Scaffold hopping and redesign approaches for quinazoline based urea derivatives as potent VEGFR-2 inhibitors

Exploration of cytotoxicity of iodoquinazoline derivatives as inhibitors of both VEGFR-2 and EGFRT790M: Molecular docking, ADMET, design, and syntheses

Novel inhibitors of epidermal growth factor receptor (EGFR)T790M/vascular endothelial growth factor receptor-2 (VEGFR-2) were synthesized based on the iodoquinazoline scaffold linked to different heteroaromatic, aromatic, and/or aliphatic moieties. The novel derivatives were in vitro examined for anticancer activities against A549, HCT116, michigan cancer foundation-7 (MCF-7), and HepG2 cells. Molecular modeling was applied to discover their orientation of binding with both VEGFR-2 and EGFR active sites. Compounds 8d, 8c, 6d, and 6c indicated the highest cytotoxicity with IC50 = 6.00, 6.90, 6.12 and 6.24 µM, 7.05, 7.35, 6.80, and 6.80 µM, 5.75, 7.50, 6.90, and 6.95 µM, and 6.55, 7.88, 7.44, and 7.10 µM against the A549, HepG2, HCT116, and MCF-7 cell lines, correspondingly. The cytotoxicity against normal VERO (normal african green monkey kidney cells) of the extremely active eight compounds 6a-d and 8a-d was evaluated. Our compounds exhibited low toxicity concerning normal VERO cells with IC50 = 45.66-51.83 μM. Furthermore, inhibition assays for both the EGFRT790M and VEGFR-2 enzymes were done for all compounds. Remarkable inhibition of EGFRT790M activity was achieved with compounds 6d, 8d, 6c, and 8c at IC50 = 0.35, 0.42, 0.48, and 0.50 µM correspondingly. Moreover, remarkable inhibition of VEGFR-2 activity was achieved with compounds 8d, 8c, 6d, and 6c at IC50 = 0.92, 0.95, 1.00, and 1.20 µM correspondingly. As planned, derivatives 6d, 8d, 6c, and 8c presented exceptional inhibition of both EGFRT790M/VEGFR-2 activities. Finally, in silico absorption, distribution, metabolism, excretion and toxicity (ADMET) studies were made for the highly active four compounds 6c, 6d, 8c, and 8d in comparison with erlotinib and sorafenib as reference standards.

Targeting cancer using scaffold-hopping approaches: illuminating SAR to improve drug design

Scaffold hopping is a design approach involving alterations to the core structure of an already bioactive scaffold to generate novel molecules to discover bioactive hit compounds with innovative core structures. Scaffold hopping enhances selectivity and potency while maintaining physicochemical, pharmacodynamic (PD), and pharmacokinetic (PK) properties, including toxicity parameters. Numerous molecules have been designed based on a scaffold-hopping strategy that showed potent inhibition activity against multiple targets for the diverse types of malignancy. In this review, we critically discuss recent applications of scaffold hopping along with essential components of medicinal chemistry, such as structure-activity relationship (SAR) profiles. Moreover, we shed light on the limitations and challenges associated with scaffold hopping-based anticancer drug discovery.

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.

Role of heterocycles in inhibition of VEGFR-2 - a recent update (2019-2022)

The literature reveals that oncogenic protein kinase inhibition has been proved to be a successful anticancer approach. The vascular endothelial growth factor receptor (VEGFR) kinase plays an important role in angiogenesis and metastasis. VEGFR-2 has an upper hand in the angiogenesis process. Vascular endothelial growth factor activates VEGFR-2 which initiates tumor angiogenesis. In addition, VEGFRs are associated with numerous other diseases. Hence, inhibition of VEGFRs is an attractive approach for cancer treatment. In view of this, researchers designed and discovered small molecular heterocycle-based VEGFR-2 inhibitors and some of them have been approved by the Food and Drug Administration (FDA). However, these VEGFR-2 inhibitors pose adverse side effects such as cardiovascular problems, diarrhea, and renal function impairment. Research indicates that combination of certain pharmacophores exhibits excellent VEGFR inhibitory activity. In particular, combination of heterocycles paved the way to efficient VEGFR inhibitors. In this review, the research focusing on VEGFR inhibitory activity has been discussed along with the structure-activity relationship. In addition to emphasizing the most potent molecule among the set of designed molecules, structural features responsible for such an activity are described. This review may aid in designing potent VEGFR inhibitors.

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.

