receptor activation but altered the pattern of downstream signaling pathways. Moreover, cancer is a kind of multifactorial disease, and therefore manipulating a single target may result in treatment failure. Although drug combinations for the treatment of cancers proved to be successful, the use of two or more drugs concurrently still was a challenge in clinical therapy owing to various dose-limiting toxicities and drug-drug interactions caused by pharmacokinetic profiles changed. Therefore, a single drug targeting two or multiple targets could serve as an effective strategy for the treatment of cancers. In recent, drugs with diverse pharmacological effects have been shown to be more advantageous than combination therapies due to their lower incidences of side effects and more resilient therapies. Accordingly, dual target-single-agent strategy has become a popular field for cancer treatment, and researchers became more and more interest in the development of novel dual-target drugs in recent years. In this review, we briefly introduce the EGFR family proteins and synergisms between EGFR and other anticancer targets, and summarizes the development of potential dual target inhibitors based on wild-type and/or mutant EGFR for the treatment of solid cancers in the past five years. Additionally, the rational design and SARs of these dual target agents are also presented in detailed, which will lay a significant foundation for the further development of novel EGFR-based dual inhibitors with excellent druggability.

2,3-Difunctionalized Benzo[b]thiophene Scaffolds Possessing Potent Antiangiogenic Properties

A new class of 2-anilino-3-cyanobenzo[b]thiophenes (2,3-ACBTs) was studied for its antiangiogenic activity for the first time. One of the 2,3-ACBTs inhibited tubulogenesis in a dose-dependent manner without any toxicity. The 2,3-ACBTs significantly reduced neovascularization in both ex vivo and in vivo angiogenic assays without affecting the proliferation of endothelial cells. Neovascularization was limited through reduced phosphorylation of Akt/Src and depolymerization of f-actin and β-tubulin filaments, resulting in reduced migration of cells. In addition, the 2,3-ACBT compound disrupted the preformed angiogenic tubules, and docking/competitive binding studies showed that it binds to VEGFR2. Compound 2,3-ACBT had good stability and intramuscular profile, translating in suppressing the tumor angiogenesis induced in a xenograft model. Overall, the present study suggests that 2,3-ACBT arrests angiogenesis by regulating the Akt/Src signaling pathway and deranging cytoskeletal filaments of endothelial cells.

Imidazo[1,2-b]pyridazine as privileged scaffold in medicinal chemistry: An extensive review

Imidazo[1,2-b]pyridazine scaffold represents an important class of heterocyclic nucleus which provides various bioactives molecules. Among them, the successful kinase inhibitor ponatinib led to a resurgence of interest in exploring new imidazo[1,2-b]pyridazine-containing derivatives for their putative therapeutic applications in medicine. This present review intends to provide a state-of-the-art of this framework in medicinal chemistry from 1966 to nowadays, unveiling different aspects of its structure-activity relationships (SAR). This extensive literature surveil may guide medicinal chemists for the quest of novel imidazo[1,2-b]pyridazine compounds with enhanced pharmacokinetics profile and efficiency.

Therapeutic strtegies of glioblastoma (GBM): The current advances in the molecular targets and bioactive small molecule compounds

Glioblastoma (GBM) is the most common aggressive malignant tumor in brain neuroepithelial tumors and remains incurable. A variety of treatment options are currently being explored to improve patient survival, including small molecule inhibitors, viral therapies, cancer vaccines, and monoclonal antibodies. Among them, the unique advantages of small molecule inhibitors have made them a focus of attention in the drug discovery of glioblastoma. Currently, the most used chemotherapeutic agents are small molecule inhibitors that target key dysregulated signaling pathways in glioblastoma, including receptor tyrosine kinase, PI3K/AKT/mTOR pathway, DNA damage response, TP53 and cell cycle inhibitors. This review analyzes the therapeutic benefit and clinical development of novel small molecule inhibitors discovered as promising anti-glioblastoma agents by the related targets of these major pathways. Meanwhile, the recent advances in temozolomide resistance and drug combination are also reviewed. In the last part, due to the constant clinical failure of targeted therapies, this paper reviewed the research progress of other therapeutic methods for glioblastoma, to provide patients and readers with a more comprehensive understanding of the treatment landscape of glioblastoma.