Iodoquinazoline-derived VEGFR-2 and EGFRT790M dual inhibitors: Design, synthesis, molecular docking and anticancer evaluations

Herein, we report the synthesis of a series of new fourteen iodoquinazoline derivatives 7a-c to 13a-e and their evaluation as potential anticancer agents via dual targeting of EGFRT790M and VEGFR-2. The new derivatives were designed according to the target receptors structural requirements. The compounds were evaluated for their cytotoxicity against HepG2, MCF-7, HCT116 and A549 cancer cell lines using MTT assay. Compound 13e showed the highest anticancer activities with IC50 = 5.70, 7.15, 5.76 and 6.50 µM against HepG2, MCF-7, HCT116 and A549 cell lines correspondingly. Compounds 7c, 9b and 13a-d exhibited very good anticancer effects against the tested cancer cell lines. The highly effective six derivatives 7c, 10, 13b, 13c, 13d and 13e were examined against VERO normal cell lines to estimate their cytotoxic capabilities. Our conclusion revealed that compounds 7c, 10, 13b, 13c, 13d and 13e possessed low toxicity against VERO normal cells with IC50 prolonging from 41.66 to 53.99 μM. Also compounds 7a-c to 13a-e were further evaluated for their inhibitory activity against EGFRT790M and VEGFR-2. Also, their ability to bind with both EGFR and VEGFR-2 receptors was examined by molecular modeling. Compounds 13e, 13d, 7c and 13c excellently inhibited VEGFR-2 activity with IC50 = 0.90, 1.00, 1.25 and 1.50 µM respectively. Moreover, Compounds 13e, 7c, 10 and 13d excellently inhibited EGFRT790M activity with IC50 = 0.30, 0.35, 0.45 and 0.47 µM respectively. Finally, our derivatives 7b, 13d and 13e showed good in silico calculated ADMET profile.

Design, synthesis, and evaluation of new benzimidazole‏ ‏‎thiourea ‎derivatives as antitumor agents

Novel benzimidazole thiourea derivatives were designed and synthesized based on sorafenib as a lead compound. The benzimidazole moiety was traded by the pyridine ring to enhance the hydrophobic interaction and retain hydrogen bonding in the hinge region, while lipophilic moieties with different bulkiness were employed in the deep hydrophobic pocket for better hydrophobic interactions. Thiourea as a urea bioisostere was also utilized. Substantial activity was demonstrated against a leukemia subpanel in an in vitro antitumor screening at the NCI. In the single-dose assay, compounds 7i, 7j, and 7l had a GI%) higher than sorafenib against most leukemia cell lines (GI% = 86.2%-137.1%), while in the five-dose assay, compound 7l outperformed sorafenib against the HL-60(TB) and SR leukemia cell lines in terms of GI50 , TGI, and LC50 . Compound 7l also caused cycle arrest at the G0-G1 and S phases in the HL-60(TB) leukemia cell line and induced apoptosis via elevating the Bax/Bcl-2 ratio and increasing caspases 3, 7, and 9 by 5.1-, 3.2-, and 5.2-fold, respectively. Compounds 7i, 7j, and 7l also inhibited the vascular ‎endothelial growth factor receptor-2 (VEGFR-2), B-Raf(V600E) , and platelet-derived growth factor receptor ‎beta (PDGFR-β) enzymes with an IC50 range of 0.063-0.44 μM. COMPARE analysis and a molecular docking study were also performed to predict the possible mechanism of action and binding mode, respectively.

New quinazoline sulfonamide derivatives as potential anticancer agents: Identifying a promising hit with dual EGFR/VEGFR-2 inhibitory and radiosensitizing activity

Herein, we report the synthesis of a series of new quinazoline sulfonamide conjugates 2-16 and their evaluation as potential anticancer agents via dual targeting of EGFRT790M and VEGFR-2. The newly synthesized compounds were designed based on the structure requirements of the target receptors and were confirmed using spectral data. The compounds were evaluated for their cytotoxicity against four cancer cell lines (HepG2, MCF-7, HCT116 and A549) using MTT assay. The most active compounds were further evaluated for their inhibitory activity against EGFRT790M and VEGFR-2. Compound 15 showed the most significant cytotoxic activity with IC50 = 0.0977 µM against MCF-7 and the most potent inhibitory activity against both EGFR and VEGFR with IC50 = 0.0728 and 0.0523 µM, respectively. Compound 15 was able to induce apoptosis in MCF-7 cells and cell cycle arrest at the G2/M phase. The relative safety profile of 15 was assessed using HEK-293 normal cell line and an ADMET profile was carried out. Radiosensitizing evaluation of 15 proved its significant ability to sensitize the cancer cell to the effect of radiation after being subjected to a single dose of 8 Gy gamma irradiation. Molecular docking studies revealed that 15 could bind to the ATP-binding site of EGF and VEGF receptors, inhibiting their activity.

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.