Synthesis, in vitro anticancer activity and in silico studies of certain isoxazole-based carboxamides, ureates, and hydrazones as potential inhibitors of VEGFR2

The ensuing research presents the results of in vitro anticancer activity of novel 28 compounds of isoxazole-based carboxamides 3(a-d); ureates 4(a-g), 5, 6, 7a,b, 8; and hydrazones 9(a-f), 10(a-d), 11a,b as potential inhibitors of VEGFR2. The carboxamides and ureates were synthesized by converting 5-(aryl)-isoxzaole-3-carbohydrazides 1a,b to the corresponding carbonylazides 2a,b followed by treatment with the appropriate amines. The hydrazones were directly obtained through condensation of the carbohydrazide 1a,b with aldehydes and/or ketones. The structures of the target compounds were confirmed by elemental and spectral analyses. A preliminary in vitro anticancer screening of solutions (10^-5M) on 60 cancer cell lines (NCI, USA) revealed that the carboxamide 3c is the most promising growth inhibitor. Explicitly, 3c showed potent anticancer activity at 10µ M against leukemia (HL-60(TB), K-562 and MOLT-4), colon cancer (KM12) and melanoma (LOX IMVI) cell lines with %GI range = 70.79-92.21. Evaluation of growth inhibitory activity of the synthesized compounds against hepatocellular carcinoma (HepG2), that overexpresses VEGFR2, showed superior activity of compounds 8, 10a and 10c with IC₅₀ in sub micromolar concentrations of 0.84, 0.79 and 0.69 μM, respectively, which is better than that of the reference drug, Sorafenib (IC₅₀ = 3.99 µM). Moreover, these compounds displayed high selective cytotoxicity for HepG2 cancer cells over the nontumorigenic THLE2 liver cells (SI range = 26.37-38.60) which reflect their safety. The results of VEGFR2 kinase inhibition assay demonstrate that, compounds 8 and 10a are the most active inhibitors with IC₅₀ = 25.7 and 28.2 nM, respectively, (Sorafenib IC₅₀ = 28.1 nM). Molecular docking of the synthesized derivatives to VEGFR2 (PDB: 3WZE) showed similar binding modes to that of the co-crystallized ligand, sorafenib. Moreover, the results of computational assessment of ADME and drug-likeness characteristics inspire further investigations of the new isoxazole-based derivatives to afford more potent, safe and orally active VEGFR2 inhibitors as potential anticancer drug candidates.

Design, synthesis and biological evaluation of dual HDAC and VEGFR inhibitors as multitargeted anticancer agents

Herein, a novel series of dual histone deacetylase (HDAC) and vascular endothelial growth factor receptor (VEGFR) inhibitors were designed, synthesized and biologically evaluated based on previously reported pazopanib-based HDAC and VEGFR dual inhibitors. Most target compounds showed significant HDAC1, HDAC6 and VEGFR2 inhibition, which contributed to their potent antiproliferative activities against multiple cancer cell lines and significant antiangiogenic potencies in both human umbilical vein endothelial cell (HUVEC) tube formation assays and rat thoracic aorta ring assays. Further HDAC selectivity evaluations indicated that hydroxamic acids 5 and 9e possessed HDAC isoform selectivity profiles similar to that of the approved HDAC inhibitor suberoylanilide hydroxamic acid(SAHA), while hydrazide12 presented an HDAC isoform selectivity profilesimilar to that of the clinical HDAC inhibitor MS-275. The VEGFR inhibition profiles of 5, 9e and 12 were similar to that of the approved VEGFR inhibitor pazopanib. The intracellular target engagements of Compounds 5 and 12 were confirmed by western blot analysis. The metabolic stabilities of 5, 9e and 12 in mouse liver microsomes were inferior to that of pazopanib. These dual HDAC and VEGFR inhibitors provide lead compounds for further structural optimization to obtainpolypharmacological anticancer agents.

Current progress, challenges and future prospects of indazoles as protein kinase inhibitors for the treatment of cancer

The indazole core is an interesting pharmacophore due to its applications in medicinal chemistry. In the past few years, this moiety has been used for the synthesis of kinase inhibitors. Many researchers have demonstrated the use of indazole derivatives as specific kinase inhibitors, including tyrosine kinase and serine/threonine kinases. A number of anticancer drugs with an indazole core are commercially available, e.g. axitinib, linifanib, niraparib, and pazopanib. Indazole derivatives are applied for the targeted treatment of lung, breast, colon, and prostate cancers. In this review, we compile the current development of indazole derivatives as kinase inhibitors and their application as anticancer agents in the past five years.

New N-(1,3,4-thiadiazol-2-yl)furan-2-carboxamide derivatives as potential inhibitors of the VEGFR-2

The present study reports the synthesis and biological evaluation of a new series of novel N-(1,3,4-thiadiazol-2-yl)furan-2-carboxamide derivatives. The reactions were executed under both conventional and microwave irradiation conditions. An enhancement in the synthetic yields and rates was observed when the reactions were carried out under the microwave compared with the classical conditions. The structures of the products were ascertained by different analytical and spectral analyses. The antiproliferative activities were evaluated against three human epithelial cell lines; breast (MCF-7), colon (HCT-116), and prostate (PC-3) using MTT assay technique and doxorubicin was utilized as a reference drug. Besides, molecular docking studies were also performed and the vascular endothelial growth factor recptor-2 (VEGFR-2) was identified as a potential molecular target. Compounds 6, 7, 11a, 11b, 12, 14, and 16 showed promising antiproliferative activity against the three cancer cell lines investigated. Compounds 2 and 15b had significant antiproliferative activities against only colon and breast cells but not against the prostate cells. All the active antiproliferative compounds were highly selective. All the active antiproliferative compounds were good inhibitors of the VEGFR-2 at 7.4-11.5 nM compared with Pazopanib. Compound 7 with the most favorable orientation to the VEGFR-2 from the docking studies, was also the best inhibitor of the receptor. The antiproliferative activity of these compounds is in partial caused by their ability to inhibit the VEGFR-2 and since other molecular targets were not examined, other possibilities cannot be ruled out.

Novel thienopyrimidine-aminothiazole hybrids: Design, synthesis, antimicrobial screening, anticancer activity, effects on cell cycle profile, caspase-3 mediated apoptosis and VEGFR-2 inhibition

A series of novel hybrid compounds of hexahydrobenzo[4,5]thieno[2,3-d]pyrimidine with aminothiazole scaffolds were synthesized. The synthesized compounds were evaluated for their cytotoxic activity against the NCI-60 human tumor cell line panel. Compounds 7c, 7d and 7e exhibited significant antiproliferative activities at 10^-5 M dose. Compound 7c exhibited excellent cytotoxic activity against CNS cancer cell lines including SNB-75 and SF-295 as well as renal cancer cell line CAKI-1 when compared with sorafenib as standard anticancer drug. In addition, compound 7d showed almost comparable anticancer activity to sorafenib against SNB-75 cell line and displayed moderate activity against SF-295 and CAKI-1 cell lines in comparison to sorafenib. Compound 7c inhibited the vascular endothelial growth factor receptor 2 (VEGFR-2) with IC₅₀ of 62.48 ± 3.7 nM and decreased both total VEGFR-2 and phosphorylated VEGFR-2 in treated SNB-75 cells suggesting its ability to down regulate cell proliferation, growth, and survival.. The flow cytometric analysis showed that 7c displayed its cytotoxic activity through the reduction of the cellular proliferation and induction of cell cycle arrest at the G2/M phase. Compound 7c clearly boosted the level of the apoptotic caspase-3. All the synthesized compounds were also screened for their antibacterial and antifungal activity against four pathogenic strains of both Gram-positive and Gram-negative as well as Candida albicans. Only compound 7d exhibited antifungal activity against Candida albicans compared to nystatin as the standard antifungal compound.