Novel 2-oxo-2-phenylethoxy and benzyloxy diaryl urea hybrids as VEGFR-2 inhibitors: Design, synthesis, and anticancer evaluation

Two series of diaryl urea derivatives, 6a-k and 7a-n, were synthesized. All the newly synthesized compounds were tested against the NCI (US) cancer cell lines via SRB assay. The p-chloro-m-trifluoromethyl phenyl derivatives 6e-g and 7e-g showed the most potent cytotoxic activity with a GI₅₀ value range of 1.2-15.9 µM. Furthermore, the p-fluorobenzyloxy diaryl urea derivative 7g revealed the most potent cytotoxicity against eight cancer cell lines in the MTT assay with IC₅₀ values below 5 µM. Compounds 6a-k and 7a-n were tested for their vascular endothelial growth factor receptor-2 (VEGFR-2) kinase inhibitory activities. The p-chloro-m-trifluoromethyl diaryl urea benzyloxy derivatives 7e-i and the p-methoxydiaryl urea benzyloxy derivatives 7k, 7l, and 7n were found to be the most active compounds as VEGFR-2 inhibitors in the benzyloxy series 7, with an IC₅₀ range of 0.09-4.15 µM. In the 2-oxo-2-phenylethoxy series 6, compounds 6e-g and 6i were reported with IC₅₀ values of 0.94, 0.54, 2.71, and 4.81 µM, respectively. Moreover, compounds 7e and 7g induced apoptosis, causing cell cycle arrest in the G2/M phase. In addition, 7g showed an antimigratory effect in A-375 cells and inhibited the VEGFR-2 expression in an immunohistofluorescence study. Molecular docking simulations on VEGFR-2 as well as ADME properties prediction were also performed.

An appraisal of anticancer activity with structure-activity relationship of quinazoline and quinazolinone analogues through EGFR and VEGFR inhibition: A review

Cancer is one of the leading causes of death. Globally a huge number of deaths and new incidences are reported annually. Heterocyclic compounds have been proved to be very effective in the treatment of different types of cancer. Among different heterocyclic scaffolds, quinazoline and quinazolinone core were found versatile and interesting with many biological activities. In the discovery of novel anticancer agents, the Quinazoline core is very effective. The FDA has approved more than 20 drugs as an anticancer bearing quinazoline or quinazolinone core in the last two decades. One prime example is Dacomitinib, which was newly approved for non-small-cell lung carcinoma treatment in 2018. These drugs work by different pathways to prevent the spread of cancer cell progression, including inhibition of different kinases, tubulin, kinesin spindle protein, and so forth. This review presented recent developments of quinazoline/quinazolinone scaffold bearing derivatives as anticancer agents acting as epidermal growth factor receptor (EGFR) vascular endothelial growth factor receptor (VEGFR), and dual EGFR/VEGFR inhibitors.

Recent advances in, and challenges of, anti-angiogenesis agents for tumor chemotherapy based on vascular normalization

A major problem associated with cancer treatment is resistance-prone chemotherapeutic drugs. An increasing number of studies have documented that the occurrence of resistance tends to be associated with abnormal blood vessels. In 2001, Jain proposed the vascular normalization theory, which was recently applied to the drug-resistant treatment of tumors in the clinic. Through the intervention of angiogenesis inhibitors, remodeling the structure and function of abnormal vessels can maximize the efficacy of chemotherapeutic drugs. In this review, we systematically describe the occurrence and progress of tumor angiogenesis, as well as the pathological characteristics of tumor blood vessels. Moreover, druggable targets for vascular normalization and the development of related inhibitors are also outlined.

Discovery of potent thieno[2,3-d]pyrimidine VEGFR-2 inhibitors: Design, synthesis and enzyme inhibitory evaluation supported by molecular dynamics simulations

Vascular endothelial growth factor receptor (VEGFR) is one of the well-known targets that control angiogenesis and cancer progression. In this study, we are reporting the design, synthesis and biological evaluation of a series of 4-substituted thieno[2,3-d]pyrimidine derivatives as VEGFR-2 inhibitors. The design of these compounds was based on interactions extracted from crystal structure of potent pyrrolo[3,2-d]pyrimidine inhibitor VIII with VEGFR-2 (PDB: 3VHE). In addition to these interactions, the new compounds were also designed to interact with residues in the solvent accessible region such as Asn923. Accordingly, the thienopyrimidine target compounds were synthesized and subjected to VEGFR-2 enzyme inhibition assay. Several target compounds (7d-f, 8b-c, 8e-g and 15c) exhibited potent inhibitory activities against VEGFR-2 with IC₅₀ values in low nanomolar range. Compounds 8b and 8e revealed exceptionally potent inhibitory activity with IC₅₀ of 5 and 3.9 nM, respectively. The molecular docking analysis and molecular dynamics simulation were also performed to further investigate these findings.