Anti-angiogenic Agents: A Review on Vascular Endothelial Growth Factor Receptor-2 (VEGFR-2) Inhibitors

Tumor growth inhibition can be achieved by inhibiting angiogenesis, which has been a field of great concern in recent years. Important targets to inhibit angiogenesis include vascular endothelial growth factor receptor (VEGFR) and its homologous tyrosine kinase receptor. Anti-angiogenic therapy based on inhibition of VEGFR-2 is an effective clinical treatment strategy. The research progress of VEGFR-2 inhibitors is reviewed in this paper from the aspects of drug development and chemical synthesis.

Synthesis of New Dialkyl 2,2′-[Carbonylbis(azanediyl)]dibenzoates via Curtius Rearrangement

The 2-(alkylcarbonyl)benzoic acids obtained by esterification of phthalic anhydride are converted into azide derivatives: alkyl 2-[(azidocarbonyl)amino]benzoates and to ureas: dialkyl 2,2′-[carbonylbis(azanediyl)]dibenzoates. These transformations were carried out using classical Curtius rearrangement conditions in the presence of diphenylphosphoryl azide (DPPA) in a basic medium, followed by hydrolysis. Subsequently, a final condensation reaction of these urea derivatives enabled us to obtain, for the first time, the new alkyl derivatives, alkyl 2-[2,4-dioxo-1,2-dihydroquinazolin-3(4H)-yl]benzoates. All the new compounds obtained in satisfactory yields were characterized by 1H and 13C NMR, and by X-ray crystallographic analysis.

Discovery of thieno[2,3-d]pyrimidine-based derivatives as potent VEGFR-2 kinase inhibitors and anti-cancer agents

Vascular endothelial growth factor-2 (VEGFR-2) is considered one of the most important factors in tumor angiogenesis, and consequently a number of anticancer therapeutics have been developed to inhibit VEGFR-2 signaling. Accordingly, eighteen derivatives of thieno[2,3-d]pyrimidines having structural characteristics similar to VEGFR-2 inhibitors were designed and synthesized. Anticancer activities of the new derivatives were assessed against three human cancer cell lines (HCT-116, HepG2, and MCF-7) using MTT. Sorafenib was used as positive control. Compounds 17c-i, and 20b showed excellent anticancer activities against HCT-116 and HepG2 cell lines, while compounds 17i and 17g was found to be active against MCF-7 cell line. Compound 17f exhibited the highest cytotoxic activities against the examined cell lines, HCT-116 and HepG2, with IC₅₀ values of 2.80 ± 0.16 and 4.10 ± 0.45 µM, respectively. Aiming at exploring the mechanism of action of these compounds, the most active cytotoxic derivatives were in vitro tested for their VEGFR-2 inhibitory activity. Compound 17f showed high activity against VEGFR-2 with an IC₅₀ value of 0.23 ± 0.03 µM, that is equal to that of reference, sorafenib (IC₅₀ = 0.23 ± 0.04 µM). Molecular docking studies also were performed to investigate the possible binding interactions of the target compounds with the active sites of VEGFR-2. The synthesized compounds were analyzed for their ADMET and toxicity properties. Results showed that most of the compounds have low to very low BBB penetration levels and they have non-inhibitory effect against CYP2D6. All compounds were predicted to be non-toxic against developmental toxicity potential model except compounds 17b and 20b.